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Design Document - University of Central Florida

1. Figure 3 33 DS1624 functioning diagram 3 10 Microcontroller Microcontroller unit would be the brain of the IRPS since its duties will be monitoring the status of different components and take decision to regulate the safeness of those Microcontroller will continually execute requests to a variety of sensors in IRPS Such interaction will allow a continuous monitoring of IRPS performance and possible failures or prevent failures to occur Chosen microcontroller must be capable to run a fast clock speed being low power consumption device having enough appropriate analog and digital I O ports to interact with sensors and LCD display and have small size to be integrated on designed board At this moment our project have identified the need of having 3 voltage sensors 2 current sensors and 1 temperature sensors total to be used could increase or decrease and also it was identified that some output ports are necessary to display readings to LCD Since our system will be fed by two renewable sources and some extensive monitoring is desired it is devised that probably more than one microcontroller will be needed to split the load and gain a close multitasking operation Decision about if one unit or more are needed will depend on balanced between cost performance and overall safety nevertheless it is aimed that selected microcontroller unit meet the following model Low cost on the unit and desirable on the development board as well Low
2. Table 6 1 2 Layer Printed Circuit Board Specification Table 6 2 4 Layer Printed Circuit Board Specification Table 7 1 Microcontroller Testing Plan Part 1 Table 7 2 Microcontroller Testing Plan Part 2 Table 7 3 LCD Testing Plan Table 7 4 Voltage sensor Testing Plan Table 7 5 Current sensor Testing Plan Table 7 6 Temperature sensor Testing Plan Table 7 7 Microcontroller Alternative Charging Modes Table 8 1 Gantt Chart Depicting Research Timeline Table 8 2 Gantt Chart Depicting Design Timeline Table 8 3 Gantt Chart Depicting Parts Acquisition Timeline Table 8 4 Gantt Chart Depicting Prototyping Timeline Table 8 5 Gantt Chart Depicting Testing Timeline Table 8 6 Anticipated Budgets Table 8 7 PV installations in the United States Table 8 8 Units Sold Projection 48 49 50 58 60 64 66 67 67 70 71 84 85 87 100 101 106 107 107 108 108 109 109 114 115 116 117 117 118 124 124 xviii
3. There are several factors for the conversion efficiency some of them are reflectance thermodynamic charge carrier separation and conduction efficiency 7 These aspects can be difficult to determine so the project will be using data found through research of each type of solar cell s specs As can be seen below in Figure 3 1 which is plot of efficiency versus time the two different types of solar cells which are being considering silicon and thin film are both represented Best Research Cell Efficiencies NREL Multijunction Cells 2 terminal monolithic Thin Film Technologies Spectrolab Fraunhofer ISE Boeing 48 Three junction concentrator Cu In Ga Se metamorphic 299x metamorphic 454x Spectrolab Solar Y Three junction non concentrator oCdTe ates vpi Spre Juncti A Two junction concentrator Amorphous Si H stabilized 9 Semiconductor serra j x ing Spectrol Boeing lab tar 44 Single Junction GaAs Nano micro poly Si jeen TD Bosra See A qs 400 3 av O Multijunction polycrystalline i OS ASingle crystal NREL AConcentrator Emerging PV inverted metamorphic Ba bie inverted rate 40 Y Thin film crystal oDye sensitized cells vie 1 z 8x tamor Organic cells various types mes Tx Sharp Crystalline Si Cells IMM 1 sun 36 m Single crystal 4 Organic tandem cells Peet NREL inverted Bee Av
4. 100 Discharge Cost Low Very High High and High High auxiliary heating systems needed Lifespan 1000 3000 2500 3000 2000 Cycles Efficiency 72 78 100 89 72 78 75 Self Average Negligible Negligible High Negligible discharge Maturity of Mature Immature Mature Mature Immature Technology Table 3 5 Key Battery Attributes Comparison 48 59 3 13 2 Lead Acid Battery Lead Acid batteries are the most commonly used form of batteries among all of the rechargeable batteries in power application Nevertheless there are still some limiting factors that affect the power efficiency in a stand alone power generation 3 13 2 1 Limitation The limitations are the following e Due to the limited power density of the Lead Acid batteries the time that will take the battery to be charged is considerable Furthermore the amount of energy will be able to deliver to the system is significant e Lead Acid batteries have a life span of 1000 to 2000 cycles on its depth of discharge of 75 It is relatively shorter comparing to the other four forms of batteries As a consequence Lead Acid batteries need to be replaced regularly 48 e Lead Acid batteries are large in size relative to the other forms of batteries They have a very low energy to weight ratio and a low energy to volume ratio 3 13 2 2 Advantages Despite the limiting factors of Lead Acid batteries their advantages over other types of batteries still
5. 593 North C South Time zone Longitude a S sa Eastin west GMT 05 00 Eastern Time US amp Canada Colombia X Data source Enter monthly averages Import time series data file Get Data Via Internet Baseline data FEE a Month Clearness Daily Radiation e Global Horizontal Radiation an Index kWh m2 d January 0 456 1 780 Sol February 0 495 2 630 E March 0 516 3 800 g4 April 0 486 460 May 0 493 5 410 23 3 June 0 498 57803 a a2 3 July 0 498 5 610 5 August 0 509 5 090 3 _September 0 512 4 130 October 0 502 2 970 0 0 0 inace 0 444 1 870 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec jes ell Daily Radiation Cleamess Index December 0 435 1 510 Average 0 493 3 771 Data Source Plot Expott Scaled annual average kwh n d 3 77 i Help Cancel OK Figure 8 1 Solar resources entered to simulate power output for state of Connecticut Each state average power output was calculated then it was proceeded to do the economic analysis given the average annual consumption KWH in each US state for both residential and small businesses In addition it was considered the price per kilowatt hours given that each state has its own rate 56 The analysis was based on 30 years of project life and both financed and paid off systems for financed system we only took into consideration a fixed 10 of down payment 120 8 2 2 1 Final Client Price Toward calculating final cli
6. MiddleAtlantic Residential West North Central Residential H East SouthCentral Residential W Mountain Residential I Pacific Noncontiguous Residential Hi Middle Atiantic Commercial E West North Central Commercial East SouthCentral Commercial Mountain Commercial Pacific Noncontiguous Commercial Figure 8 2 NPV for systems on commercial and residential sector in each USA regional division and state From the economic analysis perspective after NPVs calculation and observing above Figure 8 2 it is conclude that scaled up IRPS version possess a more secure market on the residential sector given that is a system with not enough power produced to cover commercial sector although in the New England some states of Middle Atlantic and Pacific Noncontiguous USA regional divisions could have a great acceptance on the small businesses arena as well given the climatic conditions and high energy rates 8 2 2 2 Analysis of Profitability Based on previous market analysis it is chosen to focus on development for the residential sector so now the profitability of the project in the residential sector must be analyzed The main competition is the traditional photovoltaic system This analysis seeks to improve on the traditional model by adding wind energy generating capabilities to provide energy in different types of weather Because PV systems were identified as the competition they were used to project sales for scaled up IRPS From the Open PV
7. Red boxes and arrows are specially used to denote critical system errors status and action to take upon it Finally green boxes and arrows are meant to define successful checking of some components correct availability Controller box will perform fourth main stages and each one of them includes more than one mode or procedure First stage is composed by Check Batteries mode Check Temperature mode and System Output mode Second stage will be composed of two main modes Threshold Algorithm and Storage Bank Third stage or Charging Procedure is the most complex in the functionality diagram Finally fourth stage or LCD Display will wrap around any variable value or alert to make a custom format message and will interact with LCD device to display final outcome 98 As it was mentioned previously the Atmel AT91SAM7X512 microcontroller would be used in IRPS pre loaded with the preference of Netduino boot loader This microcontroller contains the adequate hardware and software for all design goals providing enough digital and analog pins to handle all sensors LCD and battery charging check meanwhile at the same time being able to control the IRPS circuitry using pulse width modulation PWM outputs LCD chosen was 20x4 characters LCD 09568 from vendor SparkFun Electronics The actual LCD is 87 3 x 41 8 mm while the PCB footprint measures 105 x 59 9 mm This display is monochrome black on green and h
8. The most suitable one found so far is the LT1160 by Linear Technology This driver is capable of amplifying a PWM signal with frequencies up to 100 kHz and is capable of switching the MOSFETs The LT1160 is an IC that has 24 pins it allows two separate non synchronous PWM inputs on pins 2 and 3 The MOSFETs are controlled from pins 9 and 13 The IC can handle source voltage between 10V and 15V which is connected to pins 1 and 10 Figure 3 21 shows a typical set up for this half bridge driver Two of them will be needed to make a full bridge driver 33 1N4148 HV 60V MAX ELL 1000uF E 100V IRFZz44 gt 12V T UVOUT T SOURCE LT1160 L PWM Mnr IN TOP B GATE DR IN TOP IN BOTTOM T GATE DR B GATE DR Pee LPL INBOTTOM B GATE FB L L L L SGND PGND L H H gt H L H L H H L L Figure 3 25 LT1160 Half Bridge Driver Permission Pending from Linear Technologies 3 6 6 Linear Regulator Once the AC signal from the wind generator has been rectified to a DC signal the output voltage from the rectifier still need to be regulated in order to charge the DC battery bank While a constant DC voltage is a requirement to charge the batteries other factors such as charging current and voltage must be adhered to To operate outside these specifications could damage the batteries and reduce their performance and life span Voltage regulation will also be a necessity for other aspects of this design to include microcontrollers LCDs among o
9. and TTL serial peripherals among others Also Visual Studio as IDE chosen is proprietary software but full license is available and ready to be used which will take the topic off the discussion The community support for microcontroller implementations using Netduino development board is very large and consistently updated shorting the learning curve at time of implement dedicated algorithms needed for IRPS There are several built libraries concerning sensors motors LEDs communication tutorials etc are readily available on the Netduino website Finally IDE software would be the Microsoft Visual Studio 2010 and NET Micro Framework SDK 4 1 is going to be downloaded from Netduino website in order to override the AT91SAM7X512 to load and interpret the C code compiled 4 5 2 Algorithm Implementation Microcontroller will execute specific algorithms which are going to perform IRPS core functions Algorithm order is established based on priority criteria of those components which are more critical if occur a malfunctioning and can propagate a system error if they are not taken care at the right step In below Figure 4 7 is depicted a sequential flow diagram referring to main algorithms or methods to be implemented in the microcontroller 77 Check Temperature Check PV Check Wind Threshold Analysis Charging Procedure System Output Display Status Figure 4 7 Algorithm Implementation Flow Microcontroller
10. but simpler model Power generation from winds usually comes from winds very close to the surface of the earth Winds at higher altitudes are stronger and more consistent Recent years have seen significant advances in technologies meant to generate electricity from high altitude winds 25 3 4 Charge Controllers The main reason a system needs a charge controller is to protect the battery from overcharge and over discharge Systems that have small predictable and continuous loads may be able to operate without a charge controller 26 However solar and wind power are nowhere near being predictable or continuous so the design will need to implement charge controllers to help our batteries charge efficiently and without damaging them As was discussed in earlier parts 22 of this chapter solar disadvantages are when the sun is not out the weather is interfering and the wind is not continuously blowing Implementing an efficient charge controller will allow us to overcome the inherent shortcomings of wind and solar power A correctly operating charge controller will also prevent overcharge or over discharge of the battery regardless of temperature or seasonal change in the load profile which will be another major reason for applying this component into our system There are many different algorithms used for the different types of charge controllers but they all have the same basic parameters The manufacturer will usually give you the
11. collection Wind turbine output voltage is defined as Voying and solar panel as Vosoiar for a better understanding of below explanation First alternative being an apparent union of two renewable energy sources to charge one bank of batteries will need a switch system to control charging cycle It is a fact that both sources output cannot coexist as one unique voltage combined cause of intrinsic nature of energy Then the correct approach here would be to adjust the charging duty cycle ratio of two energy sources to obtain a maximum input to battery bank 1 Notice that no microcontroller unit would be needed to make this alternative works a clear sketch is picture in below Figure 3 34 56 K a Vo_solar Vo_wind rx Switch Battery Bank Figure 3 34 Alternating sources using switch This approach will definitely works based on the solid basis that switch will timely alternate sources allowing batteries being charged through solar panels or wind turbine however the lack of decision making the structure as unchangeable methodology and the drawback of an inefficient performance would lead to not a really competent system and a big waste of possible energy harvested Second alternative under consideration would be based on Mu Kuen Chen proposal where previous charging methodology will be redesigned removing switch component and adding a microcontroller Micr
12. research section electrical components of the project will be chosen for purchasing Table 8 2 below shows a tentative schedule of the design stage The initial design concepts should be presented in the documentation at the end of the fall semester The design process will continue through the first month of the Senior Design II semester 114 J D w 5 Solar Power Wind Power Charge Controllers Micro controllers Sensors Inverters Voltage Regulators Nov 19 Nov 26 Dec 03 Dec 10 Dec 17 Dec 31 Jan 07 Jan 14 Jan 21 Jan 28 Feb 04 Feb 11 Feb 18 Feb 25 Table 8 2 Gantt Chart Depicting Design Timeline During the winter break parts may be purchased for early prototyping in the beginning of spring semester All of the parts except those are necessary for the packaging of the final circuit board and electronics solar panel and wind turbine should be purchased before the first half of February The input of the system can be assembled by using the function generator in the laboratory Table 8 3 shows the timeline of the parts acquisition stage The final board can then be fabricated once the design has been tested and the test results have been verified 115 Parts Acquisition controllers Batteries Inverters Voltage Regulator Packaging
13. then controller box is setup to start charging procedure to respective sub bank otherwise controller 74 box will deviate coming voltage not going to specific sub bank and not allowing inappropriate discharging Second in this phase controller box knows what sub bank is needed of charging what charging mode has been set and voltage coming is greater that sub bank current voltage Hence either the value from Check Temperature or default specification is analyzed joined with sub bank current voltage to determine at what specific charging cycle are appropriate sub bank batteries At this point controller box will send appropriate signal to assigned charge controller informing at what charging mode he will operate Also controller box will stop any voltage deviation to dissipative load Fourth stage or LCD Display will wrap around any variable value or alert to make a custom format message and will interact with LCD device to display final outcome Values to be presented are current IRPS output each sub bank status or charge level and IRPS charging operating mode Notice that if any malfunctioning raises an emergent alert no standard format message would be displayed rather the emergency itself 4 5 Monitoring System Design 4 5 1 Microcontrollers Units The Atmel AT91SAM7X512 microcontroller would be used in IRPS pre loaded with the preference of Netduino boot loader This microcontroller contains the adequate hardware and softwa
14. voltage is greater than the output voltage Also the microcontroller will make the circuit behave like a Boost converter when the output voltage is greater than the input voltage The microcontroller should make the circuit operate in a Buck Boost mode when the input voltage is approximately equal to the output voltage This will make the inductor create a continuous current because of the direct connection between output and input This will prevent the high peak current that is experienced in the classic Buck Boost converter It also minimizes stress on both of the input and output capacitors as well as reducing ripple voltage 32 38 3 6 5 Half Bridge and Full Bridge Drivers Half and Full Bridge drivers can solve the problem posed at the end of section 3 6 4 These are integrated circuits that can come with a microcontroller that will control a DC to DC converter to act as a non inverting Buck Boost converter The microcontroller will drive the PWM signal to turn on and off the switches which in this case will be N channel MOSFET transistors They will be switched at certain frequency and duty cycle A full bridge driver could accomplish this by controlling four different MOSFETs Another way to do this would be to use two identical half bridge drivers each one controlling two MOSFETs This might be the best choice because half bridge drivers are easier to find There are several high voltage half bridge drivers currently being manufactured
15. which is temperature in Florida most time of the year and will be used in the IRPS When the battery is full the hysteresis charge will disconnect the float current in order to reduce stress Batteries should be topping charged every six months so that the voltage level will not be under 2 10V per cell and cause sulfation Open circuit voltage OCV method can provide indication of the battery s state of charge A battery that has 90 percent voltage level at room temperature only needs a brief full charge before use If the voltage drops below 90 percent of charge the battery must be charged to prevent damage The storage temperature is also necessary to be monitored A warm battery highers the voltage slightly and a cold one lowers it It works best to estimate the state of charge to use the OCV method when the battery has been resting for a few hours This is because the battery will be agitated by the charge or discharge resulting in distorting the voltage 64 Chapter 4 Project Hardware and Software Design Details 4 1 Initial Design Architectures and Related Diagrams In the overall system the initial design architecture is shown in Figure 4 1 The wind turbine and solar panels will collect powers and the charge controllers will then adjust the current and voltage going to the batteries to prevent overcharging or over discharging Voltage sensors will be place between the charge controllers and batteries When each of the battery
16. 14 Texas Instruments Full wave rectifier During the positive half of the input voltage cycle both output voltages are positive therefore diode D1 is forward biased and conducting and D2 is reversed biased and cut off The current through D1 and the output resistance produce a positive output voltage During the negative half cycle D1 is cut off and D2 is forward biased or on and the current through the output resistance again produces a positive output voltage 28 31 Another alternative for rectifying input ac signal is the full wave bridge rectifier This circuit which still provides electrical isolation between the input aa powerline and the rectifier output but does not require a center tapped secondary winding However it does use four diodes compared to only two for the regular full wave rectifier circuit During the positive half of the input voltage cycle the voltage across the rectifier input is positive and D1 and D2 are forward biased D3 and D4 are reversed biased and the direction of the current is towards D1 and D2 During the negative half cycle of the input voltage the voltage across the rectifier input is negative and D3 and D4 are forward biased The direction of the current towards D3 and D4 produces the same output voltage polarity as before Since the full wave bridge rectifier is more efficient when delivering converted ac power this will be used for the project Q3 Q2 A J Di j L1 s e al
17. 2 lab manual 40 3 6 6 2 Zener Diode Regulator Another form of linear regulators is the zener diode regulator In this design a zener diode is placed in parallel with the load and a regulating resistor is placed in series with the diode and source voltage Once the current is sufficient to take the zener diode into its breakdown region the diode will maintain a constant voltage across itself Here the output voltage should remain constant even with a varying output load resistance and the ripple input voltage from the rectified AC signal For proper operation of this circuit the power dissipation of the diode must not exceed its rated value meaning when the current in the diode is a minimum the load current is a maximum and the source voltage is a minimum The inverse of this should also hold true The minimum designed current should be greater than the minimum zener diode current which can be estimated to be approximately 1 20 the maximum diode safe operating current With an appropriate zener diode selected for the voltage drop needed for the battery the remaining parameters for the circuit can be calculated with the following equations with Ri the input resistance Vs source voltage Vz zener diode voltage Pz power of the diode and diode and load current respectively R Vz Iz h P max Vz max Iz max L max 20 lt L min Iz max I max V max pr Vz I min Vsmin EE Vz Vs min is 0 9V 0 1 max The zener diode r
18. LM555 timer 4 9 Dump and Diversion Loads Two questions should be kept in mind to determine the size of the dump loads First what the voltage of the generation system will be Second what current at maximum power the wind turbine will produce Once this information is known the calculation can take place Ohm s Law will be applied to the calculation The dump load system needs to be able to dissipate the maximum power of the wind turbine and solar panels used Ohm s law states that the power dissipated is equal to the product of the voltage and the current shown in equation 4 1 The voltage of the batteries charged by the wind turbine and the solar panels will be 12 volt batteries The current at the maximum power is approximately to be 30 amperes In this occasion the voltage of the system is the battery bank voltage which is approximately 14 volt for a fully charged 12 volt battery and the currents of the wind turbine and solar panels are approximately 32 amperes and 5 amperes Equation4 1 Power Voltage x Current Therefore by plugging in the values into the equation the maximum power that will be dumped by the diversion load to be 448 watts for the wind turbine and 70 watts for the solar panels is obtained 12 volt dump load resistors will be used in this project The resistors have an internal resistance rating of 0 73 ohms Therefore the amount of power the resistor will consume can be calculated by applying Ohm s Law one
19. Next voltage value would be fed to chosen capacitor with the only function of attenuate the fluctuation and regulate possible spikes before provide output voltage to microcontroller In below Figure 4 9 voltage sensor circuit is simulated using Multisim as proof of previous explanations and calculations A maximum power of 17 4 has been set in the simulation to act like maximum voltage output to sensor circuit First voltmeter in the simulation display voltage across R as of 4 97 V confirming that circuit first step is stepping down voltage below AT91SAM7X512 maximum voltage tolerance of 5V Second and third voltmeters display the filtered voltages and it is observed that difference is only just 5 mV after the voltage follower Multimeter XMM3 EA Figure 4 9 Voltage sensor circuit worst case simulation Simulated components validate that IRPS worst scenario to be experienced would count to a total of 4 975 V and it is demonstrated that circuit last part or Low pass filter is not affecting voltage value but attenuating the final signal Furthermore it is expected to have a slight different output voltage once sensor is implemented with real components due to internal elements variations however voltage can never exceed the 5 V thresholds otherwise R has to be revised and changed to a different value to obtain a simulated small voltage than 4 97
20. Non Inverting Buck Boost Converter Topology Figure 3 25 LT1160 Half Bridge Driver Figure 3 26 TO 220 Transistor Package Figure 3 27 A Circuit Diagram to Make Linear Voltage Regulator Adjustable Figure 3 28 Zener Diode Regulator with Emitter Follower Figure 3 29 ACS712 Breakout Board Figure 3 30 MAX4172 Pin Configuration Figure 3 31 Typical Application Using CSLA2CD Current Sensor Figure 3 32 TMP36 Functioning Diagram Figure 3 33 DS1624 Functioning Diagram Figure 3 34 Alternating Sources Using Switch 10 15 16 19 21 24 25 26 27 28 29 30 31 31 32 33 34 34 35 36 36 37 37 38 39 40 41 42 47 48 49 51 52 57 xvi Figure 3 35 Microcontroller Alternative to Maximize Efficiency Figure 3 36 Voltage and Current in the three charging Stages Figure 4 1 The Block Diagram of the Overall System Figure 4 2 THE WORKHORSE 250 watt Figure 4 3 Voltage amp Amp vs RPM Figure 4 4 Apollo 550W 12V DC blade configuration Figure 4 5 Overall Controller Box Diagram Figure 4 6 Controller Box Block Functionality Diagram Figure 4 7 Algorithm Implementation Flow Figure 4 8 Voltage Sensor Operational Flow Figure 4 9 Voltage sensor circuit worst case simulation Figure 4 10 Rectified Output to 3 3 V scaling and rectification application Figure 4 11 Universal Power Group UPG UB12180 D5745 Sealed AGM type Lead Acid Battery Figure 4 12 Inverter circuit with a LM555 timer Figu
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22. ON time Q2 and Q4 will both be ON at the same time during the opposite switching cycle called OFF time In other words Q1 and Q3 are both ON when the inductor is getting charged while Q2 and Q4 are OFF When Q2 and Q4 are both ON the inductor is charging the load capacitor while Q1 and Q3 are both OFF 31 This topology is very advantageous to the system being built because it utilizes all the topologies discussed so far However the biggest disadvantage to this topology is the relatively large number of components that are required for its design This will raise production cost and it must be discussed if the advantages outweigh the cost Another disadvantage to this circuit is the large number of switches being used This will twice as large switching losses than that of the Buck or Boost converters This is because of the use of four switches instead of two switches The inductor will also have to be larger in this topology to accommodate for the larger current that must be used in the circuit Furthermore the load capacitor must have a lower equivalent series resistance This is due to the fact that the capacitor will carry the full output current during the PWM ON time and the charge current during the PWM OFF time It seems best to use a four switch DC to DC converter that changes its mode accordingly by observing the input and output voltages A microcontroller can be programed to make the circuit operate as a Buck converter when the input
23. PCB Design One of the most important issues that come into constructing our Renewable Source Controlling System box is the printed circuit board design Printed circuit boards are necessary because it allows all of our integrated circuit chips as well as the Display screens resistors capacitors memory devices and other electronic circuits to be soldered by surface mount technology directly to the PCB Without the surface mounting process everything would have to be manually connected to the board by a soldering iron and the process would take too much time Nowadays PCB s are assembled step by step using computer based programs The software used for these computer programs are great to utilize because they allow for flexibility in board design layout as well as editing in case you make a mistake Sunstone Circuits are chosen to get all the design sources to print our circuit board process http www sunstone com The Sunstone s PCB Design Software PCB123 was downloaded When comparing this software to other existing software available out there this one best suite our needs The software acts as a prototype for the Renewable Source Controlling System so it can refer to it often in case for it needs help Once the detailed design specifications are filled in for the PCB it can be directly ordered from the PCB software Procedure for designing a new printed circuit board using Sunstone s PCB Design Software PCB123 V3 for our Renewable Source Con
24. Power Group UPG UB12180 D5745 Sealed AGM type Lead Acid Battery Permission requested pending The charging algorithm used for this type of battery specified by the Universal Power Group is similar to the lead acid charging algorithm reached in chapter 3 Three stages will be included The bulk charging stage will use up approximately half of the charge time and charge up to 70 percent of the capacity When the voltage of the battery reaches the predetermined voltage lever which is set to be between 14 5 to 14 9 volts varying with the temperature the second stage topping stage begins During this stage the remaining 30 percent of the battery will be charged in around 7 hours When the current of the battery has dropped to 0 3 ampere the battery is considered fully charged Then the third charging stage floating charge begins The voltage is dropped to between 13 6 to 13 8 volts The purpose of this stage is to offset the loss due to self discharge The specifications of the UPG UB12180 D5745 AGM lead acid battery is summarized in table 4 7 Nominal Voltage 12V Nominal Capacity 25 C 20 hr 0 90A 18Ah 10 hr 1 67A 16 74Ah 5 hr 3 06A 15 30Ah 1 hr 10 80A 10 80Ah Approximate Weight 11 9 Ibs 5 4kgs Internal Resistance approx 18mQ Shelf Life 3 6 Cycle Use Initial Current lt 5A Control Voltage 14 5 14 9V Control Voltage 13 6 13 8V Table 4 8 UPG UB12180 D5745 Sealed AGM type Lead Acid Battery Specification 87 4 7
25. Table 8 3 Gantt Chart Depicting Parts Acquisition Timeline The next section is the prototyping stage Table 8 4 shows the tentative schedule for prototyping This stage will begin once the necessary parts have received Tests on each individual part will be conducted before implementing to the circuit design All of the components should work properly by themselves especially the sensors The results from the component testing should match the data from the manuals The packaging of the entire circuit design will not be finalized until the testing results of the module are correct 116 Prototype Inverters Voltage Regulator Packaging controllers Batteries Table 8 4 Gantt Chart Depicting Prototyping Timeline The final stage is the most important stage which is the testing stage The testing process will follow closely to chapter 7 All of the components modules and the complete system will be tested The testing should start when some of the acquired parts are received Testing will occur during the prototyping and it will continue through April Table 8 5 shows the timeline of the testing stage Testing D D 38 25 t s eg 8 B d 35 5 8 s 6 8 No amp Mar 18 Mar 25 Apr 01 Apr 08 Apr 15 Apr 22 Apr 29 Table 8 5 Gantt Chart Depicting Testing Timeline 117 8 2 Bu
26. US market in 2011 up from just 25 a few years ago All things point towards more growth in 2012 although this is clouded by dim prospects for the 2013 market depending on the fate of the PTC 22 So far this year according to the AWEA 2 800 megawatts MW of wind along with 1 400 wind turbines have been installed across the US helping the wind industry reach this fantastic achievement Many of the new installations have come from new projects in Nevada Idaho lowa Hawaii Oklahoma and California Some of the key projects that are going in across six of these states according to the AWEA include Pattern Energy s Spring Valley wind farm 30 miles east of Ely Nevada 151 8 MW Enel Green Power North America s Rocky Ridge wind farm in Oklahoma 148 8 MW enXco s Pacific Wind project in Kern County California 140 MW Utah Associated Municipal Power s Horse Butte project in Idaho 57 6 MW First Wind s Kaheawa Wind II wind farm in Hawaii 21 MW 23 What has occurred in the wind industry with the US reaching that plateau is quite remarkable Consider that between 1981 and 2003 5 GW of wind power was generated That number doubled to 10 GW by 2006 then 25 GW by 2008 and now 50 GW in 2012 Also Nuclear energy was the last new energy technology to reach 50 GW done in the late 1970 s and 1980 s Wind potential is enough to take out coal power plants in the US 50 GW of wind provides the same amount of energy as 44 coal
27. V taking into account the physicals components signal offset 82 Implementation starting at above formula 1 will be repeated when measuring voltage in the wind turbine and batteries R value will change for both cases since V is different depending on their specs then formula 1 must be re calculated entering each set of values and simulation similar to above Figure 4 9 has to be implemented for both cases to ensure that no more than 5 V is coming out from particular case sensor 45 4 2 Current Sensor The Allegro ACS712 current sensor from Allegro Microsystems is the final election from all possible choices to be integrated in IRPS It is very helpful that sensor can measure AC or DC current allowing to be moved from one place to another if needed One main advantage of this election is the fact ACS712 is fully adaptable to custom PCB design which is very desirable Current sensor comes in a variety of configurations and IRPS is decided to use ACS712ELCTR 20A T version ACS712 sensor contains a thick copper conductor and signal traces allowing the sensor handle up to 5 times the overcurrent without tampering against proper functionality At the moment it is devised to use one current sensor to measure final converted IRPS system output to a supposedly electric main line such reading will be displayed in the LCD One sensor will occupied one analog input in the microcontroller A typical application for ACS712 current sensor can be observ
