基于时域测量的传导电磁干扰分离技术与实现

Separation Technology and Implementation of Conducted EMI Based on Time Domain Measurement

电磁干扰通常分为差模干扰和共模干扰EMI滤波器是抑制系统传导电磁千扰的有效方法,因此在设计EMI滤波器时需要分为差模和共模两个方向进行专门设计目前,国际上规定的传导电磁干扰测量设备为线性阻抗稳定网络,其所测量得到的是差模和共模的汇合信号。因此,将所测得的噪声信号分离为差模和共模信号是抑制电磁干扰首先要解决的问题。根据电磁干扰的形成机理,通过对线性阻抗稳定网络输出信号进行时域采样,使用数值计算方法实现了传导电磁干扰的全软件分离和频谱输出。该方法实现了传导电磁干扰信号的全软件分离,无需单模分离网络,且不存在半软分离方法的测量同步难题:试验表明,该方法在现场传导电磁干扰测试排查工作中具有较高的实用价值。

Electromagnetic interference is usually divided into differential mode interference and common mode interference.EMI filter is the effective way to suppress conducted electromagnetic interference in the system.Therefore,in the design of EMI filter,it needs to be designed specially in two directions of differential mode and common mode.At present,linear impedance stabilization network is adopted internationally as the measurement equipment of conducted electromagnetic interference,which measures the confluence signals of differential mode and common mode.Therefore,the first problem to be solved is to separate the measured noise signal into differential mode and common mode.According to the formation mechanism of electromagnetic interference,through the time domain sampling of the output signals of the linear impedance stabilization network,the numerical calculation method is used to achieve the full software separation of the conducted electromagnetic interference and the spectral output.This method realizes the full software separation of the conducted electromagnetic interference signal,without the need for single mode spearated network,and there is no measurement synchronization problem of semi-soft separation method.Experiments show that this method has high practical value in the field conducted electromagnetic interference test sand troubleshooting.