Inductively coupled power transfer systems

Abstract

In an inductively coupled power transmitter a force detector that detects the presence of a potential device by monitoring forces applied to a surface of the power transmitter and activates the inductively coupled power transmitter upon detection of a potential device. An inductively coupled power transmitter having a proximity detector that detects the presence and location of a potential device by monitoring the proximity of devices to a surface of the power transmitter and activates the inductively coupled power transmitter upon detection of a potential device. The transmitter preferably has one or more detection coils each having an area much greater than that of the transmitter coils for detecting the presence of a potential device. An inductively coupled power transmitter including a plurality of transmitter coils proximate a charging surface and a controller selecting and driving a combination of transmitter coils providing the coupling between the power transmitter and a power receiver meeting a selection criteria.

1 . A wireless power transmitter comprising:
 at least one wireless power transmitter coil;   a detector configured to detect a presence of a wireless power receiver proximate the wireless power transmitter and activate the wireless power transmitter responsive to the presence of the wireless power receiver.   
     
     
         2 . The wireless power transmitter of  claim 1  wherein the detector is configured to detect the presence of a potential wireless power receiving device by detecting a force associated with the potential wireless power receiving device being placed proximate the wireless power transmitter. 
     
     
         3 . The wireless power receiver of  claim 1  further comprising a controller configured to perform further detection in response to an activation signal from the detector. 
     
     
         4 . The wireless power receiver of  claim 3  wherein the further detection includes determining a transmitter configuration suitable to power the potential wireless power receiving device. 
     
     
         5 . The wireless power transmitter of  claim 1  wherein the detector is further configured to detect a location of the potential wireless power receiver relative to the wireless power transmitter. 
     
     
         6 . The wireless power transmitter of  claim 1  wherein the detector is selected from the group consisting of: a load cell, an accelerometer, a detection coil, a capacitive touch sensor, a resistive touch sensor. 
     
     
         7 . The wireless power transmitter of  claim 1  further comprising a controller configured to respond to a signal from the detector indicating the presence of a wireless power receiver by activating the wireless power transmitter, wherein the controller is further configured to determine an optimum power output level for the transmitter. 
     
     
         8 . The wireless power transmitter of  claim 7  wherein the controller is configured to determine an optimum power output level for the transmitter by increasing magnetic field strength of the at least one wireless power transmitter coil until the wireless power receiver stops accepting more power. 
     
     
         9 . The wireless power transmitter of  claim 7  wherein the controller is configured to determine an optimum power output level for the transmitter by decreasing magnetic field strength of the at least one wireless power transmitter coil until a wireless power level drops. 
     
     
         10 . The wireless power transmitter of  claim 7  wherein the controller is configured to determine an optimum power output level for the transmitter by decreasing magnetic field strength of the at least one wireless power transmitter coil until a maximum efficiency point is reached. 
     
     
         11 . A wireless power transmitter comprising:
 at least one wireless power transmitter coil;   a detector configured to detect a presence of a wireless power receiver proximate the wireless power transmitter; and   a controller configured to respond to a signal from the detector indicating the presence of a wireless power receiver by activating the wireless power transmitter, wherein the controller is further configured to determine an optimum power output level for the transmitter.   
     
     
         12 . The wireless power transmitter of  claim 11  wherein the controller is configured to determine an optimum power output level for the transmitter by increasing magnetic field strength of the at least one wireless power transmitter coil until the wireless power receiver stops accepting more power. 
     
     
         13 . The wireless power transmitter of  claim 11  wherein the controller is configured to determine an optimum power output level for the transmitter by decreasing magnetic field strength of the at least one wireless power transmitter coil until a wireless power level drops. 
     
     
         14 . The wireless power transmitter of  claim 11  wherein the controller is configured to determine an optimum power output level for the transmitter by decreasing magnetic field strength of the at least one wireless power transmitter coil until a maximum efficiency point is reached. 
     
     
         15 . A method of operating a wireless transmitter, the method comprising using a detector of the wireless transmitter to detect a presence of a wireless power receiver proximate the wireless power transmitter and activate the wireless power transmitter responsive to the presence of the wireless power receiver. 
     
     
         16 . The method of  claim 15  wherein the detector detects the presence of a wireless power receiver by detecting a force associated with the wireless power receiver device being placed proximate the wireless power transmitter. 
     
     
         17 . The method of  claim 15  further comprising using a controller of the wireless transmitter to perform further detection in response to an activation signal from the detector. 
     
     
         18 . The method of  claim 17  wherein the further detection includes using a controller of the wireless power transmitter to determine a transmitter configuration suitable to power the wireless power receiver. 
     
     
         19 . The method of  claim 18  wherein the transmitter configuration suitable to power the wireless power receiver includes an optimum power output level for the transmitter. 
     
     
         20 . The method of  claim 19  wherein the controller determines the optimum power output level for the transmitter by at least one of:
 increasing magnetic field strength of the at least one wireless power transmitter coil until the wireless power receiver stops accepting more power; 
 decreasing magnetic field strength of the at least one wireless power transmitter coil until a wireless power level drops; or 
 decreasing magnetic field strength of the at least one wireless power transmitter coil until a maximum efficiency point is reached.