This publication describes a motorized wireless power transfer (WPT) system (e.g., motorized Qi charger) that utilizes tunnel magnetoresistance (TMR) to automatically laterally and vertically align the transmitter (Tx) of the WPT system to the receiver (Rx) of a user equipment (UE), such as a smartphone, earphones, a smartwatch, and so forth. The WPT system has TMR sensors that utilize magnetic tunnel junction (MTJ) elements that exhibit low magnetic hysteresis and high magnetoresistance sensitivity to a change in the magnetic field. An array of TMR sensors can be used to reliably detect the magnetic field distribution and can detect the lateral, vertical alignment, and/or misalignment between the Tx of the WPT system and the Rx of the UE. The exact number and spatial arrangements of the TMR sensors may differ depending on the shape and size of the charging pad of the WPT system. The WPT system may have one, two, three, and so forth, transmitters sitting on top of one, two, three, and so forth, motorized arms that enable the WPT system to automatically laterally and/or vertically align to and charge one, two, three, and so forth, UE at the same time. The described WPT system can support different-size UE, can wirelessly charge multiple UE at the same time, increases the coupling coefficient, increases the transferred-power efficiency, decreases power loss, decreases charging time, may mitigate damages to the UE and the WPT system caused by thermal energy, enhances user experience, and enables a user to use electric energy more efficiently.
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Yang, Haoxiang; Yang, Liyu; Jia, Liang; and Shone, Rob, "Motorized Wireless-Charging Pad that Uses Magnetic Field Detection", Technical Disclosure Commons, (August 12, 2019)