Vehicle-Mounted Direct Current Bidirectional Metering System Of Electric Automobile

With the increasing popularity of electric vehicles in the future,it is of great significance to speed up fuel substitution and realize the transformation of China's current transportation energy power system,which is of great significance for reducing vehicle exhaust emissions and controlling atmospheric haze.The use of accurate and reliable DC bidirectional metering system will play an important role in the promotion of new energy electric vehicles.In this paper,the new energy pure electric vehicle is taken as the research object,the research status of electric energy measurement of electric vehicle at home and abroad is described in detail,and the metering and charging mode of electric vehicle under the mode of charging and changing electricity is introduced emphatically.The necessity and application prospect of the design of vehicle DC bidirectional metering system are expounded.The theory of regenerative braking energy feedback for electric vehicles is studied.The cyclic working conditions of urban and suburban roads are established by using advanced vehicle simulation software ADVISOR2002,and the relationship between instantaneous braking speed and reverse current is established.It can help to improve the charging effect,avoid parts damage,and also improve theservice life of power battery and the ability of battery life.Referring to the national standard of on-board DC metering for electric vehicles and combining with the actual metering demand,the design is carried out by the combination of MSP430 and BL6522 B "double core".The hardware part of the system including power management module,communication module,bidirectional metering module and control module.Based on the principle analysis and theoretical calculation of each circuit module,the hardware design of vehicle DC bidirectional metering system is completed.The software part adopts the idea of modular design,which can be divided into driving layer,platform layer and application layer architecture.Finally,the direct current energy interaction between the user and the system platform is realized by using Qt5.8programming technology.The experimental results show that the vehicle-mounted DC bi-directional metering system designed in this paper can be used as the " one car one meter " equipment for the cost settlement of electric passenger cars,which can realize the accurate measurement and data integration of the two-way electric energy.At the same time,it is also helpful to further study the energy consumption curve in the whole vehicle operation and the dynamic performance change of the power battery during the long term operation in theory.The development of the system has a broad application prospect for the popularization of new energy vehicles.