BITS-PILANI, K.K BIRLA GOA CAMPUS Laboratory Manual EEE/INSTR F342 Power Electronics Semester II 2016-2017 Team of Instructors Femi R, Dr. Narayan Manjarekar, Dr. Gautam Bacher, Dr. Shashidhara Mecha Kotian, Metilda Sagaya Mary N. J., Athokpam Bharatbushan Singh, Prakash Lamani, Ishwar R Rathod List of experiments 1. Preparatory Laboratory Experiment- Introduction to Isolated and high voltage measurement: Uncontrolled bridge rectifier and controlled half bridge Rectifier 2. Study of Step down converter 3. Study of Boost converter 4. Study of Forward converter 5. Study of Single Phase Semi-controlled and fully Controlled Rectifier. 6. Study of Three Phase Semi controlled rectifier. 7. Study of Single phase AC/AC converters. EEE/INSRT F342 Power Electronics Page 2 SOME PRECAUTIONS AND SAFETY MEASURES 1. All students should wear full shoes with rubber sole. Loose clothes or loose hair is to be avoided. 2. Do not touch any live terminals or wires. For changing any connections you must switch-off the supply. 3. Beware of the dynamic machinery and consciously keep a distance. 4. Before switching ON the supplies, get your circuit connections approved by the instructors. 5. Be alert and always power OFF if you want to make any change in connections. 6. Make sure you switch OFF the measuring instruments once you are done with the experiment. INSTRUCTIONS REGARDING OPERATION OF LAB 1. Thoroughly read the instruction set and come prepared to conduct the experiment. 2. Before starting the experiment: (a) Come with m a n u a l w i t h the relevant e x p e r i m e n t . (b) Note down the safe operating limits of the converter. Never exceed the ratings specified. (c) Write down the instruments and accessories that you need to conduct the experiment (along with their ranges, rating etc.). 3. Connect the wires, multimeters, scope etc. as per the circuit diagram. Get the circuit connections verified by the instructor. 4. Start/switch-on the set (instructions are given in the instruction set). 5. Carry out the experiment as per the steps given in instruction set. Record the readings/ note the waveforms. 6. All computations are to be carried out in the laboratory itself. Attach g r a p h s h e e t a n d a ny additional sheet you need. 7. You are required to submit the completed lab report of the experiment of the previous turn when you enter the laboratory. EEE/INSRT F342 Power Electronics Page 3 1Ω. If not. This information may be used as setting for the Digital storage oscilloscope to make sure that the measurement displayed is scaled appropriately. it is suggested to use a probe/ isolation section of 100x. 2. 5. take care of the scaling in your calculations. (e. 4. In case you are not using the setup option in DSO. you may open circuit an inductor or short circuit a capacitor inadvertently which may lead to serious damage of equipments and may result in injuries to the user(s). For example. EEE/INSRT F342 Power Electronics Page 4 . Individual measurements has to be done in isolation in Power electronic systems as the reference (ground ) for most of the measurements will be at different potentials.1x. 3.g:. Take note of the attenuation factor in case of probes used and/or if you are using power isolation section. Take the appropriate probe rating/ attenuation to make sure that you operate safely and obtain accurate results. Failure to use proper isolation may lead to damage to the equipment and also may result in injury to the user(s). please use the Power isolation section provided in the kit. 10x . then the scaling factor is 100mV/ A or 10A/V. If sensing resistances are used for measuring currents. For grid voltage levels. if Rsense=0. 100x. Make sure that the oscilloscope that is used for the measurement has isolated channels for measurement. For higher voltages (greater than 100V). 10mV/A) to get the scaling factor of the measured value. 100x must be used. Tips for safety and accuracy for measurements in Power Electronic Laboratory 1. Always make sure that you switch OFF the power supply for making any change in connection or even for changing a measurement point. please use the appropriate scaling factor to get the reading. If not. To study the measurement of firing angle and functioning of a single phase half wave controlled (single thyristor switch) rectifier. Voltage probes and clamp-on current probes (Tektronix A621). Attenuation for the power isolation unit should be kept at 100x for voltages higher than 100V. 2. PREPARATORY LABORATORY EXPERIMENT INTRODUCTION TO ISOLATED AND HIGH VOLTAGE MEASUREMENT Name ID No. power isolation section (Powerscope) provided on the set- up is to be used. c. Sec. b. Patch Cords & Operating manual for HV lab 2700. Make sure that Ammeters are connected in series with and Voltmeters are connected parallel across the load respectively.No Batch No. Marks obtained Date Instructor’s signature OBJECTIVES a. Digital Multimeter 4. PRECAUTIONS: Make sure that for all the measurements above 50V. Make sure use appropriate range in case of voltmeter/ammeter are within the proper range. 3. Verify the type (AC/DC) before connection. 1. Clamp-on Current probe is to be directly connected to CRO. To Study the isolated high voltage measurement and current measurement using CRO/DSO and multimeter for a single phase uncontrolled bridge rectifier. To study the firing pulse generation circuit. Cathod Ray Oscilloscope/Digital Storage Oscilloscope. EEE/INSRT F342 Power Electronics Page 5 . ST2700 High Voltage Power Electronics Lab 5. EQUIPMENTS NEEDED 1. 