A Review on Machine Topologies and Control Techniques for Low-Noise Switched Reluctance Motors in Electric Vehicle Applications

This paper presents a technical overview for low-noise switched reluctance motor (SRM) drives in electric vehicle (EV) applications. With ever-increasing concerns over environmental and cost issues associated with permanent magnet machines, there is a technical trend to utilize SRMs in some mass production markets. The SRM is gaining much interest for EVs due to its rare-earth-free characteristic and excellent performance. In spite of many advantages compared with conventional adjustable-speed drives, SRMs suffer from torque ripple and radial distortion (and thus noise and vibration) by their nature. Therefore, for high-performance vehicle applications, it is important and urgent to optimize the SRM system to overcome the drawbacks of the noise and vibration. In order to present clear solutions to the acoustic noise in SRMs, this paper starts by analyzing the mechanism of the radial vibration and torque ripples inherent in the motors, and then focuses on the state-of-the-art technologies to mitigate the radial force and torque ripples. It highlights two categories for low-noise SRMs, including the machine topology improvement and control strategy design for radial vibration mitigation and torque ripple reduction. Advanced technologies are reviewed, classified, and compared accordingly. In addition to these methodologies, the schemes that have been developed by authors are also presented and discussed. Finally, the research status on this topic is summarized and forecast research hotspots are presented. It is our intention that this paper provides the guidance on performance improvements for low-noise SRM drives in EV applications.