Torque ripple reduction of a synchronous reluctance motor for electric vehicle applications

Synchronous reluctance motor (SynRM) is a potential candidate for high starting torque requirements of traction drives. Any demagnetization risk is prevented since there is not any permanent magnet on the rotor or stator structure. On the other hand, the high rotor starting current problem, that is common in induction machines is ignored since there is not any winding on the rotor. Indeed, absence of permanent magnet in motor structure and its simplicity leads to lower finished cost in comparison with other competitors. Also high average torque and low ripple content is important in electrical drives employed in electric vehicle applications. High amount of torque ripple is one of the problems of SynRM, which is considered in many researches. In this paper, a new design of the SynRM is proposed in order to reduce the torque ripple while maintaining the average torque. For this purpose, auxiliary flux barriers in the rotor structure are employed that reduce the torque ripple significantly. Proposed design electromagnetic performance is simulated by finite element analysis. It is shown that the proposed design reduces torque ripple significantly without any reduction in average torque.