High-performance fully digital switched reluctance motor controller for vehicle propulsion

A high-performance fully digital controller has been designed for the control of a switched reluctance (SR) motor built for vehicle propulsion. The SR machine is specifically designed and built to have high density and low noise. The controller is designed to maximize the machine efficiency, the peak overload capability, and to minimize torque ripple at low speed. Lookup tables are stored in a digital-signal-processor-based controller to calculate the control parameters online. Three interpolations, between torque command, motor speed, and battery voltage, are performed to obtain the control parameters. Difficulties associated with the interpolation scheme are addressed. A high-bandwidth fully digital proportional plus integral current regulator has been designed for the control of the phase current. Advantages as well as the difficulties with the operation of the SR machine and its control have been addressed. A complete characterization of the controller for the entire torque-speed plane has been made through extensive dyno testing. Simulation and dyno test results have been presented to demonstrate the performance of this controller.