Inductor system having shared material for flux cancellation

• US 9,959,972 B2
• Filed: 08/08/2017
• Issued: 05/01/2018
• 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:
  US15/671,680
• Publication Number:
  US 20180040416A1
• Time in Patent Office: 266 Days
• Field of Search: 323356, 3184004, 31840035, 318780, 307104
• 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, wherein the first inductor is configured for coupling to a first energy source and the second inductor is configured for coupling to a second energy source. A layer of magnetic material is disposed between the first and second inductors, wherein the first and second inductors are configured such that, when driven with an oscillating current, magnetic flux generated by the first inductor is substantially canceled by magnetic flux generated by the second inductor in the layer of magnetic material.

Claims

1. A system comprising:

a first inductor driven by a first oscillating current generated by a first energy source;

a second inductor driven by a second oscillating current generated by a second energy source, 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 its respective oscillating current, magnetic flux generated by the first inductor is substantially canceled by 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 5, wherein the power transmitter forms a part of a charging platform.

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, wherein the first inductor is electrically coupled to a first energy source and the second inductor is electrically coupled to a second energy source; and

driving with an oscillating current the first and second inductors such that a first magnetic flux generated by the first inductor is canceled by 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 13, wherein the power transmitter forms a part of a charging platform.

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 driven by a first oscillating current;

a second inductor driven by a second oscillating current and substantially 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 their respective oscillating current, magnetic flux generated by the first inductor is substantially canceled by 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.