非线性负载简化模型及其应用

为实现复杂网络电磁脉冲(electromagnetic pulse, EMP)耦合分析,针对非线性负载引起的分析效率和收敛性问题,提出了非线性负载精简建模方法,即将多项式表示的非线性关系用压控元件代替,指定器件动作时间表示开关响应时间,忽略温度等不必要参数,减少模型元器件个数等.采用该方法建立了气体放电管(gas discharge tube,GDT)和金属氧化物变阻器(metal oxide varistors,MOV)的精简SPICE(simulation program with integrated circuit emphasis)模型,并且用3种不同类型的脉冲激励端接非线性负载的传输线,进行了收敛性和仿真效率分析.结果表明,GDT和MOV的简化模型能够很好收敛,MOV的模型分析效率提高约30%,GDT的模型分析效率稍有劣化,但完全避免了理想开关元器件的使用,与实际器件的工作原理一致.这些建模方法具有较强的普适性,可以移植到其他非线性负载的建模上,例如与线缆耦合的精简计算模型相结合,从而提高超大系统的电磁兼容(electromagnetic compatibility,EMC)设计与评估效率.

Reduced model and its application of nonlinear loads

For the realization of the large-scale complex networks electromagnetic pulse (EMP) coupling analysis, the reduced modeling method of nonlinear loads is proposed, in view of the typical nonlinear load efficiency and convergence. The nonlinear polynomial relationship is replaced by the controlled voltage source; the response time of nonlinear loads is specified. Some parameters such as temperature are ignored, and the number of model components is reduced. The reduced SPICE model of gas discharge tube (GDT) and metal oxide varistors (MOV) are established. With EMP excitation of three types, the transmission line ended by the two nonlinear loads is analyzed for the convergence and the simulation efficiency. The results show that the MOV model and the GDT model can reach well converge. Computational efficiency of the MOV model is improved by 30%. The GDT model completely avoids using the ideal switch components, so slight efficiency degradation is acceptable. These modeling methods have strong universality and can be transplanted to other nonlinear load modeling. It improves the reduced calculation model of cable coupling, and is of great practical significance for improving the EMC design and evaluation efficiency of super-large systems.