用于电磁干扰分析的共模扼流圈高频模型

共模扼流圈的高频特征极大地影响了电磁干扰（EMI）滤波器抑制传导EMI噪声的性能.为了准确地评估和预测EMI滤波器的性能，提出了一种基于150 kHz～30 MHz阻抗测量的共模扼流圈高频建模方法，建立了可用于EMI性能分析的差模模型和共模模型.采用Foster网络来表示共模模型参数随频率而变化的特征，并且通过一个实例给出了共模扼流圈的高频集总参数模型.通过比较共模扼流圈插入损耗的测量结果和仿真结果，证实了所提出的共模扼流圈高频建模方法的可行性.

High frequency modeling of common mode chokes for electromagnetic interference analysis

The high frequency parasitic parameters of common mode(CM) choke significantly influence the performance of electromagnetic interference(EMI) filter for conducted EMI suppression.In order to accurately estimate and predict the performance of EMI filter,a procedure was presented to build high frequency CM model and differential mode(DM) model for CM chokes from impedances measurement in the range of 150 kHz-30 MHz.Foster network was used to characterize the change of the parameters of CM model with frequency.As an example,lumped parameter high frequency CM and DM models were given,in which the parasitic parameters were described and determined based on the impedances measurement.The agreement of simulation and measurement results of the insertion loss of a prototype validated the modeling method.