Wireless electric field power transfer system, method, transmitter and receiver therefor

Abstract

A wireless electric field power transmission system comprises: a transmitter comprising a transmitter antenna, the transmitter antenna comprising at least two conductors defining a volume therebetween; and at least one receiver, wherein the transmitter antenna transfers power wirelessly via electric field coupling when the at least one receiver is within the volume.

1 . (canceled) 
     
     
         2 . A transmitter for wirelessly transmitting power, the transmitter comprising:
 an antenna for creating an electric field, the antenna comprising at least one conductor;   a coil connected to the antenna; and   a resonator connected to the coil for resonating the coil and the conductor at a resonant frequency, the resonator comprising a tuning circuit having a sensor configured to sense an output at the antenna, wherein the antenna receives a feedback signal based on the sensed output.   
     
     
         3 . The transmitter of  claim 2 , wherein the tuning circuit further comprises:
 an oscillator configured to inject a start-up signal into the tuning circuit via a switch.   
     
     
         4 . The transmitter of  claim 3 , wherein the tuning circuit further comprises:
 an envelope detector connected to the sensor and the switch.   
     
     
         5 . The transmitter of  claim 4 , wherein the switch is conditioned to disconnect the tuning circuit from the oscillator after receiving a signal from the envelope detector. 
     
     
         6 . The transmitter of  claim 2 , wherein the tuning circuit further comprises:
 a switch conditioned to isolate the antenna if the sensed output exceeds a pre-determined safety tolerance.   
     
     
         7 . The transmitter of  claim 6 , wherein the switch is conditioned to isolate the transmitter from input power if the sensed output exceeds the pre-determined safety tolerance. 
     
     
         8 . The transmitter of  claim 2 , wherein the tuning circuit further comprises:
 a delay line configured to delay a power signal to the antenna.   
     
     
         9 . The transmitter of  claim 2 , wherein the tuning circuit further comprises:
 a balun configured to decouple the coil from ground.   
     
     
         10 . The transmitter of  claim 2 , wherein the output is any one of an output voltage and current at the antenna, an output current at the antenna and a phase of an output current at the antenna. 
     
     
         11 . The transmitter of  claim 2 , wherein the sensor is a current-sensing toroid. 
     
     
         12 . A method of tuning a transmitter for wirelessly transmitting power, the method comprising:
 providing an antenna for creating an electric field, the antenna connected to a coil, wherein the antenna comprises at least one conductor;   resonating the conductor and the coil at a start-up frequency; and   sensing an output at the antenna.   
     
     
         13 . The method of  claim 12 , further comprising:
 receiving a signal at a switch connected to the antenna, the signal based on the sensed output.   
     
     
         14 . The method of  claim 13 , further comprising:
 disconnecting the antenna from a source of the start-up frequency via the switch after the switch receives the signal.   
     
     
         15 . The method of  claim 13 , further comprising:
 disconnecting the antenna from a power source to the antenna via the switch after the switch receive the signal.   
     
     
         16 . The method of  claim 12 , further comprising:
 processing the sensed output.   
     
     
         17 . The method of  claim 16 , further comprising:
 inputting the processed output to the antenna   
     
     
         18 . The method of  claim 17 , further comprising:
 delaying the processed output prior to the inputting.   
     
     
         19 . The method of  claim 18 , wherein the delaying is performed via a delay line comprising inverters. 
     
     
         20 . The method of  claim 13 , further comprising:
 detecting an envelope of the sensed output.   
     
     
         21 . The method of  claim 20 , wherein the detecting is performed via an envelope detector. 
     
     
         22 . The method of  claim 20 , further comprising:
 outputting the envelope to the switch.   
     
     
         23 . A wireless electric field power transmission system for powering a load, the system comprising:
 a transmitter for wirelessly transmitting power, the transmitter comprising:
 a transmitter antenna for creating an electric field, the transmitter antenna comprising at least one conductor; 
 a transmitter coil connected to the transmitter antenna; and 
 a resonator connected to the transmitter coil for resonating the transmitter coil and the conductor of the transmitter antenna at a resonant frequency, the resonator comprising a tuning circuit having a sensor configured to sense an output at the transmitter antenna, wherein the antenna receives a feedback signal based on the sensed output; and 
   a receiver for receiving wirelessly transmitted power from the transmitter, the receiver comprising:
 a receiver antenna comprising at least two conductor, the receiver antenna configured to receive power from the transmitter antenna via resonant electric field coupling; 
 a receiver coil connected to the receiver antenna; and 
 a power harvester connected to the receiver coil, the power harvester configured to extract power received by the receiver antenna.