28. a system that the polarity of the output does not matter The other disadvantage is that this circuit will only operate in Buck Boost mode If Buck or Boost mode only is needed in the system this circuit will be of no use Off State Figure 3 23 Inverting Buck Boost Converter OFF State 3 6 4 Non Inverting Buck Boost Converter The non inverting Buck Boost converter will not invert the polarity of the output voltage As a result the circuit topology is much more complex than that of the inverting version The circuit to be analyzed will use four transistors for the active switches They will be used to include both the Buck and Boost topologies thus allowing this circuit to perform as Buck only Boost only or Buck Boost converter The circuit being discussed can be seen in figure 3 20 below Transistor Q1 is placed in between the input source and Q2 The inductor is placed between Q2 and Q3 while Q4 will be placed in between Q3 and the load capacitor 37 Figure 3 24 Non Inverting Buck Boost Converter Topology In Boost only mode Q3 is used as a switching MOSFET while Q4 acts as the diode Q1 is always ON while Q2 is OFF and Q3 and Q4 form the boost switching leg In Buck only mode Q1 is the switching transistor and Q2 will behave as the diode from the Buck topology Q3 will be OFF and Q4 is always ON while Q1 and Q2 act as the buck switching leg In Buck Boost mode Q1 and Q3 are both ON at the same time during the switching cycle or
29. and Imp are the parameters that best express the performance of the solar cells which is called the fill factor The fill factor should be around 80 90 for high efficiency solar cells The ultimate goal is to choose a semi conductor material that has an optimal band gap near the middle of the energy spectrum This will ensure that the panel can collect the highest possible amount of solar radiation that the selected material is capable of obtaining 3 2 4 Photovoltaic Panel Performance Solar cells can be extremely inefficient which was talked about in the previous sections Further research will be needed to examine the other factors that will affect the panel outside of the physics of the semi conductors and ascertain any possible ways to increase the performance of the panels Some of the issues being examined are the electron hole recombination rate temperature effect and the light absorption efficiency The impurity concentration of the polycrystalline silicon will increase the electron hole rate which will result in a decrease of the panel efficiency This is the main reason mono crystalline panels perform better than polycrystalline 14 Temperature is another factor that can negatively affect the performance of the solar panel Contrary to popular belief the efficiency of the solar panel decreases as the temperature increases 14 This occurs because the magnitude of the electric field at the p n junction is reduced due to the temperatu
30. b pme 10 km satelite modeled dataset SUNY NREL 2007 representing data from 1996 2005 aang as ie KOTANA ob 2 a Gpo yO the Nasonat Reeantie Enepy Casoraiory Climatological Solar Radiation Model NREL forme US Deparment e E Figure 3 3 Annual Solar Radiation of the United States with permission from NREL There are many different methods to optimize the solar radiation collected by the solar panel Some of those methods include preprogramed angles for each hour of daylight solar tracking light concentration and MPPT Maximum Power Point Tracking The first method is exactly how it sounds The solar panel is mounted on a double axis mechanism and is moved to pre determined angles for each hour of day light Solar tracking also requires the solar panel to be mounted on a double axis mechanism with its movement controlled by the sun s intensity The light concentration implements mirrors or lenses around the panel to intensify the light s concentration The MPPT system is a more indirect approach that controls the photovoltaic output voltage and current to optimize the efficiency An example would be if the battery requires a larger voltage the MPPT system will recognize this and increase the output voltage while decreasing the output current to maintain the same photovoltaic power level 16 3 3 Wind Power 3 3 1 Advantages and Limitations Wind power is a natural resource that is free unlimited and renewable Well designed
31. blades spin a shaft that is linked to a generator that creates the electricity When the wind blows the blades create a lift similar to the wings of airplanes and the blades begin to rotate When the blades rotate a low speed shaft is spanned 30 to 60 times in a minute This low speed shaft is connected with a gearbox or a high speed shaft that accelerates the rotation to 1000 to 1800 rotation in a minute The high speed shaft drives the generator and produces electricity The generator is then connected to an electric power grid Generating the Power Four factors determining the electricity capacity of a wind turbine is wind velocity tower height air density and blade radius Wind velocity determines energy generated Wind is never even sometimes strong and other times weak However wind turbines do not operate in too strong or weak winds If the speed is too low for example below 8 miles per hour the turbines will not work The ideal speed is winds in the range of 25 to 55 mph If the wind goes above 55mph the turbine is switched off as damage can be caused A tall turbine is usually more efficient There are two reasons for this being that more winds can be captured at higher altitudes and there is less turbulence winds are more constant Air density determines the kinetic energy of winds The more dense the winds the more capacity do they have to propel the turbine to turn In high altitudes the air pressure is lower in oth
32. board to be neat and well organized e Another aspect about a snap grid is that it will make editing movement of tracks and components easier to do because the board will eventually expand in size e There are two types of grids in a PCB package that a developer in electronics can choose from a visible grid or a snap grid 4 7 1 Design Equations for Printed Circuit Boards The first design factor for printed circuit boards to discuss about is the conductor capacitance The conductor capacitance is necessary because it will tell the designer how much electrical energy is stored for a given potential Finding the capacitance is easy to figure out once you are given the thickness of the conductor the conductor width and the distance between conductors To attain the value of the dielectric constant for the substrate that can be looked up ina table with other materials Conductor Capacitance d distance between conductors inches b conductor width inches C Q V k substrate dielectric constant a thickness of the conductor inches 90 Another concept that is prevalent in printed circuit board design for manufacturers is conductor resistance Conductor resistance is affected by the thickness of a wire length temperature and the conductivity of the base material being used The thickness of the wire is basically the cross sectional area of the substance being fabricated Area in this case is length of the material times the
33. denote critical system errors status and action to take upon it Finally green boxes and arrows are meant to define successful checking of some components correct availability Once system is ready to be functional it will reach the symbolic step of System Start After this point controller box will begin its pre defined flow checking all required sensors As first stage controller box will enter in Check Batteries mode where a single request will be made to each battery bank voltage sensor an existent battery bank status will be taken into account At the same time both PV and Wind Turbine voltage sensor will be requested to measure actual energy sources output In the same line controller box will request the value of environment temperature sensor on Check Temperature mode which value is highly valuable for further stages If controller box fails on getting previous value into the system then predefined limits will be established by default to not stop 73 IRPS flow It is noticed that IRPS will not perform at its best efficiency at later stages if no actual temperature is obtained however default values will enable that IRPS to continue rather than stop all processes As last step in the first stage controller box will retrieve IRPS actual output using a current sensor when is in the System Output mode value is marked to be displayed later Second stage will be composed of two main modes Thre
34. diagram Permission pending from Adafruit TMP36 measure the temperature using an effortless method where left pin is connected to power 2 7 5 5V right pin to ground and the middle pin will output the analog voltage linearly proportional to the current temperature 44 In order to obtain the current temperature in Celsius grades below formula is used 50 Temp in C Vout in mV 500 10 So as an example if the voltage out is 2V that means that the temperature is 2000mV 500 10 150 C Taking into account that sensor cost is 2 each at Adafruit store and IRPS will need two the total cost of this alternative would be only 4 The only drawback found until here is that two sensors TMP36 will occupied two analog pins in the microcontroller and it is very critical for IRPS design 3 9 3 2 DS1624 Temperature Sensor DS1624 is a Maxim digital thermometer sensor that is very effortless to use as well DS1624 is well designed to be fully integrated directly with microcontroller without the need of using other external components This sensor use C bus as method of communication with microcontroller which is a very advantageous feature to have Briefly J7C bus permits multiple devices to be connected to a single bus excluding the situation of having to use multiple analog pins in the microcontroller However it is noticed that a maximum of eight DS1624 can be connected to IC bus In this case the pins serving temperature sen
35. fire power plants or 11 nuclear power plants The future potential to move at a lightning fast pace and replace these sunset energy sources is very realistic especially when you consider that 39 states now have utility sized wind farms according to the AWEA 20 AMERICA s PRODUCED 50 GIGAWATTS TOTAL U S WIND POWER CAPACITY POWERING THE EQUIVALENT OF 12 8 MILLION HOMES THAT S AS MANY AS NEVADA COLORADO WISCONSIN vrana ALABAMA AND CONNECTICUT COMBINED GENERATING THE POWER OF THE EQUIVALENT OF gt gt 11 NUCLEAR POWER PLANTS COAL FIRED POWER PLANTS 50 GIGAWATTS 50 000 MEGAWATTS 50 000 000 KILOWATTS 50 000 000 000 WATTS Srerdard CFL Uses 13 Wens HHHH A A A A DA DA DAE DE Gaga gqugugqagugzges AWER Figure 3 5 AWEA Infographic In August of 2012 the Energy Department released a new report highlighting strong growth in the U S wind energy market in 2011 increasing the U S share of clean energy and supporting tens of thousands of jobs and underscoring the importance of continued policy support and clean energy tax credits to ensure that the manufacturing and jobs associated with this booming global industry remain in America According to the 2011 Wind Technologies Market Report the United States remained one of the world s largest and fastest growing wind markets in 2011 with wind power representing a remarkable 32 percent of all new electric capacity additions in the United S
36. from draining your battery when the wind is not blowing The assembled wing span of the blades with the hub is 33 to install the unit simply run your charging wires up a 1 i e pipe or conduit and connects the turbine s 2 wire output to your charging wires It produces 6v 120vdc 2450 rpm produces 120vdce direct drive Stall at 120v draws 3 21 A 200 RPM produces over 12VDC The main drawback of this unit is that requires winds higher than 9 miles per hour to start generating power This factor is very important for the project because when both input sources work at least at 60 of its capacity the system needs to be tested If at least half of its capacity is not achieved the batteries will not get charged 68 Figure 4 2 THE WORKHORSE 250 watt Permission Granted from WORKHORSE 2nd option Apollo 550W 12V DC 3 Blades 438 00 http www greenergystar com shop This wind generator will meet our needs for the project The price for this unit is 438 It starts producing energy at 8 mph which is perfect for Orlando whose average wind speed is about 9 2 mph According to the vendor GreenergyStar s Apollo Wind Turbine is the most mechanically advanced generator in the market today It features many upgrades that solve performance issues that our competitors struggle with The following list will summarize its major features With 49 swept area when mounted on a 5 Hub Incorporates highly efficient true airfoil Quiet
37. in below Figure 4 8 y Figure 4 8 Voltage Sensor Operational Flow The voltage across resistor R2 is the voltage that is monitored and measured for the IRPS consequently it will work with electrical specifications of the Solar PV Panel and the microcontroller to prevent any damage or malfunctioning of the system The appropriate resistor values are calculated as following given the conditions R 1MQ R2 Ven 2 Ri R Vp 1 In above formula V represents the voltage drop across R as a function depending of V which represents the voltage generated by the solar panel Solar panel maximum output voltage is 17 4V that number would be taken into account in below formula to find the value of R Vz is the important result here since would be the reading provided to microcontroller and design shown above will enforce that V value won t be ever greater than 5V Taking above formula 1 and maximum voltage value assigned to V5 it is calculated the necessary resistor R value to finish the custom voltage divider circuit R2 V IMA R 17 4V 81 R 403 2kQ 400k0 closest available resistor Having set resistors values voltage divider circuit is prepared to deliver no more than 5V output to microcontroller under current solar panel specs Output from voltage divider will be fed into a voltage follower which is a safety net to separate components in the voltage sensor circuit to avoid interference between them
38. included in the section entitled GNU Free Documentation License This file is licensed under the Creative Commons Attribution Share Alike 3 0 Unported license You are free e to share to copy distribute and transmit the work e to remix to adapt the work CCH Under the following conditions attribution You must attribute the work in the manner specified by the author or licensor but not in any way that suggests that they endorse you or your use of the work e share alike If you alter transform or build upon this work you may distribute the resulting work only under the same or similar license to this one This licensing tag was added to this file as part of the GFDL licensing update HyperPhysics Re Copyrights RMS Ripple Voltage graph Rod Nave rodnave gsu edu You replied on 12 3 2012 9 20 AM Sent Mon 12 3 2012 9 19 AM To Julio F Lara Hello Julio You are welcome to use anything from HyperPhysics for purposes of your academic work Best wishes with the paper Regards Rod Nave RodNave gsu edu HyperPhysics Project Department of Physics and Astronomy Georgia State University Atlanta GA 30302 4106 On Dec 3 2012 at 1 16 AM Julio F Lara wrote Dear Dr Nave I m working on my senior design project and part of the project is the research and documentation of the project found a very good image from HyperPhysics that would like to add to my research paper Woul
39. john den haan nl A A A Actions Wednesday October 31 2012 5 15 AM To Dwade5 knights ucf edu On 29 10 2012 5 47 AM DwadeS knights ucf edu wrote gt Name David Wade gt gt Email Dwade5 knights ucf edu gt gt Message To Whomever this may concern gt gt My name is David Wade and I am a senior EE student at UCF I am building a power generator that utilizes both wind and solar for my senior design project I would like to ask for your permission to use your figure that displays the response of the solar cell to varying temperature for my report Thank you very much for your time and I hope to hear back from you gt No worries these are public domain images American Technical Publishing americantech net right Permissions ie Message Insert Options Format Text Review e B ae Calibri Bod 711 A A F 3 EB oe 0 Ei a Q Ba Copy High Importance Paste a A E ae Address Check Attach Attach Signature Assign Zoom GF Format Painter Biu z s era are Book Names Fie Item X Policyy Low Importance Clipboard FT Basic Text 5 Names Include Tags m Zoom To idh AmericanTech net Subject Copyright Permissions Hello David Holloway PE My name is David Wade and I am an electrical engineering student at UCF I am building a renewable energy power generator that integrates both solar and wind for my senior design project I would like t
40. might consume hundreds of mA while a character LCD would consume less than 100 mA when fully backlit Additionally graphic LCD would introduce more complexity on interaction since it requires not only more programming and testing to make it work but also more I O pins from microcontroller IRPS is not gaining big enhancements from incorporating this element and it is decided to better go to other type of LCD However it is noticed that opting out from graphical LCD will bring as constraint that no touchscreen capability will be offered from IRPS The power consumption was the main reason not to select the graphical LCD however even though the segmented alphanumeric LCD consumes the least amount of power it does a poor flexibility for IRPS and is therefore eliminated as well The 14 segment characters are generally very large per character and do not allow the system to display detailed messages which is very desirable for IRPS performance feedback The segmented LCD option was deemed inefficient because it could not display several status values such as current and voltage simultaneously With not so many discussed alternatives left it is clear that a character LCD screen would be the more suitable solution for IRPS It provides the adequate balance of power consumption and image size quality making it the most viable option As it was discussed on the research portion backlighting is still a necessary feature to be part of the LCD so that the s
41. most cases though the rectifier is supplied as a separate component that must be installed between the wind turbine and the battery charger Often the rectifier is combined with a charge controller into one complete wind turbine control unit Rectification is the process of converting an alternating AC voltage into one that is limited to one polarity The diode is useful for this function because of its nonlinear characteristics that is current exists for one voltage polarity but is essentially zero for the opposite polarity Rectification is classified as half wave or full wave with half wave being the simpler and full wave is being more efficient 30 Sine wave Half wave rectified Full wave rectified Figure 3 13 Rectified Sine Wave Permission Pending The full wave rectifier inverts the negative portions of the sine wave so that a unipolar output signal is generated during both halves of the input sinusoid The input of the rectifier consist of a power transformer in which the input varies from O to 15 volts rms and 0 to 60Hz AC signal and the two outputs are from a center tapped secondary winding that provides equal voltage When the input voltage is positive both output signals voltages are also positive The input power transformer also provides electrical isolation between the power line circuit and the electronic circuit to be biased by the rectifier This isolation reduces the risk of electrical shock Figure 3
42. or 0 062 inches For our design which should use 0 062 inches as it is most recommended And the copper weight is the next factor in the development of the printed circuit board There are two alternatives to select from for the type of copper weight that you want the 1 oz or the 2 5 oz The Renewable Source Controlling System will want a 1 0z to make the finished product for our PCB 62 2 The common standard that is referred to for the design of PCB s is IPC 2221A IPC stands for the Institute for Interconnecting and Packaging Electronic Circuits which is the authoritative figure that controls every aspect of PCB design manufacturing and testing The key document that describes PCB design is IPC 2221 which is specifically titled Generic Standard on Printed Board Design When fabricating the PCB the rules that must be considered when making the foundation for every component being surface mounted on entails board size tracks trace width and spacing pad sizes holes sizes and hole spacing You may ask yourself what are the factors that involve picking an accurate board size track for your PCB These parameters depend upon the electrical requirements of the Renewable Source Controlling System design the routing clearance and space available and your own preference Standard board spacing for routing is 0 3 inches with an additional 1 to 2 inch border on the board for processing Larger track width is preferred more because
43. power and peak power are just two points on a power curve Typically the peak power of a small wind generator is greater than its rated power For example the rated power of THE WORKHORSE 250 is 250 watts at 15 mph Yet its peak power is nearly 400 watts at 33 mph Similarly the Apollo 550W 12V DC is rated at 550 watts but the manufacturer says it will produce up to 800 watts To measure the wind speed it will be used an anemometer which will have to be placed below the wind generator If the anemometer is in the wake of the tower the anemometer will see less wind than the wind generator This will tend to boost the relative performance of the wind generator in the manufacturer s favor For example if the anemometer sees 9 mph but 10 mph winds strike the rotor the wind generator will produce proportionally more electricity than it would at 9 mph The recording system will log production from actual winds of 10 mph in the loggers 9 mph register The power curve will appear better than it really is Standard test procedures call for erecting an anemometer mast separate from and upwind of the wind generator The intent is to place the anemometer in the free stream just upwind of the wind generator s rotor The American Wind Energy Associations or as well known as AWEA has a standard to place the anemometers to measure wind generator s speed Their standard is to place the anemometer 1 5 to 6 rotor diameters upwind of the wind generator rotor s ce
44. power consumption A high level language to be programmed similar to C C Sufficient memory 16K of flash memory Enough amount of analog I O ports JTAG debugging Convenient software libraries IDE Processor speed exceeding our routines tasks Practical to be integrated with external peripherals Wireless data logging LCD Good community support is not mandatory but desirable e Good sleep mode when it is not in use 3 10 1 Atmel ATmega328 The option of ATmega328 from Atmel is a microcontroller featuring 14 digitals I O pins 6 of them PWM outputs 6 analog inputs 32k flash memory and 16 MHz 52 clock speed Since the Atmega328 microcontroller could be pre loaded in the development board Arduino Uno R3 it can be programmed using the Arduino language which is similar to C 40 The microcontroller on the board is programmed using the Arduino programming language based on Wiring and the Arduino development environment based on Processing 41 The Arduino board can be powered using 5V USB port or an external DC power line 7V 12V and chip by itself consume 5V DC At the same time the board is capable to provide 5V and 3 3V DC output to feed sensors or others low power components Ability of outputting some power is vital to test ATmega328 working in conjunction with sensors during the development phase Arduino language and IDE are protected under the open source copyright which means if ATmega328 microcontroller is selec
45. that the reason of having some components forming part of controller box concept doesn t mean that they will be physical located next to microcontroller in the prototype implementation Rather controller box encapsulate them as grouping similar actions to easily explain most of IRPS actions Being controller box one important part of IRPS circuitry but not the whole board several electrical components are left out of its design and they are detailed in their own design section Controller box concept encompassed the microcontroller voltage sensors current sensor temperature sensor LCD display and a USB interface An overall design of controller box is described in below Figure 4 5 71 poo we6oid peog Voltage Sensor AKo Current Controller Sensor Voltage Sensor Voltage Sensor Voltage Sensor Figure 4 5 Overall Controller Box Diagram First and more important component as core of controller box is the microcontroller depicted as the dark grey box in the middle of Figure 4 5 microcontroller chosen was the Atmel AT91SAM7X512 with Netduino boot loader Orange box at the top left of diagram is describing the temperature sensor to be used in the IRPS temperature sensor chosen is DS1624 and will use microcontroller C bus to provide actual readings Light blue boxes are referring to voltage sensors in IRPS where each one of them will consume one analog input of microcontroller Light green bo
46. the input source The Boost converter has two distinct 35 stages it operates in Below is a figure of a Boost converter that will be used in the description of the three different stages Figure 3 20 Schematic of a General Boost Converter with permission from Creative Commons The first stage the switch is closed and the diode is off the current runs in a clockwise direction During this stage the inductor is charging and acquiring energy The switch short circuits and effectively disables the RC part of the circuit Since the diode is off it will prevent the capacitor from charging 30 During the second stage the switch opens and the diode turns on This will make the impedance higher thus causing the current to slow down The inductor will try to resist this change and it will cause the current to move in the opposite direction This will cause to act like a source which in turn makes the capacitor charge due to the two sources which are in series input source and inductor As a result the output voltage will increase as the current decreases 30 3 6 3 Inverting Buck Boost Converter The inverting Buck Boost Converter is as the name implies a mixture of both the Buck and Boost topologies This converter uses the same components as the converters described above The inductor is placed in parallel with the load capacitor the switch is in between the source and the inductor and the diode is placed between the inductor and the loa
47. the same amount of power as its silicon competitors This is the main reason thin film technology has not replaced the silicon technology The efficiency has not quite matured yet but it could surpass the efficiency of the silicon panels by 2020 11 As exciting as this new technology is it will be difficult to implement it in this project at its current efficiency level The silicon panels will be needed for more testing due to the inherent inefficiencies of thin film technology 3 2 2 4 Copper Indium Gallium de Selenide CIGS Thin Film Copper Indium Gallium Selenide or CIGS is another type of thin film semiconductor material CIGS is a material that strongly absorbs sunlight thus requiring a much thinner film than other semiconductor materials CIGS absorption coefficient 10 cm for 1 5 eV is higher than any other semiconductor used for solar panels CIGS is mainly used in the form of polycrystalline thin films and the best efficiency was achieved in December of 2005 at 19 5 17 Higher efficiencies around 30 can be achieved with the use optics to concentrate the sunlight onto the panels The market grew for this PV at a 60 annual rate from 2002 to 2007 16 Like other thin film panels the CIGS compound is layered on a glass back plate Since so little of the material is needed the CIGS thin film panels are extremely light weight Due to the ever increasing efficiency associated with CIGS panels their production is projected to increase r
48. they have low direct current resistance and relatively small inductance Lower limit of the track width will depend upon the track resolution that the manufacturer for the printed circuit board is capable of producing Also the size of the board will have a particular amount of resistance given off Finally the thickness of the copper substrate will have a huge effect on the printed circuit board when soldered upon 103 Pads are defined as a portion of a pattern on PCB s that are selected for the purpose of surface mounting electrical components The important topics concerning pads involve their sizes shapes and dimensions Pads heavily rely upon the manufacturing process used to make the printed circuit board as well as a person s solder ability Another factor that is used to evaluate pads on a PCB is known as the pad or hole ratio More generally the pad or hole ratio is referring to the pad size to hole size The rule of thumb for the pad on the PCB should be 1 8 times the diameter of the hole because it will let the alignment tolerances on the drill Using the PCB 123 software the manufacturer has the option of choosing which whole sizes he prefers best to implement on the printed circuit board Make sure to notice that when picking a hole size the plate through will directly result in making a hole narrow These plate through thickness of the holes range from 0 001 inches to 0 003 inches Another design rule to consider when making a PCB is t
49. this type as much No one semi conductor has a band gap that can respond to the full range of the sun s light 13 Solar panels have been invented that can respond to the full spectrum of the sun s light by layering different types of semi conductors with different band gaps in series 13 However the manufacturing process of these panels is extremely difficult and expensive therefore they are not readily available to the consumer market The solar panels which are in the consumer market are usually made up of one or two types of semi conductors which can have their band gaps modified by different doping techniques 12 When the photons hit the solar cells the semi conductors will absorb the photons that have energy equal to or greater than that of the band gap This promotes electrons in the conduction band which is how energy is produced in the cell If the photon s energy far exceeds the band gap the energy will be dissipated off as heat and if the energy is much smaller the photon will just pass through the solar panel and no energy will be collected from it 12 Obviously the goal of the solar panel is to produce power so the solar panel needs to create current and voltage from the photons to make power 13 There are two important parameters for both the current and the voltage The current has lsc short circuit current and Imp maximum power current the voltage has Voc open circuit voltage and Vmp maximum power voltage Vip
50. to the control box The LCD screens will display the current live metrics of the system to users as feedback Chapter 2 Project Description 2 1 Motivation and Goals A common interest in power electronics and power systems was the initial motivation that directs the group to develop this project of designing a power system controller Moreover inspired by the fast development of innovative technologies the group aim to advance with times and apply what was learned in class with real life problems Additionally as world population grows the shortage of resources increases dramatically The consumption of power and energy increases as well To conduct a research on renewable energy becomes appealing more than ever Renewable energy sources are those have no undesired consequences during the process of power production All of them have lower carbon emissions comparing to conventional energy sources Among those renewable energy sources wind and solar are considered the most environmental friendly forms of energy However due to the unstable and uncontrollable nature of wind and solar resource relying on either source solely may not be sufficient to make a stable and consistent power supply system Consequently the power consumption of solar and wind energy are the lowest among all of the renewable energy for the past decade illustrated in Figure 2 1 In order to increase the consumption of solar and wind energy a much more stable consi
51. use VDC the ac signal produced by the wind generator will have to be rectified To do this is going to be added an AC DC rectifier to the ac line to produce a rippled dc signal Although system can technically use this rectified dc signal it is still needed to regulate it in case that wind generator produces more power that is expected to In order to maintain VDC at a voltage suitable to charge the batteries without over passing the max battery voltage it is going to be added a voltage regulator to the rectifier output line this voltage regulator circuit will maintain the voltage at a maximum of 15VDC Once IRPS have the refined DC from the wind generator it will be connected both PV panels and wind generator to the controller box Within this box the microcontroller voltage sensors current sensor temperature sensor LCD display and USB interface will be located The microcontroller will determine which input source is the most productive when both sources are in operation to do this it is placed a voltage sensor in each source line to determine which input is the higher This will help the charging system to choose the input source with greater power to maximize the charging system Once the batteries are fully charged the microcontroller will have to divert the excess power to a dump load The load is usually an electrical load which is drawing electricity that is generated by the solar panel or the wind turbine The final stage of IRPS
52. wave Since household electronics will be plugged into this systems output the output voltage will not need to be a perfect sine wave but it cannot be a square wave either A square wave could damage the appliances that have been plugged in so a mid quality invertor will need to be purchased or some filters will be required to clean up the output waveform These are the four main factors to consider for purchasing a manufactured DC to AC invertor Several different brands will be compared later and the most appropriate model that fits the budget will get be picked 3 8 1 Inverter Efficiency By efficiency the real meaning is what percentage of the power that goes into the inverter comes out as usable AC current nothing is ever 100 efficient there will always be some losses in the system This efficiency figure will vary according to how much power is being used at the time with the efficiency generally being greater when more power is used Efficiency may vary from something just over 50 when a trickle of power is being used to something over 90 when the output is approaching the inverters rated output An inverter will use some power from the batteries even when there is not any component drawing any AC power from it This results in the low efficiencies at low power levels A 3Kw inverter may typically draw around 20 watts from the batteries when no AC current is being used It would then follow that if you are using 20 watts of AC pow
