Study On Electromagnetic Radiation Interference And Sensitivity Of Vehicle

In recent years, vehicle technology is continuously developing toward electronicand intelligent, electronic equipments in vehicle are becoming more and more, whichmake the electromagnetic environment of vehicle more complex. As the tie thatconnects all kinds of electronic equipment, wire acts as the transmission carrier of theelectronic signal, and its electromagnetic interference characteristic plays an importantpart of role in the electromagnetic compatibility problem of vehicle. Hybrid vehiclewas taken as the research object in this paper. On the basis of previous studies, thispaper mainly discussed the simulation modeling of several typical radiationinterference sources of the vehicle, and then put the radiation source model into thevehicle model, in the end this paper researched the electromagnetic radiationsensitivity problem of the wire. The main works of this paper are as follows:1) Based on Maxwell integral equation, this paper introduced the basic principleof moments method, the continuous equation was discretized into the algebraicequations, and a set of basis function and weight function would be selected totransform functions into a matrix equation, then the matrix equation was solved to getthe coefficient matrix. Based on the theory of Moment of Method, a simple and easyantenna model, whose boundary conditions was set up, was built, then the currentdistribution on the antenna was derived in detail.2) Based on field line coupling theory, induced current was solved in atransmission line above lossy ground, and then according to the scattering theory perunit length impedance and admittance were derived in detail, finally differential linesegment model of the transmission line is established above lossy ground.3）This paper introduced the three elements of electromagnetic interference, andrevolved around three elements to analysis. Firstly it was analyzed the electromagneticinterference mechanism of interference sources inside vehicle; then radiation couplingwas introduced in detail, and the common mode radiation and differential moderadiation were emphatically analyzed, the formula of the common mode voltage anddifferential mode voltage were deduced formula. The electromagnetic radiation modelof interference sources were established according to the analysis of interferencemechanism.4) Two different simulation soft wares were used to calculate the induce current of the vehicle interior wire under the antenna’s electromagnetic radiation, the relativeerror and the correlation were analyzed according to the calculation results, whichverified the validity of the vehicle body model from the simulation. Theelectromagnetic radiation model of vehicle ignition system was built, and was verifiedfrom the experiment, thus which further verified the validity of the model of vehiclebody.5) To establish the electromagnetic radiation model of interference sources andput them into the vehicle model, the electromagnetic field distribution inside thevehicle and the induce current of the vehicle wire under electromagnetic radiation werecalculated by simulation, at the same time which also laid a foundation for the study ofthe equivalent model of vehicle wire. On the analysis of the various factors influencingthe electromagnetic sensitivity of vehicle wire, in order to solve the problems ofmultiple variables at the same time, using a single variable method, the simulationresults were analyzed to summarize the effect of various factors on the electromagneticradiation sensitivity of the vehicle wire, and which was summed up the way to improveelectromagnetic interference effect on the vehicle wire.