Double-D based pad magnetics for reduced emissions in flush mounted and buried wireless power transfer applications

• US 10,404,100 B2
• Filed: 06/15/2016
• Issued: 09/03/2019
• Est. Priority Date: 06/15/2016
• Status: Active Grant

• Current Assignee: WiTricity Corporation
• Original Assignee: WiTricity Corporation
• Inventors: Werner, Michael
• Primary Examiner(s): Barnie, Rexford N
• Assistant Examiner(s): Parries, Dru
• Application Number:
  US15/183,394
• Publication Number:
  US 20170366046A1
• Time in Patent Office: 1,175 Days
• Field of Search: 307104
• CPC Class Codes: B60L 53/122 Circuits or methods for driving the primary coil, e.g. supplying electric power to the coil
• CPC Class Codes: H01F 27/2823 Wires H01F27/2866 takes precedence
• CPC Class Codes: H01F 27/2871 Pancake coils
• CPC Class Codes: H01F 27/36 Electric or magnetic shields or screens movable for varying inductance H01F21/10
• CPC Class Codes: H01F 27/366 made of ferromagnetic material
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: H02J 50/005 Mechanical details of housing or structure aiming to accommodate the power transfer means, e.g. mechanical integration of coils, antennas or transducers into emitting or receiving devices
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• CPC Class Codes: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
• CPC Class Codes: H02J 7/0042 characterised by the mechanical construction
• CPC Class Codes: H04B 5/24 Inductive coupling
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 90/12 Electric charging stations
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles

Abstract

An apparatus for wirelessly transferring charging power is provided. The apparatus comprises a ferrite structure. The apparatus comprises a first coil comprising a first conductor wound in a first layer at an outer side of the first coil and wound in a first plurality of stacked layers on an inner side of the first coil. At least one layer of the first plurality of stacked layers on the inner side of the first coil is recessed into the ferrite structure. The apparatus comprises a second coil comprising a second conductor wound in a second layer at an outer side of the second coil and wound in a second plurality of stacked layers on an inner side of the second coil. At least one layer of the second plurality of stacked layers on the inner side of the second coil recessed into the ferrite structure.

Claims

1. An apparatus for wirelessly transferring charging power, comprising:

a ferrite structure;

a first coil comprising a first conductor wound in a first layer at an outer side of the first coil and wound in a first plurality of stacked layers on an inner side of the first coil, at least one layer of the first plurality of stacked layers on the inner side of the first coil recessed into the ferrite structure; and

a second coil comprising a second conductor wound in a second layer at an outer side of the second coil and wound in a second plurality of stacked layers on an inner side of the second coil, at least one layer of the second plurality of stacked layers on the inner side of the second coil recessed into the ferrite structure.

2. The apparatus of claim 1, wherein the first coil and the second coil form at least a portion of a double D coil configuration.

3. The apparatus of claim 1, wherein successive windings of the first coil are separated by a nonzero distance at the outer side of the first coil and successive windings of the second coil are separated by a nonzero distance at the outer side of the second coil.

4. The apparatus of claim 1, wherein successive windings of the first coil are substantially in physical contact at the outer side of the first coil and successive windings of the second coil are substantially in physical contact at the outer side of the second coil.

5. The apparatus of claim 1, wherein the ferrite structure, the first coil and the second coil are buried below a driving surface.

6. The apparatus of claim 1, wherein the ferrite structure, the first coil and the second coil are flush mounted in a driving surface.

7. The apparatus of claim 1, wherein the ferrite structure extends laterally beyond edges of the first coil and the second coil to form a ferrite border along an entire perimeter of the first coil and the second coil.

8. The apparatus of claim 1, wherein one or both of the first layer and the second layer comprises a single layer.

9. The apparatus of claim 1, wherein at least one of:

the first layer at the outer side of the first coil is wider than the first plurality of stacked layers on the inner side of the first coil; and

the second layer at the outer side of the second coil is wider than the second plurality of stacked layers on the inner side of the second coil.

10. The apparatus of claim 1, further comprising at least one driver configured to provide current to the first coil and to the second coil, such that current on the inner side of the first coil travels in the same direction as current on the inner side of the second coil.

12. The apparatus of claim 1, wherein the ferrite structure overlaps the outer side and the inner side of the first coil, the ferrite structure further overlapping the outer side and the inner side of the second coil.

13. The apparatus of claim 1, wherein the second coil is positioned coplanar relative to the first coil wherein the inner side of the first coil is positioned adjacent to the inner side of the second coil.

11. A method for wirelessly transferring charging power, comprising:

driving each of a first coil and a second coil with a current to generate an alternating magnetic field; and

wirelessly transferring charging power to at least one vehicle pad via the alternating magnetic field, wherein;

the first coil comprises a first conductor wound in a first layer at an outer side of the first coil and wound in a first plurality of stacked layers on an inner side of the first coil, at least one layer of the first plurality of stacked layers on the inner side of the first coil recessed into a ferrite structure, and

the second coil comprises a second conductor wound in a second layer at an outer side of the second coil and wound in a second plurality of stacked layers on an inner side of the second coil, at least one layer of the second plurality of stacked layers on the inner side of the second coil recessed into the ferrite structure.

14. An apparatus for wirelessly transferring charging power, comprising:

a first coil comprising a first plurality of conductive windings wound about a first opening, wherein the first plurality of conductive windings are wound in a first plurality of stacked layers on a first side of the first coil wherein the number of layers on the first side of the first coil is greater than the number of layers on a second side of the first coil; and

a second coil positioned substantially co-planar with the first coil and comprising a second plurality of conductive windings wound about a second opening, wherein the second plurality of conductive windings are wound in a second plurality of stacked layers on a third side of the second coil wherein the number of layers on the third side of the second coil is greater than the number of layers on a fourth side of the second coil, wherein the first side of the first coil is positioned closer to the third side of the second coil than to the fourth side of the second coil; and

a ferrite structure overlapping at least a portion of the first coil and the second coil.

15. The apparatus of claim 14, wherein at least a portion of the first plurality of stacked layers are recessed into the ferrite structure.

16. The apparatus of claim 14, wherein the number of layers on the second side of the first coil, and/or the number of layers on the second side of the second coil, is one.

17. The apparatus of claim 14, wherein the first coil is laterally displaced from the second coil such that the first side of the first coil is adjacent to the third side of the second coil.

18. The apparatus of claim 14, further comprising at least one driver configured to provide current to the first coil and to the second coil, such that current on the first side of the first coil travels in the same direction as current on the third side of the second coil.

19. The apparatus of claim 14, further comprising a resonant circuit comprising the first and second coil.

20. The apparatus of claim 14, wherein successive windings of the first coil are separated by a nonzero distance at the second side of the first coil and successive windings of the second coil are separated by a nonzero distance at the fourth side of the second coil.

21. The apparatus of claim 14, wherein the ferrite structure extends laterally beyond edges of the first coil and the second coil to form a ferrite border along an entire perimeter of the first coil and the second coil.

22. The apparatus of claim 14, wherein at least one of:

the first layer at the second side of the first coil is wider than the first plurality of stacked layers on the first side of the first coil; and

the second layer at the fourth side of the second coil is wider than the second plurality of stacked layers on the third side of the second coil.

23. The apparatus of claim 14, wherein the ferrite structure overlaps the first side and the second side of the first coil, the ferrite structure further overlapping the first side and the second side of the second coil.