53. width of the material In order to determine the conductor resistance the only specification that a designer needs to take into consideration is the conductor width Conductor Resistance W conductor width inch The characteristic impedance of an electric structure is the ratio of amplitudes of voltage and current waves moving along an infinitely long line Characteristic impedance comes into view as resistance due to them having the same SI units The power of the infinitely long line is accounted for since it is being generated on one end of the line and transmitted through the line as well For a printed circuit board this is the formula used to determine the characteristic impedance of an infinitely long line Characteristic Impedance C capacitance F L inductance H Zo impedance Q R resistance Q G conductivity per unit length of line Q 1 A microstrip is an electric medium that can be made using a PCB The cross sectional surface representation of a microstrip can be divided up into 4 components These components are the conductor the upper dielectric dielectric substrate and the ground plane Some drawbacks to the microstrip are that they have minimal power handling capacity and high losses A is known as the top conductor B is the upper dielectric medium C is defined as the dielectric substrate or level between the dielectric and the conductor D is referred to as the ground plane Illustrated below is
54. 3 9 Sensors 3 9 1 Voltage Sensors For our project is crucial to monitor input voltage coming from renewable sources and battery bank to display corresponding values to LCD screen Microcontroller unit will be constantly receiving voltage and analyzing such reading processing accordingly and sending it out to external LCD screen However if this is just implemented straight out the box it is going to be discovered that microcontroller could be potentially damaged due to overcoming maximum voltage specification Most microcontrollers have a more reasonable 5V tolerance and taking voltage directly from sources will peak over microcontroller threshold and cause system to overheat and fail In order to manage the voltage reading a voltage sensor will be placed before our microcontroller analog input and as it name indicates this sensor will be responsible to calculate and step down maximum voltage to a more reasonable range below 5V Sensor will be placed in parallel with PV panel voltage output acting as a voltage divider to not interfere with reading coming into Voltage Regulator Complete configuration would be two resistors R1 and R2 connected in series and their value will be determined based on solar panel maximum power Essentially R1 would have a higher resistance value to guarantee not having high flows of current passing to microcontroller port Furthermore voltage after R2 let s designated V2 would be the safe output voltage to be analy
55. 48 watts of power Two of the WindyNation 0 73 ohm resistors wired in parallel will give a total dump load capacity of 536 watts According to the user manual to protect the expensive wind generator battery bank and alternative energy system from potential destruction it is necessary to choose a dump load that exceeds the maximum output of your complete system by at least 20 percent Use the equation below to calculate the exceed power percentage two parallel WindyNation 0 73 ohm resistors can consume about 19 6 percent more power than the maximum output of the complete system 51 Equation 4 4 power consumed by the dump load maximum output of the complete system maximum output of the complete system 94 Resistor Resistor Figure 4 13 Two Dump Load Resistors Connected in Parallel Similarly the same process can be applied to calculate the dump load for the solar system Since the 0 73 ohm dump load resistors can consume 268 watts of power and the capacity of the dump load needed is only 70 watts one WindyNation 0 73 ohm resistors will be sufficient for the design 95 Chapter 5 Design Summary of Hardware and Software 5 1 Hardware Summary To summarize the hardware design of the Renewable Source Controlling System it is first described the essential elements that will generate power As input power source would be used 12VDC 85W PV panels and 15VAC 450W wind generators Since the battery charging system will only
56. 65 4 2 1 Mounting 67 4 3 Wind Power Generation 68 4 4 Controller Box 71 4 5 Monitoring System Design 15 4 5 1 Microcontrollers Units 75 4 5 2 Algorithm Implementation 77 4 5 3 LCD Display 80 4 5 4 Sensor Implementation 81 4 5 4 1 Voltage Sensor 81 4 5 4 2 Current Sensor 83 4 5 4 3 Temperature Sensor 84 4 6 Battery Bank 85 4 7 PCB Design 88 4 7 1 Design Equations for Printed Circuit Boards 90 4 8 DC AC Inverters 92 4 9 Dump and Diversion Loads 93 5 0 Design Summary of Hardware and Software 96 5 1 Hardware Summary 96 5 2 Software Summary 96 6 0 Project Prototype Construction Plan 101 7 0 Project Prototype Testing 103 7 1 Solar Testing 103 7 2 Wind Testing 104 7 3 Microcontrollers and PCB testing 106 7 4 Sensor Testing 107 7 5 Integrating Solar and Wind Generation Testing 109 7 6 Storage Testing 110 7 7 Wind Generator Rectifier Testing 111 7 8 Voltage Regulator Testing 112 7 9 DC AC inverting and Power Output Testing 112 7 10 Dump and Diversion Load Testing 113 8 0 Administrative Content 114 8 1 Milestone Discussion 114 8 2 Budget and Finance Discussion 118 8 2 1 Budget 118 8 2 2 Finance Discussion 8 2 2 1 Final Client Price 8 2 2 2 Analysis of Profitability Appendices Appendix A References Appendix B Copyright Permissions Appendix C Figures Appendix D Tables 119 121 123 xvi xviii Chapter 1 Executive Summary As the demand of renewable energy increases solar and wind have become more a
57. DC AC inverter is defective or not Verify the batteries are not connected when measuring system Connect converter to variable DC power supply and multimeter Double check connections of circuitry and equipment Power on variable DC power supply and multimeter Vary power supply through expected AC voltage range Check circuit for temperature Measure and record AC output throughout range of inputs Power off equipment before disconnecting The efficiency of a voltage regulator defines the percentage of power that is delivered to the load and is given by f Pout i Efficiency Pin 100 7 10 Dump and Diversion Load Testing Two scenarios should be considered with respect to testing the dump and diversion load First scenario is to test if the dump load resistors work properly solely without connecting to the system when expected output power of the solar panel and wind turbine are applied The voltage across the dump load resistors and current going through them should be measured by using multi meters The power that the dump load resistors dissipate should match the calculated result from section 4 11 Each set of the load resistors will be tested for both the wind power generation and solar power generation The second scenario is to test if the dump load resistors work properly when connecting to the system When the battery is charging there should be no current going to the dump load resistors The dump load is expected to be disconnec
58. DEPARTMENT OF ELECTRICAL amp COMPUTER ENGINEERING UNIVERSITY OF CENTRAL FLORIDA EEL 4914 Senior Design I Integrated Renewable Power System Controller Group 28 Karel Castex Julio Lara David Wade Jing Zou Sponsored by Progress Energy Table of Content 1 0 Executive Summary 2 0 Project Description 2 1 Motivation and Goals 2 2 Objectives 2 2 1 Small Scaled 2 2 2 Self Sustained 2 2 3 Efficiency 2 2 4 Environmentally Friendly 2 2 5 Low Maintence and User Friendly 2 2 6 Input 1 Solar Power 2 2 7 Input 2 Wind Power 2 2 8 Control Box 2 2 9 Energy Storage 2 2 10 Output 2 3 Project Requirements and Specifications 3 0 Research 3 1 Related Projects 3 2 Solar Power 3 2 1 Advantages and Limitations 3 2 2 Solar Cells and Manufacturing Technology 3 2 2 1 Mono Crystalline Silicon 3 2 2 2 Polycrystalline Silicon 3 2 2 3 Thin Film and Amorphous Silicon 3 2 2 4 Copper Indium Gallium de Selenide CIGS 3 3 2 5 Cadmium Telluride CdTe Thin Film Panel 3 2 2 6 Gallium Arsenide GaAs Thin Film Panel 3 2 3 Photovoltaic Effect in Solar Cells 3 2 4 Photovoltaic Panel Performance 3 2 5 Solar Radiation 3 3 Wind Power 3 3 1 Advantages and Limitations 3 3 2 Wind Power Mechanism 3 3 3 Wind power Performance 3 3 4 Capacity and production 3 3 5 Distribution of Wind Speed 3 4 Charge Controllers 3 4 1 Shunt Controller 3 4 2 Series Controller 3 4 3 Maximum Power Point Tracking MPPT o ooon A A BRWWWWWOND 3 4 3 1 Perturb and O
59. Figure 3 15 Texas Instruments Full Bridge Controller As the voltage runs through the diodes it becomes a form of DC voltage along with pulsations of up and downs which is called as ripple voltage For this project the charging circuit requires a steady state DC input free from ripple voltage A RC circuit can be added that soothes out these ripples and improve quality of rectified output 32 Capacitor discharge Y Vprume t RC coe Cin te pee Votind o lt Vida ODD a ne de 120 RC 4 A i Pay ws Y ripp For a sinusoidal voltage you s pi i de pin would obtain the rms from y ri 2 the peal to peg kb y 1 r f TORRET me p find T dividing by 2andthen by f i N Vde pfin qD But this waveform y f i i ORC more closely h H A J A an 75 approximates a af 7 Vv de Vv pin J sawtooth wawe for p x i 240 R which the rms factor if isal z leading to Fi E for T 1 120 sec elascadedwadves once BOs Se de soln os NRE ETE L y piny tai 3 gt Yrirms 240 3RC for small ripple tdis T Figure 3 16 RMS Ripple Voltage 3 6 Voltage Regulator DC DC Converter Voltage regulators or DC to DC converters are necessary because the DC voltage coming off the solar panels are not a constant throughout the day Also in order to optimally charge a battery the input voltage must be regulated because the battery voltage will change
60. LP technology to sleep when current is at low as 20nA 42 Research over this microcontroller family yielded that Microchip offers a vast package of documentation libraries examples tutorial datasheet and diagrams about how to use and interact with this microcontroller Having those elements at hand will ease any development that could take effect over PIC24F Downside of previous advantages is that a complete development board along with MPLAB IDE comes to the price around 70 based on Microchip website Even though IDE itself is given at free charge by Microchip this IDE is completely based on some proprietary C compiler which license must be purchased Final price is not discouraging the possible decision of using PIC24 family because microcontroller comes with a good variety of ports speed and desirable characteristics and not to mention that is flexible to integrate in a PCB solution 54 3 11 LCD Display Our integrated energy harvested system would ease the output reading if only one LCD display is used to combine all metrics there Therefore our aim regarding output display is targeting toward having a low cost low power consumption LCD device capable of showing all reading in one place including the batteries status In order to do so our searching will be focus to acquire a LCD with more than 4 lines and suited to hold up to 20 characters per line that space would be enough to exposure all sensors reading plus battery checkin
61. NASA SSE website n d http eosweb larc nasa gov sse 55 Wind Powering America n d http geocommons com maps 67683 56 www eia gov electricity sales_revenue_price xls 57 Godfrey E February 24th 2012 What is a Cost Plus Pricing Strategy http smallbusiness yahoo com advisor cost plus pricing strategy 120017163 html 58 ENERGY STAR Building Manual July 2007 Chapter 3 Investment Analysis Adobe Digital Edition Version 59 U S Department of Energy January 2012 Rulemaking overview and preliminary market and technology assessment energy efficiency program for consumer products Set top Boxes and Network Equipment Adobe Digital Edition Version 60 Database of States Incentives for Renewable amp Efficiency DSIRE 2012 Financial Incentives http www dsireusa org incentives 61 EnergyBible Com 2012 Solar Panel Manufacturers http energybible com solar_energy Solar 20Manufacturers html 62 http www sunstone com 63 http www smps us pcb design html 64 http www radio electronics com info electronics design pcb pcb design layout guidelines php Appendix B Copyright Permissions eia gov Figure Permission jingzou Sent Tue 10 23 2012 2 15 PM To infoctr eia gov Hello EIA am in an electrical engineering senior design class at the University of Central Florida in Orlando FL am currently working on creating an integrated renewable power system controller for my senior desig
62. PS temperature sensor chosen is DS1624 and will use microcontroller 72C bus to provide actual readings Light blue boxes are referring to voltage sensors in IRPS where each one of them will consume one analog input of microcontroller Light green box is ACS712 current sensor from Allegro which is going to be placed at IRPS output line Dark green rectangle is representing the LCD display which is going to display every important reading produced from microcontroller and any last time message or alert LCD screen will be communicated with microcontroller through serial communication or more specific TX and RX microcontroller pins An usb interface will interact with microcontroller allowing updating program code usb interface will be represented by a USB to TTL integrated circuit 97 Controller box possess a pre defined block diagram of how logically will perform as a whole An overall controller box block diagram is described in below Figure 5 2 H Sy Check Check Batteries Temperature System Output ee 7 Sensors Threshold Algorithm Storage Bank Charging Procedure LCD Display Figure 5 2 Controller Box Block Functionality Diagram Controller box functionality diagram is shown in above Figure 5 2 and it is divided by using symbolical colors Blue boxes and arrows means logical stages and system direction flow Light oranges boxes are used to describe physical components which interact with some stages
63. Project the following Table 8 7 shows the number of PV installations in the United States by year It also shows an approximated number of installations per manufacturer given that there are around 30 major manufacturers of PV systems 61 123 Year Number of Installs Installs Manufacturer 2002 2537 85 2003 3418 114 2004 5223 175 2005 5242 175 2006 8503 2 2007 15785 52 84 7 2010 38262 1276 2011 34352 1146 Table 8 7 PV installations in the United States From above Table 8 7 it is apparent that there is increasing growth in the number of installed PV units Because of incentives such as government tax credits for these systems and increased environmental concern it is expected that this upward growth continues A conservative estimate of the amount of units to be manufactured and sold in the first year would be 1000 units this number is only useful for further estimations The U S Energy Information Administration provides data on the number of PV systems shipped From this data an industry growth rate of 46 34 is projected for the residential sector Overall the average growth rate in the residential sector between 2000 and 2010 is 46 34 Using this rate the number of units sold in subsequent years can be projected as presented in the following table Assuming that material and manufacturing costs do not change costs and revenues can also be projected as it is shown in below Table 8 8
64. V Operating Temperature 25 C 85 C Sensed Current Peak 72A Output Sensitivity 32 7 mV N 3 0 mV N 8 Vdc Output Rise Time 3us Output Type Voltage Table 3 3 CSLA2CD current sensor key characteristics 3 9 3 Temperature Sensors In spite of providing IRPS controller the actual temperature of environment where batteries are located a temperature sensor would be placed on to capture current ambient temperature The aim of this sensor is to be classified as an inexpensive solution which would be easy to integrate to microcontroller analog input port and delivery an accurate reading of temperature under humid conditions One desirable aspect of the temperature sensor to have would be the fact to be easily exchangeable in case of malfunctioning 3 9 3 1 TMP36 Temperature Sensor These types of sensors are very precise since they implement a voltage drop between base and emitter methodology which is very viable This approach overcomes other traditional methods using mercury old thermometers bimetallic strips home thermometers or thermistors temperature sensitive resistors and it is very suitable for IRPS proposed design 44 As a result of not having moving parts TMP36 is very precise don t need calibration never wears out work under stressful environment and it is an inexpensive easy to use alternative The structure of sensor is shown in below Figure 3 32 Ground a a Figure 3 32 TMP36 functioning
65. Workhorse 250 pvc 140870866708 Sent Date Dec 02 12 22 02 46 PST Dear billydan2011 Hi I m working on my senior design project and part of the project is the research and documentation of the project Your item can potentially be acquired for our project For illustration purposes would like to add the picture of your item for the research part of our project Would you please grant me permission to use your image for my project bufalo_jl WIND GENERATOR TURBINE WINDMILL NEW ITEM Workhorse 250 pvc Item Id 140870866708 End time Dec 19 12 03 05 41 PST Seller dillydan2011 295 se 98 8 Positive Feedback Member since May 28 11 in United States Location FL United States Listing Status This message was sent while the listing was active xi Green Energy Star GreenergyStar Grid Tie Inverter Grid Power III 600W For Solar amp Wind Hybrid Systems Your message has been correctly sent GreenergyStar Grid Tie Inverter Grid Power II 600W For Solar amp Wind Hybrid Systems info greenergystar com Sent Mon 12 3 2012 1 08 AM To fbufalo knights ucf edu Your message has been correctly sent to our Customer Service Your message Hi I m working on my senior design project and part of the project is the research and documentation of the project Your item Apollo 550W can potentially be acquired for our project For illustration purposes I would like to add the picture of your item and the Voltag
66. Year Units Sold Cost 3810 80 Revenue Profit 46 34 Growth 4954 40 1 1000 3 810 800 00 4 954 040 00 1 143 240 00 2 1464 5 579 011 20 7 252 714 56 1 673 703 36 3 2143 8 166 544 40 10 616 507 72 2 449 963 32 4 3137 11 954 479 60 15 540 823 48 3 586 343 88 5 4591 17 495 382 80 22 743 997 64 5 248 614 84 Table 8 8 Units sold projection Indeed the NPV of the profit is calculated to demonstrate the worth of the project today using the discount rate of 7 The NPV equals 11 008 420 21 This 124 project s positive NPV shows that large scale IRPS prototype would be worth pursuing 125 Appendices Appendix A Work Cited 1 M Chen The Integrated Operation of Renewable Power System IEEE Canada Electrical Power Conference 314 319 2007 2 http exploringgreentechnology com solar energy advantages and disadvantages of solar energy 3 http www nrdc org energy dirtyfuels_tar asp 4 http www solar facts and advice com monocrystalline html 5 http en wikipedia org wiki File PV_Technology png filelinks 6 Mark Z Jacobson 2009 Review of Solutions to Global Warming Air Pollution and Energy Security p 4 7 Photovoltaic Cell Conversion Efficiency U S Department of Energy Retrieved 17 October 2012 8 Thin Film Cost Reports pvinsights com 2011 last update Retrieved 17 October 2012 9 Georgia Tech SmartTech Search 10 http
67. al The current solar drip feed batteries available are more suited for home use instead of large scale solar power production 2 The final and most important limitation is the cost of installing solar panels There is a large upfront cost and is the equivalent to paying for 30 years worth of power just to install the system 2 However technology will eventually help bring down this cost as it increases and energy subsidies are put in place by governments around the world 3 2 2 Solar Cells and Manufacturing Technology There are many different types of materials used to make solar cells All of them vary in their cost and efficiency characteristics For this project the design will be looking for as high efficiency as can be possibly achieved while staying inside the budget The system will need to charge the batteries as quickly as possible because there are only so many hours of day light each day Solar panels are broken up into two different categories silicon and thin film Silicon has been around and studied much longer making it the more reliable of the two technologies The efficiency of the solar panels by definition is the ratio of electrical output power to the amount of sunlight received The equation for the energy conversion efficiency can be seen below in EQ 3 1 where P in W is the maximum power point E in W m is input light and A in m is the surface area of the panel 7 EQ 3 1 Energy Conversion Efficiency
68. and available capacity of the battery The LVD does not have to be temperature compensated unless the battery is operating below 0 C 26 Similar to the VRH the LVDH is the difference between the LVD set point and voltage at which the load is reconnected to the battery If the LVDH is too small the load will rapidly cycle on and off at low battery state of charge which can damage the controller If the LVDH is too large the load may remain off until the array fully recharges the battery 26 A large LVDH could increase battery health due reduced battery cycling However the availability of the load would be sacrificed All four of the set points described above will have to be analyzed in depth as the charge controller is put through the design phase of the project The set points are crucial to the health of the battery and charge controller 23 3 4 1 Shunt Controller After discussing the basic theory of the charge controller above the methods of actually controlling the charging of the battery should be examined There are two basic methods that could be utilized for this project and they are series and shunt regulation Both of these methods can be highly effective for the charge controller with each having benefits and limitations First the shunt controller method which is tends to be designed for PV systems with currents less than 20A The shunt controller interrupts the current by short circuiting the array to regulate the charging of
69. and compare with coincide thermometer A heat source would be Increased temperature Pending applied to both thermometer reading should be equal in and temperature sensor thermometer and DS1624 Table 7 6 Temperature sensor Testing Plan 7 5 Integrating Solar and Wind Generation Testing This will be the test that proves if the system as a whole is working or not As the system is currently designed there are four distinct modes of operation These modes of operation can be seen below in Table 7 7 The batteries are labeled Esolar for the solar bank and Ewing for the wind bank In the first mode only the solar panel is generating voltage so the microcontroller will switch the solar voltage to charge both Esoiar and Ewing banks The second mode is wind only and the voltage from the turbine will charge both Esoiar and Ewing banks In the third mode the solar panel and the wind turbine are generating voltage however the wind speed is low which will be less than 3 m s In this mode Esolar and Ewina banks will be charged by their respective source The fourth and final mode is the same as mode three but the wind speed is high which will be above 3 m s In this case the Ewing will be charged by the turbine while Esoiar will be charged by both the solar panel and the wind turbine Energy Source Solar Energy Ewind EF olar 1S W o Table 7 7 Microcontroller Alternative Charging Modes Wind Energy Solar and Win
70. ank from overcharging and the solar panel or the wind turbine always operating under an electrical load 34 3 8 DC AC Inverter Many small electronics such as cell phones and I pods can run adequately off of DC voltage which can be generated from a car s cigarette lighter However for this project household type electronics will be powered from the system which tends to require more power This means that AC voltage of the same quality as an electrical outlet will be required to power these appliances This will be the final component of the system allowing it to accomplish the ultimate goal of powering electronics from a battery that has been charged with solar and wind power The main function of the inverter is take 12V DC from the battery and step up the voltage to 120V and convert it to AC voltage which will be delivered through a 3 prong electrical wall outlet This will require high rated cables due to the high amperage coming from the connections A DC to AC invertor can easily be built with a transformer a couple of transistors and some resistors However this project is more concentrated on the control aspect of the whole system so some of the prebuilt DC to AV inverters should be researched There are four main concerns that one should have when shopping the internet for a good DC AC invertor and they are What type of devices are being powered This is a major concern because an inverter with the appropriate wattage will be nee
71. ap engineering which will maximize the amount of light the solar panel is able to absorb The design engineer can choose to create smaller band gaps to capture the lower energy photon However the lower energy light will result in a lower voltage The engineer could increase the band gap to gather more of the higher energy photons but the panel will not absorb the lower energy level photons causing a lower current A balance has of these two different ways of band gap engineering must be found to ensure an optimal solar panel Another thing to remember is that much of the light is lost due to reflection This is why most solar panels will have a layer of anti reflection material on top of them to minimize this negative effect 3 2 5 Solar Radiation Solar radiation is the electromagnetic radiation that is emitted from the sun and is collected by the solar panel to produce power Solar radiation is measure in kilowatt hours per square meter per day kWh m day Figure 3 3 below shows the annual solar radiation of the United States As can be seen in the figure the best location for solar power in the country is the southwestern region with around 7 5 8 0 kWh m day Central Florida averages per year around 5 5 6 0 kWh m day according to the figure below 15 15 Photovoltaic Solar Resource Flat Plate Tilted South at Latitude Annual average solar resource data is shown for a tit g collector The data for Hawaii and the 48 coniuois sias ls
72. apidly in the future Unfortunately these panels tend to be extremely expensive due to their vacuum based fabrication process 17 Therefore CIGS thin film panels will not be considered for the solar panel of the project 3 3 2 5 Cadmium Telluride CdTe Thin Film Panel Cadmium Telluride or CdTe was one of the orginal materials used in thin film technology to try and improve the low efficiencies experienced with amorphous silicon Like CIGS CdTe is also manufactured on a glass substrate CdTe is the most common and the most cost effective type of thin film technology on the market currently Similar to CIGS CdTe panels perform better in the shade and low light conditions than silicon does Unfortunately CdTe panel s efficiency maxed out in 2001 at 16 5 and their average efficiency is around 7 to 12 18 Another disadvantage to the CdTe thin film technology is that Cadmium is extremely toxic and Tellurium supplies are scarce This leads to CdTe panels being exceedingly expensive and toxic to people and the environment 12 3 2 2 6 Gallium Arsenide GaAs Thin Film Panel The final type of solar panel to be discussed in this research is Gallium Arsenide or GaAs thin film panels Like CdTe panels GaAs panels are extremely expensive and toxic Gallium is an extremely rare material and Arsenic is a very poisonous substance People can become very sick and possibly die if the panel gets damaged and the semiconductor is exposed However the efficie
73. arges and discharges allowing the current to go back to the DC source The inverting current direction produces alternating current Recent inverter designs use pulse width modulation to produce a pulsed waveform that can be filtered easily to achieve a good approximation to a sine wave The advantage of PWM is that the switching techniques result in high efficiency Significant control circuitry and high speed switching are required to make the pulse width vary according to the amplitude of a sine wave This is because the PWM signal has to be filtered out effectively so the frequency of the PWM has to be much higher than the frequency of the sine wave to be synthesized Filtering for the modified sine wave inverter can be further augmented to produce a more approximate sine wave by assimilating another waveform to remove the unwanted harmonics The switching stage could be implemented with a combination of bridge and half bridge components Some DC AC inverters are also designed using the popular 555 Timer IC The 555 inverter in Figure xx connects the IC in mono stable mode and uses it as a low frequency oscillator It has a tunable frequency range of 50 60Hz using the potentiometer It feeds output through two transistors to the transformer The circuit suggests that it produces a virtual sine wave due to the fact that the capacitor and coil filter the input 92 i 3 e2 F R T laa Figure 4 12 Inverter circuit with a
74. as adjustable backlighting which is desired in the system to enhance final user experience Using a voltage divider configuration circuit as a voltage sensor in the design was extremely convenient The resistor values used in the circuit were relatively easy to calculate which makes the overall implementation of the circuit easy to modify and or adjust as required if needed in the future The Allegro ACS712 current sensor from Allegro Microsystems is the final election Current sensor can measure AC or DC current allowing to be moved from one place to another if needed It is fully adaptable to custom PCB design and does not require complicated circuitry to operate On the temperature sensor side the DS1624 Thermometer from Maxim is a digital temperature sensor that fits all of the desire characteristics that are needed DS1624 is well designed to be fully integrated directly with microcontroller without the need of using other external components This sensor has the capacity to be assigned a digital address which allows up to eight temperature sensors to be use in the design and they can all be accessed from the microcontroller through the same 12C bus line Microcontroller will execute specific algorithms which are going to perform IRPS core functions Algorithm order is established based on priority criteria of those components which are more critical if occur a malfunctioning and can propagate a system Below Figure 5 3 pictures the flow dia
75. ave the advantage of having already set if more 12C devices compatible are aimed to be added later As it was argument on DS1624 research chapter and referring to below Table 4 5 DS1624 pins are configured on the best interest of IRPS design Pin 1 and 2 are in charge of the communication so they are connected directly with the microcontroller 72C bus Pin 3 is a pin that is not used therefore is left unconnected Pin 4 and 8 are responsible for powering the chip and grounding the chip respectively The voltage applied at the VDD should be between 2 7 to 5 5 volts Finally pins 5 6 and 7 are used to assign different address to the DS1624 sensors so there will be not identification misdirect between sensor and microcontroller request Pin Symbol Reference 1 SDA Data input output 2 SCL Clock input output 3 NC No connect 4 GND Ground 5 A2 Address input pin 6 Al Address input pin 7 AO Address input pin 8 VDD Supply voltage Table 4 6 Temperature sensor DS1624 pin description 84 4 6 Battery Bank Energy storage must be optimized to ensure the most effective sizing of each of the system components When choosing a battery type for the integrated renewable energy applications there are many factors must be taken into account Those important comparison criteria are possible depth of discharge of the battery cost number of charge or discharge cycles the battery can tolerate efficiency self discharge energy density c
76. average home use 2 2 2 Self Sustained One of the major objectives of the project is that the power system operates independently from other power sources The system will not be connected to the power grid as well 2 2 3 Efficiency The most important purpose of the project is to design a controller that will optimize the performance of the integrated system In other words it is to make the system work more efficiently With the intention of doing that it is essential for the controller to monitor the charging process of the battery and implement a more efficient battery charging algorithm To make the charging process more efficient and easier to implement the case study conducted by Mu Kuen Chen Department of Electrical Engineering at St John s University Taiwan was adopted In his conference paper The Integrated Operation of Renewable Power System he emphasizes the difficulty in integrating wind and solar source with respect to the effect of source impedance He suggests setting different charging modes to optimize the charging operation 1 Therefore the system will be able to charge the battery bank by using both sources sufficiently 2 2 4 Environmentally Friendly The entire system should not produce any undesired consequences to the environment The use of renewable energy sources will reduce greenhouse gas emission 2 2 5 Low Maintenance and User Friendly The system will be portable so that the user will be ab
77. blades can capture wind more efficiently to maximize rotor s output current All this energy produced by the turbines it s free of any type of emissions or other pollutants that may create greenhouse gases Since wind turbines come in a wide range of sizes they can be used by anyone to produce their own additional input power for their household use Usually private companies create wind farms to produce up to 1000MW of electricity However remote areas that are not connected to the electricity power grid can create their own wind farm to supply their own demand of electric power Due that the space required to install a wind turbine is very minimum wind farms can have hundreds of wind turbines Wind farms do not use very much surface space in the case of agriculture this allows to farmers performing ground activities without complications Many land owners benefit from wind turbines when a company plans to create wind farm Companies have to pay for the space that their wind turbines use This is a great complementary source of income that boosts local economies In addition many people view wind farms as an interesting feature that enhance the landscape As there are great benefits from the generation of electric power through wind turbines there are some limitations and disadvantages Wind has an immense power but is not continuous and constant Winds may vary from zero to hurricane force winds This factor unleashes other subseque
