Abstract: This disclosure provides systems, methods and apparatuses for foreign object detection (FOD) in a wireless power transfer (WPT) system. Some implementations relate generally to the use of detection coils that are excited to measure and compare a differential current through a coil pair that includes at least two detection coils. A foreign object may cause a change in impedance for one or more detection coils compared to one or more other detection coils. By detecting the differential current of the coil pair, a detection apparatus may determine that a foreign object is in proximity to one of the detection coils of the coil pair. This disclosure provides several options for the design, construction, layout, and operations of detection coils to improve foreign object detection.

Abstract: This disclosure provides systems, methods and apparatuses for foreign object detection (FOD) in a wireless power transfer (WPT) system. Some implementations relate generally to the use of detection coils that are excited to measure and compare a differential current through a coil pair that includes at least two detection coils. A foreign object may cause a change in impedance for one or more detection coils compared to one or more other detection coils. By detecting the differential current of the coil pair, a detection apparatus may determine that a foreign object is in proximity to one of the detection coils of the coil pair. This disclosure provides several options for the design, construction, layout, and operations of detection coils to improve foreign object detection.

Abstract: One innovative aspect of the subject matter described in this disclosure can be implemented in a wireless power reception apparatus. In some implementations, the wireless power reception apparatus may include a ferrite layer including a void. The wireless power reception apparatus may also include a first secondary coil configured to generate first power in cooperation with one or more primary coils of a wireless power transmission apparatus, where at least a portion of the first secondary coil resides in the void of the ferrite layer. The wireless power reception apparatus may also include one or more second secondary coils configured to generate second power in cooperation with the one or more primary coils of the wireless power transmission apparatus, where a portion of the second secondary coil is overlaying the portion of the first secondary coil residing in the void of the ferrite layer.

Abstract: A method includes utilizing a detection device comprising a detection mat having a plurality of detection coils, and at least one pair of groups of detection coils having a first group of detection coils and a second group of detection coils, and where the first group of detection coils includes a first impedance value, and a second group of detection coils includes a second impedance value. The method further includes determining alignment parameters representative of electromagnetic coupling between at least one pair of groups of detection coils of the detection mat and an electromagnetic field generated by an apparatus coil, and comparing the alignment parameters with a reference. The method also includes generating a control signal indicative of an alignment position of the apparatus coil with respect to the detection mat based on the compared alignment parameters.

Abstract: A wireless charging device is disclosed. The wireless charging device includes a transmitter detection coil configured to receive a first alternating current (AC) voltage signal having a characteristic associated with a receiver device. Also, the wireless charging device includes a control unit coupled to the transmitter detection coil and configured to detect the receiver device based on the characteristic of the first AC voltage signal. Further, the wireless charging device includes a driver unit coupled to the control unit and configured to convert a direct current (DC) voltage signal of an input power to a second AC voltage signal if the receiver device is detected. In addition, the wireless charging device includes a power transmission coil configured to wirelessly transmit the second AC voltage signal to the receiver device.