7. Connect the DC Voltmeter. Now remove the output voltage from channel 1. 12. Connect one terminal of load from Load Assembly to common cathode terminal of diode D1 and diode D3 and other terminal of load is connected to common anode terminal of diodes D4 and D3. 9. 6. Connect Line Terminal (L) from single phase supply to anode of diode D1 or cathode of diode D4 and connect neutral (N) terminal from single phase supply to anode of diode D2 or cathode of diode D3. 3. Switch on MCB of Single Phase Supply and observe the voltage waveforms on the oscilloscope. Make Connections according to Figure (a). 5. Switch ATT of A is at ‘x 100’ position and switch of coupling of A should be at ‘DC’ position. 8. 11. from the power circuit to the input of the power scope using patch chords. Connect the voltages to be measured (voltage across the load and voltage across diode D1). Connect input of Power Scope A to the load. Connect BNC to BNC cable at CH2 of oscilloscope to output of Power Scope B.1: Single Phase Bridge Uncontrolled Rectifier I. EEE/INSRT F342 Power Electronics Page 6 . Connect the Lamp at the Load. 2. Ammeter at the load. Connect BNC to BNC cable at CH1 of oscilloscope to output of Power Scope A. 4. Similarly. PROCEDURE FOR STUDYING THE ISOLATED HIGH VOLTAGE MEASUREMENT AND CURRENT FOR A SINGLE PHASE BRIDGE UNCONTROLLED RECTIFIER: Make sure that there is no connection on the board initially. 1. and connect the clamp-on current probe (directly) to channel 1 of the oscilloscope and measure the diode voltage (VD1) and diode current (ID1) simultaneously. 10. Verify the connections before turning the MCB of single phase supply ON. CONNECTION DIAGRAM: Figure 1. Take the readings and tabulate in Observation Table (a).1: Vs= Specification of a single lamp = V. Repeat the measurements and observe the waveforms of load voltage (VL) vs load current (IL). input voltage (VS) vs input current (IS) using oscilloscope. Also make the DC voltage measurements using multimeter. Voltage (Vo) Voltage (Vo) Current (Io (DC)) (IS (RMS)) EEE/INSRT F342 Power Electronics Page 7 . W Resistance of a single lamp = Ω RLOAD= Ω Measured Output Calculated Output Measured Output Input current. 14. 13. Model Waveforms OBSERVATION TABLE 1. 5. Connect BNC to Test Probe cable at CH1 and CH2 of oscilloscope. Observe the output of ramp generator at point 3 with respect to in CH1. PROCEDURE FOR STUDYING THE ISOLATED MEASUREMENT AND RAMP FIRING SCHEME FOR SINGLE PHASE RECTIFIERS: Make sure that there is no connection on the Work Bench initially. Vary the firing angle control potentiometer and observe the pulse width variation in pulse 1. Connect +12V. Connect patch cord point 4 to point 6 and connect patch cord point 5 to point 7.2: Ramp comparator firing circuit II. Observe the output of ramp comparator and pulse generator at point 4 with respect to ground in CH1 and output at point to with reference to ground at point 5 in CH2. Switch on the oscilloscope. Switch on the three phase MCB of back panel. Observe the phase shift between the two signals. 8. Figure 1. the signals may be connected without isolation. EEE/INSRT F342 Power Electronics Page 8 . 2. Note that. 7. 4. Vary the firing angle control potentiometer and observe the variation in Vref. 1. +5V and ground (GND) and connect 18-0-18 at ramp comparator firing circuit from single phase low voltage power supply. 3. Observe the reference voltage at point Vref with respect to ground. Observe the output of the zero crossing detector 1 with respect to ground in CH1 and the output of zero crossing detector 2 with respect to ground n CH2. 6. Red. Yellow and Blue indicator glow at front panel. and G3 with respect to K3 using the isolated channel DSO (TPS 2014B). Connect gate pulse G1 at gate (G) of SCR1 and connect K1 at cathode of SCR1 from ramp comparator firing circuit. Switch on the three phase MCB of back panel. Observe the gate pulse at G1 with respect to K1 (OR G2 with respect to K2) vary the firing angle control potentiometer and observe the variation in gate pulse in CH1. Connect the Lamp at the Load. 10. Use SCR1 from SCR Assembly and to construct single phase half wave controlled rectifier configuration. Verify the connections before switch on the MCB of single phase supply. 4. Connect the one terminal of load from Load Assembly to cathode terminal of SCR1 and other terminal of load is connect to neutral terminal from single phase supply.3: Single phase half wave controlled rectifier. Connect input of Power Scope A to the load. Do not connect two signals simultaneously. 7. 6. Connect Line Terminal (L) from single phase supply to anode of SCR1. 9. Switch ATT of A is at ‘x 100’ position and switch of coupling of A should be at ‘DC’ position. Connect BNC to BNC cable at CH1 of oscilloscope to output of Power Scope A. III. ------------------------------------------------------------------------------------------------------------------------------------ Figure 1. 2. Note that you may connect the two outputs simultaneously to two/four channels of the DSO. 11. Yellow and Blue indicator glow at front panel. EEE/INSRT F342 Power Electronics Page 9 . 9. 3. 