Research On Electric Vehicle Power Battery Simulation Technology And Field Test Methods Of Charging Equipment

With the rapid development of electric vehicles in our country,the technical fields regarding the inspection and maintenance of electric vehicle charging equipment are getting more and more attention.Field test can timely discover potential safety hazards in the equipment to ensure the safe and stable operation of charging equipment.In order to improve the standardization,flexibility and practicability of the field test,the electric vehicle battery simulation technology and field test methods of charging equipment was studied in this paper.The necessity of field test of electric vehicle charging equipment was analyzed and the relevant type test standards that can be as reference were sorted out in this paper.By analyzing the requirements for field test and the feasibility of the test scheme,the items that must be tested and the items that need not be tested were summarized,which can provide a basis for the contents and methods of field test of off-board charger.Aiming at the shortcomings of the traditional charging load for field test of electric vehicle charging equipment,a power battery simulation technology for field test of off-board charger by combining an improved power battery model and a lightweight charging load is proposed.Among them,the on-board power battery pack of mobile detection vehicle cascaded DC converter is used to form the lightweight charging load.By designing the control strategy of the DC converter,the charging load has constant voltage,constant current,constant power,and constant resistance modes and the ability to be continuously adjusted within the rated range.The design is small in size and light in weight,and can simulate different types of power battery packs with different parameters to meet the field test of off-board charger.By analyzing a typical case of an electric vehicle charging accident,an field monitoring method for charging faults of off-board charger based on battery model is proposed.The charging communication process and protocol between the off-board charger and the battery management system are analyzed in detail.The CAN bus monitoring technology is used to receive and analyze the charging information.The charging response information simulated by battery model is compared with the charging state information of battery,and the charging state information of charger is compared with the battery charging demand information to determine whether the charging process is normal.When it is judged that an charging error occurs,a fault early warning signal is issued in time.This method can identify 10 types of faults including BMS function failure.Comparison and analysis of actual charging accident data and power battery model data verified the feasibility of the field monitoring method for charging faults proposed in this paper.