Research On Intelligent Charging System And Control Strategy For Pure Electric Vehicles

With the aggravation of environmental pollution and energy crisis,electric vehicle has gradually become the focus of research in the automotive industry all over the world.However,pure electric vehicles rely on external charging to maintain energy by using power battery as power source,and electric vehicle charging system has become a key to ensure the operating distance and charging rapidity of electric vehicle.Nowadays,the charging system of electric vehicle still has many problems,such as long charging time and high charging cost.In this paper,the charging system structure and charging control strategy of electric vehicle charging system are studied.Based on the overview of various types of electric vehicle battery,the working principle and charging and discharging characteristics of the lithium ion battery are analyzed.Then the simulation model is established for lithium ion battery according to the mathematical model of Partnership for a New Generation of Vehicles(PNGV).After that,the intelligent electric vehicle charging system circuit structures are investigated.By selecting the multilevel topology structure as the research object,the circuit structure and parameters design of the main circuit topology of PWM rectifier and a bidirectional DC/DC converter are analyzed deeply.Consequently,the simulation model of the main circuit is built.The conventional charging methods of electric vehicle battery,such as constant current charging,constant voltage charging,charging stages,as well as the electric vehicle fast charging method,are analyzed.Then an intelligent charging control strategy and is proposed based on the main circuit topology in this thesis,based on which a PWM rectifier and a bidirectional DC/DC converter control strategy are presented.Simulation models are established in MATLAB/Simulink,so that the simulating results can be obtained and analyzed.Finally,experimental researches on intelligent charging system is carried out.A set of intelligent charging system experimental platform is obtained based on TMS320F28335,in which the hardware circuit and the corresponding control program is designed.Charging and discharging experiments are achieved.Experimental results prove the feasibility of proposed charging system.