Power Delivery and Leakage Field Control Using an Adaptive Phased Array Wireless Power System

Efficient wireless power transfer and precise control of power delivery and leakage field strength can be achieved using a phased array wireless power transfer system. This has particular importance for charging multiple devices simultaneously, or charging devices in environments where humans or foreign objects will be in close proximity. The phased array wireless power system consists of two or more phase-synchronized power amplifiers each driving a respective transmit coil. The system can maximize power delivery to an intended receiver in one location while simultaneously minimizing power delivery and leakage fields in other locations. These functions are possible by varying the amplitude and phase of each transmitter. This paper provides an analysis of a phased array wireless power transfer system using near-field magnetically coupled resonators, and derives parameters that can be used to automatically determine the optimal magnitude and phase of each transmitter to deliver power to one or more receivers. Experimental results verify the theoretical analysis and additional features of the full system are demonstrated.