Dynamic Simulation and Optimization Design of Helical Coil Electromagnetic Launcher

The research object of this article is a helical coil electromagnetic launcher (HEML) with dual driving coils. According to the contact between the brush and the stator coil, the launch process is divided into three stages. The Ayrton arc model is introduced to provide the governing equations of each stage, and then, an entire transient launch model is established. Subsequently, based on the geometric mean distance principle and the equivalent circular loop method, Neumann’s formula is extended to calculate the self-inductance and mutual inductance of rectangular cross section coils. Combined with the thin-walled cylinder theory, the analytical expression for the electromagnetic stress of coils is derived. The electromagnetic-structure coupling simulation verifies its accuracy, with a relative error of 2.8%. The maximum stress appears in the last turn of the stator coil. Finally, the particle swarm optimization algorithm with linearly decreasing inertia weight (PSO-W) is applied to optimize the coils’ structure parameters with the goal of the system’s launch efficiency. The results indicate that increasing the wire’s cross-sectional area, increasing the radius of the coil, and reducing the turn spacing all contribute to the system’s launch efficiency. Meanwhile, it was found that due to 50% of the energy being lost in arcs, the launch efficiency is only 31.13%. The above results are helpful for the structure design and application of HEMLs.