78. board is a derivate version of original Arduino board with the main difference that the Netduino is an open source electronics platform using the NET Microsoft Framework Preferred IDE is Visual Studio and language programming is C which is a very sophisticated modern high language Even though IDE is proprietary software from Microsoft and license is far from being accessible from IRPS budget a totally full license is ready to be used from DreamSpark which is an agreement between Microsoft Corporation and University of Central Florida For that reason if AT91SAM7X512 microcontroller is chosen IDE would be available for no cost and could be easily integrated to Netduino development board Some members of IRPS carry a good expertise on the Net framework from Microsoft and having this alternative which could be 53 very suitable was attractive enough to be considered Netduino board is a couple of dollars expensive than its predecessor coming at 34 95 yet is on the budget range 3 10 3 Texas Instruments MSP430 The MSP430 is a well known low cost microcontroller from Texas Instrument this unit has been familiar to every member of this group through academic courses Texas Instrument has exposed several renewable energy harvesting projects based on the technology of this microcontroller based on its characteristics Low operating voltage 16 bit architecture integrated ADC for measurements and low standby current when idle Combining th
79. bserve Method 3 4 3 2 Incremental Conductance Method 3 4 3 3 Constant Voltage Method 3 5 Rectifier 3 6 Voltage Regulator DC DC converter 3 6 1 Buck Converter 3 6 2 Boost Converter 3 6 3 Inverting Buck Boost Converter 3 6 4 Non Inverting Buck Boost Converter 3 6 5 Half Bridge and Full Bridge Drivers 3 6 6 Linear Regulator 3 6 6 1 78XX Three Terminal Linear Regulator 3 6 6 2 Zener Diode Regulator 3 7 Dump and Diversion Loads 3 8 DC AC Inverter 3 8 1 Inverter Efficiency 3 9 Sensors 3 9 1 Voltage Sensor 3 9 2 Current Sensor 3 9 2 1 ACS712 Current Sensor 3 9 2 2 MAX4172 Current Sensor 3 9 2 3 CSLA2CD Current Sensor 3 9 3 Temperature Sensors 3 9 3 1 TMP3e6 Temperature Sensor 3 9 3 2 DS1624 Temperature Sensor 3 10 Microcontrollers Unit 3 10 1 Atmel ATmega328 3 10 2 Atmel AT91SAM7X512 3 10 3 Texas Instruments MSP430 3 10 4 PIC24 from Microchip 3 11 LCD Display 3 12 Analyzing Source Threshold Algorithm 3 13 Batteries 3 13 1 Types of Batteries 3 13 2 Lead Acid Battery 3 13 2 1 Limitations 3 13 2 2 Advantages 3 13 2 3 Types of Lead Acid Batteries 3 13 3 Lithium lon Battery 3 13 3 1 Limitations 27 28 29 30 33 34 35 36 37 39 39 40 41 42 43 44 45 45 46 46 48 49 50 50 51 52 53 53 54 54 55 56 58 59 60 60 60 60 61 61 3 13 3 2 Advantages 61 3 13 4 Battery Charging Algorithm 62 4 0 Project Hardware and Software Design Details 65 4 1 Initial Design Architectures and Related Diagrams 65 4 2 Solar Panel
80. d Energy low wind speed Solar and Wind Energy high wind speed All four of the modes reviewed above will need to be tested to make sure that they are not only working but working efficiently An oscilloscope will be used to measure the charging current and voltage and a current probe will also be used as well The first mode will be tested outside on a sunny day with the wind turbine not connected The oscilloscope will give accurate reading for the charging current and voltages to both Esoiar and Ewing to make sure they are both being charged by the solar panel The second mode will be done at night or the solar panel will be disconnected In Central Florida it is hard sometimes to get a 109 good flow of wind Therefore a shop fan will be used to control the speed of the wind and keep it constant for the duration of tests utilizing the wind turbine Once the wind turbine is the only source running the oscilloscope will record the charging current and voltage The third and fourth modes will tested the same only the wind speed will be increased The most interesting aspect of mode four is to check if Egoia charge current and voltage significantly increase This will indicate that the microcontroller is in fact charging this battery with both the wind turbine and the solar panel Several days of testing under different solar conditions will give all the data needed to determine if the system is integrating both energy sources effect
81. d capacitor A general inverting Buck Boost convertor can be seen below in figure 3 21 Figure 3 21 Inverting Buck Boost Converter with Permission from Creative Commons 36 The Buck Boost converter runs in two distinct stages When the converter is operating in the ON mode the diode will not allow the current to reach the load side of the circuit because it is operating in reverse bias This is also the mode that the inductor will begin to increase the energy stored in it due to the increase of the current from the input source During this stage the capacitor will be used to power the load and the circuit as a whole is behaving like a Boost convertor 26 A diagram illustrating the ON state can be seen below in figure 3 22 On State Figure 3 22 Inverting Buck Boost Converter ON State The second state of the inverting Buck Boost converter is known as the OFF state During this state the inductor s energy is used to supply the load side of the circuit This state is where the inverting Buck Boost convertor received its name The current from the inductor will be the opposite polarity of the input voltage causing the output voltage signal to be inverted The OFF state diagram of the converter can be seen below in figure 3 23 The biggest advantage to this topology is how little components are needed This drastically reduces any losses that might occur throughout the circuit The biggest disadvantage is this circuit can only be used in
82. d here because of the high current that will be produced by the alternators With P I R I being the driving force for the loss in energy by heat it can be easily seen that the loss will rise exponentially The compact size of an IC could be a disadvantage because all the heat would be dissipated in a concentrated area There are also other factors that will disqualify the use of linear regulators for the charging regulating of the batteries There will be a large voltage difference between the alternators and the batteries linear regulator are not usually well suited for this situation and as such they would not be used here Linear regulators will be used for the micro controllers and display segments of the design 3 7 Dump and Diversion Loads The dump and diversion loads are design to deal with the excess power that is generated from the solar panel and the wind turbine The solar panels and wind turbines are designed to be under loads when they are operating The load is usually an electrical load which is drawing electricity that is generated by the solar panel or the wind turbine There are two most common loads for those to generation systems They are battery bank and electrical grid Those electrical loads keep the solar panel and the wind turbine within their designed operation ranges The wind turbine can be self destructed under high wind conditions if it operates without loads For the safety of the operation it is necessary for a wi
83. d you please grant me permission to use your image for my project Below is the link to the article where found the image from HyperPhysics http hyperphysics phy astr gsu edu hbase electronic rectct html c5 Figure 3 26 Permission Granted Description A coloured drawing of the front of a TO 220 transistor package Date 26 March 2007 Source Own drawing done in Inkscape Author nductiveload Permission Reusing this file the copyright holder of this work release this work into the public domain This applies worldwide In some countries this may not be legally possible if so grant anyone the right to use this work for any purpose without any conditions unless such conditions are required by law Other versions ine drawing viii State Energy Conservation Office RE Copyrights Wind turbine mechanism Image Juline Ferris juline ferris cpa state tx us Sent Mon 12 3 2012 5 13 PM To Julio F Lara First Previous You have permission to use the wind turbine picture referenced below Regards Juline Ferris Program Specialist State Energy Conservation Office Texas Comptroller of Public Accounts LBJ State Office Building 111 E 17th Street 1118 Austin TX 78701 512 936 9283 Fax 512 475 2569 http www seco cpa state tx us IMPORTANT NOTICE This communication and any attachments may contain privileged or confidential information under the Texas Public Information Act and or appl
84. dealing with rapidly changing conditions This can sometimes lead to the algorithm to take iterations in the wrong direction 39 Despite all the disadvantages this algorithm is the most commonly used MPPT method because of its simplistic design 3 4 3 2 Incremental Conductance Method Another MPPT algorithm that is a bit more accurate and complex is the Incremental Conductance Method The main idea of this algorithm is to compare the differentiation of the power with respect of voltage to zero and determine if it is greater than or less than zero This algorithm can be seen in Figure 3 11 notice how the differential is less than zero after the maximum power point location and is greater than zero before it 28 Power Voltage Figure 3 11 MPPT Incremental Conductance Method Permission from American Technical Publishers The algorithm will know when the maximum power point location has been found when dP dV 0 39 Unlike the perturb and observe method a discreet value is determined for the maximum power point location in Incremental Conductance method This system will remain at this point until it undergoes a change in the environmental conditions affecting the power 89 The big advantage in this method over the perturb and observe method is that the inequality determine from calculating the derivative gives a direction This will prevent the algorithm from incrementing in the wrong direction 3 4 3 3 Constant Voltage Method C
85. ded to prevent the electronic devices being damaged The system being built for this project was determined 43 by the group to be able to handle 1200W 1500W maximum The invertor that will be purchased must have an output that exceeds the maximum wattage needed Voltage of the invertor Two 12V batteries are being used for this system therefore the DC AC invertor must be rated for 24V This is an extremely important factor because if the inverter does not meet this requirement it might get burned up by the input voltage and possibly destroy whatever electronic device is plugged into it Surge The surge rating is the initial amount of power required by a device when it powers up The initial startup of some equipment can draw much higher energy then when the device is running Every piece of electronics should have this rating in the manufacturer specs The DC AC invertor s wattage threshold needs to be able to handle the surge of whatever type of device that is plugged into the system Wave output When an AC signal comes out of an electrical outlet it will have a perfect sine wave This is not necessarily true when an AC signal outputs the invertor When a DC signal is inputted into the invertor it will boost the voltage up and convert it to an AC signal After this process is done the signal looks more like a Square wave than a sine wave The wave output factor of a commercially purchased DC to AC invertor is the quality of the output sine
86. deep cycle lead acid batteries will be used in the project design Among the deep cycle lead acid batteries flooded gel electrolyte and absorbed glass mat AGM batteries are the most commonly used ones While flooded 85 lead acid batteries are the cheapest type they require maintenance and special shipping methods in transporting due to the risk of acid leakage Gelled electrolyte batteries eliminate the potential of acid leaking but they must be charged at a slower rate C 20 to prevent excess gas from damaging the cells Another disadvantage of this type of batteries is that they must be charged at a lower voltage than the other two types In this IRPS project AGM batteries will be used for energy storage AGM is a newer type of sealed batteries This type of batteries possesses all of the advantages of the gelled electrolyte batteries but they are much durable They cannot spill even if broken As a result they can be transported using normal shipping methods This will lead to a lower shipping cost In addition they can practically resist damage from freezing since there is no liquid to freeze Water loss is also negligible because hydrogen and oxygen are recombined back to water inside the battery while charging at a very efficient rate There is no need to adjust the charging voltage Due to the extremely low internal resistance there will be almost no heating of the battery even under heavy charge and discharge current The on
87. depending on the load connected to it These two reasons make the use of a voltage regulator an essential component to this system For each stage of the battery charge level the voltage will need to be ramped up or down This is known as a switching regulator where a diode Capacitor and inductor are usually used to alter the voltage accordingly Both active and passive switches are used in a switching regulator A passive switch tends to be just a diode and an active switch will usually be a MOSFET transistor The active MOSFET can be an extremely efficient way to switch between the voltage stages because it a digital signal can be used to control the MOSFET This is accomplished through the use pulse width modulation PWM to control the frequency and duty cycle of the MOSFET s on and off switch This will eliminate the need for a digital to analog converter between the microcontroller and the MOSFET The digital signal will also be less susceptible to noise which could cause the switch to have an error Voltage regulators do not produce any power they actually consume a little bit of the input power accordingly to their efficiency rating Since the DC to DC converter consumes some input power this research will be mostly on switched converters instead of linear converters This is because the switched converter tends to be around 80 efficiency which is much higher than linear converters 27 The goal is to keep the power level from moving as m
88. design phase to decide whether it should be included on the integrated control 3 12 Analyzing Source Threshold Algorithm Integrate two different renewable energy sources in one solution would be always challenging at the time of designing the platform due to incomparable sources impedances in this case wind turbine and solar panel In order to implement such feature in this project study has been conducted to not only integrate both sources but also to maximize the charging system Research to be conducted for proper threshold analysis will be enduring and extending article study The Integrated Operation of a Renewable Power System by Mu Kuen Chen presented to IEEE Canada Electrical Power Conference in 2007 Chen s work demonstrated through theoretical analysis and field experiment that traditional method couldn t be used to charge batteries from wind power and solar energy if used at the same time 1 The truthful study by Chen was conducted almost five years ago giving time to this implementation being settled then current research will pick from there and look towards an enhanced microcontroller based solution Due to large output fluctuation on both sources based on weather condition and itself efficiency it is debatable whether the best solution would be to combine both existent sources alternating charging cycles or to create two separate bank of batteries one dedicate to solar collection and the second one to wind energy
89. dex com Hello Cadex Electronics am in an electrical engineering senior design class at the University of Central Florida in Orlando FL am currently working on creating an integrated renewable power system controller for my senior design project and I would like to request permission to use one of your graphs in our documentation would like to request permission to use the Charge stages of a lead acid battery from the following page http batteryuniversity com img content clead1 j Please let me know if we would have permission to use these figures for a strictly academic and informational purpose in our project research documentation Thank you Sincerely Jing Zou Undergraduate Student Electrical Engineering Department University Of Central Florida xiv http upgi com Copyright Permission Request jingzou Sent Sun 11 25 2012 12 05 AM To sales upgi com Hello UPG am in an electrical engineering senior design class at the University of Central Florida in Orlando FL am currently working on creating an integrated renewable power system controller for my senior design project and I would like to request permission to use one of your picture in our documentation would like to request permission to use the UB12180 from the following pages http upgi com Themes leanandgreen images UPG ProductImages D5745 jpg Please let me know if we would have permission to use this figure for a strictly acad
90. dgeable about system status The sensors duty is being on top of system measurements at every moment and be able to feed microcontroller inputs to allow data to be analyzed Having the microcontroller aware about what is happening in the system will create whole system reliability since critical decision can be taken dodging painful situations where some components can be seriously damaged and further causing system malfunctioning The control box is the brain with the responsibility of accomplishing this project s main purpose of maximizing energy harvested and making the system work under optimal conditions 2 2 9 Energy Storage The performance of the batteries in a renewable energy system is the key to its success The main objective of the batteries is to maintain the consistency and balance of energy within the renewable energy system There will be two batteries used in our Integrated Renewable Power IRP System to store the energy that is collected by both the solar panel and the wind turbine when there is an excess of supply Both of the batteries will be used when the power collect by solar panel and wind turbine is not sufficient enough to supply the loads as well Therefore the battery is required to have a large capacity so that users can run the loads at any time as they desire The battery bank helps stabilize the system by ensuring that there will be sufficient power supply to the load The batteries should be low cost technological
91. dget and Finance Discussion 8 2 1 Budget The concepts of IRPS controller design will be verified by establishing a fully functional sustainable system The budget is presented in table 8 6 below All of the required parts for creating the IRPS controller are included This project is sponsored by Progress Energy through University of Central Florida Foundation The cost of miscellaneous has not included in the table Cost per Number Total Parts hist Part of Parts Cost Solar Panels SW S85P Solar Panels 249 85 1 249 85 Mounting Braket 50 00 1 50 00 Wind Turbine Apollo 550Watt 12V DC 435 1 435 Charge Controller SM72442 Prog MPPT Free 2 Free Printed Circuit Board Student Special 33 00 4 132 00 DS1624 Temperature Sensor 9 00 1 9 00 ACS712 Current Sensor 9 95 1 9 95 Voltage Sensor 5 00 4 20 00 LCD Screens 29 95 2 59 90 Battery UPG UB12180 AGM type Battery 49 98 2 99 96 Dump Load Resistors 300 Watt Dump Load for 12 Volt Systems 21 98 3 65 94 Converter Outputs DC AC 50 00 1 50 00 LT1160 Half Bridge Drive 3 00 2 6 00 Microcontroller Development Board Atmel AT91SAM7X512 21 51 2 43 02 Netduino 34 95 1 34 95 Total 1265 67 Table 8 6 Anticipated Budgets 118 8 2 2 Finance Discussion The main objective of IRPS project is to design a top efficient integrated power system as a proof of standalone system usin
92. e various forms and types of cell batteries Based on the material cell batteries categorized to the following Lead Acid Batteries They are the cheapest and most popular The tolerance of depth of discharge is 75 and the life span on this depth of charge is 1000 to 2000 cycles Lithium lon Li lon Batteries They have a very high efficiency of 100 more cycles of life span 3000 cycles and greater depth of discharge 80 They have negligible self discharge However they are very expansive Sodium Sulphur NaS Batteries They are very efficient in the use of daily charge and discharge They also have negligible self discharge However they must be kept at 300 C This increases the difficulty of maintaining the system Nickel Cadmium NiCd They have a very large capacity which can be up to 27 MW of power In addition they have more life span cycles and greater depth of discharge then the Lead Acid Batteries Nevertheless they are expansive and toxic and their self discharge is high Zinc Bromine ZnBr Batteries They have high power and energy density but the technology is less matures then the others They are also toxic Therefore in the IRPS the best option will be Lead Acid Batteries comparing with other battery types considering the combination of performance and cost A summarized battery characteristics table is shown below 48 Attributes Lead Acid Li lon NaS Ni Cd Zn Br Depth of 75 80 100 100
93. e and amp vs RPM graph for the research part of our project Would you please grant me permission to use your image for my project We will answer as soon as possible GreenergyStar Grid Tie Inverter Grid Power III 600W For Solar amp Wind Hybrid Systems powered with PrestaShop https www sparkfun com SparkFun product photo permission castex Sunday December 02 2012 11 40 AM To marketing sparkfun com Good morning SparkFun staff my name is Karel Castex and I m a Computer Engineer student at Universal of Central Florida At the moment I m doing my senior design project or my graduation thesis and I would like to as for permission of using the ACS712 breakout board picture located at https www sparkfun com products 8882 The sensor is aimed to be the current sensor to be used in our project Thanks in advance Karel Castex xii http scienceshareware com CLSA2CD Sensor picture permission castex Sunday December 02 2012 11 45 AM To bdwhaley scienceshareware com Good morning my name is Karel Castex and I m a Computer Engineer student at Universal of Central Florida At the moment I m doing my senior design project or my graduation thesis and I would like to ask for permission of using the CLSA2CD Sensor picture located at http scienceshareware com how to measure AC DC current with a hall effect clamp htm The picture is the first from top to bottom and it is aimed to be an alternative o
94. e discharging time of the battery the following steps should be taken 1 A predetermined load is needed The battery should be connected to the inverter with the predetermined load For the expected result the battery should start to slowly discharge 2 Connecting a multi meter to check the voltage of the battery during the discharging process The voltage reading on the multi meter should decrease gradually from fully charge 110 3 The current going through the battery should also be checked by using a multi meter The current that is drawn from the battery should show on the multi meter reading The time taken for the battery to reach its final discharge stage should be monitored closely as well According to the battery and load ratings the time it takes for the battery to discharge to its final discharging current at 3 0 CA is eight hours The monitor the time should match the expected time 7 7 Wind Generator Rectifier Testing In order to ensure the quality and effectiveness of the rectified ac signal several steps will be taken to analyze the bridge rectifier First the wind generator rotor needs to be stopped and be maintained off of operation This ensures the bridge rectifier is without power Check the rectifier to confirm that it is set up correctly Diodes should be placed in the circuit with the silver band end in the negative direction The circuit will not operate properly if the diodes in the rectifier are not
95. e lead acid battery will allow batteries to be periodically charge and discharge They are normally used for photovoltaic systems and electrical vehicles They are also widely used as continuous power supplies This type of batteries is designed to have large capacity and high cycle count but the batteries have a relative low current output 49 Therefore deep cycle battery is preferred for this project Thus even though there are many rechargeable batteries can be found in the market deep cycle lead acid battery will be used in this project because of the combination of cost and performance 3 13 3 Lithium lon Battery Lithium ion batteries are one of the commonly used batteries in consumer electronics They are also one of the most popular among the rechargeable batteries especially for portable electrical equipment Moreover the Li ion batteries are used in military electric vehicles and aerospace applications This type of batteries has advantages over other batteries as well as some disadvantages 3 13 3 1 Limitation The limitations are the following e Li ion batteries are much more expensive than the lead acid batteries They tend to have one of the highest cost per watt hour ratios e There are also more safety requirements need to be concerned for li ion batteries They are quite sensitive to the temperature Overheating or overcharging may cause the battery to suffer thermal runaway and cell rupture 47 What is worse comb
96. e mounted on standard free printed circuit board its breakout is pictured in below Figure 3 29 46 Figure 3 29 ACS712 breakout board Reproduced permission pending Previous configuration of ACS712 sensor contains a thick copper conductor and signal traces allowing the sensor handle up to 5 times the overcurrent without tampering against proper functionality ACS712 is flexible to configure its bandwidth and this is done set via FILTER pin clearly described in above Figure 3 29 Also this sensor depend upon on a DC 5V in the Vcc in order to function and it should feature some filter capacitors to avoid any noise signals coming from supplied voltage 37 The sensor compose a precise low offset circuit where an applied current flowing through copper conduction path develop a magnetic field which is sensed by the integrated Hall IC and converted into a proportional voltage which would be provided to ADC placed before microcontroller 36 ACS712 features a package of 5 Amp 20 Amp and 30 Amp version which guarantee a good variety from where to be chosen based on our project design Additionally Allegro specifies that one should expect only having a 1 5 output error at 25 degree C when sensors can fully operates from 40 to 85 degree C and that device is Pb free being exempt from RoHS Combining the fact of sensor having an internal resistance of 1 2 mQ which ensure low power loss with previously explained sensor s versatile design integrat
97. ed by IRPS in coordination with UCF graduate student cursing a master program with focus area in Project Management Implemented economic analysis will refer to how feasible is to create the mentioned integrated renewable energy system for residential and small businesses Taken into account average energy consuming in households and small business it was decided to run a complete analysis with an integrated system capable of delivering 1 5 kW which represent a larger model than IRPS prototype capacity To develop this analysis study accounted for the system final price as well as the determination of how feasible is for the final client to make an investment of this nature Also study covers on how advantageous would be the large scale production for this type of system To reach final conclusion of these studies Net Present Values NPV were estimated considering today and forecast s market situation Study relies on computer simulations to calculate the power output of the whole system These simulations were modeled using Homer software which is a tool for designing and analyzing hybrid power systems Homer contain predetermined conventional generators wind turbines solar photovoltaic batteries and other inputs system was modeled with customized elements taking into account the characteristics of the equipment and components to be utilized on the construction of this hybrid system Below it can be found some of the relevant information used f
98. ed in a charge controller for getting the maximum voltage possible out of the solar array Solar cells have a non linear output voltage which is known as the I V curve This is due the complex relationship between the solar cell solar irradiation temperature and total resistance It is the purpose of the MPPT system to sample the output of the cells and apply the proper resistance load to obtain maximum power for any given environmental conditions 37 The fill factor is a parameter that deals with this non linear electrical behavior The fill factor FF is defined as the ratio between maximum power of the solar cell to the product of the open circuit voltage V and the short circuit current lsc Therefore the maximum power can be calculated with this equation 3 2 shown below 37 P FF Ve Isc Equation 3 2 Formula for Maximum Power Now that the maximum power has been explained it is easier to understand where the maximum power point is located Since P V I the maximum power point location can be determined through simple calculus Therefore the maximum power point location can be defined as dP dV 0 37 This means that the maximum power point location is at the knee of the I V curve The purpose of the MPPT system is to track this location for the maximum power The MPPT can be seen below in Figure 3 9 intersecting all the I V curves at the maximum power location during varying sunlight 26 Fig
99. ed in below Figure 4 10 Figure 4 10 Rectified Output to 3 3 V scaling and rectification application Derived from ACS712 datasheet The important features that ACS712 is bringing to IRPS are e 5 us output rise time in response to step input current e 80 kHz bandwidth e Total output error of 1 5 at Temperature ambient of 25 C e 1 2 mQ internal conductor resistance e 5 0 V single supply operation e 66 to 185 mV A output sensitivity 83 e Extremely stable output offset voltage 45 43 Temperature Sensor The DS1624 Thermometer from Maxim is a digital temperature sensor that fits all of the desire characteristics that are needed in IRPS DS1624 is well designed to be fully integrated directly with microcontroller without the need of using other external components At the moment it is devised that one DS1624 would be used to measure environmental temperature such information will allow to microcontroller to decide limits on battery thresholds since they vary by weather season The main features important for IRPS design are Communication type 12C Bus VDD of 2 7 to 5 5 V input power Range of temperature is of 55 C to 125 C The temperature is read as 13 bit value 8 pin DIP The ample temperature range where sensor operates brings the advantage to be exposed to high temperatures and still providing accurate readings Since sensor use 1 C bus for communications will enable the possibility to implement this channel and h
100. ed to the amperage input Turn the panel in a northern direction and attach the probes to the output of the solar panel While the probes are attached slowly turn the solar panel to the south and tilt it to the optimal angle with the sun The multi meter should show the amperage increasing until it reaches the value from the spec sheets 52 According to the manufacturer this value should be near 5 4A for the SunWize SW S85P These steps should properly ensure that the solar panel was not damaged in the delivery This will also give the group a good idea of the average open circuit voltage and short circuit current of the SunWize SW S85P With these figures known the circuits used on the solar side of the system can be more accurately simulated inside the lab 103 7 2 Wind Testing The wind generator is going to be tested so it can be measured the power curves advertised by the vendors This power curves can be found in the manufacture s website magazines where the manufacture publish their product or in the manuals that come with the hardware Power curve is a graph indicating how much power in watts or kilowatts a wind generator will produce at any given wind speed Power is presented on the vertical axis wind speed on the horizontal axis Wind generators reach their rated or nominal power at their rated wind speed in mph or meters per second m s Rated power is not synonymous with peak power though they are occasionally the same Rated
101. egulator can be made to regulate much better by adding an emitter follower stage which forms a simple series voltage regulator In this circuit the load current is now connected to a transistor whose base is connected to the zener diode The transistor base current lg now forms the load current for the zener diode and is much smaller than the load current This forms a very light load on the zener minimizing the effects of variation in the load it is still however sensitive to load and supply variation It is also important to note that the output voltage will always be about 0 6V to 0 7V less than the zener because of the transmitter Vee drop The circuit is referred to as series because the regulating elements transistor and diode are in series with the load R still determines the zener current and can be calculated by the following formula where hfemin is the minimum acceptable DC current gain for the transistor and K is equal to 1 2 to 2 which ensures R is low enough for an adequate Ip Ri V V lz K Ig Ig l hpeg min 41 RL 50 Figure 3 28 Zener Diode Regulator with Emitter Follower Linear regulators whether in the integrated circuit or diode form are cheap readily available and reliable They are also simple to design and implement There are drawbacks to linear regulators however they are not very efficient as they waste a lot of energy by heat dissipation This loss of energy by heat will be very pronounce
102. emic and informational purpose in our project research documentation Thank you Sincerely Jing Zou Undergraduate Student Electrical Engineering Department University Of Central Florida XV Appendix C Figures Figure 2 1 Monthly Consumption of renewable energy by fuel type Jan 2000 Apr 2011 Figure 3 1 Best Cell Efficiencies created by L L Kazmerski Figure 3 2 Temperature effect on PV panel performance Figure 3 3 Annual Solar Radiation of the United States Figure 3 4 Wind Generator Mechanism Figure 3 5 AWEA Infographic Figure 3 6 The Daily Charge Profile of a Shunt Interrupting Controller Figure 3 7 The Daily Charge Profile of a Series Interrupting Controller Figure 3 8 The Daily Charge Profile of a Series Linear Controller Figure 3 9 Solar Cell l V Curve in Varying Sunlight Figure 3 10 MPPT Perturb and Observe Method Figure 3 11 MPPT Incremental Conductance Method Figure 3 12 MPPT Constant Voltage Method Figure 3 13 Rectified Sine Wave Figure 3 14 Full wave rectifier Figure 3 15 Full Bridge Controller Figure 3 16 RMS Ripple Voltage Figure 3 17 On State of a Buck Converter Figure 3 18 Off State of a Buck Converter Figure 3 19 3 State of a Buck Converter Figure 3 20 Schematic of a General Boost Converter Figure 3 21 Inverting Buck Boost Converter Figure 3 22 Inverting Buck Boost Converter ON State Figure 3 23 Inverting Buck Boost Converter OFF State Figure 3 24
