Rotor Surface Optimization of Interior Permanent Magnet Synchronous Motors to Reduce Both Rotor Core Loss and Torque Ripples

This article describes rotor shape optimization of interior permanent magnet synchronous motors to reduce both rotor core loss and torque ripples. The experimental verification by the prototype motor is also carried out to confirm the validity of the optimization. It is clarified that both the rotor core loss and the torque ripples under typical driving conditions can be significantly reduced by optimizing the rotor surface without considerable deteriorations of the other important characteristics. The mechanism of the design tradeoff for the torque ripples under different driving conditions is also clarified.