Research On The Lithium-ion Battery Simulator For Electric Vehicles

As the crises of environmental pollution and energy shortages caused by fuel vehiclesbecome increasingly serious, electric vehicles’ research begins to receive widely attention.With high energy density, long cycle life and low self-discharge rate，large capacity powerlithium-ion battery is expected to be the main power supply of the electric vehicles in the21st century.In the development and test for electric vehicles, application of powerlithium-ion battery has disadvantages，such as low efficiency, long trial cycle, high cost, etal.The application of regulated power supply instead of power battery to test is difficult tomeet various test requirements of electric vehicles. Therefore, the research and developme-nt of power lithium-ion battery simulator of electric vehicles is imperative.In this paper, power lithium-ion battery modeling, power lithium-ion batteryexperiments, system structure of power lithium-ion battery simulator, power lithium-ionbattery simulation, and hardware design of power lithium-ion battery simulation werestudied comprehensively.The paper firstly analyzed the research status of power battery modeling both homeand abrod. A improved equivalent circuit model was put forward considering temperatureand capacity attenuation, and correction method of circular internal resistance and tempera-ture was analyzed for the capacity on the model of power lithium-ion battery.Because itwas needed to extract model parameters and validate the model, related experimental study ofpower lithium-ion battery was to do. In the experiments, Arbin system and power lithiumiron phosphate battery(Sky of Energy) were selected to conduct related tests, extracting theparameters of improved equivalent circuit model, putting up the corresponding simulationmodel,and verifying the battery model with four different working conditions separately.R-esults showed that power lithium-ion battery model could reflect the output characteristicsof power lithium-ion battery commendably.Through the analysis of system structure of power lithium-ion battery simulator, asystem design scheme was put forward,consist of three-phase voltage source PWM rectifierand bi-directional DC/DC converter structure.Firstly,this design scheme would not onlyachieve dual energy flow but could give a wide range of output voltage change.Secondly,simulation model of power lithium-ion battery was established, doing the simulationexperiments under the rectifier mode’s load constant and load disturbance and under theinverter mode’s energy feedback. On this basis, the power lithium-ion battery simulator’s overall design, main circuit design and control circuit design were given.