10. Observe the input voltage. Connect +12V. +5V and ground (GND) and connect 18-0-18 at ramp comparator firing circuit from single phase low voltage power supply. Red. PROCEDURE FOR STUDYING THE ISOLATED HIGH VOLTAGE MEASUREMENT AND CURRENT FOR A SINGLE PHASE BRIDGE UNCONTROLLED RECTIFIER: Make sure that there is no connection on the Work Bench initially. Vary the firing angle control potentiometer and observe the variation in gate pulse. gate pulse at G1 with respect to K1. 8. 1. 5. Supply Current (IS). 2. Supply Current (IS). 13. 14. Draw the graphs of Line Voltage (VS). EEE/INSRT F342 Power Electronics Page 10 . Diode voltage (VD1) and Diode Current (ID1) for Single Phase Bridge Uncontrolled Rectifier. Diode voltage (VD1) and Diode Current (ID1) for Single Phase half wave controlled rectifier. Output Voltage (Vo). Voltage (Vo) Voltage (Vo) Current (Io (DC)) (IS (RMS)) GRAPHS 1. MODEL WAVEFORM Measured Output Calculated Output Measured Output Input current. Switch on MCB of Single Phase Supply and observe the output waveform of load terminals on the oscilloscope. 12. Output Voltage (Vo). Connect the DC Voltmeter at the load and measure the output DC voltage across the load. Observe the voltage waveform at the load. Draw the graphs of Line Voltage (VS). SPECIFICATION FOR THE ST2700 HIGH VOLTAGE POWER ELECTRONICS LAB EEE/INSRT F342 Power Electronics Page 11 . Digital Multimeter 3. Make sure that there is no connection on the board initially. EXPERIMENT No. To Study the PWM generation Circuit for step down converter.1: PWM generation circuit PROCEDURE FOR STUDYING THE PWM CIRCUIT. ST2724 Step Down Chopper and power supply. Similarly. 2 STUDY OF STEP DOWN CONVERTER Name ID No. EQUIPMENTS NEEDED 1.1. Oscilloscope 2. 3. Marks obtained Date Instructor’s signature OBJECTIVES a. 5. BNC to Test Probe 4. 2. Rotate the frequency control potentiometer gradually in the anticlockwise direction.No Batch No. Patch Cords & Operating manual CONNECTION DIAGRAM: Figure 2. Sec. EEE/INSRT F342 Power Electronics Page 12 . Make the connections according to Figure 1. rotate the PWM control potentiometer also in the anticlockwise direction. b. Study the performance of the down converter for various loads with (i) MOSFET (ii) IGBT and (ii) Thyristor as the switch. 1. 1. Record the maximum & minimum frequency and pulse width in the observation table 1. Connect the load (R load without L. 6. Set the frequency control potentiometer to some value. 3. 6. EEE/INSRT F342 Power Electronics Page 13 . OBSERVATION TABLE 2. Make sure that there is no connection on the board initially. Connect the PWM pulse from the PWM circuit to the Gate (G) of the MOSFET. 5. Observe the triangular wave output at Test Points TP3 with respect to the ground. 7. Observe the PWM signal at PWM pulse with respect to ground. 5. Set the frequency of PWM pulse by frequency control potentiometer at 4KHz. 10. RL load without L and motor load without L) at its indicated position. 9.2 : Step Down converter PROCEDURE FOR STUDYING THE DOWN CONVERTER WITH VARIOUS LOADS. Switch off the power supply. Vary the PWM control potentiometer & observe the change in voltage either on the multimeter or on the oscilloscope by putting it into the DC Mode. then vary the PWM control potentiometer & observe the PWM pulse. 12. Connect the MOSFET at chopper section in step down chopper configuration. 2. Observe the reference voltage (Vref) at Test Points TP4 with respect to ground. 1. 4. 4. Switch ‘On’ the power supply. Vary the frequency control potentiometer and observe the variation in frequency. Connect the power supply +24V & ground at their indicated positions.1: Minimum Maximum Minimum Pulse Maximum Pulse Frequency (Hz) Frequency (Hz) Width (%) Width (%) Figure 1. 8. 11. 7. Switch on the power supply. Connect the Gnd from the PWM circuit to the Source (S) of the MOSFET. Observe the square wave output between Test Points TP1 with respect to TP2. 8. 11. Verify the output DC voltage with the theoretical value. Switch ‘Off’ the power supply. Disconnect PWM pulse and input voltage from the power circuit. Repeat the experiment for different switches (IGBT and thyristor) at different duty ratios. Connect the multimeter in DC mode. Vary the PWM control potentiometer and observe the output voltage across the load. Frequency PWM Output voltage across Device Output voltage across No. switch and diode. 12. 9.2 R. OBSERVATION TABLE 2. Connect the oscilloscope and vary the PWM control potentiometer & observe switch voltage.Load Measured Measured Theoretical Measured S. (Hz) (%) Voltage the device Voltage (V) the diode (V) (V) (V) 1 MOSFET 4kHz 40% 2 MOSFET 4kHz 80% 3 MOSFET 500Hz 40% 4 MOSFET 500Hz 80% 5 IGBT 4kHz 40% 6 IGBT 4kHz 80% 7 IGBT 500Hz 40% 8 IGBT 500Hz 80% EEE/INSRT F342 Power Electronics Page 14 . 10. diode voltage and output voltage waveform across the load. Set the frequency of PWM pulse by frequency control potentiometer at 500Hz & repeat the experiment. Switch ‘On’ the power supply. Frequency PWM Output voltage across Device Output voltage across No. (Hz) (%) Voltage the device Voltage (V) the diode (V) (V) (V) 1 MOSFET 4kHz 40% 2 MOSFET 4kHz 80% 3 MOSFET 500Hz 40% 4 MOSFET 500Hz 80% 5 IGBT 4kHz 40% 6 IGBT 4kHz 80% 7 IGBT 500Hz 40% 8 IGBT 500Hz 80% EEE/INSRT F342 Power Electronics Page 15 . Frequency PWM Output voltage across Device Output voltage across No.Load Measured Measured Theoretical Measured S. RL. (Hz) (%) Voltage the device Voltage (V) the diode (V) (V) (V) 1 MOSFET 4kHz 40% 2 MOSFET 4kHz 80% 3 MOSFET 500Hz 40% 4 MOSFET 500Hz 80% 5 IGBT 4kHz 40% 6 IGBT 4kHz 80% 7 IGBT 500Hz 40% 8 IGBT 500Hz 80% Motor Load Measured Measured Theoretical Measured S. GRAPHS 1. Draw the graphs of PWM output.8 for motor load with filter inductor when MOSFET is used as a switch.4 for motor load with filter inductor when MOSFET is used as a switch. 