Torque Ripple and Cogging Torque Reduction Method of IPMSM Using Asymmetric Shoe of Stator and Notch in Stator

In this paper, a low-vibration motor design method for application to an electric compressor is described. Automotive parts used in automobiles are required to reduce motor vibration to satisfy NVH. Therefore, in this paper, we analyze the factors affecting the vibration and verify the vibration reduction effect of each factor through a numerical analysis method. The cogging torque is influenced by the magnetoresistance structure of the air gap, and the torque ripple is additionally affected by the shape of the air gap magnetic flux considering the armature reaction under the rated load operation. In this paper, the authors suggest a method to reduce cogging torque by applying a notch shape to the stator of a permanent magnet synchronous motor and reduce torque ripple by applying an asymmetric stator shoe shape. Finally, the authors propose optimal design having low cogging torque and torque ripple by magnetic saturation of the suggested shape are analyzed using Finite Element Analysis and the validity of the design method is verified by experimentation.