EMI Filtering Technology Research Of Inverter

With the development of science and technology, power electronics equipment has beenwidely used in People’s Daily life, resource development, space exploration, national defenseconstruction,in various fields of the national economy developmen. Electronic electricalequipment is not only the quantity and the species on the increase, but also in towardsdigitization, high speed and the direction of the network fast development. However, thepower electronic equipment in the working, it will produce some useful or uselesselectromagnetic noise, the interference may bring adverse effects to own or other equipment,power grid and biological.In order to retrain the electromagnetic interference problemproduced by power electronic equipment effectively, all countries in the world have issued alot of strict electromagnetic interference standard, and increase the personnel and materialresources input on electromagnetic interference suppression technology research, purified thesurrounding electromagnetic environment effectively.Currentlly, The electromagnetic interference suppression mainly have three kinds ofmethods: The first is through improving semiconductor devices, magnetic components andPCB layout, etc, from the source to eliminate electromagnetic interference. The second isaccess the EMI filter to circuit, absorpt and eliminate the electromagnetic interferenceproduced by power electronic equipment. The third is shielding protection the key equipment,prevent the equipment influented by electromagnetic radiation of the others, and influent theothers.This paper based on development present situation of the electromagnetic interferencesuppression technology. Established the high frequency equivalent model of the passivecomponents, this paper puts forward a kind of brand-new parasitic parameter extractionmethod. Through analysis to the passive EMI filter, it obtained the filter struction selectprinciples under in different source and load impedance, and the design method when theimpedance mismacth. According to the passive EMI filter deficiency in the actual application,introdact the active EMI filter. The branch impedance equivalent transformation principle,Analyses and studies the active EMI filter model and characteristics. Based on the singlephase grid inverter, this paper analyzes the influence in different PWM way for inverter EMI,designed a active EMI filtr circuit and used to a three-phase inverter system. Use the Saber tosimulation, analysied the effective of active EMI filter to commom-mode EMI and conductiveEMI in a three-phase inverter.