Capacitive Receiver Detection in Wireless Power Transmitters

The patent replaces the inductive detection method (energizing transmitter coils to detect receivers) with a capacitive detection method. Instead of using electromagnetic induction, the system uses a capacitive sensor that measures changes in capacitance caused by the proximity of a receiver device. This substitution eliminates the need to energize transmitter coils for detection purposes, thereby resolving the contradiction between detection capability and power consumption.

The patent substitutes the electromagnetic inductive detection system with a capacitive sensing system. The capacitive sensor detects receiver presence through changes in electrical field capacitance rather than through electromagnetic induction. This replacement eliminates the generation of strong alternating magnetic fields that cause electromagnetic interference, while maintaining the ability to detect receiver presence through capacitance changes.

The patent makes the capacitive sensor serve multiple functions: it detects receiver presence and can potentially determine receiver position, all without requiring energization of transmitter coils. The capacitive sensing network covers the entire transmitter surface area, providing comprehensive detection coverage while consuming minimal power, thus resolving the contradiction between coverage area and power consumption.