Conductive Electromagnetic Compatibility Key Technologies

With widely use of high-speed power switching devices, conducted EMI problems generated by power electronic equipments become more serious and have been a main restriction of progress of power electronic technology. So, researches of diagnosis technology of conducted EMI noise generated by power electronic equipments and mechanism of conducted EMI become more significant.Focused on reviewing the research of conducted EMI noise at home and abroad, The dissertation compares different kinds of discrimination networks based on hardware and software and proposes diagnosis technology of conducted EMI noise, the testing results of a commercial SMPS verify the effective diagnosis of this technology. Based on this, intellectual diagnosis system is developed, through noise extraction,disposal,diagnosis,analysis, effective noise suppression methods could be gotten, providing reference for electronic production design in order to satisfy international EMC standards.Research is also done on conducted EMI noise modeling technology. First, basic principle of conducted EMI noise modeling is elaborated, then several modeling methods are compared and experimental results of known resistances are given. Furthermore, some research on generation mechanism of conducted EMI of BOOST converter is done, conducted EMI models of BOOST converter are built, through experiments, influence of driving circuits,rising time,Cm between radiator and drain on EMI noise is analyzed. Simulation of conducted EMI is also done using Pspice software, influence of parameter variations on simulation results is verified. At last, some effective suppression methods of conducted EMI of SMPS are proposed: snubber circuit design and suppression of common-mode noise with balanced inductance. Simulation results verify the validity of these methods.