A High Frequency Coupled Inductor Design for High Power Density DC-DC Converters

Coupled inductors has been extensively adopted in DC-DC converters due to their distinctive features, such as the flux cancelation ability, enhanced performance, higher power density and lower weight compared to their non-coupled counterparts. The fast-switching speed of the wide bandgap power electronics demands high frequency, high density, and more efficient passive components, especially the inductors. In this paper, we present a high frequency coupled inductor design using parallel air gaps and copper foil windings with the commercial off-the-shelf planar magnetic cores. The proposed inductor is prototyped and demonstrated in a four-phase interleaved, 50 kW boost converter. The developed inductor prototype has a volume less than 0.5 L and a resonant frequency over 7 MHz with much lower ac resistance compared to a printed circuit board (PCB) based inductor.