Multi‐resonator arrays for smart wireless power distribution: comparison with experimental assessment

Abstract

This study presents the design of efficient wireless power distribution systems based on resonant inductive arrays. The authors show how to use multi‐resonator arrays to charge and power up several electric devices in parallel, with nearly constant transmitted power, and using a single power source. Their single‐source wireless power transmission clusters, for instance, are shown to provide free positioning at better power efficiency than previous solutions. They provide analysis, simulation, and measurement performance of their multi‐resonator arrays, they compare them with other types of inductive arrays employed into different schemes (multi‐coil inductive links, overlapping and non‐overlapping links), and they show the advantage of their strategy over previous solutions. The presented wireless power distribution systems improve power transmission efficiency (PTE) in free positioning by as much as 30%. The measured results show that their multi‐resonator arrays present significant advantages: (i) they allow multiple charging zones from a single power source; (ii) they provide free positioning with strictly uniform power delivered to the load; and (iii) they provide superior efficiency through a built‐in power localization mechanism, which is not available in other solutions. The PTE of the multi‐resonator array in single‐receiver and multi‐receiver configurations outperformed previous solutions by 26% and 12%, respectively.

Wireless Power Transmission with Uniform Power Delivery in the 3D Space of the Human Body using Resonators in Parallel

“…We have characterized the performance of the prototype with (N=4) and without (N=2) the forearm resonators regarding the PTE and PDL. We have calculated PTE by measuring the transmission coefficient, S21, of the link using (2). PTE = S21 2 * 100 % (2) We have used a two-port vector network analyzer (VNA) to measure the S21, where Tx coil, L1, and receiver load coil, L4, are directly connected to the VNA's ports.…”

“…The WPT technology has been used to wirelessly power/charge portable battery-powered devices such as smartphones, industrial and biomedical sensors, electric-vehicles, etc. [2]. The inductive link technology is demonstrated as an excellent approach for sending sub-micro to several tens of milliwatts to implantable devices wirelessly, used for both small animals and humans, to avoid using bulky rechargeable batteries and frequent surgeries to replace them.…”

“…Different configurations of multicoil transmitter arrays are proposed (including the switching approaches, floating resonators designs, parallel resonators designs, etc.) to increase the effective active area where a receiver unit can be located and received sufficient wireless power [2].…”

“…A system with resonators in parallel configuration has the capability of providing uniform PTE and power delivered to the load (PDL) over a large surface or in a large volume by unifying the electromagnetic field and its natural power localization property. This WPT configuration is developed for small animal wireless power cages (for long-term in-vivo experiments with freely moving animals) and smartphone charging platforms [2], [3].…”

Star-Shaped Coils in the Transmitter Array for Receiver Rotation Tolerance in Free-Moving Wireless Power Transfer Applications

“…Power transmission in arrays has also been expanded by using overlapping array structures to increase power transmission and reduce the dark spots where the vector of the modified field is zero. Using interconnected arrays to automatically position the receiver coil and eliminate multiple peaks in the frequency characteristic of adjacent arrays is one of the most important techniques [18].…”