A Multi-Excited Electromagnetic Coilgun Using Split Drive Coils

Coilguns offer an exciting option for achieving hypervelocity ( $\geq 3$ km/s) launching systems. However, they suffer from low efficiency due to poor coupling between the projectile and the drive coils. The drive coils and the projectile must also sustain high thermal and mechanical stresses. Although, the drive coils can be reinforced to sustain such stress, it is difficult to design the projectile in most of the cases. Therefore, it is imperative to design the coilgun launching system to reduce the thermal and mechanical stresses on the system in addition to achieving higher efficiency. In this work, the authors propose a novel design of an induction coilgun system named as the split drive coilgun. The authors have split the drive coil of the conventional coilgun into inner and outer drive coils. In addition to achieving a higher efficiency and projectile muzzle velocity, the proposed design presents a reduced thermal and mechanical stresses on the system. The authors have compared the conventional coilgun launching system with the split drive coilgun on several performance parameters. In addition, this article also presents simulation results using the current filament method for both systems along with their experimental validation.