Design consideration to achieve wide-speed-range operation in a switched reluctance motor

This article introduces a concept to extend the base speed of a switched reluctance motor (SRM) from the perspective of the motor's design. Conventionally, designs prioritize a high saliency of SRM in order to produce more torque with the same current. However, the speed range is limited in the conventional design. The back EMF is the key factor that restricts the speed of the SRM from further increasing due to its strong reaction to the phase terminal voltage applied, which is especially severe at high-speed operation. Therefore, in this article, the design of an SRM with a lower inductance slope is proposed. The reduction of the motor's saliency in the proposed idea can effectively diminish the back EMF; thus an extended base speed and wider constant torque range can be achieved. Comparative simulation results from the conventionally designed motor and the motor designed by the proposed idea are given, which demonstrate that the base speed is enhanced and the current control can be maintained at a higher speed in the proposed idea.