Research Of Secondary Development For Electric Vehicle Battery State Detection System

Battery state detection,including State of Charge and State of Health,is an important function of the electric vehicle battery management system.With the rapid development of the electric vehicle industry,the algorithm research of battery state estimation has also made many results,but the mature and effective technical specifications in the field of automotive electronic control development,has' t been used for reference,so the development efficiency is low.In view of the above problems,based on the traditional V mode,this thesis proposes a secondary development mode for the battery state detection system,which include two steps of prototype system development and function development.The first development realizes the hardware system and basic software functions,and the second development realizes the function of state detection.Firstly,based on the versatility of the system,the hardware circuit of the master-slave structure is designed.Based on TI F28M35 dual-core microcomputer,the minimum system and isolated communication circuit of the main control module are designed.Based on TI bq76PL536 A battery management chip,the analog front-end circuit including battery equalization,voltage measurement,internal resistance measurement and temperature measurement is designed.The hardware system designed in this thesis not only meets the needs of battery state detection,but also has the interface and structure to realize the battery management system.Secondly,the software prototype system is designed based on the hardware system,including the underlying software such as CAN and SPI communication driver,battery parameter monitoring and task scheduling.Then a BASIC-like interpreter is embedded on the underlying software.The interpreter obtains the BASIC code automatically generated in the secondary development environment and is responsible for the execution of the specific algorithm,thereby changing the non-real-time algorithm in the simulation environment into a program that the embedded microcontroller can run in real time.Thirdly,the software secondary development environment was designed on the PC.The 2RC model and the extended Kalman filter-based SOC algorithm module are built in the MATLAB/Simulink,and the effectiveness of the model and algorithm is verified by simulation.An automatic code generator was then designed to convert the SOC and SOH detection model under Simulink into BASIC-like code.Then based on LabVIEW,the CAN communication software was designed,which is used for code translating and battery parameter monitoring.Finally,this thesis builds a system test platform,which verifies the hardware system and software system respectively.For the hardware system,the communication module and the battery parameter monitoring module were tested.The test results prove that the hardware monitoring data is credible.For the software system,the extended Kalman filter method and the internal resistance method are taken as two examples,which test the SOC and SOH detection function of the system.The test results prove the practicability and high efficiency of the system.