Wireless non-radiative energy transfer

• US 9,831,722 B2
• Filed: 03/29/2016
• Issued: 11/28/2017
• Est. Priority Date: 07/12/2005
• Status: Active Grant

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Joannopoulos, John D., Karalis, Aristeidis, Soljacic, Marin
• Primary Examiner(s): Fleming, Fritz M
• Application Number:
  US15/083,726
• Publication Number:
  US 20160380481A1
• Time in Patent Office: 609 Days
• Field of Search: 307104, 320108
• CPC Class Codes: B60L 53/126 Methods for pairing a vehicle and a charging station, e.g. establishing a one-to-one relation between a wireless power transmitter and a wireless power receiver
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: H01Q 9/04 Resonant antennas
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/40 using two or more transmitting or receiving devices H02J50/50 takes precedence
• CPC Class Codes: H02M 1/0064 Magnetic structures combining different functions, e.g. storage, filtering or transformation
• CPC Class Codes: H02M 3/01 Resonant DC/DC converters
• 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

Described herein are embodiments of a source high-Q resonator, optionally coupled to an energy source, a second high-Q resonator, optionally coupled to an energy drain that may be located a distance from the source resonator. A third high-Q resonator, optionally coupled to an energy drain that may be located a distance from the source resonator. The source resonator and at least one of the second resonator and third resonator may be coupled to transfer electromagnetic energy from said source resonator to said at least one of the second resonator and third resonator.

Claims

1. A wireless power system comprising:

a source resonator configured to be coupled to a power supply to provide power to the source resonator, the source resonator having a resonant frequency ω

₁, an intrinsic loss rate Γ

₁, and capable of storing electromagnetic energy with an intrinsic quality factor Q₁=ω

₁/(2Γ

₁), the source resonator comprising at least one loop of conductive material and further comprising a capacitance; and

a device resonator and a load coupled to the device resonator to receive power from the device resonator, the device resonator having a resonant frequency ω

₂, an intrinsic loss rate Γ

₂, and capable of storing electromagnetic energy with an intrinsic quality factor Q₂=ω

₂/(2Γ

₂), the device resonator comprising at least one loop of conductive material and further comprising a capacitance,

wherein the source resonator and the device resonator are configured to resonantly and wirelessly couple electromagnetic power from the source resonator to the device resonator over a range of distances D between the source and device resonators using non-radiative electromagnetic induction having a coupling coefficient κ

,

wherein Q₁>

200 and Q₂>

200, and

wherein the source resonator and the device resonator each have a characteristic size, and wherein the characteristic size of the source resonator is not more than 100/30 times the characteristic size of the device resonator.

2. The wireless power system of claim 1, wherein the intrinsic loss rates satisfy κ

/√

{square root over (Γ

₁Γ

₂)}>

5 over the range of distances D.

3. The wireless power system of claim 1, wherein Q₁>

500 and Q₂>

500.

4. The wireless power system of claim 1, wherein the power provided to the load from the device resonator defines a work drainage rate Γ

_w, and wherein the work drainage rate Γ

_w is configured to be dynamically set as a function of the coupling coefficient κ

between the source and device resonators over the range of distances D.

5. The wireless power system of claim 4, wherein the work drainage rate Γ

_w is configured to be dynamically set such that the ratio of useful-to-lost power is maximized as a function of the-coupling coefficient κ

over the range of distances D.

6. The wireless power system of claim 4, wherein the work drainage rate Γ

_w is configured to be dynamically set such that Γ

_w=Γ

₂ √

{square root over (1+(κ

²/Γ

₁·

Γ

₂))} as a function of the coupling coefficient κ

over the range of distances D.

7. The wireless power system of claim 1, wherein the power provided to the load from the device resonator defines a work drainage rate Γ

_w, and wherein the work drainage rate Γ

_w is configured to be set such that Γ

_w=Γ

₂ √

{square root over (1+(κ

²/Γ

₁·

Γ

₂))} for some value of the coupling coefficient κ

in the range of distances D.

8. The wireless power system of claim 1, wherein the power provided to the load from the device resonator defines a work drainage rate Γ

_w, and wherein the work drainage rate Γ

_w is configured to be set such that the ratio of useful-to-lost power is maximized for some value of the-coupling coefficient κ

in the range of distances D.

9. The wireless power system of claim 8, wherein the work drainage rate Γ

_w is configured to be set such that Γ

_w=Γ

₂√

{square root over (1+(κ

²/Γ

₁·

Γ

₂))} for said value of the coupling coefficient κ

in the range of distances D.

10. The wireless power system of claim 1, wherein the power provided to the load from the device resonator defines a work drainage rate Γ

_w, and wherein the work drainage rate Γ

_w is configured to be set such that Γ

_w>

Γ

₂.