3. Draw the graphs of PWM output.4 for RL load with filter inductor when MOSFET is used as a switch. output voltage and diode voltage at switching frequency 4 k Hz for duty ratios 0. 4.8 for RL load with filter inductor when MOSFET is used as a switch. 2. output voltage and diode voltage at switching frequency 500Hz for duty ratios 0. Draw the graphs of PWM output. EEE/INSRT F342 Power Electronics Page 16 . Draw the graphs of PWM output. output voltage and diode voltage at switching frequency 4 k Hz for duty ratios 0. output voltage and diode voltage at switching frequency 500Hz for duty ratios 0. 5A SCR Assembly : SCR TYN 616. 24V. 600 V. 50 Hz EEE/INSRT F342 Power Electronics Page 17 .5A. 600V. 10mH DC Geared Motor : 24V/ 0. 100V. 1A Power Supply : 230 V 10%. 0. 10A Transistor Assembly : Transistor TIP122. 100 RPM Interconnections : 2 mm sockets MOSFET Assembly : MOSFET IRFZ44N. 16A Fuse : 1A DC Power Supply (SMPS) : 12V. Specification for the ST2724 Step down converter On Board PWM Circuit : Triangular Comparator Circuit Frequency Variation : 27 Hz to 5 KHz (approximately) PWM Variation : 0-90% Inductor : 68 mH R load : 1kΩ RL Load : 1kΩ. 49A IGBT Assembly : IGBT G4BC20S.5A. 55V. C and load EQUIPMENTS NEEDED 1.No Batch No. 3 STUDY OF BOOST CONVERTER Name ID No. Sec. Connect the Power supply (SMPS) to Techbook Scientech 2727. EXPERIMENT No. Marks obtained Date Instructor’s signature OBJECTIVES a. 5. Patch Cords & Operating manual CIRCUIT DIAGRAM: Figure 3. BNC to Test Probe 4. Techbook Scientech 2727 and power supply. Study the performance of the Boost converter for different values of L. Oscilloscope 2. EEE/INSRT F342 Power Electronics Page 18 . Switch on the instrument. 2.1 Power circuit for Boost converter PROCEDURE FOR STUDYING THE PWM CIRCUIT. b. 1. To Study the PWM generation Circuit for Boost converter. Make sure that there is no connection on the board initially. Digital Multimeter 3. Switch ON the Power supply unit. 6. 1. 4. Switch OFF the Power supply unit. 8. 2. Remove the test probes from ST 2729. 8. Observe the output of optical isolation block at TP2 with respect to ISO_GND on oscilloscope. output capacitor ripple voltage. Vary the PWM control potentiometer at different pulse width. 12. 11. Connect the multimeter in DC mode and vary the PWM control potentiometer and observe the output voltage across the load. Switch on the instrument. 4. 7. Vary the Duty Cycle control potentiometer to observe the duty cycle variation on the oscilloscope. Observe the variable DC voltage across the load. 6.1: Minimum Maximum Minimum Pulse Maximum Pulse Frequency Frequency Width Width (Hz) (Hz) (%) (%) PROCEDURE FOR STUDYING THE BOOST CONVERTER Make sure that there is no connection on the board initially. Set the PWM duty cycle at minimum by varying Duty cycle control potentiometer. Connect one end of inductor L1 to the diode D1 & the other end of inductor L1 to positive terminal of capacitor C1. 5. 9. measure Vo in ac coupling. 10. and capacitor current. 7. OBSERVATION TABLE 3. Switch OFF the Power supply Unit. (For output ripple voltage. Observe the Gate pulse at TP3 with respect Vs. Observe the output of PWM Generation block at TP1 with respect to GND on oscilloscope. switch and diode. Set the chopping frequency at 20 KHz by the frequency potentiometer. 13. Connect the oscilloscope and vary the PWM control potentiometer & observe the waveforms of inductor current. Connect the one end of the RL1 to the one end of the load terminal & other terminal of the RL1 to the other end of the load. 3. diode current. Connect +24V and ISO_GND to the boost configuration. Verify the output DC voltage with the theoretical value.) EEE/INSRT F342 Power Electronics Page 19 . 3. Connect the GATE pulse to the gate of the T1 (IGBT). Vary the frequency control potentiometer to observe frequency variation on the oscilloscope. 5. 15.2 Load = R1//R2 Ω Measured Theoretica Measured Measured Inductor S. Disconnect all the connections from the board. C and load. Capacitor Output l Output voltage across voltage value PWM (%) No. 14. capacitor current and voltage across the switch for duty ratio of 0. diode current. EEE/INSRT F342 Power Electronics Page 20 . inductor current. Switch ‘Off’ the power supply. Repeat the experiment for different values of L. 2. Draw the graphs of PWM output. OBSERVATION TABLE 3. capacitor current and voltage across the switch for duty ratio of 0. inductor current.2 for the values of L1+L2 and C1 for Boost converter. Draw the graphs of PWM output.33 for the values of L1+L2 and C1 for Boost converter. (µF) Voltage Voltage the switch across the (µH) (V) (V) (V) diode (V) 1 L1 C1 20% 2 L1 C1 33% 3 L1+L2 C1 20% 4 L1+L2 C1 33% GRAPHS 1. 16. diode current. 12V@ 500mA. +5V@250mA SMPS : +/- 15V@1A SMPS : +24 V@1A for DC rail Input DC Voltage : 24V/1A PWM Frequency Variation : 1 KHz to 22 KHz Duty Cycle Variation : 10% to 45% Power Isolation Section : Single channel. 