Torque Ripple Suppression of Synchronous Reluctance Motors for Electric Vehicles Based on Rotor Improvement Design

This research takes an 18.5-kW automotive synchronous reluctance motor (SynRM) with four-layer "C"-type flux barrier rotor structure as the object and studies the influence of the end position of each layer of flux barrier on torque ripple. Comparing different flux barrier end deflection schemes, the effect of flux barrier end deflection on torque ripple is studied, and the effect of deflection angle on torque ripple and electromagnetic performance is obtained. The air-gap flux density waveforms before and after the flux barrier end deflection and the radial and tangential components of its harmonics are analyzed. The action mechanism of flux barrier deflection on torque ripple and electromagnetic performance is obtained by analyzing the phase relationship between tooth harmonics and fundamental waveforms. Besides, the deflection scheme of the flux barrier end with optimal performance is given. A SynRM performance improvement method through phase cancellation between the tooth harmonics and the fundamental wave is proposed. Finally, the experimental platform is built to verify the accuracy of the simulation calculation.