二端口网络散射参数理论及其在平面EMI滤波器测试中的应用  

Theory of Scatter Parameters of Two Port Network and Its Application in the Test of Planar EMI Filter

作　　者：石磊磊[1] 王世山[1] 徐晨琛[1] 

机构地区：[1]南京航空航天大学江苏省新能源发电与电能变换重点实验室,南京210016

出　　处：《电工技术学报》2013年第2期78-85,共8页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金(51177071);航空基金(20100852008)资助项目

摘　　要：EMI滤波器以其抑制开关电源中传导电磁干扰的有效性而得到越来越多的重视。相比于分立元件构成的滤波器,平面EMI滤波器拥有整体体积小、高频性能好等优点。但是现有的方法尚不能精确的预测其在实际电源系统中工作特性。本文提出采用散射参数法测量平面滤波器特性:分析推导了EMI滤波器散射参数与EMI滤波器插入增益的函数关系,提出预测不同的外部阻抗条件下EMI滤波器插入增益的方法;建立平面滤波器近场耦合模型,利用散射参数与阻抗参数关系,提出近场耦合模型中互感提取方法;完成一台平面EMI滤波器样机,对其不同阻抗条件下的插入增益特性进行了理论计算与实际测量,同时推导其差模结构的近场耦合模型并计算模型在标准阻抗条件下的插入增益,与实际测量进行比较,验证了理论的可行性。EMI filter plays an important role in restraining conducted EMI. Planar EMI filter has a decreased size and high reliability in high frequency performance compared to passive discrete EMI filter. However, the performance of EMI filter cannot be exactly expected using existing methods. Therefore, the method of scatter parameters is used to measure EMI filter performance in this paper. The relationship between scatter parameter and insertion gain of EMI filter is derived; the method to predict the insertion gain of filter under different impedance is proposed. The near field coupling model of the planar filter in high frequency is deduced. Based on the relationship of scattering parameters and impedance parameters relations, the method to extract the mutual inductance in the near field is proposed. A sample planar EMI filter is completed. The theoretical calculation and practical measurement under different impedance condi.tions of the insertion gain are completed. At the same time, the differential structure of the near field coupling model is deduced and the insertion gain in standard impedance conditions is calculated, and compared with the actual measurements. The feasibility of the theory is verified.

关 键 词：平面EMI滤波器 散射参数 插入增益 近场耦合 

分 类 号：TM713[电气工程—电力系统及自动化]