Sinusoidally-modulated 3MHz-switching GaN stepdown converter for non-resonant 150kHz WPT applications

This paper presents an original approach to the development of a power converter for wireless-power-transfer applications. The idea is based on a buck topology modulated sinusoidally, producing a fundamental sinusoidal waveform at 150kHz and able to exploit conventional inductive coupling solutions, as opposed to resonant coupling. The advantage of this approach is twofold: first, the synthesized voltage can be controlled on the primary side by a simple voltage feedback and kept at nominal value even in the presence of varying load and coupling conditions; second, the efficiency can also be significantly improved as compared with more conventional resonant approaches. As a case-study, a charging system for drone battery is presented, with a nominal power rating of 25W.