Transmission-guard system and method for an inductive power supply

Abstract

An inductive power outlet operable to transfer power to an inductive power receiver includes a driver wired to a primary inductive coil and operable to provide a driving voltage across the primary inductive coil. The primary inductive coil is configured to form an inductive couple having a characteristic resonant frequency with at least one secondary inductive coil wired to an electric load, the secondary inductive coil being associated with the inductive power receiver. The driving voltage oscillates at a transmission frequency substantially different from the characteristic resonant frequency of the inductive couple.

What is claimed is: 
     
         1 . An inductive power outlet operable to transfer power to an inductive power receiver, the inductive power outlet comprising:
 a driver wired to a primary inductive coil and operable to provide a driving voltage across the primary inductive coil;   wherein:
 the primary inductive coil is configured to form an inductive couple having a characteristic resonant frequency with at least one secondary inductive coil wired to an electric load, the secondary inductive coil associated with the inductive power receiver; and 
 the driving voltage oscillates at a transmission frequency substantially different from the characteristic resonant frequency of the inductive couple. 
   
     
     
         2 . The inductive power outlet of  claim 1  wherein the driver comprises a switching unit for intermittently connecting the primary inductive coil to a power supply. 
     
     
         3 . The inductive power outlet of  claim 1  wherein the transmission frequency lies within a range in which induced voltage varies approximately linearly with frequency. 
     
     
         4 . The inductive power outlet of  claim 1  the inductive power outlet comprising a signal detector adapted to detect a first signal and a second signal, and the driver is configured to:
 increase the transmission frequency when the first signal is detected by the detector, and 
 decrease the transmission frequency when the second signal is detected by the detector. 
 
     
     
         5 . The inductive power outlet of  claim 1  the driver being configured to adjust power in response to feedback signals. 
     
     
         6 . The inductive power outlet of  claim 5  wherein the feedback signals carry data pertaining to operational parameters of the electric load. 
     
     
         7 . The inductive power outlet of  claim 6  wherein the operational parameters are selected from the group consisting of:
 required operating voltage for the electric load; 
 required operating current for the electric load; 
 required operating temperature for the electric load; 
 required operating power for the electric load; 
 measured operating voltage for the electric load; 
 measured operating current for the electric load; 
 measured operating temperature for the electric load; 
 measured operating power for the electric load; 
 power delivered to the primary inductive coil; 
 power received by the secondary inductive coil; and 
 a user identification code. 
 
     
     
         8 . The inductive power outlet of  claim 1  wherein the driver further comprises a voltage monitor for monitoring the amplitude of a primary voltage across the primary coil. 
     
     
         9 . The inductive power outlet of  claim 8  wherein the voltage monitor is configured to detect significant increases in primary voltage. 
     
     
         10 . The inductive power outlet of  claim 1  the driver being configured to adjust transmission frequency in response to feedback signals. 
     
     
         11 . The inductive power outlet of  claim 1  the driver being configured to adjust duty cycle of the driving voltage in response to feedback signals. 
     
     
         12 . The inductive power outlet of  claim 1  the driver being configured to adjust amplitude of the driving voltage in response to feedback signals. 
     
     
         13 . The inductive power outlet of  claim 1  further comprising a signal receiving circuit comprising a demodulator operable to demodulate a modulated signal from the inductive power receiver and to produce an output signal. 
     
     
         14 . An inductive power receiver comprising at least one secondary inductive coil wired to an electric load, the secondary inductive coil for forming an inductive couple having a characteristic resonant frequency with at least one primary inductive coil associated with an inductive power outlet comprising at least one driver configured to provide a driving voltage across the primary inductive coil, the driving voltage oscillating at a non-resonant transmission frequency substantially different from the characteristic resonant frequency of the inductive couple,
 wherein the inductive power receiver further comprises:   a power monitor for monitoring power received by the electric load; and   a signal transmitter for communicating feedback signals to the inductive power outlet.   
     
     
         15 . The inductive power receiver of  claim 14 , wherein the signal transmitter comprises a transmission circuit wired to the secondary inductive coil, the transmission circuit for connecting at least one electric element to the secondary inductive coil thereby changing the resonant frequency such that change in transmission voltage may be detected by the inductive power outlet. 
     
     
         16 . The inductive power receiver of  claim 15  wherein the transmission circuit further comprises a modulator for modulating a bit-rate signal with an input signal to create a modulated signal and a switch for intermittently connecting the electrical element to the secondary inductive coil according to the modulated signal. 
     
     
         17 . The inductive power receiver of  claim 14 , the signal transmitter being configured to send feedback signals carry data pertaining to operational parameters of the electric load. 
     
     
         18 . The inductive power receiver of  claim 17  wherein the operational parameters are selected from the group consisting of:
 required operating voltage for the electric load; 
 required operating current for the electric load; 
 required operating temperature for the electric load; 
 required operating power for the electric load; 
 measured operating voltage for the electric load; 
 measured operating current for the electric load; 
 measured operating temperature for the electric load; 
 measured operating power for the electric load; 
 power delivered to the primary inductive coil; 
 power received by the secondary inductive coil; and 
 a user identification code. 
 
     
     
         19 . A method for transferring power from an inductive power outlet to an inductive power receiver, the method comprising:
 forming an inductive couple between at least one primary inductive coil and a secondary inductive coil of the inductive power receiver, the inductive couple having a characteristic resonant frequency; and   providing an oscillating driving voltage across the primary inductive coil such that a secondary voltage is induced in the secondary inductive coil, wherein the oscillating driving voltage has a transmission frequency substantially different from the characteristic resonant frequency of the inductive couple.   
     
     
         20 . The method of  claim 19  further comprising:
 modulating a bit-rate signal with an input signal to create a modulated signal; and 
 connecting the secondary inductive coil to an electric element to alter a characteristic resonant frequency of the inductive couple according to the modulated signal, the inductive power outlet cross-correlating amplitude of the driving voltage with the bit-rate signal to produce a feedback signal.