Analytical Study and Experimental Verification of Electromagnetic Vibration Sources and Optimization of Rotor Skew in Surface-Mounted Permanent Magnet Synchronous Machines

In this article, a method for calculating the cogging torque and air-gap flux density of a surface-mounted permanent magnet synchronous machine (SPMSM) is studied. First, a simplified model of the SPMSM is presented for electromagnetic analysis, and the magnetic vector potential is derived using the governing equations based on Maxwell’s equations in a 2-D polar coordinate system. The air-gap flux density is derived using appropriate boundary conditions, and based on analytical solutions, the cogging torque was calculated. The analysis results derived through the proposed method, and the skew of the rotor, the skew angle, and segment that satisfy the optimal cogging torque of SPMSMs are derived. The accuracy of the proposed method is verified through a comparison with the analysis results with the finite element method (FEM).