Enclosures for high power wireless power transfer systems
The disclosure features wireless power devices for receiving power from a wireless power source. The devices include a first plurality of magnetic material pieces of substantially planar shape arranged in a first plane, where the first plurality of magnetic material pieces have a first planar surface and a second planar surface. The devices include a device resonator comprising at least one wound conductor disposed on the first planar surface and a second plurality of magnetic material pieces in a second plane, where at least one of the second plurality of magnetic material pieces overlaps at least one of the first plurality of magnetic material pieces and where a separation between the first and second planes is less than 2 mm.
1. A wireless power device for a vehicle, and for receiving power from a wireless power source comprising a source resonator, the wireless power device comprising:
a first plurality of magnetic material pieces arranged in a first plane, wherein the first plurality of magnetic material pieces have a first planar surface and a second planar surface;
a device resonator comprising at least one wound conductor disposed on the first planar surface; and
a second plurality of magnetic material pieces in a second plane, wherein at least one of the second plurality of magnetic material pieces overlaps at least one of the first plurality of magnetic material pieces;
wherein a separation between the first and second planes is less than 2 mm; and
wherein the first and second pluralities of magnetic material pieces form a low-reluctance pathway, relative to air, for magnetic flux received by the device resonator.
2. The wireless power device of claim 1 wherein the separation between the first and second planes is less than 0.5 mm.
3. The wireless power device of claim 2 wherein a coupling k between the device resonator and the source resonator is at least 5% greater than the coupling k that would occur between the device resonator and the source resonator in absence of the second plurality of magnetic material pieces.
4. The wireless power device of claim 2 wherein a coupling k between the device resonator and the source resonator is at least 10% greater than the coupling k that would occur between the device resonator and the source resonator in absence of the second plurality of magnetic material pieces.
5. The wireless power device of claim 1 wherein the separation between the first and second planes is uniform.
6. The wireless power device of claim 1 wherein the separation is maintained using a plastic spacer between the first plurality and the second plurality of magnetic material pieces.
7. The wireless power device of claim 1 wherein an overlap between the at least one of the second plurality of magnetic material pieces and the at least one of the first plurality of magnetic material pieces is equal to or greater than 8 mm.
8. The wireless power device of claim 1 wherein an overlap between the at least one of the second plurality of magnetic material pieces and the at least one of the first plurality of magnetic material pieces is within a factor of 10 of a thickness of the first plurality of magnetic material pieces or the second plurality of magnetic material pieces.
9. The wireless power device of claim 5 wherein the first plurality of magnetic material pieces each have a thickness between and including 5 mm to 8 mm.
10. The wireless power device of claim 5 wherein the second plurality of magnetic material pieces each have a thickness between and including 2 mm to 5 mm.
11. The wireless power device of claim 1 wherein a coupling k between the device resonator and the source resonator is at least 5% greater than the coupling k that would occur between the device resonator and the source resonator in absence of the second plurality of magnetic material pieces.
12. The wireless power device of claim 1 wherein a coupling k between the device resonator and the source resonator is at least 10% greater than the coupling k that would occur between the device resonator and the source resonator in absence of the second plurality of magnetic material pieces.
13. The wireless power device of claim 1 wherein a gap in the second plurality of pieces near a center of the at least one wound conductor is 0.5 mm or greater.
14. The wireless power device of claim 1 wherein the at least one conductor is wound in the second plane.
15. The wireless power device of claim 1 further comprising a capacitor network coupled to the at least one wound conductor is positioned under the second plurality of magnetic material pieces.
16. The wireless power device of claim 15 further comprising a conductor piece positioned between the second plurality of magnetic material pieces and the capacitor network.
17. The wireless power device of claim 1 further comprising an aluminum shield positioned adjacent to the first plurality of magnetic material pieces opposite the at least one conductor.
18. The wireless power device of claim 17 wherein the aluminum shield is attached to an underside of a vehicle.