Wireless power transfer systems with shield openings

• US 10,186,373 B2
• Filed: 02/01/2018
• Issued: 01/22/2019
• Est. Priority Date: 04/17/2014
• Status: Active Grant

Abstract

In a first aspect, the disclosure features apparatuses for wireless power transfer, the apparatuses including a plurality of magnetic elements joined together to form a magnetic component extending in a plane, where discontinuities in the magnetic component between adjacent magnetic elements define gaps in the magnetic component, a coil including one or more loops of conductive material positioned, at least in part, on a first side of the plane. The apparatuses include a conductive shield positioned on a second side of the plane and which includes one or more openings positioned relative to the gaps.

Claims

1. An apparatus for wireless power transfer, the apparatus comprising:

a plurality of adjacent magnetic elements positioned in a plane and defining a gap;

a coil comprising one or more loops of conductive material positioned, at least in part, on a first side of the plane and on both sides of the gap; and

a conductive shield positioned on a second side of the plane and comprising an opening aligned with the gap.

2. The apparatus of claim 1, wherein the conductive shield is oriented substantially parallel to the plane.

3. The apparatus of claim 1, wherein the gap is not filled with a solid material.

4. The apparatus of claim 1, further comprising a dielectric material positioned in the gap to at least partially fill the gap.

5. The apparatus of claim 1, further comprising a magnetic material having a magnetic permeability different from a magnetic permeability of the magnetic elements and positioned in the gap to at least partially fill the gap.

6. The apparatus of claim 1, wherein the loops are positioned entirely on the first side of the plane.

7. The apparatus of claim 1, wherein:

during operation, the coil generates a magnetic field that oscillates in a first direction parallel to the plane;

the gap corresponds to a spacing between magnetic elements in a direction parallel to the first direction; and

the opening comprises a width that extends in a direction parallel to the first direction.

8. An apparatus for wireless power transfer, the apparatus comprising:

a plurality of adjacent magnetic elements positioned in a plane and defining a gap;

a coil comprising one or more loops of conductive material positioned, at least in part, on a first side of the plane; and

a conductive shield positioned on a second side of the plane and comprising a depression formed in a surface of the shield facing the plane, and aligned with the gap.

9. The apparatus of claim 8, wherein the depression is positioned to reduce interactions between magnetic flux crossing the gap and the conductive shield.

10. The apparatus of claim 8, wherein the coil is positioned entirely on the first side of the plane.

11. The apparatus of claim 8, wherein the one or more loops of conductive material encircle an axis oriented in a direction perpendicular to the plane.

12. The apparatus of claim 8, wherein the depression has a cross-sectional profile that corresponds to at least one of a triangular shape, a trapezoidal shape, and a shape comprising curved edges.

13. The apparatus of claim 8, wherein at least a portion of the conductive shield is oriented parallel to the plane.

14. The apparatus of claim 8, further comprising a dielectric material positioned in the gap.

15. The apparatus of claim 8, further comprising a filler material positioned in the gap, wherein a magnetic permeability of the filler material is different from a magnetic permeability of the plurality of magnetic elements.

16. The apparatus of claim 8, wherein the depression comprises lateral surfaces that are angled relative to the plane.

17. The apparatus of claim 8, wherein:

during operation of the apparatus, the coil generates a magnetic field oscillates in a first direction within the plurality of magnetic elements;

the gap corresponds to a spacing between magnetic elements in a direction parallel to the first direction; and

the depression comprises a width that extends in a direction parallel to the first direction.

18. An apparatus for wireless power transfer, comprising:

a plurality of adjacent planar magnetic elements positioned in a plane and defining a gap in the plane;

a coil comprising one or more loops of conductive material; and

a conductive shield positioned on a second side of the plane and comprising at least one of a depression and an opening formed in a surface of the shield, wherein the at least one of the depression and the opening is aligned with the gap,

wherein the coil is oriented so that during operation of the apparatus, the coil generates an average magnetic field oriented in a first direction parallel to the plane.

19. The apparatus of claim 18, wherein the coil comprises a first plurality of loops and a second plurality of loops connected to the first plurality of loops, and wherein the first and second pluralities of loops are arranged so that during operation of the apparatus, electrical current circulates in a first rotational direction in the first plurality of loops and in a second rotational direction opposite to the first rotational direction in the second plurality of loops.

20. The apparatus of claim 18, wherein a width of the gap extends in a second direction, and wherein an angle between the first and second directions is 10°

or less.