Research On Battery Management System Software Design And SOC Estimation

With the increasing fuel supply and environmental pollution problems,the development of pure electric vehicles has become one of the important ways to solve environmental pollution and get rid of dependence on fuel.As an important part of electric vehicles,power batteries have no doubt about their importance.The battery management system(BMS)is directly related to the driving range and service life of electric vehicles.BMS has played an important role in the smooth and reliable operation of electric vehicles.BMS processes information and faults such as voltage,temperature,current,and State of Charge(SOC)of power batteries in a unified manner,which facilitates the monitoring and alarming of real-time battery status information to improve the vehicle operation process Safety and reliability.Therefore,this paper designs the software of the lower computer and the upper computer of the battery management system.In this paper,the Thevenin model is used to make the battery equivalent.Through the mixed pulse charge and discharge experiment on the battery,the parameterized identification of the battery is completed.Both internal and external factors of the power battery can affect the accuracy of SOC estimation,and the Kalman filter method has advantages in dealing with nonlinear problems.Therefore,this paper designs a Kalman filter algorithm to estimate SOC.The algorithm establishes the battery circuit state space expression based on Thevenin equivalent battery model,and completes the SOC estimation on this basis.Simulate it to verify the accuracy of the algorithm.This article designs the lower computer software based on the hardware platform.Determine the operation process corresponding to each state of the system and the conditions required for the system state transition,and design the main management strategy of the BMS and the handling method of the battery system and the vehicle VCU failure.According to the functional requirements of the BMS host computer,the Lab VIEW platform is selected to design the host computer software,which realizes the functions of message reception,graphic display,command transmission,data storage,and disconnection when the communication is abnormal,and completes the function test of the host computer.Finally,build an experimental platform to test the BMS system.The test results show that the software can run stably and the host computer can realize functions such as alarm and information storage.