Input shaft: LOCKED!

I'm now able to lock the two motors together and drive them against each other as a dyno. Did this briefly today and it worked nicely.

This is an important ability as it lets me tune the offset angle for different speed and torque settings. The IPM motors used in the transmission aren't like simple PMAC or BLDC motors. The IPM motors have a magnetic torque component and a reluctance torque component. This means that I can't just set the current vector to 90 degrees from the rotor magnetic field for maximum torque. I have to set it somewhere in between. I'm not really sure yet whether the optimum angle changes much with speed or torque, but that's what I can find out using this as a dyno.

The tuning process is this:

1. With one of the motors set to zero torque, set the other motor to a certain speed using a speed control loop (torque-producing current as the output).

2. Set a non-zero current setpoint for the first motor.

3. Sweep the offset angle through the expected range and plot the output of the speed control loop.

4. The angle which requires the highest torque from the speed control loop is the optimum angle for that speed and torque operating point.

5. Repeat that for a handful of strategically selected operating points and plot the relationships.

I'll start with a constant offset value for the unknown motor while tuning the other one. Once I've done that for both motors, I just have to put them in to a look-up table that is used while driving so I always have the optimum offset angle for every pedal position.

I'm really looking forward to getting this tuning done so that I can then write the code that implements "throttle" control of the motor torque. This will be fun because it's where I'll set up the framework for tuning the pedal feel. It will also be when I program the gear change required for MG2. That will be an interesting challenge.