INVESTIGATION OF A HIGH VOLTAGE, HIGH FREQUENCY POWER CONDITIONING SYSTEM FOR USE WITH FLUX COMPRESSION GENERATORS

摘要

The University of Missouri-Columbia is developing a compact pulsed power system to condition the high current signal from a flux compression generator (FCG) to the high voltage, high frequency signal required for many pulsed power applications. The system consists of a non-magnetic core, spiral-wound transformer, series exploding wire fuse, and an oscillating mesoband source. The flux compression generator is being built by Texas Tech Univ. and is designed to drive inductive loads on the order of microhenries rather than a nanohenry load often driven by FCGs. The power conditioning transformer consists of a 1 μH primary winding inductance and a turns ratio of 1:3 with a coupling factor between .75 and .85. Use of the transformer and a crowbar switch to minimize the peak voltage across the fuse allows the fuse length to be reduced without risk of an arc breakdown. The fuse was designed to interrupt a peak current of 25 kA - 40 kA in less than 500 ns. The multiple stage fuse is constructed using two sections with an effective length of less than 25 cm. A capacitance of about 275 pF connected to the transformer secondary is charged to a voltage around 200 kV. The capacitor is then switched into an underdamped resonant circuit to generate an RF signal. A non-destructive test stand has been built to simulate the output current of a flux compression generator and allow inexpensive and repeatable testing of the power conditioning components. This paper includes a description of the test stand, pulse transformer, exploding wire fuse, and oscillating circuit along with experimental results obtained with the non-destructive test stand.