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In gapped inductors, the fringing field of the air gaps causes additional eddy current losses in the windings and an increase of the inductance. Since this impact of the fringing field is very significant, calculating the additional eddy current losses and the inductance increase is important in the design of inductors. This article proposes analytical formulas to accurately calculate the inductance and the additional eddy current losses in gapped inductors with solid round wire and Litz wire windings. The analytical formulas are verified by measurements, showing that the proposed models are accurate over a wide-frequency range. [ABSTRACT FROM AUTHOR]

For comprehensively optimizing high-frequency foil inductors, calculating the increased inductance and the additional eddy current losses due to a two-dimensional magnetic fringing field caused by air gaps in the center leg is mandatory. This article proposes an analytical model that accurately calculates the inductance and the additional eddy current losses in gapped inductors with foil windings. The analytical field expressions are combined into closed-form winding loss and inductance formulas and verified by measurements. Furthermore, the frequency dependency of the inductance due to the shielding effect of the foil conductors is being discussed. [ABSTRACT FROM AUTHOR]

In this paper, the design procedure of a 14.4 kV output voltage, 100 kHz transformer with an isolation voltage of 115 kV using Litz wire is presented. All design models, including a generalized magnetic model for the leakage and the loss calculations as well as an electrical model for the parasitic capacitance estimation for the transformer are derived and proven by measurements. For designing the insulation, a comprehensive design method based on an analytical maximum electrical field evaluation and an electrical field conform design is used. The resulting design is verified by long and short term partial discharge measurements on a prototype transformer. [ABSTRACT FROM AUTHOR]