A compact low inductance pulse energy driver system for pulse power applications

In recent years, there have been various developments of high-current discharge drivers used in pulsed-power technologies including linear transformer drivers and impedance-matching transformers. As the discharge current scales up, it becomes crucial to optimize the input energy requirements. A new system was designed to provide a scalable low inductance current driver suitable for pulse-power applications including z-pinch, plasma-focus, and other direct current drive applications. This paper explores the development of a new current driver for a system with a z-pinch load using six modular units of low inductance integrated multiple-capacitor assemblies developed by Specscan Sdn. Bhd. Each of these modular units comprise four folded aluminum foil and dielectric film capacitors arranged in a two-stage LC-inversion circuit. Six of these modular multi-capacitor assemblies were connected to a pair of hexagon-shaped transmission plates of 1 meter in diameter with a z-pinch load located in the center to form a voltage-discharge loop for an estimated loop circuit inductance of 6.31 nH. Six individual spark-gap switches were connected to the voltage inversion loops of the multi-capacitor assemblies. Voltages of +6.75 kV and −6.75 kV were applied across the switches to charge the capacitors requiring 280 J of total input energy. The switches were then triggered simultaneously to generate a voltage-inversion that provides a near-quadruple increase in voltage across the transmission plates to form a pulse-energy driver system. A peak voltage of approximately 24.4 kV was obtained at the z-pinch load with a peak current of 211 kA and a quarter-wave 10–90% rise time of 110 ns. The system generated 4.6 GW of peak power with a corresponding efficacy of 16.5 MW/J. This development illustrates a concept of an efficient scalable direct high current driver system for various pulse power applications using relatively low voltages. One particular interest in th- future is the possibility of scaling these drivers to operate in the megaamperes range. This can be achieved if: a) the charging voltages are increased; and b) if the transmission plates are enlarged to accommodate a greater number of modular multi-capacitor units. This paper will describe how the existing z-pinch system operates and the results obtained. Projections will then be made on its potential current scaling while maintaining its input energy efficiencies.