Study And Control Of Internal Vibration Of Pure Electric Vehicle Under Initial Conditions

With the country’s strong support for the pure electric vehicle industry,the market for new energy vehicles has increased dramatically.The structure of new energy vehicles is quite different from that of traditional vehicles,and the most obvious one is the power drive system.Therefore,most of the problems brought by new energy vehicles are different from that of traditional vehicles.The common problems include electromagnetic vibration and noise of the driving motor,vibration and noise of the driving system,tangential and radial electromagnetic waves generated by the driving motor at high speed,and high-frequency electromagnetic noise.This paper focuses on a pure electric SUV in the development stage,and studies the low-frequency vibration problem of the steering wheel in the starting condition.Firstly,the inverse matrix method based on the improved BP algorithm is used to identify the contribution of load excitation source and path.Then combined with the maximum torque ratio current(MTPA)control and space vector(SVPWM)modulation strategy to reduce the vibration of the excitation source.Finally,the path frequency response function(FRF)is optimized by using the non-dominant sorting algorithm with elite strategy.The specific work content is as follows:Firstly,the theoretical knowledge and analysis process of the transfer path analysis method are introduced,and the inverse matrix method in the identification method of many load excitation sources is discussed.The ill-posed problem of matrix inversion is discussed in detail,and the ill-posed problem is improved by the improved BP algorithm.Secondly,the vibration response test of pure electric vehicles under starting conditions is taken as the target.The vibration acceleration of the steering wheel,the output torque and speed of the driving motor,and the vibration acceleration of the active and passive side of the suspension system are collected.In combination with signal characteristic test analysis and transmission path analysis(TPA),processing and analysis are carried out on the experimental data collected in the working condition.Finally,the position where the load excitation point and path contribution are the largest is identified.Then the mathematical model and the torque equation of the permanent magnet synchronous drive motor in the d/q two-phase coordinate system are established.The vibration of steering wheel is caused by harmonic input current of driving motor.Therefore,two control methods of the motor system are given: the active control system composed of feedforward and feedback compensation control and MTPA control,and the SVPWM vector modulation strategy is explained in detail.Then,in Matlab/Simulink module,the power transmission system model was established for simulation,and the vehicle test was carried out.It was found from the test results that the steering wheel vibration under starting conditions was improved.Finally optimize the suspension system,suspension system to establish permanent magnet synchronous motor drive the though laser ` s Equation.Then we use NSGA-2,a non-dominant sorting algorithm with elite strategy.To optimize and improve the multi-reference and multi-objective problems composed of 3 mounting stiffness and 9 frequency response functions(FRF)of the powertrain.From the improved test data,it can be found that the effect is better.Through the research and analysis in this paper,it is found that the steering wheel vibration and path FRF in the car are improved.This result provides guidance and reference for NVH performance development of new energy vehicles.