Power conditioning for high voltage pulse applications

This dissertation addresses advances in power conditioning for high voltage pulse applications. In particular an opening switch based on exploding wire technology for inductive energy storage systems, and a rapid capacitor charger for compact marx-generators are discussed. The first section about the exploding wire-fuse opening switch presents basic fuse sizing rules for various fuse materials as well as for a variety of primary energy sources. The basic mechanisms of wire explosion are discussed and a new method to determine the optimum fuse material is proposed. To aid the simulation of circuits involving exploding wires a phenomenological fuse resistance model is presented and a number of results of real data and simulation data are given. Furthermore, a literature survey of a number of important material properties as well as for the integral of current action is presented. Concluding the first section is a discussion of an aqueous-electrolyte load, which also presents resistivity/concentration formulae. The second section of this dissertations concentrates on the rapid capacitor charger developed at the Center for Pulsed Power and Power Electronics at Texas Tech University. Basic charging mechanisms are discussed with an emphasis on capacitor charging utilizing hard switching technology. The basic building blocks of the capacitor charger, the low-inductance bus bar with the H-bridge inverter, the controller with an HC12 microprocessor, the high-voltage multi-tap step-up transformer, and the multi-tap full-bridge rectifier are addressed. Tools are provided to estimate optimum frequency, optimum primary turns, and volume for an e-core type transformer in pulse environments. Furthermore, a thermal model for the employed IGBTs is presented to address junction temperature concerns. The implementation of the HC12 microprocessor is addressed and discusses the basic charging principle and, in addition, its assembler-code representation. The impact of different charging-functions like constant, linear, or exponential charging is presented in a number of detailed graphs, including DC-bus voltage, transformer input current, capacitor input current, and capacitor voltage. Concluding the section about the rapid capacitor charger is a presentation of a complete PSpice system model including the DC-bus voltage swing, the switch junction temperature, the non-ideal transformer, and an arbitrary duty-cycle function.