David Sharpe skrev:
I would also like to point out that it would be a serious stretch for someone in the TCML community to build a truly adjustable SS SG that could hold off these voltages. A SISG would retrigger I believe based on the dV/dT excursions when it is commanded off. Also based on your animation, it is not the dI/dT excursion that's so severe but the dV/dt when turning on (0 to -Vapplied peak in turn on time of 100ns -- 2 usec time regime). Steve Ward, Finn Hammer, Greg Leyh,other power electronics experts out there, prove me wrongRegards
David, Fine company you are placing me in.The SISG is not a quencher, in the sense that you can command it to quench. the gate voltage sort of fades away right slowly, and we have let it do so, since it worked fine that way: In it´s native application, a Tesla Tank Circuit, not much energy was left to produce heat at turn off, anyway. And most of us that have used it believe that a tesla coil should be allowed to ring out at it´s own leasure. I have no experience of magnifiers, so I cannot comment on that. A quenching timer could be implemented, though. I am not sure it would be a good idea, since it would defeat the voltage protection of the IGBT that the SIDAC`s would provide. (We would use TRISIL`s today, btw.)
Provided that there is no danger of overvolting the switches, we could force a quench, but that seems to be out of the question for a stack of IGBT`s, I`m afraid. The only real chance I see for a solid state switch is a high voltage IGBT, and since it will be a single element, there is no virtue in using the SISG topology, except as an overvoltage safety catch. A controller like Steve Conners OLTC controller would be a better alternative, I think.
So I guess your gut feeling is right. Cheers, Finn Hammer _______________________________________________ Tesla mailing list Tesla@xxxxxxxxxx http://www.pupman.com/mailman/listinfo/tesla