SDMAY12-24 final document - Senior Design
Contents
1. U 26 oo sues IO OO UEM NNI UNE 27 SECTION 13 u l naa inva aei era eaae es 28 13 T 28 1 3 Ml cic 28 SECIION 14 AC LOAD kaa 30 SECTION 15 CONCLUDING REMARK S 31 ld M 32 APPENDIX A OPERATIONAL MANUAL oin iisa sedo eaae Sar e kai u Pino eda e eR 33 APPENDIX BT I _ _______ __ _______ 35 APPENDIX aaa Eaa Naa ure aus 36 APPENDIX 37 APPENDIX B l isAiksishiasasssaaapuawawaskuswiwkapasyawkypuyasasukaqwiwyasskasyawpuswssquswkuysywassha 38 APPENDIX B M 39 C M 40 APPENDIX 41 Page 3 SDMAY 1 2 24 final document Section 1 Revised Project Plan 1 1 Abstrac2. 13 MENO IV m 13 5 2 Available and 13 Design Delqllss DIN HEHNERRHEIHMURRUINEMIUNUIU DIU UIN DIDI MN EN 13 24 i SSD OG 13 SECTION 6 THREE PHASE POWER SOURCE 1 1 1 16 SECHON 7 MOTOR u n p u 5 MEAM MI TII RR NM IDEAS 18 SECTION 8 MOTOR AND GENERATOR MOUNTING 20 Be Ve New Motor ANQUDE ne 20 SIL l u nanan 20 SECTION 9 PERMANENT MAGNET GENERATQOR Q 1 22 SECTION 10 THREE PHASE DIODE RECTIFIER 1 1 1 23 0 re IM 23 28 CCU 6 23 SECTION 11 BUCK BOOST CONVERTER 24 he 24 ouo 24 ere c 25 SECTION 12 PULSE WIDTH MODULATIONN 26 Page 2 SDMAY 1 2 24 final document pue
3. Vsari Vpp VsarL Vss Vpp R R 1 0 1 pp 1 pp 1 1 909 f 2RC Page 27 SDMAY 1 2 24 final document Section 13 Battery Inverter 13 1 Batteries When there is no wind present a backup source is needed to power the load For this task the system uses two 12V batteries in series with each other This amount of voltage used is due to the minimum of 21V needed to be delivered to the inverter In order to prevent damage to the batteries the voltage level shouldn t exceed 26 volts or go lower than 17 volts A picture of the type of battery used along with the specifications is used in Figure 13 1 oo NOTSHORTONCUT d voip TOTALDISCHARGINO ID S re A BRALEDCON po yG i nEPLACEEVERY 3 5 eet WARRANT YAPPE S 2 of xp 7 ova 0 oh ges of heat nbov rene m MADE Figure 13 1 13 2 Inverter From the turbine or batteries a DC signal is sent to the inverter An inverter s task is to take a DC signal and send out the 60 Hz required AC signal to the load The input voltage ranges from 21 to 34 volts for operation For this reason the user needs to make sure the battery is above 21V for use of backup power to the system Figure 13 2 shows a picture of the inverter used and Figure 13 3 shows the specifications of the inverter used Figure 13 2 Pa
4. 2 DWG J N GND 1224 07 JQ 2 2222 o 15 V Outside PWM Box 1 GND 11 oP 15 V vduty 2 PWM D TB 10 15 V NI USB 6008 15 IM OCA 1 DWG 1224 03 AO 1 I TICN DWG DWG 1224 04 4 5 1 5 Vo 5715 TB 12 C 15 V B Af B 24 3 Small Wind Turbine Control System PWM Duty Cycle and Switching Frequency Control DRAWN BY CHECKED DATE SDMay12 24 4 30 12 SHEET NO 1224 02 Page 36 SDMAY 1 2 24 final document Appendix B 3 ON Inv x rt AC diagram DWG 1224 06 Inverter Switch Terminal Block TB GND Buck Boost DWG 1224 01 0O AC diagram _ DWG 1224 060 3 4 Switch Box DC 5 6 Buck Boost DWG 1224 01 a a m 8 Battery PWM 15 V ON 9 10 O OFF iind 3 pe DWG 1224 02 1 11 12 13 v 15 Vdc o DWG 1224 02 E3631A CT 15 V I 13 14 Batt Logic nd T DWG 1224 05 OCC 4O I dta FTN CT 15V DWG 1224 07 15 Vdc C 15 16 O DWG 1224 07 x Oy 2 NG 05 vc D 4 E3631A DWG 1224 05 20AFuse 7 123 20 Jumpers 12 or 18 AWG Small Wind Turbine Control System Battery Inverter Switches Term Block DRAWN BY CHECKED DATE SHEE 50 12 24 4 30 12 12
5. 5 NIMM A UNI 4 4 1 4 Functional Non functional Requirements 5 bur 6 BOSHE 6 SECTION 2 REVISED PROJECT DESIGN 7 2 1 EDUC 7 2 7 2 3 5 ENV HIE 8 20 SY NEM OS acini eu D DEUS 8 SECTION 3 IMPLEMENTATION AND TESTIMNG 9 BOLEE 9 3 2 Full System Testing and Implementqtion 9 3 3 Diode Rectifier Testing 10 3A Buck Boost Conyerter uuu 10 EINE 10 353 New Moro 11 SECTION 4 FUEL SYSTEM 12 SECTION 5 LABVIEW INTERFACE
6. SDMAY 1 2 24 final document Figure 8 4 The new motor and mount with the body of the turbine taken off Page 21 SDMAY 1 2 24 final document Section 9 Permanent Magnet Generator As we took apart the housing for the turbine we found that the generator used in this specific model of turbine is operated with a permanent magnet This is very common for small scale wind turbines While knowing the exact physics and equations behind this device s operation may not be critical to the operation of our small scale wind turbine system it is good to have some knowledge of its operation In this type of generator the excitation field is provided through the permanent magnet rather than through a coil Rotation of this permanent magnet which is normally done through wind power but in our case through the motor generates electric current in the coils surrounding the magnet Our generator outputs a three phase signal therefore the three phases are designed to be located 120 degrees apart in order to create the appropriate phase angles Page 22 SDMAY 1 2 24 final document Section 10 Three Phase Diode Rectifier 10 1 Overview The three phase output signal coming from the turbine generator is a variable voltage and variable frequency In order to produce a useable signal some conversion is required The diode rectifier is the first step in this conversion process This circuit takes the 3 voltage outputs from the generator and converts to o
7. After hitting the RUN button the system will maintain the stated slip and RPM Page 34 SDMAY 1 2 24 final document Appendix B 1 01 06 51 5201200 Turbine Generator Vi V2 NI USB 6008 02 NI USB 6008 05 AI 0 AI 0 AI 1 AI 1 DWG 1224 04 DWG 1224 04 C Q Q1 D7 GP10NC60HD STPS20120D x lt lt 3 3 mH 255 812 1 100 IGBT C OCA 4 DWG 1224 07 6 See Power Analyzer Schematics Small Wind Turbine Control System Turbine Generator Rectifier Buck boost 1224 03 5 OCB 3 IGBT G DWG 1224 07 DWG 1224 07 Mote All GND inside Rectifier buck boost is connected with jumpers i e they are tied together DRAWN BY CHECKED DATE SHEET DWG E 50 12 24 4 30 12 1224 01 35 SDMAY 1 2 24 final document Appendix B 2 Note GND is power supply COM Meaning the GND going to OCA 2 does not need to be connected 15 15 V with PWM Just COM R5 O R2 A A 100 A 4 OP J Vf switch _ 2 7 NI USB e a UM 6 _ 6008 14 A VU L THCN _ AQ 0 Ri DWG 47K 1224 04 C1 T 0 15 100nF 1 2 15 V AAA GND VV gt R7 lt 4 R6 330K lt 220K T GND
