A numerical model for predicting vibration and acoustic noise of IPMSM

A numerical model to predict acoustic noise due to electromagnetic forces in interior permanent magnet synchronous motor (IPMSM) is presented and applied to a spoke-type ferrite magnet motor for electric vehicles. The methodology includes the calculation of radial magnetic forces applied on tooth surfaces to account for the effect of motor vibration on the noise. Fundamental and high order harmonics of the magnetic forces are then obtained via FFT process. A model was developed to predict sound pressure levels based on an indirect BEM solver. Actual sound pressure levels were measured to validate the model and the results showed that the model predictions agree well with the observations from the experiments.