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Power Electronics Assignment

This document contains an assignment with 6 questions regarding high frequency power electronic converters. Question 1 asks to design a flyback converter operating in continuous current mode. Question 2 derives an expression for when the magnetizing current returns to zero in discontinuous current mode flyback converter. Question 3 calculates the switch voltage rating for a forward converter with maximum duty cycle. Question 4 provides parameters for a forward converter and asks to determine various currents and voltages. Question 5 designs a forward converter with given specifications. Question 6 asks to simulate an active clamp forward converter in PSIM and show relevant waveforms.

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110 views1 page

Power Electronics Assignment

This document contains an assignment with 6 questions regarding high frequency power electronic converters. Question 1 asks to design a flyback converter operating in continuous current mode. Question 2 derives an expression for when the magnetizing current returns to zero in discontinuous current mode flyback converter. Question 3 calculates the switch voltage rating for a forward converter with maximum duty cycle. Question 4 provides parameters for a forward converter and asks to determine various currents and voltages. Question 5 designs a forward converter with given specifications. Question 6 asks to simulate an active clamp forward converter in PSIM and show relevant waveforms.

Uploaded by

anishth
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as PDF, TXT or read online on Scribd
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THE UNIVERSITY OF WESTERN ONTARIO

FACULTY OF ENGINEERING

DEPARTMENT OF ELECTRICAL AND COMPUTER ENGINEERING

ECE 9403/9043a - HIGH FREQUENCY POWER ELECTRONIC CONVERTERS

Assignment #2

Answer all questions. All questions are of equal value.

1. A flyback converter is to be designed so that it operates in continuous "current" (flux) mode


with a duty cycle of D = 0.45 when input voltage Vs = 48 V, output voltage Vo = 30 V,
switching frequency fs = 25 kHz, and load resistor R = 15 . Determine the necessary
transformer turns ratio and transformer magnetizing inductance that will make the minimum
inductor current to be 25% of the average. Confirm your answer with PSIM.

2. For the flyback converter operating in the discontinuous "current" (flux) mode, derive an
expression for the time at which the magnetizing current returns to zero.

3. A forward converter with a demagnetizing winding is designed to operate with a maximum


duty cycle of D = 0.7. Calculate the voltage rating of the switch in terms of the input voltage.

4. A forward converter has the following parameters: input source voltage Vs = 100 V, N1/N2 =
N1/N3 = 1, magnetizing inductance Lm = 5 mH, output inductor Lo = 200 H, Co = 100 F, D
= 0.35, and switching frequency fs = 50 kHz. If the output current is continuous then do the
following:
(a) Determine the output voltage.
(b) Determine the average, maximum, and minimum current in the inductor.
(c) Determine the peak magnetizing current.
(d) Determine the peak switch current.
Confirm your answers with PSIM.

5. A switch-mode power supply is to be designed with the following specifications: input


voltage Vs = 48 V 10%, output voltage Vo = 5 V, switching frequency fs = 100 kHz, output
power Po = 15-50 W. A forward converter operating in a continuous current mode with a
demagnetizing winding of N3 = N1 is to be used. Assume all components to be ideal except
for the presence of the transformer magnetization inductance.
(a) Calculate N2/N1 if this turns ratio is desired to be as small as possible.
(b) Calculate the minimum value of the filter inductance.

6. Simulate an active clamp forward converter using PSIM. You may use any component values
and converter parameters that you wish. Show all pertinent waveforms.

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