Rapid charging seed source with integrated fire set for flux compression generator applications

The design and testing of an integrated front-end power and control system for helical flux compression generators (HFCG) is presented. A current up to 12 kiloamps needs to be pushed into the 5.8 microhenry field coil of the HFCG to establish the necessary seed flux for generator operation. This current is created with the discharge of a 5 kilovolt, 50 microfarad metalized polypropylene film capacitor using a single-use semiconductor closing switch. Once peak current/flux is obtained in the seed coil an exploding bridge wire (EBW) detonator is initiated with a discharge from a 1 kilovolt, 500 millijoule capacitor array contained in the compact fire set. Both capacitances, seed and fire set, are charged using a rapid capacitor charger system. The rapid capacitor charger is a solid state step up converter supplied by lithium-ion polymer (LiPo) batteries. It provides the 5 kilovolts and 1 kilovolt dual output voltages required for the compact seed source and compact fire set, respectively. The rapid capacitor charger operates at an average output power of 3 kilowatts and charges both capacitances simultaneously in under 250 milliseconds. The rapid capacitor charger is reusable if protected from the explosive detonation. All components in the system are fiber-optically controlled by a battery powered microcontroller that is fully optically isolated from the system. This controller provides the precise timing required to maximize performance of the HFCG system. The entire front-end system including batteries, capacitors, power electronics and control circuitry but excluding the HFCG occupies a volume of less than 4 L and fits in a 15 cm diameter package.