I am not too sure about it as the inductor was in my lab and it's not with me now.
But I think it should be fine, this schematic was originally obtained from an PFC chip board and it's working fine.
The components should be okie.

Most likely, there is a glitch in the control algorithm in the microcontroller.

Was wondering which part could it be...

 

How often are you sampling the ADC1 and ADC2? The more time between each measurement you make the more time the output has to overshoot.

Make sure you are taking measurements as rapidly as possible.

I suspect that since you are measuring voltage and current, you are also computing the power. This calculation may be taking too much time to make and this prevents you sampling the two ADCs at a rapid enough rate.

hgmjr

 

I am sampling both the ADC at the same frequency as the switching frequency.
I sample both the ADCs once at the start of every switching cycle.
After computing, I update the new duty cycle only at the start of the next switching cycle.

 

That seems a reasonable strategy to me.

hgmjr

 

You probably mentioned it and I just missed it. Which microcontroller did you end up using as the basis for your design?

hgmjr

 

am using the 16F877