线缆集总等效电磁干扰源测量模型研究

Research on Measurement Model of Lumped Equivalent Sources of Electromagnetic Interference

复杂电磁场激励下线缆终端的响应很难通过数值计算的方法准确获得。基于场线耦合理论,提出了线缆的集总等效电磁干扰源的测量模型。根据集总等效源与终端负载无关的性质,得到这一激励下的线缆终端的集总等效源,为分析和研究相同外场激励不同终端负载下的终端响应提供了条件。利用两线架空线模型,通过理论分析验证了该模型的有效性,并研究了终端含有动态元件网络的电磁干扰问题,该模型分析结果与时域有限差分法得到的瞬态时域结果波形和幅值均一致。应用该方法获得了两线串扰问题的集总等效源,并通过计算获得了不同端部负载下的电压响应,计算结果与实验结果误差≤8%。准确地获得电磁干扰等效源,通过建立抑制元件的宽频模型,可以系统地研究抑制措施的抑制效能。

The terminal responses of cables under the electromagnetic field are difficult to obtain using the method of numerical method. Using the transmission line theory, we put forward a measurement model of the lumped equivalent source. Depended on the nature that the lumped equivalent source is independent of the terminal load and the lumped source is the same for the different terminal loads under the identical incident field, the lumped equivalent sources are ob- tained, and the terminal responses can be researched under different terminal load. The weak coupling crosstalk model based on two lines above the common ground is built, and the validity of the model is verified by numerical simulation. The EMI problem that the terminal network contains dynamic element is studied using this method, the transient wave shape and the magnitude are the same as the result obtained by the Finite-Difference Time-Domain method. The lumped sources are obtained for the crosstalk problem contained two lines, moreover, by using these sources, the responses are calculated under different terminal load. The error between calculation result and experimental result is less than 8%. Af- ter obtaining the accurate electromagnetic interference lumped source as well as building the broadband frequency model of suppression elements, the effect of electromagnetic interference and the performance of suppression measures can be researched systematically.