Anna University
Department of EEE
Semester : 5
Year : 3
Department : B.E EEE
POWER ELECTRONICS Monthly Test QUESTION PAPER
PART A
1. What is the effect of source impedence on single phase converter?
2. Define the term duty cycle in dc-dc converter.
3. What is meant by buck regulator?
4. What is meant by resonsnt switching?
5. Compare zcs & zvs.
6. What is time ratio control?
7. What are the applications of chopper?
8. What are the control stratergies of chopper?
9. A step up chopper has input voltage of 220V and output voltage of 660V , If the non-conducting period of thyristor chopper is 100µs, compute the pulse width of o/p voltage.
10. Difference between vsi & csi
PART B
1. (a) Explain the effect of source impedence in 3 phase convtr with ckt diagram & waveform.
or
(b) Effect of source impedence on 1 phase convtr with ckt diagram & waveform.
2. (a) Explain dual converter with circulating and non circulating modes.
or
(b) Draw the ckt diag of boost converter & explain its operation with equivalent ckt for different modes and waveforms.
3. (a) Draw the ckt diag of buck-boost convtr & explain its oprtn with eqvlt ckt for different modes & waveforms.
or
(b)Explain zvs with neat diag & waveform.
4. (a)Draw the ckt diagram of a buck converter & explain its operation with equivalent ckt for different modes and waveforms.
or
(b) Describe the principle of operation of dc-dc step up chopper with suitable waveforms. Derive an expression for the average o/p vt in terms of i/p dc vt & duty cycle.
5. (a)(i)Discuss the principle of operation of dc-dc step down chopper with suitable waveforms. Derive an expression for the average o/p vt.
(ii) A step down chopper has i/p vt of 230V with 10Ω load resistor connected. the vt drop across the chopper is 2V when it is ON. for a duty cycle of 0.5, calculate avg rms value of o/p vt & power delivered to the lolad.
or
(b) Explain single phase voltage source inverter.