L. Gu, G. Zulauf, A. Stein, P. A. Kyaw, T. Chen and J. M. R. Davila, “6.78-MHz Wireless Power Transfer With Self-Resonant Coils at 95% DC–DC Efficiency,” in IEEE Transactions on Power Electronics, vol. 36, no. 3, pp. 2456-2460, March 2021, doi: 10.1109/TPEL.2020.3014042.
Abstract
Megahertz-frequency inductive wireless power transfer holds the promise of compact and efficient wireless power transfer. Unfortunately, due to high-frequency losses in wide-bandgap semiconductors and low-Q high-frequency coil designs, these systems are universally less efficient, on a dc–dc basis, than wireless power systems operating at conventional frequency regimes. This letter describes the design considerations for inductive wireless power transfer systems operating at 6.78 MHz. With a novel high-frequency resonant amplifier topology, a high-Q self-resonant coil structure, and a better understanding of Coss losses in wide-bandgap power semiconductors, we demonstrate 6.78-MHz wireless power transfer systems that achieve 95% dc–dc efficiency at power levels up to and beyond 1 kW.