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Re: Terry's DRSSTC actually hooked to a coil now >:-))



Original poster: Terry Fritz <teslalist@xxxxxxxxxxxxxxxxxxxxxxx>

Hi Antonio and Steve,

It was fairly difficult to tune right to a "bad spot". As MicroSim predicted, the tuning is very precise... But end the end I was just tuning the secondary by moving my hand from 6 feet away and I could get some nasties:

http://hot-streamer.com/temp/DRSSTC-ModeSwitch-01.gif

http://hot-streamer.com/temp/DRSSTC-ModeSwitch-02.gif

http://hot-streamer.com/temp/DRSSTC-ModeSwitch-03.gif

The driver circuit is sort of "lazy" and does not want to respond to little glitches at all. The mode transitions also seem to "tune out" a bit since the cross overs are at sort of an unstable place. It is not easy to get "good examples". But the DRSSTC is very stable and repeatable so with a little trying I got these.

There is one silver lining though. Look at the current when the false trips occur. It is always near zero since the lockouts will not let it be anywhere else. So even if messy things do go on, they are limited to near zero current areas.

But with a VCO or PLL, goodness knows... I wonder if the PLL and a circuit like mine could be combined to get the best of both worlds...

Steve Ward reports tonight that he had good results just tuning a isolated oscillator and letting it all just fly. But I think his IGBTs could easily handle the double current worst cases too ;-))

I have noted tonight that my crossover dead time seems to be gone. Not sure if last night's experiments damaged something or if something is just tuned a little differently now... I rechecked that I put the caps and all back in right 4 times now... It could be a number of things... I'll play with it and see if I can figure it out. Seems to run fine so it can't be too serious :o)))

Someone should come up with an "official name" (ON) for these mode changes and these effects. They will be a part of DRSSTCs forever. Better save these E-mails to for when the question comes up 10,000 times in the future ;-))))

Thanks for everyone's help in explaining this all to me!!! It turned out to be a very cool thing I never knew about!!

Cheers,

        Terry


At 06:19 PM 2/2/2005, you wrote:
Tesla list wrote:

Original poster: Terry Fritz <teslalist@xxxxxxxxxxxxxxxxxxxxxxx>

I played with MicroSim and found that if I increase the primary inductance about 7uH I should be able to get this cool waveform:
http://hot-streamer.com/temp/NightmareWave.gif
This looks as excitation between the two resonances (the current
rises, then returns to zero), with the polarity of the driver
inverting when the energy tries to return to the power supply.
The reversal pumps more energy into the system in at each beat
of the primary current. The output voltage rises too.

Antonio Carlos M. de Queiroz