Analysis Of Dynamic Behavior Mechanism Of Electric Vehicle Powertrain Based On Nonlinear Dynamics Theory

Vibration and shock are important factors affecting the safe and stable operation of electric vehicle transmission system and the riding comfort of electric vehicle.Electric vehicles work in the environment of vibration and impact for a long time,such as vehicle start-stop,rapid acceleration,rapid deceleration and uneven road surface bump may cause the vibration or impact behavior of electric vehicle drive system.It is of great significance to analyze the dynamic behaviors such as vibration and impact of electric vehicle transmission system and explore the internal mechanism of its dynamic behaviors for realizing the inhibition of vibration and impact and improving the riding comfort of electric vehicles.Therefore,in this paper,pure electric vehicle transmission system as the research object,from the perspective of energy,the Lagrange method is used to establish the electromechanical coupling model of pure electric vehicle transmission system,to study the electromagnetic parameters on the resonance behavior and stability of electric vehicle transmission system.Explore the dynamic behavior and stability mechanism of the electric vehicle drive system impact response when considering the electromechanical coupling effect;And reveal the dynamic behavior mechanism of the drive system under different external excitation frequencies and parameters.In order to provide reference for the design of electric vehicle transmission system.The specific research content is as follows:Firstly,the nonlinear model of electric vehicle transmission system is established and simplified.Using Lagrange method equation,the nonlinear model expression of the drivetrain is established by introducing electromagnetic torque in the drive end.Secondly,the shock response equation is derived based on the nonlinear model expression of electric vehicle drivetrain.Based on the nonlinear dynamics theory,the number and stability of equilibrium points are studied,and the influence of the number and stability of equilibrium points on the impact response of the drive system is analyzed,and the mechanism of the impact response of the drive system under the action of electromechanical coupling is revealed.Thirdly,the number of equilibrium points,stability and bifurcation conditions of the nonlinear model are deduced based on the electromechanical coupling nonlinear model expression of the drive system of electric vehicle.Based on the mean equation and the amplitude-frequency response equation,the stability and bifurcation conditions of the resonance curve are discussed.The influence of electromagnetic parameters on torsional vibration of transmission system is studied by simulation.Fourthly,a relative rotation system is refined based on the electromechanical coupling model of the transmission system.The periodic excitation term is taken as the control parameter of the relative rotation system to judge the stability of the equilibrium point of the relative rotation system.The bifurcation behavior of the equilibrium point is studied by using bifurcation theory,and the bifurcation phenomenon of the equilibrium point on the parameter plane is analyzed by simulation,and the evolution law of the number and property of the equilibrium point with the change of the parameter is studied.The bifurcation diagram is used to study the evolution law of the dynamic behavior of the relative rotation system with the change of parameters.Fifthly,the impact response problem is tested based on the existing experimental conditions.The test is mainly divided into two parts:test the electromagnetic parameters of the permanent magnet synchronous motor,and calculate the stability of the impact response;The load shock is applied and the response process is measured,and the accuracy of relevant theories and numerical analysis results of the impact response analysis is verified by analyzing the impact response curve.