WIRELESS POWER TRANSFER USING MULTIPLE NEAR-FIELD PLATES

• US 20160087458A1
• Filed: 12/03/2015
• Published: 03/24/2016
• Est. Priority Date: 04/16/2014
• Status: Active Grant

• Current Assignee: Board of Regents of the University of Michigan (University of Michigan)
• Original Assignee: Board of Regents of the University of Michigan (University of Michigan)
• Inventors: Grbic, Anthony, Young, Steve
• Granted Patent: US 9,793,720 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B60L 53/122 Circuits or methods for driving the primary coil, e.g. supplying electric power to the coil
• CPC Class Codes: H01F 2038/146 in combination with capacitive coupling
• 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: 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

A near-field plate is a non-periodically patterned surface that can overcome the diffraction limit and confine electromagnetic fields to subwavelength dimensions. By controlling the interference of the electromagnetic fields radiated by the near-field plate with that of a source, the near-field plate can form a subwavelength near-field pattern in a forward direction, while suppressing fields in other directions, such as those reflected. The resulting unidirectional near-field plate may find utility in many applications such as high resolution imaging and probing, high density data storage, biomedical targeting devices, and wireless power transfer.

Claims

1. A method for wireless transfer of power from a transmitting side to a receiving side, the method comprising:

generating a source field pattern energy from an excitation power source at a focal plane of the transmitting side;

generating a subwavelength field pattern of energy from a transmitting side near-field plate when the near-field plate is excited by the excitation source, the transmitter side near-field plate being at a distance, d, from the excitation source;

receiving energy at the receiving side in a desired field pattern received by a receiving side near-field plate positioned to excite a power receiver, where the desired field pattern is formed at a focal plane of the receiving side and from the subwavelength field pattern and the source field pattern, the focal plane of the receiving side being at a distance, L, from the excitation source, and wherein the receiving side near-field plate is positioned at the focal plane of the receiving side; and

converting the received energy into a received power, at a power conversion efficiency.

2. The method of claim 1, further comprising:

increasing the amplitude of the desired field pattern by varying an amplification factor at the transmitting side.

3. The method of claim 1, further comprising:

increasing the power conversion efficiency at the receiving side by varying a distance between the receiving side near-field plate the power receiver.

4. The method of claim 1, wherein the excitation power source is a transmitting loop and wherein the power receiver is a receiving loop.

5. The method of claim 4, wherein the transmitting side near-field plate has the same configuration as the receiving side near field plate.

6. The method of claim 4, wherein the transmitting side near-field plate has a different configuration than the receiving side near field plate.

7. The method of claim 4, wherein the transmitting side near-field plate is formed of a plurality of concentric loops.

8. The method of claim 4, wherein the receiving side near-field plate is formed of a plurality of concentric loops.

9. The method of claim 4, wherein the transmitting loop comprises a multi-turn coil;

and the receiving loop comprises a multi-turn coil.

10. The method of claim 1, further comprising:

supplying the received power to a device for wirelessly power the device or wirelessly charging the device, wherein the device includes one or more of a computer, a smartphone, a biometric sensor device, a chargeable battery, or a vehicle using a chargeable battery.

11. An apparatus for wireless power transfer from a transmitting side to a receiving side, the apparatus comprising:

an excitation power source generating a source field pattern energy at the transmitting side;

a transmitting side near-field plate generating a subwavelength field pattern energy when excited by the excitation source, wherein after traversing a near-field distance, L, the source field pattern energy and the subwavelength field pattern energy form a desired field pattern energy at a focal plane, wherein the desired field pattern energy has a unidirectional subwavelength field pattern when the amplitude of the subwavelength field pattern is increased; and

a power receiver and a receiving side near-field plate at the receiving side, the receiving side near-field plate being positioned at the focal plane and spaced a distance from the power receiver to couple a received energy from desired field pattern energy to the power receiver, wherein the power receiver is configured to convert the received energy into a received power for provision to a load.

12. The apparatus of claim 11, wherein the excitation power source is a transmitting loop and wherein the power receiver is a receiving loop.

13. The apparatus of claim 12, wherein the transmitting side near-field plate has the same configuration as the receiving side near field plate.

14. The apparatus of claim 12, wherein the transmitting side near-field plate has a different configuration than the receiving side near field plate.

15. The apparatus of claim 12, wherein the transmitting side near-field plate is formed of a plurality of concentric loops.

16. The apparatus of claim 12, wherein the receiving side near-field plate is formed of a plurality of concentric loops.

17. The apparatus of claim 12, wherein the transmitting loop comprises a Wü

rth coil; and

the receiving loop comprises a Wü

rth coil.

18. The apparatus of claim 12, further wherein the load is a device to receive the received power for wirelessly powering the device or wirelessly charging the device, wherein the device includes one or more of a computer, a smartphone, a biometric sensor device, a chargeable battery, or a vehicle using a chargeable battery.