Analysis Of Electromagnetic Vibration Noise Of Permanent Magnet Synchronous Motor Based On Field-circuit Coupling

With the development of electric vehicles,permanent magnet synchronous motors have received more and more attention as one of its important driving components.The vibration and noise of the drive motor will seriously affect the comfort of the occupants.Therefore,in order to improve the competitiveness of the product,when designing and developing the permanent magnet motor,the motor team needs to consider not only whether the electrical performance of the drive motor meets the requirements,but also the NVH of the drive motor.performance.At present,the finite element method is generally used to calculate the noise of permanent magnet synchronous motors.The excitation used in this method is a sine wave current,which cannot simulate the electromagnetic noise caused by high-frequency harmonics when the motor controller is powered.Electromagnetic vibration and noise model of permanent magnet synchronous motor.Use this model to predict the electromagnetic noise of permanent magnet synchronous motor when the motor controller is powered.The main research content is divided into the following parts:Firstly,the composition of the control system of permanent magnet synchronous motor is described,and the structural principle,mathematical model,vector control principle and field-circuit coupling equations of permanent magnet synchronous motor are introduced in detail.Secondly,the vector control model of permanent magnet synchronous motor,the finite element model of the electromagnetic field of the motor and the main circuit model are established separately.The model interface module combines the three to obtain the fieldcircuit coupling model of the control system of the permanent magnet synchronous motor.Dynamic and steady-state performance.By comparing with the simulation current waveform and frequency spectrum based on the Simulink permanent magnet synchronous motor control model,the field-circuit coupling simulation model of the permanent magnet synchronous motor control system can consider the current harmonics brought by the nonlinearity of the motor body and the controller.Then,the expressions of air gap magnetic field and radial electromagnetic force when sine wave power supply and motor controller power supply are derived.The main space modulus and radial electromagnetic force frequency generated by the motor under the two power supply modes are summarized.The electromagnetic field analysis model of the motor is established,and magnetic lines of flux distribution and the magnetic dense cloud image of the motor are obtained by simulation.Post-processing analysis of the simulation results yields the spatial distribution of the radial air-gap magnetic field and the tangential air-gap magnetic field.According to the Maxwell stress equation,the radial electromagnetic force on the surface of the stator teeth is extracted and its frequency,modulus distribution and amplitude are analyzed.A comparative analysis of the radial electromagnetic force spectrum generated by the field-circuit coupling method and the finite element method simulation shows that the spatial modulus distribution of the radial electromagnetic force generated by the two methods is consistent,and the amplitudes are small.The frequency distribution and amplitude of the radial electromagnetic force generated by the two methods within 0-8000 Hz are basically the same.The field-circuit coupling method in 8000-12000 Hz will generate high-frequency radial electromagnetic force near the switching frequency,which is powered by the motor controller.The analytical results of the radial electromagnetic force remain consistent.Finally,the free modal simulation analysis and modal experiment are carried out on the stator system.The modal test is carried out on the stator system by the force hammer method and compared with the simulation results.Taking the radial electromagnetic force generated by the motor under the field-circuit coupling method as the excitation,the electromagnetic vibration noise of the permanent magnet synchronous motor is calculated by the modal superposition method and the MATV noise radiation simulation method.By comparing the sound pressure level spectrum of simulation and noise experiments,the error of this model can be used to predict the vibration and noise of permanent magnet synchronous motors within an acceptable range.