Inductor system having shared material for flux cancellation

• US 10,199,160 B2
• Filed: 03/22/2018
• Issued: 02/05/2019
• Est. Priority Date: 08/08/2016
• Status: Active Grant

• Current Assignee: WiTricity Corporation
• Original Assignee: WiTricity Corporation
• Inventors: Lestoquoy, Guillaume
• Primary Examiner(s): Mehari, Yemane
• Application Number:
  US15/928,314
• Publication Number:
  US 20180218832A1
• Time in Patent Office: 320 Days
• Field of Search: 323356, 307107, 3184004, 31840035, 318780
• CPC Class Codes: H01F 27/38 Auxiliary core members; Auxiliary coils or windings
• CPC Class Codes: H01F 27/385 for reducing harmonics
• CPC Class Codes: H01F 3/14 Constrictions; Gaps, e.g. air-gaps in magnetic shunt paths H01F3/12
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries

Abstract

Methods and apparatus for flux cancellation includes first and second inductors. A system cam include first and second inductors and a layer of magnetic material disposed between the first inductor and the second inductor. In embodiments, when the inductors are driven with a respective oscillating current, at least a portion of magnetic flux generated by the first inductor is substantially canceled by at least a portion of magnetic flux generated by the second inductor in the layer of magnetic material.

Claims

1. A system comprising:

a first inductor;

a second inductor; and

a layer of magnetic material disposed between the first inductor and the second inductor, wherein the first and second inductors are configured such that, when each is driven with a respective oscillating current, at least a portion of magnetic flux generated by the first inductor is substantially canceled by at least a portion of magnetic flux generated by the second inductor in the layer of magnetic material.

2. The system of claim 1 wherein the first and second inductors are disposed in first and second E-shaped cores, respectively.

3. The system of claim 2 wherein the magnetic material layer in combination with the first and second inductors determine respective inductances of first and second inductors during operation of the system.

4. The system of claim 1 wherein a net of the canceled flux from the first and second inductors is substantially zero in a portion of the magnetic material layer when the oscillating current through each of the first and second inductors substantially matches.

5. The system of claim 1, wherein the first and second inductors are coupled to a source coil of a wireless resonant power transmitter.

6. The system according to claim 1, wherein the first and second inductors are coupled to a device coil of a wireless resonant power receiver.

7. The system according to claim 1, wherein the first and second inductors comprise respective planar windings.

8. The system according to claim 1, wherein the layer of magnetic material is shared with further circuit components.

9. A method comprising:

disposing a layer of magnetic material between first and second inductors; and

driving with an oscillating current the first and second inductors such that at least a portion of a first magnetic flux generated by the first inductor is canceled by at least a portion of a second magnetic flux generated by the second inductor,

wherein the magnetic material layer in combination with the first and second inductors determine respective inductances of first and second inductors during operation of the system.

10. The method of claim 9, wherein a net of the canceled flux from the first and second inductors is substantially zero in a portion of the magnetic material layer when oscillating current through each of the first and second inductors substantially matches.

11. The method of claim 9 wherein the first and second inductors are disposed in first and second E-shaped cores, respectively.

12. The method of claim 10 wherein the magnetic material layer in combination with the first and second inductors determine respective inductances of first and second inductors during operation of the system.

13. The method of claim 9, wherein the first and second inductors are coupled to a source coil of a wireless resonant power transmitter.

14. The method according to claim 9, wherein the first and second inductors are coupled to a device coil of a wireless resonant power receiver.

15. The method according to claim 9, wherein the first and second inductors comprise respective planar windings.

16. The method according to claim 9, wherein the layer of magnetic material is shared with further circuit components.

17. A system comprising:

a first inductor;

a second inductor substantially magnetically decoupled from the first inductor; and

a layer of magnetic material disposed between the first inductor and the second inductor;

wherein when the first and second inductors are driven with respective oscillating currents, at least a portion of magnetic flux generated by the first inductor is substantially canceled by at least a portion of magnetic flux generated by the second inductor in the layer of magnetic material.

18. The system of claim 17 wherein the first and second inductors are disposed in first and second E-shaped cores, respectively.

19. The system of claim 17 wherein a net of the canceled flux from the first and second inductors is substantially zero in a portion of the magnetic material layer when the oscillating current through each of the first and second inductors substantially matches.

20. The system of claim 17 wherein the magnetic material layer in combination with the first and second inductors determine respective inductances of first and second inductors during operation of the system.