Vibroacoustic Characterization of a Permanent Magnet Synchronous Motor Powertrain for Electric Vehicles

The vibroacoustic characterization of an electric powertrain which consists of a permanent magnet synchronous motor and a gearbox for electric vehicles is analyzed in this paper. First, the vibroacoustic origins of the electric powertrain are investigated. The influence of current harmonics on electromagnetic force harmonics is presented. The spatial distribution of electromagnetic force exerting on stator inner surfaces is investigated by a two-dimensional magnetic transient solver. The spectrum of gear meshing force is then presented. After that, the vibration response of the electric powertrain system is predicted by a mode super-position method, based on which the acoustic noise of the electric powertrain is obtained using a direct boundary element method. Furthermore, the influence of electromagnetic force harmonics and gearbox on the vibroacoustic behavior of the electric powertrain is analyzed. To verify the calculating results, a vibroacoustic test is conducted in a semi-anechoic room and the results show that both electromagnetic forces and gear meshing forces contribute to a considerable proportion of the vibroacoustic behavior due to the integrated structure.