Electromagnetic Propulsion System with Rapid Current Discharge Circuit for Enhanced Projectile Acceleration

This paper presents a rapid current discharge circuit for single and multi-stage high current coilgun. The circuit eliminates an undesired braking force, which is developed due to a residual current, when the projectile passes the center point of an energized coil. This is done by rerouting the coil current towards an alternative, quick discharge path, where it is damped to zero. Utilization of the discharge circuit is especially advantageous in multi-stage coilgun systems, as the design of the discharge circuit is done once for the "worst case scenario" and applied to all the coils. It guarantees a safe operation of all the switches, with minor effect on the system performance. The discharge circuit operation has been validated by an experimental prototype rated for 450V, demonstrating rapid coil current discharge for braking force mitigation.