Analysis Of Nonlinear Vibration Characteristics Of Pure Electric Vehicle Electromechanical Coupling System

At present the development of electric vehicle technology has become the focus of governments and automobile industry.All countries are actively developing electric vehicle technology.There are already mature electric vehicles in the market.The electric vehicle is an effective way to solve the problem of environmental pollution of oil resources and the increasingly serious crisis.Electromechanical coupling drive system is a typical electromechanical system,which is widely used in the field of vehicles.In the engineering practice,the electromechanical coupling effect makes the electromechanical transmission system show very complex dynamic characteristics.At present,the research on the torsional vibration of the automobile powertrain system is mainly at home and abroad,and the research on the torsional vibration of the pure electric vehicle transmission system is still in the initial stage.This paper studies the influence of internal motor parameters and external load excitation on the nonlinear characteristics of the transmission system.Based on the theory of electromagnetism,electromagnetic theory and electromechanical analysis,the electromagnetic torque expression is derived,and the nonlinear torsional vibration model of pure electric vehicle electromechanical coupling transmission system is established.The multi-scale method is used to solve an approximate solution of the vibration equation in the main resonance case.The frequency response equation of the transmission system is solved and the stability of the solution is analyzed.By studying the changes in the system parameters such as the internal power factor angle,the number of ampere turns,the number of pole pairs,and the saturation factor of the magnetic circuit in the unstable area of the system,it can be seen that the change of the motor parameters will cause the resonance and unstable area of pure electric passenger train transmission system to increase,which will lead to instability of the transmission system.Through the study of pure electric vehicle transmission system of electromechanical coupling nonlinear torsional vibration model,the equilibrium point of an undisturbed Hamiltonian system in the case of electromechanical coupling is solved,and using the Melnikov method to solve the bifurcation threshold curve,analyze the impact of dynamic mechanical loads on the nonlinear dynamic behavior of an electromechanical coupled transmission system of a pure electric vehicle.Through the above analysis,it can be seen that the motor parameters need to be controlled within a reasonable range in the motor design process,so as to improve the stable operation of the torsional vibration of the electromechanical coupling system.Due to the influence of excitation,the electromechanical coupling transmission system of pure electric vehicle has complex nonlinear dynamic behavior,such as periodic,quasi periodic and chaotic.Under certain conditions,the electromechanical coupling transmission system of pure electric vehicle is subjected to the effect of aperiodic impact,resulting in larger dynamic load and nonlinear torsional vibration,which seriously affects the reliability and durability of pure electric vehicle transmission system.Based on the Melnikov theory,the bifurcation and chaos characteristics of the transmission system are analyzed,so as to solve the system stability operation boundary condition and avoid the unstable condition of the pure electric vehicle.