High voltage switch using IGBTs

david00001 · 2005-11-30T23:58:33+00:00

Hello folks,I plan to use 2 semikron SKHI 23/12 boards to control 4 half bridge1200V 200A Toshiba IGBTs. I want to use them as a high voltage- highcurent switch (3000 - 5000 volts, 150 amps...low duty cycle ..50usecpulses at 50 hertz) for some experiments I want to do.I am theorising that I should be able to connect them in series fromlow side emitter to topside collector and get a switch that can copewith transients of up to 9600 (8 x 1200) volts. I want to get thepulses as square as possible (especially the front edge). I plan tostatic balance the voltages with resistors ( I have some 15KV 100M wirewound resistors...) connected across the load contacts of the halfbridges. I know nothing about snubbers but I intend to learn...any goodinfo out there?I was hoping that those with experience in these matters might be ableto point out any flaws or give me any helpful suggestions they mayhave. What would be the best way to current limit this? The currentwill be passing through a non inductive load and some heavy diodes toground. The diodes are to stop any reverse bounce of current as I wantpurely DC pulses if possible. I am collecting parts at present. I have the IGBTs and the SKHI 23s. Iplan to build some heavy capacitors for the power supply. (I have alarge roll of 23 micron mylar :D)thanksDave

Nov 30, 2005 23 Replies

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david00001 20 years ago

LOL , you know what I mean :D. He suppressed any oscillation surges, I don't know how, hence my experimentation. cheers David

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david00001 20 years ago

Tim, thanks for that, I'll try it. David

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Tim Williams 20 years ago

Connect some twisted pair (rated for the voltage) across the HV resistor stack.

You might take TV 2nd anode wires (usually rated 40KV), tape two together to get some mutual capacitance, insulate the cut ends and connect the other ends across the resistors. Cut to length to adjust capacitance.

You might also do an air variable, if you don't mind an inch wide gap somewhere.

Tim

-- Deep Fryer: a very philosophical monk. Website:

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Terry Given 20 years ago

best not to think about how you can have pulsed DC sans AC :)

Quick, someone exhume Monsieur Fourier, and slap him silly.

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