Influence of air-gap length and cross-section on magnetic circuit parameters

Air-gap is one of the most crucial part of magnetic circuits, especially in high power inductors. It significantly modifies parameters of magnetic devices by increasing of saturation current, linearizes B-H curve of magnetic circuit and causes decreasing of the inductance. Therefore, the optimal selection of a shape and dimensions of air-gap is very important from designing point of view. This paper is focused on the presentation of optimal dimensions of the air-gap with rectangular cross-section as a function of air-gap length and cross-section ratio. The COMSOL Multiphysics® software was used for simulation of the magnetic field distribution for chosen cases in the exemplary magnetic circuit. The AC/DC module was applied for the calculations. By varying of the geometry parameters optimal solutions for this kind of magnetic circuit are concluded. The presented results are dedicated to magnetic designers to prepare inductor cores designs optimally.