Method and apparatus for wireless power transmission

• US 9,129,741 B2
• Filed: 09/14/2007
• Issued: 09/08/2015
• Est. Priority Date: 09/14/2006
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Tseng, Ryan
• Primary Examiner(s): Chan, Tsz
• Application Number:
  US11/901,158
• Publication Number:
  US 20080067874A1
• Time in Patent Office: 2,916 Days
• Field of Search: 336/200, 336/232
• US Class Current: 1/1
• CPC Class Codes: A61C 17/224 Electrical recharging arrangements
• CPC Class Codes: H01F 17/0006 Printed inductances printed coils for dynamo-electric machines H02K3/26; printed circuits H05K
• 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 50/10 using inductive coupling
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/402 the two or more transmitting or the two or more receiving devices being integrated in the same unit, e.g. power mats with several coils or antennas with several sub-antennas
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H02J 7/0042 characterised by the mechanical construction

Abstract

Embodiments of the invention relate to a method and system for transferring power wirelessly to electronic devices. The system can utilize magnetic coupling between two coils at close proximity to transfer sufficient power to charge an electronic device. Embodiments of the invention pertain to an array of spiral coils that can be used to transmit power for transfer to receiver coils. Potential applications of this technology include charging consumer electronic devices (cell phones, laptops, PDAs, etc), developing hermetically sealed devices for extreme environments, and less invasive transcutaneous energy transfer (TET) systems. Various embodiments of the subject system can be referred to as PowerPad system. Embodiments can incorporate one or more of the following: planar inductors, PCB transformers, and very high frequency power supplies. Embodiments of the invention also pertain to planar inductors having characteristics that allow the production of even magnetic field, as well as systems that incorporate such planar inductors.

Claims

1. A coil configured to generate a wireless field, the coil comprising:

a planar spiral inductor the planar spiral inductor located in a plane and having a conductive trace having an increasing width which does not decrease from an outer periphery of the planar spiral inductor to the center of a spiral formed by the planar spiral inductor.

2. The coil according to claim 1, further comprising:

at least one additional planar spiral inductor, wherein the width of each of the at least one additional planar spiral inductor'"'"'s trace becomes wider as the trace spirals toward the center of a spiral formed by the at least one additional planar spiral inductor, and wherein the widening of each trace as the trace spirals toward the center of the spiral formed by the at least one additional planar spiral inductor produces a more even magnetic field distribution.

3. The coil according to claim 2, wherein the planar spiral inductor and the at least one additional planar spiral inductor form an array of planar spiral inductors, the array of planar spiral inductors being positioned parallel to a surface, and wherein the array of planar spiral inductors is configured to produce a wireless field extending beyond the surface.

4. The coil according to claim 1, wherein the planar spiral inductor has a square shape.

5. The coil according to claim 1, wherein the trace becomes thicker as the trace spirals toward the center of the spiral formed by the planar spiral inductor.

6. The coil according to claim 4, wherein the square shaped planar spiral inductor has smoothed corners configured to reduce a current crowding effect.

7. The coil of claim 1, wherein the coil comprises an RF coil.

8. A system for providing power to a device, the system comprising:

a base station, the base station comprising a planar spiral inductor forming a spiral, the planar spiral inductor located in a plane and having a conductive trace having an increasing width which does not decrease from an outer periphery of the planar spiral inductor to the center of the spiral formed by the planar spiral inductor;

a power supply configured to drive the planar spiral inductor to generate a wireless field having a charging region; and

a device including a receiver, the receiver configured to receive power via the wireless field when the receiver is positioned within the charging region of the planar spiral inductor and to provide power to the device based on the received power.

9. The system according to claim 8, wherein the base station further comprises:

at least one additional planar spiral inductor, wherein the width of each of the at least one additional planar spiral inductor'"'"'s trace becomes wider as the trace spirals toward the center of a spiral formed by the at least one additional planar spiral inductor, and wherein the widening of each trace as the trace spirals toward the center of the spiral formed by the at least one additional planar spiral inductor produces a more even magnetic field distribution.

10. The system according to claim 9, wherein the planar spiral inductor and the at least one additional planar spiral inductor form an array of planar spiral inductors, wherein the array of planar spiral inductors are positioned parallel to a surface.

