Download GTU BE/B.Tech 2019 Winter 3rd Sem New 2132404 Principles Of Power Electronics Question Paper

Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2019 Winter 3rd Sem New 2132404 Principles Of Power Electronics Previous Question Paper

1
Seat No.: ________ Enrolment No.___________

GUJARAT TECHNOLOGICAL UNIVERSITY

BE - SEMESTER ? III (New) EXAMINATION ? WINTER 2019
Subject Code: 2132404 Date: 7/12/2019

Subject Name: Principles of Power Electronics
Time: 02:30 PM TO 05:00 PM Total Marks: 70
Instructions:

1. Attempt all questions.

2. Make suitable assumptions wherever necessary.

3. Figures to the right indicate full marks.

Q.1 (a) Define Power electronics. Draw the block diagram of typical power
electronics system.
03
(b) Explain Zener diode and state its applications. 04
(c) List and explain ideal and practical switch characteristics. 07

Q.2 (a) Describe gate-triggering of a thyristor. 03
(b) State merits and demerits of power electronic converters. 04
(c) Describe reverse recovery characteristics of diodes. Shows that
reverse recovery time and peak inverse time are depending upon
storage charge and rate of change of current.
07
OR
(c) What is p-n junction? Discuss the formation of depletion layer in p-n
junction.

07
Q.3 (a) What do you understand by Q-point? What is its significance? 03
(b) Draw and explain V-I characteristics of SCR. 04
(c) Give the classification of turn-on methods of SCR. Explain any one in
detail.
07
OR
Q.3 (a) Differentiate between hard switching and soft switching of transistor. 03
(b) Explain I-V characteristics of power transistor. 04
(c) Explain switching characteristics of SCR. 07

Q.4 (a) What is commutation? Why commutation required in thyristor? 03
(b) Explain concept of safe operating area (SOA). 04
(c) Enlist different commutation methods of SCR. Explain any one in
detail.
07
OR
Q.4 (a) Describe R-triggering of a thyristor. 03
(b) Explain snubber circuit in SCR. 04
(c) Explain two transistor analogy in SCR with necessary equations. 07
Q.5 (a) Draw the I-V characteristics of TRIAC and state its applications. 03
(b) Explain primary and secondary breakdown in BJT. 04
(c) Explain construction and working of GTO in detail. 07
OR

Q.5 (a) Explain construction of enhancement type MOSFET 03
(b) Explain Varactor diode. 04
(c) Explain series and parallel operation of SCR in detail. 07


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