The design and optimization of a power supply for a one-meter electromagnetic railgun

Abstract

A naval electromagnetic railgun would be a considerable asset against a littoral environment. By accelerating projectiles to 3 km/s, a naval railgun would be capable of reaching 300-400 nautical miles. Problems such as rail erosion, energy storage and fire control prevent the railgun from becoming a weapon to date. At the Naval Postgraduate School, the Physics Department continues to investigate and develop concepts to overcome these challenges. As part of the methodology, previous students built a one-meter railgun system for experimentation. The existing 1.6 mF power supply is insufficient to fire this railgun effectively. To design a sufficient power supply a MATLAB code was created to simulate a generated current pulse and to predict the subsequent railgun performance. Interrelated factors such as railgun geometry, muzzle velocity, current density and contact surface area were taken into consideration. Also, tradeoffs in capacitance, projectile mass and residual current were weighed against one another to achieve desired railgun performances. From numerous simulations, this study determined that the one-meter railgun with a 21.5 mF power supply could fire a 0.158-kg projectile at a velocity of 1 km/s, and leave a residual current of only 4% of the initial energy once the projectile exits the rails. v.