SYSTEM AND METHOD FOR LOW LOSS WIRELESS POWER TRANSMISSION

• US 20130154383A1
• Filed: 09/12/2012
• Published: 06/20/2013
• Est. Priority Date: 12/16/2011
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: KASTURI, Sreenivas, GUPTA, Ashish, McFARLAND, Michael K.
• Granted Patent: US 9,270,342 B2
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/20 using microwaves or radio frequency waves
• CPC Class Codes: H02J 50/40 using two or more transmitting or receiving devices H02J50/50 takes precedence
• CPC Class Codes: H02J 50/60 responsive to the presence of foreign objects, e.g. detection of living beings
• CPC Class Codes: H02J 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
• CPC Class Codes: H04B 5/263 Multiple coils at either side
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer
• CPC Class Codes: Y02E 60/00 Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• CPC Class Codes: Y04S 40/121 using the power network as support for the transmission
• CPC Class Codes: Y04S 40/126 using wireless data transmission

Abstract

Systems and methods for low loss wireless power transmission are described herein. In one aspect, a transmission coil for transmitting wireless power comprises a first and second spiral coil. Each spiral coil comprises a plurality of turns. A center of the first spiral coil to an outermost turn of the first spiral coil defines a first cross section, and a center of the second spiral coil to an outermost turn of the second spiral coil defines a second cross section. Portions of the first spiral coil along the first cross section and the second spiral coil along the second cross section have a mutual inductance with respect to a receive coil greater than 65% of a maximum mutual inductance along the first and second cross sections. The second spiral coil is counter-wound relative to the first spiral coil.

Claims

1. A transmission coil for transmitting wireless power to a receive coil, the transmission coil comprising:

a first spiral coil comprising a plurality of turns, a center of the first spiral coil to an outermost turn of the first spiral coil defining a first cross section; and

a second spiral coil comprising a plurality of turns, a center of the second spiral coil to an outermost turn of the second spiral coil defining a second cross section, portions of the first spiral coil along the first cross section and the second spiral coil along the second cross section having a mutual inductance with respect to a receive coil greater than 65% of a maximum mutual inductance along the first and second cross sections, the second spiral coil counter-wound relative to the first spiral coil.

2. The transmission coil of claim 1, wherein the second spiral coil is located above or below the first spiral coil.

3. The transmission coil of claim 1, wherein the second spiral coil is interwoven with the first spiral coil.

4. The transmission coil of claim 3, wherein a total length of the second spiral coil is a same length as a total length of the first spiral coil, and the second spiral coil is substantially shaped as a reflection of the first spiral coil.

5. The transmission coil of claim 1, wherein the receive coil comprises a first receive coil and a second receive coil.

6. The transmission coil of claim 1, wherein the second spiral coil is located substantially on a common plane with the first spiral coil and has a common center with first spiral coil,

the first and second cross sections are located substantially on a common plane, and

a turn distance from the common center to a center of a particular turn along the first or second cross section of the first or second spiral coil is a function of a distance from the common center to the outermost turn of the first or second spiral coil, a first value corresponding to spacings between turns of the first or second spiral coil, a sum of a total number of turns of the first and second spiral coils, and a first number corresponding to the particular turn.

7. The transmission coil of claim 1, wherein the first and second spiral coil are electrically coupled to a driver circuit, substantially located on a common plane, and configured to wirelessly transmit power at a level sufficient to charge or power a receiver device.

8. The transmission coil of claim 1, wherein input signals for first and second spiral coil are configured to be within a frequency range of 6.5 Megahertz to 7 Megahertz.

9. The transmission coil of claim 1, wherein each turn of the first and second spiral coil is configured to have a turn radius greater than a minimum turn radius of 5 millimeters.

10. A method for transmitting wireless power to a receive coil, the method comprising:

driving with electrical current a first spiral coil comprising a plurality of turns, a center of the first spiral coil to an outermost turn of the first spiral coil defining a first cross section; and

driving with electrical current a second spiral coil comprising a plurality of turns, a center of the second spiral coil to an outermost turn of the second spiral coil defining a second cross section, portions of the first spiral coil along the first cross section and the second spiral coil along the second cross section having a mutual inductance with respect to a receive coil greater than 65% of a maximum mutual inductance along the first and second cross sections, the second spiral coil counter-wound relative to the first spiral coil.

11. The method of claim 10, wherein the second spiral coil is located above or below the first spiral coil.

12. The method of claim 10, wherein the second spiral coil is interwoven with the first spiral coil.

13. The method of claim 12, wherein a total length of the second spiral coil is a same length as a total length of the first spiral coil, and the second spiral coil is substantially shaped as a reflection of the first spiral coil.

14. The method of claim 10, wherein the receive coil comprises a first receive coil and a second receive coil.

15. The method of claim 10, wherein the second spiral coil is located substantially on a common plane with the first spiral coil and has a common center with first spiral coil,

the first and second cross sections are located substantially on a common plane, and

a turn distance from the common center to a center of a particular turn along the first or second cross section of the first or second spiral coil is a function of a distance from the common center to the outermost turn of the first or second spiral coil, a first value corresponding to spacings between turns of the first or second spiral coil, a sum of a total number of turns of the first and second spiral coils, and a first number corresponding to the particular turn.

16. The method of claim 10, wherein the first and second spiral coil are electrically coupled to a driver circuit, substantially located on a common plane, and configured to wirelessly transmit power at a level sufficient to charge or power a receiver device.

17. The method of claim 10, wherein input signals for first and second spiral coil are configured to be within a frequency range of 6.5 Megahertz to 7 Megahertz.

18. The method of claim 10, wherein each turn of the first and second spiral coil is configured to have a turn radius greater than a minimum turn radius of 5 millimeters.