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Off Line - DRSSTC (OL-DRSSTC) - 3
Original poster: Terry Fritz <vardin@xxxxxxxxxxxxxxxxxxxxxxx>
I have been running a lot of models and now have this for the OL
-DRSSTC concept schematic:
I had to go to 60BPS instead of 120 BPS. I use the dead 1/2 cycle to
fire the coil so there is no incoming current to quickly recharge the
buss cap. Otherwise, once the coil is started, in never turns
off!! The waveforms look like this:
It should put out nice 60BPS bursts with 200kV peaks. Very long 2mS
duration. Power to the streamer is roughly 1080 watts. The resonant
charger gets the cap up to about 520VDC firing voltage with the line
and resistive losses (note that the inductor is 19mH now for
60Hz). It is a stunning 25 joules per bang!!!
The primary current is only 200 amps and everything else seems
generally easy without massive over loads. The 50 ohm resistors
across the gates reduce the gate voltage and act a bit like a dead
zone for the IGBT crossover.
The trigger circuit is pretty much out of the SIDAC data sheet...
The only concern is the 185uF buss cap. It will see about 22A
RMS! That would kill most single electrolytics so I will have to
look into that more.
By changing the SIDAC value, it should work off 120VAC or a variac at
lower test voltages too. Everything can be "fiddled with" as needed
to make adjustments or to get it to work.
So it is looking pretty good on paper and by computer. I think I
will order some parts...