Three-coil topology for wireless power transfer

Abstract

A system using a three-coil topology for wireless power transfer is disclosed. The system comprises a primary resonator coupled to a power source, a repeater resonator and a receiver resonator. The primary resonator has a primary coil, and the repeater resonator has a repeater coil adjacent to the primary coil. The repeater coil and the primary coil are separated by a distance selected, and the repeater coil is configured, to amplify a primary-coil current by inductively generating a repeater-coil current that is substantially greater than the primary-coil current. A magnetic field contributed from both the primary-coil current and the repeater-coil current is generated while the power source needs not provide a terminal voltage across the repeater coil, thereby discouraging occurrence of voltage stress at the power source. The receiver resonator has a receiver coil, which receives the magnetic field to inductively generate a receiver-coil current for feeding to a load.