A Robust Simultaneous Wireless Power and Information Transfer System for Charging Battery With Wide Charging Region

This article proposes a robust simultaneous wireless power and information transfer (SWPIT) system with constant current (CC) or constant voltage (CV) output. This system achieves stable output and high-misalignment-tolerant wireless charging under variable transfer distance and load, even when the system is detuned. First, the frequency and output characteristics are analyzed based on the autonomous circuit principle and coupled mode theory. A method of phase synchronization and eigenfrequency tracking is presented to reduce the fluctuation of output. Second, benefiting from the frequency characteristics of this autonomous system, a low-delay wireless information transfer based on the parity-time (PT) symmetry is realized. Moreover, a closed-loop control strategy is designed for CC or CV output. Finally, an experimental prototype is established. The experimental results show that the maximum change rate of output is 2.6% in the CC mode and 1.2% in the CV mode, within 40% misalignment distance of the largest size in the
$Y$
-direction and 10.5% detuning rate.