6 06000EE305122002 Pages: 3

Reg No.: Name:
APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY
Fifth Semester B.Tech Degree (S,FE) Examination January 2022 (2015 Scheme)

Course Code: EE305
Course Name: POWER ELECTRONICS

Max. Marks: 100 Duration: 3 Hours
(Graph sheets may be supplied on demand)
PARTA
Answer all questions, each carries 5 marks. Marks
1 With circuit diagram, explain the need of snubber circuit for SCR. (5)
2 Explain the operation of R triggering circuit for SCR with the help of circuit (5)

diagram and waveform

3 With circuit diagram, explain the 3-phase dual converter operating in (5)
circulating current mode.

4 Draw the circuit diagram for single phase full bridge voltage source inverter (5)
using IGBT with RL load. Also draw the waveforms for output voltage, output
current and input current. Show the device conduction in the waveform.

5 Explain the elimination of 17 order harmonics from the inverter output voltage (5)
using single pulse width modulation with suitable waveforms

6 With circuit diagram and waveforms, explain the two stage sequence control of (5)
AC voltage controller with R load

7 In a step-down chopper, voltage across the controlled switch is given in Fig.l. (5)

Determine the average output voltage.

| (1 [].

7 ms—>|
1 നട an டட. 1 ms = t
Fig. 1
8 Explain the PWM control and current limit control for the output control in (5)

chopper circuits.

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