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Electric Drives Lab Manual - Electrical and Computer Engineering

1. x EB expt arabe i Size Type Origin Description H E Model Root finalTime ixi FloatIeee Simulation 1 f Labels currentTime ixi FloatIeee Current si E Task Info modelStepSize ixi FloatIeee64 Fixed step simState 1x1 Int32 Simulation errorNumber 1x1 UInt32 Error num rti amp ssertionMode 1x1 Int32 Assertion 4 4 P ef Log Viewer A Interpreter A File Selector A c documents and settings 2 270 desktop exp1 exp1 sdf For Help press F1 EDIT INUM 06 07 2007 18 29 ifstart or SG Amana Simulink Library GypandoraBox Cytnduction motor Wiese e ControlDesk D SF 6 29PM Figure 1 8 Control panel layout i ControlDesk Developer Version exp1 8l x bz File Edit View Tools Experiment Platform Instrumentation Parameter Editor Window Help 81 x jzssu sme2csv es S s S mm 1e low s s ejj8ezaejgss xme e a 4 IEEE Animation mode 500 500 1 0 1 PLAY green TOW 400 400 08 I Capture Settings Window ds1104 expl X z 300 300 rd PPE expt HostService z oe 200 p 200 5 S 100 His EZ Lengn 4d a far D 01 z 5 02 7 5 o v Auto Repeat Downsampina 14 Ei D 5 Trigger Signal g 100 nm E o cw z 100 l 4 4T Thy PPC exp1 HostService 200 8 4 0 2 ao 9 400 30 04 500 400 0 6 D E n r 0 10 20 30 Reset Value Speed Measurement _mech RPM
2. Plotter speed rpm Out1 1 0 3 1 tt 3i Ii 000 0 002 0004 0006 0 008 0 010 0 012 0 014 0 016 0 018 mes J 000 0 002 0004 0 006 0 008 0 010 0 012 0 014 0 016 0 018 Figure 3 3 Layout files for measurement of kg 3 3 Determination of Ke Open Circuit Test The back emf that is generated in the motor is directly proportional to the speed of the motor Equation 2 In this section the MUT 1s driven at a certain speed by another motor in this case a DC generator running as a motor The open circuit voltage Ey is measured using a DMM For 10 different values of speed from 0 rpm till around 2000 rpm measure the value of E Enter this in Table 1 Plot these values in Matlab and find the slope of this line kg NOTE Do not exceed V Ai B1 20V 2000 rpm Ep o kg 2 Table 1 Take 10 readings from 0 to 2000rpm Motor Speed RPM Measured Eb 30 3 4 Determination of electrical parameters Blocked Rotor Test V Rala kgo La 3 To estimate the armature inductance the motor must be held a standstill w 0 If the rotor is blocked and a step voltage is then applied to the armature terminals the current increases exponentially in time and equation 3 becomes dig Va Rala La dt 4 The solution for this differential equation is 5 Va t hs e 5 L Where T Ra
3. DS1104 ADC C5 motor current PWM Control Avg Block Enc position Enc delta position 2 pi Ts 1000 Wnm dist Wm DS1104 ENC POS CI motor speed Encoder Master Setup DS1104 ENC SETUP Figure 5 7 Simulink model for real time implementation of DC motor control 57 d e dSPACE I O Board Figure 5 8 Connections on the board Remove the DC motor mask model and gain Kpwm block Copy and paste the duty cycle calculator from the Simulink model used in previous experiments The current and the speed are to be measured For measurements use the blocks already designed in previous experiments Replace the speed ref wm ref step and sum block with a constant block for setting the speed reference e Atthe Matlab prompt set the sampling time Ts 0 0001 and the dc bus voltage at Vd 42V Also set the values of various variables you have defined in the model e Set the Simulation Configuration Parameters Solver Start time 0 Stop time inf Type Fixed step Solver odel Euler Fixed step size 1e 4 58 Optimization in Simulation and code generation uncheck everything except Implement logic signals as Boolean data Real Time Workshop System target file rti1104 tlc e Fig 5 7 1s then the simulation block for DC motor control Make the connections on the board as shown in Fig 5 8 The block wref 4quad gives a periodic step change in reference
4. x N 100 syn e Reduce the torque back to zero Now set ref frequency to zero so that the machines come to rest Stop the experiment in the edit mode 8 5 Determine Lir Lis R If we run Induction machine at slip 1 and assume that Lm gt gt Lir then joL fior R js joL R The equivalent impedance seen at machine terminals becomes je Li Lis R T Rg Further assuming that Lis 2 3 Lir and knowing the value of Rs we can calculate Lir Lis R 86 e In the capture setting window the length is set to 0 8s Goto Animation mode and check slip v f Control so that the frequency and magnitude of the IM voltages can be controlled independently The DC machine will run under speed control mode with reference speed equal to zero which is 1n same as blocked rotor Slip v fControl Torque SpeedControl e Increase the value in the ref frequency numerical input box to fai Hz in small steps Now increase Vsp while observing the ia imotor Waveform till the rms current reaches the rated current of 4 54 e Save the waveform from ControlDesk as vi_blocked mat Enter the peak value of the induction motor phase a voltage and current and the time difference between the zero crossings of the voltage and current waveforms in the Matlab file The computations carried out are Lms I V2 Va W v2 0 At x 2nf gin V Zo E Iss X n 1mag Z eni l
5. 0 6 Length 2 Iw Auto Repeat Downsampling i Trigger Signal v n lf E Level 0 5 Delay 0 iM odel Haat 5D AM alue Reference Capture Capture Variables Take ave re 003 of OOS Figure 4 7 Capture Settings 4 5 Lab Report 0points Make sure to include plots tables with captions Use proper units eg R 10 ohm Show the steps used in calculations for Questions 4 7 l a Plot the torque speed characteristics of the DC motor and load motor 2 graphs Section 4 2 4 2points b Comment on the torque speed characteristics in terms of when is the maximum power available for a given voltage How the curves change with different input voltages Ipoint 2 a Plot the torque speed curve from section 4 3 point b Determine the values of B and T fiction 2points 3 Determine the value of J Ipoint 4 For a torque of upto 0 5Nm plot this motor s steady state torque speed characteristics for Va 42V Label axis with proper units 0 5point 5 The datasheet of this motor mentions a current limit of 6A Will you select this motor to drive a load torque of 1Nm give reason s for your answer 0 5point 49 What is the power loss in the armature of this motor if it is used to drive a load of 0 5 Nm and at 4000rpm If you assume a lossless friction model what is the efficiency of power conversion Ipoint In the above question if a switched mode power converter is used to drive the dc moto
6. Figure 2 8 Control Desk layout for Switchmode DC Converter 29 2 5 Lab Report Include the following results in your report 1 Section 2 3 2 Run the simulation and save the waveform for the switching function Fig 2 3 2 Section 2 3 3 a Duty ratios da and db for the two pole converter b Simulation results of two pole converter model for two different values of V ab one positive and one negative Record the output voltage waveform on the oscilloscope for V41 and Vg w r t COM two probes will be used and obtain by subtraction on the scope the values of Vaipi set in section 2 4 Record the corresponding duty ratio waveforms for the above values Measure the output voltage frequency and comment on the result obtained Hint relate the frequency set in the PWM block to the frequency of the voltage observed on the oscilloscope 24 Experiment 3 Characterization of DC Motor Part 1 3 1 Introduction The output voltage control of a two pole DC Switch mode converter was implemented in real time in the last experiment The purpose of the real time implementation was to obtain a variable DC voltage at the output of the power converter while controlling its amplitude with a dSPACE based Control desk user interface In this experiment a DC motor will be connected to the output of the power converter With this arrangement a variable voltage can be applied to the terminals of the DC motor We will observe that by
7. V The current increases exponentially to the final value The slope of the curve measured at t 0 a e V is dependent on the value of La and R 1s given by m a NOTE Do not exceed V Ai pi 3V in the blocked rotor test Think why 3 4 1 Real Time model A step voltage can be given to the motor using the SHUTDOWN and RESET signal on the drives board The SHUTDOWN signals are controlled by the DIGITAL I O channels 11 and 12 When IO11 12 is 0 OFF state the switching signals are inhibited and the switches are opened Setting IO11 12 to 1 ON state and resetting O10 resumes the regular operation of the converters The IO10 11 I2 digital channels will be added as slave bit out blocks for our model from the slave library In addition two constant locks and two BOOLEAN conversion blocks Search data type conversion in settings change output data type to Boolean should be added with SD1 and SD2 using the same signal The model should like the one shown in Fig 3 4 3l dSPACE RTI1104 SLAVE BIT OUT DS1104SL DSP BIT OUT Cll change the Channel Number to 11 12 similarly Add a RESET button on channel 10 Your model must look like Fig 3 4 Build the model Ctrl B o s Duty cycle a m Oa Duty cycle b Gain2 Gain1 m Duty cycle c Constant dC PWM Stop DS1104SL_DSP_PWM3 E DS1104 ADC C5 motor current la ene Avg Block Enc position Enc delta position DS1104 ENC POS CI Encoder Master Setup D
8. can be written V Ral kgo 6 From equation 6 the armature voltage can be calculated in real time to run the DC motor at a desired speed w rad s Note that there is no feedback here we are calculating the equivalent amount of voltage that need to be applied to run the motor at a desired speed Hence this type of speed control can be termed as open loop voltage control The values of armature resistance Ra and the back EMF constant kg should to be known beforehand The calculated and measured speed is compared at the end of this section 3 5 1 Measurements The connections for this section are the same as in section 3 4 3 Record the values of current and speed for different values of voltages specified in Table 2 NOTE Use the DMM to measure the actual motor voltage between terminals Phase Al and B1 Table 2 Vam V l j o A Speed RPM 3 6 Lab report 0 points 1 In Section 3 3 3 points a Table with values of Motor speed and Measured Eb pt b Plot the values of E vs speed and 1 pt c Calculate the value of kg 0 5 pt d Does the line pass through the origin Should it 0 5 pt 36 2 Section 3 4 3 5 points a Why do we apply a reduced voltage to the motor 0 5 pt b Attach the plot of motor current when a step voltage of 3V is given to the motor 7 pt c Calculate the value of R from this plot 7 pt d Calculate the value of L from
9. Di Filip Li 3 5L4 Li 2 5L R real Z R e R was measured in section 8 2 e Reduce Vasip back to zero Stop the experiment in the edit mode 87 8 6 Lab Report 10 points 1 Induction Motor parameters 6 points Please mention the motor number Value include the units 2 How many poles does the induction motor have 0 5 point 3 Attach the screen shots of dSpace ControlDesk for section 2 2 3 and 4 7 point 4 n the blocked rotor test why do we apply a reduced voltage to the stator windings 0 5 point 5 In the no load test how much power 1s supplied to the motor How much reactive power 1s supplied Is the power associated with core loss Pecore copper loss Peu or both What is the value of Pore 2 point 88 Experiment 9 Torque Speed Characteristics and Speed Control of Three Phase Induction Motor 9 1 Introduction This experiment is divided into three sections 1 Study the torque speed characteristics of a three phase induction motor 2 Induction motor in generation mode super synchronous speed and motoring mode sub synchronous speed 3 Speed control of three phase induction motor by two methods a Using slip compensation without speed feedback 2 b Slip compensation with speed feedback 1 9 2 Torque Speed Characteristics To derive the torque speed characteristics of the induction motor IM it will be operated at a fixed input frequency and a proportion
10. Connections for blocked rotor test and no load characteristics 33 3 4 4 Inductance determination l Open View Control bars Capture Setting Window Change the setting in the capture setting window as shown in Fig 3 7 Drag the reset signal from the model root values into the grey box situated below the level delay set boxes Check the box called ON OFF check the edge direction and the set the level value to 0 5 Also set the length to 0 4 z xl 1 Settings Length 0 4 Auto Repeat Downgampling 1 H Trigger Signal I On Dif Level Delay Model RootfResetyalue Reference Capture Capture Varnables Take Save EA 003 of 003 Figure 3 7 Capture setting window Block the rotors firmly Uncheck and then recheck the SD control This button works as a switch to connect and disconnect the machines from the power supply Set the V motor to a low value not exceeding 3 V and uncheck Reset to give a step input voltage The current should increase exponentially and reach a constant steady state value Now you will observe that every time you uncheck the Reset control in the layout the plot area will display the current and it will stop when it reaches the maximum measurement time The Length is set to 0 4 This will set the data capture time as 0 4s which is large enough to observe the whole transient process in current The screen shots are shown in Fig 3 8 amp 3 9 Check and unch
11. HAKE FROCES5 SUCCEEDED fir Successful completion of Real Time W rkshop build procedure re Finished RTT nuild pru cedure for sided Expl xe a m o Beier cd Wee naeron reser o cmane me est fen E VEM Figure 1 6 Building the Simulink program real time implementation 6 Check the folder Exp1 this should contain the file Expl sdf in addition to the other system files Leave them as such for the proper operation of Control desk Open Control desk by double clicking on the dSPACE Controldesk icon The icon should be located on the desktop of the computer the opened control desk is shown in Fig 1 7 1gnore the lower panel window shown in Fig 1 7 at this moment and also the pop up window showing Expl lay Click File gt Open Variable File A pop up window will appear locate the Exp1 sdf file in the directory Exp1 and click Open Now you should be able to see the lower panel window shown in Fig 1 7 Click File gt Open the pop up window will appear again asking for layout file this time Locate the file Exp1 lay as shown in Fig 1 7 and click Open Click yes if a pop up box opens asking for data connection The layout thus opened should look as shown in Fig 1 8 At this stage the control panel of the control desk is ready to communicate or transfer data with DS1104 via CP1104 Click Start PLAY and switch to the Animation mode The motor will start running It will rotate 1n the positive direction for some time a
12. Increase the value of Wref RPM till 900 and see if the speed is being controlled Save a screen shot of the speed control and attach it in your report e Change the load torque Tref Do not go above 0 1Nm Check if the speed is being controlled e Reduce the speed back to 300 rpm uncheck open closed loop and bring Wref down to zero Stop the experiment in edit mode and close dSpace ControlDesk 9 4 2 With Speed Feedback In this control strategy the actual speed of the motor c is measured and compared with a reference speed The error is speed is fed to a PI controller This controller generates a value for slip slip which is added to the measured speed to generate the frequency reference to the PWM controller The voltage reference 1s proportional V f to this reference frequency PWM Controller Vd UJslip Inverter Figure 9 5 IM speed control PI controller with speed feedback e Open file im speed control pi mdl as shown in Fig 9 6 Build this file Ctrl B Open dSpaceControlDesk and open variable file im speed control pi sdf and then open layout fileim speed control pi lay 95 Speed Measurement V mech RPM IM f sync Hz open closed loop error wslip RPM Reset From 1 PI W_ref RPM f sync HZ 1 Encoder RMS la IM Master Setup DS1104 ENC SETUP Tref Gain Reset PI Curr
