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Unformatted text preview: Spring 2011 EEE472/591 – Power Electronics and Power
Due: Tuesday 2/22/11
Problem 1: (25 points)
Draw the average model of the converter shown below. Using the average model, calculate the
value of Vo and average input power in steady state. + 5A D = 0.4
f =100kHz + 100m F 10W Vo
_ Problem 2: (25 points)
Draw the average model of the converter shown below. Assume the initial current in the
inductor to be zero. Using the average model, draw the input current corresponding to the duty
ratio shown in the figure. I in q1 + 60 m H D = q1 0.1W
1- q1 + 30V 0.7
0 5ms t Problem 3: (25 points)
(a) Draw the small signal average model of the converter shown below at the given operating
conditions. Using this model derive the transfer function iin +
f 100kHz 100 H (s)
d (s) 0.2 42 V
+ 12V Problem 4: (25 points)
The specifications and the parameter values for a buck-boost converter are given below. It is
desired to regulate the output voltage constant at 30V.
Vin : 25V to 50V ;
Vo : 30V ; I o,max 10 A, I o,min 2 A
L 20 H , C 660 F , ESR 0.1 Design a controller based on K-Factor approach to achieve a bandwidth of 2 kHz and a phase
margin of 500. Comment on the choice 2 kHz for the bandwidth. Show Bode plots of plant, and
the overall loop gain with the designed controller.
Optional bonus point problem (30 points) (a) Study the performance of the control system designed in Problem 4 for step change in output
voltage reference from 30V to 32V. Show time domain PLECS/PSpice plots.
(b) Study the performance of the same system for step change in load current from 5A to 10A.
Show time domain PLECS/PSpice plots. ...
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This note was uploaded on 05/25/2011 for the course EE 472 taught by Professor Ayynar during the Spring '11 term at ASU.
- Spring '11