Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2019 Winter 6th Sem New 2161006 Power Electronics Devices And Circuits Previous Question Paper
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ? VI (New) EXAMINATION ? WINTER 2019
Subject Code: 2161006 Date: 09/12/2019
Subject Name: Power Electronics Devices and Circuits
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) Draw only the symbols of the following:
(i) DIAC
(ii) UJT
(iii) SCR
03
(b) Explain the switching characteristics of SCR. 04
(c) Discuss the advantages and limitations of IGBT. 07
Q.2 (a) Write the advantages of LASCR. 03
(b) How SCR can be turned off using natural commutation method? 04
(c) Explain the UJT as relaxation oscillator with appropriate diagrams. 07
OR
(c) Discuss the protection circuits of SCR under transient conditions. 07
Q.3 (a) Why a freewheeling diode is connected in inductive loaded circuit? 03
(b) Draw the circuit diagram of three phase half wave controlled
rectifier with R load.
04
(c) Explain the construction, operation and characteristics of GTO. 07
OR
Q.3 (a) Write the applications of dc-dc converters. 03
(b) Explain the operation of type A chopper. 04
(c) Explain the single phase full wave controlled rectifier with RL load
with proper waveforms.
07
Q.4 (a) What are the performance measures of inverters? 03
(b) Explain the basic principle of operation of cycloconverter. 04
(c) Explain different control strategies for chopper operation. 07
OR
Q.4 (a) Explain step up dc-dc converter with circuit diagram. 03
(b) Draw only circuit diagram of three phase to single phase
cycloconverter.
04
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Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ? VI (New) EXAMINATION ? WINTER 2019
Subject Code: 2161006 Date: 09/12/2019
Subject Name: Power Electronics Devices and Circuits
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) Draw only the symbols of the following:
(i) DIAC
(ii) UJT
(iii) SCR
03
(b) Explain the switching characteristics of SCR. 04
(c) Discuss the advantages and limitations of IGBT. 07
Q.2 (a) Write the advantages of LASCR. 03
(b) How SCR can be turned off using natural commutation method? 04
(c) Explain the UJT as relaxation oscillator with appropriate diagrams. 07
OR
(c) Discuss the protection circuits of SCR under transient conditions. 07
Q.3 (a) Why a freewheeling diode is connected in inductive loaded circuit? 03
(b) Draw the circuit diagram of three phase half wave controlled
rectifier with R load.
04
(c) Explain the construction, operation and characteristics of GTO. 07
OR
Q.3 (a) Write the applications of dc-dc converters. 03
(b) Explain the operation of type A chopper. 04
(c) Explain the single phase full wave controlled rectifier with RL load
with proper waveforms.
07
Q.4 (a) What are the performance measures of inverters? 03
(b) Explain the basic principle of operation of cycloconverter. 04
(c) Explain different control strategies for chopper operation. 07
OR
Q.4 (a) Explain step up dc-dc converter with circuit diagram. 03
(b) Draw only circuit diagram of three phase to single phase
cycloconverter.
04
2
(c) Draw and explain the series inverter with proper waveforms. 07
Q.5 (a) Draw the block diagram of microcontroller based control of DC
drives.
03
(b) Explain the concept of sinusoidal pulse width modulation. 04
(c) Draw and explain the circuit of battery charger. 07
OR
Q.5 (a) Explain basic principle of dielectric heating. 03
(b) Differentiate between online and offline UPS systems. 04
(c) Compare various speed control techniques for AC motor drives. 07
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This post was last modified on 20 February 2020