8. The electric motor used in this project is a 3 phase AC induction motor Specifically it is an Ironhorse MTCP 1P5 3BD36 motor purchased from Automation Direct in February 2012 Max Voltage Full Load Amps Full Load RPM Full Load Torque Locked Rotor Torque Break down Torque See www automationdirect com for more specifications An induction motor works by creating a rotating magnetic field using windings of wires called poles Each pole is connected to one of the three phase inputs The diagram below illustrates how the 120 separation of the power phases causes the generated magnetic field to rotate uniformly Picture Credit Wikipedia org This part of the motor which does not move is called the stator The input frequency to the motor can be used to change the speed at which the magnetic field rotates This speed is called the synchronous speed Since our motor has one pole pair per phase the synchronous speed is 60 times the input frequency That is a 60 Hz power input will produce a 3600 RPM synchronous speed The part of the motor that spins is called the rotor In an induction motor the rotor spins slightly slower than the stator It is called an asynchronous machine The slip of the motor is a calculation that represents how much slower the rotor is spinning f synchronous speed rotor speed slip synchronous speed Page 18 SDMAY 1 2 24 final document As the motor is loaded down
9. of the turbine is still intact in this old set up The turbine body plus the interior circuitry allows the center of gravity to move more in the turbine s direction causing necessary structure under the turbine generator This year s team SDMay1 2 24 has dismantled the body of the turbine and removed the interior circuitry We are then re building the circuitry so we have full control of the system see sections 9 12 By losing this extra weight and by adding a new motor that is approximately 60 165 we can reduce the amount of mounting materials needed We decided on a strategy that involves suspending the generator from the motor through a mount This can be observed in Figure 8 1 First let us focus on the coupling device used to attach the rotor of the motor with the shaft of the generator The black device in Figure 8 1 and 8 2 is the coupling We only needed to order half of the coupling that attaches to the rotor This was custom built to fit on the rotor of the Ironhorse induction motor Next we needed to make a quarter inch plate of metal that could attach the motor and generator Also the plate needed a hole in the middle where the rotor coupling shaft could fit through The grey plate in Figure 8 1 and 8 2 shows this mounting scheme The plate was made out of stainless steel and was cut to the desired dimensions The final motor mount Figure 8 2 Mount Grey and Coupling Black can be seen in Figure 8 4 Page 20
10. LabVIEW an anemometer Then LabVIEW controls the Ironhorse induction motor using the Kikosui 3 phase variable frequency drive or VFD for more on LabVIEW controls and measurements see section 5 The control of the motor follows the curve in Figure 1 1 Also the control of the motor depends on max RPM ratings and any changes in the load The control of the motor will use V Hz techniques and or slip techniques for more information on motor control see section 7 Next the VFD powers the motor to turn the rotor Through the coupling the rotor of the motor turns the shaft of the wind turbine generator The turbine generator then produces a 3 phase variable voltage and frequency see section 9 Now the variable AC voltage goes through a diode rectifier to produce a variable DC voltage see section 10 This DC voltage can now be regulated Figure 2 3 shows the regulated DC voltage batteries and inverter all connected at the same node red wire By understand Kirchhoff s Current Law KCL the regulated DC voltage the batteries voltage level and the inverter input voltage will be equal The motor will spin faster or slower depending on the speed of the simulated wind This speed of the motor or another way to say it the RPM s of the rotor determine the DC voltage coming out of the diode rectifier This DC voltage can either be too low for the batteries inverter nodes or too high To understand maximum and minimum levels of the batteries inver
11. manual explains the operating constraints of the inverter we use for this project We are using the model GTFX2524 Source 3 Southwest Windpower Inc Air X Owner s Manual Installation Operation Maintenance Flagstaff Arizona Southwest Windpower Inc October 2008 Owner s Manual This owner s manual gives operating constraints of the wind turbine that SDMAY 12 24 uses for their project We use the LAND model with serial number 117566 Source 4 Ryan Semler Shonda Butler Chad Hand Luke Rupiper Andrew Nigro sdmay11 01 Wind Turbine Design SDMAY11 01 May 2011 hitp seniord ece iastate edu may1101 index html This was the projects preceding team Phase Ill We are continuing from where they finished Using the devices that they put in place we are to meet our project needs Also to show how the current system is operating we will have to use their schematics that they designed Source 5 Trzynadlowski Andrzej M Introduction to Modern Power Electronics Hoboken NJ John Wiley amp Sons Inc 2010 Text Book This text book is used for an undergraduate class for electrical engineers EE 452 at ISU The information on the Buck boost can be primarily found in section 8 2 3 Source 6 Buck Boost Converter Wikipedia Wikipedia Foundation Inc August 201 1 http en wikipedia org wiki 2 80 93 converter Figure 11 1 was used from this Wikipedia site http en wikipedia org wiki Mandatory re
