MAGNETIC FIELD CONFIGURATION FOR A WIRELESS ENERGY TRANSFER SYSTEM

• US 20170093215A1
• Filed: 10/25/2016
• Published: 03/30/2017
• 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
• Granted Patent: US 10,389,177 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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 wireless power receiver further comprising a plurality of receiver magnetic field generating units;

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

wherein said plurality of magnetic field generating units in the wireless power transmitter and wireless power receiver are arranged in an array such that the magnetic field strength 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 1, wherein the plurality of transmitter magnetic field generating units comprises a first Halbach array and the plurality of receiver magnetic field generating units comprises a second Halbach array.

15. 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.

16. 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.

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 a permanent magnet and at least one of the receiver magnetic field generating units comprises a permanent magnet.

18. 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 and at least one of the receiver magnetic field generating units comprises an electromagnetic coil.

19. A magnetically-coupled wireless power transfer system according to claim 17, 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.

20. 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.

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

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

23. A magnetically-coupled wireless power transfer system according to claim 22, 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.

24. A magnetic induction wireless power transfer system, comprising:

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

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

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

wherein said plurality of transmitter magnetic field generating units and said plurality of receiver magnetic field generating units are arranged in arrays such that the magnetic field strength 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.

25. A magnetic induction wireless power transfer system comprising:

a transmitter comprising a plurality of transmitter magnetic field generating units, each magnetic field generating unit comprising one or more transmitter coils arranged to cause;

a first transmitter magnetization direction in the transmitter magnetic field generating unit in response to a first current driven into the one or more transmitter coils of the transmitter magnetic field generating unit in a first transmitter current direction; and

a second transmitter magnetization direction in the transmitter magnetic field generating unit, opposing the first transmitter magnetization direction, in response to a second current driven into the one or more transmitter coils of the transmitter magnetic field generating unit in a second transmitter current direction;

wherein the first transmitter magnetization directions of the transmitter magnetic field generating units vary along a transmitter magnetization-variation direction; and

a receiver comprising one or more receiver coil units, each receiver coil unit comprising one or more receiver coils, the receiver separated from the transmitter by an air gap;

wherein switching between the first current and the second current induces current in the one or more receiver coils.

26. A magnetic induction wireless power transfer system according to claim 25, wherein a strength of a magnetic field generated by the transmitter is greater in the air gap between the transmitter and receiver than a strength of the magnetic field generated by the transmitter outside the air gap.

27. A magnetic induction wireless power transfer system according to claim 25, wherein the first transmitter magnetization directions of transmitter magnetic field generating units adjacent to one another in the transmitter magnetization-variation direction are different from one another.

28. A magnetic induction wireless power transfer system according to claim 25, wherein each of the first transmitter magnetization directions is orthogonal to a corresponding transmitter uniform-magnetization direction and the transmitter magnetization-variation direction is orthogonal to each of the transmitter uniform-magnetization directions.

29. A magnetic induction wireless power transfer system according to claim 25, wherein the variation of the first transmitter 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 in the transmitter magnetization-variation direction, where λ

₁ equals the number of transmitter magnetic field generating units in the first period.

30. A magnetic induction wireless power transfer system according to claim 29, wherein the number, λ

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

31. A magnetic induction wireless power transfer system according to claim 30, wherein angular orientations of the first transmitter 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.

32. A magnetic induction wireless power transfer system according to claim 31, 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°

.

33. A magnetic induction wireless power transfer system according to claim 30, 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.

34. A magnetic induction wireless power transfer system according to claim 25, wherein the plurality of transmitter magnetic field generating units are arranged in a first Halbach array configuration.

35. A magnetic induction wireless power transfer system according to claim 25, wherein each of the one or more receiver coil units are arranged to cause a first receiver magnetization direction in the receiver coil unit in response to a first current induced into the receiver coil unit in a first receiver current direction and a second receiver magnetization direction in the receiver coil unit, opposing the first receiver magnetization direction, in response to a second current induced into the receiver coil unit in a second receiver current direction, wherein the first receiver magnetization directions of the receiver coil units vary along a receiver magnetization-variation direction.