Hello everybody!
I have a problem with boost converter. I can get max 90V from 20V source and then all circuit colapses and output mosfet get shorted. Output voltage changes in dependence on choke but i could never get 220V from 20V source.
Also, audible noise form choke is present while adjusting output voltage,
Do you have idea what's going on here?

 

Without a circuit diagram, I have no idea what are you talking about. From your description, are you using low frequency oscillation for your converter, like <1 KHz ?

BTW, what is your load?

Allen

 

Measure the inductor current. See if it's saturating when increasing the PWM pulse width. If that's the case increase inductance or frequency.

And yes, we need a schematic.