12. occurred then demounting and repair was needed with circuits that were considered to be in their final state i e mounted inside Plexiglas box Most of the time spent in this project was in testing and implementation This can be seen in the pie chart in section 1 6 Notice in Figure 3 1 how voltage and current measurements are taken from the circuit and fed back into the gate of the IGBT These green lines in Figure 3 1 are modeling the feedback system that is implemented into LabVIEW See section 5 for full development of the feedback system that controls the signal going into the gate of the IGBT This signal from LabVIEW passes through a PWM circuit section 12 then goes to the IGBT that is implemented in the Buck boost circuit see section 11 Figure 3 1 MATLAB PLECS Modeling Page 9 SDMAY 1 2 24 final document 3 3 Diode Rectifier Testing With the box setup the user just needs to plug in the three phases from the generator into the box plugs When testing the rectifier out the most important aspect is a clean DC output signal In Figure 3 2 the user can observe that the output is as desired Tek Auto 0 0005 MEASURE CH1 Duty CH1 Max 11 0 v CH1 1 Min 10 2 CH1 Freq CH3 Off Mone CH1 5 00 250 us CH1 7 1 20 Push an option button change its measurement Figure 3 2 3 4 Buck Boost Converter Testing The buck boost requires two wires designating the outp
13. 24 03 37 SDMAY 1 2 24 final document Appendix B 4 A1 GND AI 0 DWG 1224 01 C _ g V2 AI 1 AI 1 DWG 1224 01 Q C AI 5 AI 1 A N GND DWG 1224 05 O M 2 CT2 DWG 1224 05 AI 7 AI 3 GND Vf Switch PWM gt DWG 1224 02 S DWG 1224 02 GND O GN To DC Power Supply COM or TB 5 E2624A AI 4 AI 0 AI 3 AI 34 AO 0 Vduty AO 1 POO Batt Logic e OCC 1 PO 1 I DWG 1224 07 NATIONAL J WINSTRUMENTS NI USB 6008 0 9 50 Hamlin 55100 2 5 V i 4 5 V RPM Vdd Hamlin 55100 RPM GND Hamlin 55100 DRAWN BY CHECKED Small Wind Turbine Control System NI USB 6008 abMayl2 24 SHEET 1224 04 Page 38 SDMAY 1 2 24 final document Appendix B 5 Outside CT Box 15 V TB 14 0 15 DWG 1224 03 15 0 5 15 V TB 16 DWG 1224 03 Small Wind Turbine Control System CT Current Transducers CT 1 Current Flow R1 100 M 1 NI USB 6008 08 AI 2 AI 2 DWG 1224 04 7 15 V CT 2 E Current Flow 2 NI USB 6008 11 A 3 AI 3 DWG 1224 04 3DMayl2 24 DRAWN BY CHECKED Note GND is powe
14. SDMAY 1 2 24 FINAL DOCUMENT Wind Turbine Simulation Team Members Team Advisor Brian Alexander Cpr E Dr Venkataramana Ajjarapu Lon Bromolson EE Jarid Strike EE Chase Schaben EE SDMAY 1 2 24 final document DISCLAIMER This document was developed as a part of the requirements of an Electrical and Computer engineering course at lowa State University Ames lowa This document does not constitute a professional engineering design or a professional land surveying document Although the information is intended to be accurate the associated students faculty and lowa State University make no claims promises or guarantees about the accuracy completeness quality or adequacy of the information The user of this document shall ensure that any such use does not violate any laws with regard to professional licensing and certification requirements This use includes any work resulting from this student prepared document that is required to be under the responsible charge of a licensed engineer or surveyor This document is copyrighted by the students who produced this document and the associated faculty advisors No part may be reproduced without the written permission of the Senior Design course coordinator Page 1 SDMAY 1 2 24 final document TABLE OF CONTENTS SECTION 1 REVISED PROJECT PLAN Re ERFEY 4 ER tot AA PAAA VE 4 12s Customer
15. and additions needed to happen First studying the power system given was the key in obtaining a solution By Running simulations in MATLAB and using LabVIEW to measure power flow we were able to come up with some solutions Instead of feeding power from the turbine straight to the battery we decided it was best to send power straight to the inverter The problem is in the interior turbine circuitry This circuitry needs to see 7 volts to operate Because of this minimum operating Page 4 SDMAY 1 2 24 final document voltage of the turbine circuitry the batteries need to be in parallel to the turbine where the batteries supply the minimum operating voltage Upon researching different ways to increase the voltage we came across many different circuits We didn t want to use the circuitry already in place in the turbine so we decided to disassemble it and make our own circuitry After narrowing the options down we decided to use a buck boost converter see section 11 This circuit takes an input DC voltage and magnifies it to a level designed which in our case is between 21 and 34 volts see Inverter section 13 2 The turbine generator outputs a variable frequency sinusoidal 3 phase wave We want a single phase DC signal to be sent to the buck boost converter for best results so more circuitry would need to be pieced into the schematic The best way to go from a 3 phase signal to a 1 phase signal while converting to DC power is to use a
