Research And Design Of Key Circuits In Battery Management System Of Electric Vehicle

In order to alleviate the pressure on environment brought by harmful exhaust emissions from traditional automobiles,the new energy automobiles emerge at the historic moment,among which electric automobiles have become a typical representative.Battery management system is one of the most important management systems of electric vehicles,which has become the target of research of enterprises and universities at home and abroad.Battery management system with complete functions and excellent performance,which can not only optimize the performance of battery pack,but also protect the battery in any abnormal situation,so as to ensure the safety and long life of the battery pack.At the same time,it can improve the efficiency of electric vehicles,the safety of driving and finally achieve the high efficiency of battery capacity and energy utilization.Therefore,battery management system technology should be deeply studied.Based on the existing battery management system of electric vehicle,aiming at the problems of battery management system in serial communication,cascade application and balanced management,the key technology circuits of battery management system of electric vehicle are studied and designed in this paper,which mainly includes isolated serial communication technology circuit,cascade technology circuit for battery pack and balanced management technology circuit.Due to electric vehicles need timely feedback on battery pack usage information in the driving process,an isolated serial communication interface technology is proposed this paper.The various complex situations in data transmission can be reduced,the stable and effective data transmission can be guaranteed,and the driving safety can be improved by using isolation transmission technology.Through using batteries cascade,which can reduce the complexity of circuit design and improve the reliability of signal transmission,so two cascaded battery pack technologies are proposed in this paper,which include isolation daisy chain cascade technology and non-isolation cascade technology.In addition,the consistency of battery power in electric vehicle batteries is very important,and the inconsistency between battery power will bring serious security risks.Therefore,the two passive balancing methods are proposed in this paper,which can effectively reduce the complexity and improve the reliability of the system,and also provide strong support for thebalanced management of batteries.The isolation serial communication technology circuit,cascade technology circuit for battery pack and equalization management technology circuit are proposed in this paper with0.18μm BCD process.However,the isolation serial communication interface circuit mainly includes pulse identification and conversion unit,wake-up unit,information sending unit and information receiving unit.Then,the circuits of each module are simulated and verified,and the layout of the isolated serial communication interface circuit and the simulation results based on Modelsim and NC-Verilog software are given.