50/60Hz Weight : 1. Specification for the ST2727 Boost converter SMPS : +/.5Kg (approximately) Operating Conditions : 0-400 C. +5V@250mA SMPS : +/.260V AC. 10x Power device : IGBT TOSHIBA 20JT101 Diode : UF4007 MOSFET/ IGBT Driver : MC33153 Rsense : 0. The maximum output power should not exceed 20W.5mH 404uH User 1000uF/63V 470uF/63V 220uF/63V 75Ω/ 25W 75Ω/ 25W Please use external load for observing output power more than 15W. EEE/INSRT F342 Power Electronics Page 21 .12V@ 500mA.1Ω Turn off Snubber : 100E 1W & 0. 85% RH L1 L2 L3 C1 C2 C3 RL1 RL2 1.1µF 250V Dimensions (mm) : W 326 x D 252 x H 52 Power Supply : 110V . EQUIPMENTS NEEDED 1. Switch on the instrument. To Study the PWM generation Circuit for forward converter. Study the performance of the forward converter for various loads.1 Power circuit for a practical forward converter PROCEDURE FOR STUDYING THE PWM CIRCUIT Make sure that there is no connection on the board initially. Observe the output of PWM Generation section with respect to GND on oscilloscope. Digital Multimeter 3. Patch Cords & Operating manual. 1. BNC to Test Probe 4. Vary the duty cycle control potentiometer to observe duty cycle variation on oscilloscope. 5. 2. 3. Sec. Scientech 2730 forward converter and power supply. Oscilloscope 2. Figure 4. 4 STUDY OF FORWARD CONVERTER Name ID No.No Batch No. EXPERIMENT No. EEE/INSRT F342 Power Electronics Page 22 . Marks obtained Date Instructor’s signature OBJECTIVES a. b. Connect the multimeter in DC mode vary the PWM control potentiometer and observe the output voltage across the load. 14. 3. Set the PWM duty cycle at minimum by varying Duty cycle control potentiometer. 5. Observe the variable DC voltage across the load. Switch OFF the Power supply unit. Verify the output DC voltage with the theoretical value. and capacitor current. Disconnect all the connections from the board. 7. Connect the Load RL1 and RL2 in parallel to load terminals.1: Minimum Maximum Minimum Pulse Maximum Pulse Frequency Frequency Width Width (Hz) (Hz) (%) (%) PROCEDURE FOR STUDYING THE FORWARD CONVERTER WITH VARIOUS LOADS. Connect +24V and ISO_GND to the Forward configuration. 4. 1. 9. Connect the output LC filter and observe the change in output voltage average value (using DMM) and the ripple voltage (on DSO). 12. 6. 15. 17. Observe the PWM at the output of optical isolation block with respect to ISO_GND. Switch ‘Off’ the power supply. 13. OBSERVATION TABLE 4. switch and diode. Connect the capacitor C1 between at the output. 16. Connect the GATE pulse to the gate of the IGBT. Switch on the instrument. PWM gets inverted at this point. 7. 5. Vary the frequency control potentiometer to observe frequency variation on oscilloscope. Vary the PWM control potentiometer at different pulse width. Repeat the experiment for different values of L . 10. Connect one end of inductor L1 and L2 in series to cathode of the diode D1. 6. 4. Observe the output of IGBT Driver block with respect ISO_GND. Make sure that there is no connection on the board initially. output capacitor (C1) ripple voltage. C and load values. switch (MOSFET) current. EEE/INSRT F342 Power Electronics Page 23 . 11. Connect the oscilloscope and vary the PWM control potentiometer & observe the waveforms of inductor current. Switch OFF the Power supply Unit. 8. 2. Switch ON the Power supply unit. Set the chopping frequency at 90 KHz by the frequency potentiometer. Capacitor PWM Output voltage across value Output voltage across No.2 Load = R1//R2 Ω Measured Measured Inductor Theoretical Measured S.2 with L1 .4 with L1+L2 . (µF) (%) Voltage the switch (µH) Voltage (V) the diode (V) (V) (V) 1 L1+L2 C1 20% 2 L1+L2 C1 40% 3 L1 C1 20% 4 L1 C1 40% GRAPHS 1. switch current. Draw the graphs of PWM output. Draw the graphs of PWM output. inductor current. capacitor current and voltage across the switch for duty ratio of 0.C1 and load for Forward converter and switching frequency 90kHz.C1 and load for Forward converter and switching frequency 90kHz. inductor current. OBSERVATION TABLE 4. capacitor current and voltage across the switch for duty ratio of 0. 2. switch current. EEE/INSRT F342 Power Electronics Page 24 . +5V@250mA SMPS: +/. Specification for the ST2730 Forward converter SMPS: +/.12V@ 500mA.NT → Reset winding (terLary winding) Power device : MOSFET IRF450 Diode : F4007 MOSFET/ IGBT Driver : C33153 Turn off Snubber : 100E 1W & 2. +5V@250mA SMPS: +/- 15V@1A SMPS: +24 V@1A for DC rail. 10x L1 L2 C1 C2 RL1 RL2 91uH 174uH 1000uF/63V 470uF/63V 75E /25W 75E /25W Please use external load for observing output power more than 15W. Input DC Voltage : 4V/1A PWM Frequency Variation : 8 KHz to 95 KHz Duty Cycle Variation : 8% to 35% Isolation 3 winding transformer: 6:10:6 ((NP:NS:NT) .12V@ 500mA. The maximum output power should not exceed 20W. EEE/INSRT F342 Power Electronics Page 25 .2nf 250V Rsense : 0.1Ω Power Isolation Section : Single channel. To study the performance of the Single Phase Bridge Controlled Rectifier with Ramp. Make sure that for all the measurements above 50V. Verify the type (AC/DC) before connection. with Lamp Load. Name ID No. b. CIRCUIT DIAGRAM: Figure 5. 5 STUDY OF SINGLE PHASE SEMI-CONTROLLED AND FULLY CONTROLLED RECTIFIER.1 Single Phase Semi-Converter EEE/INSRT F342 Power Electronics Page 26 . Voltage probes and clamp-on current probes (Tektronix A621) 6.No Batch No. EQUIPMENTS NEEDED 1. 