Quote Originally Posted by barkerben
Oh yes, that was it... I remember now.

We had 24v in, chopped using a full bridge to 20Khz AC, fed into a transformer, then rectified to high voltage DC using a diode ring. The ide of high frewuency was to reduce transofrmer size and losses. The high voltage DC was then chopped usign a second H bridge to a quasi sine output.

The trigger signals for both bridges were generated by the PIC. We wanted to replace the quasi sine bridge trigge with full sine, but never got around to it :-(
That was good!!! U should have made the output of hi freq. transformer centre tapped and used bridge to get dual supply i.e. +/- side. This requires
only half bridge ckt and only 2nos of Hi voltage Mosfets and get good sine wave
from it.(U require small inductor/capacitor filter for non inductive loads.) Again U can prevent the Mosfets from frying with including some current limiter in HT side rectified high voltage rather than spraying freezant.