Motor Electromagnetic Noise Prediction Research Of Pure Electric Car Based On The Hybrid-test Model

With the demand of energy conservation and emissions reduction, electric cars havebecome an important trend of the development of the auto industry. Pure electric cars’ noiseis much lower than traditional internal combustion engine car, but pure electric cars havetoo much high frequency noise that brings to the driving personnel discomfort. Motorelectromagnetic noise is one of the main sources of high frequency noise inside the car. Inthis paper, a domestic pure electric cars and drive motor is our research object, we willpredict the motor electromagnetic noise radiation sound field and motor electromagneticnoise in the car.In this paper, the pure electric cars drive motor that we studied is permanent magnetsynchronous motor. We established a complete three-dimensional motor structure model,meshed and defined the attribute of materials and constraints according to the actualinstallation condition of motor in the pure electric car. Based on the commercial softwareNastran, the natural frequency and modal vibration mode of the drive motor are calculated.The electromagnetic force which calculated by JMAG software is loaded into stator androtor of the motor structure finite element model. The vibration response (electromagneticvibration acceleration) on the surface of the motor is calculated by the modal superpositionmethod. Comparing the simulation results of electromagnetic vibration acceleration andvibration acceleration on the surface of motor measured by experiment, they have a goodagreement on the frequency of electromagnetic force.For calculating the electromagnetic noise of the motor and study the effects ofelectromagnetic vibration on the noise distribution, the paper establishes theboundary-element model to calculate the motor electromagnetic noise. The motorelectromagnetic vibration acceleration as the boundary condition is loaded on theboundary-element model, and defining the distribution of sites according to ISO standardsand then using the multi-pole boundary-element method to calculate the Radiation sound field of motor electromagnetic noise.This paper builds up the hybrid-test model by combining electromagnetic vibrationacceleration are obtained by simulation and air transfer function are obtained byexperimental measurement, and predicts the motor electromagnetic noise in the car by LMStest lab, and compares it with the target point noise inside the car by experiment measured,they have a good agreement on the electromagnetic noise frequency that further confirmedthe motor electromagnetic noise is one of the most important high frequency noise sourcesinside the car. Through the transfer path contribution analysis, we can predict the surfaceregion of motor and transfer path that have a great contribution to the motor electromagneticnoise inside the car, and provides a guidance to reduce high frequency noise inside the pureelectric cars.