Magnetically permeable core and inductive power transfer coil arrangement
An inductive power transfer coil arrangement comprising: a first coil assembly including: at least a first magnetically permeable core including a base having first and second limbs extending away therefrom, wherein the first limb is located between two second limbs and extends further from the base than the second limbs, and at least one coil wound about at least one limb; and a second coil assembly including: at least a second magnetically permeable core for use in an inductive power transfer system, including a base having first and second limbs extending away therefrom, wherein the first limb is located between two second limbs that extend further from the base than the second limbs; and at least one coil wound about at least one limb; the first and second magnetically permeable cores being arranged in relatively moveable relationship such that in some relative positions the first and second magnetically permeable cores are opposed such as to provide effective magnetic coupling.
1. An inductive power transfer coil arrangement comprising:
i. a first coil assembly including:
a. at least a first magnetically permeable core including a base having first and second limbs extending away therefrom, wherein the first limb is located between two of the second limbs and extends further from the base than the second limbs, and
b. at least one coil wound about at least one of the limbs; and
ii. a second coil assembly including:
a. at least a second magnetically permeable core including a base having first and second limbs extending away therefrom, wherein the first limb is located between two second limbs and extends further from the base than the second limbs; and
b. at least one coil wound about at least one of the limbs,
the first and second magnetically permeable cores arranged to be relatively moveable wherein in some relative positions the first and second magnetically permeable cores are opposed such as to provide effective magnetic coupling.
2. An inductive power transfer coil arrangement as claimed in claim 1 wherein the first and second magnetically permeable cores are arranged along respective annular paths.
3. An inductive power transfer coil arrangement as claimed in claim 2 wherein the first and second coil assemblies each includes a plurality of cores.
4. An inductive power transfer coil arrangement as claimed in claim 1 wherein each of the first and/or second magnetically permeable cores is an annular core.
5. An inductive power transfer coil 4 arrangement as claimed in claim 1 wherein the first and second coil assemblies are axially opposed.
6. An inductive power transfer coil arrangement as claimed in claim 1 wherein the first and second coil assemblies are concentrically arranged.
7. An inductive power transfer coil arrangement as claimed in claim 2 having a through hole at the centre of the annular path.
8. An inductive power transfer coil arrangement as claimed in claim 1 wherein the second limbs are less than about 90% of the length of the first limb.
9. An inductive power transfer coil arrangement as claimed in claim 1 wherein the second limbs are less than about 80% of the length of the first limb.
10. An inductive power transfer coil arrangement as claimed in claim 1 wherein the second limbs are between about 20% and about 80% of the length of the first limb.
11. An inductive power transfer coil arrangement as claimed in claim 1 wherein the second limbs are between about 40% and about 60% of the length of the first limb.
12. An inductive power transfer coil arrangement as claimed in claim 1 wherein the second limbs are about 50% of the length of the first limb.
13. An inductive power transfer coil arrangement as claimed in claim 1 wherein the transition from the base to each limb is curved.
14. A magnetically permeable core for use in an inductive power transfer system, including a base having one or more first annular limbs and two or more second annular limbs extending away from the base, the one or more first annular limbs being located between the second annular limbs and extending further from the base than the second annular limbs, wherein the core is a unitary annular core.
15. A magnetically permeable core assembly for use in an inductive power transfer system, the assembly including a plurality of cores, each core including a base having one or more first limbs and two or more second limbs arranged along annular paths and extending away from the base, the one or more first limbs being located between the second limbs and extending further from the base than the second limbs, wherein the plurality of cores are arranged along an annular path.
16. A magnetically permeable core assembly as claimed in claim 15 including a winding wound following the annular path along which the plurality of cores are arranged.