11. The wireless power system of claim 1, wherein the load is configured to provide power to a vehicle.

12. A wireless power system comprising:

a source resonator and a power supply coupled to the source resonator to provide power to the source resonator, the source resonator having a resonant frequency cm, an intrinsic loss rate Γ

₁, and an intrinsic quality factor Q₁=ω

₁/(2Γ

₁); and

a device resonator and a load coupled to the device resonator to receive power from the device resonator, the device resonator having a resonant frequency ω

₂, an intrinsic loss rate Γ

₂, and an intrinsic quality factor Q₂=ω

₂/(2Γ

₂),

wherein the source resonator and the device resonator are configured to resonantly and wirelessly couple electromagnetic power from the source resonator to the device resonator over a range of distances D between the source resonator and the device resonator using non-radiative electromagnetic induction having a coupling coefficient κ

, and wherein the intrinsic loss rates satisfy κ

/√

{square root over (Γ

₁Γ

₂)}>

2 over the range of distances D between the source resonator and the device resonator,

wherein Q₁>

100 and Q₂>

100, and

wherein f₁=ω

₁/(2π

) and f₂=ω

₂/(2π

), and f₁ and f₂, are between 1 MHz and 10 MHz, and wherein each intrinsic loss rate comprises a resistive component and a radiative component.

13. The wireless power system of claim 12, further comprising a portable electronic device comprising the device resonator and the load.

14. The wireless power system of claim 13, wherein the portable electronic device is a cell phone, a computer, or a robot.

15. The wireless power system of claim 12, wherein the device resonator is configured to be movable relative to the source resonator over the range of distances D between the source resonator and the device resonator.

16. The wireless power system of claim 12, wherein the power provided to the load from the device resonator defines a work drainage rate Γ

_w, and wherein the work drainage rate Γ

_w is configured to be set such that Γ

_w=Γ

₂√

{square root over (1+(κ

²/Γ

₁·

Γ

₂))} for some value of the coupling coefficient κ

in the range of distances D.

17. The wireless power system of claim 16, wherein the conducting loop in each of the source resonator and the device resonator is capacitively loaded.

18. The wireless power system of claim 12, wherein the power provided to the load from the device resonator defines a work drainage rate Γ

_w, and wherein the work drainage rate Γ

_w is configured to be set such that the ratio of useful-to-lost power is maximized for some value of the-coupling coefficient κ

in the range of distances D.

19. The wireless power system of claim 18, wherein the work drainage rate Γ

_w is configured to be set such that Γ

_w=Γ

₂√

{square root over (1+(κ

²/Γ

₁·

Γ

₂))} for said value of the coupling coefficient κ

in the range of distances D.

20. The wireless power system of claim 12, wherein the power provided to the load from the device resonator defines a work drainage rate Γ

_w, and wherein the work drainage rate Γ

_w is configured to be set such that Γ

_w>

Γ

₂.

21. The wireless power system of claim 12, wherein each resonator comprises at least one loop of conductive material.

22. A method for providing wireless power to a load, the method comprising:

providing a source resonator and a power supply coupled to the source resonator to provide power to the source resonator, the source resonator having a resonant frequency ω

₁, an intrinsic loss rate Γ

₁, and an intrinsic quality factor Q₁=ω

₁/(2Γ

₁); and

providing a device resonator coupled to the load to provide power to the load, the device resonator having a resonant frequency ω

₂, an intrinsic loss rate Γ

₂, and an intrinsic quality factor Q₂=ω

₂/(2Γ

₂),

resonantly and wirelessly coupling electromagnetic power from the source resonator to the device resonator using non-radiative electromagnetic induction having a coupling coefficient κ

, and wherein the intrinsic loss rates satisfy κ

/Γ

₁Γ

₂>

5 over a range of distances D between the source resonator and the device resonator,

wherein Q₁>

200 and Q₂>

200.

23. The method of claim 22, wherein the load is configured to provide power to a vehicle.

24. A method for providing wireless power to a load, the method comprising:

providing a source resonator and a power supply coupled to the source resonator to provide power to the source resonator, the source resonator having a resonant frequency ω

₁, an intrinsic loss rate Γ

₁, and an intrinsic quality factor Q₁=ω

₁/(2Γ

₁); and

providing a device resonator coupled to the load to provide power to the load, the device resonator having a resonant frequency ω

₂, an intrinsic loss rate Γ

₂, and an intrinsic quality factor Q₂=ω

₂/(2Γ

₂),

resonantly and wirelessly coupling electromagnetic power from the source resonator to the device resonator using non-radiative electromagnetic induction having a coupling coefficient κ

, and wherein the intrinsic loss rates satisfy κ

/√

{square root over (Γ

₁Γ

₂)}>

1 over a range of distances D between the source resonator and the device resonator,

wherein Q₁>

100 and Q₂>

100, and

wherein f₁=ω

₁/(2π

) and f₂=ω

₂/(2π

), and f₁ and f₂, are between 1 MHz and 10 MHz, and wherein each intrinsic loss rate comprises a resistive component and a radiative component.

25. The method of claim 24, wherein the device resonator and the load are part of a portable electronic device, and wherein the portable electronic device is a cell phone, a computer, or a robot.