Research On The Battery Management System Of Electric Vehicle Based On Distributed System

With the increase of energy consumption, the development of new energy vehicles is payed more attention. More and more governments and car makers are competing to develop new technologies on EV. Battery management system (BMS) as the core components of EV is the research object of the research institutions. The main task of this project is to study the BMS in high-pressure monitoring, high and low voltage mixed-signal processing, temperature monitoring and the CAN bus network communication.On the base of analyzing the BMS of open literatures, designed a new high voltage monitoring circuit, solved the mixed high and low voltage signal processing, achieved a distributed temprature monitoring and internal and external CAN bus network communication. The main contents and results are as follows:(1) Gave up the analog multiplexer switch monitoring program, designed a new high-voltage monitoring circuit. The system can safely and reliably measure single battery voltage of 320V battery pack, whole measurement process can be completed in 120ms, and can discharge the battery pack for equalization.(2) Solved the mixed high and low voltage signal processing to achieve high and low parts of the sub-panel signal isolation communication, improved anti-jamming capability of the communication.(3) Completed each battery pack distributed multi-point temperature monitoring, temperature sensors can be easily expanded and temperature measurement can be completed within 1s.(4) Researched data transfer of BMS inner CAN bus network within the distributed system and researched high-speed CAN bus communication between BMS external CAN bus interface and car controller.(5) Researched the measures to improve the EMI of BMS hardware and carried out experiments. The results showed that: the BMS hardware can work reliably under the electromagnetic interference that was generated by 15kW drive motor.Through these studies, BMS sub-panels can monitor 320V battery pack stably and the highest monitor voltage is 1000V. Sub-panels can trasfer data under the electromagnetic interference environment of high-speed CAN bus network and lay foundation for further research.