Analysis And Design Of Electromagnetic Compatibility Of Electric Vehicle Battery Management System

Automobile industry is a pillar of economic development in our country and very important to the development of the national economy, car brought great convenience to people’s lives. With the rapid development of the automobile industry, the energy crisis and the pollution problem have become more and more serious. With the rapid development of the automobile industry, the energy crisis and the pollution problem have become more and more serious. Therefore, in recent years, many automobile manufacturers have invested a lot of human and financial resources in the development of new energy vehicles. Due to zero pollution and zero emissions characteristic of electric car, our country takes electric vehicles as the focus of current development of new energy vehicles. As the key device of the battery pack, good stability and precise data acquisition can make electric vehicles have longer mileage, higher security and more accurate State of Charge(SOC) estimation. Electric vehicle power system that consists of DC / AC inverter and DC / DC converter has high switching frequency and high current, it can form a strong electromagnetic interference(EMI) in the interior of the motor vehicle and is likely to result in BMS false alarm or inaccurate parameter acquisition, it also affect the car’s stable operation. Through the research on electromagnetic compatibility, we can effectively improve the battery management system’s radiation emission, radiation susceptibility, conduction emission, conduction susceptibility and ensure safe operation and the precision of the parameters acquired. Therefore, the electromagnetic compatibility design of battery management system has a very important practical value in engineering. On the basis of the development of battery management system, we describe three problems: research on electromagnetic compatibility of battery management system, power line’s conduction and radiation interference modeling and simulation, electromagnetic compatibility test.The EMC theory research includes emission theory research, conducted interference theory study and harness crosstalk theory study. The radiation emission is studied by using the current in the wire harness to be divided into the common mode and differential mode current. The main reason for the radiation emission is determined by the common mode current. In the conducted interference research part, the DC motor drive circuit is modeled as the research object, and conduction interference caused by the common mode voltage and common mode current are obtained through the calculation of the model. In the crosstalk part, this paper take single line to the CAN bus interference as the research object. The crosstalk model between the single line and the CAN bus is established and the parameter matrix is calculated. The CAN bus’ s near end voltage transfer ratio is obtained by the circuit analysis. Finally, the electromagnetic compatibility of the hardware circuit is improved by using the theory.BMS power line simulation includes conduction and radiation emission modeling. The model is established in the CST software, and it is mainly based on the requirement of EMC test standards. Meanwhile, the crosstalk of CAN bus is simulated.The test section includes the transmission and emission of the BMS+12V power line, the conduction susceptibility and radiation susceptibility test of the BMS data acquisition module. Based on the analysis of experimental data, the mechanism of equipment failure caused by electromagnetic interference is determined.