Code No: RR310204 RR Set No. 2
III B.Tech I Semester Supplementary Examinations,June 2010
POWER ELECTRONICS Electrical And Electronics Engineering
Time: 3 hours Max Marks: 80
Answer any FIVE Questions
All Questions carry equal marks
? ? ? ? ?
1. A chopper circuit is operating on Time Ratio Control (TRC) principle at a fre- quency of 2KHz on a 220V dc supply. If the load voltage is 170V. Compute the conduction and blocking period of thyristor in each cycle. [16]
2. (a) Compare mid-point converters and bridge type converters and bring out im- portant features.
(b) Compare discontinuous and continuous current modes of operation of convert- ers and bring out salient features. [8+8]
3. (a) What are the different pulse width modulation techniques used for inverters. (b) Which of the schemes gives better quality of voltage and current. [10+6]
4. Draw and explain the simple SCR series inverter circuit employing class A type commutation. With the help of important waveforms. State the limitations of this inverter. [16]
5. Derive the output rms voltage, output rms current and source power factor for a single phase ac voltage controller fed to R-L load. [16]
6. (a) What is a cyclo converter?
(b) What are the varieties of single phase cyclo converters. (c) What are the salient features of cyclo converters.
(d) What are the major limitations of cyclo converters [4+4+4+4]
7. Explain the operation of three phase half-wave controlled converter with resistive load, and inductive load. Sketch the associated waveforms. [16]
8. A rectangular pulse of 30V with 10 us duration is applied at the gate. The average gate power dissipation of the thyristor is 0.5W and a peak gate drive power is 5W. Calculate the values of the series resistance to be connected in the gate circuit, the frequency and duty cycle of the triggering pulse. [16]
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1
Code No: RR310204 RR Set No. 4
III B.Tech I Semester Supplementary Examinations,June 2010
POWER ELECTRONICS Electrical And Electronics Engineering
Time: 3 hours Max Marks: 80
Answer any FIVE Questions
All Questions carry equal marks
? ? ? ? ?
1. Derive the output rms voltage, output rms current and source power factor for a single phase ac voltage controller fed to R-L load. [16]
2. (a) What is a cyclo converter?
(b) What are the varieties of single phase cyclo converters. (c) What are the salient features of cyclo converters.
(d) What are the major limitations of cyclo converters [4+4+4+4]
3. (a) Compare mid-point converters and bridge type converters and bring out im- portant features.
(b) Compare discontinuous and continuous current modes of operation of convert- ers and bring out salient features. [8+8]
4. (a) What are the different pulse width modulation techniques used for inverters. (b) Which of the schemes gives better quality of voltage and current. [10+6]
5. A chopper circuit is operating on Time Ratio Control (TRC) principle at a fre- quency of 2KHz on a 220V dc supply. If the load voltage is 170V. Compute the conduction and blocking period of thyristor in each cycle. [16]
6. Draw and explain the simple SCR series inverter circuit employing class A type commutation. With the help of important waveforms. State the limitations of this inverter. [16]
7. A rectangular pulse of 30V with 10 us duration is applied at the gate. The average gate power dissipation of the thyristor is 0.5W and a peak gate drive power is 5W. Calculate the values of the series resistance to be connected in the gate circuit, the frequency and duty cycle of the triggering pulse. [16]
8. Explain the operation of three phase half-wave controlled converter with resistive load, and inductive load. Sketch the associated waveforms. [16]
? ? ? ? ?
2
Code No: RR310204 RR Set No. 1
III B.Tech I Semester Supplementary Examinations,June 2010
POWER ELECTRONICS Electrical And Electronics Engineering
Time: 3 hours Max Marks: 80
Answer any FIVE Questions
All Questions carry equal marks
? ? ? ? ?
1. (a) Compare mid-point converters and bridge type converters and bring out im- portant features.
(b) Compare discontinuous and continuous current modes of operation of convert- ers and bring out salient features. [8+8]
2. (a) What are the different pulse width modulation techniques used for inverters. (b) Which of the schemes gives better quality of voltage and current. [10+6]
3. A rectangular pulse of 30V with 10 us duration is applied at the gate. The average gate power dissipation of the thyristor is 0.5W and a peak gate drive power is 5W. Calculate the values of the series resistance to be connected in the gate circuit, the frequency and duty cycle of the triggering pulse. [16]
4. Derive the output rms voltage, output rms current and source power factor for a single phase ac voltage controller fed to R-L load. [16]
5. Draw and explain the simple SCR series inverter circuit employing class A type commutation. With the help of important waveforms. State the limitations of this inverter. [16]
6. (a) What is a cyclo converter?
(b) What are the varieties of single phase cyclo converters. (c) What are the salient features of cyclo converters.
(d) What are the major limitations of cyclo converters [4+4+4+4]
7. Explain the operation of three phase half-wave controlled converter with resistive load, and inductive load. Sketch the associated waveforms. [16]
8. A chopper circuit is operating on Time Ratio Control (TRC) principle at a fre- quency of 2KHz on a 220V dc supply. If the load voltage is 170V. Compute the conduction and blocking period of thyristor in each cycle. [16]
? ? ? ? ?
3
Code No: RR310204 RR Set No. 3
III B.Tech I Semester Supplementary Examinations,June 2010
POWER ELECTRONICS Electrical And Electronics Engineering
Time: 3 hours Max Marks: 80
Answer any FIVE Questions
All Questions carry equal marks
? ? ? ? ?
1. Explain the operation of three phase half-wave controlled converter with resistive load, and inductive load. Sketch the associated waveforms. [16]
2. A rectangular pulse of 30V with 10 us duration is applied at the gate. The average gate power dissipation of the thyristor is 0.5W and a peak gate drive power is 5W. Calculate the values of the series resistance to be connected in the gate circuit, the frequency and duty cycle of the triggering pulse. [16]
3. Draw and explain the simple SCR series inverter circuit employing class A type commutation. With the help of important waveforms. State the limitations of this inverter. [16]
4. Derive the output rms voltage, output rms current and source power factor for a single phase ac voltage controller fed to R-L load. [16]
5. (a) What are the different pulse width modulation techniques used for inverters. (b) Which of the schemes gives better quality of voltage and current. [10+6]
6. (a) What is a cyclo converter?
(b) What are the varieties of single phase cyclo converters. (c) What are the salient features of cyclo converters.
(d) What are the major limitations of cyclo converters [4+4+4+4]
7. A chopper circuit is operating on Time Ratio Control (TRC) principle at a fre- quency of 2KHz on a 220V dc supply. If the load voltage is 170V. Compute the conduction and blocking period of thyristor in each cycle. [16]
8. (a) Compare mid-point converters and bridge type converters and bring out im- portant features.
(b) Compare discontinuous and continuous current modes of operation of convert- ers and bring out salient features. [8+8]
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