Wireless power transfer system coil arrangements and method of operation

• US 9,472,338 B2
• Filed: 03/08/2013
• Issued: 10/18/2016
• Est. Priority Date: 09/11/2012
• Status: Active Grant

• Current Assignee: WiTricity Corporation
• Original Assignee: Qualcomm, Inc.
• Inventors: Keeling, Nicholas A, Kissin, Michael
• Primary Examiner(s): BARNIE, REXFORD N
• Assistant Examiner(s): Tran, Thai
• Application Number:
  US13/791,503
• Publication Number:
  US 20140070623A1
• Time in Patent Office: 1,320 Days
• Field of Search: 307/104
• US Class Current: 1/1
• CPC Class Codes: B60L 53/122 Circuits or methods for driving the primary coil, e.g. supplying electric power to the coil
• CPC Class Codes: B60L 53/126 Methods for pairing a vehicle and a charging station, e.g. establishing a one-to-one relation between a wireless power transmitter and a wireless power receiver
• CPC Class Codes: B60L 53/36 by positioning the vehicle
• CPC Class Codes: H01F 2003/005 Magnetic cores for receiving several windings with perpendicular axes, e.g. for antennae or inductive power transfer
• CPC Class Codes: H01F 2005/027 wound on formers for receiving several coils with perpendicular winding axes, e.g. for antennae or inductive power transfer
• CPC Class Codes: H01F 27/38 Auxiliary core members; Auxiliary coils or windings
• 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 50/12 of the resonant type
• 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
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 90/12 Electric charging stations
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles
• CPC Class Codes: Y02T 90/167 Systems integrating technologies related to power network operation and communication or information technologies for supporting the interoperability of electric or hybrid vehicles, i.e. smartgrids as interface for battery charging of electric vehicles [EV] or hybrid vehicles [HEV]
• CPC Class Codes: Y04S 30/12 Remote or cooperative charging

Abstract

This disclosure provides systems, methods and apparatus for wireless power transfer and particularly wireless power transfer to remote systems such as electric vehicles. In one aspect the disclosure provides for an apparatus for wirelessly transmitting power. The apparatus includes a first conductive structure configured to generate a first magnetic field in response to receiving a first time-varying signal from a power source. The apparatus includes a second conductive structure configured to generate a second magnetic field in response to receiving a second time-varying signal from the power source. The first and second structures are positioned to maintain a substantial absence of mutual coupling between the first and second magnetic fields.

Claims

1. An apparatus for wirelessly transmitting power, the apparatus comprising:

a first conductive structure configured to generate a first magnetic field in response to receiving a first time-varying electrical current from a power source, the first conductive structure comprising a first loop and a second loop enclosing a first area and a second area, respectively, the first loop having a first surface and the second loop having a second surface that are substantially coplanar; and

a second conductive structure configured to generate a second magnetic field in response to receiving a second time-varying electrical current from the power source, the second conductive structure comprising a third loop enclosing a third area, the first and second structures positioned to maintain a substantial absence of mutual coupling between the first and second conductive structures.

2. The apparatus of claim 1, wherein the substantial absence of mutual coupling occurs at least in part when a net sum of the first magnetic field generated by the first conductive structure that intersects the second conductive structure is substantially zero.

3. The apparatus of claim 1, wherein the first conductive structure and the second conductive structure define an area in which the first and second magnetic fields at least partially overlap, and wherein the substantial absence of mutual coupling occurs at least in part when a collective effect of addition and subtraction of the first and second magnetic fields is substantially zero.

4. The apparatus of claim 1, wherein the first conductive structure and the second conductive structure are configured to wirelessly transmit power at a level sufficient to power or charge an electric vehicle via the first and second magnetic fields.

5. The apparatus of claim 1, wherein the third loop is positioned such that substantially a center of the third area is positioned substantially over a point between the first loop and the second loop.

6. The apparatus of claim 1, wherein the first and second loops comprise first and second coils, respectively, the first and second coils configured to be electrically connected to the power source, the power source configured to apply electric current to the first and second coils in the same direction in adjacent portions of the first and second coils.

7. The apparatus of claim 6, wherein the third loop

comprises a third coil wound to enclose the third area.

8. The apparatus of claim 1, wherein the first conductive structure has a substantially horizontally polarized magnetic moment, and wherein the second conductive structure has a substantially vertically polarized magnetic moment.

