电工技术学报2025，Vol.40Issue(6)：1805-1815,11.DOI:10.19595/j.cnki.1000-6753.tces.240297
电磁干扰滤波器中共模扼流圈的高频模型
High-Frequency Model of Common-Mode Choke in Electromagnetic Interference Filters
摘要
Abstract
As power electronic power converters move towards higher frequencies,it exacerbates the electromagnetic interference(EMI)issues in power electronic systems.Accurate modeling of common-mode chokes is crucial in designing EMI filters and predicting EMI noise in power converter systems.However,existing models struggle to represent the complex parasitic parameter structure inside common-mode chokes accurately.It leads to significant discrepancies between the actual filtering characteristics of common-mode chokes operating at high frequencies and their ideal designs.Particularly concerning are the insertion loss characteristics at multiple resonance points,where existing models struggle to fit the multi-resonance characteristics of common-mode chokes and exhibit entirely different insertion loss trends at high frequencies. Common-mode chokes can be divided into common-mode and differential-mode components based on the flow path of their magnetic flux.This paper primarily focuses on the analysis and modeling of the differential-mode component.The impedance testing method of traditional common-mode choke differential-mode models does not comply with the EN55017 testing standard.The main difference is that traditional impedance testing typically involves shorting one port of the common-mode choke to measure the differential-mode component.However,shorting the port alters the actual path of the differential-mode current,thereby failing to accurately characterize the complete inter-winding capacitance distribution of common-mode chokes,resulting in different trends between the two testing methods above 10 MHz.Additionally,the traditional common-mode choke differential-mode model assumes ideal inductance.However,when connected in series with the common-mode component at high frequencies,this idealization alters the filtering characteristics of the model's common-mode component.Therefore,the proposed differential-mode model should not exhibit a counteracting effect on common-mode current. Firstly,by analyzing the electromagnetic field distribution inside common-mode chokes,a new high-frequency model is proposed.This new model,when considering inter-winding capacitance,divides the inductance of the differential-mode component of one winding into two equal parts based on existing terminal capacitance.Furthermore,a new inter-winding parasitic capacitance branch is added between the two parts of the inductance,in conjunction with the existing terminal capacitance branch,to simulate the complete inter-winding electric field characteristics.Setting the differential-mode inductance as a coupled inductance with a coupling coefficient of-1 can fully counteract its influence on the common-mode component.This proposed model accurately fits the insertion loss characteristics of the differential-mode component of common-mode chokes under the EN55017 testing standard's multiple resonance points.Secondly,an equivalent circuit model is established under different insertion loss tests.Utilizing principles such as star-to-delta transformation and the Wheatstone bridge balance principle,the equivalent circuit is simplified,and circuit expressions are derived.Then,a comprehensive process for extracting parasitic parameters within the new model is proposed. Experimental conclusions are as follows.(1)Setting the inductance model of the differential-mode component as a coupled inductance with k=-1 does not attenuate common-mode current.(2)Compared with traditional models,the proposed new model exhibits good fitting accuracy within the frequency range of 150 kHz to 30 MHz and effectively represents the multi-resonance characteristics of common-mode chokes.关键词
电磁干扰/滤波器/共模电感/寄生参数提取/建模Key words
Electromagnetic interference/filter/common-mode chokes/extraction of parasitic parameters/modeling分类
信息技术与安全科学引用本文复制引用
兰宇杰,曾晓辉,陈为,陈庆彬..电磁干扰滤波器中共模扼流圈的高频模型[J].电工技术学报,2025,40(6):1805-1815,11.基金项目
国家自然科学基金(51777036)和《台达电力电子科教发展计划》资助项目. （51777036）