13. Lock 79 Uncheck Reset Change the value of W ref and check if motor is tracking the reference speed Change the reference speed to go from 500 RPM to 500 RPM Capture this waveform for the report Forexample see the screenshot of dSpace control desk in figure 7 9 Figure 7 9 Screen Shot of dSpace control desk 7 6 Lab Report 10 points l Section a Attach the waveform of the back emf and index pulse 7 point b Count the number of cycles between two index pulses to determining the number of poles of the motor 7 point c What is the value of theta initial for the rotor to move in the positive direction 7 5 point 80 d What is the value of theta initial for the rotor to move in the negative direction 7 5 point 2 Section 2 a What is the speed of the motor for a current reference isq of 0 5 Attach the waveform 7 point b Change the value of theta inital by 10 does the speed increase or decrease 7 point 3 Section 5 a Give a varying speed reference from 500 RPM to 500 RPM Attach the waveform point 4 List two advantages of PMAC motors 2 points 7 7 References 1 Ned Mohan Electric Drives An Integrative Approach MNPERE 2000 2 Ned Mohan Advanced Electric Drives Analysis Control and Modeling using Simulink MNPERE 2001 81 Experiment 8 Determination of Induction Machine Parameters 8 1 Introduction In this experiment a three p
14. Pim Va x la 4 Pim Tem X Osync 5 Tem Kt Oslip 6 Pim WC 7 ii K To sync Osync Oref T Ogtip 8 e Open file im speed control mdl as shown in Fig 9 4 Build this file Ctrl B Open dSpace ControlDesk and open variable file im_speed_control sdf and then open layout file im speed control lay 93 Vd Slip Compensation Inverter Controller Figure 9 3 IM speed control by slip compensation without speed feedback Varms Duty cycle a RMS_Va_IM Duty cycle b Duty cycle c duty cycle generation IM PWM Stop DS1104SL_DSP_PWM3 wsync_mech_RPM Wref RPM bos ADC DS1104ADC C5 la imotor RMS _ ADC 5 larms wslip RPM Saturation wslip Ic imotor pow compensation wsync mech RPM N 2 pi 80 From 1 wsync_rad sec DS1104ADC_C8 Ib imotor RMS la IM Speed Measurement w mech RPM ENCODER MASTER SETUP DS1104 ENC SETUP PWM Channel 1 m error PWM Channel 2 Tref Gain Vref load Vref PI duty PWM Channel 3 Reset PI Current duty cycle generation DC PWM Channel 4 DS1104SL_DSP_PWM1 ADC DS1104ADC C6 dcmotor Figure 9 4 IM Speed Control Simulink Block Increase Wref RPM while keeping the motor in open loop speed control open closed loop 1s unchecked upto 300 rpm 94 e Check open closed loop Now the motor is speed controlled
15. calculated The steps used in the m file are given below Lans I 42 Voss VAS 0 Atx2nf Z Vrms Z0 Laus Xm imag Z _ Am 2ni The simplification in the expressions above is possible under the assumption that Lm gt gt Lis and therefore Lm Lis Lm and that the branch containing Lir R iS Open Get a screen shot of ControlDesk Now set the frequency reference of induction motor to zero Set the speed of the dc motor to zero so that the machines come to rest Stop the experiment in the edit mode 85 8 4 Rated slip In this section the induction motor is run at rated frequency The DC motor is run under torque control The load torque is increased until the induction motor draws rated load current e Go to Animation mode and check Torque SpeedControl so that the DC motor is torque controlled Slip v fControl Torque SpeedControl e Increase the value in the ref frequency numerical input box to 60 Hz in small steps Now increase the DC motor torque reference while observing the 14 imotor waveform Increase the torque reference so that absolute the speed reduces till the rms current reaches 4 54 A This is the rated current of the machine and it is now operating at rated conditions Take a screen shot of dSpace ControlDesk e nim parameters m enter the speed at which the machines are running 60 0 syn act slip 2
16. iBcSUU I Resetctacesta Perameker Edicnr Window Help a f expt ER Model Root finalTime E Labels currentTime H E Task Info modelStepSize simState errorNumber rti ssertionMode VCLog Viewer A Interpreter A File Select START STOP TEST Jalal e V Log Viewer A Interpreter A File Selector MODE MODE MODE For Help press F1 Astart dea f MATLAB Mgr Simulink Library Pandora Box yINduction Motor WExpi amp controlDesk D Qi BF xe 6 30PM c idocuments and settin Figure 1 9 Various control buttons starting and stopping the system You should be able to observe the speed of the motor on control panel Fig 1 9 The waveform for motor phase current reference speed and actual speed is also shown Press the button Edit mode and then press STOP Take the waveform as shown in Fig 1 10 Study the explanations detailed next The control desk 1s able to access the following data with the help of Exp1 sdf file O O Actual Speed of the motor from W mech subsystem which is inside the Simulink control system You can open the subsystem W_mech you will observe how the input port INCI DSIIO4ENC POS CI of CP 1104 is utilized to read the actual speed of the motor In the actual system this port is connected hardwired to DS1104 though But this port is also a part of Simulink control system hence it will be listed as a variable inside the Exp1 sdf Since the control desk
17. A1 CURR B1 5 6 CURR A2 CURR B2 104 Location in Fig 2 i N CS2 p d Oy mo Phase A1 Phase B1 Phase C1 Phase A2 Phase B2 Phase C2 Figure 3 Power Electronics Drive Board with key lables The location of some key supply and measurement points are shown with labeling in Fig 3 The board provides the motor phase currents currA1 currB1 currA2 currB2 dc bus voltage shown to left of Curr A1 as in Fig 4 to control the motor for a desired speed or torque PE LS F90 bgt R17 E ow Figure 4 a DC Bus CURR Al CURR BI Figure 4 b CURR A2 CURR B2 To generate the controlled PWM voltage source this board requires various digital control signals These control signals dictates the magnitude and phase of the PWM voltage source The DS1104 R amp D Controller board inside the computer generates them 105 1 4 2 Inverters Each 3 phase inverter uses MOSFETs as switching devices The 3 phase outputs of the first inverter are marked Al D 6 in Fig 2 B1 E 6 in Fig 2 CI F 6 in Fig 2 shown with labels at bottom of Fig 3 and those of the second inverter are marked A2 1 6 in Fig 2 B2 K 6 in Fig 2 C2 L 6 in Fig 2 1 4 3 Signal Supply 12 volts signal supply is required for the isolated analog signals output from the drives board This is obtained from a wall mounted isolated power supply which plugs into the DIN connector J90 B 2 in Fig 2 Switch S90 C 2 in Fig
18. CURR AI B 3 in Fig 2 To measure the output current of phase B of inverter 1 e Connect BNC connector to CURR B1 C 3 in Fig 2 To measure the output current of phase A of inverter 2 e Connect BNC connector to CURR A2 H 3 in Fig 2 To measure the output current of phase B of inverter 2 e Connect BNC connector to CURR B2 I 3 in Fig 2 1 4 6 Inverter Drive Circuit The inverters Fig 1 are driven by 3 phase bridge drivers IR2133 The PWM inputs are isolated before being fed to the drivers 1 4 7 PWM Digital Signals PWM and other digital signals for the board are to be given to the 37 pin DSUB connector in Fig 6 and located at H 1 1n Fig 2 For pin out description of this connector see Table 2 1 4 8 Fault Protection Shown in Fig 7 the Drives Board has over current protection for each inverter An over current fault occurring on inverter 1 is indicated by red LED MOTOR FAULT 1 D 2 in Fig 2 while that of inverter 2 is indicated by red LED MOTOR FAULT 2 L 2 in Fig 2 Each time a fault occurs reset the fault using the RESET switch L 1 in Fig 2 on the board The switch resets all the faults 107 Connector PX a s R127 MOTOR a x FAULT Figure 7 a Motor 1 Fault Indicator Figure 7 b Motor 2 Fault and Reset Switch 108 Table 2 37 pin DSUB Connector located at H 1 Ts oon psum e rome BMwemwwsmdotmewri OO Power comerme O Tio eva Ante PWM s
19. Control desk layout file lay were provided Apc s O CP 1104 ee mn From esecsescascase ese ua e 1 ENCODER 7 7 4 INC 1 Input 12 V O Nn Slave I O PWM Control desk E oup TE Im Supply CURR Al 42 V DC Power MATLAB Simulink Power Electronics Drive Board 42 V Al Bl COM Lo OSC DMM GND CH1 CH2 ed DO Lr OO DS1104 R amp D Controller Card Computer Figure 2 1 System Connections In this experiment a Simulink model mdl of a DC switch mode power converter will be built After verifying the simulation results with Simulink model the model will be modified to control the output voltage of the converter in real time A control panel using dSPACE Control desk will be designed lay that will serve as a user interface to regulate the output voltage of the converter In section 2 2 theoretical background to implement DC switch mode power converter in Simulink is briefed Section 2 3 gives step by step instructions to simulate the converter in Simulink In 12 section 2 4 the Simulink model is modified for real time implementation and step by step instructions to design the control panel using Control desk are given 2 2 Theoretical Background of DC Switch mode converter 2 2 1 Switching Power Pole Building B
20. Conversion 2 DS1104 SL DSP BIT OUT C10 2 pi Ts 1000 Gain 5 Speed rad sec e 9 5 Bo E PWM Channel 1 Torque step Switch Torque ref la ref D PWM Channel 2 Tinitial 2 r PWM Channel 3 ADC gt Gain3 PWM Channel 4 DS1104SL_DSP_PWM 1 DS1104 ADC_C6 motor_current 1 constant 1 m un Tem actual Figure 6 3 Simulink model for constant torque on DC motor Torque ref Out1 V motor value Reset value v v Check H 0 96 Length 0 8 V Auto R t Downsamplin 1 4 Tem actual Out1 speed rad sec Out1 SR AAA ae Torque step value Trigger Signal 0 002 109 956 d Check Level 0 5 Delay 0 Model Root Torque step Value Reference Capture Capture Variables Take Save A 002 of 002 o T pa Si E pu speed rad sec Out1 Figure 6 4 dSpace ControlDesk layout for constant torque on DC motor 64 dSPACE I O Board To INC 1 ENCODER 7 A DC Motor DC Motor Load Figure 6 5 Connections for constant torque on DC motor Apply a constant voltage to the dc motor of value 12V Note down the speed of motor when the load torque is zero Give a step change in load torque from 0 to 0 15Nm check the box Torque step and note the resultant speed Theoretically estimate the speed value in rad s What is the net power supplied by the motor What is the quadrant of operation 65 F e OE Wee Tom Doperment beirut Seto Peete Dd CAR Biden Hep
21. Enter the value of the DC supply voltage here gt gt Ts le 4 Build it Ctrl B Make sure the current directory is the same as the location of the mdl file In Matlab main window you will see MAKE PROCESS SUCCEEDED 3 2 3 Connections on the Board as per Fig 3 2 Couple the DC generator and DC motor under test MUT Connect the armature of the DC Motor to the output of two converter poles Al and Bl Connect the CURR A1 phase current measurement port on the drives board to the Channel ADCHS of CP 1104 I O board Also connect the encoder output mounted on the DC motor to the INC1 9 pin DSUB connector on CP 1104 I O board Connect the MUT to a DMM to measure the value of Ep 28 dSPACE I O Board Figure 3 2 Connections for measurement of kg 3 2 4 Creating Control Desk Layout e Open dSPACEControlDesk e Open Variable file sdf select the generated sdf file e File New Layout e Select and draw the following as shown in Fig 3 3 Virtual Instruments Slider Numerical Input Display Data Acquisition PlotterArray e Drag and drop the appropriate values into the Slider Numerical Input etc OR you can download the ke lay file and drop the appropriate values into the instruments 29 V motor Value V motor Value motor current Out1 speed rpm Out1 0 326 Vg V 8778 90 570 8 075 5 578 9 9 0 57 019 9 0 8 0 0 0 8 ICICI CN 3 0 1 08 0 30 20 10 oF 10 20 3 40 zs 0
22. Rs and enter it in the m file im parameters m 8 3 Determine L 8 3 1 Check the phase sequence of the induction motor e Connect the circuit as shown in Fig 8 3 The machines terminals have to be connected as RED A1 YELLOW B1 BLUE CI e Enter Vd 42 Ts le 4 at the Matlab command prompt e Open the file ParameterDetermination mdl and build Ctrl B this file as in Fig 8 2 Varms Duty cycle a RMS Va IM Duty cycle b Duty cycle c PWM Stop c2 DS1104SL DSP PWM3 0 PWM Channel 1 Wref Iref load Speed Measurement error PWM Channel 2 W mech RPM Reset PI speed Vref load Vref PI duty PWM Channel 3 Reset PWM Channel 4 DS1104SL DSP PWM 1 Hz elec o PI Current duty cycle generation DC DS1104ADC C6 dcmotor Idc DS1104ADC C5 la imotor ENCODER MASTER SETUP DS1104 ENC SETUP larms RMS la IM Figure 8 2 Simulation Model ParameterDetermination mdl 83 The simulink model is in Fig 8 2 The experiment can be configured to operate the motors in the modes given below Induction motor a V f control b Independent command for V and f DC Motor a Torque Control b Speed Control e Start dSpace ControlDesk Open the variable file ParameterDetermination sdf and open the layout file ParameterDetermination lay C
23. SETUP PWM Channel 1 d1 PWM Channel 2 load da2 1 Vd 1 Cain 4 db2 PWM Channel 3 Gain3 4 PWM Channel 4 DS1104SL DSP PWM Constant 1 o Ie DE ADC D gt E i I L DS1104 ADC_C6 Load Figure 4 1 Real time Simulink model for motor and load control 4 2 2 Creating the Control Desk Interface Build CTRL B the Simulink mode e Open Control Desk and Open Variable File the sdf file that was generated Create a new layout or download exp4 1 lay and drag the necessary the values as per Fig 4 2 and draw two Slider Gain controls and two Plotters e Drag and drop the V_motor and V_load variables to the Slider gains e Assign one plotter to display motor current and I Load currents and one plotter to display the speed speed rad sec 40 In order to record the numerical values of currents and speed add three Displays to the layout and assign them the speed and current variables The control desk layout should look like as shown in Fig 4 2 Pl Ede Wew took Evpenment Inttreertation Paeform Parametar Cator CAN Wind bab af t PF Stor Bv DAS wes wea 2 REB 42 7 K OBETY 1 230 UN 300 200 100 100 motor current Cutt J Rz a cen speed rad sec utl ce 200 E inn 0 005 0 010 0 015 0 020 mH 000 0 005 0 010 0 015 0 020 Figure 4 2 Control desk layout showing motor current and motor speed 41 4 2 3 Theoretical Background In this experi
24. a 3 I 27 aie d sin 8 sin 6 7 sin 6 7 I 71 K c axis Figure 7 1 Two pole PMAC Machine 7 3 Observing the Back emf of the PMAC Motor In this section the PMAC motor is run as a generator by coupling it to a DC motor as shown in Fig 7 2 e Make connections are as shown in Fig 7 2 dSPACE I O Board Figure 7 2 Connections for Section 7 3 72 Connect Al and B1 phases of the PMAC motor to ADC 8 for measuring E and make sure that the third terminal of the PMAC is NOT connected anywhere NOTE For some motors Al B1 correspond to Red and Yellow and in some cases we need to check the phase sequence of the motor The phase sequence of the motor can be checked by applying a small voltage 7 1 V between phases in order AB BC and CA if the speed if positive counter clock wise this is the correct sequence ABC If the speed is negative clockwise then interchange any two phases Download and extract the Lab 7 files to the desktop Start Matlab and set the working directory to this folder Open PMAC pole Det index mdl Set Vd 42 Ts le 4 in the Matlab prompt Build this model Ctrl B Open dSpace ControlDesk and open the PMAC pole Det index sdf file and the corresponding pmacpole indexdet lay file In capture setting window set the length to 2s Apply a voltage to the DC motor such that the speed 1s positive Observe the Speed encoder position and back emf of the PMAC Motor NOT
25. and PHASE B2 terminals on the power board Set the supply voltage Va to be close to 42V e Ensure a firm mechanical coupling between the motors Add necessary blocks to make the model shown in Fig 4 1 All the required blocks can be copied from the file tomponents mdl Or you can build it by following the instructions a to f below 38 a Add a second set of voltage control blocks in the Simulink model and connect the duty cycles to the 2 and 3 inputs of DS1104SL_DSP_PWM b Setthe switching frequency as 10000 Hz in the PWM block c Double click the DSII04SL_DSP_PWM block go to PWM Stop and Termination uncheck Set all Ch and then click on Set all d Connect the CURR A2 channel to ADCH on the controller box e Make the load current CURR A2 available in the Simulink model by copying the first current measurement blocks and then double clicking on DS1104ADC C5 and changing it to channel 6 f Save the model The model should like the one shown in Fig 4 1 e In Matlab enter Vd 42 Enter the Vd supply voltage here and Ts 1e 4 39 Ka Duty cycle a V motor 1 Vd CD gt dAdB NB Duty cycle b Gain2 Gain1 px Duty cycle c Constant dC PWM Stop DS1104SL DSP PWM3 ADC al PWM Control DS1104 ADC_C5 motor_current la Avg Block Enc position Enc delta position DS1104 ENC POS CI 2 pi Ts 1000 wm rad sec Gain 5 speed rad sec Encoder Master Setup m DS1104 ENC
