摘 要：随着电子电气设备运用的越来越频繁，电磁干扰成了人们关注的重点。电磁干扰给人们带来的损失越来越大，我们必须重视。本文介绍了电磁干扰在当今社会的时代背景，产生原因，以及可行的处理方式，着重介绍了电源EMI滤波器，提出了滤波器的架构以及损耗参数的测量，对于防止电磁干扰的研究具有一定意义。本文的重点是讲解了EMI滤波器的基本知识和基础功能，EMI噪声信号产生的原因，以及对于EMI噪声我们可以实施的处理方法，提出了以低通滤波器作为电源EMI滤波器的构想，并且详细分析了EMI滤波器中最为重要的插入损耗，文中应用网络理论分析了EMI电源滤波器的插入损耗与相关网络参量的关系，讨论了EMI电源滤波器的基本网络结构及其插入损耗的计算方法，建立了单相电源滤波器的共模及差模等效电路模型及滤波器件的高频分布参数模型。除此之外，本文详细介绍了二级LC滤波电路，完成了它的ADS 仿真，PCB 制做，以及实物制作。95058

毕业论文关键词：电磁干扰， 共模扼流圈 ，差模扼流圈 ，屏蔽 ，插入损耗

Abstract ：With the increasing use of electronic and electrical equipment, electromagnetic interference has become the focus of attention。 The loss of electromagnetic interference is more and more serious, we must pay attention to it。This paper introduces the cause of the electromagnetic interference in the background of current society, and the feasible way, and emphatically introduces the EMI power filter, is proposed to measure the structure and parameters of the filter loss, has a certain significance for the research of preventing electromagnetic interference。The focus of this paper is to explain the basic knowledge and basic function of EMI filter, EMI noise, and noise processing method for the EMI we can carry out, put forward to the idea of a low pass filter as EMI power filter, and a detailed analysis of the most important insertion loss EMI filter, the application of network theory this paper analyzes the relationship between the insertion loss and the relevant network parameters of EMI power filter, discusses the calculation method of the basic network structure of EMI power filter and its insertion loss, high frequency distribution parameter model is established common mode single-phase power filter and difference model and filter mode equivalent circuit。 In addition, this paper introduces the two stage LC filter circuit, completed its ADS simulation, PCB system, as well as physical production。

Key words: electromagnetic interference，  common mode choke ， differential mode choke ，insertion loss

目录

1 前言 1

1。1 研究背景及其意义 1

1。2 国内外研究现状 2

1。3 本文的主要工作 2

1。4 本文的设计任务 3

2  电源EMI滤波器的设计原则 3

2。1 电源EMI滤波器 3

2。2 EMI信号类型及特点 8

2。2。1  EMI噪声的产生原因 8

2。2。2 典型的干扰传输途径 8

2。2。3  处理办法 8

2。4  电源EMI滤波器插入损耗的计算方法 9

2。4。1  二端口网络 9

2。4。2 电源EMI滤波器插入损耗 10

2。5高频特性 12