Influence of rotor eccentricity on electromagnetic vibration and noise in permanent magnet synchronous motor with different slot-pole combinations

Abstract

Rotor eccentricity (RE) is a common fault in permanent magnet synchronous motor (PMSM). In this paper, a multiphysics model is proposed to investigate the variation of electromagnetic vibration and noise due to two types of RE including static eccentricity (SE) and dynamic eccentricity (DE). Maxwell stress tensor is first employed to derive the spatial and temporal changes of electromagnetic force from eccentricity, which are validated by 2-D decomposing of radial force calculated by a finite element (FE) model. Then, based on the proposed multiphysics model, the electromagnetic vibration and noise considering RE with different eccentricity levels and types is calculated. The vibration and noise changes with eccentricity are all explained by the force harmonics induced by eccentricity. It is concluded that the influence of RE on vibration and noise is closely related to the slot-pole combination. The vibration and noise in PMSM with higher space order of force is more sensitive to RE. It is also found that, due to the low space order force induced by RE, vibration and noise peaks would transfer to the frequency band close to lower modal frequencies.