26. can be calculated using the index pulse of the encoder Depending on the installation of the encoder the index pulse may not be aligned with B Let the zero crossing of E be 74 considered to be the reference 0 as shown in Fig 7 4 The index pulse is observed only at Qindex Hence when calculating the value of Oaa an initial offset Oinitia must be added For a positive direction of rotation the value of Ojnitia is given by 044 in Fig 7 4 the angle between the positive peak of B and the index pulse and for a negative direction of rotation it is given by Oaa the angle between the negative peak of B and the index pulse The values of 044 and Oga can be calculated using 4 and 5 respectively NOTE E lags E by 30 and B lags E by 90 ai Ops Oindex O ps 1 7 6 4 Oaa 05 index 85 n1 6 5 Bmax pi Api 3 opi 3 2pi 0 0 pi 3 2pi 3 Figure 7 4 Determination of Qjnitia when PMAC has positive speed 7 4 Current Controlled PMAC Machine 7 4 1 Theory The equivalent circuit of the PMAC motor after dq transformation 1s shown in Fig 7 5 a The parameters of the motor are listed in Table 1 The current and speed controllers can be designed using the steps in experiment 5 Or use the controller values given in Table 2 The simulink model for current control of PMAC motor is Fig 7 7 The angle theta da is calculated using the enc position and theta initial If theta initial is set to the
27. changing the magnitude of the applied voltage the speed of the motor can be varied This is also referred as open loop voltage controlled DC motor The electrical parameters of the motor can be calculated by the open circuit and blocked rotor tests and the voltage vs speed characteristics can be verified The objectives of this experiment are 1 To observe open loop speed control of a DC motor 2 To calculate the motor back emf constant kg 3 To calculate the electrical parameters Ra and La of the motor using the blocked rotor test 4 Verify the voltage vs speed characteristics of the DC motor 3 2 Control of a DC Motor in Open Loop Varying its supply voltage can change the speed of a DC motor The model of output voltage control of the switch mode dc converter was discussed in Experiment 2 and the same will be used e Use the model for the two pole switch mode converter Fig 3 1 OR download the file two _pole mdl from online e Change the name of the Constant block from V_ab to V_motor this will be the input voltage of the DC motor 25 3 2 1 Adding current measurement blocks For measuring the current Channel 5 of the A D converter ADCHS5 on CP 1104 will be used Remember that the data have to be scaled by a factor of 10 In addition the current sensor outputs 1V for 2 amps of current therefore it actually needs to be scaled by 20 shown in Fig 3 1 e Drag and drop the DSIIO4ADC C5 block from the dSPACE libra
28. lx dt y dt d By knowing p 1 0 and graphically determining the slope 3 of the speed curve at t 0 t 0 the system inertia J can be calculated using equation 8 45 4 4 1 Simulink model for dynamic parameter determination Include the SHUTDOWN and RESET signals as done in Experiment 3 Your model should look like Fig 4 4 V motor m E dAdB 1Vd gt Gain2 Gain E Duty cycle c Constant dC PWM Stop P DS1104SL DSP PWM3 ADC MC W ontrol DS1104 ADC_C5 motor current la Duty cycle b Avg Block Enc position Enc delta position DS1104 ENC POS CI 2 pi Ts 1000 wm_rad_sec Gain 5 speed rad sec Encoder Master Setup E DS1104 ENC SETUP PWM Channel 1 d1 PWM Channel 2 V load Vds amp E be Gain 4 db2 PWM Channel 3 SN PWM Channel 4 Constant 1 EZ DS11048L DSP PWM d4 DS1104 ADC C6 Load U 7 boolean Data type Conversion 1 DS1104 SL_DSP_BIT_OUT_C12 4 an ee SLAVE BIT OUT Reset Data type Conversion 2 DS1104 SL DSP BIT OUT C10 Figure 4 4 Simulink model to determine J 46 4 4 2 Control desk layout for dynamic parameter determination Make connections as in Fig 4 6 for determination of J e Start dSPACE ControlDesk and open the generated sdf file from File Open variable file e Open the Layout file and include two CheckButtons assign them to Reset and SD Fig 4 5 F e Ede Vew Toot Expermert Instrumentso
29. reference speed command to the DC motor from positive speed 200 rad sec to negative speed 200 rad sec with a constant ramp The speed controller designed in the previous experiment is used to track the instantaneous reference speed command Fig 6 1 shows the Simulink model file of the system and Fig 6 2 shows the hardware connections To keep the same inertia the same as the ones used to design the speed control loop in the Experiment 5 another DC motor is coupled to the DC motor whose four quadrant operation is desired The terminal voltage Va current Ia and speed amp torque relations are given below _ Va C Es a HE kyI kr k g 2 T em Real time implementation Modify the file obtained from Experiment 5 which was used for speed control of the dc motor to give a stepped waveform that goes from 200 rad sec to 200 rad sec Fig 6 1 Save the waveform for the reference speed and measured speed and label the quadrant of operation 61 SLAVE BIT OUT DS1104 SL DSP BIT OUT C10 boolean Data type Conversion 2 Duty cycle a PI Speed reset DS1104 ADC C5 PI Current reset Gain2 constant motor current Avg Block Enc position Enc delta position p 2 pi Ts 1000 DS1104 ENC POS CI Gain 5 motor speed Encoder Master Setup DS1104 ENC SETUP Repeating table tmask link Duty cycle b Duty cycl
30. speed from 100 rad sec to 300 rad sec e Build CTRL B the model and start dSpace Control Desk e Open the variable file sdf and then open the layout file dc motor speed control lay and add values as shown in Fig 5 9 e Run the experiment and compare the real time results with the simulations b EIDE Pegh os Auto Repeat Downsampling 1 Reset value Trigger Signal Level D Delay 0 k lt Drop trigger variable here gt gt Reference Capture Capture Variables Take Save W003 of 003 V Check 5 o t 2 5 o 5 3 E eoe e e i a e I 0 27 4 B OS 40 12 44 1B 18 20 22 24 26 2 A 6 8 10 12 14 16 AG 20 22 24 326 Figure 5 9 Control desk interface for DC motor control for step from 150 rad sec to 350 rad sec 5 5 Lab Report 0points l Section 5 2 Run the simulation with default configuration parameters for 10 sec for the following two cases Check the observed values with calculated values show your calculations Save the plots and include them in your report 2points 59 a Va 20V Load Torque 0 3 Nm b Va 20V Load Torque 0 Nm 2 Section 5 3 a b d Report your calculations for current and speed controller Note Design current controller for a bandwidth of 100 Hz phase margin 90 deg and speed controller for a bandwidth of 10Hz Phase margin 60 deg For designing the speed controller you can assume B 0 but while building the Simulink bl
31. voltage of the two pole converter is the difference between the individual pole voltages of the two switching power poles The average output voltage Vo Vab can range from V4 to Vq depending on the individual average pole voltages Vo m Vab VaN VbN 4 To achieve both positive and negative values of Vo common mode voltage equal in magnitude to V4 21s injected in the individual pole voltages The pole voltages are then given by Va Vo VaN 5 aN 7 7 5 mess cM OM Von 2 6 Nim e 6 solving equation 1 to 6 lv da Ventrla 7 P um 7 d lv dp Ventib po 8 d The above equations will be implemented in Simulink 2 3 Simulation of DC Switch mode Converter 2 3 1 Triangular waveform As explained in section 2 2 2 to modulate the pulse width of the switching signal in a power converter a control voltage has to be compared with a triangular waveform signal This triangular waveform will be generated in Simulink using the Repeating Sequence block 14 Create a new directory for the experiment say Expt02 start Matlab and set the path to this directory Type simulink at the command prompt and create a new model from File New model Access the Simulink library by clicking View gt Library Browser In the Library Browser expand the Simulink tree and click on Sources Drag and drop the Repeating Sequence block into your model simulink blocks usually have properties t
32. waveform for a step change in speed c Speed waveform for a step change in speed Figure 5 5 Simulink model and result for cascade control 5 4 Real time implementation of feedback control For dSPACE implementation the dc motor model will be replaced with the real motor and power converter with 42V dc supply will replace Kpwm block The control voltage to duty cycle conversion was already discussed and implemented in experiment 2 All the necessary components to make the model in Fig 5 7 are provided in the file components mdl If you would like to build it the instructions as in a to f are given below 56 a Add the reset block used in the previous experiment b Modify the Speed Control block as shown in Fig 5 6 Change the integrator block parameters by double clicking on it and changing its external reset to either Open the Current Controller and change its integrator s reset as was done in the Speed Control Connect the reset inputs of speed controller and current controller as shown in Fig 5 6 These changes allow the integrators to start up correctly in the real time environment Saturation Integration Figure 5 6 Speed Controller SLAVE BIT OUT DS1104 SL DSP BIT OUT C10 boolean Data type Conversion 2 Wref 4quad Duty cycle a PI Speed reset Duty cycle b PI Current reset 1 Duty cycle c constant dc PWM Stop ADC DS1104SL_DSP_PWM3
33. waveforms corresponding to sub synchronous super synchronous and synchronous speeds 7 point b What is the power supplied to the induction motor in all three modes 7 point c Comment on why there power at 10 slip 1s not equal in magnitude to that at 10 slip 1 point Section 3 a Attach the screen shots of the speed controlled IM from section 3 1 and 3 2 7 point b Give one advantage of each speed controller in section 3 1 and 3 2 7 point 9 6 References 1 B K Bose Modern Power Electronics and AC Drives Pearson Education Prentice Hall 2 Ned Mohan Electric Drives An Integrative Approach MNPERE 2000 97 Appendix A safety Precautions and Power Electronics Drives Board CP1104 I O Board DS 1104 Control Board and Motor Coupling Unit familiarization 1 1 Why is safety important Attention and adherence to safety considerations 1s even more important in a power electronics laboratory than it s required in any other undergraduate electrical engineering laboratories Power electronic circuits can involve voltages of several hundred volts and currents of several tens of amperes By comparison the voltages in all other teaching laboratories rarely exceed 20V and the currents hardly ever exceed a few hundred milliamps In order to minimize the potential hazards we will use dc power supplies that never exceed voltages above 40 50V and will have maximum current ratings of 20A or less We use a
34. 2 controls the signal power to the board The green LED D70 C 2 in Fig 2 indicates if the signal supply is available to the board Fuses F90 C 2 in Fig 2 and F95 B 2 in Fig 2 provide protection for the 12 V and 12 V supplies respectively Please note that the green LED indicates the presence of only the 12 V supply Please note that turning off S90 will not stop the PWM signals from being gated to the inverters The power supply for the 3 phase bridge drivers for the inverters 1s derived from the DC Bus through a flyback converter A 2 in Fig 2 1 4 4 Voltage Measurement Test points are provided to observe the inverter output voltages BNC connector VOLT DC Fig 5 and located at B 4 1n Fig 2 has been provided to sense the DC bus voltage To measure the DC bus voltage e Connect a BNC cable to VOLT DC BNC connector e The scaling factor of input voltage is 1 10 1 4 5 Current Measurement LEM sensors are used to measure the output current of the inverters Only A and B phase currents CURR Al and CURR Bl are sensed The C phase current can then be calculated using the current relationship I I I 0 assuming that there is no neutral connection for the machines The calibration of the current sensor is such that for 1A current flowing through the current sensor output is 0 5 V The current measurement points are shown in Fig 4 106 To measure the output current of phase A of inverter 1 e Connect BNC connector to
35. B Simulink and Control desk In this experiment you will be briefly introduced to the role of above mentioned four components in the DSP based electric drives system An example of speed control of a DC motor will be demonstrated The Simulink file and Control desk layout will be supplied to perform this experiment The communication between the four components will be explained while controlling the speed of the motor Section 1 2 details the DSP based electric drives system vis vis the role of the four components listed above In Section 1 3 a step by step procedure to run the DC motor speed control will be performed 1 2 DSP based electric drives system Fig 1 1 shows the block diagram of the DSP based electric drives system e Motor coupling system This system contains the motor that needs to be characterized or controlled The system has a mechanical coupling arrangement to couple two electric machines The motor under test MUT or whose speed torque needs to be controlled could be either a DC motor or a Three phase induction motor or a Three phase Permanent Magnet AC PMAC motor The system also has an encoder mounted on the machine which is used to measure the speed of the MUT This can be used for close loop feedback speed control of the motor The motor demands a controlled pulse width modulated PWM voltage to run at controlled speed or torque The PWM voltage is generated by Power Electronics Drive Board briefed next the voltage s
36. DC PWM Channel 4 DS1104SL_DSP_PWM1 reset b B D3 DS1104ADC_C6 dcmotor Idc 0 08 tdcl s i ES TDC DS1104ADC C5 la imotor la t ENCODER MASTER SETUP gt In RMS larms DS1104 ENC_SETUP RMS la IM Figure 9 1 Torque Speed Simulink File e Start Control Desk and open the variable file Torque Speed sdf and then the layout Torque Speed lay e Go to Animation mode and check Torque SpeedControl so that the DC motor is torque controlled Torque SpeedControl 90 e Make connections as shown in Fig 9 2 Make sure the phase sequence of the induction motor IS correct dSPACE I O Board JT ENCODER 3 phase Induction Motor DC Motor Load Figure 9 2 Connections for torque speed characteristics speed control of three phase induction motor e Increase the value in the Fref Hz numerical input box to 30 Hz in small steps Change the torque of the dc motor in the direction to increase the slip decrease the speed of the motor Ignore the sign of torque and measure the speed of the motor Fill out the Table 1 as you increase the load torque Do the same at 45 Hz and 60 Hz Note Always bring Tref back to zero and then change Fref Hz slowly Make sure the RMS value of IM current does not exceed 4 5A Think why do we increase the applied frequency slowly If the motor is at 0 speed and 60Hz voltages are applied to the IM what will happen e
37. DSP Based Electric Drives Laboratory USER MANUAL Department of Electrical and Computer Engineering University of Minnesota Revised August Ist 2012 CONTENT EXPERIMENT 1 INTRODUCTION TO THE DSP BASED ELECTRIC DRIVES SYSDE V A iR Mua mS UU MUS Fa E M EC IRURE MeEEE NOME 1 Ig INTRODUCTION cerr tae eee ee ee 1 2 DSP BASED ELECTRIC DRIVES SYSTEM ee ee 1 3 DEMONSTRATION OF SPEED CONTROL OF A DC MOTOR ccc ce ccce eee eeeteenseeeeeeeesceeaee eae 4 L4LAB REPORT AND READING ASSIONMIEN U iir cca Dat E Waa Gaston de Wena uted eae 11 EXPERIMENT 2 SIMULATION AND REAL TIME IMPLEMENTATION OF A SWITCH MODE DC CONVERTER irosit tr LU ani S XE RRECE UUEUSN UE EbUD EN IP UEM MEE 12 2 LINTRODUCLION ut ee Cateye been aul LE LM xL M EL I E UID Mu E LE C Le 12 2 2 THEORETICAL BACKGROUND OF DC SWITCH MODE CONVERTER enm 13 2 3 SIMULATION OF DC SWITCH MODE CONVERTER 1 78S TREE ee EREETEDU E bpr REA Ne eO SES 14 2 4 REAL TIME IMPLEMENTATION OF DC SWITCH MODE CONVERTER eem 19 2A CAB REPOR ic er THEE 24 EXPERIMENT 3 CHARACTERIZATION OF DC MOTOR PART 1 25 Oe LAIN TER OPO UC TON sii sect EE 25 32 CONTROL OF A DC MOTOR IN OPEN LOOP rences pn voice UH UR nud bu E AAE E 25 3 3 DETERMINATION OF KAOPEN CIRCUIT TEST hire E aE ea 30 3 4 DETERMINATION OF ELECTRIC PARAMETERS BLOCKED ROTOR TEST esse 31 3 5 OPEN LOOP SPEED CONTROL VOLTAGE VS SPEED CHARACTERIS
