Modeling of Frequency-Dependent Winding Losses in Solid and Litz-wire Toroidal Inductors

This paper has investigated a method for modeling the frequency-dependent winding losses of toroidal inductors which can be used in power electronics applications. When the existing method for modeling the frequency characteristic of winding loss is applied to the toroidal type, the error will be analyzed, and the alternative method for reducing the error is proposed. The AC resistance factor in five inductors with the different number of turns, layers, but the same wire diameter are calculated and compared with that of FEA. The proposed model shows the calculation error within 15% at the frequencies up to 1 MHz in both solid and Litz-wire windings.