16. bVIEW Magtrol 6530 Power Analyzer Voltage level for each phase Input to LabVIEW Current level for each phase Input to LabVIEW Power calculations for each phase Input to LabVIEW Power Factor calculations for each phase Input to LabVIEW Frequency measurement Input to LabVIEW National Instruments USB 6008 Low Cost Multifunction DAQ PWM Frequency Output from LabVIEW PWM Duty Cycle Output from LabVIEW Battery Switch Output from LabVIEW Current measurements from CTs Input to LabVIEW Voltage measurements from voltage attenuators Input to LabVIEW Hall Sensor signal for RPM calculation Input to LabVIEW 5 3 Design Details The purpose of the LabVIEW software is to control the motor that is used to simulate wind control the PWM generator used by the Buck Boost converter and display measurements to the user The motor is controlled by setting the AC Voltage level and AC Frequency on the Kikusui PCR6000W2 The current implementation uses feedback control loop for this process where the actual RPM is compared to the synchronous RPM See the Motor section of this document for more details regarding motor control The frequency and duty cycle of the PWM generator are controlled using analog voltage outputs of the USB 6008 These DC outputs have a range of O 5V with 12 bit resolution and about 1 ms update latency The signals are ground referenced All of the ports labeled GND are connected to the same ground reference This refe
17. calibration by viewing PWM output on i oscilliscor The above block diagram shows a user input control value being converted from Duty Cycle to a Voltage Output value The voltage value is displayed on the indicator AOO and written to the USB 6008 with DAQmx More complicated graphical programming techniques are used to perform execution control of the Vis themselves combine measurements together calculate RPM etc Check on ni com isu for help with learning to use LabVIEW or e mail brian alexander ni com with any questions about the code used in this project Page 15 SDMAY 1 2 24 final document Section 6 Three Phase Power Source In this project wind power is simulated using an electrical motor that is powered and controlled using a variable voltage variable frequency three phase power supply The model of this power supply is a Kikusui PCR 6000W 2 It can be operated manually using the front control panel or through a GPIB connection It will measure the output current and power factor and calculate the Apparent VA Reactive VAR and Real W power levels This power source is adequate for controlling the induction motor as a variable frequency Drive VFD Kikusui currently provides software drivers for LabVIEW Visual Basic and LabWindows CVI The drivers allow the user to set the power supply voltage or frequency and read the measured power quantities into the host computer These software drivers cover the details of th
18. e underlying GPIB communication syntax Input Voltage From Coover Electrical System 230 V Single Phase Input Current From Coover Electrical System 48 A or less The output of the power supply must be set to 3 phase and the range should be set to 200V Setting the range to 200 input allows a user setting of up to 300V output See the product manual for more information Page 16 SDMAY 1 2 24 final document PCR 6000W2 Single phase three phase changeover type 1 2 3 4 5 1 VO slot to install an optional expansion card 2 The large color fluorescent character display tubes VFD allow a bright and clear display Operation is possible by using function keys or ten keys and jog shuttle combination The angle of the panel surface can be changed in 2 steps 3 Airintake port for forced air cooling equipped with a built in air filter 4 Power switch 5 Output receptacles 125 10 max 6 Input voltage range selector switch Only for PCR2000W and PCR4000W Page 17 8 9 7 Forced air cooling system exhaust port 8 Single phase output terminal board 170 to 250 V PCR8000W 12000W 6000W2 and 12000W2 however use only the 1 0 V to 250 V range 10 Single phase three phase selector this switch is equipped with a misoperation prevention cover 11 Single phase three phase indicator 12 Three phase output terminal board SDMAY 1 2 24 final document Section 7 Motor
19. ge 28 SDMAY 1 2 24 final document Nominal DC Input Voltage 24V Output Current Rating 20 8A DC Input Voltage Range 21 34V Figure 13 3 GTFX2524 Specifications Page 29 SDMAY 1 2 24 final document Section 14 AC Load The goal of the project is to deliver wind power to a certain load The load for this system is two light bulbs and an outlet An outlet is used if the user wants to simulate even larger loads than the light bulbs Our system is using standard 75 or 150 watt light bulbs and a switch that turns the second light bulb on or off All three of these loads can give an observer many possibilities for experimentation A picture of the load used can be seen below in Figure 14 1 Figure 14 1 Page 30 SDMAY 1 2 24 final document Section 15 Concluding This wind turbine simulation project is intended to be educational for those that implemented the system and for any future users If any of the discussed circuitry in the previous sections is damaged or incomplete upon use of the system please feel free to bypass or rebuild But any bypassing of circuitry must be done with prior knowledge of circuits and by studying this document Notice that any Plexiglas cases with circuitry are not mounted to the table The reasoning is for any potential user to implement their own circuitry to test their understanding of the system Disclaimer Any circuitry not discussed in the previous sections can be found in the schema
20. iangle wave This triangle wave when compared to a separate signal fed into the non inverting comparator creates a square wave T Figure 12 2 The triangle wave from the output of the inverting integrator is also known as a chopping or carrier signal In order to control the duty cycle of our PWM waveform we utilize an analog output from the NI DAQ to vary the command signal sent into the comparator as shown in Figure 12 3 Command modulating signal High Chopping carrier signal Page 26 SDMAY 1 2 24 final document Figure 12 3 The comparator circuitry is shown in Figure 12 4 Vin represents the input triangle waveform and represents the varying analog input from the NI DAQ that we use to control the duty cycle Vout 1 8 Vi 8V Z 4 1 8 V V Hysteresis R R Region VREF Figure 12 4 Refer to Appendix B 2 for the overall schematic of the PWM circuitry As you can see we use a modification of an inverting integrator The main modification we made was adding a transistor whose base is controlled by the square wave output the collector is connected in series to a resistor to the inverting input of the op amp controlling the triangle wave and the emitter is connected to ground This implementation ensures that the inverting integrator maintains an output between the control voltage and ground 12 2 Calculations 1 VsaTL VsaTH f RC