38. E The ADC can measure a maximum of 10V the back emf must not exceed this hence do not run the motor faster than 50 rad sec 5V save the waveform from ControlDesk as motor emf mat and use the code in PMAC m to calculate the value of theta initial and back emf constant Ke For example see the screen shot in Fig 7 3 where the length has been set to 1 5 in the capture setting window 73 Speed Meas remeti mech aceco nong 5 o E D E a Im MI pm pre uin mm DO epum r 2 gee _ Miri D21104ENMC AVY INDEX C1 Index 10 01 02 sr 05 dts 07 0 09 10 114 12 13 14 Figure 7 3 Screen Shot of ControlDesk 7 3 1 Observation of the index pulse The encoder generates 1000 pulses per rotation each time the motor completes one rotation an index pulse is generated that resets the encoder position value back to zero 7 3 2 Observation of the back emf For one complete mechanical rotation of the motor the number of electrical cycles completed is given by p 2 where p is the number of poles of the motor In this lab motors have 8 poles Count the number of cycles between two index pulses to determine the number of poles of the motor 7 3 3 Determine the value of Oinitial The equations to determine the value of initia are given in PMAC m file from lines 29 to 39 The explanation 1s given below In order to control the PMAC motor it is essential to know the exact position of the rotor This position
39. Electronics Drives Board In this experiment the output voltage reference will be set from the Control desk interface The duty ratios for the two poles will be calculated from this output voltage reference inside DS1104 PWM will be internally performed and the switching signals thus generated will be sent to the power electronics drives board through the CP1104 I O interface Make connections as shown in Fig 2 1 dSPACE provides a block called DS1104SL DSP PWMS3S which embeds the triangular waveform generator and the comparator for all converter poles The inputs for DS1104S8L DSP PWM3 are the duty ratios for the poles In Fig 2 5 the lower part of the model is called the Duty Ratio Calculator This part of the model will again be used in the real time model to generate the pole duty ratios The triangular wave generator and comparison using relays will be replaced by DS1104SL_DSP_PWM43 as these functions are internal to the block Two legs of the drives board refer appendix A will replace the two poles modeled using the Switches in Simulink e Create the real time model as shown in Fig 2 6 Use the Duty Ratio Calculator from section 2 5 9 e For the DS1104SL_DSP_PWM5S block set the switching frequency as 10000 Hz and the dead band to 0 DS1104SL DSP PWM3 from dSPACE RTII1104 Slave DSP e Make the following changes in the Configuration Parameters o Simulation Configuration Parameters Change the stop time to inf
40. Open the file im torquespeed m and enter the value of speeds in lines 10 11 and 12 corresponding to frequencies 30 45 and 60 Hz Enter the load torque of the dc motor in line 13 The electromagnetic torque applied by the machine is found in lines 14 through 16 of the script Run this section of the script till line 24 The values of Tem V s per slip speed RPM are plotted Calculate the value of Kro using equation 2 9 Ton K T5 O slip 2 O Lines 28 33 plot the plot Tem V s per unit speed S 0 sync e Lines 34 40 plot the plot Tem V s speed in RPM a Table 1 0000 0000 0 040 fF 0000 So 0080 fF oio 0 01200 J 0 S 0150 9 3 Generating and Motoring Mode of Induction Motor In this section the generating and motoring modes of the Induction Motor can be studied by coupling the Induction motor to a DC motor The DC motor is run under speed control e Goto Animation mode and set it up so that the DC motor is speed controlled Torque speed characteristics Torque SpeedControl e Increase the DC motor speed Wref to 900 RPM Set the induction motor frequency Fref Hz to be 30 Hz This case is for zero slip Set the length of capture to be 0 2s Observe the induction motor phase a current and voltage Save the waveform as atsync mat e Keep the induction motor frequency set at 30 Hz Vary the speed of Wref
41. R MASTER SETUP i DS1104 ENC_SETUP G P gt m Duty cycle a c3 0 5 Switch Duty cycle b m i D l 0 5 d lim L Duty cycle c DC CMvoltage i DS1104SL DSP PWM3 i AN abc gt dq la gt a X Product la hb X is dq Ib ale Ib theta da Rese From 1 0 0 E isd V eed vsd From 3 Isd ref Vsdq ref o Speed reset a vsq V_abc To start the system Isdq ref Subsystem1 1 Uncheck Lock reset 2 Uncheck Reset Subsystem2 7 ihota da 4 set the reference From 2 dq gt abc 5 note that fs 50 KHz feso From 2 Resetlnteg 1 Reset const Go to 1 w ref Figure 7 8 Simulation Model The model is shown in Fig 7 6 In this model the speed of PMAC can be controlled The error between the measured speed and actual speed is passed through a controller This controller generates a reference value for isg The PI controller for speed is designed with a cut off frequency of 10Hz which is much slower than the current control loop 3 Build Ctrl B the mdl file 4 Open dSpace ContrlDesk and open the variable file PMAC current sdf Open the file PMAC current lay 5 Uncheck
42. RECTORY Ci Ci lDocuments and Zsttingaiz 270A DesktopiExpl i ume sie metu 2 BUILD DIRECTORY C Documents and Settingsiz 270iDemktopikxpi Ex ENC SETUP TARGET COMPILER CiiPFRCTonlacDe Cues ad begt Deap C 1 HT ixi B dsuble oS E ixi s aune at COMPILING Ewpl c id im TEER e NET COMPILING Fxpl dara c COMPILING C Xd5PACEVHATLAPAETILIO4ACirCi sim engine c SUSY COMPILING CitdSPACEVEATLABAETILIDAXCAEti init c c 7 COMPILING Cixd5FACKNRATLABXETILIO O4d CNgL external sim c occum P and 2e kir oe e Voc enis 7 z amp J n COMPILING Ci RATLASE SV cee clare oie e winet aqua saa men MEFums rate type o cz mariansps cew c are ee_sin c COMPILING CIiXd5PACEVHATLABAETIIIO4dACYiET assert e Eep rci1104 Foist COMPILING C idSPACEVHATLABARTILIDAVCAETA slvllO4 c mech FP CI erpi tay LAY File CL ext map HAF File USING LIURART CivdSPACEVMATLAUAETILIO4ACALibirtwlib riJ 0 dell plna Bode l ISL DSP PWM LINKING APPLICATION me C Espi ppe FFE File LINKING FIWTSHED Ci expi sar 3DF File E DL Expl tre TRE File LOADING APFLICATIUN Expl sdf Lex 3 danh ems dE 81 dil RTT Inirialiring 720 ck puer sz dsilO4 RTLID a5PACE alave DSP fir amp ware rev 2 5 detec C Enpi usr ni Hs File 2 daii RTE Initialization completed TEL fi dall 4 PTI similation state RI TUO LOADING FINTZSED
43. S1104 ENC SETUP SD Data type Conversion 1 wm RPM Speed rpm SLAVE BIT OUT DS1104 SL DSP BIT OUT C11 SLAVE BIT OUT DS1104 SL DSP BIT OUT C12 1 boolean SLAVE BIT OUT Reset Data type Conversion 2 DS1104 SL DSP BIT OUT C10 Figure 3 4 Simulink model for blocked rotor test 3 4 2 Creating Control Desk Layout Reload the variable file and modify the layout to include a CheckButton for SD and Reset Virtual Instruments CheckButton as in Fig 3 5 or open the exp3sdreset lay file 32 kE de de Ven Task xpennent minenn Pathos Paeete Ditor CAM Windoe Hal wie Hn Ceo Be ee HR mU a OO Ah Me E ooo 0 000 KR 0 g E Me Farias LE BP Aun Beet Trga Signal D Tipiy Level D Deas D E Fra v Drop tiges variable here oo li Gime A Capiu Variables aonne Capture Dum LU Take Sih i meu e a asas fA Mae th ui E TITIITI ag Muki eE E io A Harare T Dain ET Purhilution E zl Rahon E S alaskan Fine S Seniors ibm zl EIE fy Siema eris Di ed ed So ar a a d Wa Bt 3 09 4 Of 68 OF Of OF 1n i a8 CSP PETE Leg Wiesner Ay ikepretior A Ha Seiser j Merum amd sring hhh LP me Fev Hsin press FL EDIT HUM Sn SE Figure 3 5 Layout for blocked rotor test 3 4 3 Connections on the Board Make connections for blocked rotor test as in Fig 3 6 dSPACE I O Board From Encoder 3E ENCODER Figure 3 6
44. TICS 0 0 cece cee ee eee e 36 DO LAB RE ROR Maasai p I 36 EXPERIMENT 4 CHARACTERIZATION OF DC MOTOR PART 2 38 dL INTRODU UCTION 2 iiie ttd Ea Suite ooa to bd oe eA a nee a a ole 38 4 2 O0PEN LOOPCONTROL OF DC MOTOR WITH LOAD iie sez etes hu EE teh xo er agb Uer E ERE AREE coe 38 4 3 OPEN LOOP CONTROL OF DC MOTOR WITH LOAD TO CALCULATE B AND Tgcriox 44 44 DEPBRMINATION OPFTINERTDX 2 d acies det sdtss titre uten RO edet aevi adaus oet ecte e gmetotas ole Rund 44 EXPERIMENT 5 DC MOTOR SPEED CONTROL ceeeeeeee eene 51 gt INTRODUCTION ccc A TA E A AS 5 52 SINUPEINK NIODELE OE THE DC NIOTOR i iiiiedrecta suain bu D oto dan Pap io pU sa dant eet tede oet nere Mende 5 5 CONTROLEER DESIGN a5 rotsda sac etos edo eter iHi eea donut VaetbeDetuv tees ame eua ub elitkap battu coit ci UE 53 3 4 REAL TIME IMPLEMENTATION OF FEEDBACK CONTROL eese eene ehh hene nnn n 56 2 95 UAB REPORT S eoeno iios ietexicisitntiaie a a sage saiune cau oaiancainte aston a aN 125509 JOUR PEIN ES orenen a utis oes dum Mi Sut atf docebit unte aia sa cec pM uique 60 EXPERIMENT 6 FOUR QUADRANT OPERATION OF DC MOTOR 01 CFINTRODUC HON Rc rRETT 61 6 2 FOUR QUADRANT OPERATION OFA DO MOTOR ieixestio card e vob ave ceaveiarscacskvbinbendapiesaawerdes 61 6 3 DE MOTOR UNDER TORQUE CONTR Oleg arera a E A rush hata vee RUIT 63 Og CLOSED LOOP SPEED CONTR OU wess
45. al input voltage defined by the V f ratio The DC motor will act as a variable load and the value of the load torque will be varied by Tref In addition to the DC motor torque the induction motor will also experience a coulomb friction torque and viscous friction torque Note The speed is measured from the DC motor hence the speed of the induction motor is the negative of the measured speed Im Toc Isiction Bo 1 T iction 0 1Nm B 0 0002 Nmsec rad from Lab 4 e Download the files Exp 9 and extract its contents to a folder on the desktop Start Matlab and set the work directory to this folder 89 set Vd 42 Ts le 4 at the Matlab Command prompt Open the Simulink file Torque Speed mdl and build it Ctrl B as shown in Fig 9 1 Here the induction motor is V f controlled The induction motor is coupled to a DC motor and this DC motor is run under zov E var Torque control or Speed Control Vd In RMS E Varms Duty cycle a ENTIS V Va m m Duty cycle b LE duty a b c aa Duty cycle c duty cycle generation IM PWM Stop DS1104SL DSP PNM3 c2 0 1 0 08 gt E PWM Channel 1 error Wref Iref load d2 Speed Measurement Reset error PWM Channel 2 PI Speed Vref load Vref PI duty W mech RPM PWM Channel 3 Reset PI Current duty cycle generation
46. aline Po foma emen Digital ground T E Tir rran eeeasma OO lm pM e ve SSS afe moms 00 Lo onn mme s xe meceees 00 wc mecmems ww eme 0 T s ape puces 109 1 5 DS1104 R amp D controller Board and CP 1104 I O board In each discrete time step the DS1104 R amp D controller board fitted as an add on card in computer takes some action to generate the digital control signals The type of action is governed by what we have programmed in this board with the help of MATLAB Simulink real time interface This board monitors the input 1 e motor current speed voltage etc with the help of CP1104 I O board in each discrete time step Based on the inputs and the variables that need to be controlled 1 e motor speed or torque it takes the programmed action to generate the controlled digital signals The CP1104 I O board Fig 8 is an input output interface board between the Power Electronics Drive Board and DS1104 controller board It takes the analog signal motor current dc voltage etc from the Power Electronics Drive Board in its ADC ports and also speed signal from encoder at its INC ports from motor coupling system to the DS1104 controller board In turn the controlled digital signals supplied by DS1104 controller board are taken to the Power Electronics Drive Board by CP1104 It also has 8 ADC ports to accept analog signals 8 DAC ports to output analog signals and other digital I O connector
47. and the second input port is the control port Main Signal Attributes Stitch Criteria for passing First input u2 gt Threshold ne Threshold I5 jo F W Enable zero crossing detection S ample time 1 for inherited 1 Figure 2 4 Settings for switch block 18 e Set the simulation parameters and values of fsw and Vd as in section 2 3 2 Run the simulation e Collect the following results o Switching function q 7 for pole A of the two pole converter o Simulation results of a two pole converter model for two different values of V ab one positive and one negative Two pole Converter Mode ioi Wd Wd WV aM E r a a C Pole A Scope WM ab Repeating i O a Sequence WV bH Ventil a Relay Pole B V entrl b S cope1 Duty Ratio Calculator da db SS CSS ABE SER SS 92 2 ABB Gas Figure 2 5 Two Pole Switch Mode Converter Model in Simulink 2 4 Real time Implementation of DC Switch mode Converter Having simulated the two pole DC switch mode converter it will now be implemented in real time on DS1104 This means that the converter will now be implemented in hardware and its output voltage amplitude will be controlled in real time using an interface made possible by the use of dSPACE Control desk As explained in experiment 1 real time implementation involves exchange of signals between the dSPACE Control desk interface DS1104 and the Power 19
48. ce Figure 5 4 Simulink model and result for current control loop The Simulink model for the cascade control and the waveforms for speed and current are shown in Fig 5 5 a Please make sure that wm from DC motor is fed back to wm in PI speed block and Ia from DC motor is fed back to Ia in PI current block The Speed PI controller has a current limit output of 5A necessary to limit the current during transients both in simulation and real time systems To check the controller design we will give a step change in the speed reference This is implemented using a constant and step source blocks Fig 5 5 a The results of cascade control are shown in Fig 5 5 b and Fig 5 5 c If the controller parameters were correctly tuned then it s time to go on for the next step and implement the controllers in a real time system Set the simulation output of speed response for a step input varying from 100 to 300 rad s run the simulation for 2 sec fixed step odel and time step 1e 4 55 Set the speed reference to be 200 rad sec and give a step change in the load torque from 0Nm to 0 3 Nm at 1 sec run for 2 sec Attach the graph in your lab report M motor DC Matar a Simulink model for cascade control Following are examples of waveform in Fig 5 5 where a step change of 100 to 350 rad sec are shown la la_ref E Bl Ed amp E3 092 dta 9 a a amp 30 dates ik Time offset Time offset 0 b Current
49. d to the layout These parts are available in the window to the right of the layout The output voltage reference V AB will be set using a Slider and a Numerical Input Both these parts are found under Virtual Instruments Click and draw these parts in the layout The duty ratios will be observed in a Plotter available in Data Acquisition Select Plotter and draw it in the layout 27 e Now appropriate variables will be assigned to the parts Under Model Root locate V AB and select it It will have a parameter called Value right side panel which corresponds to the value of the Constant block V AB in the real time Simulink model Drag and drop V AB Value into the Slider and also on Numerical Input one by one Now the value of V AB can be changed in real time using these two parts Similarly to observe the duty ratios in real time assign the two outputs Out1 and Out2 of the De mux the one following the Gain2 block to the plotter The experiment is now ready it should look as shown in Fig 2 8 Start the experiment by clicking the Start button and select the animation mode Fig 2 8 e Turn the power supply ON and observe the pole voltages on the oscilloscope Vary the output voltage reference V AB using the Slider or the Numerical Input Observe the changing duty ratios and pulse widths of the pole voltages M Fe Ede ew Tous Fxperment instrumentation Patom Foamete Edir CAN Window Hep 9 i ta Poi Bw BS ee ma TES gU 20K OF ae aes
50. dc supply of 42V However in spite of this precaution power electronics circuits on which the student will work may involve substantially larger voltages up to hundreds of volts due to the presence of large inductances in the circuits and the rapid switching on and off of amperes of current in the inductances For example in Power Electronics laboratory a boost converter can have an output voltage that can theoretically go to infinite values if it 1s operating without load Moreover the currents in portions of some converter circuits may be many times larger than the currents supplied by the dc supplies powering the converter circuits A simple buck converter 1s an example of a power electronics circuit in which the output current may be much larger than the dc supply current 1 2 Potential problems presented by Power Electronic circuits e Electrical shock may take a life 98 e Exploding components especially electrolytic capacitors and arcing circuits can cause blindness and severe burns e Burning components and arcing can lead to fire 1 3 Safety precautions to minimize these hazards 1 3 1 General Precautions e Be calm and relaxed while working in Lab e When working with voltages over 40V or with currents over 10A there must be at least two people in the lab at all times e Keep the work area neat and clean e No paper lying on table or nearby circuits e Always wear safety glasses when working with the circuit a