103. en to the RC network on the output The current will become zero and tends to reverse however the diode will prevent conduction in the opposite direction 29 The inductor will also discharge in this state a figure of the second state and the equations that govern it can be seen below OffState a tee Vo dt C gp a di Vo dt L Figure 3 18 Off State of a Buck Converter with permission from Creative Commons The third stage of the Buck converter the switch and the diode are both off The capacitor is discharging and the inductor is at rest with no energy in it The 34 inductor will not acquire or discharge any energy during this stage 29 A diagram of this stage and the equation of the voltage behavior can be seen below L V Vo i d C Figure 3 19 3 State of a Buck Converter with permission from Creative Commons There are five basic components to the switched Buck converter Inductor capacitor diode PWM controller and a transistor switch 29 The inductor is placed in series with the load resistor to reduce ripple in the output current This reduction occurs because the current in the inductor cannot change suddenly An inductor tends to act like a source when the current level drops The inductors used in most Buck converters tend to be wound on toroidal cores and made of ferrite or powdered iron core with distributed air gap to minimize core losses at high frequencies 29 The capacitor is ins
104. ent price we used the cost plus pricing strategy which according to Godfrey it determines the expense associated with producing a product and add an additional amount to that number to generate profit and is relatively simple as it only requires the unit cost and desired profit margin for calculation Unit cost consists of all fixed and variable costs associated with making a product and bringing it to market including raw materials labor utilities packaging transportation marketing and overhead Profit margin is the markup on each unit sold which can vary for retail and wholesale sales 57 Given the above concept for this pricing strategy it was calculated the system cost based on the list of elements required to build the system The system cost was estimated at 3 810 8 thus we set the margin profit to a 20 of this cost and a 10 for installation costs leading us to an approximated price before sale taxes for the final client Final price System costs margin profit installation costs Final price 3810 8 0 2 3810 8 0 1 3810 8 Final price 4954 04 Holding up to calculated final price for client and consider that an investment is measured by its impact over time positive or negative on the organization s cash position 58 this analysis would be based on the Net Present Value NPV Two main distinct states would be considered based on that positive cash flow indicates an inflow of ca
105. entation of the design will be constructed on a custom ordered printed circuit board PCB Table 2 2 shows the specifications of the microcontroller and the LED in the control box Microcontroller Clock Frequency Low Serial Ports Yes Programming Language High level similar to C Programming Memory 216K Analog Pins Yes Digital input output Pins Yes PWM Output Pins Yes Programming Debugging Yes Power consumption Low good sleep mode LCD Current Draw Low Voltage Low Lines Needed 1to3 Table 2 2 Control Box Specifications In order to charge the battery the power produced by both sources has to meet the input requirement of the battery bank Therefore a DC DC inverter will be inserted at the input of the batteries While with the purpose of powering electronic devices with AC power a DC AC inverter needs to be inserted at the out of the batteries Battery Bank Voltage 12V Depth of Discharge 75 Lifespan Cycles 1000 2000 Efficiency 72 78 Cost Low DC DC Inverter Voltage Regulator Maximum Voltage gt 15V Output Voltage gt 12V DC AC Inverter Continuous Max Power 1200 1500W Input Voltage 12V Output Voltage 110 120VAC Table 2 3 Power Charge Storage and Delivery Specifications Chapter 3 Research 3 1 Related Projects As the fast increasing demand of renewable energy there are numerous researches on making a more stable consis
106. er the inverter will be drawing 40 watts from the batteries and the efficiency will only be 50 A small 200W inverter may on the other hand only draw 25 watts from the battery to give an AC output of 20 watts resulting in 44 an efficiency of 80 Larger inverters will generally have a facility that could be named a Sleep Mode to increase overall efficiency This involves a sensor within the inverter sensing if AC power is required If not it will effectively switch the inverter off continuing to sense if power is required This can usually be adjusted to ensure that simply switching a small light on is sufficient to turn the inverter on This does of course mean that appliances cannot be left in stand by mode and it may be found that some appliances with timers eg washing machine reach a point in their cycle where they do not draw enough power to keep the inverter switched on unless something else i e a light is on at the same time Another important factor involves the wave form and inductive loads i e an appliance where an electrical coil is involved which will include anything with a motor Any waveform that is not a true sine wave i e is a square or modified square wave will be less efficient when powering inductive loads the appliance may use 20 more power than it would if using a pure sine wave Together with reducing efficiency this extra power usage may damage or shorten the life of the appliance due to overheating
107. er words the air is lighter and is thus less effective location for wind turbine to operate In lower altitudes such as near the sea level the air is dense and heavy making it much more effective to turn the wind turbine The radius of the blades determines the amount of wind that can be harvested A large blade will be able to yield much more wind and thus the diameter of the blade can as substantially establish power levels 20 18 Rotor blade Rotor hub with blade pitch mechanism Yaw System Tower Grid Foundations Connection Figure 3 4 Wind Generator Mechanisms 3 3 3 Wind power Performance Ideally our project would work for a combined system of wind power and solar energy that both combine will deliver up 1 5 kW for a typical household To satisfy this demand a wind turbine capable to deliver up 1KW at 24 V will be needed There are many products in the market that with such specification that would fit for our project However the prices of an standard wind turbine that delivers up to 1KW range from 800 to 1000 Our budget is very limited and acquiring such turbine will leave us in negative Since our main goal for this project is to build an integrated circuit box that controls input power from solar and wind energy stores the energy manage the excess of energy and delivers energy efficiently the wind turbine will be scaled down For testing and illustration purposes a wind turbine that delivers fro
108. ercentage of the overall layout of the main control unit printed circuit board design All of the PCB hardware will be purchased from 4PCB com 4PBC com offers reasonable prices for the needs of this project Among their good offers two offers match the requirements for this design The first one is the 2 Layer Printed Circuit Board Designs for 33 each The specifications are shown in table 6 1 The maximum size is 60 square inches and the minimum line space and size of the hole are 0 006 inch and 0 015 inch respectively There are maximum 35 drilled holes on a square inch Min qty 4 Boards White Legend 1 or 2 sides Lead Time 5 Days 1 Part Number Per Order extra 50 charge for multiple parts or step amp repeat 2 Layersm FR 4 0 062 1 oz cu Max size 60 sq inches Plate Lead FREE Solder Finish No slots or overlapping drill hits Min 0 006 line space No Internal routing cutouts Min 0 015 hole size No scoring tab rout or drilled hole board separation All Holes Plated Routed to Overall Dimensions Green LPI Mask Max 35 drilled holes per sq inch Credit Card Order Only Table 6 1 2 Layer Printed Circuit Board Specification The second type is the 4 Layer Designs which is 66 each The specifications are shown in Table 6 2 below Comparing to the 2 layer PCB the 4 layer one has a maximum size of 30 square inches The minimum line space size of the hole and maximum drilled holes pe
109. es as quickly as possible the group decided the solar tracking system would use too much of the power being produced Every month the solar panel s angle will have to be set manually The mounting bracket will not only increase the amount of sunlight reaching the solar panel but it will also protect the panel from high winds Since Florida is an area of the country that tends to have hurricanes this will be necessary to protect the panel There are many different universal solar panel ground mounts and after some research it was determined that one can be acquired for around 50 00 67 4 3 Wind Power Generation So far there are two main options that fit our specifications 1 option THE WORKHORSE 250 watt 129 The first option is a low budget wind generator that delivers 250 Watts It is sold widely on eBay by various vendors The price for this unit is 129 it includes rotor blades tail protective diode generator and screws This unit will be purchased in case our budget gets reduced This unit is designed to charge a 12 volt dc auto or marine style battery in low wind areas with very little installation time or experience A 15 mph wind will give 15 volts which is enough to begin charging your batteries The higher the wind the faster your batteries will charge The unit has a tail section which simply screws together with the body and then the blades bolt onto the hub A 10 amp diode is included with the unit which keeps the motor
110. existing fossil fuel based generating system 3 This project is designed for a larger scale Moreover by integrating with the fossil fuel based generation there will be more emission produced by the system 3 2 Solar Power 3 2 1 Advantages and Limitations Solar power is an alternative power source that is both abundant and clean However solar power has a limitation which is the main reason it only accounts for about 4 of the world s electricity 1 The biggest advantage to solar power is that it emits no greenhouse gases which makes it an incredibly attractive energy source to help curb climate change effects on our planet A good example of this feat is Italy s Montalto di Castro solar park which avoids 20000 tons of carbon emissions a year 2 Another enormous advantage for solar power is infinite free energy Solar does not require any raw materials such as coal or oil to be continuously transported to the power plant adding more cost to the product The labor cost is also significantly lower at a solar power plant than a fossil fuel one because the sun and the solar semi conductors do most of the work Solar power is largely unaffected by the politics that endlessly drive the price of fossil fuels up The US gets a large amount of its oil from regions of the world that are extremely volatile or unfriendly to US interests Prices of fossil fuels have more than doubled in the past decade due to price manipulation through wars and poli
111. f charge Unfortunately the performance of battery charging wind generator is partly a function of battery voltage Scoraig Electric s Hugh Piggott notes that a wind generator s low wind performance improves as voltage decreases He says that permanent magnet alternators need to reach a certain speed to produce the necessary voltage to begin charging the batteries When battery voltage is low the alternator speed at which charging begins is accordingly lower and the wind generator s cut in wind speed is lower In high winds Piggott says losses depend on current and you can get more power out of a given current when voltage is high because power is the product of voltage and current 53 In addition on the battery charge controller side the losses are proportional to the type of material copper has less resistance than aluminum diameter thick cable has less resistance than thin cable and distance to the batteries short cables have less resistance than long cables These resistive losses are reflected in the voltage drop between the wind generator and the batteries The length diameter and material used in the cables connecting the wind generator to the batteries determine the resistive losses between the wind generator and the batteries Manufacturers specify the cable size and material for a range of 105 distances between the wind generator and the batteries that will allow their wind generator to perform as designed 7 3 Microcont
112. f current sensor to be used in our project Thanks in advance Karel Castex Adafruit Industries Adafruit Industries 150 VARICK ST NEW YORK NY 10013 Fax 917 210 3397 Tel 646 248 7822 no phone orders Please note Adafruit does not have a retail store orders cannot be picked up Our factory is not accessible for visitors at this time If you need technical support for your purchase please visit the Adafruit customer support forums We have a dedicated staff of engineers in our customer support forums who can assist you immediately Our engineers can answer your questions and assist you 24 7 in the Adafruit customer support forums Contact Us Required information Full Name Email Address castex knights ucf edu Confirm E Mail castex knights ucf edu Category Press media inquires iv Good morning adafruit staff my name is Karel Castex and I m a Computer Engineer student at Universal of Central Florida At the moment I m doing my senior design project or my graduation thesis and I would like to as for permission of using the TMP36 picture located at http learn adafruit com tmp36 temperature sensor The picture is the second from top to bottom and it is aimed to be the temperature sensor to be used in our project Thanks in advance Karel Castex xiii http batteryuniversity com Copyright permission request jingzou Sent Mon 12 3 2012 3 10 PM To isidor buchmann ca
113. from the batteries and the efficiency will only be 50 A small 200W inverter may on the other hand only draw 25 watts from the battery to give an AC output of 20 watts resulting in an efficiency of 80 Larger inverters will generally have a facility that could be named a Sleep Mode to increase overall efficiency This involves a sensor within the inverter sensing if AC power is required If not it will effectively switch the inverter off continuing to sense if power is required This can usually be adjusted to ensure that simply switching a small light on is sufficient to turn the 112 inverter on This means that appliances cannot be left in stand by mode and it may be found that some appliances with timers eg washing machine reach a point in their cycle where they do not draw enough power to keep the inverter switched on unless something else eg a light is on at the same time Another important factor involves the wave form and inductive loads ie an appliance where an electrical coil is involved which will include anything with a motor Any waveform that is not a true sine wave ie is a Square or modified square wave will be less efficient when powering inductive loads the appliance may use 20 more power than it would if using a pure sine wave Together with reducing efficiency this extra power usage may damage or shorten the life of the appliance due to overheating The following steps will help us determine whether the
114. g In total there will be the following parameters Solar Power voltage current Wind turbine Power voltage current Battery 1 Status level of charge voltage Battery 2 Status level of charge voltage Any custom message displaying system status e Alerts In addition it is highly desired that chosen LCD will be compatible with microcontroller unit to make process smoothly integrated and at the same time to have its own light to make it visible even at dark places Backlight feature seems to be necessary based on the projection that our controller box should be under roof to avoid get the components wet or damage by inclemency of weather then a little enhancement to make the LCD readable at any time is deemed to be necessary even at the cost or increase LCD power consumption Two types of LCD being considered are the alphanumeric and Dot matrix Alphanumeric type is very simple to interact with as well as it comes with many symbols to be used Downside part of this version is the limitation of information to be displayed since any data not complying with existing symbols cannot be interpreted then the flexibility at the time of representing the output is not the strong argument on alphanumeric LCD On the other hand dot matrix LCD possess the capability of receiving a wider range of characters and to choose where to positioning them in the matrix coordinate row column Dot matrix version increase the degree of freedom whe
115. g the benefits of solar and wind energy The following budget presented in Table 8 6 above includes the required parts that were obtained to create an off the grid integrated energy system The project can be divided into fourth major sections First section embraces a 550 W 12V DC wind turbine and SW S85P 100 W 12 V solar panel Second partition includes the PCB board with converters inverters charge controllers and other electronics Third section is dedicated to controller box with all components Fourth partition is mainly composed by wind and solar banks using AGM batteries Project has performed a period of designing and documenting as part of the first cycle It is deemed that second phase will count with a period of testing and building the circuit on a solder less plug in breadboard The funding for this project is provided through a grant from Progress Energy The grant is based on renewable energy programs and was intended to support senior design projects working on projects in these industries Groups were required to provide a proposal and an initial budget for their project in order to apply for the funding The group was funded based on the proposed budget provided to Progress Energy Since IRPS carries good characteristics of being a finalized product to be launched into the market it was conducted an exhaustive study about energy savings for clients and long term profitability for large scale production Economic analysis was manag
116. ge Esolar bank and wind turbine output charge Eying and also Esolar bank energy sources are maximized and fluctuations in the wind power generating are decreased 1 Second alternative is sketched in below Figure 3 35 where it can be observed how the microcontroller will be in the middle of the charge decision making In addition there is a completed and resumed scenario situations depicted in below Table 3 4 N Vo_solar Vo wind A _ a ae Control gt P li Box ower Splitter E solar E wind bank bank Figure 3 35 Microcontroller Alternative to Maximize Efficiency Energy Source Solar Energy Ewind E solar Win Energy 2 fF Solar and Wind Energy low wind lt gt speed p Solar and Wind Energy high wind lt gt 3K speed Table 3 4 Microcontroller Alternative Charging Modes 3 13 Batteries Battery is the most popular and technologically matured energy storage option It is very important to adapt batteries within the stand alone IRP system especially hybrid solar and wind power generation system The battery bank balances the energy within the IRP system It also improves the overall efficiency and consistency of the system by ensuring that there is sufficient supply for the load 58 3 13 1 Types of Battery Cell batteries are the most commonly used form of energy storage There ar
117. gram of main methods to be executed 99 Check Storage Check Temperature Check PV Check Wind Threshold Analysis Charging Procedure Display Status HH Figure 5 3 Algorithm Implementation Flow Diagram Microcontroller will continuously execute the sequence above and loop over it at same cycle time which is defined by the best execution model Above Figure 5 3 enumerate the main logical methods describing consequent steps to be implement however those main methods will use others sub methods serving as helpers Necessary sub methods are not present in flow diagram because some changes are expected when IRPS platform start to be developed 100 Chapter 6 Project Prototype Construction Plan All of the components will be placed on printed circuit boards and since the price of the printed circuit boards is dependent on the size the design will be as space efficient as possible In order to keep the PCB as small as possible the smallest part available that meets our criteria will be chosen The plan is to surface mounting as many of the components as possible so when there are options the product that is made to be surface mounted will be selected It has been decided that this design should go with as many surface mount products as possible This is because they are generally smaller than their through hole counterparts and more cost effective The main microcontroller will be small and only account for a small p
118. h the following formula O amp M PIC 1 OMIR PIC present value of operation and maintenance costs percent of installed costs OMIR Operation and maintenance inflation rate y number of years that project has been implemented Finally in the case of net energy savings was used an energy inflation rate of 2 based on historical data from US Energy Information Administration Formula used to compute this value was NES SPO ER 1 EIR SPO Year based system power output KWH ER Energy rate cents per KWH EIR Energy inflation rate Using excel spread sheet was developed a complete set of tables with numerical result whose numbers represent each state in the residential and small business field Figure 8 2 allows to quick observing the compiled outcome for NPV calculations stating at what state it is profitable for clients to invest on large scale version of IRPS 122 souti emoj sewey N a N aSSHAL 2 yowa UISUOD SIA eweqejy Jopnwey iddisas opesoy ewojyeg see uo uYseN L hA a 2 a spa nipe sey anysiwey may ejueaj suua d eguno yo puy euyoseg yy euu yos New England Residential M East North Central Residential E South Atlantic Residential WestSouthCentra Residential lll Pacific Contiguous Residential I New England Commercial Bi East North Central Commercial Bi South Atlantic Commercial Hi West South Central Commercial J Pacific Contiguous Commercial 5
119. her to make one silicon panel Polycrystalline or multiple crystal panels are popular for residential use because of their low cost and average efficiency 9 As stated above the efficiency is not as high as mono crystalline so it has always been assumed that the mono crystalline are superior but this is not necessarily true After much time spent looking at different companies specs on their products it is clear that polycrystalline panels vary quite a bit from each other and should be considered on a case by case basis Some of the examples that have been found include Conergy s Powerplus P series modules have a maximum efficiency of14 18 and Suntech s polycrystalline Pluto technology has been able to achieve a 20 3 10 These numbers were of course reached in laboratory conditions however they are still impressive The prices for this type of solar panels are perfect for our budget and will most likely be the panel type used for this project 3 2 2 3 Thin Film and Amorphous Silicon Thin film and amorphous silicon panels are the newest generation of solar technology Thin film panels can be produced out of many different compounds that were mentioned earlier in this chapter Once the thin film is manufactured it is usually placed between two glass panels to protect it this will make the thin film panel quite a bit heavy then its silicon counterparts The semiconductor is place between the glass plates A flexible laminate can also be used
120. icable state and federal laws If you have received this message in error please notify the sender immediately Dear Juline Ferris I m working on my senior design project and part of the project is the research and documentation of the project found a very good image from www energyeducation tx gov that would like to add to my research paper Would you please grant me permission to use your image for my project Below is the link to the article where I found the image from www energyeducation tx gov http www energyeducation tx gov renewables section 4 topics windmills or turbines e html Best Regards Salis ot Lara AWEA Copyrights Infographic Julio F Lara Sent Mon 12 3 2012 12 44 AM To websupport awea org Ce Julio F Lara Hi I m working on my senior design project and part of the project is the research and documentation of the project found a very good image from the AWEA that I would like to add to my research paper Would you please grant me permission to use your image for my project Below is the link to the article where found the image form the AWEA cleantechnica com 2012 08 10 us reaches 50 http www powerofwind com uploads files INFOGRAPHIC_AWEA jpg Best regards Salis of Lara Workhorse Dear bufalo_jl yes billydan2011 From bufalo_jl To billydan2011 Subject Other bufalo_jl sent a message about WIND GENERATOR TURBINE WINDMILL NEW ITEM
121. ice and lack of availability SunWize is the company that builds a solar panel that best suites the needs of this project Table 4 1 below shows the specs of SunWize s SW polycrystalline silicon panels The SW S85P model is the model that has been selected for this system This model is within our budget and it has close to the 100W output that was originally desired The best price that has been found online is at solarhome org at 249 85 which is much cheaper than the 375 00 price at the manufacturer s website Model Rated Rated Rated Open Short Weight Power Voltage Current Circuit Circuit Ibs W Vmp Imp Voltage Current Voc Isc SW 55 17 4V 3 15A 22 0V 3 3A 14 0 S55P SW 65 17 4V 3 7A 22 0V 4 1A 14 1 S65P SW 85 17 4V 4 9A 22 0V 5 4A 18 0 S85P SW 110 17 4V 6 3A 22 0 V 6 6A 21 4 110P SW 130 17 4V 7 4A 22 0V 8 1A 25 4 130P Table 4 1 SunWize SW Series Polycrystalline Silicon Panels 47 As discussed in chapter 3 3 4 temperature can be a large negative factor in the solar panel as far as voltage loss is concerned The electrical and thermal parameters for the SW S85P solar panel must be kept in mind if the system starts to show signs of voltage loss due to the Florida temperatures The SunWize panel was chosen because it was believed to be a good model for dealing with the climate here in Florida The electrical and thermal parameters from the manufacturer s specs can be seen on table 4 2 below 66 Max Syste
122. installed in the correct direction o IN OUT O ES Figure 7 1 Bridge Rectifier Secondly set the multi meter to the diode setting This setting is generally directly before the lowest resistance measurement setting The diode setting sets a potential between the test probes and measures the voltage drop through the diode This is much more efficient than simply measuring the resistance of the diode in multiple directions because the diode is not actually operating when the resistances are measured Last when the test probes are connected as shown The DMM will read either OL indicating an open circuit or a voltage of 0 7 volts DC or less Switch the DMM leads An operational bridge rectifier diode shows a reading opposite of the previous reading Perform this test on each adjacent pair of bridge rectifier pins The bridge rectifier is faulty if the readings are the same for any of the individual diodes 111 7 8 Voltage Regulator Testing LM79xx and LM78xx series regulators have built in thermal and over current protection and will limit output to a safe but hot level if the load is too heavy Although the voltage regulator is protected for overheat is good to check is the device is defective before we assemble the main circuit The following steps will help us determine whether the voltage regulator is defective or not Verify variable DC power supply is off Connect converter to variable DC power supply and multimeter D
123. ion precision acquisition price makes the ACS712 current sensor a very good candidate to be used in our system design Part specifications which support sensor efficiency are shown in below Table 3 1 ACS712 Supply Voltage 4 5V 5 5V Operating Temperature 40 C 85 C Bandwidth 80kHz Output Sensitivity 66 mV A 185 mV A Output Rise Time 5us Internal conductor Resistance 1 2 mQ Table 3 1 ACS712 current sensor key characteristics 47 3 9 2 2 MAX4172 Current Sensor MAX4172 is a high sense current amplifier ideally for systems where battery DC power line controlling is essential Sensor features a wide bandwidth ground sensing capability operates between 3 0V to 32V supply voltage in the Vcc and is available in a space saving 8 pin UMAX or SO package 38 In order to gain a high level of flexibility the MAX4172 works with an external sense resistor to establish the load current to be checked Additionally Maxim specifies that a user should expect only having a 2 output error at 25 degree C when sensors can fully operates from 40 to 85 degree C A detailed pin configuration to bring more information about how this current sensor could be integrated with our system is shown in below Figure 3 30 ______Pin Configuration TOP VIEW E maxim 7 r MAX4172 uMAX SO Figure 3 30 MAX4172 pin configuration Derived from Maxim Integrated MAX4172 Datasheet MAX4172 possess some advantages if the sy
124. ird voltage sensor will be placed between batteries and microcontroller in order to be able to check charging level and to display to LCD Once again resistors values R1 and R2 would be altered according our battery bank specifications 35 3 9 2 Current Sensors Current sensors are very important for this integrated energy harvest design since the project will implement a detail tracking of maximum power delivered as well as current reading Voltage measurement will be covered by the previous specified voltage sensors and then the current flow is desired to be captured as well Both current flows coming from wind turbine and solar panel will be analyzed processed and feed to microcontroller in order to display values on the LCD screen It was decided to seek for a prebuilt ready for production current sensor on the market rather than build a custom version to maximize the system efficiency Research came across with some possible solutions being our first one the Allegro ACS712 current sensor family MAX4172 from Maxim integrated and CSLA2CD clamp sensor from Honeywell 3 9 2 1 ACS712 Current Sensor The Allegro ACS712 is a practical and very well defined solution to measure AC or DC current in several industrial applications It is a fully integrated Hall Effect Based linear current sensor with a great voltage isolation of 2 1 kVRMS which it comes very handy to IRPS project specification 36 The ACS712 comes in a small surface ideally to b
125. ironment temperature Result would be saved in one variable to be further used in Charging Procedure Check PV This method will interact with voltage sensor linked to solar panel output to retrieve the current voltage status Result would be saved in variables to further use Check Wind This method will interact with voltage sensor linked to wind turbine output to retrieve the current voltage status Result would be saved in variables to further use Threshold Analysis In this step microcontroller will use previous two steps results to analyze at what mode IRPS should operate Integrated Solar Integrated Wind Independent Independent Wind Enhanced Also it will request information from temperature sensor to pre establish current threshold limits Current mode would be set at one variable for later use Charging Procedure This step is critical and hold a high degree of importance to maintain IRPS circuit stability and avoid board physical damage At this stage method will determine what source should be used and how It will read previously created battery objects and combining with decided threshold mode it will act upon the correct charging procedure Furthermore as an example if battery solar object need charge and it is at bulk charging stage battery wind object indicate full charge and threshold method define that IRPS should operate at Integrated solar mode then microcontroller will send the signal to solar charge controller sta
126. is microcontroller with a RF system on chip the system will obtain a result of CC430 family alternative for our project CC430 features a 32k flash memory 4k of ram 12 bit A D converter 16 ADC channels and integrated LCD driver for up to 160 segments and a very small size to integrate into our PCB The microcontroller itself is a very cheap solution but the downside here is that evaluation debugging board can reach the 100 and IDE to load the code has to be purchased as well for about 400 however free open source alternative software is available but not really the best option Furthermore Texas Instruments proprietary IDE has a free version with full capability but bears a limitation of 16 KB of total code Despites price to be invested on the software this MCU is considered as a good alternative because its features and low power consumption 3 10 4 PIC24 from Microchip Last alternative for microcontroller is the Pic24 family under a 16 bit architecture This family of microcontroller is compatible with high language C C and also could be accessible on assembly too The low power PIC24F performance at 3 3V and has from 64k to 96k of flash memory varying based on the version but either one leave plenty of room for algorithm code and necessary libraries The chip itself is very affordable for a few dollars and a point up to a very good 28 ADC inputs of 10 bit channels and despite his large pin size Pic24F comes with an efficient X
127. is fully charged the power will go to a diversion load to dissipate the exceeding power The voltage sensors will also be replaced to monitor the voltage level of the batteries so that the charging can take place automatically when it is needed All of the signals from the voltage sensors will be sent to the controller box which monitors the charging process of the battery bank Electricity will be drawn from the battery bank for power consumptions It will go through a DC AC converter and a transformer to the power outlet Charge Voltage A Controller sensor 7 Voltage sensor 3 f aTq AC Outlet Voltage Transformer sensor sf Charge Voltage Controller sensor AC Rectifier Figure 4 1 The Block Diagram of the Overall System 4 2 Solar Panel There are so many different types of solar panels in today s market but after much time spent looking the choice that is best for this project will be a polycrystalline silicon panel The mono crystalline silicon panels are more 65 efficient however the poly crystalline silicon panels are not that much less efficient Also the mono crystalline panels are too expensive for our budget and the extra bit of efficiency does not seem worth the extra money The thin film and amorphous silicon technology has not matured enough yet and has terrible efficiency compared to the silicon panels Although GaAs panels have excellent efficiency they have also been ruled out due to pr