11. The system according to claim 10, wherein the array of planar spiral inductors are separated into two or more separate regions, and wherein each separate region is configured to be activated only when a receiver is located in the charging region of the separate region.

12. The system according to claim 10, further comprising:

a sensing mechanism configured to identify a load impedance of devices located in the charging region of the array of planar spiral inductors; and

a microcontroller configured to adjust the power supply to increase the efficiency of power transfer from the array of planar spiral inductors to the devices located in the charging region of the array of planar spiral inductors.

13. The system according to claim 10, further comprising:

a plurality of sensors, wherein the plurality of sensors are configured to detect the impedance mismatch between the array of planar spiral inductors and devices located in the charging region of the array of planar spiral inductors; and

an adaptive impedance matching network, wherein the adaptive impedance matching network tunes the array of planar spiral inductors to resonate based on the impedance mismatch detected by the sensors.

14. The system according to claim 10, wherein the thickness of each planar spiral inductor of the array of planar spiral inductors is greater than two times the skin depth of the planar spiral inductor.

15. A method of providing power to a device including a receiver, the method comprising:

generating a wireless field, the wireless field having a charging region, the wireless field generated via a planar spiral inductor forming a spiral, the planar spiral inductor located in a plane and having a conductive trace having an increasing width which does not decrease from an outer periphery of the planar spiral inductor to the center of the spiral formed by the planar spiral inductor;

transmitting power via the wireless field to a receiver located within the charging region, the receiver configured to provide power to the device.

16. The method according to claim 15, wherein the wireless field is generated via at least one additional planar spiral inductor, wherein the width of each of the at least one additional planar spiral inductor'"'"'s trace becomes wider as the trace spirals toward the center of a spiral formed by the at least one additional planar spiral inductor, and wherein the widening of each trace as the trace spirals toward the center of the spiral formed by the at least one additional planar spiral inductor produces a more even magnetic field distribution.

17. The method according to claim 16, wherein the planar spiral inductor and the at least one additional planar spiral inductor form an array of planar spiral inductors, wherein the array of planar spiral inductors are positioned parallel to a surface.

18. The method according to claim 17, wherein the array of planar spiral inductors are separated into two or more separate regions, and wherein each separate region is configured to be activated only when a receiver is located in the charging region of the separate region.

19. The method according to claim 17, further comprising:

identifying a load impedance of devices located in the charging region of the array of planar spiral inductors; and

adjusting the power supply to increase the efficiency of power transfer from the array of planar spiral inductors to the devices located in the charging region of the array of planar spiral inductors.

20. The method according to claim 17, further comprising detecting the impedance mismatch between the array of planar spiral inductors and devices located in the charging region of the array of planar spiral inductors;

and providing an adaptive impedance matching network, wherein the adaptive impedance matching network tunes the array of planar spiral inductors to resonance based on the detected impedance mismatch.

21. The method according to claim 17, wherein the thickness of each planar spiral inductor of the array of planar spiral inductors is greater than two times the skin depth of the corresponding planar spiral inductor.

22. A system, comprising:

means for generating a wireless field having a charging region for powering a device, the means for generating the wireless field comprising a planar spiral inductor, the planar spiral inductor located in a plane and having a conductive trace having an increasing width which does not decrease from an outer periphery of the planar spiral inductor to the center of a spiral formed by the planar spiral inductor; and

means for supporting a receiver, the receiver configured to receive power from the planar spiral inductor when the receiver is positioned within the charging region so as to provide power to the device.

23. The system according to claim 22, further comprising at least one additional planar spiral inductor, wherein the width of each of the at least one additional planar spiral inductor'"'"'s trace becomes wider as the trace spirals toward the center of a spiral formed by the at least one additional planar spiral inductor, and wherein the widening of each trace as the trace spirals toward the center of the spiral formed by the at least one additional planar spiral inductor produces a more even magnetic field distribution.

24. The system according to claim 23, wherein the planar spiral inductor and the at least one additional planar spiral inductor form an array of planar spiral inductors, wherein the array of planar spiral inductors are positioned parallel to a surface.