51. e c PWM Stop DS1104SL_DSP_PWM3 PWM Control Output a repeating sequence of numbers specified in a table of time value pairs values of time should be monotonically increasing Reset Parameters F Time values 0151625 26 Wret_4quad Output values 200 200 200 200 2001 Figure 6 1 Simulink model for four quadrant operation of DC motor 62 dSPACE I O Board To INC 1 5 ENCODER 7 A DC Motor DC Motor Load Figure 6 2 Connections for four quadrant operation of DC motor 6 3 DC motor under torque control Part a Modeling of a constant load The Simulink model for constant torque on DC motor is shown in Fig 6 3 Open the file torque control mdl Assign suitable values to the PI current controller that was obtained from the previous experiment 5 Enter the value of Vd 42 and Ts 1e 4 at command prompt Build the model Ctrl B and start dSpace ControlDesk Open the sdf file and the layout file torque controllay setup the capture setting window View Controlbars Capture setting window as shown in Fig 6 4 and the connections are shown in Fig 6 5 63 Duty cycle a V motor Duty cycle b Duty cycle c Constant PWM Stop DS1104SL DSP PWMS3 3 PWM Control DS1104 ADC C5 motor current 2 Avg Block Enc position Enc delta position DS1104 ENC POS CI Encoder Master Setup DS1104 ENC SETUP 1 boolean SLAVE BIT OUT Reset Data type
52. e of the PWM voltage source They are generated by the DS1104 R amp D Controller board inside the computer DSI1104 R amp D controller Board and CP 1104 I O board In each discrete time step the DS1104 controller board takes some action to generate the digital control signals The type of action is governed by what we have programmed in this board with the help of MATLAB simulink real time interface This board monitors the input 1 e motor current speed voltage etc with the help of CP1104 I O board in each discrete time step Based on the inputs and the variables that need to be controlled 1 e motor speed or torque it takes the programmed action to generate the controlled digital signals The CP1104 I O board is an input output interface board between the Power Electronics Drive Board and DS1104 controller board It takes the motor current dc voltage etc from the Power Electronics Drive Board and also speed signal from encoder from motor coupling system to the DS1104 controller board In turn the controlled digital signals supplied by DS1104 controller board are taken to the Power Electronics Drive Board by CP1104 MATLAB Simulink and Control desk Programming DSI104 and control in real time Simulink 1s a software program with which one can do model based design such as designing a control system for a DC motor speed control The I O ports of CP 1104 are accessible from inside the Simulink library browser Creating a program in Simul
53. eck SD and Reset to make some measurements After you are satisfied with the data displayed go to the Capture Settings Window and press the SAVE button The dialog box will ask you to name the mat file that will contain the graphic data in all plot areas 34 Download the file br m which has instructions on plotting from the mat file and additional code to calculate the value of La and 4 from the graph Measure the voltage between terminals Phase Al and Bl using the DMM when the rotor is blocked hi Fk Edt Ww Toe Experiment Dirua Pai Parareter E CAM Wider Help k oe d Serr ee IU uM mdi a d m 47 s sngu x na zs V moator slua V motan alue motor cumce fCuri Sneed mmicut NENNEN 3 1 104 275 000 prctttgttc0gc ttgtt0 4g07 t4ptt07t7g4 077734 077a uasa Preeti M ahis Eelerence Capone apane VJ anablea Tao Save i mau E c E i i tH E T TH TE Juni tee phe Hotter umm PETENGE IEEE o Figure 3 8 Screen shot of dSPACE control desk 10 200 _ 150 5 D S 2 z gt 400 cL a a E T 450 ta in E p Bwin dp 0 T a 04 02 0 3 x m 0 01 02 0 3 Figure 3 9 Waveform of motor current and speed rpm as observed from the dSPACE control desk 35 3 5 Open loop speed control voltage vs speed characteristics In steady state with voltage V applied to the armature terminal of a DC motor following equation
54. en Platform Parameter Ete CAN Window Hep a GL 205 5 fg Vv NAS BB h 224 4 7 K OGu W a 10 000 0020 w pbhuMUWeepepfeo ndett SSS RUN NUM TENE 1459 e Y a 40 ph 300 200 100 rad_sec Out motor current Outi e speed _ ce E 1 0 0 2 O 4 0 6 0 8 1 0 1 2 1 4 1 5 1 8 2 0 E 1 0 0 2 0 4 0 6 0 6 1 0 ile 14 1 6 1 8 2 0 Figure 4 5 dSPACE ControlDesk Layout 47 dSPACE I O Board To INC 1 ENCODER 7 A DC Motor DC Motor Load Figure 4 6 Connections to determine J 4 4 3 Inertia determination In the Capture Settings Window View Controlbars Capture Setting Window the following modifications must be made Increase the display length to 2 seconds and change the Trigger Signal to SD Fig 4 7 Disconnect the LOAD motor from the Power Electronics Drive Board Check the SD control uncheck Reset and increase the voltage on the MOTOR to 15 V Record the speed and armature current I motor I 0 value at this operating point Uncheck the Shutdown button This will initiate the display process and after two seconds the speed plot will stop and a decreasing exponential curve will be obtained Fig 4 5 Press again the SAVE button in the Capture Settings Window and store the data in a file named j mat file Plot the mat file using exp4 plots m download this Calculate the value of J as explained in section 4 4 1 48
55. ent ADC DS1104ADC C6 dcmotor Idc Vit ADC In RMS larms DS1104ADC_C5 la_imotor error Vref_load Vref_PI duty Reset duty cycle generation DC duty cycle generation IM d3 Duty cycle a Duty cycle b Duty cycle c PWM Stop c2 DS1104SL DSP PWM3 PWM Channel 1 PWM Channel 2 PWM Channel 3 PWM Channel 4 DS1104SL_DSP_PWM1 Figure 9 6 IM Speed Control PI loop is unchecked upto 300 rpm RMS_Va_IM Varms Increase Wref RPM while keeping the motor in open loop speed control open closed Check open closed loop Now the motor is speed controlled Increase the value of Wref RPM till 900 and see if the speed is being controlled Save a screen shot of the speed control and attach it in your report controlled zero Stop the experiment in edit mode and close dSpace ControlDesk 96 Change the load torque Tref Do not go above 0 1Nm Check if the speed is being Reduce the speed back to 300 rpm uncheck open closed loop and bring Wref down to 9 5 Lab Report 10 points l Section 1 a Attach the torque speed characteristics generated in Matlab 3 plots along with Table 1 3 points b Comment on the graph how the torque speed characteristics change with frequency Slip 1 points c What is the value of Kr 7 point Section 2 a Attach the voltage current power
56. fixed x step box The output of this block is the motor speed in rad s However at low speeds there will be oscillations in the measured speed values Hence an averaging to get more accurate readings are needed Download the file Avg Block mdl and copy it to your folder Connect it as shown in Fig 3 1 The output of this block 1s the average speed in radians sec Add another Gain block rename this speed rpm in series with this to convert the rad s 60 value to RPM Change the gain value to ae TU Your real time model is now ready and should look like in Fig 3 1 EF gt Duty cycle a V_motor E 1 Vd dAdB Duty cycle b Gain2 Gain1 si Duty cycle c Constant dC PWM Stop DS1104S8L DSP PWM3 ADC E PWM Control DS1104 ADC C5 motor current la Enc position Enc delta position DS1104 ENC POS CI Encoder Master Setup DS1104 ENC SETUP Avg Block 2 pi Ts 1000 wm RPM Gain 5 Speed rpm Figure 3 1 Real time Model for Open Loop Speed Control of a DC Motor 27 Make the following changes simulation Configuration Parameters 9Solver Start time 0 Stop time inf Type Fixed step Solver odel Euler Fixed step size le 4 Optimization in Simulation and code generation uncheck everything except Implement logic signals as Boolean data Real Time Workshop System target file rti 1104 tlc Enter in command prompt gt gt Vd 42
57. fixed step size to 0 0001 o Simulation Configuration Parameters Real time workshop Set the system target file to rt11104 tlc o Simulation Configuration Parameters gt Optimization gt uncheck Block Reduction e Set Vd 42V in the Matlab command prompt 20 m e Duty cycle a 1 Vd 2 s Duty cycle b Gain1 Duty cycle c Constant PWM Stop m DS1104SL DSP PWM3 PWM Control Figure 2 6 Control of a two pole switch mode converter in real time Once the real time model is ready it can be implemented on the DSP of DS1104 by building the model As explained in experiment 1 building the model will broadly cause 1 Compilation of C code generated by Simulink and its hardware implementation on DS1104 2 Generation of a variable file with extension sdf that allows access to the variables and signals in the real time Simulink model e Build the Simulink model by pressing CTRL B Observe the sequence of events in the Matlab command window e Once the real time model is successfully built open Control Desk icon on PC Desktop e Using the File menu create a New Experiment and save it in the same working root as the real time Simulink model Create a New Layout using the File menu again Two new windows will appear in the Control Desk workspace The one called Layout1 will contain the instruments used for managing the experiment The second window is a library which will let us drag and drop the necessa
58. gt ent Directo cs Documents and Set Ef Ei T 1 AllFiles ssi Files File C expl lay LAY Fi File Edit View Help Doe tind qm Signal Generator Output various wave forms gt gt pwd ans E oe Simulink E 2 Continuous 2H Discontinuities 0 BH Discrete i 0 BH Look Up Tables E BY Math Operations o b H Model Verification 0 r Model Wide Utilities 0 cB Ports amp Subsystems Band Limited White Noise Chirp Signal Clock Constant Po il Exp1 nal Model 2H Signal Attributes 529 i Digital Clock POE 23 Signal Routing wet eee Bione ee if 7 X o 22H Sources 3 zx o i H User Defined Functions Look in CX Expl e amp G Es S Control System Toolbox B Wl Fixed Point Blockset H ll Real Time Workshop E li S Function demos So uj GR SimPowerSystems E B Simulink Extras H IA dSPACE MotionDesk Blockset TR E ll dSPACE RTI1104 B gt D51104 MASTER PPC 2 File name Exp1 mdl BA SERIAL mn Ee D51104 SLAVE DSP Files of type Model mdl Cancel oo Be Extras oo BH TaskLib Repeating Sequence Signal Generator Signal Builder Pa Sine Wave distat ll ci ed Amatas HE Library Brow eT Box i INduction Motor Exp BA enm Figure 1 4 Opening the Simulink file Expl mdl changing the path of current working directory e The Simulink file Expl mdl will look as shown in Fig 1 5 Open the s
59. hange in isq e Vary the value of theta initial by 10 and observe the change in speed Does it increase or decrease e Check if it s possible to reverse the speed of the motor without changing the value of theta initial 7 5 Run the motor with speed control Optional In this section the speed controller generates a reference value for isq The speed controller can be designed using the parameters in Table 1 or just the values of Kp w and Ki w listed in Table 2 In the provided model file the direction of rotation is taken positive the value of theta initial must be the one that corresponds to positive speed Tablel PMAC Motor Parameters Parameter Value 0 6253 4 4797e 4 0 0924 s po Table 2 PMAC Motor PI Controller Values Parameter Value 37 4179 0 0268 78 1 The connections for the real time implementation are in Fig 7 6 2 Open the file PMAC current mdl Enter the values for Kp 1 Ki 1 Kp w Ki w theta intital Vd 42 poles 4 and Ts le 4 at the MATLAB command prompt The model is shown in Fig 7 8 Index DS1104ENC HW INDEX C1 ENCODER SET POSITION DS1104ENC SET POS C1 EncPos Theta da theta initial y theta initia theta initial Subsystem Enc position e Wm2 Enc delta position gt W mech RPM In1 Go to 2 DS1104 ENC POS CI Speed Measurement ENCODE
60. has access to the variables of control system through Exp1 sdf hence the control desk can read the port INC1 modify the data and send it back to any of the output port of CP 1104 if necessary Motor current reference speed and actual speed can be observed in the same manner the communication among components is same as explained above Note that in this demonstration we are only observing the variables of control system such as speed of the motor and current It is also possible to change the variables of control system in real time from the control panel In the future experiments this will be done to give a reference speed command to run the motor at a desired speed This reference speed command will be changed in real time to change the speed of the motor Sequence of events when Start button is pressed on the control panel DS1104 will be commanded to generate the controlled digital signals as per the speed and phase current of the motor in real time The information about the speed and current of the motor 1s available to DS1104 via CP 1104 which is connected to the Power Electronics Drive Board for current feedback and Motor coupling system for speed feedback o The controlled digital signals will be received by CP 1104 from DS1104 Digital I O of CP 1104 is connected to the Power Electronics Drive Board hence the board will start generating the PWM voltage source o The motor will receive the PWM voltage at it
61. hase induction motor will be characterized to determine the various parameters used in its per phase equivalent circuit The circuit diagram for this experiment is shown in Fig 8 1 where a DC motor is coupled to the induction motor under test DC resistance test will be done to determine the value of Rs The magnetizing inductance Lm gt gt Lis will be calculated by running the induction motor at synchronous speed at rated voltage and rated frequency Speed of the DC motor coupled to the induction motor will be controlled to run the induction motor at synchronous speed The rotor circuit parameters i e Ly and R will be calculated by blocked rotor test while injecting slip frequency at the stator terminals Note 1 The induction motor can get hot especially in the blocked rotor test Please turn off the power when you are not taking any readings Note 2 The speed is measured from DC motor Vs J Figure 8 1 Per phase equivalent circuit of a three phase induction motor Download the file Lab 8 Summer 2011 zip and extract its contents to a folder on the desktop Start MATLAB and change the working directory to the folder containing all the extracted files 82 8 2 Determine Rs Measure the resistance between any two terminals of the induction machine and the resistance of the multi meter leads Subtract the resistance of the leads to get the resistance between the two terminals which is twice of Rs Calculate the value of
62. hat can be modified by double clicking on the blocks Double click on the Repeating Sequence block and edit the properties as o Time values 0 0 5 fsw l fsw o Output values 0 1 0 Where fsw is the switching frequency 10 kHz set as a global variable in the Matlab prompt Type gt gt fsw 10000 Add a Scope to the model from Simulink Sinks Connect the output of Repeating Sequence block to the input of the Scope The simulation model is now ready However before running the simulation parameters need to be changed Go to Simulation menu and select Configuration Parameters Set the parameters to the following values o Stop time 0 002 o Fixed step size 1e 6 o Solver Options fixed step odel Euler Run the simulation by clicking on the triangular button on the top Double click on the scope 15 after the simulation finishes The result should look similar to the one shown in Fig 2 2 2 3 2 Duty Ratio and Switching Function For a desired average output pole voltage v an the control voltage venria is given by equation 3 Equation 3 is implemented in Simulink and the control voltage thus generated is compared with the triangular signal generated in the last part inixi BETTER lolx File Edit View Simulation Format Tools E o 9 p d Eg a E Help i co ed IE MESA Repeating Sequence F 100 ode Zz Time offset Figure 2 2 Triangular Waveform with 10 kHz frequenc
63. he values of Kp 1 Ki 1 theta intital Vd 42 poles 4 and Ts le 4 at the MATLAB command prompt The model can be seen in Fig 7 7 DS1104ENC HW INDEX C1 ENCODER SET POSITION Theta da calculations DS1104ENC SET POS C1 EncPos Theta da theta initial theta initial theta initial Subsystem Enc position gt Wm2 W mech RPM In1 Enc delta position f Go to 2 DS1104 ENC POS CI 4 Speed Measurement Go to ENCODER MASTER SETUP DS1104 ENC SETUP Bites m c3 uly Cy Switch Duty cycle b 5 3 Duty cycle c d_lim DC_CMvoltage DS1104SL_DSP_PWM3 c fo Gurrent controller abc gt dq Duty ratio generation for locking the rotor Product Current reference Current sensing feso From 1 Isdq vad Vsdq ref reset 2 vsq V abc To start the system Subsystem1 1 Uncheck Lock 2 Uncheck Reset metazoa 4 set the reference Isq 0 5 A on no load From 2 dqoabc 5 note that fs 50 KHz 1 Resetlnteg 1 Oe const Go to 1 Figure 7 7 Simulation model PMAC current mdl e Build Ctrl B the mdl file e Open dSpace ContrlDesk and open the variable file PMAC current sdf Open the file PMAC current lay e Uncheck Lock TI e Uncheck Reset e Increase the value isq the q component of the stator current to 0 5 e Observe how the speed changes with c
