Wireless Power Transfer (WPT) systems for charging consumer devices

Abstract Wireless power transfer (WPT) is an emerging technology with an increasing number of potential applications totransfer power from a transmitter to a mobile receiver over a relatively large air gap. However, its widespread application is hampereddue to the relatively low efficiency of currentWireless power transfer (WPT) systems. This study presents a concept to maximizethe efficiency as well as to increase the amount of extractable power of a WPT system operating in non resonant operation. Theproposed method is based on actively modifying the equivalent secondary-side load impedance by controlling the phase-shift ofthe active rectifier and its output voltage level. The presented hardware prototype represents a complete wireless charging system,including a dc–dc converter which is used to charge a battery at the output of the system. Experimental results are shown for theproposed concept in comparison to a conventional synchronous rectification approach. The presented optimization method clearlyoutperforms state-of-the-art solutions in terms of efficiency and extractable power.