Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2018 Winter 5th Sem Old 150903 Power Electronics I Previous Question Paper
1
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?V (OLD) EXAMINATION ? WINTER 2018
Subject Code:150903 Date: 16/11/2018
Subject Name: Power Electronics - I
Time: 10:30 AM TO 01:00 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) Explain construction & working of a SCR. Discuss two transistor analogy. 07
(b) Explain the characteristic ,working and construction of IGBT. 07
Q.2 (a) Explain DIAC with its construction and V-I characteristic. 07
(b) Explain pulse transformer and opto-coupler. 07
OR
(b) Write a short note on the current ratings and voltage ratings of thyristor. 07
Q.3 (a) Explain the resistance triggering and R-C triggering method. What is advantage of
RC triggering over resistance triggering?
07
(b) Explain the turn-on and turn-off characteristics of an SCR. 07
OR
Q.3 (a) With neat circuit diagram & waveform explain UJT oscillator triggering. 07
(b) Write a short note on buck-boost converter. 07
Q.4 (a) What is chopper? Explain step-up chopper. 07
(b) With a neat circuit diagram and waveforms describe the Morgan?s Chopper circuit.
State its applications & limitations.
07
OR
Q.4 (a) Describe the working principle of Jones chopper with neat circuit diagram. 07
(b) Explain in brief various control strategies of a chopper. 07
Q.5 (a) Discuss four quadrant operations of DC drives. 07
(b) Explain phase locked loop (PLL) control of dc motor. 07
OR
Q.5 (a) Explain how regenerative braking can be achieved for a separately excited DC
motor using DC-DC converter.
07
(b) With neat circuit diagram and waveforms, explain the operation of a two-quadrant
chopper capable to give forward motoring and forward regenerative operation.
07
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This post was last modified on 20 February 2020