屏蔽腔内任意高度线缆端接TVS管电路的电磁耦合时域分析

Time Domain Coupling Analysis for the Arbitrary Height Cable Terminated with TVS Circuit in Shield Cavity

该文基于时域有限差分(FDTD)方法和传输线方程,结合插值技术和牛顿迭代法,提出一种新的时域混合算法,能够快速模拟屏蔽腔内任意高度线缆端接瞬态电压抑制(TVS)管电路的电磁耦合问题,并实现空间电磁场与线缆和电路瞬态响应的同步计算。该算法首先利用FDTD方法结合STL网格剖分技术实现屏蔽腔结构的快速建模以及腔体内空间电磁场分布的准确模拟。然后利用传输线方程结合插值技术建立腔体内线缆的场线耦合模型,结合FDTD方法,迭代求解出线缆上的电压和电流响应。对于线缆端接的TVS管电路,列写电压电流方程,采用牛顿迭代法计算得到电路端口的电压响应。通过与电磁仿真软件的计算结果进行对比,验证了所提时域混合算法的正确性。研究表明,该算法能够很好地应用于屏蔽腔内线缆端接负载的TVS管限幅防护设计。

This paper presents a novel time domain hybrid method consisting of Finite Difference Time Domain （FDTD） method, Transmission Line （TL） equation, interpolation technique, and Newton iteration method for the coupling simulation of the arbitrary height cable terminated with TVS circuit in shield cavity rapidly. It can achieve a strong synergism computation of electromagnetic field and the responses of the cable and the circuit. The hybrid method uses FDTD method combined with the STL mesh generator technique to model the enclosure of the cavity rapidly and simulate the electromagnetic field distribution in the cavity accurately. The TL equation with interpolation technique is used to set up the coupling model of the cable in the cavity. Then the FDTD method is used to discrete the TL equation to obtain the transient voltage and current responses on the cable. The current-voltage equations are used for the analysis of the TVS circuit. Then the Newton iteration method is utilized to solve the current-voltage equations to obtain the voltage responses on the TVS. The correctness of the hybrid method is confirmed by comparing with the results obtained by electromagnetic simulation software. In testing, the hybrid method can be well applied to the limiting protection design of the loads in the terminal of the cable in shield cavity.