Download GTU B.Tech 2020 Winter 7th Sem 171002 Power Electronics Question Paper

Download GTU (Gujarat Technological University Ahmedabad) B.Tech/BE (Bachelor of Technology/ Bachelor of Engineering) 2020 Winter 7th Sem 171002 Power Electronics Previous Question Paper

Seat No.: ________
Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE- SEMESTER?VII (OLD) EXAMINATION ? WINTER 2020
Subject Code:171002 Date:21/01/2021
Subject Name:Power Electronics
Time:10:30 AM TO 12:30 PM Total Marks: 56
Instructions:
1. Attempt any FOUR questions out of EIGHT questions.

2. Make suitable assumptions wherever necessary.

3. Figures to the right indicate full marks.
Q.1 (a) Explain the principle of operation of SCR with (i) Device structure (ii)
07
Characteristics.

(b) Explain the construction and characteristics of IGBT.
07



Q.2 (a) What is the need of commutation in SCR circuits? Explain the class-B
07
commutation in detail.

(b) Draw and explain the structure of power MOSFET. Also explain principle of
07
operation and I-V characteristics of power MOSFET



Q.3 (a) What are the various thyristor ratings?
07

(b) What is GTO ? Draw and Explain GTO structures . Also explain
07
GTO Turn off mechanism with desired equation and figures.




Q.4 (a) Discuss the two transistor model of a Thyristor. Derive an expression for the
07
anode current and henceforth discuss the turn ON mechanism of a Thyristor.

(b) Explain series and parallel operations of thyristor?
07



Q.5 (a) What is chopper? Describe the working of Type C chopper.
07

(b) Explain R and RC firing circuit of SCR.
07



Q.6 (a) Explain principle of operation of step-down DC chopper.
07

(b) Write short note on three phase inverter.
07



Q.7 (a) Write short note on RF heating.
07

(b) Write short note on Uninterruptible Power Supply.
07



Q.8 (a) Explain the circuit diagram and working of single phase semi converter with
07
freewheeling diode.
(b) Write short notes on dielectric heating and induction heating
07
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