A Fast and Accurate Method for Calculating the Mutual Inductance of Coilgun Based on Current Filament Model

The current filament method (CFM) is a widely used and efficient approach for simulating coilgun systems, but its accuracy is highly sensitive to the precision of mutual inductance calculations. This article presents a novel method for calculating mutual inductance, in which the positions of the equivalent cells in the driving coil are determined by Gauss–Legendre quadrature points, replacing the conventional uniform cell distribution. This approach achieves a high convergence order, maintaining high accuracy with fewer cells. Furthermore, leveraging the structural and motion characteristics of the coilgun, a physics-driven search algorithm is developed to automatically determine the near-optimal number of Gaussian points for different coils, thereby eliminating the need for cumbersome manual adjustments. The proposed method and the search algorithm exhibit a strong synergistic effect: the higher error-convergence order of the proposed method significantly reduces the search domain and accelerates convergence compared with the original method.