Methods for Steering a Magnetic Field for Smart Wireless Power Transmission

• US 20160134126A1
• Filed: 11/07/2014
• Published: 05/12/2016
• Est. Priority Date: 11/07/2014
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Tillotson, Brian J., Zeng, Peng
• Granted Patent: US 9,929,569 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01B 7/30 for measuring angles or tapers; for testing the alignment of axes
• CPC Class Codes: G01R 19/04 Measuring peak values or amplitude or envelope of ac or of pulses
• 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 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: H02J 50/005 Mechanical details of housing or structure aiming to accommodate the power transfer means, e.g. mechanical integration of coils, antennas or transducers into emitting or receiving devices
• 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 50/80 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: H04B 5/263 Multiple coils at either side
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

Systems and methods for mitigating constraints associated with wireless power transmission in applications where the position and orientation of the desired magnetic field changes over time, for example, because the position and orientation of the receiver being powered changes over time or because different receivers having different positions and orientations are being powered at different times. In accordance with some embodiments, the system employs a plurality of wireless power transmitters in a defined space, each transmitter consisting of individual coils oriented orthogonally relative to each other. Using field interference amongst these individual coils as well as amongst the transmitters they form, one can actively control the wireless power field intensity and orientation at any given point in the defined space. This allows for methods to steer the power transmission towards a specific target at a specific angle.

Claims

1. A method for wirelessly transmitting power to an electric device, comprising:

providing a transmitter having at least two transmitter coils arranged at fixed positions and orientations relative to each other;

locating the transmitter with respect to a space containing a first electric device having a first receiver coil; and

providing respective electric currents to respective transmitter coils of the transmitter which produce at a first time a first resultant magnetic field having a magnetic field line which is located along the axis of the first receiver coil of the first electric device.

2. The method as recited in claim 1, wherein the axis of the first receiver coil of the first electric device is not collinear with an axis of any of the transmitter coils.

3. The method as recited in claim 1, wherein the transmitter coils of the transmitter are mutually orthogonal.

4. The method as recited in claim 1, further comprising:

determining an orientation of an axis of the first receiver coil of the first electric device relative to a frame of reference of the transmitter; and

computing amplitudes for the respective electric currents based at least in part on the orientation of the axis of the first receiver coil of the first electric device.

5. The method as recited in claim 4, wherein said step of determining an orientation of the axis of the first receiver coil of the first electric device comprises:

creating a local magnetic field at each coordinate and each orientation in a space; and

detecting a decrease in the energy in the transmitter.

6. The method as recited in claim 4, wherein said step of determining an orientation of the axis of the first receiver coil of the first electric device coil comprises:

sweeping ratios of respective powers supplied to each transmitter coil; and

detecting a power drain in the transmitter.

7. The method as recited in claim 1, wherein the space contains a second electric device having a receiver coil and having a location different than the location of the first electric device, further comprising providing respective electric currents to respective transmitter coils of the transmitter which produce at a second time different than said first time a second resultant magnetic field having a magnetic field line which is located along the axis of the receiver coil of the second electric device.

8. The method as recited in claim 7, further comprising:

retrieving unit vectors and amplitudes associated with said first resultant magnetic field from a look-up table prior to said first time; and

retrieving unit vectors and amplitudes associated with said second resultant magnetic field from said look-up table prior to said second time.

9. The method as recited in claim 1, wherein the first electric device has a second receiver coil having an axis different than the axis of said first receiver coil, further comprising providing respective electric currents to respective transmitter coils of the transmitter which produce at a second time different than said first time a second resultant magnetic field having a magnetic field line which is located along the axis of the second receiver coil of the first electric device.

10. A system for wireless power transmission comprising:

a receiver coil having an axis;

first, second and third transmitter coil components having axes which are mutually orthogonal;

a computer system programmed to compute respective amplitudes of respective currents to be supplied to said first, second and third transmitter coil components to generate a resultant magnetic field having a magnetic field line which is located along the axis of said receiver coil; and

means for supplying said respective currents having said respective amplitudes to said first, second and third transmitter coil components respectively.

11. The system as recited in claim 10, wherein each of said first, second and third transmitter coil components comprises a respective transmitter coil.

12. The system as recited in claim 10, wherein said first transmitter coil component comprises a first transmitter coil, said second transmitter coil component comprises mutually parallel second and third transmitter coils, and said third transmitter coil component comprises mutually parallel fourth and fifth transmitter coils, said second and third transmitter coils being disposed on opposite sides of said first transmitter coil, and said fourth and fifth transmitter coils being disposed on opposite sides of said first transmitter coil respectively above and below said second and third transmitter coils.

13. The system as recited in claim 10, wherein said receiver coil is a winding of an electric motor.

14. A method for wirelessly transmitting power to an electric device, comprising:

providing a first transmitter having at least two transmitter coils arranged at fixed positions and orientations relative to each other;

providing a second transmitter having at least two transmitter coils arranged at fixed positions and orientations relative to each other;

locating the first and second transmitters on different sides of a space containing a first electric device having a first receiver coil; and

providing respective electric currents to respective transmitter coils of the first and second transmitters which produce at a first time a first resultant magnetic field having a magnetic field line which is located along the axis of the first receiver coil of the first electric device.

15. The method as recited in claim 14, further comprising:

determining an orientation of an axis of the receiver coil of the electric device relative to a frame of reference of the first and second transmitters; and

computing amplitudes for the respective electric currents based at least in part on the orientation of the axis of the receiver coil of the first electric device.

16. The method as recited in claim 14, wherein the space contains a second electric device having a receiver coil and having a location different than the location of the first electric device, further comprising providing respective electric currents to respective transmitter coils of the first and second transmitters which produce at a second time different than said first time a second resultant magnetic field having a magnetic field line which is located along the axis of the receiver coil of the second electric device.

17. The method as recited in claim 14, wherein the first electric device has a second receiver coil having an axis different than the axis of said first receiver coil, further comprising providing respective electric currents to respective transmitter coils of the transmitter which produce at a second time different than said first time a second resultant magnetic field having a magnetic field line which is located along the axis of the second receiver coil of the first electric device.

18. The method as recited in claim 17, wherein said first electric device is an electric motor and said first and second receiver coils are first and second windings respectively of said electric motor.

19. The method as recited in claim 14, wherein the space contains a second electric device having a location different than the location of the first electric device, and said first resultant magnetic field produced at said first time has zero magnetic flux at the location of said second electric device.

20. A system for wireless power transmission comprising:

a receiver coil having an axis;

a gimbal arrangement;

a transmitter coil having an axis and mounted to said gimbal arrangement;

a first actuator coupled to said gimbal arrangement for changing an azimuth angle of said axis of said transmitter coil;

a second actuator coupled to said gimbal arrangement for changing an elevation angle of said axis of said transmitter coil;

a computer system programmed to control said first and second actuators and compute an amplitude of current to be supplied to said transmitter coil to generate a resultant magnetic field having a magnetic field line which is located along said axis of said receiver coil; and

means for supplying said current having said respective amplitude to said transmitter coil.