[MPaulHolmes]

Holy cow! A regular old dual IGBT is enough for a boost converter that can do regen! I bought a 200amp 300uH inductor from Mouser a couple years ago that I could use in testing. It's not THAT heavy (it's my brother). I mean, it's ridiculously heavy, but not as just another component in a big fat car. Hmm... If you want to keep it as a separate object from the AC controller, I guess you would just need to tell the boost converter to switch to buck mode (switch connected to ground OFF, switch with the diode turned ON 100%). Then, the AC controller could command the current for regen.

I need to double-check this, but I'm pretty sure.

You don't need an input capacitor to the boost converter. Just the big fat inductor. Then, a fancy ring capacitor on the output... Maybe if the boost converter & inverter shared that cap, it would be fine. But it would need to be the same package so as to minimize stray inductance.