Er, everybody switched to SiC MOSFETs, so... definitely not.
> The power-switch that controls "on" vs "off" needs to be incredibly efficient when you're shoving 200+ kW of energy through it!!
Even before SiC became economical, FETs were edging out IGBTs in most applications. The voltage drop across IGBTs is just too high.
In fact SiCs have worse on/off efficiency, but are still preferred because they can switch more quickly and in the end that makes them more efficient, overall.
> Its probably one of the most major sources of efficiency in the modern electric vehicle.
I would give that to the battery or the motors before the controller. Controller have been >97% efficient for ages and ages, but motors are another thing entirely and better computers, salient rotors and permanent magnets, and better characterization have led to bigger gains than the switching elements have seen.
Neither hold a candle to batteries though. The resistance of switches is <10 milliohms, and motor resistance isn't much higher. The resistance of a 400 volt, 250 Ah NiMH battery is around 180 milliohms. The same battery built with venerable NCR18650Bs (original model S) is 68 milliohms. That's a full 7x improvement, or an 86% reduction in loss, and by far the biggest inefficiency besides aerodynamics and rolling friction.
