Characterization Of Electromagnetic Vibration And Noise In Interior Permanent Magnet Synchronous Motor For Passenger Vehicle

As one of the core components of modern passenger vehicles,interior permanent magnet synchronous motor(IPMSM)gradually develops towards high power density,wide speed range,large overload capacity and light weight,which makes the magnetic load of the motor enhanced and the stiffness decreased,and causes the electromagnetic vibration and noise of the motor become increasingly prominent.However,the high-frequency electromagnetic vibration and noise will undoubtedly reduce the driving comfort of electric vehicles.Therefore,it is essential to reveal why the electromagnetic vibration and noise of the IPMSM happen in the actual application.A 30 k W IPMSM for passenger vehicles to be discussed,and electromagnetic performance,structural modal characteristics,electromagnetic vibration and noise characteristics of the motor will be explored in this dissertation.Firstly,combined with the analytical model of permanent magnet synchronous motors(PMSM),the influence of stator slot and rotor salient structure on the air gap magnetic field is considered with relative permeability function.Then,the expression of radial electromagnetic force wave is derived,and the spatial order and time order of radial electromagnetic force wave are analyzed.On the other hand,based on the theory of vibration mechanics,the precondition for electromagnetic vibration and noise of motor are analyzed,that is,the "order" and "frequency" of electromagnetic force wave should keep consistent with that of motor structure modes.The main factors affecting the structural mode of motor are pointed out,and the relationship between vibration and noise is explained with the sound field governing equations.Secondly,according to the performance requirements of the motor for passenger vehicles,a few structure sizes used to satisfy the main performance criteria are determined,and the electromagnetic characteristics of the motor under no-load and load are calculated with the finite element method(FEA).The radial electromagnetic force wave and its time-space spectrum distribution characteristics at no-load and peak speed operation are analyzed.Then,the frequency spectrum distribution of the air gap radial electromagnetic force is compared under the two excitation of sinusoidal and space vector pulse width modulation(SVPWM),and the influence of the current harmonic introduced by motor controller on the air gap radial force wave is analyzed.Then,the characteristics for electromagnetic vibration and noise of motor is simulated based on the multi-physics field coupling simulation,and even more importantly,the modal experiment on the stator assembly,stator and shell assembly are carried out to verify the accuracy of the motor structure simulation model.Based on this,then simulate the electromagnetic vibration and noise of the motor under the excitation of sinusoidal current and SVPWM current respectively,and compare the influence of time harmonic of current on it.Finally,the prototype is manufactured and an experimental test platform for electromagnetic performance and vibration characteristics of the prototype is built.The no-load back electromotive force(EMF),torque or power with speed external characteristics of the prototype and the current waveform in a wide speed range were measured,which are compared with the simulation calculation results to verify the accuracy of electromagnetic performance simulation.At the same time,the vibration characteristics of the motor in a wide speed range are tested,the vibration acceleration test of the motor with different carrier frequency is carried out,and the results of simulation and experimental test are compared.