64. heck Torque SpeedControl so that the DC motor runs under torque control Slip v f Control Torque SpeedControl e Increase the value of ref frequency slowly upto 30 Hz If the dc motor speed w mech RPM is negative the phase sequence is correct If the speed is positive interchange any two terminals after bringing the speed back to zero of the induction motor e Note down the speed of the motor Can you estimate the number of poles of the induction motor e Reduce ref frequency back to zero and stop the experiment in edit mode dSPACE I O Board To INC 1 ENCODER 3 phase Induction Motor DC Motor Load Figure 8 3 Connections for characterization of three phase induction motor 84 8 3 2 Lm In this section the DC motor is run under speed control at the rated speed and the induction motor 1s supplied voltages at rated frequency so that the motor slip is zero Go to animation mode Slip v f Control Torque SpeedControl Increase the speed of the dc motor Wref to 1800RPM 60 Hz electrical Increase the value in ref frequency numerical input box to 60 Hz Observe induction motor phase a voltage and current in controldesk set length to 0 2 in capture setting window Save this waveform as vi unloaded mat Using these waveforms the value of Lm can be
65. ide motor to Phase A2 and Phase B2 and connect the DMM to the load side motor Always ramp up the voltage or you may get a fault Adjust the LOAD voltage reference such that the MOTOR current takes the following values at each voltage 10 1 2 3 4 5 A Make sure that neither motors draws more than 5 A If V motor is set to 10V set V load to 10V at the start to prevent overcurrents Record the motor speed _rad sec the LOAD current IL and LOAD voltage V load required to obtain the specified MOTOR currents All current measurements will be multiplied with k to obtain the corresponding torque values as per equation 2 The sign of speed will be positive for the motor with the encoder and opposite for the motor without encoder Draw the MOTOR and LOAD characteristics using the data acquired during the measurement process 43 Table 1 Torque Speed Characteristics V motor V V load V Measured by Measured by DMM 4 3 Open Loop Control of DC Motor without Load to calculate B and Tiction For determining the friction parameters the MOTOR will be run under no load conditions as done in the previous experiment Experiment 3 Since the MOTOR has to overcome only friction Ty 0 the electromagnetic torque Te kgI will follow the linear friction model see equation 3 in steady state Fill in the TABLE 2 using the values obtained in experiment 3 Plot the values of speed X axis vs Te and find the slope of
66. imulation parameters from the tools menu and set the parameters as shown in Fig 1 5 The fixed step size 1s the same as the discrete step which will be used by the DSP DS1104 This means that in every discrete step the whole program i e control system in this case will be executed I O data will be exchanged and the decision making will be done inside DS1104 e Type Ts le 4 in the Matlab prompt Press CTRL B to build the control system in real time now Refer to Fig 1 6 note the sequence 1 Compilation of C code that 1s generated by Simulink which will be used to implement control system in hardware DS1104 2 Generation of Expl sdf file which will be used later on by Control desk to access the variables of control system file dk View Simulation Format Tools Hel D ce a om nos a Be Rote DS IAEN SETUP wrer 4quad 5npeed Measurement PME Chant 2 NT ipe Ft Channal Pl Current MM Reset Duty Cycle Generation lol xl Sow wiskspace un Dinonosics Advanced RealTime werkshop d3 DS81104ADC C5 Gan a zd State 00 Sip me ini Type Foed ctep odes unge una MM a al Feed step tize 0 000 Mode Auto petii 1 5 D 3 j a 3 PA sd FTU dinars c s o ooo ooo B RAF AY SE ME YRLUEC E Wm Loi Ws goes oca BP Curent Diecon ELLE con ELE CES m GE c mes Foe SIER SETUP J 1 WORE DI
67. ink and the procedure to use the I O port of CP 1104 will be detailed in future experiments At this stage let us assume that we have created a control system inside the Simulink that can control the speed of a DC motor When you build the Simulink control system pressing CTRL B by using real time option it implements the whole system inside the DSP of DS1104 board i e the control system that was earlier in software Simulink gets converted into a real time system on hardware DS1104 Simulink generates a sdf file when you build CTRL B the control 3 system This file gives access to the variables of control system like reference speed gain tuning the controller etc to separate software called Control desk In this software a control panel see Fig 1 3 can be created that can change the variables of control system in real time to communicate with DS1104 and hence change the reference quantities such as the speed or torque of the motor 1 3 Demonstration of Speed Control of a DC motor The system for the speed control of a DC motor is shown in Fig 1 3 Note that the currAT i e phase current of DC motor and encoder signal speed of DC motor is fed back to the DS1104 board via CP 1104 The requirement of feeding back phase current and speed of the motor will be studied in Experiment 4 For now assume that these two quantities are required to control the speed of DC motor Perform the following steps to run the experiment The co
68. le when you build CTRL B the control system This file gives access to the variables of control system like reference speed gain tuning the controller etc to separate software called Control desk In this software a control panel can be created that can change the variables of control system in real time to communicate with DS1104 and hence change the reference quantities such as the speed or torque of the motor 1 7 Motor coupling system This system has a mechanical coupling arrangement to couple two electric machines as shown in Fig 10 It also has an encoder mounted on the machine that is used to measure the speed and for close loop feedback speed control of the motor The motor that needs to be characterized or controlled is mounted in this system The motor under test MUT whose speed torque needs to be controlled could be either a DC motor or three phase induction motor or three phase permanent magnet AC PMAC motor The motor demands a controlled pulse width modulated PWM voltage generated by Power Electronics Drive Board ee Eii F poera Figure 10 Motor Coupling System showing DC Motor DC Generator and Encoder 111
69. lity 1s proven increase voltages or power stopping at frequent levels to check for proper functioning of circuit or for any components is hot or for any electrical noise that can affect the circuit s operation 1 3 5 Precautions while switching off or shutting down the circuit Reduce the voltage or power slowly till it comes to zero Switch of all the power supplies and remove the power supply connections Let the load be connected at the output for some time so that 1t helps to discharge capacitor or inductor if any completely 1 3 6 Precautions while modifying the circuit Switch Off the circuit as per the steps in section 3 5 Modify the connections as per your requirement Again check the circuit as per steps in section 1 3 3 and switch ON as per steps in section 1 3 4 100 1 3 7 Other Precautions No loose wires or metal pieces should be lying on table or near the circuit to cause shorts and sparking Avoid using long wires that may get in your way while making adjustments or changing leads Keep high voltage parts and connections out of the way from accidental touching and from any contacts to test equipment or any parts connected to other voltage levels When working with inductive circuits reduce voltages or currents to near zero before switching open the circuits BEWARE of bracelets rings metal watch bands and loose necklace if you are wearing any of them they conduct electricity and can cau
70. lock The switching power pole building block has been explained in Section 1 6 1 of 1 Depending on the position of the bi positional switch the output pole voltage v is either V or 0 The output pole voltage of the power pole is a switching waveform whose value alternates between V and 0 depending on the pole switching functionq The average output voltage va of the power pole can be controlled by controlling the pulse width of the pole switching functiong T vA ai d V 1 S Typ pulse width of q4 T switching time period 2 2 2 PWM of the Switching Power Pole As seen in section 2 2 1 in order to control the average output voltage of the switching power pole the pulse width of the pole switching function q needs to be controlled This is achieved using a technique called Pulse Width Modulation PWM This technique is explained in section 12 2 1 of 1 To obtain the switching functiong a control voltage v is compared with a triangular entr a waveform vq of time period T Switching signal q 1 if v gt vq 0 otherwise As in 1 entr a Ventrla 7 da Vai 2 Using equations 1 amp 2 and assuming Vas 1V VaN Ventrla 7 V 3 d Where van VA average pole output voltage with respect to negative DC bus voltage 13 2 2 3 Two pole DC Converter The two pole switch mode DC converter utilizes two switching power poles as described in the previous sections The output
71. mate the voltage required to maintain the same speed using eq 1 amp 2 Verify this value displayed in Control Desk BONUS Give a sinusoidal disturbance of 0 05 Nm in load torque over a constant value of 0 15Nm use frequency of 1Hz Observe how the control system responds to the disturbance 68 4 ponies SLAVE BIT OUT Reset Data type Conversion 2 DS1104 SL_DSP_BIT_OUT_C10 oss 15 on fo PWM Channel 1 B step Switch Torque_ref la ref o PWM Channel 2 Tinitial PWM Channel 3 ADC PWM Channel 4 D L DSP _DS1104 ADC C6 motor current 1 Constant 1 xL E Ag a 1 Tem actual Duty cycle a PI Speed reset Duty cycle b gt e os DS1104 ADC_C5 motor current constant PWM Stop DS1104SL DSP PWM3 PI Current reset1 Gain2 X Avg Block PWM Control Enc position Enc delta position 2 pi Ts 1000 DS1104 ENC POS CI Wm dist Wm Gain 5 motor speed Encoder Master Setup DS1104 ENC SETUP Figure 6 8 Simulink model file for speed controlled DC motor with torque controlled load Torque ref Out1 w_ref Value Reset Value 0 150 125 000 P lv Check hd Y H 0 Length 1 Iv Auto Repeat Downsampling 1 EZ Trigger Signal 125 664 0 290 eor N Level 0 5 Delay 0 Model Root Torque step Value Reference Capture Capture Variables Take Save 002 of 002 Tem_act
72. ment you will plot the torque speed characteristics of a DC motor using the second motor as load For a constant V motor voltage the load is varied using V load The motor current and speed are recorded in a table A set of measurements is obtained for different supply voltages The steady state mechanical characteristics of a DC motor are the dependency between the electromagnetic torque N m and the electrical speed rad s Since the dependency 1s linear the characteristics will be straight lines for the entire voltage range 0 V 4 4 and is independent of the load The motor equations reflect this linearity Vmotor Rala Kgo 1 d kyl 2 The steady state model for the load can be approximated with a friction type model where the torque is proportional to the speed and a constant friction torque is always present Te T Bo Teriction 3 where all terms in the right hand side are load related For our setup where the load is a voltage controlled DC machine the load torque Ty is in fact the electromagnetic torque developed by the second DC motor 42 dSPACE I O Board To INC 1 ENCODER 7 A DC Motor DC Motor Load Figure 4 3 Connections for torque speed characteristics 4 2 4 Drawing the torque speed characteristics Make connections as per Fig 4 3 Maintain the MOTOR voltage at constant levels 10V and 15V measure the actual motor voltage using DMM Turn off the power Now connect the load s
73. mmunication between the four components explained in section 1 2 is detailed in each step wherever necessary Control desk provides a bi directional communication between its control panel and DS1104 CP 1104 zx From ENCODER 4 e INC 1 J Slave I O 1 PWM Control desk P CURR A1 42 V DC Power Supply MATLAB E Simulink N Power Electronics Drive Board A1 B 1 vod o DS1104 R amp D Controller Card To INC 1 on CP 1104 Computer ENCODER e Figure 1 3 Demonstration of DC motor speed control 4 e Connect the circuit as shown in Fig 1 3 You are given with files Exp1 mdl Simulink control system file and Expl1 lay control panel in Control desk Create a new folder on desktop as Exp1 and bring these two files into that folder Open MATLAB Simulink and set the folder Expl as the path of the current working directory Verify in the command window for the correct path Fig 1 4 Open the Simulink file Exp1 mdl as shown in Fig 1 4 MATLAB fe xj File Edit View Web Window Help b E l amp A o c i 9 ibe Directory and Settings 2 270 Desktop Exp1 Md F 21x m T L7 By Stade Base gt j Nane size Bytes co MTs lxl 8 act C Documents and Settings 2 270 Desktop Expl lxl B dew b gt
74. nd in the negative direction for some time 1 e the direction of rotation alternates Right click on the graph and select edit capture setting and set the capture setting as shown in Fig 1 9 en 3 xi Look in C Exp e amp merE expl rti1104 File name esp lay Files of type Layouts lay 4 EER exp Yariabe size Type Origin Description ED Model Root finalTime ixi FloatIeee Simulation j Labels currentTime 1x1 FloatIeee Current si H E Task Info modelStepSize 1x1 Floatleee64 Fixed step simState 1x1 Int32 Simulation errorNumber ixi UInt32 Error num rti amp ssertionMode ixi Int32 Assertion i4 4 P TRIN Log Viewer A Interpreter File Selector A c documents and settings 2 270 desktop exp 1 exp1 sdf For Help press F1 EDIT huM 06 07 2007 18 28 if istar 756 nn Amatas El Simulink Library CuPanderaBex ytnduction Motor WiExet controlDesk p OF 6 28PM Figure 1 7 Control desk panel opening the layout oo Selector Y AnimatedNeedle pui Bar EH CheckButton RPM pai Display f Frame BA Gauge y InvisibleS witch WW mech Wref 4quad Out1 Motor Current Out1 Bhd Message D E m D z T D a I A MultiStateLED E Numericlnput Fa OnOffButton EY PushButton SE RadioButton E LED s Automotive Measurement Custom Instruments Reset value Reset Integrator
75. ock include B 2 points Attach simulation output of current response for a step input of 1A 7 point Attach simulation output of speed response for a step input of 200 rad s from a constant value of 100 rad s 1 point All the responses required for questions 2b and 2c are based on step change in reference signals These are required more for design purposes In practical applications it is more important to know how the system responds to disturbances in load torque In the simulation give a step load torque of 0 3 N m while maintaining a constant speed of 200 rad s Observe the response in current and speed and attach the plots 7 points 3 Section 5 4 Attach the speed and current response for a step change in speed reference as observed through control desk for a step change from 100 rad sec to 300 rad sec 3 points 5 6 References 1 ELECTRIC DRIVES an integrative approach by Ned Mohan 2000 MNPERE 60 Experiment 6 Four Quadrant Operation of DC motor 6 1 Introduction In the previous experiment you controlled the motor to run under speed control The objectives of this experiment are 1 To observe the four quadrant operation of a DC motor 2 To control a motor under torque control 3 To couple the speed control motor and torque controlled motor and observe the effect of a stepped torque 6 2 Four quadrant operation of a DC motor The four quadrant operation is performed by giving an alternating
