Vibration And Noise Mechanism Analysis Of Electric Drive System Based On Multi-Body Dynamics

In order to cope with the global energy crisis and environmental pollution caused by the combustion of fossil energy and other non-renewable resources,China,as the world’s largest power generator and electricity user,is transforming and upgrading its automobile industry and actively developing new energy vehicles such as pure electric vehicles and hybrid electric vehicles.With pure electric vehicles as the representative,the pursuit of high power density,high integration of electric drive assembly device,at the same time,it brings the electric drive assembly NVH and reliability problems.Especially when the motor speed continues to rise,the frequency range of the motor frequency is becoming wider,and the resonance interval of the electric drive assembly is also increasing,which brings new challenges to the vibration and noise of the electric drive assembly.In order to improve the vibration and noise characteristics of the electric drive assembly,this paper has carried out research on the vibration and noise mechanism of the electric drive assembly,the electromagnetic force and magnetic field analysis of the permanent magnet synchronous motor,the multi-body dynamic electric drive assembly model,and the assembly vibration and noise bench test.The main research contents are as follows:(1)Construction of a simulation model of the electromagnetic force of the air gap magnetic field of a permanent magnet synchronous motor.The electromagnetic noise generation mechanism of the permanent magnet drive motor for vehicles is described,the space-time characteristics of the radial electromagnetic force of the air gap magnetic field are theoretically analyzed,the electromagnetic force simulation model of the permanent magnet synchronous motor is established,and the electromagnetic force excitation is obtained,which is consistent with the conclusion of the analytical theory.(2)Construction of multi-body dynamics model of electric drive assembly.Based on the finite element method,the finite element model of the electric drive assembly shell is established,and the calculated modal results of the assembly shell are obtained.The modal test of the electric drive assembly was carried out,and the calculated modal and experimental modal results were compared.The calculated modal results are consistent with the experimental modal results;based on the modal reduction method,an electromagnetically excited mechanically excited electric drive assembly multi-body dynamics model.(3)Vibration and noise analysis based on the multi-body dynamics model of the electric drive assembly.Analysis of gear speed fluctuation,gear transmission error,gear mesh stiffness,gear contact force,bearing load,and shell surface vibration speed,etc.It is verified that the electromagnetic excitation order and the gear meshing order are the main excitation orders for shell vibration.(4)Bench test of vibration and noise of electric drive assembly.Under constant torque transient conditions,the electric drive assembly vibration and noise bench test was carried out,and the relationship between the noise of each order and the total sound pressure level of the noise was compared,and the accuracy of the simulation model was indirectly verified;the simulation was compared.The vibration acceleration curve of the shell measuring point and the test measuring point verifies the accuracy of the model.