Advantages and Characteristics of a WPT System with a Resonant Wired-2-Coil Repeater

A near-field wireless power transfer (WPT) with magnetic resonant coupling (MRC) offers a dynamic means for charging various electric apparatuses. This paper presents the modeling and characteristics of a system with a resonant wired-2-coil repeater that can charge devices in any available space using a repeater wire. Moreover, resonant frequencies are discussed, and a method to tune the frequencies is described. Experimental results show that the modeling and tuning methods are valid and that the system can maintain a power transfer efficiency of more than 80% even when the repeater wire is 10-m long.