Analytical Methods for Determining High Frequency Winding Loss for Toroidal Inductors

Inductors are energy storage devices that serve as key components in power conversion technology. The advent of wide-bandgap (WBG) semiconductor devices has led to high frequency operation of power converters at higher voltage and current levels. In the range of 20kHz-1MHz, additional sources of loss in magnetic components interfacing to these WBG semiconductors are introduced due to high-frequency electromagnetic phenomena. Finite element analysis can capture these effects to a high degree of accuracy but require extensive computation time precluding their application in robust optimization and design schemes. There exist several analytical models for winding loss in literature that can evaluate multiple designs with minimal computation cost. In this work, popular models are reviewed, investigated, and expanded on in the context of various toroidal winding geometries. The goal of this work is to analyze well-known winding loss models and demonstrate their accuracies at high frequency (beyond 20kHz) as they pertain to toroidal inductors while maintaining the low computation cost required for integration into optimization and design schemes.