76. only Phase Al B1 for powering while three phase motor needs three phases Al B1 Cl A1 C B1C eJ A2 B2 ex 7 420 sd aE GND PWM PWM INV 1 INV 2 Figure 1 Block Diagram of Electric Drives Board 102 TTE LACE E LE R et ay Perr Drives Board 1CS Power Electroni Figure 2 103 Table 1 Locations of components on Power Electronics Drives board NO Mo Lj MS MEA E P Lae ons on on Lae ER ES E EA Ea BES a BES EES Ea BES ES om ES om EE NS ox BES EE ERN EES Component Terminal 42 Terminal GND Terminal PHASE A1 Terminal PHASE B1 Terminal PHASE Cl Terminal PHASE A2 Terminal PHASE B2 Terminal PHASE C2 DIN connector for 12 V signal supply 10 l Signal supply switch 1 Signal supply 12 V fuse 12 Signal supply 12 V fuse 13 4 Signal supply LED 1 MOTORI FAULT LED 15 6 MOTOR2 FAULT LED I DIGITAL POWER LED M 7 8 9 0 l MAIN POWER LED 1 Inverter 1 1 Inverter 1 2 DC Link capacitor of Inverter 1 2 DC Link capacitor of Inverter 2 N 2 3 4 Driver IC IR2133 for Inverter 1 2 Driver IC IR2133 for Inverter 2 2 Digital Supply Fuse 25 dSPACE Input Connector 6 7 8 9 30 31 3 3 3 3 3 2 RESET switch 2 Phase A1 current sensor LEM 2 Phase B1 current sensor LEM 2 Phase A2 current sensor LEM Phase B2 current sensor LEM DC link current sensor LEM 2 3 4 VOLT DC CURR
77. or num rti amp ssertionMode Int32 Assertion L4 4 P ei Log Viewer A Interpreter A File Selector A c documents and settings 2 270 desktop exp1 exp1 sdf For Help press F1 RUN Mmm 06 07 2007 18 32 distat C e d I f MATLAB Agi Simulink Library Pandora Box yINduction Motor Wi Expi i2 ControlDesk D m 6 32 PM Figure 1 10 Motor actual speed red reference speed green and phase current blue 10 1 4 Lab Report and Reading assignment List the sequence of events 1 e the communication between the four major components when STOP button is pressed in the control panel For this experiment draw a flowchart indicating step by step procedure to create a real time model in Simulink which 1s followed by controlling a DC motor from control desk study thoroughly appendix A pay special attention to the Power Electronics Drives Board features Make a note of voltage and current scaling in the drive board Draw a block diagram of Power Electronics Drives Board indicating the inputs like power supplies digital input resets etc and outputs like PWM voltage motor current dc bus voltage etc 11 Experiment 2 simulation and Real time Implementation of a Switch mode DC Converter 2 1 Introduction In the previous experiment a demonstration highlighting various components of the electric drives laboratory was performed Real time simulation file mdl and a
78. ource thus generated 1s connected to the motor coupling system as shown in Fig 1 2 CP 1104 I O board _ ADC and DAC interface Digitial I O Encoder interface and RS232 cQ Ww A A x l Motor Current DC Voltage 2db Control desk MATLAB Simulink 42 V DC Power Cc 42 V etc for feedback control Power Electronics Drive Board Slave 70 PWM CURRA1 CURRB1 VOLT DC CURR A2 CURR B2 DS1104 R amp D Controller Card Computer Communication between Control desk and Hardware in real time Ho H Motor coupling system ENCODER E To INC 1 INC 2 on CP 1104 Figure 1 1 DSP based electric drives laboratory system DC Generator Figure 1 2 Motor Coupling System showing DC Motor DC Generator and Encoder Power Electronics Drive Board This board has the capability to generate two independent PWM voltage sources A1IBICI and A2B2C2 from a constant DC voltage source see Fig 1 in Appendix Hence two machines can be controlled independently for independent control of variables at the same time This board also provides the motor phase currents dc bus voltage etc to control the motor for a desired speed or torque To generate the controlled PWM voltage source this board requires various digital control signals These control signals dictate the magnitude and phas
79. perform the experiment The objective would be to understand how maximum electromagnetic torque from the motor is achieved when stator current space vector is maintained perpendicular to the rotor flux vector This angle is changed in real time to verify the decrease in electromagnetic torque This experiment is divided into three parts 1 Observe the back emf of the motor and calculate its back emf constant 2 Runthe motor with current control by correct placement of the current space vector 3 Run the motor with speed control 7 2 Theory Space Vectors dq windings In a 2 pole motor with sinusoidally distributed stator windings as shown in Fig 7 1 the current and voltage space vectors are given by 1 and 2 as in reference 1 i t i t Z0 i t 2120 i t Z240 1 v t v t Z0 vp t 7120 v t 240 2 For dynamic analysis and control of ac machines two orthogonal axis d amp q can be defined such that windings along these two axis can generate the same mmf as the three sinusoidally distributed windings 2 These dq windings can be at some arbitrary angle 04 with respect to the phase a axis In this case the d axis winding 1s taken to be along the rotor axis The transformation from abc frame to dq frame is given by 3 for the currents The same equation applies for voltages as well where Oaa is the angle between the rotor and the a axis 2x 2c cos cos Q cos 0 I I m da 3 da 3
80. r what are the values of duty cycle da and db for a dc bus voltage of 50V Also what will be the dc bus current point 50 Experiment 5 DC Motor Speed Control 5 1 Introduction In experiment 3 and 4 the speed of the DC motor was controlled by using an open loop voltage control The purpose of this experiment is to design and implement a close loop speed control of a DC motor drive We shall use the same DC motor for which the parameters were calculated in the previous experiment At first the controllers will be designed and tested on a simulation model of the DC motor Once the parameters are tuned the model of the DC motor will be replaced with the real motor The tuned controllers will be implemented in real time on DS1104 to perform the close loop speed control of the DC motor 5 2 Simulink Model of the DC motor The model for a DC motor in frequency domain is derived in Chapter 8 1 _ Va s E4 S E E s kg s 1 On 9 85 L0 Ton 8 kyl s kr kg 2 eq Equations 1 and 2 can be easily implemented in Simulink using standard blocks as shown in Fig 5 1 e Download the Simulink model de_motor mdl to the desktop Fig 5 1 Convince yourself that it is the model for a dc motor e The representation in Fig 5 1 uses integrators instead of transfer functions This allows setting the initial conditions for the current and speed state variables The model also includes the friction coefficien
81. rent controller with reference current as 2A results similar to the Fig 5 4 b and Fig 5 4 c will be obtained Set the value of Kp 1 and Ki 1 in Matlab prompt or in the m file dc motor parameters Also set the values of lim 1 Kpwm 42 Ia ref 1 Run the m file before running the simulation which will load the values of all the variables Run this simulation for a reference current of 1 A for 0 005 sec fixed step odel time step 1e 4 Save the plots for the report Once the response in current is considered optimal low overshoot fast rise time zero steady state error the speed controller can be designed For designing the speed controller you can assume B 0 but while building the Simulink block include B A similar PI controller for the speed loop PI Speed will be added to the Simulink model Design the speed controller for a bandwidth of 10Hz 62 83 rad sec Phase margin 60 deg Follow the procedure described in 8 7 2 1 to design the speed control loop using the motor parameters determined in earlier experiment 54 la la ref P Current Load Torque DC Motor Terminator a Simulink model for current controller For example the current amp speed waveform for a reference current of 2A are as given in Fig 5 4 below la la_ref 922 hae as Time offset O Time offset O b Current waveform for 2A current reference c Speed waveform for 2A current referen
82. roller Design Once the DC motor model is built the controllers can be added and tuned Start with the current loop for which a PI controller is required e Download the file components mdl All the necessary blocks can be copied from here For the more adventurous follow the instructions as specified in points a b and c to build it a Build the model for a PI controller see Fig 5 3 Double click the integrator block and enable limit output Then set the Upper and Lower saturation limits to lim lim The lim value should be set to 1 in the m file as the absolute maximum value of control voltage is 1 which is the input to Kpwm block The resultant maximum value of voltage applied to the DC motor will be 42 which is the rating of the DC motor b The armature current is fed back to the controller input ea DE 2 D D pr la ref Kp i Saturation 1 amp MUN Ki i J Integration Figure 5 3 PI controller model 53 c The Saturation block sets the maximum and minimum limits for the control voltage in our case 1 Design current controller for a bandwidth of 100 Hz 628 3 rad sec phase margin 90 deg The parameters of the PI controller namely Kp 1 and Ki 1 are computed using the motor parameters which were evaluated in the earlier experiment This procedure 1s described in section 8 7 1 1 Create the file for a current controlled DC motor as shown in Fig 5 4 a Running the Simulink model for the cur
83. rrespective of load torque variations Let us say you have to maintain the speed of the motor at 150 rad sec 1 Setup the experiment as shown in Fig 6 5 2 Open the file torque control w control mdl Your model should look like Fig 6 8 In this model inverter 1 controls the motor with speed control and inverter 2 controls the second motor load with torque control Note that these motors are identical Assign the values to all the PI controllers run the m file which contains all values the values of Kp and Ki are obtained from the previous experiment 3 Build the model Ctrl B and restart dSpace ControlDesk Open the sdf file and open the layout file torque control w control lay 67 10 11 12 13 In the capture setting window set the length to 1s and level to 0 5 Drag Torque step value to the gray box such that Model Root Torque step Value is displayed there Check On Off Ramp up the speed to 150 rad sec Give a step change in load torque from 0 to 0 15Nm and note the resultant speed Capture this waveform Fig 6 9 Theoretically estimate the voltage required to maintain the same speed from the equations 1 and 2 Verify this value displayed in Control Desk The duty ratio value is displayed in the control desk Estimate using that Change the direction of rotation 150 rad sec Give a step change in load torque from 0 to 0 15 Nm and note the resultant speed Theoretically esti
84. rug BY X4 4M marc 9 daa 55K Ome x Sms AE ptas abae y quoe hz e ye al 12 on I H amp Targa muti speed radpeciChi T 132 209 m actuai Out 0 147 Figure 6 6 Modeling of a constant load The torque Tem and speed of the motor can be viewed on the controldesk window as in Fig 6 6 Part b Modeling of a crane load Modeling of a crane load constant load torque is done in Part a for lifting action In this part the crane is used to lower the heavy load 1 e the load torque retains the same direction but the speed reverses 1 Set up the experiment as shown in Fig 6 5 The response of torque and speed can be seen in Fig 6 7 2 Use the given simulink model torque control mdl and the layout file torque control lay 3 Apply a constant voltage to the dc motor of value 12V to make the motor rotate in opposite direction 4 Note down the speed of the motor 5 Give a step change in load torque from 0 to 0 15N m and note the resultant speed 66 6 Theoretically estimate the speed in rad s 7 What is the net power supplied by the motor What is the quadrant of operation kr Ct Yee Ton Coed ietruertiaer Fete Pewee fio CAH ie ep Meu BY 5 QW omar cc 9 Raa 4 x Og EL ag A cee A Fe Sete fe eee crt Y Figure 6 7 Modeling A Crane Load 6 4 Closed loop speed control In speed control the motor speed is maintained constant i
85. ry dSPACERTII 104 DS1104 MASTER PPC DS1104ADC C5 e Connect a Gain block at its output and set its value at 20 e Connect a Terminator at the output of the Gain block rename this block motor current and label the signal as Ia 3 2 2 Adding speed measurement blocks To measure speed we shall use the DS1104ENC POS C1 block from the dSPACE library This block provides read access to the delta position and position of the first encoder interface input channel The delta position represents the scaled difference of two successive position values of a channel To receive the radian angle from the encoder the result has to be multiplied with 2TU 2TU where encoder lines is 1000 for the encoders used in the laboratory setup encoder_lines 1000 The delta position scaled to a radian angle has to be divided by the sampling time to obtain the speed as in dO AO AO dt ty tk T e Drag and drop the DS1104ENC POS C1 block from the dSPACE library In addition the encoder set up block DS1104ENC SETUP is to be added to the model Both these blocks are in dSPACERTII104 DS11DS1104ENC POS C104 MASTER PPC 26 Connect a Terminator block to the Enc position which is located in DSIIO4ENC POS Cl Simulink Sinks Terminator Connect a Gain block at Channel 1 output 1 e Encdelta position and set its value as 2n Ts 1000 where T is the sampling time set in the simulation parameters under the
86. ry controls for the experiment into the Layout You can also open the existing exp2 lay file from Lab2 Summer2011 folder e Now select File gt Open Variable File Browse to the directory containing the real time Simulink model Open the sdf file e g For Simulink model named twopole mdl the variable file will be twopole sdf 21 e After opening the variable file notice that a new tab in the lower window called Variable Manager appears below the layout Fig 2 7 The variables of the real time Simulink model file are under the tree Model Root Expand Model Root observe the variables and relate them with the real time Simulink model et Fis de Wee Too opened funme Paton Paneis Rr CAN inion Help 0 x k tur ie tS oR Q mE mbr rs FEA AE TR Ouran rni rr aL For reip press P EWT Num Wurm 149 Figure 2 7 New Layout Window for Instrumentation and Control e Now a user interface that allows us to change input variables amp system parameters in real time and also observe signals will be created The input variable in this experiment is the output voltage of the switch mode converter The duty ratios generated by the Duty Ratio Calculator will be the signals that will be observed in the layout The actual pole voltages will be observed directly from the power electronics drives board using an oscilloscope e In order to change the reference output voltage and observe the duty ratios suitable parts need to be adde
87. s as in Fig 9 wn owe 2 DTT INT O swm 9 IJOT8 INT3 O SPWMS re l 1019 INTA O SPWMA d T ssTe Iw srwWwS 4 E r sax SPWMS O mo Q SSMO 3 sewer O prime 1 ssomi Spwe s X indes 1 om 2 oe mei TXD swns O Phoa M cll m3 m3 um A i DCD CTS ST2PWM Ww index 2 a UA acd enves scare a DSR RXD Scare NE scapa j q Z Slave I O PWM UART Ports EB Status Indicators Figure 8 CP 1104 Board SADC Ponts f DAC Pons F xu uu E x j i a i Li TTE N 4 a 4 ra L i Figure 9 a CP1104 ADC and DAC Ports Figure 9 b PWM port INC for Encoder 110 1 6 MATLAB Simulink and Control desk Programming DS1104 and control in real time simulink is a software program with which one can do model based design such as designing a control system for a DC motor speed control The I O ports of CP 1104 are accessible from inside the Simulink library browser Creating a program in Simulink and procedure to use the I O port of CP 1104 will be detailed in future experiments At this stage let us assume that we have created a control system inside the Simulink that can control the speed of a DC motor When you build the Simulink control system CTRL B by using real time option it implements the whole system inside the DSP of DS1104 board i e the control system that was earlier in software Simulink gets converted into a real time system on hardware DS1104 Simulink generates a sdf fi
88. s terminals and hence start rotating It will speed up the current in the winding will increase Since the speed and the current of the motor thus increased are fed back to DS1104 1n real time the DS1104 will take the next action as per control system DS1104 will change the pattern of digital signal to change the speed of the motor such that the motor will achieve the speed as commanded in the control system block Wref 4quad Note that the speed command in control system is alternating hence the motor alternates its direction of rotation The instantaneous motor speed and current is shown in Fig 1 10 i ControlDesk Developer Version exp1 8 xj he File Edit view Tools Experiment Platform Instrumentation Parameter Editor Window Help I x e Sui seere ILES RE aan gt a loc x s m m i n c 8 t n le eles 4 4 y x 04 200 200 d hj ii z 02 1001 10076 o E t y oH og 915 E dl 2202 D o 5 1001 amp 100 is 0 4 ua id 200 200 E 0 6 300 300 08 400 400 10 500 500 2 0 E a a E 0 1 20 30 40 Speed MeasurementA mech RPM Reset Value L l Reset Integrator Xl a p ex D expt Description p WE Model Root finalTime FloatIeee Simulation 1 gi Labels currentTime FloatIeee Current si Task Into modelStepSize Floatleee64 Fixed step simState Int32 Simulation errorNumber UInt32 Err
