POWER ELECTRONICS
QUESTION BANK
1. Explain the dynamic characteristics of SCR with neat waveforms
2. Draw and explain V-I characteristics of SCR and its working.
3. Explain the types of power electronic converters.
4. Write short note on applications of power electronic converters
5. Discuss the method of triggering of SCR
6. Define Latching current and Holding current.
7. Write short note on Turn on methods of SCR.
8. Write a short note on firing circuit(R –firing circuit)
9. Write a short note on firing circuit (RC –firing circuit)
10. Explain the method of protection of thermistor in details
11. Draw and explain turn off characteristics of SCR
12. Define rise time ,delay time ,peak time, and settling time
13. Why RC firing is better than R- firing circuit
14. What are the advantages of RC -firing circuit
15. What are the function of snubber circuit
16. What are the draw backs of R- firing circuit
17. What are function of freewheeling diode
18. List the different application of phase controlled converters.
19. Explain the operation of single phase fully controlled rectifier with R load and also derive
the average and RMS load voltage.
20. Explain the operation of single phase fully controlled rectifier with L load and also derive
the average and RMS load voltage.
21. Explain the operation of single phase fully controlled rectifier with RL load and also derive
the average and RMS load voltage.
22. Explain the operation of single phase fully controlled rectifier with RLE load and also derive
the average and RMS load voltage.
23. Explain the operation of three phase fully controlled rectifier with R load and also derive the
average and RMS load voltage.
24. Describe the principle of chopper operation.
25. Explain the single phase half bridge voltage source inverter with necessary waveforms
26. List some applications of dc chopper?
27. What are the applications of inverters?
28. Describe the working of single phase full bridge inverter with neat waveform
29. What are the difference between power diode and signal diode
30. Write short note on ideal switch
31. Write short note on practical
32. Difference between ideal and practical switch
33. Derive the expression of switching losses
34. Derive the expression of conduction losses
35. Explain different types of losses
36. Write short notes on conduction losses
37. Difference between unipolar and bipolar switch
38. Difference between unidirectional and bidirectional switch
39. Write two properties of ideal switch
40. What is an inverter?
41. What is the principle of operation of an inverter?
42. What are the types of inverters?
43. What are the differences between half-bridge and full-bridge inverters?
44. Explain 120 degree conduction mode of operation of three phase inverter
45. Explain 180 degree conduction mode of operation of three phase inverter
46. What are the difference between voltage source converter and current source inverter
47. What is chopper
48. Write two application of chopper
49. Explain buck converter
50. Explain boost converter
51. Explain buck-boost converter
52. Explain step up copper
53. Explain step down up copper
54. Explain class A commutation in details
55. Explain class B commutation in details
56. Explain class C commutation in details
57. Explain class D commutation in details
58. What is a converter?
59. What is turn-off time of a thyristor?
60. What is power electronics
61. What are the various types of thyristors?
62. What is a commutation circuit?
63. What are the conditions for a thyristor to conduct
64. How can a conducting thyristor be turned off
65. What is a line commutation?
66. What is a forced commutation?
