Wireless non-radiative energy transfer

• US 20070222542A1
• Filed: 07/05/2006
• Published: 09/27/2007
• Est. Priority Date: 07/12/2005
• Status: Active Grant

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Karalis, Aristeidis, Soljacic, Marin, Joannopoulos, John
• Granted Patent: US 7,741,734 B2
• Time in Patent Office: Days
• US Class Current: 333/219
• 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 5/0037 for power transfer
• 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

The electromagnetic energy transfer device includes a first resonator structure receiving energy from an external power supply. The first resonator structure has a first Q-factor. A second resonator structure is positioned distal from the first resonator structure, and supplies useful working power to an external load. The second resonator structure has a second Q-factor. The distance between the two resonators can be larger than the characteristic size of each resonator. Non-radiative energy transfer between the first resonator structure and the second resonator structure is mediated through coupling of their resonant-field evanescent tails.

Claims

1. A method of transferring energy comprising:

providing a first resonator structure receiving energy from an external power supply, said first resonator structure having a first resonant frequency ω

₁, and a first Q-factor Q₁, and characteristic size L₁, and

providing a second resonator structure being positioned distal from said first resonator structure, at closest distance D, said second resonator structure having a second resonant frequency ω

₂, and a second Q-factor Q₂, and characteristic size L₂

wherein the two said frequencies ω

₁ and ω

₂ are close to within the narrower of the two resonance widths r₁, and r₂,

transferring energy non-radiatively between said first resonator structure and said second resonator structure, said energy transfer being mediated through coupling of their resonant-field evanescent tails, and the rate of energy transfer between said first resonator and said second resonator being denoted by κ

,

wherein non-radiative means D is smaller than each of the resonant wavelengths λ

₁ and λ

₂, wherein c is the propagation speed of radiation in the surrounding medium.

2. The method of claim 1, wherein said method comprising said resonators with Q₁>

100, and Q₂>

100, and κ

/sqrt(Γ

₁*Γ

₂)>

0.2, 0.5, 1, 2, 5, and D/L₂>

1, 2, 3, 5.

3. The method of claim 1, wherein said method comprising said resonators with Q₁>

200, and Q₂>

200, and κ

/sqrt(Γ

₁*Γ

₂)>

0.2, 0.5, 1, 2, 5, and D/L₂>

1, 2, 3, 5.

4. The method of claim 1, said method comprising said resonators with Q₁>

500, and Q₂>

500, and κ

/sqrt(Γ

₁*Γ

₂)>

0.2, 0.5, 1, 2, 5, and D/L₂>

1, 2, 3, 5.

5. The method of claim 1, said method comprising said resonators with Q₁>

1000, and Q₂>

1000, and κ

/sqrt(Γ

₁*Γ

₂)>

0.2, 0.5, 1, 2, 5, and D/L₂>

1, 2, 3, 5.

6. An energy transfer device comprising:

a first resonator structure receiving energy from an external power supply, said first resonator structure having a first resonant frequency ω

₁, and a first Q-factor Q₁, and characteristic size L₁, and

a second resonator structure being positioned distal from said first resonator structure, at closest distance D, said second resonator structure having a second resonant frequency ω

₂, and a second Q-factor Q₂, and characteristic size L₂,

wherein the two said frequencies ω

₁ and ω

₂ are close to within the narrower of the two resonance widths Γ

₁, and Γ

₂,

wherein non-radiative energy transfer between said first resonator structure and said second resonator structure is mediated through coupling of their resonant-field evanescent tails, and the rate of energy transfer between said first resonator and said second resonator is denoted by κ

,

wherein non-radiative means D is smaller than each of the resonant wavelengths λ

₁ and λ

₂, wherein c is the propagation speed of radiation in the surrounding medium.

7. The energy transfer device of claim 6, said method comprising said resonators with Q₁>

200, and Q₂>

200, and κ

/sqrt(Γ

₁*Γ

₂)>

0.2, 0.5, 1, 2, 5, and D/L₂>

1, 2, 3, 5.

8. The energy transfer device of claim 7, wherein said resonant field in said device is electromagnetic.

9. The energy transfer device of claim 8 and said first resonator structure comprises a dielectric sphere, where the characteristic size L₁ is the radius of the sphere.

10. The energy transfer device of claim 8, and said first resonator structure comprises a metallic sphere, where the characteristic size L₁ is the radius of the sphere.

11. The energy transfer device of claim 8, and said first resonator structure comprises a metallodielectric sphere, where the characteristic size L₁ is the radius of the sphere.

12. The energy transfer device of claim 8, and said first resonator structure comprises a plasmonic sphere, where the characteristic size L₁ is the radius of the sphere.

13. The energy transfer device of claim 8, and said first resonator structure comprises a polaritonic sphere, where the characteristic size L₁ is the radius of the sphere.

14. The energy transfer device of claim 8, and said first resonator structure comprises a capacitively-loaded conducting-wire loop, where the characteristic size L₁ is the radius of the loop.

15. The energy transfer device of claim 8, and said second resonator structure comprises a dielectric sphere, where the characteristic size L₂ is the radius of the sphere.

16. The energy transfer device of claim 8, and said second resonator structure comprises a metallic sphere where the characteristic size L₂ is the radius of the sphere.

17. The energy transfer device of claim 8, and said second resonator structure comprises a metallodielectric sphere where the characteristic size L₂ is the radius of the sphere.

18. The energy transfer device of claim 8, and said second resonator structure comprises a plasmonic sphere where the characteristic size L₂ is the radius of the sphere.

19. The energy transfer device of claim 8, and said second resonator structure comprises a polaritonic sphere where the characteristic size L₂ is the radius of the sphere.

20. The energy transfer device of claim 8, and said second resonator structure comprises a capacitively-loaded conducting-wire loop where the characteristic size L₂ is the radius of the loop.

21. The energy transfer device of claim 7, wherein said resonant field in said device is acoustic.