21. lations are controlled in a lab environment where the wind turbine is mounted to a table Because of safety reasons the wind turbine is not allowed to be placed on a building in the university Therefore the project is centrally located in a lab environment Since the turbine is controlled by an AC motor via coupling LabVIEW picks up readings from a wind sensor that is placed outside The reason for the wind sensor is to accurately simulate real wind conditions 2 4 System Updates The finalized system successfully achieves all of the goals described in the Revised Project Plan section Through rearrangement of circuitry the power from the turbine now flows directly to the inverter Batteries are bypassed unless the system needs the backup energy or when the batteries need charged The buck boost converter section 11 PWM section 12 diode rectifier section 10 and new motor mount section 7 8 were all added to the final system so the motor is the primary power source for the load Figure 2 3 and Appendix B shows the schematics and an overview of the new system Buck Boost Converter 4 Turbine Generator Induction Motor 3 Phase Power Analyzer load 120 VAC 60 Hz 3 Phase Variable Frequency Drive VFD Figure 2 3 Simplistic Model of Improved System Page 8 SDMAY 1 2 24 final document Section 3 Implementatio
22. n and Testing 3 1 Plexiglas Boxes All new circuitry sections 1O 12 and current transducers CT are incased inside clear Plexiglas boxes This allows protection of the circuitry and safety for the user All input and output ports are mounted with banana jacks on the casing of the boxes This is intended for easy wiring of the system Also this allows the user to make measurements at every input output 3 2 Full System Testing and Implementation Figure 3 1 shows a schematic of the system Before implementation of any hardware all testing was done through a MATLAB simulation First we would calculate the desired value of a passive device Then we would use that value in the MATLAB simulation and run a transient analysis After verification we would then order the part with the correct specifications Upon arrival of the part we would build a circuit prototype on a breadboard Next we would use multimeters oscilloscopes LabVIEW data or a combination of all three to verify earlier results seen through MATLAB Then the circuits would get soldered together and mounted in their designated Plexiglas box Finally a full system test would be conducted verifying all circuitry behaving as planned If at any point there was a device or circuit that did not meet expected results then we would go back to step one of calculations and repeat There were several times when testing the full system that devices would fail or become damaged When this
23. ne nearly DC output The output is nearly DC because there is going to be a reasonable amount of noise or ripple on the signal This noise is easily accounted for by adding a simple low pass RC resistor capacitor filter 3 phase source Figure 10 1 The figure above is the schematic for the three phase full wave bridge rectifier As stated before the wind turbine generator provides a three phase output which can be modeled as a three phase AC voltage source star wye connected In our application we are dealing with large amounts of current flowing through these diodes therefore we made sure to purchase diodes strong enough to handle these currents 10 2 Calculations There really is only one calculation needed when analyzing this circuit and that is the output voltage For an ideal three phase full wave rectifier the average output voltage is 3 V JV T lae Vay Where Vac Vav The DC or average output voltage The peak value of the sine wave The root mean Q firing angle of the thyristor In our case this is O because all diodes are used for rectification One additional calculation that is needed to be made is to find the cut off frequency of the low pass RC filter used to smooth the output of the diode rectifier roa l 1 Where Bio RC Fe AC W The cut off frequency in radians f The cut off frequency in hertz R Value of the resistor C Value of the shu
24. newable energy target http www prnewswire com news releases iowa leads nation in wind energ y generation 1 22435353 html http www allaboutcircuits com vol 3 chpt 3 4 html figure 10 1 Page 32 SDMAY 1 2 24 final document Appendix A Operational Manual WARNING This lab contains moving parts and high currents The user should always be accompanied with a lab partner when operating any equipment with this project The user and lab partner should inspect all wiring before operation The lab partner should double check any work pertaining to the user and any equipment operation Both individuals should have prior knowledge of circuits before handling any equipment Use this operation manual as a check off list when starting up the lab System schematics can be found in Appendix B l Check Wiring A Verify the wiring is correct by checking studying the schematics of the system B Ensure all banana plugs are in the correct slots and that plugs are fitting tightly T1 7 II Turn ON Inverter Switch Appendix B 3 A Now the system is connected to the inverter for DC AC inversion B Please turn the Inverter Switch OFF when done running the system C Trouble shooting l If Status Inverter light is OFF and Battery Full light is ON check Inverter On Off Jumper IV Turn ON 15 VDC Rail E3631A A The 15 VDC source is used to power the op amps and the CTs B WARNING Turning these on out of
