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.