一种新型的平面无源集成EMI滤波器结构

为了减小电磁干扰(EMI)滤波器的体积,提高开关电源的功率密度,提出一种堆积式交错并联平面无源集成EMI滤波器结构,将滤波器的共模电感、差模电感、共模电容和差模电容集成为一个单元模块,解决了现有结构难于集成大电容的问题,减小了集成电容的等效串联电阻(ESR)和等效串联电感(ESL);在考虑共模电感的等效并联电容(EPC)和共模电容的ESL以及它们的ESR情况下,建立了平面无源集成EMI滤波器的高频共模等效电路模型;利用二端口网络的A参数矩阵推导了插入损耗的计算公式。仿真和实验表明了该结构的有效性,以及高频模型和插损公式的正确性。

A Novel Structure of Planar Passive Integrated EMI Filter

In order to reduce the size of EMI filter and improve the power density of switch mode power supplies,a stacked-type interleaved planar passive integrated EMI filter structure is proposed in this paper.In this structure,the common-mode chokes,differential-mode inductors,common-mode capacitors and differential-mode capacitors are integrated into one unit.With this structure,the problem which large capacitor is hard to integrated is resolved,and the equivalent series resistance(ESR) and equivalent series inductance(ESL) of the integrated capacitor are minimized.The high-frequency common-mode equivalent circuit model is established taking into account the EPC of common-mode inductor and the ESL of common-mode capacitor and their ESR.The insertion loss formulas are deduced with "A" parameter matrix of two-port network.The simulation and prototypical experiment results are presented to show the effectiveness of the new integrated EMI filter structure and its high-frequency common-mode equivalent circuit model and insertion loss formulas.