Analysis And Suppression Of Electromagnetic Interference In Quasi-Z-Source Inverter Systems Of Electric Vehicles

In recent years,environmental issues have attracted more and more attention.The contradiction between fuel consumption and environmental issues has become increasingly acute.As an energy-saving vehicle that does not consume fuel,new energy vehicle have become the focus of attention and the development trend is very well.New energy electric vehicle has less pollution and has a good application prospect.However,new energy vehicle also has deficiencies,so the application of electric vehicle is also subject to certain restrictions.Due to the large number of power electronic devices used in electric vehicle,the electromagnetic compatibility problems are also more serious than conventional car.The inverter system in electric vehicle is one of the main sources of electromagnetic interference.It will produce serious electromagnetic interference and affect the normal operation of electric vehicle.The EMI issue is an important aspect affecting the electric vehicle market.In order to study the electromagnetic interference problem of electric vehicle,a quasi-Z source inverter system for electric vehicle was studied,and conducted EMI and radiated electromagnetic interference were studied.The main research contents are as follows:First,the structure and control principle of the quasi-Z source inverter system for electric vehicles are introduced.The EMI generation mechanism and the propagation paths of common mode EMI and differential mode EMI are analyzed.The conducted interference voltage is deduced and the generation of radiated interference is briefly described.The establishment of a model in the path of conducted EMI in quasi-Z source inverter system is introduced,the method of interference measurement is explained,finally the simulation model is seted up,the interference voltage and current accordingly are analyzed.In order to understand the system's electromagnetic interference more intuitive,the corresponding changes generated by interference is analyzed,by changing the value of parasitic parameters.Secondly,the principle and method of suppressing EMI in the system for electric vehicle are analyzed.A small and high-efficiency EMI filter is used to suppress conducted interference and design a common-mode voltage in this thesis.Using the method of suppressing the reverse compensation,the interference voltage detection circuit and the compensation circuit are designed,and the parameters are calculated.Finally,the simulation circuit is established in MATLAB and the suppression method is simulated.The analysis showed that the inhibition method can effectively improve the electromagnetic environment of the electric vehicle,indicating that the suppression method is effective.Finally,the radiated interference principle of the quasi-Z source inverter system for electric vehicle is analyzed.Quasi-Z source inverter is used as sources of radiated interference.An interference model is established in the simulation software Ansoft HFSS toanalyze the radiated interference generated by the inverter system,including the radiation interference to the frequency converter itself and the electric vehicle environment,there is a clearer understanding of the EMI problem of electric vehicle.