Re: OLTC Maggy modelling

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

Original poster: "Stephen Conner by way of Terry Fritz <teslalist-at-qwest-dot-net>" <steve-at-scopeboy-dot-com>

At 17:04 11/04/03 -0600, you wrote:
>Original poster: "boris petkovic by way of Terry Fritz 
><teslalist-at-qwest-dot-net>" <petkovic7-at-yahoo-dot-com>
>
> > Which is exactly what we want! Unfortunately, doing
> > this in real life
> > requires two IGBTs in series, each with a diode in
> > series. That's four bits
> > of silicon in series, thus about three times the
> > cost, and roughly six
> > times the losses of a single IGBT carrying the same
> > current.
>---
>Bummer.. I admit I didn't give a thought to that.
>You think there isn't primary circuit way to prevent
>this (except getting "IGBT bricks")?

I got this slightly wrong. Actually the effective circuit is one IGBT and 
one diode in series, for about 1.5x the losses of a single IGBT. However 
you need a separate IGBT and diode to carry the negative half-cycles. The 
overall losses are roughly 6 times more than if you had just got the two 
IGBTs and put them in parallel. IGBT bricks wouldn't avoid this problem.

Of course you could just allow it to kick back into the primary, and use a 
different kind of charging circuit that wouldn't be affected. It could be 
argued that good streamer/arc loading would drain most of the power from 
the resonator before it had a chance to kick back. This is the approach 
that I would take. In theory. In practice I have many other things to do, 
like finish my PhD thesis, find a job that doesn't suck, replace my cracked 
bike frame, and hit the trails :)

>Can you first notch quench your 2-coil OLTC
>configuration with K=0.2?

Yes. The scope trace is on this page:

http://www.scopeboy-dot-com/t3fnq.html

Steve C.