I have built the following circuit as a static AC switch (no high frequency switching).
The IGBT is a dual common-emitter module (https://www.infineon.com/dgdl/Infineon-FF300R12KT3_E-DS-v02_00-en_de.pdf?fileId=db3a304313b8b5a60113b981ab7e0010) I am using a MGJ6 15V/10V DC-DC converter (https://www.mouser.com/datasheet/2/281/kdc_mgj6scdc-1019175.pdf) to power my gate driver, which is a 1EDC60I12AH (https://www.mouser.com/datasheet/2/196/Infineon-1EDCxxI12AH-DataSheet-v02_00-EN-1272149.pdf). 100nF decoupling caps on both modules and a 20μF bulk cap on each DC-DC output. 5 and 20R resistors on sink and source driver outputs respectively. 1μF-47R snubber network. I tried following the recommended setup using a bipolar supply for the gate driver the datasheet recommended.
Also, in case it isn't clear, the common emitter is tied to 0V coming out of the MGJ6.
The issue is, the IGBT is never in the off state. When I first built the circuit and measured it, I was getting a Drain-Drain voltage of about 80VAC. So it was sort of half-off? When I measured it again later, it didn't seem to want to turn off at all. I was getting about 1VAC across Drain-Drain, which would indicate to me that it was still completely in saturation. At the time I measure this value, the Gate-Emitter voltage (VGE) is -8V! When I switch them "on", VGE becomes +16V. Same voltage drop across Drain-Drain. I cannot figure out why I cannot get them to turn off.
A theory--am I destroying the IGBT module somehow? Am I not providing the gate with enough current? Do I need different cap values on the 15V and -8V rails? Any help would be appreciated. I'm rather stumped.