Modal analysis of the stator system of a permanent magnet synchronous motor with integer slot multi‐pole pair for electric vehicles

Abstract The 0‐order natural frequency resonance is the main cause of electromagnetic vibration noise in integer slot multi‐pole pair permanent magnet synchronous motors (PMSMs) for electric vehicles. To study this phenomenon, this study proposes a finite element (FE) model of the stator system based on a 48‐slot 8‐pole permanent magnet synchronous motor for electric vehicles. Based on this model, the effects of winding, frame end cover and temperature on the natural frequencies of a stator system are analysed by using the equivalent stiffness method (ESM). The simulation results show that the 0‐order natural frequency of the stator core system decreases after considering the winding varnished, and the 0‐order natural frequency is almost unaffected after considering the frame and end cover. However, the other natural frequencies increase in different degrees. In addition, the natural frequencies of the stator core decrease with the increase of temperature. The accuracy of the finite element model is verified by the modal experiment of the hammer method (HM).