Prototype development progress toward a 500 kV solid state Marx modulator

Recent advances in IGBT and SiC technology have made possible a range of solid-state modulator concepts that were unthinkable a decade ago. Power densities and speeds of pulsed-power circuits have increased dramatically due to the commercial introduction of fast, multikilovolt IGBT silicon and SiC diodes featured in PCB-style packages. A solid-state modulator concept that stands to benefit considerably from recent IGBT and SiC breakthroughs is the Marx configuration-where an array of stacked modules generates high-voltage output pulses directly from a low voltage DC supply. The Marx scheme avoids the large, inefficient and costly magnetic cores inherent in standard modulator designs, resulting in a considerably simpler, cheaper and more compact mechanical solution. The main disadvantage to this approach is that the individual cells in a Marx bank must float at high voltages during the pulse, complicating the distribution of power and timing signals. This paper examines in closer detail the practical advantages and pitfalls of a solid-state Marx configuration, and explores a design approach with emphasis on performance, wall-plug efficiency, cost of manufacture, availability and ease of service. The paper presents electrical diagrams, mechanical CAD layout and preliminary prototype test data.