Selection of Stator Wire Diameter for High Current Helical Flux Compression Generator

Helical flux compression generators (HFCGs) are powerful high current source for pulse power applications. These HFCGs utilise the energy stored in the high explosive to compress the magnetic flux between the metallic conductor and surrounding stator which results in amplification of current. Due to single shot nature of HFCG's electrical output reproducibility is of great importance. Current gain of HFCG's depends exponentially on the generator inductance and resistance. However for the designed generator inductance, wire diameter dictates the gain as it affects the series resistance. Moreover, resistivity of the conductor also changes because of the ohmic heating of conductor and diffusion of the magnetic flux into the conductor which reduces the current gain of HFCGs. A software model has been developed in house and implemented in Matlab-Simulink to simulate helical FCG. Simulations have been performed in order to select the appropriate stator conductor diameter for the reduction of the losses within the confined volume and to study the effect of change in the resistance of stator wire conductor with temperature. Helical flux compression generator with constant pitch and an overall length of 600 mm has been chosen for study, and its performance is analysed for different wire diameters. A minimum diameter of wire has been predicted for desired output current which does not affect the performance of HFCG.