Running two coils from one IGBT you are doubling the current and the IGBT may not be big enough. Then there is the transient voltage, the IGBT can cope with up to around 450v transient but with two coils generating 400v the actual voltage may be more than the IGBT can carry, i am not sure. However, I was
TOLD by one of the developers that you
SHOULD NOT double up the coils on on IGBT.
There is provision for 8 IGTBs, and you would need 6. How many other things you are driving
need an IGBT
Also, personaly I would leave the IGBTs onboard and use those to drive the drivers built into the coils thus protecting the driver chips in the ECU. Its getting a bit long winded with the processor driving the driver chip driving the IGBT, driving the driver in the coil