Torque ripple reduction in the flux reversal motor by rotor pole shaping and stator excitation

This paper presents the result of the two-dimensional finite element analysis on the effects of rotor pole arc variation and number of teeth per rotor pole with different teeth depths and stator excitation pattern on various performance parameters like cogging torque, developed torque, harmonic torques, torque ripple and phase inductance for an 6/8, three phase flux reversal motor. A novel excitation pattern of exciting each phase for one step with positive and negative excitation in one rotor pole pitch resulting into higher torque per ampere is presented. Three teeth per rotor pole with the teeth height of 2.5% of the pole height reduces the torque ripple by 37.31% with the average torque reduction of just 5.36%.