Method and device for detecting a device in a wireless power transmission system

A transmitter (800) for detecting a receiver (106, 214, 2311, 2521), the transmitter (800) being intended to transmit power inductively to the receiver (106, 214, 2311, 2521), the transmitter (800) comprising:

• a first transmission coil (218, 704, 810, 1504) as a first electrode (204, 704, 810, 904, 1504) and a second electrode (206, 702, 812, 906, 1506), the first electrode (204, 704, 810, 904, 1504) and the second electrode (206, 702, 812, 906, 1506) forming a capacitor (202, 802),
• a first unit (216) for applying a voltage to any one of electrodes (204, 206, 702, 704, 810, 812, 904, 906, 1504, 1506),
• detection circuitry (212) connected to any one of the electrodes (204, 206, 702, 704, 810, 812, 904, 906, 1504, 1506) of the capacitor (202, 802) for detecting a capacitance change of the capacitor (202, 802).

A method (2600) of detecting a receiver by a transmitter (800), wherein the transmitter (800) is intended to transmit power inductively to the receiver (106, 214, 2311, 2521), the transmitter (800) comprising a first transmission coil (218, 704, 810, 1504) as an electrode (220), the method comprising:

• applying (2602) a voltage to the electrode (220),
• detecting (2604) a capacitance change of a capacitor formed by the electrode (220) and a ground (222) or formed by the electrode (220) and the receiver.

A transmitter (800) for detecting a receiver (106, 214, 2311, 2521), the transmitter (800) being intended to transmit power inductively to the receiver (106, 214, 2311, 2521), the transmitter (800) comprising:

• a first transmission coil as a first electrode (220),
• a first unit (216) for applying a voltage to the electrode (220),
• detection circuitry (212) connected to the electrode (220) for detecting a capacitance change of a capacitor formed by the electrode (220) and a ground (222) or formed by the electrode (220) and the receiver.