电源EMI噪声源阻抗提取方法分析

Analysis of Power Converter EMI Noise Source Impedance

利用仿真计算的方法,分析了插入损耗与源阻抗幅值计算结果数值范围之间的关系,当插入损耗选择不当时,计算结果的数值范围将非常大,甚至可能大于100 dB。而当插入损耗为6~34 dB时,通常情况下可获得较小的源阻抗幅值范围。最后以标准信号源作为研究对象,进行了噪声源阻抗的提取,验证了此结论的准确性,为EMI滤波器设计提供理论依据。

In this paper,the relationship between the insertion loss and the numerical range of source impedance amplitude is analyzed by simulation.When the insertion loss is not properly,the numerical range of source impedance amplitude is very large,and may even be greater than 100 dB.A smaller range of source impedance can be obtained in most cases when the insertion loss is 6 to 34 dB.Finally,a 50Ωsignal generator is taken as the research object,the common-mode noise source impedance is extracted,which verifies the accuracy of the conclusion and provides theoretical basis for the design of EMI filter.