Performance comparison of switched reluctance motor with sinusoidal and conventional excitation

Switched reluctance motors (SRMs) are popular due to their advantages of simple and robust construction, wide speed range, and fault tolerance. Commonly cited limitations of SRMs are acoustic noise and the need for a different inverter configuration. It has been reported that when the SRM phases are excited with sinusoidal bipolar currents, there is significant reduction in acoustic noise. Further, with this excitation scheme, the voltage source inverter (VSI) configuration commonly used for all AC drives can be used for this motor. Another advantage of sinusoidal excitation is that well established position sensor-less control schemes used for other AC machines can be used. This paper discusses a sinusoidally excited fractional HP switched reluctance motor (SRM) for use in appliances. It is found that the advantages mentioned above are achieved at the cost of other performance parameters. Simulation results comparing efficiency, inverter VA rating, width of constant power region and radial forces for sinusoidal and conventional excitation schemes are presented. Further, a prototype of the motor is fabricated, and experimental results are presented.