Ineroduction 滤波器基础知识

--Our EMI filter are designed on the basis of IEC939-1、IEC939-2、EN13300、EN133200 and UL1283、

GB/T15287-1994、GB/T15288-1994 Standards. Our filter are the low-pass filter composed by the passive components

(L、C、R)and adopt the impedance  mismatch theory between filter and access port.

本公司产品符合IEC939-1、IEC939-2、EN13300、EN133200以及UL1283、GB/T15287-1994、GB/T15288-1994标准.

本手册涉及的电源滤波器由无源元件（L、C、R）组成低通滤波器，含有共模和差模衰减网络；采用了滤波器与接入

端的阻抗失配原理.滤波范围在10KHz~30MHz，能有效抑制沿电源线传导的EMI干扰。

General circuit configuration 阻抗搭配

Customers choose their own devices in the power filter, the device should be based on their actual

interference situation combined with power filter works to choose. Mains filter works by using an impedance mismatchat

both ends of the principle to work, so customers in the choice of power supply filter should refer to the principles

ofthe Fig.1, the only way to maximize the power supply filter filtering effect, to meet your requirements.

客户在选择适合自己设备使用的电源滤波器时，应该根据自己设备的实际干扰状况结合电源滤波器的工作原理进行选择.

电源滤波器的工作原理是利用两端的阻抗失配原理进行工作的，所以客户在选择电源滤波器时应参照图1所列的原则进行，只有这样才能最大限度的发挥电源滤波器的滤波效果，以达到满足您的要求。

Fig.1

Fig.2

* △FILTER: 3 phase power system without a Neutral phase is*  Y FILTER: 3 phase power system have a Neutral line called Y filter .

Leakage current: 泄露电流

Single-phase leakage-current measurement circuits

--单相漏电流测试原理图

Filter internded for connection to a 2 wire power supply

滤波器用于连接一个2线供电

Filter intended for connection to a 3 wire power supply，ground neutral

power supply 滤波器用于连接一个3线供电,中线接地电源

Three-phase leakage-current measurement circuit

--三相漏电流测试原理图

INSERTION  LOSS(IL)插入损耗

The insertion loss is measured according to CISPR 17. In most cases, published insertion loss data assumes that

power line and load have the same impedance and all such data are in practice generated form 50Ω test system.The best way to verity actual effectiveness in noise suppression is to mount the filter in the equipment to test the conducted emission in a shield room.

插入损耗的测试方法在CISPR17中有详细规定，产品样本上提供的插入损耗曲线是在50Ω系统上测试得出，即假定电源和负载的输入、输出两侧都是50Ω。但是，选用滤波器的最佳方法是将它接入使用设备在屏蔽房中进行实际测试。

Insertion loss i composed of common mode and differential mode insertion loss, and the test measurement circuit:插入损耗由共模和差模插入损耗组成，测试原理图如下：

Common mode 共模

Differention mode 差模