Re: [TCML] SSTC full bridge control system question

[Michael Twieg <mdt24@xxxxxxxx>]

That was a fascinating read Antonio.  I was able to replicate your
results accurately, even in my zero-crossing control model.  I didn't
think that complete beating in the signals was possible with
zero-crossing switching, since the beating should require a reversal
of phase.  In my previous simulations, the system was always excited
to the primary resonant frequencies, and never the "middle" frequency
as in you explanation.  Would this be because my own attempts didn't
meat your criteria for the spacings/ratios between the resonant and
middle frequencies?  I'm still a little cloudy on what you mean by
"odd" and "double odd" differences.

Many thanks,
-Mike

On Sun, May 2, 2010 at 4:40 PM, Antonio Carlos M. de Queiroz
<acmdq@xxxxxxxxxx> wrote:
> Michael Twieg wrote:
>>
>> Hello, this is my first post, please be kind,
>> I'm working with a team of engineers to build a large solid state musical
>> tesla coil, and my task in to project is to build control and telemetry
>> hardware.  We've chosen a full bridge design, a two coil configuration
>> (flat
>> spiral primary), and we're using an interrupter based loosely on steve
>> ward's design to control its switching.  Like his, it senses primary
>> current
>> and switches on zero crossing.  I've built the hardware and verified that
>> it
>> works in small scale testing...
>
> As Steve already said, the best tuning is the one that produces complete, or
> almost complete notches
> in the primary current (and capacitor voltage). At the notches all the
> energy in the system is in the
> secondary capacitance. This tuning is achieved, ignoring streamer loading,
> with a tuning exactly between
> the two resonances, if the system is designed for this. It is possible to
> obtain greater secondary voltage,
> but at the expense of much higher input current, as you probably noticed. If
> you have a certain
> maximum input current and a given load capacitance, the system can always be
> designed to operate in
> this "notched" way making optimum use of the current and with natural zero
> current switching. I have
> more detalis about this here:
> http://www.coe.ufrj.br/~acmq/tesla/drsstc.html
>
> Antonio Carlos M. de Queiroz
>
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