Research On The Key Technique Of EMI Power Line Filter

Based on the network structure of EMI power line filter and the characters of soft ferrite, the computation method of Insertion Loss(IL) for the EMI power line filter and the design technique of filter inductor are given in this paper. Relationship between IL and relevant network parameters is presented by network theory. Network structure of EMI power line filter and its computation method for IL are discussed. Common mode and differential mode equivalent circuit model of single-phase power line filter and the high frequency distribution parameters model of filter device are established. Meanwhile, the main characters of soft ferrite are analyzed, and its implement on the EMI power line filter and its equivalent circuit model are given. According to the preceding theory, the software for IL of power line filter and the design of filter inductor are programmed. The difference between the imitative and practical results is analyzed, and the rational of the equivalent circuit model is tested. The application of EMI power line filter is discussed in the end.