Prediction of Electromagnetic Vibration With Simulated Transfer Function for Interior Permanent Magnet Synchronous Motor

In recent years, the vibration and noise induced by electromagnetic excitation in interior permanent magnet synchronous motors (IPMSMs) used in electric vehicles have been a focus of interest. Accordingly, the mechanism and simulation technologies of the multi-physics field have been improved. However, identifying the root cause of vibration remains challenging. Hence, an efficient approach for predicting vibration performance suitable for the multi-objective optimization of the electromagnetic concept of IPMSM must be formulated. The study results presented in this article are anticipated to resolve the foregoing challenges. First, the calculation formulae of air-gap excitation forces are obtained through theoretical derivation. The relationship between the radial forces and electromagnetic field harmonics of the stator, rotor, and air gap is established. Second, a simulated structure transfer function is proposed to predict vibration. This method is considered as a technique for model order reduction; its theory is elaborated in this article. Compared with the direct coupled field simulation, the foregoing method not only enables the capability of tracking the vibration order in IPMSM over a wide speed range but also reduces calculation effort. In this study, the stator resonance with a “breathing” mode in an eight-pole IPMSM with 48 stator slots is analyzed using the proposed method. Finally, the vibration predicted by the proposed method is verified by coupled-field simulation and experimental tests conducted on a prototype.