Investigation On Electromagnetic Pulse Simulator And Its Control

A practical electronic system is located within a metal shield cavity with unavoidable perforated apertures and conducting wires pass through the enclosure. Through an aperture and wires external electromagnetic pulse couples to the cavity, in which the transient current is induced on the lines and the transient voltage is induced on the line ends, and the interference formed by the transient current and voltage has destructive effect. An electromagnetic pulse simulator, acting as the external high power electromagnetic pulse of the aperture coupling electromagnetic topological model, offers necessary technical support for the experimental research on the complicated electromagnetic interaction circumstance.The electromagnetic pulse simulator consists of a pulse source, the front triangular plates, the middle flat plates, the back triangular plates and a load matching resistance, respectively. The pulse source consists of five capacitors with 50kV voltage. The transverse electromagnetic (TEM) wave can be produced between the middle flat plates by releasing the stored electric energy of the capacitors through the load matching resistance. In this dissertation, the digital signal processor(DSP)has been used to control the electromagnetic pulse simulator,with the C programming language, the adjustable continuous pulse waves of double exponential have been obtained and the adjustable scope is the pulse inerval greater than 15ms, the voltage amplitude less than 50kV.Since the pulse source has a strong impact on the electromagnetic pulse simulator characteristic, state space methd is used to analyze the discharge circuit of the pulse source, the first-order linear differential equations of the voltage and current varibles have been derived, with the Matlab software, the soultion has been obtained in time domain. The detailed design scheme for reducing pulse wave rising time has been put forward in this dissertation.On the basis of consulting a large number of documents, the electromagnetic field analytic expression of the simulator work volume is derived from the electromagnetic field tensor. The computation result indicates that electromagnetic field distribution results from different retard potentials superimposed by the uniform currents from the front and back conical plates as well as middle parallel plates, and the field distribution has the feature of transverse electromagnetic(TEM) waves. To verify the effectivity and validity of the fields analytic expression in time domain, the measured electric field within the simulator work volume has been taken by using a dipole sensor.Through the comparison of the actual measured values and the theoretic calculation values, the results indicate that theoretic calculation values are in good agreememt with measurements, so the analytic expression can be applied to the electromagnetic effect analysis of electronic system and its predictive study,and the analytic expression also provides the foundation for further calculation of the electromagnetic fields in the complex electromagnetic circumstance.