3-D wireless charging system with flexible receiver coil alignment

Abstract

A 3-D wireless charging system with spatial freedom of positioning is proposed in this paper. By independently adjusting the phase and the amplitude of the input signals, the blind spots within a cylindrical volume are eliminated. Moreover, the symmetric arrangement of the transmitting coils yields a uniform magnetic field around longitudinal axis. Experiments were conducted on a wearable device and a cell phone at 6.78 MHz. The system including a power amplifier and rectifiers achieved an overall power transfer efficiency of 39% for supporting two devices simultaneously.