An efficient approach for cogging torque analysis of motors with three-dimensional flux distribution

This paper presents an efficient finite-element-based approach for a cogging torque analysis of pancake-type motors with inherent three-dimensional (3-D) flux distributions. For such cases, 3-D finite element analysis (FEA) that accounts for all 3-D effects is often required for convincing and reliable results. However, to obtain sufficient information, a considerable number of models may need to be created and result in a time-consuming analysis process using 3-D FEA. Therefore, a method named the "2-D Plus" is proposed to significantly improve the time efficiency of analysis based on two-dimensional techniques without sacrificing accuracy. Complete and smooth cogging torque waveforms can then be rapidly produced with the aid of only two extra 3-D models. The results from the presented technique agree well with that from 3-D simulations. The effectiveness of the proposed method in cogging torque analysis is thus verified.