Analysis of Transient Characteristics of Electromagnetic Launchers Using Analytical Method

The working condition of high-speed and high-current sliding electrical contact is unique to the electromagnetic launcher. Under such an extreme condition, the transient characteristics of the launching process can be analyzed with several special finite-element programs, but it is quite time-consuming. Therefore, a more efficient simulation method for current diffusion in the launching process was proposed in this article. First, an analytical expression of the current density distribution of the rails was established through the method of separation of variables, and the undetermined coefficients in the expression were obtained based on the finite-element calculation results and particle swarm optimization algorithm. Then, a model of segmented rails was built, and the excitation current in the segmented rails was processed through the time–frequency analysis method to simulate the velocity skin effect. The electromagnetic field distribution and the transient impedance parameters of the rails during the launching process were obtained based on the 2-D current density analytical expression and the segmented rails model. The effectiveness of the proposed method was verified by comparing with the results of finite-element method (FEM) simulation and launch experiment.