[MPaulHolmes]

Take your time deciding on a contactor. I just lost around 16 hours of work (over the last 2 days) on the PCB, because it got corrupted by DesignSpark! They are working on it, to see if it can be recovered. Most of the time was spent on the layout for the driver section. Well, I finally decided on a good driver section layout. They can't erase it from my mind! The schematic part is done now. So, it's just laying it out and routing it again, and hoping it doesn't happen again. I reinstalled designSpark. Hopefully that will help.

One nice thing is, if there is a short circuit condition on any of the igbt half-bridges, the offending hardware overcurrent will turn off all high and low side IGBTs in a couple microseconds. A separate desaturation detection circuit that's on each igbt (6 in total) will also turn off all igbts. Also, the software will stop making sine waves in less than a microsecond if any of those faults happen. If there's a failure of igbts so you get a dead short to ground, there should be a fuse that blows quickly. I can't think of a situation where regen will be a problem with the contactor. Especially, since the controller would have control of the contactor, and would know if regen was happening anyway, because of the current feedback.