Research On The Electromagnetic Topology Analysis Method Of The Whole System Excited By EMP

The electromagnetic topology(EMT)method is a traditional method to study the interaction between high-altitude electromagnetic pulse(HEMP)and electronic system.In a historical period of limited computer software and hardware,the electronic system can be ed into a simple electromagnetic interference propagation network under the good shielding approximation(GSA)principle,and the HEMP response on network nodes can be solved by BLT equation.Based on the multi-conductor transmission line(MTL)algorithm,BLT equation is a one-dimensional equation in space,which is equivalent to simplifying three-dimensional electromagnetic coupling problem into one-dimensional problem.In the aspect of whole system modeling,the original EMT method does not fully consider the influence of three-dimensional metal structure,and there is obvious simplification.In order to improve the accuracy of the whole system electromagnetic model,the finite difference time domain(FDTD)method and MTL algorithm are introduced under the basic framework of EMT,and the modified FDTD oblique wire algorithm proposed in this thesis is used to effectively fuse the two dimensional algorithms.The main structure that HEMP can act on in the whole system is decomposed into part structures that FDTD method and MTL method can simulate.HEMP simulator is decomposed into various rule structures that FDTD method can model,and the whole system 3D EMT analysis platform under HEMP simulator is gradually established.The main achievements of this thesis are as follows:1.Study the FDTD modeling method of various regular structures,further modify the FDTD model of oblique wire which is not parallel to the coordinate axis,and complete the modeling program.Regular block structure and wire structure are the basic structures to build the simulation model of HEMP simulator.The corresponding structures can be generated by calling subroutines with input parameters in the program,which are the foundation for modeling and simulation of various HEMP simulators.2.The comprehensive simulation methods of various composite structures are studied,and the effective integration of 3D FDTD method and MTL method is preliminarily realized by using the modified FDTD oblique wire algorithm The problems of algorithm association and time synchronization are solved,and the experimental verification is carried out.The composite structure comes from the transition and conversion structure of the whole system.There are some structures that need to adopt 3D electromagnetic simulation method,and some structures need to adopt one-dimensional electromagnetic simulation method.Therefore,different algorithms need to be integrated.3.The FDTD modeling method based on the CAD model of the tested equipment is studied;' and the modeling program is completed.The shell structure of the tested equipment is often irregular.In order to construct the corresponding FDTD calculation model,it is necessary to read the accurate geometric structure data from the CAD model,mark the 3D mesh within the geometric boundary,and associate the difference formula of the corresponding material.4.The modeling and simulation methods of various HEMP simulators are studied and the problem of effective splicing of multiple regular structures is solved Some simulation results are compared with the experimental results The simulation model of HEMP simulator is the excitation source of EMT analysis platform,which can match the HEMP test well,and is conducive to the verification of test results and simulation results It can also provide simulation analysis data for the design of HEMP simulator.5.Construct the 3D EMT analysis simulation platform based on the CAD model of the tested equipment under HEMP simulator,and complete the comprehensive program.The platform can solve the problem of effective integration of different modeling methods and different structural algorithms The generated calculation model can remove the non-conductive structure in CAD model and can construct the cable network topology structure Moreover,the position and angle of the analysis object under the HEMP simulator can be precisely adjusted.