Experimental Results of a High Voltage Wideband Load Driven by a Pulse Transformer and Opening Switch Power Conditioning System

As a part of the University Consortium for high power microwave integration, the University of Missouri-Columbia concentrated on the development and testing of a flux compression generator simulator, non-magnetic core spiral-strip pulse transformers, and exploding wire fuses. Additionally, an oscillator, consisting of a tri-plate high voltage capacitor and shunt inductor, was built and tested as a prototype system load. The effectiveness of the prototype load as a hyperband oscillator in initial experiments and its relative simplicity prompted further investigation of a second generation prototype. The low inductance, high voltage capacitor has been redesigned from a tri-plate geometry to a cylindrical geometry. The diameter of the capacitor is less than 15.24 cm, which fits the capacitor within the same size constraints as the pulse transformer and exploding wire fuse. The capacitance of the new high voltage capacitor is designed to be several hundred picofarads, more than double that of the first prototype. The dramatically reduced capacitor volume results in an overall energy density increase. The capacitor design and construction was adapted from the methods used for the spiral-strip pulse transformer, which also has a cylindrical form and has previously been successful in holding off high voltage gradients. While testing the new low inductance, high voltage capacitor with the full power conditioning system, the system was driven by a much lower current source to reduce excess input energy without significant sacrifice to peak load voltages. The ability of the power conditioning system to achieve capacitor load voltages on the order of hundreds of kilovolts with much smaller inductively-stored energies demonstrates the system's compatibility with both smaller flux compression generators and other current sources. This paper describes the design and construction methods of the new RF load oscillator and the scaling of the system input energy. The experimental results are reported of the full power conditioning system and load driven by the simulator of a flux compression generator. Three modes of operation are discussed.