Inductive power transfer apparatus
View Patent ↗A magnetic flux pad for receiving or generating magnetic flux. The pad includes two pole areas ( 11, 12 ) associated with a magnetically permeable core 14 . Coils 17 define the pole areas. The pad allows useable flux to be generated at a significant height above a surface of the pad.
1. A magnetic flux pad for loosely coupled inductive power transfer, the pad having a front face and a back face for generating or receiving magnetic flux in or from a space beyond the front face, the pad comprising:
two pole areas,
a magnetically permeable material,
two coils magnetically associated with the magnetically permeable material and each coil defining one of the pole areas, wherein the magnetically permeable material concentrates magnetic flux in the pad between the pole areas whereby magnetic flux is constrained in the permeable material between the pole areas and is guided into and out of the pad via the pole areas to form an arch shaped flux path in the space beyond the front face to transfer power to devices at various distances within the space beyond the front face of the pad.
2. A magnetic flux pad as claimed in claim 1 wherein the coils are flat coils.
3. A magnetic flux pad as claimed in claim 1 wherein the coils are spiral wound coils.
4. A magnetic flux pad as claimed in claim 1 wherein the coils are located on a side of the core nearest to the front face of the pad.
5. A magnetic flux pad as claimed in claim 1 wherein the coils and the magnetically permeable material together form a flux path in the pad.
6. A magnetic flux pad as claimed in claim 1 wherein the magnetically permeable material comprises lengths of permeable material.
7. A magnetic flux pad as claimed in claim 6 wherein the permeable material comprises ferrite.
8. A magnetic flux pad as claimed in claim 1 wherein the coils are each asymmetric, a combination of windings of a coil being wider between the pole areas than at a periphery of the pad.
9. A magnetic flux pad as claimed in claim 1 wherein the coils are located immediately adjacent to each other in the region between the pole areas.
10. A magnetic flux pad as claimed in claim 1 wherein the coils are shaped to provide the poles areas and a flux pipe between the pole areas.
11. A magnetic flux pad for loosely coupled inductive power transfer, the pad having a front face and hack face for generating a magnetic flux in a space beyond the front face of the pad, the pad comprising:
two pole areas for sending or receiving flux,
a magnetically permeable core,
two coils associated with the core and being provided on a side of the core adjacent to the front face of the pad,
whereby the pad produces an arch shaped flux in the space such that essentially each line flux starts on one of the pole areas, arches to the second pole area and joins on itself through the core with essentially no flux present at the back face of the pad to transfer power to devices at various distances within the space beyond the front face of the gad.
12. An IPT system comprising:
a magnetic flux pad for loosely coupled inductive power transfer, the pad having a front face and back face for generating a magnetic flux in a space beyond the front face of the pad to transfer power to devices at various distances within the space beyond the front face of the pad the pad comprising:
two pole areas for sending or receiving flux,
a magnetically permeable core,
two coils associated with the core and being provided on a side of the core adjacent to the front face of the pad,
whereby the pad produces an arch shaped flux in the space such that essentially each line flux starts on one of the pole areas, arches to the second pole area and joins on itself through the core with essentially no flux present at the back face of the pad; and
a magnetic flux pad having a front face and back face for receiving a magnetic flux from a space beyond the front face of the pad, the pad comprising:
two pole areas for sending or receiving flux,
a magnetically permeable core,
two coils associated with the core and being provided on a side of the core adjacent to the front face of the pad and adapted to receive a horizontal flux component,
and a further coil magnetically associated with the core and adapted to receive a vertical flux component.
13. A magnetic flux pad as claimed in claim 2 wherein each coil defines one of the pole areas.
14. A magnetic flux pad as claimed in claim 2 wherein the coils are spiral wound coils.
15. An IPT system including a magnetic flux pad according to claim 11 .
16. An IPT system as claimed in claim 12 for supplying power to an electric vehicle.
17. A magnetic flux pad as claimed in claim 1 wherein at least part of each coil extends beyond the permeable material.
18. A magnetic flux pad as claimed in claim 1 wherein the permeable material has a length dimension extending between the pole areas and a width dimension transverse to the length dimension, and the permeable material does not extend beyond the coils in the width dimension.