Re: OLTC - Primer

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

Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>

Hi Ted,

You have been looking close :-))

The switch in the schematic has the primary resistance hidden in its
definitions.  "Tonights" schematic has them more visible ;-))

http://hot-streamer-dot-com/temp/OLTC8-14-02.gif

If we have a 32kHz operating frequency with a 500nH primary, we can
calculate the Xz impedance as only 0.1 ohm!  The primary impedance must be
"extremely" low for the system to oscillate.  However, the IGBTs can do
2000 amps with 5 volts drop.  That is 0.0025 ohm (actually better (~0.001)
in a dynamic model case).  The 10 caps in parallel are 0.0004 ohm at 3.8nH!
 So it is up to the primary to be low loss too, and it's all done and
working ;-)  The primary sure "looks" like an inductive dead short :-))

BTW - I have been trying to get this model so it can be downloaded, but
some model redefinitions and such make it very hard to transport and have
work...  Many bugs in MicroSim 9.1...  Grrrrr...

Cheers,

	Terry


At 01:42 PM 8/15/2002 +1200, you wrote:
>Hi Terry et al
>
>Been looking at the computer model schematic.
>Wondered if it needed a low value for Rp to be added ?. Perhaps it would
>provide a sensitivity analysis of Rp to Vs.
>Best
>Ted L in NZ
>