Optimum core dimension for minimizing proximity effect losses of an AC inductor for a galvanically isolated PV inverter

In this paper, it is shown how winding proximity effect losses in an existing AC inductor can be reduced without changing the actual winding. Instead, the core dimensions are changed with significant effects. For this purpose, Maxwell (ANSOFT) electromagnetic software package is used to investigate flux patterns and their influence on eddy current losses in the windings. Various core dimensions are analyzed with respect to flux patterns, and a design where the flux encloses a minimum number of winding layers is found. This significantly reduces the high frequency resistance of the windings up to 62.2% in comparison with the original design. The results are also explained in terms of the winding impedance matrix.