25. nt capacitor Page 23 SDMAY 1 2 24 final document Section 11 Buck Boost Converter 11 1 Introduction to the Buck Boost The buck boost converter is the driving force of the circuitry After the voltage has been properly rectified from the diode rectifier Section 10 then the buck boost can start using the DC input voltage from equation 10 1 The buck boost is designed to either buck the voltage down or boost the voltage up This is ideal due to the varying voltages from the varying wind speeds The output voltage must maintain a range that is suitable to the load see Inverter section 13 Figure 11 1 shows the components of the buck boost Observe that the input voltage is the DC voltage from equation 10 1 and the load R is the inverter see section 13 The switch S is an IGBT transistor which is controlled through the circuitry see section 12 Figure 11 1 Buck Boost Converter V 42 11 1 1 4 Equation 11 1 shows the gain of the circuit where d is the duty cycle see section 11 2 Notice the negative sign which shows the output voltage is inverted with respect to the input voltage By simply connecting the wires to the buck boost in the appropriate manner one can disregard the negative sign 11 2 Technical Aspects The main driving force of the buck boost originates from the switching frequency fsw and the duty cycle d As seen from equation 11 2 the switching frequency can be defined as h
26. o measure the output voltage which is sent to LabVIEW through the NI DAQ 6008 Based on measurements LabVIEW decides on how to change the duty cycle through feedback loops When operating the buck boost with no load i e the inverter is off the PWM duty cycle can be reduced In doing so the output voltage will not increase exponentially It is only by electrically isolating the signals between the circuitry and the NI DAQ 6008 that measurements can be achieved The reasoning lies with how the NI DAQ 6008 has to be grounded and how the buck boost common ground inverts This can be achieved using an optocoupler see Appendix B 7 Page 25 SDMAY 1 2 24 final document Section 12 Pulse Width Modulation 12 1 Overview The operation of the buck boost converter hinges on a pulse width modulated PWM signal As explained earlier in section 11 the characteristics of this signal is what determines the output voltage from the converter There are many ways to produce a PWM signal We choose to use our knowledge learned in EE 230 and EE 330 by feeding the output of an inverting integrator into a non inverting comparator with hysteresis to create this square wave signal as shown in Figure 12 1 Varia Via Inverting Integrator MIN ting Cosrpraeaslus wth Hiysboroses Figure 12 1 The two separate outputs in Figure 12 1 are shown in Figure 12 2 As you can see the inverting integrator creates a tr
27. ow many times the switch S turns on and off per second Of course there is a limit to how fast the switch can turn off and on Most transistor data sheets have a switching frequency max The IGBT used in this project operates at a maximum switching frequency of 3 kHz As seen from equation 11 3 the duty cycle is a percentage of the amount of time the switch is on 1 11 2 lon lore t 2 11 3 lon lor Where Page 24 SDMAY 1 2 24 final document toy The amount of time the switch is ON t The amount of time the switch is OFF OFF Therefore by controlling the duty cycle to its appropriate value we can use equation 11 1 to properly control the output voltage of the buck boost Furthermore the inductor resistance directly impacts the gain of the circuit in the boost mode of operation Also the size of the inductor is limited by equation 11 4 In other words the inductance must be large enough to support the load and circuit parameter but not too large If the inductor is too large i e large resistance then the gain will diminish as the duty cycle increases This can be seen from equation 11 5 2 1 4 Ry 11 4 2f V 1 d Um L gt Where C the ratio of the inductor resistance to the load resistance 11 3 Controls The duty cycle and the switching frequency are controlled through the PWM circuit see section 12 In Appendix B 1 the circuit uses a voltage divider t
28. peed turbine will supply the battery bank when the batteries are below 24V Non Functional The project will be documented through technical manuals and in depth schematics The new motor will be remounted and be on a stable operating platform Page 5 SDMAY 1 2 24 final document 1 5 Budget Motor 175 Mounting Coupling 70 Circuitry 55 Hardware 50 Total 350 Budget 500 1 6 Schedule Time Deviation B Research Design mlmplementation Testing Documentation Page SDMAY 1 2 24 final document Section 2 Revised Project Design 2 1 Original System As stated in section one of this document the original system had the load powered by batteries The simulated wind energy was used to charge the batteries Figure 2 1 and 2 2 shows the project handed down to our group from the previous year E v Figure 2 1 Figure 2 2 Existing system from previous year 2 2 Intended Use The main purpose of this project is for future students to observe a small wind turbine system Since all experiments can be done in the lab area this creates a great learning environment Through user interface using LabVIEW a single user can monitor and if all goes as planned control the turbine system Even though a single person could maintain by his or herself the lab requires at least two individuals at all times in the lab Page SDMAY 1 2 24 final document 2 3 Operating Environment All simu
