An electric vehicle has
• a battery pack,
• a DC-DC converter that controls a 700 V DC bus from the pack,
• an inverter that delivers power to the main motor,
• the motor itself,
• a single fixed ratio gearset that delivers torque to the axle,
• and the vehicle itself.
One realization uses a three-phase permanent-magnet synchronous machine or PMSM (sometimes misleadingly called a "brushless DC" machine) adjusted to minimize reactive power. For a machine like this, the mechanical torque is proportional to the root mean square (rms) AC current. The motor voltage and frequency are linear functions of speed. At 1800 RPM, the motor requires 60 Hz. Given the gearset, the motor reaches 5400 RPM at maximum vehicle speed. When the vehicle is moving on level pavement, most of the work is done moving it through the air and accounting for rolling loss in the tires. This motor can deliver up to 150 N-m of torque and requires 250 A rms to produce it.
Evaluate the inverter requiretments control parameters and discuss how the control can put in place