No-Load Magnetic Field Calculation of Eccentric Pole Permanent Magnet Motor Based on Equivalent Magnetic Network Method

In this paper, on the basis of flux tube concept of the equivalent magnetic network (EMN) method, considering the geometric shape of the eccentric pole and the parallel magnetization, a 9kW surface-mounted eccentric pole permanent magnet synchronous motor (PMSM) is equivalently divided into a network of several flux tubes and magnetic sources. For the special structure of the eccentric pole motor, the magnet pole is divided into blocks. The EMN model is established and solved, the magnetic potential and the magnetic flux of subdivision units are obtained. On the basis of the EMN model, the air-gap flux density and no-load back EMF are calculated. The results calculated by the EMN model are compared with FEA model to verify the correctness of the analytical method. The results show that the EMN method can save analysis time compared with the FEA method on the premise of ensuring certain accuracy, which provides an effective analysis for the optimization design of eccentric pole PMSMs.