GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER-VII (Old) EXAMINATION - WINTER 2019
--- Content provided by FirstRanker.com ---
Subject Code: 171002 Date: 26/11/2019
Subject Name: Power Electronics
Time: 10:30 AM TO 01:00 PM Total Marks: 70
Instructions:
- Attempt all questions.
- Make suitable assumptions wherever necessary.
- Figures to the right indicate full marks.
--- Content provided by FirstRanker.com ---
Q.1 (a) Explain the Thyristor dynamic characteristic. [07]
(b) Explain R and RC trigger circuits for SCR with suitable waveform. [07]
Q.2 (a) Discuss the two transistor model of a Thyristor and also derive the expression for the anode current. [07]
--- Content provided by FirstRanker.com ---
(b) Explain the operation of GTO with relevant diagram. [07]OR
(b) Explain the series parallel operation of thyristor. [07]
Q.3 (a) What is chopper? Describe the working of Type A chopper. [07]
(b) What is commutation? Explain with relevant waveforms class B commutation. [07]
--- Content provided by FirstRanker.com ---
OR
Q.3 (a) Describe the construction and working of IGBT. Also enumerate the advantages of IGBT over BJT and MOSFET [07]
(b) Explain Single phase Full (Bridge) controlled rectifier with resistive load in detail. [07]
Q.4 (a) Describe the working of single phase half Bridge inverter. What is its main drawback? Explain how this drawback is overcome? [07]
(b) Describe the operation of three-phase inverter with 180-Degree conduction [07]
--- Content provided by FirstRanker.com ---
OR
Q.4 (a) Describe the operation of single phase half wave controlled rectifier using SCR for RL load and RL load with freewheeling diode. [07]
(b) What is the principle of operation of step-up chopper? Explain with wave form. [07]
Q.5 (a) What are the causes of overvoltage and overcurrent? Describe the method used for overvoltage protection of SCR. [07]
(b) Describe Switched mode power supply with necessary diagrams in detail [07]
--- Content provided by FirstRanker.com ---
OR
Q.5 (a) What is forced commutation? With help of circuit diagram and necessary waveform. Explain the auxiliary (Class D) commutation. [07]
(b) List out turn on and turn off methods for thyristor. [07]
--- Content provided by FirstRanker.com ---
This download link is referred from the post: GTU BE/B.Tech 2019 Winter Question Papers || Gujarat Technological University