4mm Patch Cords 4. To study the performance of the Single Phase Semi Converter with Ramp Comparator with (i) Lamp Load and (ii) Motor Load. Sec. EXPERIMENT No. Make sure use appropriate range in case of voltmeter/ammeter are within the proper range. Multimeter PRECAUTIONS: Sequences of the switching are to be followed. ST2700 High Voltage Power Electronics Lab set up 2. Oscilloscope 5. 2mm Patch Cord 3. Marks obtained Date Instructor’s signature OBJECTIVES a. power isolation section (Powerscope) provided on the set-up is to be used. Attenuation for the power isolation unit should be kept at 100x for voltages higher than 100V. Cosine Comparator. Make sure that Ammeters are connected in series with and Voltmeters are connected parallel across the load respectively. Verify the connections before switch on the MCB of single phase supply. Switch ATT of A is at ‘x 100’ position and switch of coupling of A should be at ‘DC’ position. 7. Connect BNC to BNC cable at CH1 of oscilloscope to output of Power Scope A. 1. 2. 12. 5. Connect Line Terminal (L) from single phase supply to anode of SCR1 or cathode of diode D2 and connect neutral terminal (N) to anode of SCR2 or cathode of diode D1. 10.1: Calculated Firing Measured Output S.No Type of Load Output Voltage Angle (α) Voltage (Vo) (Vo) 1 60o Lamp Load 2 90o 3 120o Motor Load 4 90o EEE/INSRT F342 Power Electronics Page 27 . 14. Make Connections according to Figure 4. 4. Connect gate pulse G3 at gate (G) of SCR2 and connect K3 at cathode of SCR2 from ramp comparator firing circuit. Repeat the steps 1-14 for Motor Load. Connect gate pulse G1 at gate (G) of SCR1 and connect K1 at cathode of SCR1 from ramp comparator firing circuit. Make sure that there is no connection on the board initially. 11. 9. Ammeter at the load. Switch on MCB of Single Phase Supply and observe the waveforms on the oscilloscope. 8. Connect the DC Voltmeter. 3. Connect input of Power Scope A to the load.1. OBSERVATION TABLE 5. Connect the one terminal of load from Load Assembly to common cathode terminal of SCR1 and SCR2 and other terminal of load is connect to common anode terminal of diode D1 and diode D2 . 6. Take the readings and tabulate in Observation Table 4. Connect the Lamp at the Load.1. In single phase semi converter common cathode configuration output load voltage is positive 0 to 205V DC variable (approximately) 13. PROCEDURE FOR STUDYING THE PERFORMANCE OF THE SINGLE PHASE SEMI-CONVERTER. 2. 2. 12.2 Single Phase Bridge Controlled Rectifier PROCEDURE FOR STUDYING THE PERFORMANCE OF THE SINGLE PHASE CONTROLLED RECTIFIER. 3. Repeat steps 1-14 using Cosine Comparator for lamp load. 11. Take the readings and tabulate in Observation Table 4.2. 5. Connect +12V. 8. Verify the connections before switch on the MCB of single phase supply. Make Connections according to Figure 4. Connect gate pulse G4 at gate (G) of SCR4 and connect K4 at cathode of SCR4 from ramp comparator firing circuit. Connect BNC to BNC cable at CH1 of oscilloscope to output of Power Scope A. it may lead to erroneous operation and may damage the system. 6. 4. Switch of ATT of A is at ‘x 100’ position and switch of coupling of A should be at ‘DC’ position. Connect gate pulse G1 at gate (G) of SCR1 and connect K1 at cathode of SCR1 from ramp comparator firing circuit. 10. Connect input of Power Scope A to the load. If not. Switch on MCB of Single Phase Supply and observe the waveform of load voltage on the oscilloscope. 1. 7. Make sure that there is no connection on the board initially. (Caution: Verify that the sequence of firing for the switches is in synchronism with the input voltage. Connect the DC Voltmeter. 9. Ammeter at the load. Connect the Lamp at the Load. Connect gate pulse G2 at gate (G) of SCR2 and connect K2 at cathode of SCR2 from ramp comparator firing circuit.) EEE/INSRT F342 Power Electronics Page 28 . CONNECTION DIAGRAM: Figure 5. +5V and ground (GND) and connect 18-0-18 at ramp comparator firing circuit from single phase low voltage power supply. Connect gate pulse G3 at gate (G) of SCR3 and connect K3 at cathode of SCR2 from ramp comparator firing circuit. 3. and Switch Voltage (VT1) with respect to time for full bridge rectifier with lamp load at 600. (c) Draw graphs of line voltage (VAN). Output Voltage (Vo). (b) Draw graphs of line voltage (VAN). Output Current (Io). (d) Draw graphs of line voltage (VAN). Output Current (Io). Output Voltage (Vo). and Switch Voltage (VT1) with respect to time for semiconverter with Lamp load at 600.No Vref Output Voltage Output Load Angle (α) (Vo) Voltage (Vo) 1 45o 2 60o Lamp Load 3 90o GRAPHS (a) Draw graphs of line voltage (VAN). and Switch Voltage (VT1) with respect to time for semiconverter with motor load at 900. Output Voltage (Vo). Output Current (Io). EEE/INSRT F342 Power Electronics Page 29 . Output Current (Io). Output Voltage (Vo). OBSERVATION TABLE 5.2 Ramp comparator firing scheme Measured Calculated Type of Firing S. and Switch Voltage (VT1) with respect to time for full bridge rectifier with motor load at 900. b. ST2700 High Voltage Power Electronics Lab 2. 4mm Patch Cords 3. Make sure that Analog Ammeter and Voltmeter are connected in series and parallel across load respectively. That is. PRECAUTIONS: Sequential order of switching is to be followed. Marks obtained Date Instructor’s signature OBJECTIVES a. 2mm Patch Cords. before the power circuit is energized. CONNECTION DIAGRAM: Figure 6.No Batch No. EQUIPMENTS NEEDED 1. Always turn on the High voltage three phase MCB before turning on the low voltage 3 phase MCB. Follow the reverse order while switching off. Heater load and lamp loads(4 lamps). Sec. To Study Three Phase Semi Converter with Lamp Load/heater load. Multimeter 6. do not apply gate signals. 