Study on an Accurate Magnetic Network Model of Eccentric Magnet-Shaped Permanent Magnet Synchronous Motor

Permanent magnet synchronous motors (PMSMs) find extensive application across diverse domains thanks to their merits of high torque density and efficiency. An eccentric magnet-shaped design for a permanent magnet (PM) can effectively reduce the harmonic components in the air-gap magnetic field and suppress the torque ripple of the motor. The electromagnetic performance of the PMSMs is mostly analyzed by the finite element method (FEM), which requires a lot of time and computational resources. Therefore, a rapid optimization method for eccentric magnet-shaped PMSMs is proposed based on an accurate magnetic network model (MNM). The magnetic field characteristics of a six-phase eccentric magnet-shaped PMSM are analyzed based on the proposed model. Firstly, through an analysis of the motor’s magnetic circuit, an accurate MNM is established. Then, the established model is employed to achieve rapid and accurate calculation of the air-gap flux density (AGFD). Finally, the PM’s structure parameters are optimized. After the optimization by MNM, cogging torque (peak-to-peak) reduced from 2.2 N·m to 0.74 N·m; torque ripple (rated condition) from 0.14% to 0.05%; MNM time 20–30 s vs. FEM time 820 s. Compared with the experimental results, the MNM exhibits an error of 5.04% in EMF, 1.16% in output torque, and 0.67% in torque ripple. The effectiveness and accuracy of the MNM have been verified. The MNM can significantly shorten the design period while ensuring the calculation accuracy.