A Smart Multicoil Inductively Coupled Array for Wireless Power Transmission

This paper presents a novel resonance-based multicoil array structure to wirelessly charge or power up apparatus, like smart phones, computer mouses, smart animal research systems, or implanted medical devices. The proposed array consists of a novel multicoil inductive link, whose primary resonator is made of several identical coil elements connected in parallel and arranged in an array. Such a structure presents several key features compared to previous inductive coil arrays. The proposed approach can do the following: 1) deliver power with superior efficiency over longer separation distances; 2) naturally track the receiver position and localize transmitted power through nearby coil array elements without the need for complex control and detection circuitry; and 3) accommodate either short- or long-range power transmission applications simply by slightly modifying the receiver topology. The performance of the proposed structure is verified by measurement results. In a three-coil configuration, the prototype provides a power transfer efficiency (PTE) of 83.3% and a power delivered to the load (PDL) of 3.87 W for a separation distance below 1 cm, while in a four-coil configuration, it provides a PTE of 76% and a PDL of 115 mW for a separation distance of 4 cm.