Wireless power transfer for appliances and equipments

Abstract

Exemplary embodiments are directed to wireless power transfer. A transmitting device or a receiving device for use in a wireless transfer system may be equipment or a household appliance. The transmitting device includes a transmit antenna to wirelessly transfer power to a receive antenna by generating a near field radiation within a coupling-mode region. An amplifier applies an RF signal to the transmit antenna. A presence detector detects a presence of a receiver device within the coupling-mode region. A controller adjusts a power output of the amplifier responsive to the presence of a receiver device. The presence detector may also detect a human presence. The power output may be adjusted at or below the regulatory level when the presence signal indicates human presence and above a regulatory level when the presence signal indicates human absence.

What is claimed is: 
     
         1 . An apparatus for wirelessly transferring power to a receive antenna of a receiver device, comprising:
 a transmit antenna configured to generate an electromagnetic field to wirelessly transfer the power to the receive antenna within a coverage area of the transmit antenna;   an amplifier configured to output electric power to the transmit antenna for generating the electromagnetic field;   a presence detector configured to detect a presence of the receiver device within the coverage area and configured to generate a presence signal in response to the detection of the presence of the receiver device; and   a controller operably coupled to the presence detector and configured to reduce a power output of at least one of the transmit antenna and the amplifier following a time delay after the presence signal indicates the absence of any receiver devices in the coverage area.   
     
     
         2 . The apparatus of  claim 1 , wherein:
 the presence detector is further configured to detect a human presence and to modify the presence signal to indicate the human presence or the human absence; and   the controller is further configured to:   adjust the power output of the amplifier to a high power level above a regulatory level when the presence signal indicates the human absence; and   adjust the power output of the amplifier to at or below the regulatory level when the presence signal indicates the human presence.   
     
     
         3 . The apparatus of  claim 1 , wherein the presence detector is selected from the group consisting of a motion detector, an infrared detector, and a combination thereof. 
     
     
         4 . The apparatus of  claim 1 , wherein the controller is further configured to remove power from at least one of the transmit antenna and the amplifier after the time delay. 
     
     
         5 . The apparatus of  claim 1 , wherein the time delay is longer than a time needed for the apparatus to substantially fully charge a specific type of wireless device. 
     
     
         6 . The apparatus of  claim 1 , wherein the time delay is adjustable by a user. 
     
     
         7 . The apparatus of  claim 1 , wherein the apparatus comprises a computer and the transmit antenna is disposed on or in a back surface of a display of the computer. 
     
     
         8 . The apparatus of  claim 7 , wherein the transmit antenna comprises a multi-turn loop. 
     
     
         9 . The apparatus of  claim 1 , wherein the apparatus comprises a computer and the transmit antenna is disposed in a periphery around a display of the computer. 
     
     
         10 . The apparatus of  claim 1 , wherein the transmit antenna is further configured to generate the electromagnetic field at a resonant frequency of the transmit antenna. 
     
     
         11 . A method, comprising:
 generating, at a transmit antenna, an electromagnetic field to wirelessly transfer power from the transmit antenna to a receive antenna of a receiver device in a coverage area of the transmit antenna;   outputting, at an amplifier, electric power to the transmit antenna for generating the electromagnetic field;   detecting a presence of the receiver device within the coverage area and generating a presence signal in response to the detection of the presence of the receiver device; and   reducing a power output of at least one of the transmit antenna and the amplifier following a time delay after the presence signal indicates the absence of any receiver devices in the coverage area.   
     
     
         12 . The method of  claim 11 , wherein the reducing comprises removing power from at least one of the transmit antenna and the amplifier after the time delay. 
     
     
         13 . The method of  claim 11 , wherein the time delay is longer than a time needed for the apparatus to substantially fully charge a specific type of wireless device. 
     
     
         14 . The method of  claim 11 , wherein the time delay is adjustable by a user. 
     
     
         15 . The method of  claim 11 , wherein the electromagnetic field is generated at a resonant frequency of the transmit antenna. 
     
     
         16 . A wireless power transfer system, comprising:
 means for generating an electromagnetic field to wirelessly transfer power to a receive antenna of a receiver device in a coverage area of the generating means;   means for outputting electric power to the transmit antenna for generating the electromagnetic field;   means for detecting a presence of the receiver device within the coverage area and generating a presence signal in response to the detection of the presence of the receiver device; and   means for reducing a power output of at least one of the generating means and the outputting means following a time delay after the presence signal indicates the absence of any receiver devices in the coverage area.   
     
     
         17 . The system of  claim 16 , wherein the reducing means comprises means for removing power from at least one of the generating means and the outputting means after the time delay. 
     
     
         18 . The system of  claim 16 , wherein the generating means comprises a transmit antenna configured to generate the electromagnetic field at a resonant frequency of the transmit antenna. 
     
     
         19 . The system of  claim 16 , wherein the outputting means comprises an amplifier, wherein the detecting means comprises a presence detector, and wherein the reducing means comprises a controller. 
     
     
         20 . The system of  claim 16 , wherein the time delay is longer than a time needed for the system to substantially fully charge a specific type of wireless device.