6 STUDY OF THREE-PHASE SEMI CONVERTER Name ID No. EXPERIMENT No. Voltage probes and clamp-on current probes ((Tektronix A621) 5. Oscilloscope 4.1 Three Phase Semi Converter EEE/INSRT F342 Power Electronics Page 30 . To study of Three Phase Firing Circuit. Connect the R phase. Observe the gate pulses G3 with respect to K3 and G5 with respect to K5 with VRN as the time reference waveform. Switch on the oscilloscope.1. Observe the output of ramp generator at point of R. 9. Y phase. 2. Make the power circuit connections according to Figure 5. Connect CH2 of the oscilloscope to the gate pulse at G1 with respect to K1. Make sure that there is no connection on the board initially. 4. 7. Connect +12V and ground (GND) on three phase firing circuit from single phase low voltage power supply. 3. 5. 1. Connect the 4 lamps and heater load in series as the load to the converter. B phase and neutral (N) on three phase firing circuit from three phase low voltage power supply. Switch on the three phase MCB of back panel. 2 and 3 at point output of ramp comparator which is a square wave and another test point below it also shows square wave that is 180˚ phase shift to first square wave and by varying the firing angle control potentiometer vary the pulse width of square wave. PROCEDURE TO STUDY THE 3-PHASE FIRING CIRCUIT: Make sure that there is no connection on the Work Bench initially 1. If not. Vary the firing angle control potentiometer and observe the variation in gate pulse with respect to VRN. Connect the R phase. Connect +12V and ground (GND) on three phase firing circuit from single phase low voltage power supply. Switch on MCB of three phase low voltage power supply. Yellow and Blue indicator glow at front panel. B phase and neutral (N) on three phase firing circuit from three phase low voltage power supply. 6. 4. Connect BNC to Test Probe cable at CH1 of oscilloscope. Observe reference voltage at point Vref with respect to neutral vary the firing angle control potentiometer and observe the variation in Vref. Y phase. it may lead to erroneous operation and may damage the system. Observe the R phase.) PROCEDURE FOR STUDYING THE THREE PHASE SEMI CONVERTER. 8. 3. (Caution: Ensure that proper sequence of firing pulses are maintained for the switches.Y and B phase one by one at their respective test points with respect to neutral (N). Now connect CH1 of the oscilloscope to R with respect to N to measure VRN. Observe the output of ramp comparator 1. Y phase and B phase waveforms with respect to neutral. Connect the one terminal of load from load assembly to common cathode terminal of three phase semi converter and other terminal of load is connect to common anode terminal of three phase semi converter. 2. EEE/INSRT F342 Power Electronics Page 31 . Red. Keeping VRY in Power Scope A (and CH1) as time reference. Connect the DMM at the load to measure the output DC voltage across the load. Three phase high voltage MCB second and 1 phase MCB third.) 12. 13. Switch off the supply. connect gate pulse G3 at gate (G) of SCR2 and connect K3 at cathode of SCR2. Switch ‘ATT’ of A and B is to be kept at ‘x 100’ position and switch of coupling of A and B should be at ‘DC’ position. Connect BNC to BNC cable at CH1 of oscilloscope to output of Power Scope A and CH2 of oscilloscope to Power Scope B. Connect input of Power Scope A to the line voltage VRY( HV). 10. 8. Power on three phase low voltage power supply and single phase low voltage power supply and set the firing angle α= 45o with keeping VRN (low voltage) as the time reference. Disconnect G1-K1. 9. and IIN using CH2 with VRY as the time reference. 7. 6. Switch on MCB of Three Phase Supply and three phase low voltage power supply (respectively) and observe the waveforms on the oscilloscope. Switch off the MCBs in the reverse order. Switch off all the MCBs.No Output Output Output current Load Angle (α) Power (Po) factor Voltage (Vo) Voltage (Vo) Current (Io) IA(RMS) 1 45o Lamp 2 60o Load+ Heater 3 90o load EEE/INSRT F342 Power Electronics Page 32 . OBSERVATION TABLE 6.1: Vs(line-line)= V Measured Calculated Measured Input Type of Firing Output Power S. (Low voltage 3 phase MCB first. 11. and gate pulse G5 at gate (G) of SCR3 and connect K5 at cathode of SCR3 from three phase firing circuit. keeping the firing control knob at the same position. 5. Similarly. Repeat the procedure and note down Vo. G3-K3 and G5-K5 from the power circuit. Connect gate pulse G1 at gate (G) of SCR1 and connect K1 at cathode of SCR1 from three phase firing circuit. IT1. Now repeat steps 5-12 with α= 60o and 90o. Connect input of Power Scope B to the load. VD1. Verify the connections before switch on the MCB of single phase supply. connect Power scope B (and CH2) across VT1 and note the waveform. GRAPHS (a) Draw the graphs of Phase Voltage (VRN). and IIN with respect to time for α= 90o. VG5K5 for α=60o. VG3K3 . (b) Draw the graphs of Phase Voltage (VRN). and Thyristor Voltage (VT1) . EEE/INSRT F342 Power Electronics Page 33 . Line Voltage (VRY) Output Voltage (Vo). Line Voltage (VRY) waveforms and gate pulses VG1K1. Oscilloscope 5. CONNECTION DIAGRAM: Figure 7. Marks obtained Date Instructor’s signature OBJECTIVES a. To study single phase full wave ac voltage controller with (a) lamp load. Multimeter PRECAUTIONS: Make sure that Analog Ammeter and Voltmeter are connected in series and parallel across load respectively. 