Extended-Speed-Range Low-Torque-Ripple Control for Unsaturated Switched Reluctance Motors

Switched reluctance motors (SRMs) feature a simple, inexpensive and robust structure making them potentially attractive, but when designed and operated in conventional way they suffer of large torque ripple, vibrations and noise. Machines featuring more than 3 phases can achieve better performances; in a previous paper, a control strategy was proposed permitting to drastically reduce torque ripple in 5-phase SRMs working in linear to mildly-saturated conditions. Nevertheless, the considered sinusoidal-pulse current waveforms are not the only able to implement such concept. In this paper, the extension of the speed range is also pursued as a target, defining an improved control strategy able to lever on the existing degree of freedom. Such new control strategy is investigated both analytically and by means of simulations, confirming the ability to extend significantly the speed range while preserving a low torque ripple.