Magnetic field configuration for a wireless energy transfer system

• US 10,389,177 B2
• Filed: 10/25/2016
• Issued: 08/20/2019
• Est. Priority Date: 04/26/2014
• Status: Active Grant

• Current Assignee: ELIX Wireless Charging Systems Inc.
• Original Assignee: ELIX Wireless Charging Systems Inc.
• Inventors: Ng, Boon
• Primary Examiner(s): Barnie, Rexford N
• Assistant Examiner(s): Ortiz, Elim
• Application Number:
  US15/334,075
• Publication Number:
  US 20170093215A1
• Time in Patent Office: 1,029 Days
• CPC Class Codes: H01F 1/057 and IIIa elements, e.g. Nd2Fe14B
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: H01F 7/021 Construction of PM H01F7/0278 takes precedence; PM compositions H01F1/032
• CPC Class Codes: H01F 7/0273 Magnetic circuits with PM for magnetic field generation
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/402 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 Class Codes: H02J 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• CPC Class Codes: H02K 47/18 AC/AC converters
• CPC Class Codes: H02K 7/11 with dynamo-electric clutches

Abstract

Wireless power transfer systems comprising of special arrangements of magnetic field generating materials within the wireless power transmitter and the wireless power receiver. The arrangement enables a greater amount of the magnetic field to be contained within the air gap between the wireless power transmitter and the wireless power receiver than outside of the air gap.

Claims

1. A magnetically-coupled wireless power transfer system, comprising:

a wireless power transmitter further comprising a plurality of transmitter magnetic field generating units;

a first time-varying magnetic field created by the wireless power transmitter;

a wireless power receiver further comprising a plurality of receiver magnetic field generating units, the plurality of receiver magnetic field generating units located in the first time-varying magnetic field and supported to permit rotation about a receiver axis in response to the first time-varying magnetic field;

an air gap separating the wireless power transmitter and wireless power receiver;

wherein said plurality of transmitter magnetic field generating units in the wireless power transmitter are arranged in a first Halbach array and said plurality of receiver magnetic field generating units in the wireless power receiver are arranged in a second Halbach array; and

wherein said arrangement of the plurality of transmitter magnetic field generating units in the wireless power transmitter in the first Halbach array and said arrangement of the plurality of receiver magnetic field generating units in the wireless power receiver in the second Halbach array provide a combined magnetic field, wherein a magnetic field strength of the combined magnetic field is greater in the air gap between the wireless power transmitter and wireless power receiver than the magnetic field strength outside of the air gap separating the wireless power transmitter and wireless power receiver.

2. A magnetically-coupled wireless power transfer system according to claim 1, wherein:

each of the plurality of transmitter magnetic field generating units exhibits predominantly a corresponding first magnetization direction and the first magnetization directions of the plurality of transmitter magnetic field generating units vary along a transmitter magnetization-variation direction; and

each of the plurality of receiver magnetic field generating units exhibits predominantly a corresponding second magnetization direction and the second magnetization directions of the plurality of receiver magnetic field generating units vary along a receiver magnetization-variation direction.

3. A magnetically-coupled wireless power transfer system according to claim 2, wherein

the first magnetization directions of transmitter magnetic field generating units adjacent to one another in the transmitter magnetization-variation direction are different from one another;

and

the second magnetization directions of receiver magnetic field generating units adjacent to one another in the receiver magnetization-variation direction are different from one another.

4. A magnetically-coupled wireless power transfer system according to claim 2, wherein each of the first magnetization directions is orthogonal to a corresponding transmitter uniform-magnetization direction and each of the second magnetization directions is orthogonal to a corresponding receiver uniform-magnetization direction.

5. A magnetically-coupled wireless power transfer system according claim 2, wherein the transmitter magnetization-variation direction is orthogonal to each of the transmitter uniform-magnetization directions and the receiver magnetization-variation direction is orthogonal to each of the receiver uniform-magnetization directions.

6. A magnetically-coupled wireless power transfer system according to claim 2, wherein the first magnetization direction of each transmitter magnetic field generating unit is constant along its corresponding transmitter uniform-magnetization direction and the second magnetization direction of each receiver magnetic field generating unit is constant along its corresponding receiver uniform-magnetization direction.

7. A magnetically-coupled wireless power transfer system according to claim 3, wherein the first magnetization direction of each transmitter magnetic field generating unit is constant within the transmitter magnetic field generating unit and the second magnetization direction of each receiver magnetic field generating unit is constant within the receiver magnetic field generating unit.

