Low-cost single-switch variable-speed switched reluctance motor drive

This paper studies the effects of operating a single-switch converter for a variable-speed switched reluctance machine (SRM) drive without the large DC-link capacitor. The converter is intended for only low-cost, high-volume applications with low performance requirements. Detailed simulations are carried out to analyze the effects of having and removing the dc link capacitor in the converter. Efficiency and input power factor are compared for both converters. Simulation results show that removing the dc link capacitor results in a slight increase in efficiency and input power factor. However, absence of the dc link capacitor results in a slight increase in the magnitude and frequency content of the torque ripple. The studied drive, without the dc link capacitor, presents a viable variable speed motor drive alternative to traditional brush DC drives and universal motors in the low-cost market where cost is a major consideration. Examples of such applications are vacuum cleaners and low-power residential and industrial fans.