WIRELESS ENERGY TRANSFER ACROSS VARIABLE DISTANCES

• US 20100102641A1
• Filed: 12/30/2009
• Published: 04/29/2010
• 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 D.
• Granted Patent: US 8,400,024 B2
• Time in Patent Office: Days
• US Class Current: 307/104
• 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

Described herein are embodiments of transferring electromagnetic energy that includes a first electromagnetic resonator receiving energy from an external power supply, said first resonator having a resonant frequency ω₁, an intrinsic loss rate Γ₁, and a first Q-factor Q₁=ω₁L₁/(R_1ohm+R_1rad), generating an oscillating near field region, a second electromagnetic resonator being positioned at variable distances from said first resonator and not electrically wired to said first resonator, said second resonator having a resonant frequency ω₂, an intrinsic loss rate Γ₂, and a second Q-factor Q₂=ω₂L₂/(R_2ohm+R_2rad). Electromagnetic energy may be transferred from said first resonator to said second resonator over a variable distance D that may be within the near-field region of the first resonator structure, and wherein R_1ohm>R_1rad, and R_2ohm>R_2rad.

Claims

1. A method of transferring electromagnetic energy comprising:

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

₁, an intrinsic loss rate Γ

₁, and a first Q-factor Q₁=ω

₁L₁/(R_1ohm+R_1rad), generating an oscillating near field region;

providing a second electromagnetic resonator being positioned at variable distances from said first resonator and not electrically wired to said first resonator, said second resonator having a resonant frequency ω

₂, an intrinsic loss rate Γ

₂, and a second Q-factor Q₂=ω

₂L₂/(R_2ohm+R_2rad); and

transferring electromagnetic energy from said first resonator to said second resonator over a variable distance D that is within the near-field region of the first resonator structure, and

wherein R_1ohm>

R_1rad, and R_2ohm>

R_2rad.

2. The method of claim 1 wherein the distance between the resonators is greater than 5 cm.

3. The method of claim 1 wherein the distance between the resonators is greater than 10 cm.

4. The method of claim 1 wherein that distance between the resonators is larger than the characteristic size of the smaller of the first resonator and the second resonator.

5. The method of claim 1, wherein each resonator comprises an electrical conductor shaped into one or more loops wound in substantially a single plane circumscribing a substantially planar area.

6. The method of claim 5, wherein the loops of the electrical conductors of each of the first and second resonators are in substantially the same plane.

7. The method of claim 5 wherein a line drawn from the center of the first resonator to the center of the second resonator is substantially normal to the circumscribed planar area of each resonator.

8. The method of claim 5 wherein a line drawn from the center of the first resonator to the center of the second resonator is substantially parallel to the circumscribed planar area of each resonator.

9. The method of claim 5 wherein a line drawn from the center of the first resonator to the center of the second resonator forms a different angle to the surface area circumscribed by the first resonator than to the circumscribed planar area of each resonator.

10. The method of claim 1 wherein at least one of the resonators has a quality factor, Q, greater than 100.

11. A system of transferring electromagnetic energy comprising:

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

₁, an intrinsic loss rate Γ

₁, and a first Q-factor Q₁=ω

₁L₁/(R_1ohm+R_1rad), generating an oscillating near field region;

a second electromagnetic resonator being positioned at variable distances from said first resonator and not electrically wired to said first resonator, said second resonator having a resonant frequency ω

₂, an intrinsic loss rate Γ

₂, and a second Q-factor Q₂=ω

₂L₂/(R_2ohm+R_2rad),

wherein electromagnetic energy is transferred from said first resonator to said second resonator over a variable distance D that is within the near-field region of the first resonator structure, and

wherein R_1ohm>

R_1rad, and R_2ohm>

R_2rad.

12. The system of claim 11, wherein the distance between the resonators is greater than 5 cm.

13. The system of claim 11, wherein the distance between the resonators is greater than 10 cm.

14. The system of claim 11, wherein that distance between the resonators is larger than the characteristic size of the smaller of the first resonator and the second resonator.

15. The system of claim 11, wherein each resonator comprises an electrical conductor shaped into one or more loops wound in substantially a single plane circumscribing a substantially planar area.

16. The system of claim 15, wherein the loops of the electrical conductors of each of the first and second resonators are in substantially the same plane.

17. The system of claim 15, wherein a line drawn from the center of the first resonator to the center of the second resonator is substantially normal to the circumscribed planar area of each resonator.

18. The system of claim 15, wherein a line drawn from the center of the first resonator to the center of the second resonator is substantially parallel to the circumscribed planar area of each resonator.

19. The system of claim 15, wherein a line drawn from the center of the first resonator to the center of the second resonator forms a different angle to the surface area circumscribed by the first resonator than to the circumscribed planar area of each resonator.

20. The system of claim 11, wherein at least one of the resonators has a quality factor, Q, greater than 100.