Multiple coil flux pad

Abstract

The present invention provides a magnetic flux pad for generating or receiving magnetic flux, comprising at least three coils positioned such that the windings thereof are in substantially the same plane, and a power supply or pickup controller operable to selectively energise or receive power from two or more of the coils such that a magnetic field is produced or received by at least one of a plurality of pairs of the at least three coils. In preferred embodiments, the three or more coils are substantially mutually decoupled, overlapping, and/or equidistantly spaced from one another.

1 . A magnetic flux pad for generating or receiving magnetic flux, the pad comprising:
 at least three coils positioned such that the windings thereof are in substantially the same plane; and   a power supply or pickup controller operable to selectively conduct with two or more of the coils such that a magnetic field is produced or power is received by at least one of a plurality of pairs of the at least three coils.   
     
     
         2 . The magnetic flux pad of  claim 1  wherein the power supply or pickup controller is operable to selectively conduct with the coils to energise or receive power from any one or more of the coils. 
     
     
         3 . The magnetic flux pad of  claim 1 , wherein the power supply or pickup controller is operable to sequentially energise or receive power from the at least three coils. 
     
     
         4 . The magnetic flux pad of  claim 1 , wherein the power supply or pickup controller is operable to independently control the phase, magnitude and/or frequency of current in each of the at least three coils. 
     
     
         5 . The magnetic flux pad of  claim 1 , wherein the at least three coils are substantially mutually decoupled from one another. 
     
     
         6 .- 8 . (canceled) 
     
     
         9 . The magnetic flux pad of  claim 1 , wherein the power supply is operable in a plurality of modes comprising at least two of:
 single-phase modes, wherein one or more of the coils are energised in phase with each other;   two-phase modes, wherein one or more of the coils are simultaneously energised out of phase with one or more other coils; and   a multiphase mode, wherein three or more of the coils are simultaneously energised out of phase with each other.   
     
     
         10 . The magnetic flux pad of  claim 1 , further comprising a magnetically permeable material, wherein the at least three coils are magnetically associated with the permeable material. 
     
     
         11 . The magnetic flux pad of  claim 1 , further comprising a further coil disposed substantially centrally and encircling or partially overlapping the at least three coils. 
     
     
         12 . The magnetic flux pad of  claim 11 , wherein the further coil is substantially mutually decoupled from the at least three coils in at least one mode of operation. 
     
     
         13 . The magnetic flux pad of  claim 1 , comprising:
 three overlapping and substantially mutually decoupled coils each spaced substantially equidistantly from one another, and   a magnetically permeable material providing a low reluctance magnetic path between poles of the three coils.   
     
     
         14 .- 15 . (canceled) 
     
     
         16 . A magnetic flux pad for generating magnetic flux, the magnetic flux pad being configured to be operable in a plurality of modes so as to control the magnetic flux generated thereby, and comprising three or more coils capable of being selectively energised to enable said control to be effected. 
     
     
         17 .- 19 . (canceled) 
     
     
         20 . The magnetic flux pad of  claim 16 , wherein the plurality of modes comprises at least two of:
 single-phase modes, wherein one or more of the coils are energised in phase with each other;   two-phase modes, wherein one or more of the coils are simultaneously energised out of phase with one or more other coils; and   a multiphase mode, wherein three or more of the coils are simultaneously energised out of phase with each other.   
     
     
         21 .- 22 . (canceled) 
     
     
         23 . The magnetic flux pad of  claim 20 , comprising a further substantially central coil. 
     
     
         24 . A power supply apparatus for an inductive power transfer system, the power supply apparatus comprising:
 a magnetic flux pad for generating magnetic flux, comprising at least three coils positioned such that the windings thereof are in substantially the same plane; and   a power supply adapted to provide a current in one coil which has a different phase to a current in the other coils.   
     
     
         25 . The power supply apparatus of  claim 24  wherein the magnetic flux pad further comprises a magnetically permeable material and the at least three coils are magnetically associated with the permeable material. 
     
     
         26 . The power supply apparatus of  claim 24 , wherein the power supply is adapted to provide a current in any one coil so as to have a different phase to a current in all respective other coils in use. 
     
     
         27 . The power supply apparatus of  claim 24 , wherein the power supply is adapted to adjust the phase to produce a field that varies with time and with spatial position on the pad. 
     
     
         28 . The power supply apparatus of  claim 24 , wherein the apparatus comprises means to detect where a field is or is not required in the vicinity of the pad and adjust the phase and/or amplitude of the current in at least one of said coils in response thereto. 
     
     
         29 . The power supply apparatus of  claim 28 , wherein the means to detect is adapted to adjust a relative phase between at least a first of said coils and at least a second of said coils. 
     
     
         30 . The power supply apparatus of  claim 24 , wherein the power supply comprises an inverter for each coil. 
     
     
         31 .- 36 . (canceled)