Experimental Verification and Effects of Step Skewed Rotor Type IPMSM on Vibration and Noise

Radial force and tangential force, which deform stator core, are the main causes of vibration and noise. There are many methods to minimize such electro-magnetic exciting forces by designing of magnetic core shape. However, modification of rotor shape increases development cost of the motor. Therefore, step skewed rotor is applied to the design to reduce electro-magnetic exciting force so that both reduction of vibration and noise and cost-effectiveness of development can be achieved. In order to consider step skewed rotor in interior permanent magnet synchronous motor (IPMSM), 3-dimensional finite element analysis (FEA) is used to consider leakage flux in axial direction and overhang effect. Furthermore, deformation of stator core caused by exciting force is analyzed to explain the mechanism of reduction of vibration and noise by skewed rotor. Comparison between prototype and step skewed model is performed in terms of analysis of exciting force, deformation of stator and experimental result of vibration to verify the analysis method.