Research And Implementation Of EV Distributed Battery Management System

With the rapid development of automobile industry in the new century,the electric vehicle has been attracting the attention of people all over the world,as the main development direction of future automobiles.Battery Management System(BMS),one of the core technologies of electric vehicles,is also attracting more and more attention from automobile companies around the world.BMS detects and manages the entire process of storage battery of electric vehicles,including battery status detection and estimate,battery safety protection and information management.The main work of this dissertation is to develop a battery management system for pure electric vehicles.The system hardware,software and testing are researched and implemented.The BMS adopts master-slave distributed structure.Through the CAN bus,the main control board and the slave control board achieve data interaction.The number of control board can be expanded according to the number of managed battery cells.The battery state of charge(SOC)estimation and insulation testing methods was conducted in-depth study.The system is designed according to the analysis of BMS function and structure.In the implementation of the system,this paper analyzed the design principles of each hardware module,designed the circuit schematic diagram,and introduced the detailed implementation process of the hardware and software of the main modules.These modules realize the functions of total voltage collection,current collection,insulation detection,the collection and equilibrium of single battery voltage,and temperature acquisition.The design process fully considers the anti-interference performance of the system.The main control board takes TC1782 as master chip,designed for automotive applications by Infineon.This board realizes the voltage current collection,SOC estimation algorithm operation,balancing strategy execution and inter-device communication.The slave control board equipped with the LTC6804 achieved single cell voltage acquisition,passive equalization,temperature acquisition and other functions.The LTC6804 supports SPI communication,which has a cascade function.Through the isolated communication interface(ISO SPI)LTC6820,Master chip and multi-LTC6804 chip communicate.Finally,through the bench test and the real vehicle test,the relevant data were recorded by CANoe.The experimental results show that the battery management system developed in this paper is safe and reliable.The BMS can collect the voltage,current,temperature of battery in high-precision,realizing SOC estimation and battery insulation detection,which proves the correctness and practical value of this dissertation.