Arbitrary Magnetic Field Control Technique by Multi-Coil Transmitter Voltage Phase Shifting for Omni-Directional Free-Positioning Magnetic Resonance Wireless Power Delivery

This paper presents a technique to efficiently transfer power to devices regardless of their angle and position by using multi-coil transmitter with magnetic resonance coupling. The magnetic field at receiver coil can be arbitrary controlled by changing the phase of transmitter switching signal. The optimum phase can be determined by reversely transmitting signal from receiver to transmitter and detecting the phase of induced voltage of each transmitter coil. The effectiveness of proposed technique is demonstrated by electro-magnetic field simulation and measurements.