Study On Dynamic Characteristics Of Pure Electric Vehicle Electromechanical Coupling System

With the gradual deterioration of environmental pollution and the reduction of non-renewable resources,the research and envelopment of energy technology has become a hot spot in the industry.Governments of various countries have introduced relevant laws and regulations to promote the development of vehicle technology,pure electric vehicles As a major branch of new energy,it has become a key development and research object in my country.The electromechanical coupling transmission system of vehicle is different from the traditional automobile transmission system.It is composed of motor part and transmission part.It is a very typical electromechanical coupling system.In actual engineering,the electromechanical coupling effect will cause the electromechanical transmission system to behave quite complex dynamics.According to the retrieval of a large number of literatures,the current research on automotive power transmission systems by domestic and foreign scholars is mainly concentrated on traditional cars and hybrid electric vehicles.Therefore,this topic takes the electromechanical coupling transmission system of pure electric vehicles as the research object.The main research content can be summarized as follows.(1)According to the pure electric vehicle powertrain structure,combined with the theory of electrical machinery and vehicle dynamics,the electromagnetic torque expression of the vehicle driving motor is derived,and the gear pair vibration is built through the structure between the components of the electromechanical coupling system The model and the pure electric vehicle transmission system model are combined with the two to establish an electromechanical coupling dynamic model considering electromagnetic torque excitation,which provides a theoretical basis for the following research.(2)Based on the mathematical model of the motor in system,the speed loop simulation module,the current loop simulation module and the space vector pulse width modulation module were established respectively,and the electromechanical system was constructed through the mechanical part,the motor part and the control part.Coupling dynamics simulation model,and vector simulation to it,the simulation results show that the electromechanical coupling vibration can be controlled by controlling the shaft current component of the synchronous motor.(3)The torsional vibration model of the electromechanical coupling transmission system of vehicle is established,and the small disturbance term is ignored.The equilibrium point of the Hamilton system is solved and its stability is classified.The system bifurcation threshold curve is obtained by the Melnikov method and passed The Runge-Kutta is carry out the system,revealing the influence of the dynamic load of the pure electric vehicle on the dynamic behavior of the system.(4)Established an analytical model of unbalanced magnetic tension based on the Maxwell-Tensor method,and established an imbalanced magnetic tension simulation model using finite element software and simulated it,and the magnetic force distribution under the asymmetric air gap and the unbalanced magnetic tension amplitude under different eccentric conditions were compared between the analytical model and the simulation model,verifying the accuracy of the analytical model.(5)Taking into account the influence of unbalanced magnetic tension on the lateral vibration of the electromechanical coupling system,the electromechanical coupling lateral vibration model under the action of unbalanced magnetic tension is established,and the influence of the two parameters of internal power factor angle and eccentricity on the pure electric vehicle is analyzed and the influence of the natural frequency of the lateral vibration of the system.Finally,according to the internal power factor angle,rotor eccentricity,excitation amplitude and other parameters,the vibration reduction measures and methods of the electromechanical coupling system are explored.