A three-phase switched reluctance motor with two-phase excitation

A new excitation strategy for a switched reluctance motor (SRM) is described and tested. This scheme excites two phases of an SRM simultaneously, which is similar to the two-phase excitation method of a step motor. In this scheme, the torque is produced by mutual-inductance as well as by self-inductance. The abrupt change of a phase excitation produces mechanical stresses, resulting in torque ripple and noise. The acoustic noise is reduced through a sequential two-phase excitation. Noise reduction occurs because the scheme reduces abrupt changes in excitation levels by distributed, balanced excitation and freewheeling during commutation. The operational principle and a characteristic comparison to that of the conventional SRM show that this novel excitation scheme has some advantages, including torque ripple and noise reduction, as well as simple inverter topology.