Modeling And Experimental Research On The Conducted Electromagnetic Interference Of Electric Automotive Motor Drive System

In recent years, environmental issues attracted wide attention of the whole society,people’s requirement for environmental protection become higher and higher. Becauseof the electric vehicle’s unique advantages of energy saving and environmentprotection, it has broad development prospect. The power electronic devices hasgreatly increased in electric vehicle compared to conventional cars, which bringcomplex automotive electromagnetic compatibility problems. Among them, the electricvehicle motor drive system is the most important sources of electromagneticinterference, it makes the cars difficult to meet the relevant vehicle electromagneticcompatibility standards and has adverse impact on the safety of driving the car and theexternal environment. In this paper, conducted EMI issues related to the electricvehicle motor drive system are investigated, the main work is as follows:①Learning the working principle of motor drive system in electric vehicle.Analyzes the electromagnetic interference mechanism in electric automotive motordrive system and the common-mode and differential-mode conducted EMI couplingpath.②In conductive EMI frequency range, permanent magnet synchronous motorhigh-frequency equivalent model was studied. The vector-fitting method is used tofitting the motor-port network function according to the parameters obtained from themotor-port impedance test, and the parameters of the circuit model is obtainedaccording to the network function equivalent circuit method. According to the theoryof multi-conductor transmission line(MTL), build the transmission line model ofcables.③A pure electric motor drive system conducted EMI experiment platform wasbuilt in the electromagnetic shielding room, the system’s common-mode anddifferential-mode conducted EMI simulation model was established using the proposedmodeling method based on the relevant parameters of the system. In the frequencyrange1kHz-30MHz, simulated and predicted the interference voltage on the LISN andthe interference current at the motor side. From the contrast results, prove the methodof predicting conductive EMI in motor drive system is correct and feasible. It alsoproved that the modeling method for various components of the system is correct.④Use the hybrid vehicles and hybrid system experimental platform for experimental research. Under three different working state(normal, high-speed,charging), measured the conducted EMI current spectrum in the motor drive system.Through analysis and comparison of experimental data, determined the motor drivesystem EMI band width and interference coupling path, and verified the EMImechanism of the motor drive system. Established the hybrid motor drive systemconducted EMI simulation model, by the model simulation, hybrid vehicle test andhybrid experimental platform measured results, further demonstrate the feasibility andvalidity of modeling method.⑤Use dynamometer test platform to further test the motor drive systemconducted EMI under a variety of conditions (no-load, load, charging). Establishedmotor drive system conducted EMI simulation model to verify the modeling methodfor the conduction EMI in the motor drive system is predictive accuracy and feasibilityunder actual operating conditions.