Improvement of hysteresis control in switched reluctance motor drives

Hysteresis control is commonly used in switched reluctance motor (SRM) drives, operating in the low speed region, for limiting the current to the desired value. Not much attention has been paid in the literature to the effect of the size of the hysteresis current band on the performance of the SRM drive. This paper analyses the effects of the size of the hysteresis band on the machine performance and presents a new improved hysteresis control to improve the drive efficiency for low speed operation of SRM. The size of the hysteresis band has significant effect on the switching losses, conduction losses, core losses and torque ripple. Theoretical analysis, aided by computer simulations are employed in this study to determine the optimal current band size for different speeds in the low speed operation of SRM. It is expected that implementation of this algorithm in high power SRM drives, operating at low speeds, will improve the overall drive efficiency to a significant extent