Magnetic resonance coupling arrangement

• US 10,044,227 B2
• Filed: 06/02/2015
• Issued: 08/07/2018
• Est. Priority Date: 06/02/2014
• Status: Active Grant

• Current Assignee: Purdue Research Foundation (The Trustees of Purdue University (d/b/a Purdue University))
• Original Assignee: Purdue Research Foundation (The Trustees of Purdue University (d/b/a Purdue University))
• Inventors: Chappell, William J., Ha, Dohyuk, Mei, Henry, Irazoqui, Pedro P.
• Primary Examiner(s): Fureman, Jared
• Assistant Examiner(s): Htun, Win
• Application Number:
  US14/728,976
• Publication Number:
  US 20150380988A1
• Time in Patent Office: 1,162 Days
• Field of Search: 307104
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/50 using additional energy repeaters between transmitting devices and receiving devices

Abstract

A wireless power transfer system is disclosed. The system includes a first resonator having a first resonant frequency ω_o1, a half power bandwidth Δω₁, and an unloaded quality factor Qo₁=ω_o1/Δω₁ coupled through a first coupling circuit to a power source, a second resonator having a second resonant frequency ω_o2, a half power bandwidth Δω₂, and an unloaded quality factor Qo₂=ω_o2/Δω₂ coupled through a second coupling circuit to a load, the first resonator disposed a distance away from the second resonator, wherein the distance is smaller than the first and second resonant wavelengths, the first and second coupling circuits are configured so that up to a maximum achievable power transfer efficiency between the first and second resonators can be achieved, wherein Qo₁ and Qo₂ can be less than 100.

Claims

1. A wireless power transfer system, comprising:

a first resonator having a first resonant frequency ω

_o1, a half power bandwidth Δ

ω

₁, and an unloaded quality factor Qo₁=ω

_o1/Δ

ω

₁ coupled through a first coupling circuit to a power source; and

a second resonator having a second resonant frequency ω

_o2, a half power bandwidth Δ

ω

₂, and an unloaded quality factor Qo₂=ω

_o2/Δ

ω

₂ coupled through a second coupling circuit to a load, the first resonator disposed a distance away from the second resonator, wherein the distance is smaller than the first and second resonant wavelengths;

the first and second coupling circuits configured so that up to a maximum achievable power transfer efficiency between the first and second resonators can be achieved, wherein Qo₁ and Qo₂ can be less than 100, wherein the configuring of the first and second coupling circuits based on expressing transmission power from the first resonator to the second resonator as a function of external coupling with the source and external coupling with the load and determining partial derivatives of the transmission power with respect to the external couplings in order to find optimal external couplings and in order to find optimal characteristic impedance of the first and second coupling circuits,

wherein the partial derivatives of the transmission power with respect to the external couplings are governed by;

2. The wireless power transfer system of claim 1, optimal characteristic impedance of the first and second coupling circuits are used to find lumped parameter values for components of the first and second coupling circuits.

3. The wireless power transfer system of claim 1, the lumped parameter values for components of the first and second coupling circuits are governed by:

4. The wireless power transfer system of claim 1, the first and second coupling circuits are re-configured to continue to provide a maximum power transfer efficiency between the first and second resonators as the distance between the first and second resonators change.

8. The wireless power transfer system of claim 1, the first and second coupling circuits are re-configured to continue to provide a maximum power transfer efficiency between the first and second resonators as the distance between the first and second resonators change.

5. A method of providing a maximum wireless power transfer efficiency between a first resonator and a second resonator, comprising:

providing a first resonator having a first resonant frequency ω

_o1, a half power bandwidth Δ

ω

₁, and an unloaded quality factor Qo₁=ω

_o1/Δ

ω

₁ coupled through a first coupling circuit to a power source;

providing a second resonator having a second resonant frequency ω

_o2, a half power bandwidth Δ

ω

₂, and an unloaded quality factor Qo₂=ω

_o2/Δ

ω

₂ coupled through a second coupling circuit to a load, the first resonator disposed a distance away from the second resonator, wherein the distance is smaller than the first and second resonant wavelengths;

configuring the first and second coupling circuits so that up to a maximum power transfer efficiency between the first and second resonators can be achieved, wherein Qo₁ and Qo₂ can be less than 100, wherein the configuring of the first and second coupling circuits based on expressing transmission power from the first resonator to the second resonator as a function of external coupling with the source and external coupling with the load and determining partial derivatives of the transmission power with respect to the external couplings in order to find optimal external couplings in order to find optimal characteristic impedance of the first and second coupling circuits,

wherein the partial derivatives of the transmission power with respect to the external couplings are governed by;

6. The wireless power transfer system of claim 5, finding optimal characteristic impedance of the first and second coupling circuits are used to find lumped parameter values for components of the first and second coupling circuits.

7. The wireless power transfer system of claim 5, the lumped parameter values for components of the first and second coupling circuits are governed by: