| In recent years,with energy saving and emission reduction,green travel and related preferential policies,the sales of pure electric vehicles have been increasing every year,with huge market prospect and potential.Every electric vehicle is equipped with a battery management system(BMS),so the related research on battery management system of pure electric vehicles has become a hot topic.Firstly,this paper investigates and analyzes several common on-board power batteries,compares and analyzes the performance parameters of power batteries,and selects ternary lithium battery as the power battery studied in this paper.Then,the equivalent circuit models of several power batteries are analyzed and compared,and the first-order THEVENIN equivalent circuit model is selected.Then the HPPC experiment was carried out to fit the data and identify the parameters of the equivalent circuit model of the power battery.Then,the function and structure design and control strategy research of the battery management system are described in detail.It mainly includes the selection of centralized battery management system structure,the overall framework design of battery management system,and the current transformer method and indirect voltage collection method for the design of power battery status monitoring.The safety protection module and thermal management are designed and the relevant control strategies are given.The design of data information management chooses the method of combining communication,data and monitoring.The fusion algorithm based on un-traceless KALMAN filter and open circuit voltage method plus ampere-time integral correction is selected in the design of residual power estimation.Finally,Simulink model simulation and hardware in-loop test were carried out.Model simulation mainly includes battery simulation model,battery temperature and control strategy of the simulation model,equilibrium control simulation model is established,the battery SOC estimation the establishment of simulation model,driver model,the establishment of a permanent magnet synchronous motor model,the establishment of the vehicle dynamics model,finally the above model for the integration of the vehicle simulation model.In addition,based on the overall architecture design of hardware and related software such as NI real-time simulation system and BMS controller,a hardware in-loop experiment platform was built to conduct routine performance test,condition test,communication test and safety test,thus verifying that the battery management system designed in this paper achieves the expected design effect. |