128. is not used to charge the battery This type of algorithm is highly effective for a system that is using a valve regulated sealed battery 26 This is the type of battery that will most likely be used for this project therefore this type of algorithm will be the first one to be tested for the charge controller The last series algorithm is the constant current one This is a multi step algorithm that switches to a preset constant current rate to control the charging of the battery The battery voltage is then set to a specific voltage which depends on the chemistry of the battery The charge rate will then return to constant current linearly as the battery voltage decreases 27 The daily charge profile of the series linear controller can be seen below 25 1000 15 20 Irradiance lr Average 5 0 I Average Vay V Maximum V Average S a S47 V Minimum 15 es E u lt wW S25 00 q g 5 w iE lt w 9 Q 13 05 E lt g gt 500 00 gt 16 lt Ww lt E E T a 12 5 lt p in Y i 5 5 0 T T T T T 12 am 4am Bam 12 PM 4M Bem 12 AM 12 aM 4M Bam 12 Pm 4pm Bem 12 am TIME OF DAY TIME OF DAY Figure 3 8 The Daily Charge Profile of a Series Linear Controller Permission from American Technical Publishers Pending 3 4 3 Maximum Power Point Tracking MPPT Maximum power point tracking or MPPT is a technique us
129. is the output When a load is connected to the system the microcontroller will send the power stored to the supply the load However since most appliances use ac power the system has to invert the batteries VDC to VAC The main function of the inverter is to take 12V DC from the battery and step up the voltage to 120V and convert it to AC voltage The output of the system should reach between 110 and 120 Volts in AC power for the user to plug in electronic devices and use them The outlet should be safe for both the users and the electronic devices 5 2 Software Summary Controller box is the IRPS concept for the encapsulation of some components and functionalities IRPS will perform some actions directly related to microcontroller both in the input and output direction Controller box concept encompassed the microcontroller voltage sensors current sensor temperature 96 sensor LCD display and a USB interface An overall design of controller box is described in below Figure 5 2 1 poo wes6oid peog Voltage Sensor Ni lel ae Current Controller Sensor Voltage Sensor Voltage Sensor Voltage Sensor Figure 5 1 Overall Controller Box Diagram Depicted as the dark grey box in the middle of Figure 5 1 is the microcontroller chosen which was the Atmel AT91SAM7X512 with Netduino boot loader Orange box at the top left of diagram is describing the temperature sensor to be used in the IR
130. isplayed Display Status Algorithm conform correct Pending custom message to be displayed Table 7 1 Microcontroller Testing Plan Part 1 106 Step Procedure Expected Result Result Actual Microcontroller AT91SAM7X512 Part 2 10 Repeat Steps 2 5 8 using Each sensor should deliver corresponding sensors some reading and algorithms will perform Pending same result as 2 5 8 result correct charging mode 12 Repeat step 7 using step 10 Microcontroller will correctly Pending 11 result interact with circuitry to set correct charging state Repeat step 9 using 10 12 Identical result as step 9 result wilDevelopment phase PCB microcontroller integration a phase Table 7 2 Microcontroller Testing Plan Part 2 Expected Result Actual Result Step Procedure LCD 1 LCD connected to LCD and microcontroller Pending microcontroller should communicate effectively 2 Hard code values forming a Text ae on LCD ile a custom message 3 Conform alert message Table 7 3 LCD Testing Plan 7 4 Sensor Testing Sensors would be tested based on particular functionality parameters which will reinforce the assurance of having the components working at the top performance The goal is to detect factory defects or malfunctioning before sensors are implemented in IRPS PCB board The following tables contain each sensor that is going to be tested followed by the test plan that was estab
131. ively All of the data will be recorded and analyzed within the conclusion of this project 7 6 Storage Testing There will be two important parts of battery testing One of them is the testing of the time needed to charge up the battery from panel to fully charge This charging time will mostly depending on the output power of the solar panel and the wind turbine The other part of the battery testing is the time need for the battery will be the time to discharge The discharging time is essential to determine the maximum charge supplied to the inverter To test the charging time of the batteries the following steps will be implemented 1 Test the battery when there is no load in the system If the battery is connected correctly the charging process of the battery should start The voltage of the battery should then be checked by connecting a multi meter The multimeter should have the voltage reading that corresponding to the charging stage The current going through the battery should also be checked by using a multi meter The current reading should coincide with the charging stage current as well The time taken for the battery to reach the float charging stage should be monitored during the process The float charging stage voltage level and current level are referenced as the battery manual According to the battery and charge controller ratings it should take approximately eight hours 2 3 4 To test th
132. ki Wind_power 26 Hattington Ktech Corp Steve and James Dunlop Florida Solar Energy Center Battery Charge Controller Characteristics in Photovoltaic Systems IEEE AES Magazine Aug 1992 15 21 IEEE Explore Web 8 Nov 2012 lt http ucf edu gt 27 http www atperesources com PVS_Resources PDF ChargeControllerProfiles 28 Microelectronis Circuit Analysis and Design 4th ed Neamen 29 http services eng uts edu au venkat pe_html ch07s1 ch07s1p1 htm 30 Boost Converter Operation LT1070 Design Manual Carl Nelson amp Jim Williams 31 http www ti com lit an snosb84b snosb84b pdf 32 http ptm2 cc utu fi ptmusta kuvat elektroniikka mc34063 IEEEXplore pdf 33 http www linear com product LT 1160 34 http www windynation com articles charge controller wind turbine dump and diversion loads what they do and how choose right s 35 http oama ua edu bwbuckley projects mppt htm 36 http www allegromicro com Products Current Sensor Cs Zero To Fifty Amp Integrated Conductor Sensor ICs ACS712 aspx 37 MAXIMUM POWER POINT TRACKING qwiki com Retrieved 2011 06 10 38 http Awww dimec unisa it leonardo_new en mppt php 39 Hohm D P Ropp M E Comparative Study of Maximum Power Point Tracking Algorithms Progress in Photovoltaics Research and Applications vol 11 pp 47 62 June 2002 40 https Awww sparkfun com products 11021 41 http arduino cc en 42 http www microchi
133. le to set up the system ina remote location without any external power sources The controller box will be small in size There will be three or more LCD screens on the controller box to show the current live metrics of the system including the input voltage output voltage input voltage output current and battery charging status Users can monitor the system any time they want Moreover there will be buttons or switches for the user to turn on or shut down the system manually as desired Minimum connections will be kept to the controller box so that there will be little confusion at the set up process 2 2 6 Input 1 Solar Power Solar Power will be generated by a solar voltaic panel This is rapidly becoming a mainstream way to generate power in the commercial world as well as residential The main objective of this system is to charge and store energy efficiently into a battery Therefore the objective of the solar panel will be to help accomplish this task However the panel alone will not be the only component to complete this task The charge controller and voltage regulators attached to the output of the solar panel will play just as big if not bigger role than the panel itself With this aside the goal for the solar panel will be to research as many different types of panels and determine which one will be the most efficient choice for our region of the country 2 2 7 Input 2 Wind Power Over the last few decades renewable energy has s
134. lished for each type of sensor then the expected results and finally the status of the test 107 Step Procedure Expected Result Actual Result Voltage Sensor Build appropriate voltage Not time Solar sensor divider configuration consumed to Complete implement it Wind turbine Pending Batteries Pending Calculate appropriate resistor R1 MQ value Solar Sensor values based on the Solar R2 kQ value Calculated panel Wind Turbine batteries Vout lt 5 V in worst Wind Turbine and microcontroller specs case scenario Pending Batteries Pending Build each sensor circuit in Circuit simulated Solar Sensor Multisim output shouldn t Complete exceed 5V Wind turbine Pending Batteries Pending Build a voltage follower Vout must be Solar Sensor connected to low pass filter equal at the Complete desired point and lt Wind turbine Pending Batteries Pending Pending Expected Result Actual Result Current value would be Both readings have to Pending compared between coincide microcontroller reading and voltmeter Apply current value close to Sensor should hold while Pending sensor threshold current lt threshold Table 7 5 Current sensor Testing Plan 108 Step Procedure Expected Result Actual Result Temperature Sensor DS1624 Temperature sensor is Some output should be Pending connected to microcontroller received Sensor is tested room Both readings have to Pending temperature
135. lled input voltages This will allow for future knowledge of how the circuits will react to the non linear output voltage from the solar panel Once this is understood these circuits will be attached to the solar panel and tested outside on the UCF campus if the weather permits The solar panel needs to be tested to make sure that it has not been damaged in the delivery and that it is close to the manufacturers specs listed in the datasheet The first spec to be tested will be the open circuit voltage Voc According to the model s datasheet the SunWize SW S85P should have 22 0V for the Voc This can be tested by putting a voltmeter to the terminals on the back of the solar panel This is where some precaution needs to be taken A solar panel is always active when sunlight is present Therefore there is voltage running through the panel and it is enough to severely injure a person With this is mind the solar panel should be turned to a southern direction Make sure the voltmeter is on DC voltage and the probes are in the voltmeter inputs Put the probes on the voltage out terminals on the panel and take a reading While the voltmeter is reading the output voltage tilt the solar panel to the optimal angle with the sun 52 This should give a reading that is close to 22 0V for this panel Next the short circuit current Isc should be tested This will be tested again with the multi meter The multi meter should be set to DC amps and the probes mov
136. ly short coming of the AGM batteries is that they cost almost two to three time higher than the flooded batteries The battery chosen for IRPS is the Universal Power Group UPG UB12180 D5745 Sealed AGM type Lead Acid Battery shown in figure 4 11 The battery will be bought from Amazon com for 35 75 The battery is rated for nominal 12 volts and 18Ah capacity at a 20 hour 0 90A charge rate The battery has an internal resistance of 18 mille ohms and should be charged under constant voltage For cycle at 25 C the set point of the voltage level should be 2 45V per cell and the maximum charge current should within 0 30 C For standby at 25 C the set point of the voltage level should be 2 30V per cell and the allowable range is between 2 27 to 2 30 volts The final discharge voltage per cell is 1 75 volts The battery has the dimensions 7 13 x 3 01 x 6 50 cubic inches and weighs 11 9 lbs This battery has an average battery life of four years It can be used in security medical mobility solar emergency lighting uninterruptible power supplies electric gates or fences garage door backup battery and portable medical devices The battery will not leak even if it is broken and it can withstand freezing temperatures Moreover the battery also features small self discharge of 3 to 6 percent per month and no need for additional water It is efficient and reliable energy storage for this project 49 86 UB12180 Figure 4 11 Universal
137. m 250 to 400 Watts will work perfectly for our project These turbines vary in price from 130 to 400 This input power combined with solar energy will be enough to change the 12V battery bank and deliver the excess to load if the system has some components plugged in 3 3 4 Capacity and Production For this project it is important to know how much capacity wind power is produced in the US since the controller box can be utilized along with installed 19 wind turbines Capacity and production are two of the main factors that make wind power more attractive as an alternative source of electricity today According to the Global Wind Energy Council or GWEC the new global total capacity at the end of 2011 was 238 GW representing cumulative market growth of more than 20 an excellent industry growth rate given the economic climate even though it is lower than the average over the last 10 years which is about 28 21 In the United States the posted annual market growth of more than 30 in 2011 adding 6 810 MW in 31 states for a total installed capacity of almost 47 GW and cumulative market growth of nearly 17 While the US market struggles with uncertainty surrounding the extension of the federal Production Tax Credit PTC wind power is now established in 38 states and the footprint of the US turbine and component manufacturing industry covers 43 states This means that US manufacturers were able to supply about 60 of the content for the
138. m Voltage 600Vdc Series Fuse Rating 10A Voltage Temperature Coefficient 0 35 C Current Temperature Coefficient 0 065 C Power Temperature Coefficient 0 5 C Peak Power Tolerance 5 Table 4 2 Electrical and Thermal Parameters of SW S85P 47 4 2 1 Mounting Solar panels tend to be fragile and can easily be damaged if not properly secured One main reason the SunWize SW series was chosen is because of the mount holes premade on the perimeter of the panel Trying to drill holes into the panel could very easily destroy the panel so this was a good selling point on this particular solar panel The design for this project will need a ground based mounting bracket that can have the angle adjustable on the vertical axis Since this system is being built here in Central Florida which is the Northern Hemisphere the panel should face due south and have an optimal vertical angle This will allow the optimal amount of sun light for energy use Below is a table of these angles by month of the year for Orlando Florida 48 Month Jan Feb Mar Apr May Jue 46 54 620 e 0 70 coon Month Jul Aug Sept Oct Nov Dec 79 70 62 54 46 Sek Table 4 3 Angle of Vertical Axis on Mounting Bracket for Orlando FL 48 These angles could be controlled by a solar tracking system and would not have to be set manually This would require an electric motor which would need to be powered Since the main goal of this project is to charge the batteri
139. make Lead Acid batteries the most popular form in stand alone power generation at present The advantages are the following e Low cost The price of a 12 volts Lead Acid battery can be as low as 15 dollars while the average price of a Lithium lon battery is over one hundred dollars 49 e Lead acid batteries have the most matured battery technology 50 They are well developed and studied e Because of the ability to supply high surge currents lead acid batteries are able to uphold a relative large power to weight ratio Thus it is more efficient among all of the battery forms 3 13 2 3 Types of Lead Acid Battery There are two basic types of lead acid batteries starting and deep cycle battery The starting lead acid is designed to start a car and typically used in starting automotive engines They are lighter in weight comparing to deep cycle batteries This type of batteries achieves low resistance and high surface area by adding many thin lead plates in parallel This allows the batteries to have a maximum high current output The starting lead acid batteries are useful for applications that need a high current such as several hundred amperes to boost in relatively short period of time However it cannot be deep cycled The battery will be damaged if it is repeatedly deep discharged and it will lose its capacity as well 60 Continuous float charge will also damage the battery in premature failure On the other hand the deep cycl
140. matured and efficient 2 2 10 Output The output of the system should reach between 110 and 120 Volts in AC power for the user to plug in electronic devices and run them The outlet should be safe for both the users and the electronic devices 2 3 Project Requirements and Specifications The operation of the system is required to be able to produce steady output power and charging the batteries twenty four hours a day in spite of the variations of the solar and wind strength All of the internal components should consume as little power as possible Moreover the system must be safe both for the user to operate on and the appliances to work with There are three categories of specifications including power generation control box and power charge storage and delivery specifications The input and output of each component in every category are related with respect to the amount of power flow in the system The power generation specifications are shown in table 2 1 below Solar Panel Output Power gt 75W Open Circuit Output Voltage gt 12V Short Circuit Output Current gt 4A Weight lt 20lb Wind Turbine Output Voltage gt 12V Output Power gt 450W Generates power at gt 8mph Size Small Table 2 1 Power Generation Specifications The most important part of this project is the design of the control box It major parts of the control box are the microprocessor and the LED display The implem
141. more time By manipulating Ohm s Law equation equation 4 2 is derived as below Equation 4 2 Current Voltage Resistance Current Battery Bank Voltage Resistor s resistance 93 Plug in the values into equation 4 2 the current is then calculated to be 19 18 amperes Hence 268 watts power will flow through one of the WindyNation 12 volt dump load resistors It is important to make sure that the dump load are going to be used has the capacity of 268 watts at continuous duty to avoid dangerous fire hazard The WindyNation 12 volt dump loads have the ability to hold up to 312 watts of power continuously Therefore they can be used in this project As recalled the capacity of the dump load system is calculated to be 448 watts To use a 268 watt dump load resistor one way is to wire multiple 268 watt resistors in parallel Then the wattage of the dump load is the sum of each load Consequently the equation below can be derived Equation 4 3 Total Watts of the dump load system need to consume 268 watts x the number of 0 73 ohm resistors in parallel 448 watts 268 watts x number of 0 73 Ohm resistors needed in parallel Solve the equation above by using simple algebra the number of 2 9 Ohm resistors needed in parallel is calculated to be of 2 9 Ohm resistors needed in parallel 1 67 Since the resistors only come in whole units 1 67 resistors have to round up to two sets of dump load resistors for consuming 4
142. n programing against the LCD at the time of accommodating it increases the success of compacting all output reading in one LCD screen One possible disadvantage for both types is not having the potential to show images icons or create custom graphics interface 39 Last parameter to be analyzed over which LCD would be appropriate to use is the preference of having a monochrome or color screen Widely known is the fact that color screens are more expensive that their relative monochrome family then is almost certain that a monochrome version will be more suitable A third type of LCD being excluded by default because not complying with our targeting goals are the ones classified as Graphical LCD Even though this option is not being considered it is mentioned due to the fact that graphical LCD is greatly used nowadays on a large variety of user output information screen 55 Graphical LCD has to use more layers of cell to bring the rich appearance of colors which is equal to more power devoured from our harvested renewable energy Regardless of our project aim to maintain power consumption at the lowest it is given the credit that having a graphic LCD as user screen will potentially enhance user experience when interpreting the data shown not even limiting that making such LCD touchscreen capable will catapult application interaction to the next level Despite not being considered as an option it is leaving as a viable alternative to the
143. n project and would like to request permission to use three of your graphs in our documentation would like to request permission to use the Monthly Consumption of renewable and nuclear energy Jan 2003 Apr 2011 Monthly Consumption of renewable energy by fuel type Jan 2000 Apr 2011 and Monthly Electricity generation from nuclear and renewables Jan 2003 Apr 2011 from the following pages http www eia gov todayinenergy images 2011 08 01 nukerenewtop pn and http www eia gov todayinenergy images 2011 08 01 nukerenewelec png Please let me know if we would have permission to use these figures for a strictly academic and informational purpose in our project research documentation Thank you Sincerely Jing Zou Undergraduate Student Electrical Engineering Department University Of Central Florida RE Figure Permission InfoCtr OC lt INFOCTR eia gov gt Sent Wed 10 24 2012 9 41 AM To ingzou knights ucf edu Dear Jing Zou Thank you for your inquiry to the U S Energy Information Administration EIA concerning use of information on our website There is no copyright restriction on the use of those graphics Please see our reuse and copyright info at http www eia gov about copyrights_reuse cfm hope this information helps Please contact us again if you need further assistance with energy data and statistics Paul Hesse Z Inc Contractor to the Office of Communications U S Energy Informa
144. nces The production of electricity is not constant and cannot be predictable all the times Moreover if a wind turbine gets exposed for long periods to strong winds this can break apart the whole wind turbine and reduce production of electric power One major challenge to the industry of wind power generation is that to create enough electricity for a small community of 50 000 people they need to install hundreds of wind turbines How many wind turbines would be required to satisfy the demand of larger community for instance 120 000 people Space is a key factor that will always be taken into consideration when building new wind farms Some people argue that wind turbines when active produce high level of noise This can get challenging to solve when all wind turbines are combine to create wind farms However technology has improved wind turbines and now they are much more quiet machines Some other people think that wind farms are grotesque in form and shape They feel that the landscape is being changed completely by the creation of wind farms Natural view of countryside and coastal landscape are not enjoyable 17 because they are being corrupted by large and tall structures that never belonged to the country side 3 3 2 Wind Power Mechanism Generating electricity from wind is relatively simple All effective wind turbines often have 3 blades that are aerodynamically constructed to easily create a rotating movement as air blows The
145. ncy of a GaAs thin film solar panel is quite a bit higher than that of a CdTe panel GaAs efficiency averages around 20 to 25 with a record near the 30 mark 19 This is because GaAs as a semiconductor material has a nearly ideal band gap Like the other thin film types of material GaAs has insensitivity to heat thus helping the efficiency rating Not only is GaAs resistant to heat but it is also resistant to radiation This makes GaAs solar panels ideal for space applications However the disadvantages of GaAs far outweigh the benefits and will not be further pursued for this project 3 2 3 Photovoltaic Effect in Solar Cells To help make the decision of which type of solar panel would fit the needs of this project this paper will have to discuss how the solar cell actually works briefly Solar cells are made of semi conductors which respond to the sun s light The determining factor of how the semi conductor will respond is the band gap 13 Silicon or Germanium is the most common types used because they are abundant and engineers understand how they respond quite well The sun s light is made up of different types of light which have different energies levels There is the low energy infra red light the intermediate energy visible light and the high energy ultra violet light The Earth s atmosphere and magnetic field protect us from the harmful ultra violet light so solar panels on the surface of the planet don t need to worry about
146. nd turbine and a solar panel to operate under a load 42 Generally since wind turbines are used to charge battery banks or feed an electrical grid both of the applications need dump loads to consume the excess power The batteries in a battery bank will be charged until reach fully charged by the wind turbine Depending on the type of batteries that are used the full charge voltage could be up to 14 volts for a 12 volt battery bank Since overcharging of the battery can make permanent damage to the battery itself and may cause safety issues it is necessary to stop charging the battery bank when it is fully charged However the wind turbine needs to operate under at least one electrical load Thus a diversion load will be implemented to the system for this purpose 34 The control box will be monitoring the voltage of the battery bank The battery bank will be disconnected to the wind turbine or the solar panel when the controller senses that its voltage level reaches the predetermined fully charge voltage Moreover the control box will then switch the connection to the diversion load to keep the wind turbine or solar panel operating under a constant electrical load Once the control box sense the voltage of the battery bank drops under a pre set level it will switch the connection back to the battery bank This repeated process is essential for the health of the batteries the solar panels and the wind turbine since it can keep the battery b
147. nd more popular among all of the energy sources However due to the unstable and uncontrollable nature of natural resources relying on solar or wind source solely may not be able to produce enough power to meet the demand Moreover the performance of a solar or wind system independently can be quite inconsistent Therefore in general wind and solar are integrated together in a power system synergistically to improve the overall stability Nevertheless in reality it is difficult to charge the battery using both wind and solar energy at the same time This is because source impedances of the wind generator and the solar cell are very different Moreover wind and solar increase power system variability and uncertainty As a result the group is motivated to design a controller that will make the isolated integrated renewable power system more efficient and stable The goal of this project is to design a controller that optimizes the performance of an energy efficient standalone renewable energy sourced integrated power system The group s intention is to design a controller that is able to optimize the performance of both energy sources control the charging process and monitor the system in various conditions The microcontroller based controller will detect the instantaneous variations of both wind and solar source and then optimize the charging operation through proper charge controllers As a result the entire system of the integrated rene
148. nd status SBank_error or WBank_error will be set Moreover if both sub banks are found to be in error status then Storage Bank will output a No_bank status and an alert will be marked to be displayed later Third stage or Charging Procedure is the most complex in the functionality diagram In this mode controller box will check that Storage Bank is not at the status of No_bank because if this status is present then it means that both sub banks are found as unavailable Therefore controller box will emit the appropriate signal to close charging circuit to each bank and start deviating voltage coming to respective dissipative load If this check is successfully passed then next step will be to check if Threshold Algorithm is not at No_source status because there will be not voltage coming to the system Being at that state will means that even though Storage Bank is at some accepted status controller box will have to emit appropriate signal to close charging circuit to sub bank batteries to avoid losing any voltage coming out from batteries back to the source In the expected scenario where Threshold Algorithm is not at No_source status and Storage Bank is not at No_bank status then Charging Procedure will begin the valid logic of the stage First voltage value coming in from Threshold Algorithm will be compared with each sub bank voltage presented in Storage Bank and in case that first one is greater than any one on the second set
149. nterline 53 Air density has a significant effect on wind generator performance The power available in the wind is directly proportional to air density As air density increases the power available also increases Air density is a function of air pressure and temperature Published power curves are typically presented for standard conditions of temperature and pressure so they are readily comparable with one another At a standard temperature of 288 degrees Kelvin 273 15 degrees K plus 15 degrees Celsius and pressure of 760 mm Hg or 1013 25 mb air density is 1 225 kg m3 in SI units Standard conditions in the English system occur at a temperature of 59 degrees Fahrenheit and 29 92 in Hg Both temperature and pressure decrease with increasing elevation Consequently changes in elevation produce a profound effect on air density While changes in barometric pressure affect air density slightly temperature has a more discernible effect Air density decreases with increasing temperature 104 During the winter months average daytime temperatures in Orlando may average 70 degrees Fahrenheit 21 degrees C or more This can reduce air density by some 2 relative to standard conditions Consequently it s important to account for temperature as well elevation during power curve measurements There are several ways to measure power separately measuring voltage and current volts x amps watts or measuring voltage and current together with a powe
150. o ask for permission to use the profile graphs of the shunt and series controller I am not sure which book they came from but here is the website I found them at http www atperesources com PVS _Resources PDF ChargeControllerProfiles pdf There will only be one copy of my research report and it is just for the research on my project Thank you for your time and I hope to hear back from you David Wade Dwade5 knights ucf edu jdh AmericanTech net a vi 4 J David Holloway jdh americantech net A A A ations Monday November 19 2012 1 48 PM To dwade5 dwade5 knights ucf edu Thank you for your request You may use the materials from Photovoltaic Systems in your research project This is for single use and not to be distributed We appreciate your use of ATP publications David 9 Dawid Holloway Senior Vice President American Technical Publishers Inc 10100 Orland Parkway Suite 200 Orland Park IL 60467 5756 1 800 323 3471 708 957 1100 Phone 708 957 1101 Fax www go2atp com ie 220PM Creative Commons 1 the copyright holder of this work hereby publish it under the following licenses Sj Permission is granted to copy distribute and or modify this document under the terms of the GNU Free Documentation License Version 1 2 or any later version published by the Free Software Foundation with no Invariant Sections no Front Cover Texts and no Back Cover Texts A copy of the license is
151. ocontroller output pins implementation most of the pins will be assigned to specific functions First it is attributed the digital pins O and 1 to the LCD since it uses serial transmission such pins are better described as TX and RX and are part of the UART Auxiliary microcontroller will have another two UART pins located in digital pins 2 and 3 in case that an expansion is desire to IRPS and another serial transmit device is implemented Finally the four PWM output located at pins 5 6 9 10 will be controlling the circuitry logic focused in the charge controllers to implement the right stage of charging the addressing of voltage flow to batteries or dump the threshold energy source charging mechanism and all others function in the IRPS The Atmel AT91SAM7X512 microcontroller is a perfect election for IRPS since contain all hardware required and leave plenty room of processing and memory to add future expansions The natural choice with this microcontroller would be using AVR s IDE AVR Studio and programming language in this case code would be implemented in either a C like or in assembly language The principal deficiency with this alternative is the fact an external programmer is needed to load new code to the chip flash memory IRPS would use an enclosed chassis design to protect components then the situation of physically accessing to microcontroller every time that an update must be implemented it is highly inapplicable On top of previ
152. ocontroller unit selected will analyze both available sources to determine what would be the charging procedure at that moment such algorithm will be implemented with the aid of sensors to detect spontaneous discrepancy and to maximize battery bank charging This time two separate banks of batteries would be implemented first one named E jar and second Ewing for the sake of simplicity this project would use one battery representing each sub group The system would run under two main categories independent and integrated Integrated mode would be if sensor reports that only one source is available at the moment then microcontroller would analyze the data and send the proper signal to open corresponding circuit switches to charge both E lt olar and EwinaUsing one energy source Independent mode would be if sensors report that both sources are available and wind turbine is working under threshold limit then microcontroller will send appropriate signal to open corresponding switches allowing bank Esolar being charged with solar panel output and Ewinga being charged with wind turbine output A third mode an extension of independent is the wind enhanced mode which is not falling into a new category but rather improving it This special case is depicted as heritance from independent mode conditions with the addition of having wind turbine running beyond threshold limit 57 Furthermore the intention of this scenario would be solar panel char