8. A magnetically-coupled wireless power transfer system according to claim 2, wherein the variation of the first magnetization directions of the transmitter magnetic field generating units exhibits a first spatially periodic pattern along the transmitter magnetization-variation direction, the first spatially periodic pattern having a first period λ

₁ in the transmitter magnetization-variation direction, where λ

₁ equals the number of transmitter magnetic field generating units in the first period, and the variation of the second magnetization directions of the receiver magnetic field generating units exhibits a second spatially periodic pattern along the receiver magnetization-variation direction, the second spatially periodic pattern having a second period λ

₂ in the receiver magnetization-variation direction, where λ

₂ equals the number of receiver magnetic field generating units in the second period.

9. A magnetically-coupled wireless power transfer system according to claim 8, wherein the number, λ

₁, of transmitter magnetic field generating units in the first period comprises four or more transmitter magnetic field generating units and the number, λ

₂, of receiver magnetic field generating units in the second period comprises four or more receiver magnetic field generating units.

10. A magnetically-coupled wireless power transfer system according to claim 3, wherein the variation of the first magnetization directions of the transmitter magnetic field generating units exhibits a first spatially periodic pattern along the transmitter magnetization-variation direction, the first spatially periodic pattern having a first period λ

₁ in the transmitter magnetization-variation direction, where λ

₁ equals the number of transmitter magnetic field generating units in the first period, and the variation of the second magnetization directions of the receiver magnetic field generating units exhibits a second spatially periodic pattern along the receiver magnetization-variation direction, the second spatially periodic pattern having a second period λ

₂ in the receiver magnetization-variation direction, where λ

₂ equals the number of receiver magnetic field generating units in the second period and wherein angular orientations of the first magnetization directions of transmitter magnetic field generating units adjacent to one another in the transmitter magnetization-variation direction about their corresponding transmitter uniform-magnetization directions differ from one another by a first angular offset, α

₁, and angular orientations of the second magnetization directions of receiver magnetic field generating units adjacent to one another in the receiver magnetization-variation direction about their corresponding receiver uniform-magnetization directions differ from one another by a second angular offset, α

₂.

11. A magnetically-coupled wireless power transfer system according to claim 10, wherein the first angular offset, α

₁ is equal to the second angular offset, α

₂.

12. A magnetically-coupled wireless power transfer system according to claim 10, wherein the number, λ

₁, of transmitter magnetic field generating units in the first period multiplied by the first angular offset, α

₁, is equal to 360° and

the number, λ

₂, of receiver magnetic field generating units in the second period multiplied by the second angular offset, α

₂, is equal to 360°

.

13. A magnetically-coupled wireless power transfer system according to claim 9, wherein the plurality of transmitter magnetic field generating units comprises a positive integer multiple of the number, λ

₁, of transmitter magnetic field generating units in the first period and the plurality of receiver magnetic field generating units comprises a positive integer multiple of the number, λ

₂, of receiver magnetic field generating units in the second period.

14. A magnetically-coupled wireless power transfer system according to claim 2, wherein:

the wireless power transmitter and the wireless power receiver are each cylindrical in shape; and

the transmitter magnetic field generating units and the receiver magnetic field generating units are each generally wedge-shaped.

15. A magnetically-coupled wireless power transfer system according to claim 2, wherein:

the transmitter uniform-magnetization directions are radial about a cylinder axis of the wireless power transmitter and the receiver uniform-magnetization directions are radial about a cylinder axis of the wireless power receiver; and

the transmitter magnetization-variation direction is circular about the cylinder axis of the wireless power transmitter and the receiver magnetization-variation direction is circular about the cylinder axis of the wireless power receiver.

16. A magnetically-coupled wireless power transfer system according to claim 2, wherein at least one of the plurality of transmitter magnetic field generating units comprises a permanent magnet and at least one of the receiver magnetic field generating units comprises a permanent magnet.

17. A magnetically-coupled wireless power transfer system according to claim 2, wherein at least one of the plurality of transmitter magnetic field generating units comprises an electromagnetic coil.

18. A magnetically-coupled wireless power transfer system according to claim 16, wherein the permanent magnets comprises NdFeB, samarium cobalt, magnetite, ferrite or an alloy comprising three or more of iron, aluminum, nickel, cobalt, titanium and copper or a combination thereof.

19. A magnetically-coupled wireless power transfer system according to claim 1, wherein the wireless power transmitter comprises at least one of:

a rotor mechanically connected to a motor to move the wireless power transmitter about a transmitter axis; and

a plurality of current carrying coils arranged in proximity to the transmitter magnetic field generating units to move the wireless power transmitter about a transmitter axis via magnetic interaction.

20. A magnetically-coupled wireless power transfer system according to claim 1, wherein the wireless power receiver is magnetically coupled to the wireless power transmitter.

21. A magnetically-coupled wireless power transfer system according to claim 20, wherein the wireless power receiver rotates in response to a rotation of the wireless power transmitter.

22. A magnetically-coupled wireless power transfer system according to claim 21, wherein the rotation of the wireless power receiver induces a time-varying current in electrical current-carrying coils that are in close proximity to the receiver.