89. saase ene uaas ced et ecereiest aa sande ence iret oosfies oin bx inten dinsr ie 67 i PO a etn eat T aaa eine T E nn situa cede eo ES opi cR 70 EXPERIMENT 7 PERMANENT MAGNET AC PMAC MOTOR eee 71 PLAIN PRODUCTION NCC PPP 7 A2 THEORY SPACE VECTORS DO WENDEINGIS 5525652 nbn dans cheer oneness pud I eo eS R YEN Pea wellness 7 7 3 OBSERVING THE BACK EMP OF THE PMAC MOTOR eere nine ret RR SERRE DN NE EISE Ca e teu ROVS 12 TACURRENT CONTROLLED PMAC MACHINE d it encedUEo ND Ie EPA EU RES EDI n Rd ebaR abiur t duis 75 7 5 RUN THE MOTOR WITH SPEED CONTROL OPTIONAL 00 cee ccc cece mI HI eme enne 18 TONERS REPORT ciraire stad oe tae idu edite tu uv td eeu D LEUTE Eco 80 727 REFERENCE pr 81 EXPERIMENT 8 DETERMINATION OF INDUCTION MACHINE PARAMETERS 82 S MIN TPRODUC TION csdocbert6nage tatus bentme ds dette aca tale dm ue tenet b p e en Lau dti teted semen acamuetoncuea 82 S DETERMINE R Nhe gant tes coute duni E sedan atta bed ertet Dude meinte bruta 83 Go DETERMINE Da s tesis a Meu dae meli des Eua Santee data ALODIUM M aces 83 STRATED SR ora scence sec Ons E aa oe ade Dc a Eod Ca MATS Uu oe Sich Meena etna enemas 86 oA DETERMINE Ei be R eater hai hse eae hy spa tee lactate te er ne nec a en win SU ea tap murine ty Mio EA 86 GO SAD REPORT cess ace ingenio eee ase lee ae LAM LM M LM MIR LIA O a oi een E ant MU CAD nice 88 THREE PHASE INDUCTION MOTOR condes sacatctntedteciessswadacaiaiionawe demu I aou P
90. se burns Do not wear them near an energized circuit Learn CPR and keep up to date You can save a life When working with energized circuits while operating switches adjusting controls adjusting test equipment use only one hand while keeping the rest of your body away from conducting surfaces 1 4 Power Electronics Drives Board familiarization The electric machine drives board which we use in the Electric Drives Laboratory has been designed to enable us to perform a variety of experiments on AC DC machines The main features of the board are Two completely independent 3 phase PWM inverters for complete simultaneous control of two machines 42 V dc bus voltage to reduce electrical hazards Digital PWM input channels for real time digital control 101 e Complete digital analog interface with dSPACE board The basic block diagram of drives board is shown in Fig 1 and the actual drives board is shown in Fig 2 Please note that various components on this board are indicated in Table 1 1 4 1 Description of Power Electronic Drive Board The board of Fig 2 1s shown with some additional labels in Fig 3 The two independent three phase PWM voltage sources labeled phases Al Bl Cl and phases A2 B2 C2 in Fig 1 are obtained from a constant DC voltage source as shown in Circuit in Fig 1 Hence two machines can be controlled independently for independent control variables at the same time A single phase motor needs
91. t B However during simulations B can be considered zero or its value can be obtained from experiment 4 and the model will be similar to the one described by equations 1 and 2 Create a subsystem by selecting components shown in Fig 5 1 and name it as DC 5 Machine The simulation block of the DC motor parameters is shown in Fig 5 2 a Simulink Model 46H PA Alaa oag 46H SAH Ate GAR a I PAH ABE SAR v Time offset 0 Time offset 0 Time offset 0 b Waveform for Om c Waveform for Ia d Waveform for Tem Figure 5 1 Simulink model of DC motor and waveforms for Wm Ia and Tem gt wm 20 B va Scope 2 Va la 5 1 0 1 gt TL Tem eee Load Torque qu DC Motor gt Scope 3 Figure 5 2 Simulation block of DC Motor Parameters 32 e Now enter the values of DC motor parameters which were evaluated in experiment 3 and 4 in file dc motor parameters m Ia initial wm initial are the initial values for the integrator To observe the zero initial condition response set these values to zero Run this file Make sure your units are all consistent e Run the simulation with default configuration parameters for the following two cases Compare the observed values with calculated values Save the plots and include them in your report a Va 20V Load Torque 0 3 Nm b Va 20V Load Torque 0 Nm 5 3 Cont
92. t high power or high voltage e Use rubber floor mats if available to insulate yourself from ground when working in the Lab e Be sure about the locations of fire extinguishers and first aid kits in lab e A switch should be included in each supply circuit so that when opened these switches will de energize the entire setup Place these switches so that you can reach them quickly in case of emergency and without reaching across hot or high voltage components 1 3 2 Precautions to be taken when preparing a circuit e Use only isolated power sources either isolated power supplies or AC power through isolation power transformers This helps using a grounded oscilloscope and reduces the possibility of risk of completing a circuit through your body or destroying the test equipment 99 1 3 3 Precautions to be taken before powering the circuit Check for all the connections of the circuit and scope connections before powering the circuit to avoid shorting or any ground looping that may lead to electrical shocks or damage of equipment Check any connections for shorting two different voltage levels Check 1f you have connected load at the output Double check your wiring and circuit connections It 1s a good idea to use a point to point wiring diagram to review when making these checks 1 3 4 Precautions while switching ON the circuit Apply low voltages or low power to check proper functionality of circuits Once functiona
93. ta da or theta da the d axis is aligned along the rotor axis Before running the PMAC motor the rotor is initialized to a known 75 position done by checking lock To initialize the motor a small voltage of 1V is applied between phases Al and B1 The dc currents in phase a and phase b produce mmf vectors as marked in Fig 7 5 b This causes the rotor thus the d axis to align 2 6 away from the physical a axis When lock is unchecked the a and b phase currents are sensed and the c phase current is calculated from it an abc dq transformation is applied eq 3 to obtain 1 4 and 1 4 The error between the actual currents and the ref currents are passed through a PI controller that dictates the necessary phase voltages The initial voltage can now be removed and a reference current that is aligned with the q axis 154 is applied to the motor to generate the maximum torque b axis Hs Ls AJNINr po uw N C Fa j p gt a axis 0 Va kew VY d axis c axis P Fb a Per phase equivalent circuit of PMAC b Rotor Locking Position Machine Figure 7 5 Current Controlled PMAC Machine dSPACE I O Board ENCODER To INC 1 Figure 7 6 Connections for Section 7 4 and 7 5 76 7 4 2 Real time implementation of current controlled motor e Make the connections as shown in Fig 7 6 e Open the file PMAC current mdl Obtain the values for Kp 1 and Ki 1 from Table 2 of this experiment Enter t
94. the initial slope of the current 7 pt 3 Section 3 5 2 5 points a Plot the voltage vs speed characteristics of the DC motor 7 pt b Comment on the graph 0 5 pt c Using the value of Ra kg and measured Ia calculate speed and plot the measured speed and calculated speed on the same graph 7 pt Report 1 point 37 Experiment 4 Characterization of DC Motor Part 2 4 1 Introduction In the previous experiment the electrical parameters Ra La and kg of the DC motor were determined In this experiment the mechanical characteristics B and J will be determined The torque speed characteristics will be verified 4 2 Open loop control of DC motor with load The Simulink model used in Experiment 3 will be used in this experiment e Create a new folder Expt 4 e Start Matlab and change the directory path to Expt 4 e Open the Simulink model used in the last experiment or download the file no_load mdl Note the speed output is in radians sec To this model appropriate blocks for controlling the active load a DC generator whose electromagnetic torque will be varied need to be added 4 2 1 Adding a DC load LOAD to the DC motor MOTOR To determine the DC motor steady state characteristics a second DC motor will be axially coupled to the motor under test MUT The second motor will be open loop voltage controlled similar to the MUT e The terminals of the load DC motor should be connected to PHASE A2
95. the line and the y intercept Table 2 No load torque speed characteristics to calculate B and T fiction Vagi O Speed rad sec Current A o HN Use the values obtained from Table 2 in experiment 3 and calculate the torque 4 4 Determination of Inertia In this section the moment of inertia J kg m will be determined The setup consists of two DC motors axially coupled and supplied from two converters One motor is current controlled 44 such that it will act as an active load This motor will be named as LOAD The second motor MUT is open loop voltage controlled This motor will be named as MOTOR do Te Ty Lefton BaotJ dt 4 The motor is brought to a no load steady state E o speed o by disconnecting the load Tj 2 0 At this point t O T Thiction Boy where Ty k4I o L o MOTOR currentat steady state no load speed 5 To make electrical torque Te equal to zero in the mechanical dynamics equation 4 a complete shutdown of the motor supply is required At t 2 0 the whole system is shutdown This implies that the electromagnetic torques in the MOTOR Te becomes zero The dynamic equation will be do 0 dos Bo J 6 dt At t 2 0 i e just after shutting down the system the equation 6 can be written as do Igicion BO e 7 dt 9 Thus J E Tieten Bo OR kyl o 8 Fhe
96. them as shown in Fig 2 3 e Inthe Matlab prompt type fsw 10000 Vd 42 e Set the simulation parameters as in section 2 3 1 and save the model e Runthe simulation and save the waveform for the switching function Fig 2 3 2 3 3 Two pole Converter Model Equations 7 and 8 describe the control voltages of the two poles A amp B depending on the desired output voltagev v These equations will be implemented in Simulink Fig 2 4 Also the switching power poles will be modeled using a Switch The Relay blocks provide the switching functions for the poles q and q Depending on the value of the switching function the Switch outputs the pole voltage as follows Forq 1 switch output Pole A v V Forq 0 switch output Pole A v 0 Create the Simulink model as shown in Fig 2 5 The Switch block can be found in Simulink gt Signal Routing Change the threshold voltage of the switch to 0 5 Fig 2 4 or to any number greater than 0 but less than 1 Can you tell why i 8 Oil PM m uu Function Block Parameters Switch ning Switch T Pass through input 1 when input 2 satisfies the selected criterion otherwise pass through input 3 The inputs are numbered top to bottom or left to right The input 1 pass through criteria are input 2 greater than or equal greater than or not equal ta the threshold The first and third input ports are data ports
97. to be at 10 higher than 900 rpm and save the voltage and current waveforms to supersync mat Now change Wref to be at 10 lower than 900 rpm Save the voltage and current waveforms as subsync mat 92 e Set Fref Hz back to zero and lower the value of Wref back to zero Stop the experiment in edit mode Close dSpace ControlDesk e The power supplied by the induction motor can be calculated using lines 43 87 file im torquespeed m 9 4 Speed Control of Three Phase Induction Motor 9 4 1 Without Speed Feedback The control of a three phase induction motor without direct speed measurement is described in 2 In this experiment the current limiter circuit is ignored and the applied voltage is V f controlled The block diagram for this control is given in Fig 9 3 The dc current I4 1s calculated on an average sense using 3 The power supplied to the induction motor is Pm 4 Neglecting losses the supplied power is related to Tem by 5 In the linear region of operation Tem 1s proportional to Wslip 6 The required oi to support this torque can be calculated using 7 By 8 the frequency of voltages Wsync that are applied to the motor can be calculated The voltage magnitude is calculated such that V f 1s a constant Voltage boost 1s 1gnored Note This control strategy works only when the motor is already running hence the motor is started and stopped using simple V f control Ia 14d ipdp RE i d 3
98. u bed 89 OL TIN SEO B WC TION Tc rA IS mney ne 89 22 LORQUE SPEED CHARACTER TICS rici e Dese eden e posu EE LECCE ener CIN mU TEE 89 9 3 GENERATING AND MOTORING MODE OF INDUCTION MOTOR sem 92 9 4 SPEED CONTROL OF THREE PHASE INDUCTION MOTOR sss II sad 90 IGA DB REPOR dE 97 TORET ERENCE NE 97 APPENDIX A SAFETY PRECAUTIONS AND POWER ELECTRONICS DRIVES BOARD CP1104 I O BOARD DS1104 CONTROL BOARD AND MOTOR COUPLING UNTI FAMILIARIZA TION 5 uci ERI ERVEUPT UN DAS na a ea taai eo 98 1 1 WHY IS SAFETY IMPORTANT aan an a aaa 98 1 2 POTENTIAL PROBLEMS PRESENTED BY POWER ELECTRONIC CIRCUITS eme 98 1 3 SAFETY PRECAUTIONS TO MINIMIZE THESE HAZARDS e Renee mes 99 1 4 POWER ELECTRONICS DRIVES BOARD FAMILIARIZATION e eee 101 1 5 DS1104 R amp D CONTROLLER BOARD AND CP1104 I O BOARD R eee 108 1 6 MATLAB SIMULINK AND CONTROL DESK PROGRAMMING DS1104 AND CONTROL IN REAL EIMB ugs M CR MM M D MAN ELM II UE UU EAE 109 1 7 MOTOR COUPLING SYSTEM eee rrr rrrrrrr herren rere rere rere rere rere erret nan 109 Experiment 1 Introduction to the DSP based Electric Drives System 1 1 Introduction There are four major components of the DSP based electric drives system which will be used to perform all the experiments in this course They are as follows 1 Motor coupling system 2 Power Electronics Drive Board 3 DSP based DS1104 R amp D controller card and CP 1104 I O board and 4 MATLA
99. ual Out1 0 152 motor speed Out1 PI Current reset 1 vc EX e eo 5 9 16 5 ka D 4 pi el JA E ds E e o oe Figure 6 9 dSpace ControlDesk speed controlled DC motor with torque controlled load 69 6 5 Lab Report 70 points 1 Section 6 1 Save the waveform for the actual speed and measured speed and label the quadrant of operation 2 points 2 Section 6 2 e Part a Attach the waveform from dSpaceControlDesk when the torque step is applied to the motor 7 points e Answer Part a 3 to 6 including 3 and 6 1 points e Part b Attach the waveform from dSpaceControlDesk when the torque step is applied to the motor J points e Answer Part b 3 to 6 including 3 and 6 7 points 3 Section 6 3 e Attach the waveform for 6 3 5 and 8 2 points e Answer 6 395 to 1 1 including 5 and 11 2 points 4 Bonus Keep the speed of the motor constant at 150 rad sec Give a sinusoidal disturbance use frequency of 1Hz of 0 05 Nm in load torque over a constant value of 0 15Nm Observe how the control system responds to the disturbance Attach the waveform of the reference torque actual torque developed by the motor and the speed of the motor 3 points 70 Experiment 7 Permanent Magnet AC PMAC Motor 7 1 Introduction In this experiment the vector control of a three phase Permanent Magnet AC PMAC motor will be studied Real time Simulink and layout files are given to
100. y The desired voltage vaN is set by a Constant block with value one and can be varied with a Slider gain from 0 to the maximum DC bus voltage Va Va 42V in the model The control voltage is generated by dividing van by Va This is done by using a Gain block of value 1 V at the output of the Slider gain Comparison of the triangular signal and the control voltage is done using a Relay block The triangular signal is subtracted from the control voltage The Relay block output is then set to 1 when the difference is positive and 0 when the difference is negative To create the model follow the steps below e Open Simulink and create a new model e Copy and paste the model of triangular waveform generator from section 2 3 1 Fig 2 2 16 Add these parts to the model o Constant block from Simulink Sources o Slider Gain from Simulink Math Operations o Gain from Simulink Math Operations o Sum from Simulink Math Operations o Relay from Simulink Discontinuities Now change the properties of these blocks as follows o Change the Slider Gain limits as shown in Fig 2 3 o Change the value of Gain to 1 Vq V4 will be set to 42V from the command prompt later o Change Sum block signs to 4 Repeating Sequence Scope O 10 x amp B o9poemmuo Time affzet OU Figure 2 3 Switching Function generation for single pole converter 17 e Rename the blocks and connect

Electric Drives Lab Manual - Electrical and Computer Engineering

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