Growing development of hybrid and fully electrical drives increases demand for accurate prediction of noise and vibration characteristic of electric and electronic components. This paper describes the numerical and experimental investigation of noise emission from PMSM electric machine as a one of the most important noise sources in electric vehicles.
Structural and air borne noise is measured on e-machine test rig and used for calibration and validation of the numerical model. The electro-magnetic field in PMSM is simulated using finite volume method. Electro-magnetic forces are applied as excitation to the 3D FE model of e-machine, mounded on test frame. Material properties are tuned using results from experimental modal analysis including identification of orthotropic characteristic of stator laminated core, assembled together with coil and end winding. Structural vibrations are calculated by modal frequency response analysis and applied as excitation in air borne noise simulation. Sound radiation is calculated using the wave based technique approach (WBT). Simulation and experimental results are compared in frequency range up to 6 kHz.
Developed simulation methodology can successfully predict the main noise sources from e-machine and results in good agreement in absolute values of sound pressure level. Stator 0th order diametrical mode, also called stator breathing mode, is identified as critical noise source, both in experiment and simulation.