Wireless energy transfer in lossy environments

Patent metadata

Field	Value
Publication number	US-9515495-B2
Application number	US-201514927740-A
Country	US
Kind code	B2
Filing date	Oct 30, 2015
Priority date	Sep 27, 2008
Publication date	Dec 6, 2016
Grant date	Dec 6, 2016

Abstract

Described herein are improved configurations for a wireless power transfer for electronic devices that include at least one source magnetic resonator including a capacitively-loaded conducting loop coupled to a power source and configured to generate an oscillating magnetic field and at least one device magnetic resonator, distal from said source resonators, comprising a capacitively-loaded conducting loop configured to convert said oscillating magnetic fields into electrical energy, wherein at least one said resonator has a keep-out zone around the resonator that surrounds the resonator with a layer of non-lossy material.

First claim

What is claimed is:

1. A wirelessly chargeable mobile electronic device, comprising:
a device magnetic resonator comprising a capacitively-loaded conducting loop configured to receive an oscillating magnetic field from a source magnetic resonator, wherein the device magnetic resonator has an unperturbed device quality factor Q D ; and
material positioned to space lossy material from at least a portion of the conducting loop and thereby form a keep-out zone,
wherein the keep-out zone enables the device magnetic resonator to have a perturbed device quality factor, Q D,perturbed , that is at least 50% of the unperturbed device quality factor Q D when the lossy material is positioned immediately outside the keep-out zone.

2. The device of claim 1 , wherein the keep-out zone extends for a distance of more than 0.25 mm outward from the device magnetic resonator.

3. The device of claim 1 , wherein a maximum dimension of the keep-out zone is approximately 1.0% greater than a characteristic size of the device magnetic resonator.

4. The device of claim 1 , wherein a maximum dimension of the keep-out zone is approximately 0.1% greater than a characteristic size of the device magnetic resonator.

5. The device of claim 1 , wherein the device magnetic resonator further comprises a magnetic material.

6. The device of claim 1 , wherein the unperturbed device quality factor Q D is greater than 100.

7. The device of claim 1 , further comprising device power and control circuitry coupled to the device magnetic resonator, wherein the keep-out zone extends beyond at least one surface of the device power and control circuitry.

8. The device of claim 1 , wherein the material forming the keep-out zone is a layer of material positioned to cover at least one side of the conducting loop.

9. The device of claim 8 , wherein the capacitively-loaded conducting loop of the device magnetic resonator is built on a printed circuit board (PCB).

10. The device of claim 9 , wherein the layer of material forming the keep-out zone and the printed circuit board are on opposite sides of the capacitively-loaded conducting loop.

11. The device of claim 8 , wherein the material forming the keep-out zone is insulation material on the conducting loop.

12. The device of claim 1 , wherein the lossy material has a non-zero, but finite conductivity.

13. The device of claim 1 , wherein the perturbed source quality factor, Q S,perturbed is at least 50% of the unperturbed source quality factor Q D when the lossy material spans the outside of the keep-out zone.

14. The device of claim 13 , wherein the perturbed device quality factor, Q D,perturbed is at least 50% of the unperturbed device quality factor Q D when the lossy material spans the outside of the keep-out zone and the lossy material has a resistivity of 0.2 ohms·meters at the frequency of the oscillating magnetic field.

15. The device of claim 1 , wherein the keep-out zone extends from the conducing loop by less than 1 cm.

16. The device of claim 1 , further comprising packaging for the device magnetic resonator, and wherein the material forming the keep-out zone is part of the packaging.

17. The device of claim 1 , wherein the material forming the keep-out zone comprises plastics, composites, plastic composites, Teflon, Rexolite, ABS, or ceramics.

18. The device of claim 1 , wherein the unperturbed device quality factor Q D corresponds to the intrinsic quality factor of the device resonator.

19. A method of making a module for use in a wireless power system, the method comprising:
providing a magnetic resonator formed by a capacitively-loaded conducting loop built on a printed circuit board, wherein the magnetic resonator has an intrinsic quality factor Q greater than 100; and
forming a keep-out zone in the module by positioning a layer of insulating material to cover the capacitively-loaded conducting loop and space lossy material from the conducting loop,
wherein the keep-out zone extends from the conducting loop by less than 1 cm and enables the magnetic resonator to have a perturbed quality factor, Q perturbed , that is at least 50% of the intrinsic quality factor Q when the lossy material is positioned immediately outside the keep-out zone and covers the keep-out zone.

20. The method of claim 19 , wherein the perturbed quality factor, Q perturbed , is at least 50% of the intrinsic quality factor Q when the lossy material is positioned immediately outside the keep-out zone, covers the keep-out zone, and has a resistivity of 0.2 ohms meters at the resonant frequency of the magnetic resonator.

Assignees

• Witricity Corp

Inventors

• Kurs Andre B
• Hall Katherine L
• Kesler Morris P
• Soljacic Marin
• Giler Eric R

Classifications

• H01F38/14 Primary

  Inductive couplings {(for wireless supply or distribution of electric power using inductive coupling H02J50/10)} · CPC title

• H02J7/82

  Control of state of charge [SOC] · CPC title

• H02J7/62

  against overcurrent · CPC title

• H03H7/40

  Automatic matching of load impedance to source impedance · CPC title

• B60L2200/26

  Rail vehicles · CPC title