153. olar array and the battery The series controllers like shunt controllers can be broken down into two different subcategories interrupting and linear The interrupting series controller typically will use a blocking diode for the switching element and the controller will open the circuit to terminate the battery from 24 charging There are many different algorithms for the interrupting series controller such as 2 step constant current 2 step dual set point pulse width modulation and sun array switching All these different algorithms essentially accomplish the same task inside the charge controller The daily charge profile of the interrupting series controller can be seen in the figure below irradiance lyr Average 5 0 m Average V V Maximum 800 V Average 14 V Minimum 15 v a D S S IRRADIANCE W m CURRENT A o o BATTERY VOLTAGE V a 3 ARRAY VOLTAGE V b an 200 11 0 12 am 4am Bau 12 PM 4pm 8 Pu 12am 12 am 4am Bam 12M 4PM 8 Pm 12 am TIME OF DAY TIME OF DAY Figure 3 7 The Daily Charge Profile of a Series Interrupting Controller Permission from American Technical Publishers Pending The second type of the series controller is the linear series The linear series controller has two subcategories which are constant voltage and constant current modified The constant voltage algorithm will dissipate the balance of the power that
154. onstant Voltage Method is the simplest of the three common MPPT algorithms This algorithm operates as a constant voltage value based of the open circuit voltage There is a range of accepted approximations for the operating voltage which in between 73 and 80 89 Figure 3 12 below illustrated the algorithm at a constant voltage of 76 of the Voc 29 Power Figure 3 12 MPPT Constant Voltage Method Permission from American Technical Publishers The constant voltage algorithm will temporarily set the solar panel current to zero to determine the open circuit voltage The operating voltage is then is then based of the ratio of the constant voltage to that of the open circuit voltage This is where the system will begin moving A specified time must be entered into the algorithm to tell the system when to isolate the source and begin the operation again 89 This method is not as efficient as the perturb and observe or the incremental conductance methods When the current is set to zero by the system significant losses of efficiency occur because so much energy is wasted The only advantage to this algorithm is that is much more simple and spends less time on the computations within the system 39 3 5 Rectifier Wind generators do not produce DC electricity so a device called a rectifier is used to convert the turbine s output current to DC This is the first stage in the battery charger circuit Some turbines have a rectifier built in In
155. or this purpose 119 e 11 solar panels 75 watt 12 V for a total of 825 W of power e 6 Battery 12V 7AH e Aconverter controller box capable of convert from DC to up to 1 5 KW of AC e The Derate Factor to convert form DC to AC was 0 770 e The primary load connected to the system was approximately of 1 5 Kw d with a peak of 63 W e The project life time was set to 30 years e The operation and maintenance was determined to be approximately a 0 5 of the initial investment per year Simulations are created for each state of USA taking into consideration the geographic characteristics for wind 55 and solar 54 Factors such as longitude altitude average altitude above sea level wind speed annual average and hour of peak wind speed are considered when simulating possible power output per state Figure 8 1 below shows the result of state of Connecticut as example Solar Resource Inputs File Edit Help oO HOMER uses the solar resource inputs to calculate the PY array power for each hour of the year Enter the latitude and Ss either an average daily radiation value or an average clearness index for each month HOMER uses the latitude value to calculate the average daily radiation from the cleamess index and vice versa Hold the pointer over an element or click Help for more information Location oe Latitude 41
156. ost size weight and technology maturity It is found in the research that lead acid and lithium ion chemistries are the most popular types of batteries for renewable energy systems Therefore a comparison of these two types of batteries will be break down into the above criterion in the table below Attributes Deep Lithium Cycle ion Lead Acid Depth of 75 80 Discharge Cost Low Very High Lifespan 1000 3000 Cycles Efficiency 72 78 100 Self Average Negligible discharge Energy 30 50 100 200 Density Wh kg Charge 12 16 1 4 Time hr Maturity of Mature Immature Technology Table 4 7 Lead Acid vs Li lon Batteries Currently the most popular type of batteries leading the battery market is the lithium ion batteries They are mostly used within portable electrical devices such as laptops cell phones and music players This is because they have very high efficiency of close to 100 percent and they have a very high energy density which stores a lot of energy for a small amount of weight In addition they have a lifespan of 3000 cycles at a depth of discharge of 80 percent Nevertheless they are very expensive therefore they are not currently considered for larger energy storage applications On the other hand lead acid batteries are the cheapest and most technological matured type of batteries Comparing to the li ion batteries they fit much better in the IRPS project in an economical manner Hence
157. ouble check connections of circuitry and equipment Power on variable DC power supply and multimeter Vary power supply through expected DC voltage range Check circuit for temperature Measure and record DC output throughout range of inputs Power off equipment before disconnecting The efficiency of a voltage regulator defines the percentage of power that is delivered to the load and is given by Pout Efficiency Pir 100 Note The steps above will help us testing the buck converter as well 7 9 DC AC Inverting and Power Output Testing By efficiency the actual meaning is the percentage of the power that goes into the inverter comes out as usable AC current nothing is ever 100 efficient there will always be some losses in the system This efficiency figure will vary according to how much power is being used at the time with the efficiency generally being greater when more power is used The efficiency of the inverter may vary from something just over 50 when a trickle of power is being used to something over 90 when the output is approaching the inverters rated output The inverter will use some power from your batteries even when you are not drawing any AC power from it This results in the low efficiencies at low power levels A 3 KW inverter may typically draw around 20 watts from the batteries when no AC current is being used It would then follow that if you are using 20 watts of AC power the inverter will be drawing 40 watts
158. ous disadvantage it is certainty that removing microcontroller can incur in further damage to board causing bending pins electrostatic discharge every time the chip is removed from a socket All combined will result an impractical deployment of IRPS controller box to a final scenario such as small location then the current approach is discarded as the best method to implement AT91SAM7X512 microcontroller Instead the Netduino development board procedure is chosen to implement algorithms in AT91SAM7X51 2 Netduino boot loader permits direct programming using USB interface removing the demand of a separate hardware to implement an update In consideration of this implementation a USB interface would be included in PCB design such as a USB to TTL integrated circuit IC would allow to update code in microcontroller after every components is integrated in IRPS PCB board A handy alternative is to use one ATmega8U2 reprogrammed as a USB to Serial converter to communicate AT91SAM7X512 microcontroller and IDE where is programmed the chip Second major fact supporting the Netduino method as microcontroller implementation is the available IDE and programming language The commodity of having the C language at hand to implement 76 microcontroller is a plus taking into consideration existent familiarity with language The language is both easy to use and robust sustaining all the functionality needed for interfacing with analog sensors 12C components
159. p com pagehandler enus family 1 6bit architecture pic24f html 43 http www altadox com Icd knowledge Icd_display_types htm 44 http learn adafruit com tmp36 temperature sensor 45 http www maximintegrated com datasheet index mvp id 2738 46 http www netduino com netduino specs htm 47 Spotnitz R Franklin J 2003 Abuse behavior of high power lithium ion cells Journal of Power Sources Elsevier 113 81 100 doi 10 1016 S0378 7753 02 00488 3 48 Coppez G Chowdhury S Chowdhury S P The importance of energy storage in Renewable Power Generation A review Universities Power Engineering Conference UPEC 2010 45th International vol no pp 1 5 Aug 31 2010 Sept 3 2010 49 http batteries batterymart com 50 K C Divya and J Ostergaard Battery energy storage technology for power systems An overview Electric Power Systems Research Vol 79 No 4 pp 511 520 2009 47 http www sunwize com index cfm page product_successstories amp crid 22 amp scrid 336 48 http solarelectricityhandbook com solar angle calculator html 49 http upgi com Themes leanandgreen images UPG ProductDownloads D5745 p df 50 http electricalplan blogspot com 2008 10 power inverter dc ac definition html 51 http www windynation com manuals 300 watt dump load 1 2 volt technical specification 52 http www youtube com watch v fkook28HhW 53 http www wind works org articles PowerCurves html 54
160. performance with minimal vibration Can generate 800 watts or more depending on PMA efficiency Manufactured using a precision injection molding process that produces blades of exceptional consistency Made with new thermoplastic to increase durability Smoother and more durable than any blades you can find in the market Adjustable blade degree with included degree adjusters shims see picture below High resistance to bending over 150 degrees 69 Voltage and Amp Curve Power Curve Charging 12V 100AH battery with SolarWind Hyrid Charging 12V 100AH battery with SolarWind Hyrid RX RX Controller Controller 35 600 5 25 HA Voltage ij Amp axe Power Voltage amp Amp Voltage amp Amp w fa oO 10 FEL L i o nd L L L o 500 1000 1500 2000 2500 o 500 1000 1500 2000 2500 RPM RPM Figure 4 3 Voltage amp Amp vs RPM P Generator Specification Table 4 4 Apollo 550W 12V D Specification 70 Figure 4 4 Apollo 550W 12V DC blade configuration Permission pending Body Specification Tail Height 225 cm 2 Upgradable TEC Table 4 5 Apollo 550W 12V D Blades specifications Permission pending 4 4 Controller Box Controller box is the IRPS concept for the encapsulation of some components and functionalities IRPS will perform some actions directly related to microcontroller both in the input and output direction However it is important to highlight
161. r or watt transducer AWEA s standard recommends though it doesn t require using a watt transducer Hall effect sensors and their signal amplifiers are found in clamp on ammeters They are easy to use You just pass the conductor being measured through the sensor doughnut The objective is to measure the generator s power after all internal losses so that only power delivered to the load is measured according to AWEA s performance standard In a battery charging wind system this occurs between the charge controller and the batteries as it is more recommendable In a real world application what is crucial is the energy saved to batteries not what s being produced at the top of the tower In a typical application battery storage is finite When batteries are fully charged wind generator charge controllers switch off the load to avoid overcharging and damaging the batteries Clearly it s futile to try and measure the wind generator s performance when the charge controller has stopped charging and unloaded the wind generator Consequently there must be sufficient load on the batteries so they never become fully charged during the test period This often entails a diversion controller and a diversion load Voltage is a good state of charge indicator for lead acid batteries Voltage decreases as batteries become discharged and increases as they are charged In a typical renewable energy system battery voltage constantly fluctuates with the state o
162. r square inch are the same as the 2 lay board 101 Min Qty 4 Boards White Legend 1 or 2 sides Lead Time 5 Days 1 Part Number per Order extra 50 charge for multiple parts or step amp repeat Lead Time 5 Days Max Size 30 sq inches Lead Free Solder Finish No Slots or overlapping drill hits Min 0 006 line space No Internal Routing cutouts Min 0 015 hole size No Scoring tab rout or drilled hole board separations All Holes Plated Routed to Overall Dimensions Max 35 drilled holes per sq inch Green LPI Mask Credit Card Orders Only Does not include Blind Buried Vias Table 6 2 4 Layer Printed Circuit Board Specification 102 Chapter 7 Project Prototype Testing 7 1 Solar Testing The group will spend time on the UCF campus testing the solar panel outside the Engineering building It is important for the group to understand how the purchased solar panel will react to different daylight hours and weather situations This can be observed by the output voltage of the panel during those different times of the day This will allow the group to become familiar with the fluctuations in the output voltage A direct power source from the senior design laboratory will be used to test the solar power circuits which include the power charger and voltage regulators This way the group can observe how the circuits are reacting to different types of contro
163. r threshold lever is needed for a cold environment Lower voltage threshold is preferred for safety reasons However to optimize the charge efficiency temperature sensors should be included to the chargers to adjust the charge voltage when the chargers are exposed to temperature fluctuations 49 Table 3 5 shows the advantages and disadvantages of different voltage threshold settings 63 2 30V to 2 35V cell 2 40V to 2 45V cell Advantages Maximum service life battery stays cool charge temperature can exceed 30 C 86 F Faster charge times higher and more consistent Capacity readings less sulfation Disadvantages Slow charge time capacity readings may be inconsistent and declining with each cycle Sulfation may occur without equalizing charge Subject to corrosion and gassing Needs constant water Not suitable for charging at high room temperatures causing severe overcharge Table 3 6 Effects of charge voltage on a small lead acid battery SLA 49 The sealed batteries have lower ability to tolerate overcharge than the flooded type Therefore it is crucial for this type of batteries not to stay at the topping voltage for more than 48 hours and reduce to the float voltage level For large stationary lead acid batteries it is recommended to set the float voltage between 2 25V per cell at 25 C Lower float charge voltage should be set when the battery is at temperatures above 29 C
164. race width and spacing The trace width of the PCB depends upon the maximum temperature rise of current and as well as the impedance tolerance The least width of trace and spacing are factored upon the x y rules X stands for the least trace width and y is the least trace spacing Tracing spacing is an important 89 parameter to discuss when trying to make a PCB It will tell the designer how to layout the traces width and spacing between the holes When a manufacturer makes a PCB he has to make sure that you are given adequate spacing so if the traces are adjacent to the holes there is a possibility that they will be shorted and therefore the board will be no longer good to use To calculate the spacing requirements one must determine the peak voltage and then plug it into the formula described below Spacing mm 0 6 Vpeakx0 005 Vpeak Vrms 2 41 2 in Volts Often when setting a workspace for the development of the PCB people must lay your board on a fixed grid called a snap grid This will function in order to make all the components on the PCB snap into their permanent positions on the grid Another grid to question whether a developer would want to use is a visible grid A visible grid consist of an on screen grid of solid lines or dots Here are some facts to bear in mind when working on grids for the design of PCB s 63 e A snap grid is crucial because the workspace for the PCB will allow the parts being placed on the
165. re 4 13 Two Dump Load Resistors Connected in Parallel Figure 5 1 Overall Controller Box Diagram Figure 5 2 Controller Box Block Functionality Diagram Figure 5 3 Algorithm Implementation Flow diagram Figure 7 1 Bridge Rectifier Figure 8 1 Solar resources entered to simulate power output for state of Connecticut Figure 8 2 NPV for systems on commercial and residential sector in each USA regional division and state 58 63 65 69 70 71 72 73 78 81 82 83 87 93 95 97 98 100 111 120 123 xvii Appendix D Tables Table 2 2 Control Box Specifications Table 2 3 Power Charge Storage and Delivery Specifications Table 3 1 ACS712 current sensor key characteristics Table 3 2 MAX4172 current sensor key characteristics Table 3 3 Typical application using CSLA2CD Current Sensor Table 3 4 Microcontroller Alternative Charging Modes Table 3 5 Key Battery Attributes Comparison Table 3 6 Effects of charge voltage on a small lead acid battery SLA Table 4 1 SunWize SW Series Polycrystalline Silicon Panels Table 4 2 Electrical and Thermal Parameters of SW S85P Table 4 3 Angle of Vertical Axis on Mounting Bracket for Orlando FL Table 4 4 Apollo 550W 12V D Specification Table 4 5 Apollo 550W 12V D Blades specifications Table 4 6 Temperature sensor DS1624 pin description Table 4 7 Lead Acid vs Li lon Batteries Table 4 8 UPG UB12180 D5745 Sealed AGM type Lead Acid Battery Specification
166. re for all design goals providing enough digital and analog pins to handle all sensors LCD and battery charging check meanwhile at the same time being able to control the IRPS circuitry using pulse width modulation PWM outputs A list of specifications for the AT91SAM7X512 is given below 40 32 bit microcontroller 48 MHZ clock speed 512 KB flash memory 128 KB SRAM Two pins UART 14 digital I O pins 6 analog inputs pins 4 PWM channels SPI Interface I2C bus communication Input power 7 5 12 V DC Output power 5 V DC The six analog pins would be utilized in IRPS In order to enable 1 C communication in this microcontroller analog pins 4 and 5 are going to be used Occupying two analog inputs will reduce the available number of analog inputs to four cause of IRPS will utilize two I1 C components DS1624 temperature 75 sensors One analog current sensor and four analog voltage sensors take up the leftover four analog input pins Every C device carries a unique address to allow a precise identification on the bus and up to 127 unique peripherals may be contained on a single 7 C bus Hence if any extra device needs to interact with microcontroller 172C compatible parts would be highly recommendable over analog devices In case that only analog device can be further implemented due to certain limitations then it is deemed necessary to include analog to digital converter in order to be in harmony with I7C bus In the micr
167. re increasing the conductivity of the semi conductor This will result in a disruption of the charge separation causing a lower voltage across the cell 14 However the higher temperature will cause the electron mobility to increase which will cause a slight increase in current but this is insignificant in comparison to the voltage loss The optimal environment for a solar panel to operate is sunny and cold temperatures Unfortunately for this system it is being built in an area that does not get cold often Some improvements could be added such as adding a coolant system to the back of the panel but this is costly and time consuming The temperature effect will have to be kept in mind for any inefficiencies that are noticed Most solar panel manufactures will include a temperature coefficient in the specs of their product to allow the customer to have an idea of the panel s efficiency in certain temperatures Figure 3 2 depicts the temperature effect on PV panels below 14 Current A N oO 0 0 1 0 2 0 3 0 4 0 5 0 6 0 7 Voltage V Figure 3 2 Temperature effect on PV panel performance with permission of solarpower2day net The last inefficiency is light absorption which was discussed in the earlier section The semi conductors can only absorb photons that have energy equal to or greater than their band gap This results in quite a bit of lost energy due to light having a different energy Many solar panel companies will engage in band g
168. rollers and PCB Testing Microcontroller and LCD test plan will be encompassed together based on the need of verifying data processed or calculated and the displaying of the same Current scenario will allow constantly debugging algorithm performance and correcting output Microcontroller test plan would be based on steps expected result and current status wanted from algorithm flow diagram Meanwhile same criteria would be applied to LCD test plan in order to assure the device functionality correctness In below Table 7 1 and Table 7 2 we can observe a detailed test plan for microcontroller consequently Table 7 3 will describe test plan for LCD unit Procedure Expected Result Actual Result Microcontroller AT91SAM7X512 Part 1 Netduino development board Proper functioning and In progress correctly functioning with programing code uploading necessary libraries Check Storage Hard code Algorithm take correct Pending decision based on value captured Check Temperature Hard Algorithm save entered code value or default one is assumed Check PV Hard code Algorithm save entered Pending value or default one is assumed Check Wind Hard code Algorithm save entered Pending value or default one is assumed correct charging mode Charging Procedure Algorithm will use previous Pending values to determine different charging states System Output Hard code Algorithm save entered Pending value to be d
169. se parameters in their spec data sheets which give the limits such as load currents losses set points and set point hysteresis values The set points are usually dependent on the temperature of the controller and the magnitude of the battery current 22 There are four basic charge controller set points which are Voltage Regulation set point VR Voltage Regulation Hysteresis VRH Low Voltage Disconnect LVD and Low Voltage Disconnect Hysteresis LVDH The voltage regulation set point is the maximum voltage that the controller will allow the battery to reach The controller will either discontinue battery charging or begin to regulate the amount of current being sent to the battery once this point has been hit 27 The voltage regulation hysteresis is the difference between the VR set point and the voltage at which the full array current is reapplied The greater this voltage span the longer the array current is interrupted from charging the battery If the VRH is too small then the control unit will oscillate possibly harming the switching element or any loads attached to the system 26 This is an extremely important factor to the entire system and will have to be monitored closely or the charging effectiveness of the controller will suffer The low voltage disconnect is the voltage point at which load is disconnected from the battery to prevent over discharge In other words the LVD is the actual allowable maximum depth of discharge
170. sh or the equivalent reduction in cash expenditures Negative cash flow designates an investment of cash or a reduction in cash receipts 58 In order to calculate de NPV we established a discount rate of a 7 which has been set by the US Department of Energy for this type of investment on residential and small businesses 59 NVP formula is described below n ACF NPV Dist 1 r i ACF stands for annual cash flow for each year that the project is supposed to be implemented To calculate the annual cash flow we used the initial investment along with the financing and tax credits that government has been giving on this type of investments The tax credit used was 30 of the total of net project cost on the first year 60 we also took into consideration the annual costs of operation and maintenance O amp M so the formula used was ACF ALP TxCr O amp M NES ALP Annual Loan Payment TxCr Tax Credit O amp M Costs of operation and maintenance 121 NES Net Energy Saving To calculate annual loan payments we used the PMT formula existent in excel which can be translated as follows ALP PVxi 1 Gow PV present value loan amount i Interest rate of the loan was used 6 for residential and 7 5 for commercial n loan term It was determined that annual costs of operation and maintenance was approximately of 0 5 of the initial investments with an inflation rate of 3 so O amp M cost were computed wit
171. shold Algorithm and Storage Bank Threshold algorithm mode will take both PV and Wind Turbine voltage sensor values and evaluate the strength of both results to determine if actual IRPS threshold status is classified as Integrated Independent or Independent Wind enhanced Previous statement is indeed asseverating that IRPS will use Mu Kuen Chen proposal where charging methodology will be designed using a microcontroller Therefore result will be established as No_ source Integrated_source Independent_source and IndependentWE_source Second mode to be implemented is Storage Bank where controller box will state what bank of batteries is available to be charged up IRPS prototype will implement one battery representing each sub bank but it is deemed that production version will have more than battery in each sub bank In the current mode if one or more sub bank follows the green arrows then it will mean that controller box will have at least one sub bank to look up at further stages Results will be established as All_banks if two are present Wind_bank if only wind sub bank is available and Solar_bank if only solar sub bank is available Whichever is the result it will be marked to be displayer later Contradictory if any of the sub banks is observed in error state due to complete discharge overcharge damage sensor not working properly or only connection missing then status will be marked to be displayed as alert a
172. sing purpose are Pins 1 and 2 SDA and SCL respectively which send data back and forth Serial Data SDA is the actual pin where data associated with temperature is send to the microcontroller once this information has been requested The microcontroller use previous configuration as it is shown in below Figure 3 33 to make the request for this information through this same pin The Serial Clock SCL is the pin that is responsible for clocking in and out the data that is sent through the SDA pin 45 DS1624 device comes with an identifier of 4 bit unique code which describes only this sensor to differentiate from others devices connected to C bus Moreover DS1624 have 3 pins 7 6 5 which are combined to create a 3 bit unique address assigned to each sensor to be included range from 000 to 111 giving a total of eight combinations as it was previously explained Therefore there is a well defined structure for microcontroller being able to communicate with different devices connected to I C bus and this case in order to reach each DS1624 sensor microcontroller will send an address first to identify which sensor is wanted and then will send the request These sensors have a high temperature tolerance from 55 to 125 C Despite of their market price around 9 DS1624 offers an attractive solution to implement using 77C bus and saving analog inputs for others sensors 51 DS1624 SDA a 8 Vdd SCL 2 7 3 6 Gnd 4 5 m
173. stem would work with high currents flow which it could be the case once the system starts to be designed Unfortunately this sensor only works with DC current limiting the flexibility of using it in all places where current is desired to be measured however its potential could be very helpful to be used on specific output where microcontroller is waiting for data to be analyzed displayed Part specifications which support sensor usability are shown in below Table 3 2 MAX4172 Supply Voltage 3V 32V Operating Temperature 40 C 85 C Table 3 2 MAX4172 current sensor key characteristics 48 3 9 2 3 CSLA2CD Current Sensor The CSLA2CD is an AC DC current sensor made by Honeywell which empowered the advantages of being a Hall Effect current sensor transducer One of its several advantages for this project is the fact that these types of sensors can be totally isolated from another high voltage electrical component eliminating risk of malfunctioning and help toward safety policies Previous asseveration is based on sensor functionality core of detecting magnetic field around the wire excepting any electrical contact between components This is a considerate benefit over current sensor using precision resistors 89 Second main advantage is that if our signal is weak and this cannot get the desired output the wire has to be looped as many times as amplification falls into expected range For the sake of example if our system o
174. stent and reliable solar and wind power system need to be developed One way to improve the overall performance of the system is by integrating those two energy sources together Monthly consumption of renewable energy by fuel type Jan 2000 Apr 2011 trillion btu 900 800 ahydro 700 a geo 600 thermal 500 biofuels 400 asolar 300 awind 200 biogenic 100 waste i mwood eia Jan 03 Jan 05 Jan 07 Jan 09 Jan 11 Figure 2 1 Monthly Consumption of renewable energy by fuel type Jan 2000 Apr 2011 Permission requested from the U S Energy Information Administration 2011 While integrating the two energy source together may seem to be more reliable of the single sourced system there still exist elements that will influence the 2 overall stability and consistency of the power system Therefore in this project the goal is to design a controller that can optimize the overall performance of an energy efficient standalone renewable energy sourced integrated power system 2 2 Objectives The primary objectives of the overall system are small scaled self sustained energy efficient environmental friendly low maintenance and user friendly All elements within the system such as microcontrollers sensors and monitoring electronics devices should consume the lowest amount of power as possible 2 2 1 Small Scaled The system will be small scaled and the purpose is to illustrate the idea of green energy production for
175. talled in parallel with the load resistor to reduce ripple in the output voltage Switched power regulators usually have high current therefore a capacitor must be chosen to minimize loss Capacitors experience a loss because of internal series resistance and inductance A good capacitor for this circuit must have good effective series resistance ESR and solid tantalum capacitors are best in this respect 29 Another way to achieve a low enough ESR is to parallel capacitors The diode in a switched Buck converter is also known as a free wheeling or catch diode The purpose of this diode is to always ensure that there is a path for the current to flow to the inductor It is necessary for this diode to be able turn off rapidly a fast recovery diode would be perfect for this application 29 To regulate the output with a PWM control an IC will be necessary The transistor switch will control the power to the load and a power MOSFET is more suited than a BJT 29 Transistors with fast switching times will need to be implemented to be able to handle the voltage spikes produced by the inductor 3 6 2 Boost Converter The boost converter or step up converter is used when the output voltage is greater than the input voltage Again like the buck converter the boost converter the inductor is used because it resists change in the current The biggest difference from the Buck converter is that the inductor is on the other side of the switch in series with
176. tarted to gain its ground Of all the different kinds of alternative energy sources available the use of wind power has been growing steadily Wind generators are available for homeowners in the market today most of them relative easy to assemble More homeowners chose to have a wind generator to work along with PV panels to make their system more productive To make a wind generator working efficiently homeowners also need to purchase some extra equipment necessary such as rectifiers to stabilize the output AC current charger controller to distribute the energy where most needed power divert and DC AC converter However among all these components the most important in terms of efficiency is the charger controller Most of the charger controllers nowadays are composed of either simple electrical components or are switch controlled systems These systems usually are wasting energy by distributing the excess current to the dump load or simply do not charge the batteries efficiently This design proposes a new way of managing resources by implementing microcontrollers with smart algorithms that charge the batteries faster and efficiently For this reason a wind generator was added to the design to show that combined with PV panels the smart controller will handle both sources smartly and efficiently 2 2 8 Control Box Control box is the project definition for the consolidation of microcontroller unit s and sensors which make possible to be knowle
177. tates last year and accounting for 14 billion in new investment According the report the percentage of wind equipment made in America also increased dramatically Nearly seventy percent of the equipment installed at U S wind farms last year including wind turbines and components like towers blades gears and generators is now from domestic manufacturers doubling from 35 percent in 2005 The growth in the industry has also led directly to more American jobs throughout a number of sectors and at factories across the country According to industry estimates the wind sector employs 75 000 American workers including workers at manufacturing facilities up and down the supply chain as well as engineers and construction workers who build and operate the wind farms 21 Technical innovation allowing for larger wind turbines with longer lighter blades has steadily improved wind turbine performance and increased the efficiency of power generation from wind energy At the same time wind project capital and maintenance costs continue to decline driving U S manufacturing competitiveness on the global market For new wind projects deployed last year the price of wind under long term power purchase contracts with utilities averaged 40 percent lower than in 2010 and about 50 percent lower than in 2009 making wind competitive with a range of wholesale power prices seen in 2011 Despite these recent technical and infrastructure improvements and con
