LOCALIZED CHARGING, LOAD IDENTIFICATION AND BI-DIRECTIONAL COMMUNICATION METHODS FOR A PLANAR INDUCTIVE BATTERY CHARGING SYSTEM

• US 20090108805A1
• Filed: 10/30/2007
• Published: 04/30/2009
• Est. Priority Date: 10/30/2007
• Status: Active Grant

• Current Assignee: City University of Hong Kong
• Original Assignee: City University of Hong Kong
• Inventors: Ho, Wing Choi, Liu, Xun, Hui, Ron Shu Yuen, Chan, Wing Cheong
• Granted Patent: US 7,915,858 B2
• Time in Patent Office: Days
• US Class Current: 320/108
• CPC Class Codes: H01F 2017/0073 with a special conductive pattern, e.g. flat spiral
• 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 50/402 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 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• CPC Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge

Abstract

Methods and principles are described for systematizing localized charging, load identification and bi-directional communication in a planar battery charging system. Also described is control circuitry for selectively energizing a primary winding when a load is placed on the platform. The optimization of the size of the receiver winding compared to the transmitter winding is discussed, while the associated communication methods include techniques for load identification, compatibility checks, hand-shaking and communication of charging status.

Claims

1. A planar battery charging system, comprising:

a primary power transmission side formed of an array of primary windings adapted to generate magnetic flux substantially perpendicular to a charging surface; and

a secondary power receiving side comprising a secondary winding associated with a battery to be charged and being adapted to receive said magnetic flux when placed on said charging surface, said secondary winding being provided with electromagnetic shielding on the side of said winding opposite from the side to be placed on the charging surface;

wherein the relative dimensions of the primary windings and the secondary winding are chosen to meet the conditions that (a) the area enclosed by the secondary winding is greater than the area enclosed by a primary winding, (b) the secondary winding or said shielding will always fully enclose a primary winding when a secondary winding is placed on said charging surface, and (c) a single primary winding generates sufficient power to charge a said battery.

2. The planar battery charging system as claimed in claim 1, wherein the ratio of the area enclosed by the secondary winding to the area enclosed by a primary winding is minimized while being consistent with conditions (a) and (b).

3. The planar battery charging system as claimed in claim 1, wherein said primary windings are arranged in a regular array of identical size and shape.

4. The planar battery charging system as claimed in claim 1, wherein said array of primary windings is divided into a plurality of zones and wherein within each zone said primary windings are of identical size and shape.

5. The planar battery charging system as claimed in claim 1, wherein said primary windings are provided in a stacked structure.

6. The planar battery charging system as claimed in claim 5, wherein a primary winding is formed of two or more connected coils separated by a substrate.

7. The planar battery charging system as claimed in claim 1, wherein only a single primary winding is excited when a secondary winding is placed on said charging surface.

8. The planar battery charging system as claimed in claim 1, wherein said electromagnetic shielding extends beyond the dimensions of the secondary winding.

9. The planar battery charging system as claimed in claim 1, wherein only a primary winding that is covered when a secondary winding is placed on said charging surface is excited.

10. A planar battery charging system, comprising:

a primary power transmission side formed of an array of primary windings adapted to generate magnetic flux substantially perpendicular to a charging surface; and

a secondary power receiving side comprising a secondary winding associated with a battery to be charged and being adapted to receive said magnetic flux when placed on said charging surface, wherein when a said secondary winding is placed on said charging surface only a single primary winding is excited to generate magnetic flux to charge said battery.

11. The planar battery charging system as claimed in claim 10, further comprising a matrix switching array for enabling a selected primary winding to be excited.

12. The planar battery charging system as claimed in claim 10, wherein when excited a single primary winding provides sufficient magnetic flux to charge a said battery.

13. The planar battery charging system as claimed in claim 10, further comprising means to detect the presence and location on said charging surface of a said secondary winding.

14. A planar battery charging system, comprising:

a primary power transmission side formed of an array of primary windings adapted to generate magnetic flux substantially perpendicular to a charging surface;

a secondary power receiving side comprising a secondary winding associated with a battery to be charged and being adapted to receive said magnetic flux when placed on said charging surface; and

a matrix switching array for selectively exciting individual primary windings.

15. The planar battery charging system as claimed in claim 14, wherein said array of primary windings comprises a plurality of rows and a plurality of columns, wherein said matrix switching array comprises one switch per row and one switch per column, and wherein a winding to be excited is selected by closing the switches in the row and column corresponding to the location of the winding.

16. The planar battery charging system as claimed in claim 15, wherein said switches are controlled by a microprocessor control unit.

17. The planar battery charging system as claimed in claim 14, wherein said matrix switching array includes filter means.

18. A planar battery charging system, comprising:

a primary power transmission side formed of an array of primary windings adapted to generate magnetic flux substantially perpendicular to a charging surface;

a secondary power receiving side comprising a secondary winding associated with a battery to be charged and being adapted to receive said magnetic flux when placed on said charging surface; and

data communication means for enabling data communication between the primary side and the secondary side.

19. The planar battery charging system as claimed in claim 18, wherein data transfer from said primary side to said secondary side is achieved by modulating the excitation of a primary winding.

20. The planar battery charging system as claimed in claim 18, wherein data transfer from said secondary side to said primary side is achieved by modulating a parameter on said secondary side.

21. The planar battery charging system as claimed in claim 20, wherein data transfer from said secondary side to said primary side is achieved by changing the loading conditions.

22. The planar battery charging system as claimed in claim 18, wherein said data communication comprises detection by said primary side of a load to be charged on said secondary side.

23. The planar battery charging system as claimed in claim 21, wherein the detection of a load to be charged includes the detection of the location of said load on said charging surface.

24. The planar battery charging system as claimed in claim 18, wherein said data communication comprises hand-shaking and compatibility checks between said primary side and a load to be charged.

25. The planar battery charging system as claimed in claim 18, wherein said data communication comprises determination of the charging status of a battery.