29. r supply COM SHEE 1224 05 Page 39 SDMAY 1 2 24 final document Appendix B 6 Inv DC Inv Switch TB 3 DWG 1224 03 DWG 1224 03 Ku Inverter AC Hot Qut an AC Neutral Out Small Wind Turbine Control System AC Diagram Inverter DRAWN BY 5 or 150 W _ Light bulbs Light Switch x CHECKED SHEET NO 1224 06 Page 40 SDMAY 1 2 24 final document Appendix B 7 Inside the Rectifier Buck boost box PWM D DWG 1224 020 GND DWG 1224 02 Batt Logic NI USB 6008 1 PO 0 DWG 1224 030 GND WG 1224 03 Small Wind Turbine Control System Phototransistors Optocouplers OC IGBT C DWG 1224 01 4 FODS817 IGBT G DWG 1224 01 IGBT E FOD817 DWG 1224 01 Logic go DWG 1224 03 Batt Logic DWG 1224 03 FOD817 DRAWN BY CHECKED DATE SHEET SDMay12 24 4 30 12 1224 07 Page 41
30. rectifier see section 10 From the use of a rectifier and a buck boost converter our inverter gets the 21 volt input it needs in order to power the load The next part of the system that needs revising is the use of the battery Since the battery is used as a secondary source of power it should only be in use when the wind is too low to power the system Also because we don t want to destroy expensive batteries they need to be charged when the voltage gets too low and also not exceed the 26 max voltage This can be done using a switch and LabVIEW to determine when the turbine needs to switch from powering the load to charging the battery or both Lastly since inexperienced users could be operating the system a simple easy to use LabVIEW interface will be in place This interface will assist in running the system as well as monitoring different voltage and current levels in the system To make sure users are running the system correctly there will be an operation manual to follow step by step start up and shut down instructions see Appendix A 1 4 Functional Non functional Requirements Functional turbine circuitry sections 10 12 will generate a 24V DC output turbine generator will generate a 400W peak output The motor will simulate outdoor wind speed The anemometer and wind vane will transmit wind profiles from locations on campus turbine output current will be accurate for the input wind s
31. rence should be the same as the common OV input to the PWM generator 5 4 Implementation Details All of the communication with the Kikusui PCR6000W2 and the Magtrol 6530 is done through a GPIB connection Both of these devices have LabVIEW drivers available from the manufacturer so the complicated details of the GPIB syntax is handled behind the scenes Page 13 SDMAY 1 2 24 final document Power Supply must have GPIB Address 1 The above block diagram shows a sequence of KIPCRL subVIs that configures the PCR6000W2 with predefined constants when they are executed Notice that the wires connect one block to the next A block will not execute until all of the inputs are ready This diagram executes in order from left to right gt KIPCRL Monitor used to monitor output conditions F P 4 3 i LE s RIPCFL L R IE ms EN Lil E This diagram shows several measurements that are taken continuously and then displayed on Indicators on the front panel Config Magtrol 6530 Config VI Read Magtrol 6530 Read VI All of the inputs and outputs on the USB 6008 are accessed through the DAQmx driver framework This is one of the National Instruments drivers It may be difficult to understand for new LabVIEW users DAQmx Start Task VI 4 DAQmx Write VI DAQmx Read VI DAQmx Stop VI Page 14 SDMAY 1 2 24 final document Conversion constants come from manual
32. sequence could cause device damage n Please turn the 15 VDC rail OFF when done running the system V Turn ON the 3 phase power supply Kikusui PCR6OOOLA A Read the Kikusui PCR6OOOLA manual on full operation Turn the Kikusui PCR6000LA OFF when done running the system VI Turn ON the power analyzer A Read the manual on full operation B Turn the power analyzer OFF when done running the system C When USB connection is plugged into power analyzer then the power analyzer must be ON for LabVIEW to connect to Kikusui PCR6000LA 3 phase power supply VII Turn ON the WESTPOINTE 4 fan A This fan is for cooling the IGBT heat sink in the buck boost Page 33 SDMAY 1 2 24 final document VIII Log into the project account with the correct log in password A For running an automated system using real wind data open file Wind Simulation FINAL Phase IV vi found on the desktop l Hit the RUN button at the top left corner B For running the system manually open file RPM Control2 vi found on the desktop l WARNING This manual LabVIEW file is for those that are familiar with motor control The user is advised to read through section Z on motor control in the final document of SDMay 12 24 Also the user should do any additional research required on induction motors Failure to do so will result in overheating of the motor and or damage to the internal windings 2 Here the user simply inputs slip and RPM of the machine
33. t As the United States pushes for green energy many wind turbines have popped up all around the United States With new forms of power it is essential for students to be educated on the effects of wind and the modern day power system The project described in this document takes wind measurements and simulates the power outputted to the system With a system already in place to accomplish this it was our job to improve upon the previous system 1 2 Customer Needs The smart grid simulation system must be capable of performing the following functions e Charge the battery bank using energy from the turbine when it is available e Power the grid using energy from the turbine when it is available e Power the grid using energy from the battery bank when the turbine is not providing power e The motor simulating wind speed needs to accurately reflect current wind speed conditions and the power generated should match the power curve of the turbine See Figure 1 1 POWER Power Output W mh 5 10 15 20 25 30 35 40 45 ms 23 45 68 9 0 113 135 158 180 20 3 Instantaneous Wind Speed Figure 1 1 1 3 System Plan The original system fed the power from the generator straight to the battery From there the battery fed power to the inverter and then into the load Since the inverter needs to have 21 volts to send power to the load they had two 12 volt batteries in series To improve upon the existing system some rearrangement of circuitry
