The Design And Implementation Of BMS Hardware System For Electric Motocycle

In today's life,as a type of environmentally friendly and convenient green transport,the electric motorcycle is popular with the public.However,the common electric motorcycle on the market is not equipped with battery management circuit.This causes the wrong use of the battery,leading to battery damage,and shortening the life of the battery.Therefore,a stable and reliable battery management system which can not only monitor and adjust the status of the battery in real time,but also strive to avoid the wrong use of the battery and extend the battery life is necessary.In this paper,the characteristics of lead-acid battery are analyzed in the light of data.Based on the usage scenarios,the battery management system architecture is designed.The BMS circuit is designed under the premise of controlling the cost.To the display and uploading of the battery information,the adaptive front panel circuit is designed for users to interact with the battery management system.Battery management system is designed based on chip STM32F103ZET6,including battery information monitoring circuit,battery balancing circuit,communication circuit,charge and discharge control circuit.Battery information monitoring circuit is mainly for battery voltage,current and temperature acquisition.The battery balance circuit can equilibrate the battery power.The communication module sends the battery status information and receives the control information from the front panel circuit.Charge and discharge control circuit can monitor the process of charge and discharge,avoiding the overcharge and over-discharge.The system uses transformers for battery balancing,achieving higher equilibrium efficiency.Based on the collected battery data,a SOC estimation program is designed.To supply the power to the electric motorcycle,this article also design a high transfer efficiency switching power as 12 V low voltage power.After development and testing,functions of BMS have been achieved.The BMS can monitor the voltage,current and other information in real time.The balance circuit would turn on to equilibrate the batteries when their difference is becoming larger.The estimation error of battery SOC is less than 5%.Control circuit protects battery charge and discharge,thus the safety of battery is improved.The communication of BMS circuit and the front panel circuit is running well.The 12 V power supply circuit provides stable power for other low-voltage systems of motorcycle.After a period of on the road test,result shows that the battery management system has achieved the desired requirements.