4mm Patch Cords 4. 2mm Patch Cord. (b) motor load. Voltage probes and clamp-on current probes ((Tektronix A621) 6. EQUIPMENTS NEEDED 1. EXPERIMENT No. Sec. b. To Study single phase cycloconverter with (a) lamp load (b) motor load. ST2700 High Voltage Power Electronics Lab 2.1 Single Phase Full-Wave Ac Voltage Controller EEE/INSRT F342 Power Electronics Page 34 . 7 STUDY OF SINGLE PHASE AC/AC CONVERTERS Name ID No.No Batch No. input current. voltage across SCR1. 5. 6. 4. Red. 8. Observe the Input voltage. 12. Switch on the three phase MCB of back panel. Figure 7. 2. PROCEDURE TO STUDY THE SINGLE PHASE FULL-WAVE AC VOLTAGE CONTROLLER CIRCUIT: Make sure that there is no connection on the Work Bench initially 1. Connect input of Power Scope A to the load. Connect gate pulse G1 at gate (G) of SCR1 and connect K1 at cathode of SCR1 from ramp comparator firing circuit. and output voltage at the load for various firing angles using multimeter. Connect +12V. voltage across SCR1. Connect the Lamp Motor at the Load. and output voltage at the load for various firing angles using CRO. Connect gate pulse G3 at gate (G) of SCR2 and connect K3 at cathode of SCR2 from ramp comparator firing circuit. 3. 9. 7. 11. Repeat the experiment with the motor load. Switch on MCB of Single Phase Supply and observe the waveforms of Input voltage. Yellow and Blue indicator glow at front panel. Verify the connections before switch on the MCB of single phase supply. 10.1. Connect the power circuit as per Figure 6.2 Single Phase Full-Wave Ac Voltage Controller EEE/INSRT F342 Power Electronics Page 35 . Switch of ATT of A is at ‘x 100’ position and switch of coupling of A should be at ‘DC’ position. Connect BNC to BNC cable at CH1 of oscilloscope to output of Power Scope A. 13. input current. Connect the AC Voltmeter at the load to measure the output AC voltage across the load. +5V and ground (GND) and connect 18-0-18 at ramp comparator firing circuit from single phase low voltage power supply. 1: AC/AC PHASE CONTROLLED CONVERTER Vs(line-line) = V Frequency of Input voltage = Hz Frequency of output voltage = Hz Measured Calculated Input Type of Firing S. Connect the Lamp at the Load. -5V and ground (GND) and connect 18-0-18 at cycloconverter firing circuit from single phase low voltage power supply. 7. 8. 4. 2. 6. Connect BNC to BNC cable at CH1 of oscilloscope to output of Power Scope A. Red. connect gate pulse G3 at gate (G) of SCR4 and connect K3 at cathode of SCR4.No Output Output current Load Angle (α) Voltage (Vo) Voltage (Vo) IA(RMS) 1 Lamp 1 + 60o Lamp 2 2 load 90o Motor 3 90o Load EEE/INSRT F342 Power Electronics Page 36 . OBSERVATION TABLE 7. Verify the connections before switch on the MCB of single phase supply. voltage across SCR1. Similarly. Switch on MCB of single phase supply and observe the waveforms of Input voltage. input current. 3. Connect input of Power Scope A to the load. and output voltage at the load for various firing angles using multimeter (AC mode). Connect gate pulse G1 at gate (G) of SCR1 and connect K1 at cathode of SCR1 from cycloconverter firing circuit. 10. gate pulse G2 at gate (G) of SCR2 and connect K2 at cathode of SCR2 and gate pulse G4 at gate (G) of SCR5 and connect K4 at cathode of SCR5. and output voltage at the load for various firing angles using CRO. Connect the AC Voltmeter at the load to measure the output AC voltage across the load. Switch of ATT of A is at ‘x 100’ position and switch of coupling of A should be at ‘DC’ position. Observe the Input voltage. input current. Yellow and Blue indicator glow at front panel. PROCEDURE TO STUDY THE SINGLE PHASE CYCLOCONVERTER CIRCUIT: Make sure that there is no connection on the Work Bench initially 1. Switch on the three phase MCB of back panel. 5.2. Connect the power circuit as per Fig. +5V. 6. 9. Connect +12V. MODEL WAVEFORM OBSERVATION TABLE 7.2: SINGLE PHASE CYCLOCONVERTER Vs(line-line) = V Frequency of Input voltage = Hz Frequency of output voltage = Hz Measured Calculated Input Type of Firing S.No Output Output current Load Angle (α) Voltage (Vo) Voltage (Vo) IA(RMS) Lamp 1 45o 1+ Lamp 2 2 60o Load EEE/INSRT F342 Power Electronics Page 37 . (d) Draw the graphs of the waveforms of Input voltage. input current. (c) Draw the graphs of the waveforms of Input voltage. and output voltage at the load for various firing angles for single phase cycloconverter with lamp load at 600. (b) Draw the graphs the waveforms of Input voltage. and output voltage at the load for various firing angles for single phase cycloconverter with lamp load at 900. input current. voltage across SCR1. voltage across SCR1. voltage across SCR1. MODEL WAVEFORM fs=3f0 GRAPHS (a) Draw the graphs the waveforms of Input voltage. and output voltage at the load for various firing angles for single phase full wave ac controller with lamp load at 60 0. input current. EEE/INSRT F342 Power Electronics Page 38 . voltage across SCR1. input current. and output voltage at the load for various firing angles for single phase full wave ac controller with lamp load at 900.