Power Supply Options for a Naval Railgun

Abstract

Large railguns require powerful power supply units. At the French-German Research Institute of Saint-Louis (ISL), most experimental railguns are driven by power supply units based on capacitors. Recent investigations at ISL explore the possibility to use coil-based systems to increase the energy density and reduce the footprint of the power supply. In this paper, an electrical circuit simulation is used to investigate the difference for railgun operation in between a capacitor and a coil-based power supply with respect to the current amplitude behavior, projectile velocity, and launch efficiency. For this, a scenario of a 25-MJ muzzle energy railgun is simulated with two different power supply options; one is based on capacitors, and the other is on coils. The circuit resistance determines a large part of the losses of the system and therefore defines the efficiency of the launch and the size of the power supply. Therefore, a range of different resistances were simulated as well. The interpretation of the results of the performed simulations leads to the conclusion that the capacitor-based system “naturally” produces a favorable current pulse trace with respect to launching a mechanical delicate payload. Further simulations show that the disadvantage of the inductor-based supply can be mitigated by increasing the power supply unit subdivision into smaller units.