ICPT SYSTEM, COMPONENTS AND DESIGN METHOD

• US 20130181536A1
• Filed: 06/15/2011
• Published: 07/18/2013
• Est. Priority Date: 06/15/2010
• Status: Abandoned Application

• Current Assignee: Apple Inc.
• Original Assignee: PowerbyProxi Limited (Apple Inc.)
• Inventors: Bhargawa, Kunal, Mishriki, Fady
• Application Number:
  US13/704,398
• Publication Number:
  US 20130181536A1
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: G06F 30/39 Circuit design at the physical level physical level design for reconfigurable circuits G06F30/347
• CPC Class Codes: H01F 27/02 Casings
• CPC Class Codes: H01F 27/36 Electric or magnetic shields or screens movable for varying inductance H01F21/10
• CPC Class Codes: H01F 27/363 made of electrically conductive material
• 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: H02J 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields

Abstract

A method for removing the effects of metallic objects in an inductively coupled power transfer system by providing a metallic casing around transmitting and/or receiving coils and compensating for their effect in the design of transmitting and/or receiving circuits. Whilst incurring some loss in performance this design reduces variability due to different metallic influences in an operating environment. Power transmitters and receivers and a system including the power transmitter and the power receiver are also disclosed.

Claims

1. A method of designing a power transmitter for an inductively coupled power transfer system including the steps of:

a. determining the inductance of a transmitting coil having an associated metallic casing; and

b. designing a transmitter circuit for the transmitting coil based on the inductance determined in step a.

2. A method as claimed in claim 1 wherein the power transmitter is designed to operate at a resonant frequency.

3. A method as claimed in claim 1 wherein the power transmitter is designed to operate at a frequency other than a resonant frequency.

4. A method as claimed in claim 3 wherein the transfer function of the power transmitter is selected to facilitate control of power transfer of the power transmitter.

5. A method as claimed in claim 1 wherein the transmitting coil is generally cylindrical and the metallic casing includes a ring about the periphery of the transmitting coil.

6. A method as claimed in claim 5 wherein the metallic casing includes a metallic end plate at one end of the transmitting coil.

7. A method as claimed in claim 1 wherein the transmitting coil is a spiral wound coil.

8. A method as claimed in claim 1 wherein the transmitting coil is a lumped coil.

9. A method as claimed in claim 1 wherein the transmitter circuit includes a boost converter.

11. A method as claimed in claim 10 wherein the power transmitter is designed in accordance with the method of claim 1.

10. A method of designing a power receiver for an inductively coupled power transfer system including a power transmitter and a power receiver, the method including the steps of:

a. determining the inductance of a receiving coil having an associated metallic casing that partially encloses the receiving coil; and

b. designing a receiver circuit based on the resonant frequency of the transmitter and the determined inductance in step a.

12. A method as claimed in claim 10 wherein the power receiver is designed to operate at the resonant frequency of the power transmitter.

13. A method as claimed in claim 10 wherein the power receiver is designed to operate over a frequency range about the resonant frequency of the power transmitter so as to control power transfer.

14. A method as claimed in claim 10 wherein the receiving coil is generally cylindrical and the metallic casing includes a ring about the periphery of the receiving coil.

15. A method as claimed in claim 14 wherein the metallic casing includes a metallic end plate at one end of the receiving coil.

16. A method as claimed in claim 10 wherein the receiving coil is a spiral wound coil.

17. A method as claimed in claim 10 wherein the receiving coil is a lumped coil.

18. A method as claimed in claim 10 wherein the receiving circuit includes a buck converter.

28. A power receiver as claimed in claim 27 wherein the power transmitter is designed in accordance with the method of any one of claims 10 to 18.

19. A power transmitter for an inductively coupled power transfer system comprising:

a. a transmitting coil having an associated metallic casing; and

b. a transmitter circuit for the transmitting coil wherein the transmitter circuit is designed for operation of the transmitting coil taking into account the effect of the associated metallic casing.

20. A power transmitter as claimed in claim 19 wherein the transmitter circuit is designed to operate at a resonant frequency when driving the transmitting coil.

21. A power transmitter as claimed in claim 19 wherein the transmitter circuit is designed to operate at other than a resonant frequency when driving the transmitting coil.

22. A power transmitter as claimed in claim 21 wherein the transfer function of the power transmitter is selected to facilitate control of power transfer of the power transmitter.

23. A power transmitter as claimed in claim 19 wherein the transmitting coil is generally cylindrical and the metallic casing includes a ring about the periphery of the transmitting coil.

24. A power transmitter as claimed in claim 23 wherein the metallic casing includes a metallic end plate at one end of the transmitting coil.

25. A power transmitter as claimed in claim 19 wherein the transmitting coil is a spirally wound coil.

26. A power transmitter as claimed in claim 19 wherein the transmitting coil is a lumped coil.

36. A system including a power transmitter as claimed in claim 19 and a power receiver.

27. A power receiver for an inductively coupled power transfer system comprising:

a. a receiving coil having an associated metallic casing that partially encloses the receiving coil; and

b. a receiving circuit for the receiving coil wherein the receiving circuit is designed for operation of the receiving coil taking into account the effect of the associated metallic casing.

29. A power receiver as claimed in claim 27 wherein the power receiver is designed to operate at the resonant frequency of the power transmitter.

30. A power receiver as claimed in claim 27 wherein the operating frequency of the power receiver can be adjusted over a frequency range about the resonant frequency of the power transmitter so as to control power transfer.

31. A power receiver as claimed in claim 27 wherein the receiving coil is generally cylindrical and the metallic casing includes a ring about the periphery of the receiving coil.

32. A power receiver as claimed in claim 31 wherein the metallic casing includes a metallic end plate at one end of the receiving coil.

33. A power receiver as claimed in claim 27 wherein the receiving coil is a spiral wound coil.

34. A power receiver as claimed in claim 27 wherein the receiving coil is a lumped coil.

35. A power receiver as claimed in claim 27 wherein the receiving circuit includes a buck converter.

37-38. -38. (canceled)