Yashwantrao Chavan Maharashtra Open University 2006 Certification TES Power Electronics - II - Question Paper

TES102/EE/20070813
Power Electronics - II
Time : 180 minutes Marks : 100
Instructions for the students :
1. All ques. are compulsory.
2. “Long ans kind ques. (LAQ)” is a supply kind ques. of 20 marks, which
require typical ans of about 60-80 lines in about 32-40 minutes.
3. “Short ans kind ques. (SAQ)” is a supply kind ques. of five marks, which
require typical ans of about 15-20 lines in about 08-10 minutes.
4. Use of non-programmable kind of scientific calculator is allowed.
5. Draw neat diagrams wherever necessary.
6. presume suitable data if necessary.

Long ans kind ques. (LAQ’s)

1. (a) discuss the operation of single phase full bridge inverter with the
help of voltage waveforms.
(b) Draw and discuss the operation of replaced McMurray Bedford Full
Bridge Inverter.

2. (a) discuss the continuous and non-continuous conduction mode of
kind A chopper.
(b) Draw and discuss voltage commutated Chopper with associated
waveforms.

3. (a) discuss with the help of a circuit diagram how a diac is used as a
triggering agent for a triac.
(b) Draw V-I characteristics of a diac and discuss its working principle.
(c) List the advantages and disadvantages of triac over SCR.
(d) Draw and discuss the V-I characteristics of an SCS.

4 (a) With the help of a circuit diagram discuss the operation of a Buck
Converter.
(b) define briefly the latch up’s in an IGBT.
(c) discuss briefly the different over-voltage conditions of an SCR.
(d) What is a Heat Sink ? elaborate the various mounting techniques?


Short ans kind ques. (SAQ’s)

5. provide the limitations of Series Inverter. 5
6. provide the advantages of Jones Chopper over other Chopper Circuits. provide
its applications.

7. discuss the difference ranging from Phase Control Thyristors and Inverter
Grade Thyristors.

8. Write a short note on 2nd Breakdown Phenomenon in a Power BJT.

Earning:   Approval pending.