Here is a basic diagram.
Essentially a bank of batteries supplies 600 Volts DC to the controller, that "chops" the DC up to look enough like 3 Phase AC (the type of AC used in factories) to run the 3 Phase AC Induction Motor.
The controller "*speed" signal comes from an accelerator pedal exactly the same as used on "fly by wire" cars like the Holden Astra, Audi, VW Golf etc. (*Actually the pedal controls torque.)
This diagram shows Lithium Iron Phosphate battery packs. There are 12 packs of 50Volts (shown in diagram as 48V) with 20AH capacity - that makes around a 12kW/h pack.
The motor is coupled directly to the tail-shaft. There is no clutch or gearbox.
Here is the proposed layout of these components in the car.
This will most likely change a bit once I have the existing Engine and gearbox out and can better measure where stuff can go. (Updated to show Lithium Batteries.)