Research On Conducted Interference Of EV Driving-Charging Integrated System Based On Interleaved DC-DC

With the rapid development of China’s automobile industry,the number of electric vehicles continues to rise.Due to the large number of high-frequency power electronic devices used in the on-board devices of electric vehicles,conductive interference will be generated during normal operation,which leads to the increasingly serious problem of electromagnetic compatibility.This paper mainly studies the conductive interference of the drive-charge integrated system of electric vehicles,analyzes the mechanism,propagation path and simulation model of the conductive interference when the driving mode and charging mode of the integrated system work in a stable state,and conducts the interference suppression of the integrated system.Circuit principles and integration methods of traction and charging integrated system are introduced.There is a deviation between the actual working state and the ideal working state of the system,and the main source of the deviation is the parasitic parameters generated by each part of the system in the actual work.In order to correctly analyze the conductive interference as far as possible,this paper extracts the parasitic parameters of each part of the integrated system: The parasitic parameters of bus are extracted and the loop inductance is extracted,The high frequency model of inductance and capacitance is established and simulated.The transmission line model is established to analyze the double-conductor transmission line circuit model and three-conductor circuit model.According to the obtained cable parameters,analyze the inverter output cable,so as to establish an inverter output cable three-conductor equivalent circuit cascaded by the multi-segment aggregated parameter equivalent circuit model.The extraction and analysis of conductive interference are introduced.The composition of the driving-charge integrated system and the circuit of conducting interference are analyzed,and the common mode circuit of the system is emphatically analyzed.The system model is built in the simulation software,and the conducting interference simulation is carried out for the two working modes respectively,and the common mode interference and differential mode interference are extracted.The influences of bus parasitic parameters,switch tube parasitic capacitance and inverter output cable on the system conductive interference,differential mode interference and common mode interference are analyzed,and the relationships between DC-DC module and inverter module and the whole system conductive interference as well as differential mode interference and common mode interference are also analyzed.The method of conducting interference suppression in driving mode and charging mode of the driver-charging integrated system is analyzed.In the driving mode,frequency jitter method is applied to suppress the conducted interference of DC-DC module,which can effectively eliminate the interference peak.TSPWM control method is applied to reduce the frequency of inverter common-mode voltage fluctuation so as to suppress the interference of inverter module.In charging mode,the difference of conduction interference between bipolar modulation and unipolar modulation is analyzed.EMI filter is designed to suppress the conduction interference.Finally,the driving-charge integrated system can meet the Class 5 limit of conductive interference of national EV components under two working modes.