Inductive power transfer apparatus

Abstract

An IPT system magnetic flux pad includes two substantially planar coils ( 17 ) in close proximity to each other above a magnetically permeable core ( 14 ). The coils ( 17 ) each define a pole area ( 11, 12 ) and the distance between one or more adjacent turns of the coils ( 17 ) located in a region between the pole areas ( 11, 12 ) being different from the distance between one or more adjacent turns of the coils ( 17 ) located outside the region between the pole areas ( 11, 12 ).

1 . An IPT system magnetic flux pad for generating or receiving a. magnetic flux, the pad comprising:
 two substantially planar coils in close proximity to each other and being magnetically associated with a magnetically permeable core, the coils each defining a pole area and a distance between one or more adjacent turns of the coils located in a region between the pole areas being different from a distance between one or more adjacent turns of the coils located outside the region between the pole areas.   
     
     
         2 . An WI system magnetic flux pad as claimed in  claim 1  wherein the distance between one or more adjacent turns of the coils located in a region between the pole areas is less than the distance between one or more adjacent turns of the coils located outside the region between the pole areas. 
     
     
         3 . An IPT system magnetic flux pad as claimed in  claim 1  wherein the distance between one or more adjacent turns of the coils located in a region between the pole areas is greater than the distance between one or more adjacent turns of the coils located outside the region between the pole areas. 
     
     
         4 . An IPT system magnetic flux pad as claimed in  claim 1  whereby one or more turns of the coils located in a region between the pole areas are more closely magnetically associated with the magnetically permeable core than one or more turns of the coils located outside the region between the pole areas. 
     
     
         5 . An IPT system magnetic flux pad for generating or receiving a magnetic flux, the pad comprising:
 two substantially planar coils in close proximity to each other, the coils each defining a pole area, a magnetically permeable core extending in a longitudinal direction between the pole areas, and wherein the magnetically permeable core is discontinuous in the transverse direction.   
     
     
         6 . An IPT system magnetic flux pad as claimed in  claim 5  wherein each pole area comprises a centre center of a respective coil. 
     
     
         7 . (canceled) 
     
     
         8 . (canceled) 
     
     
         9 . An IPT system magnetic flux pad as claimed in  claim 5  wherein the coils comprise copper clad aluminium litz wire. 
     
     
         10 . An IPT system magnetic flux pad as claimed in  claim 5  wherein the core comprises a plurality of spaced bars or strips of a magnetically permeable material. 
     
     
         11 - 23 . (canceled) 
     
     
         24 . An IPT system magnetic flux receiver pad comprising:
 two substantially planar coils in close proximity to each other and being magnetically associated with a magnetically permeable core; and   a further substantially planar coil overlapping the other two coils, and the coils being. wound such that an impedance is reflected onto a flux transmission structure which compensates for a change in an inductance of the transmission structure due to a presence of the receiver pad.   
     
     
         25 . (canceled) 
     
     
         26 . An IPT system magnetic flux receiver pad as claimed in  claim 24  wherein the two coils are connected in series. 
     
     
         27 . An IPT system magnetic flux receiver pad as claimed in  claim 24  wherein the further coil is in spatial quadrature to the other two coils. 
     
     
         28 . An IPT system magnetic flux receiver pad as claimed in  claim 24  wherein the coils comprise aluminium litz wire. 
     
     
         29 - 36 . (canceled) 
     
     
         37 . An IPT system magnetic flux pad as claimed in  claim 1  wherein each pole area comprises a center of a respective coil. 
     
     
         38 . An IPT system magnetic flux pad as claimed in  claim 1  wherein the coils comprise copper clad aluminium litz wire. 
     
     
         39 . An IPT system magnetic flux pad as claimed in  claim 1  wherein the core comprises a plurality of spaced bars or strips of a magnetically permeable material. 
     
     
         40 . An IPT system magnetic flux receiver pad as claimed in  claim 24  the coils defining a pole area, wherein each pole area comprises a center of a. respective coil of the two coils. 
     
     
         41 . An IPT system magnetic flux receiver pad as claimed in  claim 24  wherein the coils comprise copper clad aluminium litz wire. 
     
     
         42 . An IPT system magnetic flux receiver pad as claimed in  claim 24  wherein the core comprises a plurality of spaced bars or strips of a magnetically permeable material. 
     
     
         43 . An IPT system magnetic flux receiver pad as claimed in  claim 24  wherein the coils. are spiral wound coils. 
     
     
         44 . An IPT system magnetic flux receiver pad as claimed in  claim 24  wherein the two coils are co-planar.