EMI滤波器高频寄生参数分析

Parasitic parameters analysis of EMI filter

开关电源的高功率密度、高开关工作频率和紧凑结构,对其电磁兼容提出了更高的要求,为了设计高性能的EMI滤波器。建立了电感、电容的高频等效电路,并分析了电感、电容随频率变化的特性曲线;通过分析传导干扰共模和差模的两种基本形式,建立了EMI滤波器相应的等效电路模型,并应用PSpice电路仿真软件分析了寄生参数对电磁干扰(Electromagnetic interference,EMI)滤波器插入损耗的影响。仿真结果表明,电感器高频等效并联电容(Equivalentparallel capacitor,EPC)、电容器高频等效串联电感(Equivalent parallel inductor,ESL)明显降低了EMI滤波器的高频插入损耗,为高性能滤波器的设计及插入损耗的计算提供重要的技术和数据参考。

High power density,high switching frequency and compact structure of switching power supply,put forward higher requirements for its electromagnetic compatibility.In order to design high-performance EMI filter,the high-frequency equivalent models of inductor and capacitor were set up,and the characteristic curves of inductor or capacitor with frequency were analyzed.The equivalent models of EMI filter,which were based on analyzing common mode and differential mode of the conduct interference were set up,and the influence of the parasitic parameter on insertion loss was analyzed with emulational software PSpice.The simulation results show that the equivalent parallel capacitance（EPC） of the inductors and the equivalent series inductance（ESL） of the capacitors decrease the insertion loss of EMI filter greatly,and provide important reference of technology and data for high-performance filters design and calculation of insertion loss.