I'm seeing some unexpected behaviour and I'm not sure what's causing it.

I'm charging up 50V into a boost converter and then when discharging it using a thyristor, there is no issue here. When attempting to do the same with an IGBT, i.e. thyristor disconnected and IGBT connected, the boost converter has difficulty charging up to 50V. In fact it will only charge to half of that.

Exactly what could be the difference between having a thyristor in the off position connected as an output path for a capacitor bank and an IGBT in the off position connected as an output path for a capacitor bank?

The only thing I can imagine is that the IGBT is facilitating current leakage out of the capacitor even while the IGBT is off, but what would be causing this?

 

Schematic would be helpful.

Regards, Dana.

 

Are you sure the gate on the IGBT is at emitter voltage -could it be floating up due to leakage?

 

Except without the diode.

I'm replacing the thyristor with an igbt and getting this problem.

 

Schematic would be helpful.

Regards, Dana.

There's a schematic. The left side isn't fleshed out since it's a boost converter circuit but basically this is it.