Research On Electromagnetic Noise And Vibration Of Interior Permanent Magnet Synchronous Motor For Electric Vehicles

With the development of electric vehicle industry,interior permanent magnet synchronous motor(IPMSM)has become one of the main choices for electric vehicle drive motor due to its high power density and wide speed range.The noise and vibration of drive motor are directly related to the comfort and reliability of electric vehicles,so the research on the electromagnetic vibration and noise of interior permanent magnet synchronous motor is of great significance and application value.In this paper,the electromagnetic performance,modal characteristics,electromagnetic vibration and noise of a 42 kw interior permanent magnet synchronous motor for electric vehicles are studied.Firstly,according to the relevant electromagnetic field theory,the analytical expressions of the air gap magnetic field and the radial electromagnetic force wave of the permanent magnet synchronous motor are derived by using the analytical method,and the spatial order and frequency of the force wave are analyzed.Based on the theory of vibration mechanics,the structure mode of motor and the mechanical structure vibration of motor based on mode superposition method are analyzed.The relationship between electromagnetic vibration and noise of motor is analyzed by using sound radiation theory.Secondly,the electromagnetic structure vibration coupling simulation model is established,and the simulation research in multi physical field is carried out.In the electromagnetic field finite element simulation,the air gap magnetic field distribution and radial force wave space-time spectrum distribution characteristics of the motor under no-load and load conditions are analyzed;in the structural finite element simulation,the modal vibration mode and natural frequency of the motor stator core and the whole machine are analyzed;in the noise and vibration simulation,the shell vibration response of the motor at the rated speed and the equivalent radiated sound power of wide speed range operating,and the total sound power radiated in space under A weighting are analyzed.Then,according to the finite element simulation,the influence of structural parameters on no-load air gap magnetic field of the motor is analyzed according to the0-order main electromagnetic exciting force wave of the motor,and the methods of adjusting stator slot width and adopting eccentric air gap are proposed to suppress the noise and vibration of the motor.The influence of low frequency harmonic current on noise and vibration of motor is analyzed.The results show that the influence of low frequency harmonic current on electromagnetic radial force is determined by its phaseFinally,the noise and vibration experiments of the prototype are carried out.The accuracy of structural modal simulation is verified by modal benchmarking experiment,and the noise and vibration characteristics of the motor during wide speed range are tested and compared with these of finite element simulation.