MULTI-COIL INDUCTION

• US 20150303699A1
• Filed: 04/18/2014
• Published: 10/22/2015
• Est. Priority Date: 04/18/2014
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Jol, Eric S., Thompson, Paul J., Wagman, Daniel C.
• Granted Patent: US 10,447,079 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H02J 50/10 using inductive coupling
• 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 7/0047 with monitoring or indicating devices or circuits

Abstract

Methods and apparatuses for improved efficiency of power transfer across an inductive charging interface by selectively activating, deactivating, or modifying one or more of a plurality of transmit coils associated with an inductive power transmitter are disclosed.

Claims

1. An adaptive power control system for an electromagnetic induction power transfer apparatus comprising:

an inductive power transmitter, comprising;

a first magnetic field source defining an alignment axis;

a power supply configured to switch between an active state and an inactive state at a selectable duty cycle;

a plurality of power-transmitting inductors each coupled to the power supply and positioned with respect to the alignment axis at axially symmetric intervals; and

a processor operatively connected to the power supply and configured to vary a power transmitted by the plurality of power-transmitting inductors in response to an indication of a programmable load.

2. The adaptive power control system of claim 1, the inductive power transmitter further comprising a power controller coupled to each of the plurality of power-transmitting inductors.

3. The adaptive power control system of claim 2, wherein the power controller is configured to electrically couple the power supply to a selected subset of the plurality of power-transmitting inductors.

4. The adaptive power control system of claim 2, wherein the power controller is configured to determine a power transfer efficiency for each of the plurality of power-transmitting inductors.

5. The adaptive power control system of claim 4, wherein the power controller is configured to electrically couple the power supply to a selected subset of the plurality of power-transmitting inductors, wherein the selected subset is determined to have the highest power transfer efficiency of the plurality of power-transmitting inductors.

6. The adaptive power control system of claim 1, wherein the first magnetic field source comprises a permanent magnet.

7. The adaptive power control system of claim 1, wherein the second magnetic field source comprises a permanent magnet.

8. The adaptive power control system of claim 1, wherein the plurality of power-transmitting inductors are positioned in a circular pattern surrounding the first magnetic field source.

9. The adaptive power control system of claim 1, wherein the plurality of power-transmitting inductors are arranged in a plurality of layers.

10. The adaptive power control system of claim 1, wherein the plurality of power-receiving inductors are arranged in a set of layers offset from one another.

11. The adaptive power control system of claim 1, further comprising an inductive power receiver comprising:

a second magnetic field source configured to be attracted to the first magnetic field source;

a plurality of power-receiving inductors positioned around the second magnetic field source, each positioned inductively proximate a corresponding one of the plurality of power-transmitting inductors; and

a programmable load.

12. The adaptive power control system of claim 11, wherein the power controller is configured to electrically couple a selected subset of the plurality of power-receiving inductors to at least one a rechargeable battery and the programmable load.

13. The adaptive power control system of claim 11, wherein the power controller is configured to determine a power transfer efficiency for each of the plurality of power-receiving inductors.

14. The adaptive power control system of claim 13, wherein the power controller is configured to electrically couple a selected subset of the plurality of power-receiving inductors to at least one a rechargeable battery and the programmable load, wherein the selected subset is determined to have a higher power transfer efficiency than each of the unselected power-receiving inductors of the plurality of power-receiving inductors.

15. The adaptive power control system of claim 1, wherein at least one of the plurality of power-transmitting inductors coupled to a signal generator.

16. The adaptive power control system of claim 15, wherein the signal generator is adapted to apply a first signal to the at least one of the plurality of power-transmitting inductors the first signal provided at a higher frequency than the selectable duty cycle.

17. An electromagnetic induction power receiver comprising:

a magnetic field source configured to be attracted to an electromagnetic induction power transmitter;

a plurality of power-receiving inductors positioned around the magnetic field source, each positioned inductively proximate a corresponding one of the plurality of power-transmitting inductors; and

a programmable load.

18. The electromagnetic induction power receiver of claim 17, wherein the magnetic field source comprises a permanent magnet.

19. The electromagnetic induction power receiver of claim 17, wherein the plurality of power-receiving inductors are arranged in a plurality of layers.

20. The electromagnetic induction power receiver of claim 17, the inductive power receiver further comprising a power controller coupled to each of the plurality of power-receiving inductors.

21. The electromagnetic induction power receiver of claim 20, wherein the power controller is configured to electrically couple a selected subset of the plurality of power-receiving inductors to at least one a rechargeable battery and the programmable load.

22. The electromagnetic induction power receiver of claim 20, wherein the power controller is configured to determine a power transfer efficiency for each of the plurality of power-receiving inductors.

23. The electromagnetic induction power receiver of claim 22, wherein the power controller is configured to electrically couple a selected subset of the plurality of power-receiving inductors to at least one a rechargeable battery and the programmable load, wherein the selected subset is determined to have a higher power transfer efficiency than each of the unselected power-receiving inductors of the plurality of power-receiving inductors.

24. A method of modifying power output of an electromagnetic induction power transfer apparatus comprising:

determining the presence of an inductive power receiver;

determining an orientation of the inductive power receiver; and

adjusting output of one or more power-transmitting inductors in response to the determined orientation.

25. A method of managing temperature of an electromagnetic induction power transfer apparatus comprising:

selecting a first transmit coil from a plurality of transmit coils;

connecting the first transmit coil to a power source for a first selected period of time;

selecting a second transmit coil from the plurality of transmit coils; and

connecting the second transmit coil to the power source for a second selected period of time.

26. The method of claim 25, wherein the first selected period of time is based at least in part on a temperature of the electromagnetic induction power transfer apparatus.

27. The method of claim 25, wherein the second transmit coil is selected, at least in part, on the second transmit coil'"'"'s distance from the first transmit coil.