Novel Control Circuit of Resonant Frequency Adjusting Circuit for Extending Reactance Compensation Range of Repeater Resonator for Inductive Coupling Wireless Power Transfer

Abstract

Wireless power supply systems using repeater resonators are expected to be a promising technology for supplying power to small-powered IoT devices distributed over a wide area. However, the detuning of the repeater resonator caused by the manufacturing tolerance as well as magnetic interference with the transmitter can reduce the amplitude of the repeater current, which leads to the reduction in the power transfer. To address this problem, an autonomous resonant frequency adjusting circuit was proposed for the repeater resonator. However, this method suffers from limited tuning capability because the adjustable range of the autonomous resonant frequency adjustment circuit is limited under high frequency operating conditions. This paper proposes an improved circuit based on this preceding autonomous resonant frequency adjustment circuit to expand the adjustable range in high-frequency operation.