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RE: DRSSTC design procedure - draft



Original poster: "Steve Conner" <steve.conner-at-optosci-dot-com> 

 >In just 5 cycles you have 21.7 Joules.
 >I recommend running some simulations to see if I didn't make a
 >mistake...

No, I can believe this :) The energies that can be delivered by the
"impedance matching" type of idea are quite spectacular. I've written a
parametric simulation in PSpice, and I'll plug your design and try
simulating it.

I was also working on a design of my own. My "empirical" design method (have
a guess based on the results of other peoples' experiments, then do 10
parametric simulations around that point, pick the best one, repeat)
"converged" on the following solution

Ca=0.2uF
La=42uH (it would also have worked with 36uH with minimum performance
change, however 33uH would shift the resonance to the upper pole)
k=0.315

This gives a "Ward mode" design that self-resonates at its lower resonant
frequency. The peak primary current was around 800-1000A depending on
streamer loading, and the total energy delivered is worryingly high. Over a
300 microsecond burst I found that it would deliver between 35 and 60J
depending on what assumptions I made for streamer length. However the toroid
voltage never rises above 600kV.

The primary current is considerably more than 600A, but I'm somewhat bound
to the 0.2uF primary capacitance (3 strings of 14 caps) I can't get less
without changing to 2 strings and I don't really want to do that.

If we just multiplied everything by 600/1000 we would get about the same 20J
as your method yielded. However it seems like (as you said) mine would need
more cycles at 600A to achieve this energy, in spite of having tighter
coupling?



My streamer loading model is:

Load capacitance 25pF per metre
Load resistance, 103000/(streamer length in metres)
I assume that a streamer of the final length suddenly appears when the
toroid reaches something like its breakout voltage.

Steve C.