Noise Analysis And Experimental Study On Electric Vehicle Driven Motor

Electric vehicles and traditional cars differ in their power structure,so the motor driving system is one of the main sources of noise in the Electric vehicles.Due to the performance demand of high power density and high torque density in the automobile driven motor,the vibration and noise problem is becoming more and more prominent,which affects the comfort of driving.In this paper,the vibration and noise of the PMSM are studied in theory,experiment and simulation,which provide guidance for the analysis and optimization of vibration and noise of the electric car motors.Firstly,the type of noise source of electric vehicle driven motor is analyzed,the mechanism of electromagnetic noise which contributes to the overall noise of the driven motor is analyzed emphatically.and the order and eigenfrequency of the radial electromagnetic force of excitation source which produces electromagnetic vibration noise is deduced.Then introduces the identification method of vibration noise source of driven motor,the eigenfrequency of the mechanical noise and the electromagnetic noise source of the driven motor are analyzed.By this provides the theoretical basis for identifying the noise source of the motor by the order tracking method in the following vibration noise test.Secondly,the test method of vibration and noise of the driven motor is introduced.The LMS testing equipment is used to test the vibration and noise of the motor under steady-state and dynamic conditions by means of hemispherical method and using the test bench.Through the order and order contribution analysis,it is found that the electromagnetic noise of 8th order,24 th order and 48 th order of the driven motor and the high frequency electromagnetic noise caused by the current harmonics at the switching frequency have the greatest contribution to the overall noise sound pressure level of the motor,the pressure level of these noise are increases significantly as the load increases.However,the mechanical noise such as 1st order and 3.6th order contributes less to the sound pressure level of the overall motor noise and does not vary with the load.According to the identification method of the motor noise source in the theoretical analysis,the data after the test are analyzed,the specific sources of each order noise source are clarified,and the corresponding optimization suggestions are put forward.Finally,the electromagnetic-structural-acoustic multiphysics simulation analysis model of the motor is established for the electromagnetic noise source which contributes a lot to the sound pressure level of the motor noise.The two-dimensional magnetic field analysis,structural modal analysis,vibration response analysis and acoustic radiation analysis are carried out.By comparing the spectrum of vibration and noise test,the simulation reliability is verified.Through the electromagnetic-structural-acoustic multiphysics coupled simulation analysis of the motor,it is hoped that the electromagnetic vibration and noise of the motor can be accurately calculated and the design of the motor can be improved according to the simulation results in the design phase of the motor,hoping that we can try to control the electromagnetic noise of the motor to maintain a reasonable range.