Wireless power transfer with active field cancellation using multiple magnetic flux sinks

Patent metadata

Field	Value
Publication number	US-2021082617-A1
Application number	US-202017023204-A
Country	US
Kind code	A1
Filing date	Sep 16, 2020
Priority date	Sep 16, 2019
Publication date	Mar 18, 2021
Grant date	—

Abstract

A wireless power transfer pad for wireless power transfer with active field cancellation using multiple magnetic flux sinks includes a ferrite structure, a center coil positioned adjacent to the ferrite structure, and a plurality of side coils positioned around a perimeter of the center coil and positioned adjacent to the ferrite structure. A direction of current flow of the center coil is opposite a current flow in each of the plurality of side coils such that current flowing in a portion of the center coil adjacent to a portion of a side coil of the plurality of side coils is in a same direction as current in the portion of the side coil.

First claim

What is claimed is:

1 . A wireless power transfer (“WPT”) pad comprising:
a ferrite structure;
a center coil positioned adjacent to the ferrite structure; and
a plurality of side coils positioned around a perimeter of the center coil and positioned adjacent to the ferrite structure,
wherein a direction of current flow of the center coil is opposite a current flow in each of the plurality of side coils such that current flowing in a portion of the center coil adjacent to a portion of a side coil of the plurality of side coils is in a same direction as current in the portion of the side coil.

2 . The WPT pad of claim 1 , wherein the ferrite structure comprises a planar surface and the center coil and the plurality of side coils are wound parallel to the planar surface.

3 . The WPT pad of claim 1 , wherein, for each side coil of the plurality of side coils, a product of current in the center coil and a number of turns of the center coil is equal to or greater than a product of current in a side coil of the plurality of side coils and a number of turns of the side coil.

4 . The WPT pad of claim 1 , wherein, for a switching frequency of current in the center coil and the plurality of side coils, wherein the direction of current flow of the center coil being opposite the current flow in each of the plurality of side coils comprises current in the center coil being 180 degrees out of phase with current in each of the plurality of side coils.

5 . The WPT pad of claim 1 , wherein the center coil is in a square or rectangular shape in a direction planar to the ferrite structure and has four sides and the plurality of side coils comprises four side coils and each side coil is positioned on a side of the center coil.

6 . The WPT pad of claim 1 , wherein the center coil is circular and each of the plurality of side coils are arc-shaped and are spaced in a circular pattern around the center coil.

7 . The WPT pad of claim 1 , wherein a side of each of the plurality of side coils is next to the center coil and the side coils are evenly spaced around the center coil.

8 . The WPT pad of claim 1 , further comprising a converter connected to the center coil and each of the plurality of side coils, wherein the converter provides current to the center coil and each of the plurality of side coils and wherein the converter controls current to the center coil and plurality of side coils.

9 . The WPT pad of claim 8 , wherein the center coil and the plurality of side coils are connected in series.

10 . The WPT pad of claim 8 , wherein the converter comprises a first converter section that provides current to the center coil and a second converter section that provides current to the plurality of side coils, wherein a current output of the first converter section is equal to or greater than a current output of the second converter section and wherein the current output of the second converter section is split equally between the plurality of side coils.

11 . The WPT pad of claim 1 , further comprising:
a position sensor configured to sense offset of a receiver with respect to the center coil in a direction away from a center of the center coil; and a field modifier configured to reduce current in a side coil of the plurality of side coils in the direction of the offset of the receiver and to increase current in a side coil of the plurality of side coils opposite the direction of the offset of the receiver.

12 . The WPT pad of claim 11 , wherein the offset of the receiver is in a direction from the center of the center coil and forms a first direction vector with an angle that is between two vectors toward each of two side coils of the plurality of side coils and the field modifier reduces current in the two side coils, and wherein a second direction vector opposite the first direction vector is between two vectors toward each of two additional side coils of the plurality of side coils and the field modifier increases current in the two additional side coils.

13 . A wireless power transfer (“WPT”) pad comprising:
a ferrite structure comprising a planar surface;
a center coil positioned adjacent to the ferrite structure; and
a plurality of side coils positioned around a perimeter of the center coil and positioned adjacent to the ferrite structure, wherein the center coil and the plurality of side coils are wound parallel to the planar surface of the ferrite structure, a side of each of the plurality of side coils is next to the center coil and the side coils are evenly spaced around the center coil,
wherein a direction of current flow of the center coil is opposite a current flow in each of the plurality of side coils such that current flowing in a portion of the center coil adjacent to a portion of a side coil of the plurality of side coils is in a same direction as current in the portion of the side coil, and
wherein, for each side coil of the plurality of side coils, a product of current in the center coil and a number of turns of the center coil is equal to or greater than a product of current in a side coil of the plurality of side coils and a number of turns of the side coil.

14 . The WPT pad of claim 13 , wherein, for a switching frequency of current in the center coil and the plurality of side coils, wherein the direction of current flow of the center coil being opposite the current flow in each of the plurality of side coils comprises current in the center coil being 180 degrees out of phase with current in each of the plurality of side coils.

15 . The WPT pad of claim 13 , further comprising a converter connected to the center coil and each of the plurality of side coils, wherein the converter provides current to the center coil and each of the plurality of side coils and wherein the converter controls current to the center coil and plurality of side coils.

16 . The WPT pad of claim 15 , wherein the center coil and the plurality of side coils are connected in series.

17 . The WPT pad of claim 15 , wherein the converter comprises a first converter section that provides current to the center coil and a second converter section that provides current to the plurality of side coils, wherein a current output of the first converter section is equal to or greater than a current output of the second converter section and wherein the current output of the second converter section is split equally between the plurality of side coils.

18 . The WPT pad of claim 13 , further comprising:
a position sensor configured to sense offset of a receiver with respect to the center coil in a direction away from a center of the center coil; and a field modifier configured to reduce current in a side coil of the plurality of side coils in the direction of the offset of the receiver and to increase current in a side coil of the plurality of side coils opposite the direction of the offset of the receiver.

19 . The WPT pad of claim 18 , wherein the offset of the receiver is in a direction from the center of the center coil and forms a first direction vector with an angle that is between two vectors toward each of two side coils of the plurality of side coils and the field modifier reduces current in the two side coils, and wherein a second direction vector opposite the first direction vector is between two vectors toward each of two additional side coils of the plurality of side coils and the field modifier increases current in the two additional side coils.

20 . A system comprising:
a ferrite structure; a center coil posi

Assignees

• Univ Utah State

Inventors

• Varghese Benny J
• Kamineni Abhilash
• Zane Regan A

Classifications

• Y02T10/70

  Energy storage systems for electromobility, e.g. batteries · CPC title

• Y02T90/14

  Plug-in electric vehicles · CPC title

• Y02T10/7072

  Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors · CPC title

• H02J50/402

  the two or more transmitting or the two or more receiving devices being integrated in the same unit, e.g. power mats with several coils or antennas with several sub-antennas · CPC title

• H02J50/005

  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 title