Dynamic Inductance Gradient Analysis of Series-Enhanced Four-Rail Electromagnetic Launcher

Abstract

To accurately describe the dynamic inductance gradient during the operation process of the series enhanced four-rail electromagnetic rail launcher, an equivalent geometric model based on skin depth is constructed. The influence of armature motion on current diffusion in the rail is considered, and the velocity skin effect is derived. Combined with Biot-Savart Law, an analytical calculation method for dynamic inductance gradient is proposed, and an experimental platform for the series-enhanced four-rail electromagnetic launcher is built, Calculate the dynamic inductance gradient of the experimental device and compare it with the eddy current field simulation calculation, demonstrating the correctness of the proposed analytical method for calculating the dynamic inductance gradient. Analyze the influence of armature motion on the system inductance gradient, and obtain that the initial velocity of armature launching is small, and the distribution of rail current is affected by the current skin effect and related to the current frequency. As the armature velocity increases, the distribution of current in the middle section of armature launching is affected by the velocity skin effect, The skin depth decreases and the dynamic inductance gradient decreases. As the armature speed increases, the dynamic inductance gradient gradually decreases and tends to stabilize in the accelerated stage of armature launching.

Keywords

• Electrical launching
• series-enhanced four-rail electromagnetic launcher
• dynamic inductance gradient
• velocity skin effect
• electromagnetic rail launcher velocity test
• B-dot probe