34. ter node see section 13 Therefore we implemented a buck boost converter that can either boost the voltage up or buck the voltage down see section 11 The controls to the buck boost come from a PWM wave section 12 that is manipulated from LabVIEW commands Lastly when the desired voltage levels are met from the buck boost the inverter will turn on This means that the Status Inverter light is green When this light is green then at this point the user can turn on a light bulb if there is not one on already Page 12 SDMAY 1 2 24 final document Section 5 LabVIEW Interface 5 1 Overview Most of the components in our system interact with the host computer through National Instruments LabVIEW software This software allows a user to create a Virtual Instrument VI which may access various inputs and outputs of the computer These VIs have a front panel user interface to allow a user to control the system or observe measurements from the system The functionality of the VI is defined in a block diagram which connects various functions and sub VIs using virtual wires to define the data flow 5 2 Available Inputs and Outputs Arduino USB Serial Device Wireless Wind Speed Data Input to LabVIEW Kikusui PCR6000W2 Three Phase Power Supply AC Voltage level Output from LabVIEW AC Frequency Output from LabVIEW Current Input to LabVIEW Real Power Input to LabVIEW Complex Power Input to LabVIEW Power Factor Input to La
35. tics in Appendix B The system schematics are subject to change The schematics in this document are for understand the full system and how it works For completed schematics see computer col 301 sdmay1 2 24 in 1102 Coover Furthermore any devices or software that was not developed team SDMay 1 2 24 should have a user s manual see References where users should inquire for more detailed information Figure 2 2 shows the existing circuit that was implemented from last year s team Figure 15 1 shows the system rebuilt in its optimized format that was discussed in the above sections Notice the new motor mount with the generator exposed from the turbine The Plexiglas boxes show circuitry that was rebvilt from the turbine interior circuitry Not show in Figure 15 1 are the batteries inverter computer VFD power analyzer and 15 V supply Figure 15 1 Finalized System Page 31 SDMAY 1 2 24 final document References Source 1 Bishop Robert H LabVIEW 8 Student Edition Upper Saddle River NJ Person Education Inc 2007 Print Manual This manual is intended for those working in LabVIEW with the basics to more complex systems SDMAY12 24 group uses this manual to look up shortcuts implementing virtual instruments using MathScript etc Source 2 OutBack Power Systems FX Series Inverter Charger FX VFX GTFX GVFX MOBILE Installation Manual Arlington WA OutBack Power Systems June 2008 REV B Installation Manual This
36. ut the input and output voltage measurements and the PWM input to the circuit In order for this circuit to work correctly a DC output between 21 and 34 volts is required From the testing it has been determined that it does indeed work accordingly 3 5 PWM Testing Looking at the labels the box the user needs to make sure the plus and minus 15 V Vaa and Vss the input from the and the output cables are plugged in appropriately With different duty cycles the width of the wave gets smaller or larger As you can see below in Figure 3 3 the wave s output is behaving accordingly Tek Trig d Pas 0 0005 CH1 Coupling BW Limit Off 100MHz Voltage Invert CH1 5 00 250 us CH1 2 2 484 23 Apr 12 09 02 2 14534kHz Figure 3 3 Page 1O SDMAY 1 2 24 final document 3 5 New Motor Mount When we got the new motor we needed to make sure our power output from the generator was matching the power curve in Figure 1 1 LabVIEW is used to control the voltage levels to the motor for simulations and we adjusted the voltage inputs to model the correct output power Also with a new motor comes a new mount see sections 7 and 8 The new mount keeps the motor and turbine stable with little oscillations to prevent energy losses Page 11 SDMAY 1 2 24 final document Section 4 Full System Overview Refer to Figure 2 3 for the system overview First the computer col 301 sdmay 1 2 24 takes in real wind data through
37. with torque the rotor speed will decrease causing the slip to increase This effect can be counter acted by increasing the voltage to keep the slip around 1 5 If the load torque decreases the voltage should be decreased as well in order to prevent the windings from being overcharged A simple method to control the motor speed involves measuring the rotor speed and adjusting the input voltage so that it is slightly less than the synchronous speed Simple motor control example Desired Rotor Speed 1000 RPM Desired Slip 0 03 3 Synchronous Speed 1000 1 0 03 1030 9 RPM Power Supply Frequency 1030 9 60 lt 17 18 Hz Adjust supply voltage so the measured rotor speed is close to 1000 RPM When the load torque changes the voltage should be changed to maintain 1000 RPM rotor speed Page 19 SDMAY 1 2 24 final document Section 8 Motor and Generator Mounting 8 1 New Motor Mount Due to the low power output of the previous motor our group found it was necessary to obtain a new motor that could handle the load See section 7 for more details on the Ironhorse 1 5 hp induction motor The dimensions of the new motor are different from the last motor Therefore we acquired new strategies in mounting Figure 8 1 shows a depiction of the new motor and the mount This CAD drawing was done using Sketchup 8 Figure 8 1 New motor mount 8 2 Strategy Figure 8 3 shows the old motor and mounting scheme Notice how the body
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