Cc E192088 Pages:2

Reg No.:_ Name:

APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY
FIFTH SEMESTER B.TECH DEGREE EXAMINATION(R&S), DECEMBER 2019

Course Code: EE305
Course Name: POWER ELECTRONICS

Max. Marks: 100 Duration: 3 Hours
Graph sheet may be supplied on demand
PARTA
Answer all questions, each ೦0171055 marks. Marks
1 Sketch the static VI characteristics of SCR and define latching current and (5)
holding current.
2 Describe briefly the RC triggering circuit for SCR with a neat circuit diagram. (5)

With the help of a graph explain how firing angle control up to 180 degrees is

obtained.
Explain the operation of three-phase dual converter with circulating current.. (5)
+ Sketch the diagram and output voltage waveform of a single phase half bridge (5)

Voltage Source Inverter with R load and describe the working.
Define modulation index and Frequency modulation ratio. (5)
6 What are the control strategies for the regulation of output voltage in AC Voltage (5)

Controllers?

7 Explain the different methods by which control of output voltage is obtained in (5)
Choppers.
8 Derive the expression for the voltage gain in a Boost regulator. (5)
PART छ
Answer any two full questions, each carries10 marks.
9 8) Compare the characteristic features of MOSFET AND IGBT (4)
b) Give the structure and operation of TRIAC. (6)

10 a) Describe a single phase half controlled converter with RL load along with (4)
necessary circuit diagram and waveforms.
b) With neat circuit diagram explain the operation of a Single Phase Half Wave (6)
Rectifier with R, load. Sketch the shape of output voltage waveform.

11 a) Explain how di/dt and dv/dt protection is accomplished in SCR. (4)

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