9. The apparatus of claim 1, wherein the first and second conductive structures are capacitively loaded and operable at a resonant frequency, wherein the resonant frequency is substantially equal to a resonant frequency of a third conductive structure configured to wirelessly receive power via the first and second magnetic fields.

10. The apparatus of claim 1, further comprising:

a position detection circuit configured to identify a relative position of a third conductive structure relative to the first and second conductive structures; and

a controller configured to control the first time-varying electrical current or the second time-varying electrical current based on the relative position.

11. A method of wirelessly transmitting power, the method comprising:

generating a first magnetic field via a first conductive structure in response to receiving a first time-varying electrical current from a power source, the first conductive structure comprising a first loop and a second loop enclosing a first area and a second area, respectively, the first loop having a first surface and the second loop having a second surface that are substantially coplanar; and

generating a second magnetic field via a second conductive structure in response to receiving a second time-varying electrical current from the power source, the second conductive structure comprising a third loop enclosing a third area, the first and second structures positioned to maintain a substantial absence of mutual coupling between the first and second conductive structures.

12. The method of claim 11, wherein the substantial absence of mutual coupling occurs at least in part when a net sum of the first magnetic field generated by the first conductive structure that intersects the second conductive structure is substantially zero.

13. The method of claim 11, wherein the first conductive structure and the second conductive structure define an area in which the first and second magnetic fields at least partially overlap, and wherein the substantial absence of mutual coupling occurs at least in part when a collective effect of addition and subtraction of the first and second magnetic fields is substantially zero.

14. The method of claim 11, wherein generating the first and second magnetic fields comprises generating the first and second magnetic fields at a level sufficient to wirelessly transfer power to power or charge an electric vehicle.

15. The method of claim 11, wherein the third loop is positioned such that substantially a center of the third area is positioned substantially over a point between the first loop and the second loop.

16. The method of claim 11, wherein the first and second loops comprise first and second coils, respectively, wherein the method further comprises applying electric current to the first and second coils in the same direction in adjacent portions of the first and second coils.

17. The method of claim 16, wherein the third loop comprises a third coil wound to enclose the third area.

18. The method of claim 11, wherein the first conductive structure has a substantially horizontally polarized magnetic moment, and wherein the second conductive structure has a substantially vertically polarized magnetic moment.

19. The method of claim 11, wherein the first and second conductive structures are capacitively loaded and operable at a resonant frequency, wherein the resonant frequency is substantially equal to a resonant frequency of a third conductive structure configured to wirelessly receive power via the first and second magnetic fields.

20. The method of claim 11, further comprising:

identifying a relative position of a third conductive structure relative to the first and second conductive structures; and

controlling the first time-varying electrical current or the second time-varying electrical current based on the relative position.

21. An apparatus for wirelessly transmitting power, the apparatus comprising:

a first means for generating a first magnetic field in response to receiving a first time-varying electrical current from a power source, the first generating means comprising a first loop and a second loop enclosing a first area and a second area, respectively, the first loop having a first surface and the second loop having a second surface that are substantially coplanar; and

a second means for generating a second magnetic field in response to receiving a second time-varying electrical current from the power source, the second generating means comprising a third loop enclosing a third area, the first and second generating means positioned to maintain a substantial absence of mutual coupling between the first and second generating means.

22. The apparatus of claim 21, wherein the substantial absence of mutual coupling occurs at least in part when a net sum of the first magnetic field generated by the first generating means that intersects the second generating means is substantially zero.

23. The apparatus of claim 21, wherein the first generating means and the second generating means define an area in which the first and second magnetic fields at least partially overlap, and wherein the substantial absence of mutual coupling occurs at least in part when a collective effect of addition and subtraction of the first and second magnetic fields is substantially zero.

24. The apparatus of claim 21, wherein the first generating means and the second generating means comprise means for wirelessly providing power at a level sufficient to power or charge an electric vehicle via the first and second magnetic fields.

25. The apparatus of claim 21, wherein the second generating means is positioned such that substantially a center of the third area is positioned substantially over a point between the first loop and the second loop.

26. The apparatus of claim 25, further comprising means for applying electric current to the first and second generating means in the same direction in adjacent portions of the first and second generating means.

27. The apparatus of claim 21, wherein the first generating means has a substantially horizontally polarized magnetic moment, and wherein the second generating means has a substantially vertically polarized magnetic moment.

28. The apparatus of claim 21, wherein the first and second generating means are capacitively loaded and operable at a resonant frequency, wherein the resonant frequency is substantially equal to a resonant frequency of a conductive structure configured to wirelessly receive power via the first and second magnetic fields.