178. tatus could be read in any lighting situation Backlighting makes the screen more versatile and allows the user to quickly and easily view the text in varying conditions Taking into account the arrived conclusion 20x4 characters LCD is chosen for implementation into the IRPS design This should provide enough room to display several quantitative values as well as any custom message or alert that need to be displayed The display model selected is the serial enabled LCD 09568 from vendor SparkFun Electronics shown in Figure 4 8 The actual LCD is 87 3 x 41 8 mm while the PCB footprint measures 105 x 59 9 mm This display is monochrome black on green and has adjustable backlighting Serial type LCD is selected over parallel similar models cause of their simplification of use and reduction in the number of pins that they use Parallel LCD device can be acquired at lower price but its added complexity at programming and the greater amount of microcontroller pins needed won t make up the money saving worth 80 45 4 Sensor Implementation 45 4 1 Voltage Sensor Voltage sensors to be used in IRPS system would be a voltage divider implementation along with a voltage follower to separate components and a low pass filter shielded final signal to avoid voltage spikes AT91SAM7X512 has a 5V tolerance and taking voltage directly from sources will peak over microcontroller threshold and cause system to overheat and fail Overall sensor design is described
179. ted project only have to make budget for the microcontroller components and development board because all software use to develop the code are free Moreover the community has developed very useful libraries to interact with sensors LCD communications and others devices having previous community support will ease the programming of algorithms and speed up the testing of our complete IRPS A picture detailing the Arduino Uno R3 board comes with a price of 29 95 which is on our budget range and it is a good guidance to follow at the time of assembling the final controller box design 3 10 2 Atmel AT91SAM7X512 Microcontroller AT91SAM7X512 from Atmel is featuring a very powerful ARM7 Thumb processor with high performance 32 bit RISC architecture Also AT91SAM7X512 performs at 48 MHz clock speed with an expansion of 20 GPIOS with SPI C and 4 PWM 42 An expansion of 14 digital I O pins and 6 analog inputs leave plenty room to decide if combine all monitoring process into one microcontroller instead having multiple units In addition the 512 KB space for code storage and 128 KB SRAM establish a comfortable condition to work with Since this unit possess 1 C bus communication it would be perfect if chosen temperature sensors are compatible with 72C too this would save analog inputs for others requirements As its relative but more discrete ATmega328 AT91SAM7X512 could be powered by an enhanced development board named Netduino This single
180. ted from the output of the charge controller When the battery has reached the fully charge the dump load should start to work The output of the charge controller should be connected to the dump load and the voltage across the dump load resistors and the current going through it should match the expected result calculated from section 4 11 113 Chapter 8 Administrative Content 8 1 Milestone Discussion The senior design project has been break down to two semesters of work In Senior Design 1 takes place from August to December 2012 the primary subjects should be focused on is defining the project conduction thorough research on related topics and proposing a complete design of the project All of these should be well documented for Senior Design 1 documentation Table 8 1 shows the research timeline of the project The research has been divided into nine sections Each of the members has assigned two or more sections A thorough research builds a good foundation for the design stage Research ao S D 2 v S ae P PS esl 5 es amp 8s z 2 22 5 88 58 8 8 2 a E gt g Sept 17 Sept 24 Oct 01 Oct 08 Oct 15 Oct 22 Oct 29 Nov 05 Nov 12 Table 8 1 Gantt Chart Depicting Research Timeline The second stage is the design stage The initial design will be conducted in the fall semester and slightly overlapping with the research stage According to each
181. tent and efficient Among the renewable energy related projects conducted by undergraduate university students almost 80 percent of the projects are on solar energy or wind energy alone Due to the intermittent and unpredictable nature of the renewable energy source depending either solar or wind energy source solely is considered unstable and inefficient Therefore it was decided to improve the overall stability and consistency by integrating the two energy source together A project conducted by a group of senior design students in University of Central Florida has involved in integrating renewable energy However their design involves human powered mechanism as one of the inputs 2 This will increase the system size and cost as a stand alone renewable power system Another disadvantage in this project is that the group did not implement an efficient battery charging algorithm This disadvantage will lower the overall efficiency and quality of the power system In addition another group of senior design students provided more insight to the maximum power point tracking for the solar system which satisfied the requirements of the university s senior design The format of this paper will be a reference of this documentation There is also a project that designed by University of Alaska Fairbanks The project is to develop a stand alone generation system for an off grid remote community in Alaska by integrating renewable energy sources with
182. the battery This could cause the battery to short circuit as well so a blocking diode will be needed in series between the battery and the switching element This controller type also requires a large heat sink to dissipate the excess power 26 The shunt controller can be split into two different algorithm types linear and interrupting The shunt linear algorithm maintains the battery at a fixed voltage by using a control element in parallel with the battery This relatively simple design is usually implemented with a Zener power diode which can drive the cost up and limit the power ratings of the controller 22 The shunt interrupting algorithm is a more typical use of a shunt controller by simply short circuiting the PV array to terminate battery charging Shunt interrupting method is also known as pulse charging 27 The figure below depicts the daily profile of the shunt interrupting controller 75 Imradiance hang Average Average a CURRENT A nw on gt IRRADIANCE W m BATTERY VOLTAGE V 3 ARRAY VOLTAGE V b n i r T 0 mir t T 12 aM 4 aM Bau 12 PM 4pm Bem 12 AM 12 aM 4am Baw 12 P4 4 PN 8 PM 12 am TIME OF DAY TIME OF DAY Figure 3 6 The Daily Charge Profile of a Shunt Interrupting Controller Permission from American Technical Publishers Pending 3 4 2 Series Controller The series controller uses some type of control element in series between the s
183. the method to calculate the characteristic impedance of a microstrip line The impedance of the microstrip line is altered with the frequency of the material being used The quasi static characteristic impedance can affect how the frequency rises or falls for the substrate 64 2 Bit sn St Za m i4 2 Mt 4h 14 4h palta microstrip On 21 Er Wet 11 Wer 11 Wer 2 91 h dielectric thickness W microstrip width Er substrates dielectric constant 4 8 DC AC Inverters There are basically three kinds of dc ac inverters square wave modified sine wave and pure sine wave The square wave is the simplest and the least expensive type but nowadays it is practically not used commercially because of low quality of power The modified sine wave topologies which are actually modified square waves produce square waves with some dead spots between positive and negative half cycles They are suitable for many electronic loads and are the most popular low cost inverters on the consumer market today Pure sine wave inverters produce AC voltage with low total harmonic distortion typically below 3 They are used when there is a need for clean sine wave outputs for some sensitive devices such as medical equipment laser printers stereos etc 50 A basic inverter design includes a transformer and a switch A DC current is driven through the center of the primary winding and the switch rapidly switches back and forth as the inductor ch
184. ther components 39 The simplest way to reduce a DC signal is to use a linear regulator in an integrated circuit IC form The most common types are the T0220 package which is a three terminal IC with the legs protruding from a plastic case with a metal back plate for bolting to a heat sink Figure 3 26 TO 220 transistor packages 3 6 6 1 78XX Three Terminals Linear Regulator One set of linear regulators that are commonly used is the 78XX three terminal linear regulator families where XX gives the output voltage of the regulator Both the input and output voltages of these regulators are positive For example a 7805 voltage regulator produces an output voltage 5volts For negative output voltages the 79XX regulators are available By adding additional circuitry fixed output IC regulators can be made adjustable Two common ways of doing this is are as follows a Adding a zener diode or resistor between the IC s ground terminal and ground If the ground current is not constant a resistor should not be used By switching in different values for the components the output voltage can be made adjustable in a step wise fashion b By placing a potentiometer in series with the IC s ground the output voltage can be varied But once again if the ground current is not constant this method will degrade regulation LINE VREG COMMON R3 Figure 3 27 A circuit diagram to make linear voltage regulator adjustable Electronics
185. tics 2 However the sun is an unlimited source of energy and the price has halved in the last decade and will continue to decrease as the technology to harvest it increases Furthermore solar power doesn t require us to mine raw materials which destroy the environment A terrible example of this is Canada s tar sands which is currently destroying the Boreal forest in Alberta which accounts for 25 of the world s intact forest It also creates toxic pools of byproducts that are large enough to see from space 3 Despite all of the advantages that solar power has there are just as many disadvantages that hinder solar power s use as a major power source The most obvious disadvantage is that solar energy cannot be harvested at night This is a big problem because during the winter months there are more hours of night than that of day Sometimes we are unable to collect the suns energy even during the day due to weather and atmospheric disturbances Another limitation is the inefficiency of the solar panels ability to collect the sun s the light Currently solar panel efficiency is around 22 which means a large quantity of surface area is required to produce a significant amount of energy 2 However technology is tirelessly improving this number and will eventually no longer be a limitation to solar power but at this time it must be listed as a disadvantage Another limitation lies in the storage process which has not yet reached its potenti
186. ting bulk charging mode to be effectuated and it will deviate energy to not charge the wind battery to avoid overcharging As protective trigger IRPS could be at any charging mode but if both batteries are full or unreachable for system to know current status then microcontroller begin to deviate the coming voltage to either Heat Sink or Dump Load System Output This method will request current IRPS output reading from sensor placed at that location Result will be saved in variable to be displayed on the LCD Display Status This method will compile all previous necessary variables and build a custom friendly message to be displayed in the LCD Important variables will be each battery charge status IRPS output reading and operating mode After this step microcontroller can be either put to idle mode for some period of time or directly jump to System Start flag 79 45 3 LCD Display As an important design requirement of the IRPS board is that the elements included should use as little power as possible as not to detract from the power available for charging the battery ARM microcontroller selected draws more energy that some smaller alternative but also reduce the chance of having to use two units instead of one and further complicate the logic of IRPS design Then it is decided to do some saving in energy consumed from others devices to be integrated therefore the graphical display was opted out On details a graphical display
187. tinued growth in 2012 the report finds that 2013 may see a dramatic slowing of domestic wind energy deployment due in part to the possible expiration of federal renewable energy tax incentives The Production Tax Credit PTC which provides an important tax credit to wind producers in the United States and has helped drive the industry s growth is set to expire at the end of this year The wind industry projects that 37 000 jobs could be lost if the PTC expires Working in tandem with the PTC the Advanced Energy Manufacturing Tax Credit provides a 30 percent investment credit to manufacturers who invest in capital equipment to make components for clean energy projects in the United States President Obama has called for an extension of these successful tax credits to ensure America leads the world in manufacturing the clean energy technologies of the future 24 3 3 5 Distribution of Wind Speed The strength of wind varies and an average value for a given location does not alone indicate the amount of energy a wind turbine could produce there To assess the frequency of wind speeds at a particular location a probability distribution function is often fit to the observed data Different locations will have different wind speed distributions The Weibull model closely mirrors the actual distribution of hourly wind speeds at many locations The Weibull factor is often close to 2 and therefore a Rayleigh distribution can be used as a less accurate
188. tion Administration EIA www eia gov To receive notifications of EIA data and report releases via email subscribe at http www eia gov tools emailupdates and or follow us on Twitter ElAgov NREL gov ae a a on D NATIONAL RENEWABLE ENERGY LABORATORY NREL HOME ABOUT NREL ENER S SCIENCE amp TECHNOLOGY I NAGU Roo eliS RGY SYSTEMS INTEGRATION Dynamic Maps GIS Data amp Analysis Tools SEARCH 4 NREL GIS Home amp Printable Version About NREL GIS Renewable Energy Webmaster Technical Potential To contact the Webmaster please provide your name e mail address and message below When you are Maps finished click Send Message NOTE If you enter your e mail address incorrectly we will be unable to reply Data Resources Data Visualization amp Tools Your name GIS Staff David Wade Publications Your email address Mailing List Dwade5 knights ucf edu Contact Us Your message To whomever this may concern My name is David Wade and I am an Electrical Engineering student at the University of Central Florida I am contacting you to ask for permission to use your Photovoltaic Solar Resource map of the USA for my senior design project on renewable energy I am researching and building a system that will efficiently distribute solar and wind power to a storage device Thank you for your time and I look forward to hearing from you David Wade Send Message Solar power information gt Inquiry John den Haan
189. to protect the semiconductor The laminate is becoming more commonly used in thin film panels making them cheaper and faster to produce because the entire panel is considered a solar cell There are many advantages to using thin film technology The laminate makes them flexible and easier to mount on uneven surfaces This means that thin film panels are also more durable from weather damage If a thin film panel is damaged it will still work at a lesser rate This is not true with silicon solar panels when one cell is damaged the entire panel will not work at all The use of laminate thin cells can also be more useful in residential applications because the traditional roofing materials can be replaced all together with the thin film panels This is possible because of how much less thin cells weigh compared to its silicon counterpart Thin film panels also work much better under hot conditions They will not lose nearly as much efficiency as the temperature 11 increases This makes thin film cells a good choice for hotter climates such as the Southwestern region of the United States Thin film panels also perform better than the competition in the shade and low light conditions However thin film and amorphous silicon also have some disadvantages The most significant of those disadvantages is their efficiency Thin film panels range around 4 7 efficiency 11 This means that more than twice as many thin film panels are required to produce
190. topping charge may sacrificed Lead acid batteries cannot be charged as fast as other types of batteries due to their lethargic nature There are three charge stages implemented by lead acid batteries They are constant current charge topping charge and float charge The first stage is the constant current charge stage also called the bulk charging stage This stage uses up approximately half of the required charge time The only requirement for this stage is that the charging voltage must be set to exceed the battery s current voltage The function of this stage is to discharge battery to around up to 70 of its capacity in about 5 to 8 hours The batteries that will be used in IRPS have 12V nominal battery voltage When the battery discharges below roughly 10 5V it can be permanently damaged Therefore it is important for the charge controller to monitor the status of the battery especially in this stage 49 The second stage is the topping stage This stage is important for the health of the battery The battery will lose its ability of being fully charged eventually if proper cares are not taken It begins when the voltage of the battery reaches a predetermined level and charges the remaining 30 of the battery in around 7 to 10 hours During the topping stage the battery at a lower current and the voltage saturates on a constant value The current decreases during the process because the internal resistance increases as the battery charges
191. trolling System 1 Call the board any name that you want 2 Make a net list file for your printed circuit board A net list file will tell the manufacturer in an organized fashion all of the listed individual components their numbered terminal ports and where they should be placed on the board 3 Next step is to define your board size in terms of width and height of the printed circuit board Make sure to choose a good width and height so that 102 you give yourself enough workspace to add more electronic components if necessary After that the PCB designer must select the number of layers that he wants for his design The designer can choose from 2 layers 4 layers or 6 layers 2 layers are mostly used for simple designs 4 layers is preferably applied for medium density designs and 6 layers mainly works for high density or complex designs 5 If the user designer determines that he would like to select either 4 layers or 6 layer PCB board then they have option for adding additional plane layers Plane layers are sheets of copper material 6 Subsequently the board has additional features such as coating for the PCB The designer can decide whether he would want a solder mask or a silkscreen Our best bet when designing our PCB is to use solder mask which is a green coating on the circuit board 88 7 Then there is an option of choosing which thickness is desired On the PCB123 software you can select either 0 031 inches
192. uch as possible therefore the current will also be affected by the voltage changes since they are proportional to the power level Some examples of the different modes of a voltage regulator are In buck mode the voltage decreases as the current 33 increases and boost mode the voltage is increased as the current decreases This way the power level will remain the same as it passes through the voltage regulator Some types of DC to DC converters that will be discussed in this research paper are Buck Converters Boost Converters Inverting Buck Boost Converter and Non inverting Buck Boost Converter 3 6 1 Buck Converter The Buck converter or step down converter is a very popular switch mode regulator The Buck converter can operate in three different stages The first stage the switch is on and the diode is off During this stage the inductor is acquiring energy because the source voltage is greater than the output voltage This causes the current to rise in the inductor and the capacitor to charge The figure below illustrates this stage of the Buck converter and has the equations which dictate the behavior of the circuit 2 V On State dvo E AE 2 dt C di VW Vo dt L Figure 3 17 On State of a Buck Converter with permission from Creative Commons During the second stage of the Buck converter the switch is off and the diode is on The current in the inductor freely flows through the diode and the energy in the inductor is giv
193. udy all of the types of materials used in order to make a good decision Both technology types can be broken into either mono crystalline or polycrystalline subcategories A common material used in making mono crystalline thin film panels is gallium arsenide GaAs Some materials used to create polycrystalline thin film panels are cadmium telluride CdTe amorphous silicon A Si and copper indium gallium selenide CIGS 8 3 2 2 1 Mono Crystalline Silicon Mono crystalline silicon panels are the most efficient and dependable technologies available in the solar panel industry This is because they are the oldest form of this technology and they have had the most testing 4 Mono 10 crystalline solar cells tend to be around 17 efficiency and the other types polycrystalline and thin cell are usually about 10 efficiency 9 This high efficiency means that mono crystalline silicon will get the most watts per square foot Since the design will be limited on space and require high efficiency mono crystalline silicon seems to be a good choice for this project However despite the high efficiency of this type of solar cell they can be very expensive Mono crystalline panels are also difficult to install because they are extremely fragile which can be an issue when the panels are being shipped to us as well 4 3 2 2 2 Polycrystalline Silicon Polycrystalline silicon as the name suggests is made of multiple silicon crystals molded toget
194. up fully charged 49 The third stage is the float charging stage The charging voltage is constant for this stage as well However the charging voltage is lower than the voltage level in the topping stage The loss of power caused by self discharge is compensated in this stage 49 Figure 3 36 illustrates the voltage and current level in each charging stage 62 Voltage per cell Charge current Stage 1 Stage 2 Stage 3 Constant current Topping charge Float lt lt po d O Voltage V Time hrs Figure 3 36 Voltage and Current in the three charging Stages Permission Pending It is shown in the figure that the transition between the first and second charging stage are seamless This transition occurs when the voltage of the battery reaches the pre determined level However the switch point of the current in between the first two stages is very clear The current decreases rapidly to three percent level of the rated current of the battery It is essential to set the correct charge voltage Compromises need to be made when setting the threshold voltage This is because it is desired for the battery to be fully charged to its maximum capacity in order to avoid sulfation while this may cause grid corrosion on the positive plate and induce gassing Moreover the battery voltage varies with temperature Marginally lower voltage thresholds are required in warmer surroundings vice versa a highe
195. ure 3 9 Solar Cell l V Curve in Varying Sunlight Permission from Creative Commons There are several common methods that are used to implement maximum power point tracking These approaches all vary on complexity based on the type of tracking they utilize The three most common types that will be talked about in this research paper are Perturb and Observe Method Incremental Conductance Method and Fixed Voltage Method 37 3 4 3 1 Perturb and Observe Method This method of power point tracking constantly checks the voltage or current depending on the system and continuing to increase the voltage as long as the power continues to increase 38 After the maximum power point has been passed the algorithm will notice the power dropping and start to decrease the voltage to compensate Figure 3 10 depicts the algorithm iterating over the power curve 27 Power W S Voltage V Figure 3 10 MPPT Perturb and Observe Method Permission from American Technical Publishers The main disadvantage of the Perturb and Observe algorithm is that it has difficulties when dealing with low irradiance This is due to the algorithm oscillating around the maximum power point which inevitably leads to inefficiencies Another disadvantage is when the power curve flattens out the Perturb and Observe Method has trouble determining where the maximum power point actually is located The final disadvantage to be discussed is that the algorithm has difficulty
196. ustion can also occur by some extreme conditions It may lead to unsafe circumstances when the cell is short circuited by deep discharging 3 13 3 2 Advantage Despite the cost and safety requirements Li ion batteries have a lot of advantages over other types of batteries e They have the best energy density which makes them have a very high efficiency of almost 100 e Self discharge rate for a li ion battery is negligible It is approximately 5 to 10 percent per month e The li ion batteries also have advantages on weight and size They are much lighter than other rechargeable batteries and have a wide variety of shapes and sizes which makes them fit in a large range of electronic devices 61 e The components of the battery are environmental friendly since the li ion battery will not release lithium metal 48 3 13 4 Battery Charging Algorithm There are various charging methods for lead acid batteries The battery charging process will be terminated when certain responses occur based on closed loop techniques that communicate with the battery Lead acid battery charging adopts a voltage based charging algorithm The charge time for lead acid batteries vary For sealed large stationary lead acid battery the charge time is 12 to16 hours It can be up to 36 to 48 hours However the charge time can be downgraded to 10 hours or less if the higher charge currents and multi stage charge methods are applied but the completion of the
197. utput signal is 0 05A and the signal needs to be strengthened then the cable is looped 10 times around sensor clamp and a reading of 0 5A will be obtained everything is done as previously stated and without having any heat dissipation effect since this types of sensor don t touch electrical element and never get hot Additionally Honeywell specifies that a user should expect only having a 2 output error at 25 degree C when sensors can fully operates from 40 to 85 degree C A typical application using this current sensor is shown below in Figure 3 31 HALL EFFECT CURRENT SENSOR Solar WIRING DIAGRAM MODEL CLSA2CD Power m 8 Volt DC Regulator LM7808C NOTE By using this product you agree to comply with all electrical code and safety guidelines Figure 3 31 Typical application using CSLA2CD Current Sensor Permission No everything is bright about this current for our project and some specs must be taken into consideration if it is decided to use this sensor in our circuit One consideration is the price of the sensor in the market which is tagged as 29 in Amazon as an example this price is considerably over what our project budgeted to spend in sensors taking into account that more than one would be used Also CSLA2CD describes a bulky size taking some considerable space in our pending to be designed board Part specifications which support sensor usability are shown in below Table 3 3 49 CSLA2CD Supply Voltage 6V 12
198. wable power system IRPS contains a solar panel wind mill control box battery bank and a power outlet to the loads In the overall system the wind turbine and solar panels will collect powers and feed them to the control box Then control box will send the inverted power to the battery bank for storage or it will pass the power and feed it directly to the load bus The wind power charge controller has a rectifier that will convert AC power which collected from the turbine into DC power and then store the power in the Battery Bank At the same time Solar PV panels have a different and separate solar charge controller This controller will control the power coming from the panels to the battery bank The batteries will supply electricity when the wind turbine and solar panel do not produce sufficient energy for the power consumptions Since most appliances and other house loads are usually run by AC power an inverter will be inserted to take DC power from the batteries and convert it to 120 volt AC Furthermore for the excess power that cannot be stored in the battery bank a dump and diversion unit will divert it to a resistive load Within the control box several features will be added to make the operation on the system more user friendly and will facilitate the testing process in this project Three LCD screens including a High Contrast LCD battery voltage High Contrast LCD turbine amperage meter and Battery status LCD will be attached
199. will continuously execute the sequence above and loop over it at same cycle time which is defined by the best execution model Above Figure 4 7 enumerate the main logical methods describing consequent steps to be implement however those main methods will use others sub methods serving as helpers Necessary sub methods are not present in flow diagram because some changes are expected when IRPS platform start to be developed All main methods and sub methods will be listed as table form after IRPS reach the prototype assembling phase and algorithm logic is considered close to final shape Currently methods describe in above Figure 4 7 will perform the following logic e System Start It is defined as the beginning of sequential flow it will be represented by an infinite cycle such as instruction While true and will 78 embrace the rest of the methods Also initial variables are supposed to be declared and initialized here Check Storage This method will check both battery banks status using the voltage sensors It will use two sub methods to check each corresponding battery Solar Wind After both batteries status have been retrieved all results would be saved in different battery objects belonging to battery class Some attributes to be recorded are current charge level current charge stage and if need more charging Check Temperature this method will interact with temperature sensor linked to IRPS output to retrieve current env
200. www solarchoice net au blog monocrystalline vs polycrystalline solar panels busting myths 11 BI Research 2011 Thin Film Photovoltaic PV Cells Market Analysis to 2020 CIGS Copper Indium Gallium Diselenide to Emerge as the Major Technology by 2020 gbiresearch com Retrieved 25 October 2012 12 http photochemistry epfl ch EDEY NREL paf 13 http infogreenglobal com the practical full spectrum solar cell comes closer more 2162 14 http www solarpower2day net solar cells efficiency 15 http www nrel gov gis solar htm 16 Thin Film wins PV market share Three New Plants in Germany Total Almost 50 MW Sustainableenergyworld eu 2009 03 14 Retrieved on 2011 09 13 17 abcdef The staus and future of the photovoltaics industry David E Carlson Chief Scientist BP Solar 14 March 2010 Retrieved 10 February 2011 18 X Wu et al October 2001 High Efficiency CTO ZTO CdS CdTe Polycrystalline Thin Film Solar Cells NREL CP 520 31025 19 http www azom com article aspx ArticlelD 1 166 20 http www renewablepowernews com archives 884 21 http www gwec net global figures wind energy global status 22 http www gwec net north america 23 http cleantechnica com 201 2 08 1 0 us reaches 50 gw of wind energy capacity in q2 of 201 2 bstX2X1 9x VWKhJBK 99 24 http energy gov articles energy report us wind energy production and manufacturing surges supporting jobs and 25 http en wikipedia org wi
201. x is ACS712 current sensor from Allegro which is going to be placed at IRPS output line current sensor will consume another analog input of microcontroller Dark green rectangle is representing the LCD display which is going to display every important reading produced from microcontroller and any last time message or alert LCD screen will be communicated with microcontroller through serial communication or more specific TX and RX microcontroller pins Lastly an USB interface will interact with microcontroller allowing updating program code USB interface will be represented by a USB to TTL integrated circuit Controller box possess a pre defined block diagram of how logically will perform as a whole Previous statement allows project development to be more 72 transparent and accessible to follow An overall controller box block diagram is described in below Figure 4 6 i E el Check Batteries Batteries el System Output Output _ ee Sa Sa ho Bank Charging Procedure Procedure LCD LCD Display _ Figure 4 6 Controller Box Block Functionality Diagram Controller box functionality diagram is shown in above Figure 4 6 and it is divided by using symbolical colors Blue boxes and arrows means logical stages and system direction flow Light oranges boxes are used to describe physical components which interact with some stages Red boxes and arrows are specially used to
202. zed by our microcontroller Having this sensor filtering the voltage before passing over microcontroller port will drastically reduce chances of damaging our system but one step more has to be taken to guarantee a complete safeness The component to be included would be a 5 1V Zener diode which is going to be placed in parallel to microcontroller Zener diode will control spikes in voltages caused by possible lightning which are very common in Florida as one of the 45 state region with more electric thunderstorm activity or any other reason that could make solar panels and wind turbine conduct over expected maximum capacity Zener diode will be our last resource to enforce a safe voltage to be given to microcontroller analog input Once our sensor emit a safe output voltage ready to be measured MCU will find itself ineffective to receive correct signal without having and analog to digital converter ADC which it will be a requirement to be present when discuss appropriate microcontroller for our hybrid energy system A second voltage sensor will be used for our wind turbine connected on series to corresponding input at Voltage Regulator and it will follow previous configuration and logic only changing resistors R1 and R2 values based on maximum output voltage specification dictated by our project wind turbine Final output reading for this sensor will use a second ADC port from microcontroller will be processed and displayed to LCD A th

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