Research On Double Core Differential Common-mode Inductance Integrated EMI Filter

In order to meet the requirements of power electronic devices in EMC, input filter is used to improve the performance of power electronic devices in EMI.This paper analyzes the research status of EMI filter technology and that of the integrated EMI filter at home and abroad.In the terms of reducing the volume and improve the power density, the dual core magnetic core of EMI filter integrated is put forward, the EMI filter integrated has two magnetic cores which are the differential mode inductance single winding and common-mode inductance wound. We also come up with a double integrated magnetic core of EMI filter structure which can increases differential mode inductance using local core.(1)We analyze the principle of integration of EMI filters integrated by differential common-mode inductance with double cores applying the method of magnetic circuit analysis,analyzing the influence of resistance of the magnetic core unbalance on EMI filters made up of double integrated magnetic cores which are differential mode inductance single winding and common-mode inductance double winding.(2)Modeling is based on the theory of two-port network analysis for each kind of double core differential common-mode inductance integrated EMI filter in high frequency, we set up the integrated common-mode inductance of the two port equivalent circuit, and use the electromagnetic field finite element calculation, experiment and test method to extract the electromagnetic parameters, deduce the formula of insertion loss, and give the calculation curve and the simulation curve, and obtain the measure curve through the test of insertion loss.(3)we study the structure of complanation for EMI filters with double cores integration differential common-mode inductance, giving a structure plan of the magnetic core and winding structure of complanation, winding1 method is given.Through analysis of unbalanced resistance of the magnetic cores which are differential mode inductance single winding and common-mode inductance practical conclusions on the impact of the dual integrated magnetic core of EMI filter.Through the calculation,simulation,experimental test and the insertion loss curve contrast, we validate the correctness of theoretical analysis and the accuracy of the equivalent circuits.