VP3-08 Advanced Harmonic Interaction Modeling for Fast and Accurate Cogging Torque Calculation in Permanent Magnet Machines
Creators: Litao Dai
Shuangxia Niu
Jian Gao
and Shoudao Huang
Publisher: name: IEEE
Year: 2025

I. Introduction Cogging torque is an inherent but undesirable characteristic of permanent magnet machines (PMMs). It introduces torque pulsations that can negatively impact control accuracy and smoothness. Accurately predicting cogging torque is essential for analyzing its characteristics and implementing targeted reduction methods [1]. Existing accurate cogging torque calculation models rely on numerical methods [2], which lack a direct correlation between field harmonics and cogging torque, making it challenging to directly reduce the cogging torque by design optimization. To overcome this limitation, this paper proposes an advanced cogging torque model based on the rules of field harmonic interaction in PMMs. This model offers significant advantages in terms of speed, accuracy, and a deeper understanding of the fundamental principles governing cogging torque. II. Results The proposed method involves analyzing individual field harmonics and directly calculating the results of harmonic interaction based on the cogging torque's action law. This approach eliminates the need for computing multiple transient fields and establishes a direct relationship between field harmonics and cogging torque. Figs. 1 and 2 depict a comparison of the prediction results between the harmonic interaction modeling (HIM) method and the finite element method (FEM) for two PMMs. The results demonstrate that the HIM method achieves excellent accuracy while significantly reducing the computation time required.References: [1] L. Dai, S. Niu, W. Zhang, J. Gao and S. Huang, "Harmonic Modeling and Ripple Suppression of Electromagnetic Torque in IPMSMs," in IEEE Transactions on Industrial Electronics, Early Access, doi: 10.1109/TIE.2024.3384614. [2] S. A. Saied, K. Abbaszadeh, A. Tenconi and S. Vaschetto, "New Approach to Cogging Torque Simulation Using Numerical Functions," IEEE Trans. Ind. Appl., vol. 50, no. 4, pp. 2420-2426, July-Aug. 2014, doi: 10.1109/TIA.2013.2293814.
I. Introduction Cogging torque is an inherent but undesirable characteristic of permanent magnet machines (PMMs). It introduces torque pulsations that can negatively impact control accuracy and smoothness. Accurately predicting cogging torque is essential for analyzing its characteristics and implementing targeted reduction methods [1]. Existing accurate cogging torque calculation models rely on numerical methods [2], which lack a direct correlation between field harmonics and cogging torque, making it challenging to directly reduce the cogging torque by design optimization. To overcome this limitation, this paper proposes an advanced cogging torque model based on the rules of field harmonic interaction in PMMs. This model offers significant advantages in terms of speed, accuracy, and a deeper understanding of the fundamental principles governing cogging torque. II. Results The proposed method involves analyzing individual field harmonics and directly calculating the results of harmonic interaction based on the cogging torque's action law. This approach eliminates the need for computing multiple transient fields and establishes a direct relationship between field harmonics and cogging torque. Figs. 1 and 2 depict a comparison of the prediction results between the harmonic interaction modeling (HIM) method and the finite element method (FEM) for two PMMs. The results demonstrate that the HIM method achieves excellent accuracy while significantly reducing the computation time required.References: [1] L. Dai, S. Niu, W. Zhang, J. Gao and S. Huang, "Harmonic Modeling and Ripple Suppression of Electromagnetic Torque in IPMSMs," in IEEE Transactions on Industrial Electronics, Early Access, doi: 10.1109/TIE.2024.3384614. [2] S. A. Saied, K. Abbaszadeh, A. Tenconi and S. Vaschetto, "New Approach to Cogging Torque Simulation Using Numerical Functions," IEEE Trans. Ind. Appl., vol. 50, no. 4, pp. 2420-2426, July-Aug. 2014, doi: 10.1109/TIA.2013.2293814.