Research On The Electromagnetic Radiation Of DC/DC Converter For Hybrid Electric Vehicle

New energy automobile has been required and gradually developed with oildepletion,mountingoil prices and environmental degradation, which become a globalindustry.The hybrid electric vehicle（HEV） is a new kind of vehicle for a pureelectric vehicle development process for marketization. It can significantly reducefuel consumption emissions.At Domestic and Overseas Market,people generallyagreed that it is less investment, great choice, easy to meet standards of futureemissions and energy efficiency, and it is mainstream vehicle being high acceptancemarket.As an essential component of hybrid electric vehicle,the DC/DC converter is oneof the main electromagnetic interfering sources.The DC/DC converter can generatestrong electromagnetic interference,which makes the vehicle unstable operation oraffect the vehicle’s electrical equipment work properly.Therefore,the research ofelectromagnetic compatibility of the DC/DC converter is significance. We must giveenough attention to electromagnetic compatibility problems.Until to the design stage of molding forming, Many people now simply test tosolve the electromagnetic radiation of the DC/DC converter,the method is not onlycomplex, but also using higher costs, and the effect is not particularly desirable. Thestarting point of this paper is that we can analysis and predict electromagneticcompatibility through simulation in automotive design stage,we timely find outradiation interference,then we can take effective suppression and protective measures,solve problems of electromagnetic interference the best possible.In this paper, We use DC/DC converter simulation of electromagnetic radiationof the radiationsource, inhibition and experimental verification-based as the specificmethods of our paper.and the main electromagnetic radiation resources (Highfrequency loop radiation sources, high voltage sources, control circuit rate conductorsignal interference sources) on the DC/DC converter are simulated and we givecorresponding improvement solutions and measures,based on which,strictlyAccording to the national standard GB18655-2010the second part,we make testabout electromagnetic radiation strength for DC/DC converter and the vehicleinstalled DC/DC converter, methods are proved that they are feasible and superior.The research of the paper are as follows: Make the analysis on electromagnetic radiation mechanism for radiation deviceof the DC/DC converter, and find the source of electromagnetic radiation field ofDC/DC converter from the point of electromagnetic compatibility.According to thetheory of electromagnetic prediction, we set up the mathematical model,Mathematical expression are deduced,according to the practical circuit structure andworking environment,the boundary conditions are established, using HFSS and EMCStudio simulation software,simulation images are maked,.then analyze theelectromagnetic radiation reason through the simulation images.According to simulation images about the electromagnetic radiation source, weput forward the control measures.We can take shielding method to suppress theelectromagnetic radiation.The numerical expressions of the ideal metal shielding arededuced.But,due to the fact that there are some apertures of the metal body,commonelectromagnetic leakages are inevitable.Diffraction field formulas through theaperture are deduced.by using diffraction theory,and make analysis and comparisonon shielding effectiveness of some graphics,we get results that the width to lengthratio’s is the better, And on the equal area, shielding effectiveness on many holes isbetter than the single-hole.In addition, the circuit method combining with thesimulation results is maked on the suppress measures.According to the second part of the national national standard GB18655-2010,we make test about electromagnetic radiation strength for DC/DCconverter and the vehicle installed DC/DC converter,and compare with two differentstate electromagnetic radiation scanning about the before and later.The experimental results show that electromagnetic radiation interference ofDC/DC converter,by shielding and takeing circuit lmeasures, is diminished a lot，which is up to the national standard. In conclusion, the method of taking modeling,simulation and predicting combining with taking the corresponding suppressingmeasures are correct and effective for electromagnetic radiation of DC/DC converter.