The highest power density and best performing traction motot with the highest efficiencies at all speeds including high speeds is the axial flux PM AC synchronous motor. Second is the radial flux PM AC synchronous motor. Third is the Switched Reluctance DC motor without slip rings, brushes, without magnets and without windings on the rotor. The 4th and poorest performing motor of them all is the AC induction motor. However the two best ones are the most expensive even though every hybred car on production on earth uses the PM AC radial flux Synchronous electric motor. This is because they are much more efficient than the AC induction motor, they weigh less and they do not require as much cooling (The ac induction motor has a very hot rotor that cannpot be easily cooled).

The reason high performance cars like Tesla use AC induction motors is because for the power they need they can buy almost off the shelf AC motors and inverters from several sources for their low volumes. A PM AC machine must be designed from scratch.

If Tesla is successful to the point their volume goes to 50,000 cars per year they will have to switch to PM AC Synchronous to be competive or the competition will kill them.

The first GM electric vehicle the EV1 had a production run of 135 cars all leased. The traction motor was a modified version of a standard GE/AO Smith AC induction motor. The inverter was made by GM’s HUGHES division which was a flux vector AC drive. All production hybred vehicles made by GM currently us a permanent magnet synchronous brushless motor driven by a similar flux vector drive. They do not use an AC induction motor. The new Chevy VOLT will also have the same PM sychronous brushless motor.
One or two Chrysler care use this same PM brushless motor. This motor is made by REMY a former division of GM. The second generation Chevy Volt is reported to use a greatly enhanced PM sychronous brushless motor. (Probably two rather than one) There are no plans to use AC Induction motors in any production vehicles except the Tesla.

In fact, it appears that they just use pulsating DC from the batteries to drive the induction motor. As I understand it, these DC pulses are preceisly controlled by special software algorithms that optimize for power and efficiency.

So, if you want a whole house backup system, you’ll probably still need to spring $2K-$4K for a real sinusoidal DC to AC house type inverter, and then figure out some way to tap into the 300 volt DC batteries.