Determination of Vehicle Interior Noise due to Electric Motor

This paper introduces an approach that uses a statistical energy analysis (SEA) method for prediction of noise in the vehicle cabin from an electric motor sound source placed in the engine compartment. The study integrates three different physics, namely, electromagnetics, harmonics, and acoustics. A 2004 Prius permanent magnet synchronous motor with an interior permanent magnet was used for performing the integrated CAE analysis, as the motor’s design details were readily available. The Maxwell forces on the stator teeth were first calculated by an electromagnetic software package. These forces were then mapped into a finite element model of the motor stator to predict the velocity profiles on the stator frame. Velocity profiles were considered as boundary conditions to calculate sound pressure levels and the equivalent radiated sound power level in the acoustic environment. The calculated sound power was used as an input sound source to perform SEA simulation to determine sound pressure level at the driver’s right ear in the passenger compartment. A sensitivity analysis of the motor design was performed on the sound power level generation and the sound noise level at the driver’s right ear in the passenger component. It was found that the air gap of the motor created significant effects on the radiated sound power.