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Re: DRSSTC Primary Circuit Feedback Control

Original poster: Terry Fritz <teslalist@xxxxxxxxxxxxxxxxxxxxxxx>

Hi Jimmy,

At 08:50 PM 12/6/2004, you wrote: 
Hi Terry,

The little IGBTs should be practical anyway. Based on some
measurements taken on my DRSSTC, I'm convinced that a half bridge of
little TO-247 IGBTs could get me to 5'.

You have to be a little careful with primary feedback, because if it
isn't tuned, the secondary won't be sucking much out, and it will
build up more than normal

Yes!! The models show that for sure. If the primary and secondary are not tuned, then the primary voltage just keeps rising pretty much till something blows up!! A spark gap might "still" be a good idea ;-))

The models (not real confident in the numbers..) say the IGBTs will do about 40 watts of heat as is. But with "perfect" zero cross switching, that goes down to 1.2 watts!! This is no different than any other switching resonant thing and they are all using "little" FETS and IGBTs... We just have to refine ours... I also seem to be able to keep the peak primary currents at just 80 amps which is trivial for the IGBTs. Almost could use FETs again...

Cheers,

Terry