Wireless non-radiative energy transfer
AssigneeMassachusetts Institute of Technology
InventorsJohn D. Joannopoulos, Aristeidis Karalis, Marin Soljacic
Life of this patent
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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.
Claims69
A system for wirelessly providing power to a load, the system comprising:
- a first electromagnetic resonator configured to be coupled to a power supply, the first resonator having a characteristic size L1, a resonant frequency ω1, an intrinsic loss rate Γ1, and a first Q-factor Q1=ω1/(2Γ1);
- a second electromagnetic resonator configured to be coupled to the load, the second resonator having a characteristic size L2, a resonant frequency ω2, an intrinsic loss rate Γ2, and a second Q-factor Q2=ω2/(2Γ2),
- wherein the first and second resonators are configured to be wirelessly coupled to provide resonant non-radiative wireless power to the second resonator from the first resonator with a wireless energy transfer rate κ, and
- wherein the resonators satisfy κ/√{square root over (Γ1Γ2)}>1 for at least some distances D between the first and second resonators satisfying D/L2>1.
A system for wirelessly providing power to a portable electronic device, the system comprising:
- a first electromagnetic resonator coupled to a power supply, the first resonator having a resonant frequency ω1, an intrinsic loss rate Γ1, and a first Q-factor Q1=ω1/(2Γ1);
- a second electromagnetic resonator coupled to a load in the portable electronic device, the second resonator having a resonant frequency ω2, an intrinsic loss rate Γ2, and a second Q-factor Q2=ω2/(2Γ2),
- wherein the first and second resonators are wirelessly coupled to provide resonant non-radiative wireless power to the second resonator from the first resonator with a wireless energy transfer rate κ and an efficiency of at least 20% for distances D of at least 10 cm between the first and second resonators.
A portable electronic device for use with a first electromagnetic resonator coupled to a power supply, the first resonator having a characteristic size L1, a resonant frequency ω1, an intrinsic loss rate Γ1, and a first Q-factor Q1=ω1/(2Γ1), the portable electronic device comprising:
- a load;
- and
- a second electromagnetic resonator configured to be coupled to the load and movable relative to the first resonator, the second resonator having a characteristic size L2, a resonant frequency ω2, an intrinsic loss rate Γ2, and a second Q-factor Q2=ω2/(2Γ2),
- wherein the second resonator is configured to be wirelessly coupled to the first resonator to provide resonant non-radiative wireless power to the second resonator from the first resonator with a wireless energy transfer rate κ, and
- wherein the resonators satisfy κ/√{square root over (Γ1Γ2)}>1 for at least some distances D between the first and second resonators satisfying D/L2>1.
A power source for wirelessly providing power to a portable electronic device, the power source comprising:
- a power supply;
- and
- a first electromagnetic resonator coupled to a power supply, the first resonator having a characteristic size L1, a resonant frequency ω1, an intrinsic loss rate Γ1, and a first Q-factor Q1=ω1/(2Γ1), the portable electronic device,
- wherein the first resonator is configured to be wirelessly coupled to a second electromagnetic resonator in the portable electronic device to provide non-radiative wireless power to the second resonator from the first resonator with a wireless energy transfer rate κ,
- wherein the second electromagnetic resonator is coupled to a load in the portable electronic device and movable relative to the first resonator, the second resonator having a characteristic size L2, a resonant frequency ω2, an intrinsic loss rate Γ2, and a second Q-factor Q2=ω2/(2Γ2),
- wherein the resonators satisfy κ/√{square root over (Γ1Γ2)}>1 for at least some distances D between the first and second resonators satisfying D/L2>1.
A portable electronic device for use with a first electromagnetic resonator coupled to a power supply, the first resonator having a resonant frequency ω1, an intrinsic loss rate Γ1, and a first Q-factor Q1=ω1/(2Γ1), the portable electronic device comprising:
- a load;
- and
- a second electromagnetic resonator configured to be coupled to the load and movable relative to the first resonator, the second resonator having a resonant frequency ω2, an intrinsic loss rate Γ2, and a second Q-factor Q2=ω2/(2Γ2),
- wherein the second resonator is configured to be wirelessly coupled to the first resonator to provide resonant non-radiative wireless power to the second resonator from the first resonator with a wireless energy transfer rate κ, and
- wherein the efficiency of the wireless power transfer is at least 20% for distances D of at least 10 cm between the first and second resonators.
A power source for wirelessly providing power to a portable electronic device, the power source comprising:
- a power supply;
- and
- a first electromagnetic resonator coupled to a power supply, the first resonator having a resonant frequency ω1, an intrinsic loss rate Γ1, and a first Q-factor Q1=ω1/(2Γ1), the portable electronic device,
- wherein the first resonator is configured to be wirelessly coupled to a second electromagnetic resonator in the portable electronic device to provide non-radiative wireless power to the second resonator from the first resonator with a wireless energy transfer rate κ,
- wherein the second electromagnetic resonator is coupled to a load in the portable electronic device and movable relative to the first resonator, the second resonator having a resonant frequency ω2, an intrinsic loss rate Γ2, and a second Q-factor Q2=ω2/(2Γ2),
- wherein the efficiency of the wireless power transfer is at least 20% for distances D of at least 10 cm between the first and second resonators.
Dependencies are inferred from the claim text.