Setup of a 500kJ Compact Pulse Forming Network used for EMG Investigation

Abstract

The Electromagnetic gun (EMG) system needs a compact pulsed power supply system, which should supply high energy and large current. The paper presents a setup of a compact pulsed power supply system used for EMG system, which is based on high energy density capacitors. The pulse forming network consist of ten 50 kJ modules, which can be triggered in sequence. Each module is composed of a high energy pulsed capacitor (592 muF/13 kV), a triggered vacuum switch, a pulse shaping inductor (20 muH), a crowbar and a dump resistor(30 mOmega). The amplitude of the output current of one module is 70 kA. In the module, the triggered vacuum switch is quite compact and can be triggered precisely. The crowbar, consisting of high pulse-current diode-stacks connected in series, prevents the capacitor from recharging with reverse voltage. The requirements for the diode-stacks are fast-recovery time, high voltage withstand ability and large current capability. A proper protection measure is used in order to protect the crowbar diodes from the damage of over-voltages when switch is fired. At last, a proper discharge current waveform of ten modules triggered in sequence is provided.