Design and Control of a Propulsion Switched Reluctance Machine: Energy Utilization in Motoring Mode and Current Profiling in Generating Mode

Abstract

Electric motors constitute a critical component of an electric vehicle powertrain. Due to the absence of rare earth magnets, simple and robust construction, and inherent fault tolerance, Switched Reluctance Motors (SRMs) are a promising motor type to reduce the cost of electrified vehicle propulsion systems in the near future. However, due to their doubly salient structure, SRMs suffer from higher torque ripple as compared to other electric motor types. The aim of this thesis is to explore design and control techniques to improve the electromagnetic performance of SRM drives. First, an SRM drive has been designed for a 48 V hybrid electric vehicle application to replace a permanent magnet motor drive. The design challenges for wide-speed operation are addressed. Then, a methodology is proposed to evaluate the Energy Utilization Ratio (ER) in SRM drives. An experimental correlation is conducted to validate the ER computation methodology. Novel ER based control objectives are then proposed to improve the performance of SRM drives in the motoring mode. Besides, advanced current profiling based control is explored to reduce torque ripple in SRM drives in generating mode. An offline multi-objective optimization is conducted to obtain the optimal profile for the reference current. Finally, an experimental correlation is performed to validate the effectiveness of the proposed current profiling control scheme in the generating mode of operation.