Re: Self-Resonant SSTC topologies

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "K. C. Herrick" <kchdlh-at-juno-dot-com> 

I'm glad to hear that IGBTs are speeding up.  Dave Leddon & I have been
playing with an idea of mine (not a new one, as Antonio de Queiroz noted
a few months ago) for charging MMC capacitors sequentially with a
commutator.  At this juncture, it's beginning to seem like a bum idea so
maybe I can summon some energy for trying a s.s. design yet again once
the dust settles (carbon dust, that is) from the current effort.  Unless,
of course, Dave or I come up with some success...

I still have the oil-drum handy-by in my carport.

Ken Herrick

On Mon, 17 May 2004 08:21:19 -0600 "Tesla list" <tesla-at-pupman-dot-com>
writes:
 > Original poster: "Steve Conner" <steve.conner-at-optosci-dot-com>
 >
 > Hi all
 >
 > A poster asked what was the prejudice against using IGBTs in SSTCs.
 > As far
 > as I know, IGBTs were simply too slow until about 6 months ago. They
 > could
 > not be used in SSTCs without special soft-switching schemes like
 > Vladimiro
 > Mazzilli's Royer SSTC.
 >
 > But the technology has advanced very quickly, and the newest ones
 > from
 > Fairchild are almost as fast as MOSFETs, free from dynamic latchup,
 > and have
 > a MOSFET-like square safe operating area too. This means they can
 > just be
 > dropped into an ordinary H-bridge and driven as if they were
 > MOSFETs.
 >
 > Also K.C. said:
 >
 >  >Be sure to provide a big enough container for receiving your
 >  >burned-out transistors.  I'd suggest a 55 gal. oil drum.
 >
 > If you go about things carefully, build your H-bridge with good
 > bypassing
 > and low-inductance layout, tune carefully to avoid leading power
 > factor, and
 > gradually work up to your design power, checking waveforms as you
 > go,
 > there's really no need to massacre legions of transistors. (Unless
 > you
 > decide to overdrive everything to get bigger sparks.)
 >
 > But I supposee us second-generation SSTCers are kind of spoilt.
 > People like
 > Richie Burnett, Gary Johnson, Jan Wagner, Alan Sharp, and K.C. have
 > already
 > done the pioneering, made the mistakes for us, and written nice
 > websites
 > telling us what not to do.
 >
 > Steve C.
 >
 >
 >