Study of cogging torque in surface-mounted permanent magnet motors with energy method

Permanent magnet motors are extensively used in high-performance applications. However, in slotted permanent magnet motors, there exists cogging torque which may cause noise and vibration. In this paper, being based on energy method and Fourier expansion, the method for predicting cogging torque in permanent magnet motors with skewed rotors, is proposed. The predicted torque is in good agreement with the calculated results obtained from FEM. Finally, the effects of several factors on cogging torque are discussed, and some conclusions are drawn.