Connect the opto coupler between the IGBT gate and the IGBT source.
I noticed that there exist isolating unregulated DC/DC converters with 15V or +-15V output. I am thinking this is similar to the battery solution except I can use a single 5V or 15V supply. I am not sure if each isolated output needs to be regulated, say with an LM7815, though.The only way I've seen it done is with multiple batteries. You may be able to do it with some clever inductive charging, though. We actually charge our IGBT driver batteries back up with an inverter through an inductive charging system. Maybe you could, instead, just charge a (large) cap via inductive charging to power your circuit?
Hmm... I suppose that's a good point. If you put your power through an isolated DC/DC supply, you should be able to have each supply, essentially, floating. Just make sure that your isolated DC/DC supply is rated for the voltage you're expecting on the IGBTs and, of course, give yourself some overhead. If you're expecting 500V on the IGBT, I'd recommend that your supplies be rated for at least 750V isolation -- 1kV would be better.I noticed that there exist isolating unregulated DC/DC converters with 15V or +-15V output. I am thinking this is similar to the battery solution except I can use a single 5V or 15V supply. I am not sure if each isolated output needs to be regulated, say with an LM7815, though.
by Jake Hertz
by Duane Benson