Buck Boost Converter with PI control

http://img97.imageshack.us/img97/9180/buckboostconverter.jpg

Hi all,

I am trying to implement a PI controller to regulate the output voltage of a Buck Boost Converter. The link shows my circuit layout. The way i implemented the PI controller with PWM works on a buck converter.

However, when i switch it to a buck boost converter, it doesnt work. From what i see, there is no output being feedback to the sum-er to be added to the Vref of 20V.

Appreciate any help on this, as i have been stuck at this problem for days.

Answer 1

[SUDHAKAR REDDY AKKI]

What ever you done is wrong. so, just Replace the the Power switch and inductor ...

Answer 2

[G.A Chaudhry]

the direction of the diode is not correct if u r considering buck-boost topology as well.