Study on Cogging Torque Characteristics and Reduction Considering Iron Loss

This paper is designed to reduce cogging torque by applying a 3D finite element method. Step skew was applied to the rotor to reduce cogging torque. Cogging torque can be removed in theory, but not in practice. Even though design can reduce cogging torque, cogging torque exists as there are many harmonic components in the manufacturing process and the cogging torque waveform. Additionally, the waveform and magnitude of cogging torque can be altered by iron loss. Therefore, in this paper, the optimum number of step skew and the step angle are proposed to reduce cogging torque by analyzing the harmonic cogging torque waveform. In addition, the analysis result of cogging torque and the measurement result were analyzed. The cautions about the measurement of cogging torque have been studied. Finally, the validity of the paper was verified through evaluation.