Methods and apparatus for positioning a vehicle using foreign object detection

1. An apparatus for determining alignment information of a vehicle, the vehicle comprising an antenna circuit configured to modulate one or more electrical characteristics of the antenna circuit, the apparatus comprising:

a plurality of sensor circuits configured to generate a plurality of magnetic fields, at least one sensor circuit of the plurality of sensor circuits configured to sense the modulated electrical characteristic of the antenna circuit when the antenna circuit couples to the at least one sensor circuit via one of the plurality of magnetic fields; and

a controller circuit configured to determine alignment information of the vehicle based on the sensed modulated electrical characteristic.

2. The apparatus of claim 1 , wherein the at least one sensor circuit senses the modulated electrical characteristic as a modulated or varied impedance of the antenna circuit.

3. The apparatus of claim 1 , wherein each sensor circuit of the plurality of sensor circuits comprises a coil having one or more windings, the one or more windings driven with a current to generate one of the plurality of magnetic fields within a sense area above the at least one sensor circuit.

4. The apparatus of claim 1 , wherein the one or more electrical characteristics are modulated based on a distinct modulation pattern that uniquely identifies the antenna circuit, wherein the at least one sensor circuit is configured to sense the distinctive modulation pattern based on a distinct change of the disturbance in a magnetic field of the at least one sensor circuit in response to a degree of coupling to the antenna circuit.

5. The apparatus of claim 1 , wherein at least two or more sensor circuits of the plurality of sensor circuits are configured to sense the modulated electrical characteristic when the antenna circuit couples to the two or more sensor circuits, wherein the controller circuit is configured determine a position of the antenna circuit relative to the at least two sensor circuits based on a comparison of a magnitude of the sensed modulated electrical characteristic at each of the two or more sensor circuits.

6. The apparatus of claim 1 , wherein the modulated electrical characteristic uniquely identifies the vehicle, wherein the controller circuit is configured to retrieve a position of the antenna circuit on the vehicle and a position of a power receiving circuit on the vehicle based on uniquely identifying the vehicle via the sensed modulate electrical characteristic and determine a position of the antenna circuit relative to the power receiving circuit of the vehicle.

7. The apparatus of claim 1 , further comprising a power transmitting circuit positioned relative to at least two sensor circuits, wherein the controller circuit is configured to convert a position of the antenna circuit relative to the at least two sensor circuits to a position of the power receiving circuit relative to the power transmitting circuit based on the position of the antenna circuit relative to the power receiving circuit and a position of the power transmitting circuit relative to the at least two sensor circuits.

8. The apparatus of claim 1 , wherein the controller circuit is configured to determine alignment information for aligning a power receiving circuit with a power transmitting circuit based on a position of the power receiving circuit relative to the power transmitting circuit.

9. The apparatus of claim 1 , wherein the controller circuit is configured to communicate the alignment information to a user of the vehicle for aligning a power receiving circuit on the vehicle with a power transmitting circuit positioned relative to the sensor circuits.

10. The apparatus of claim 1 , wherein the plurality of sensor circuits are further configured to detect an object other than the antenna circuit of the vehicle.

11. A method for determining alignment information of a vehicle, the vehicle comprising an antenna circuit configured to modulate one or more electrical characteristics of the antenna circuit, the method comprising:

generating, by a plurality of sensor circuits, a plurality of magnetic fields;

sensing, by at least one sensor circuit of the plurality of sensor circuits, the modulated electrical characteristic of the antenna circuit when the antenna circuit couples to the at least one sensor circuit via one of the plurality of magnetic fields; and

determining alignment information of the vehicle based on the sensed modulated electrical characteristic.

12. The method of claim 11 , wherein sensing the modulated electrical characteristic comprises sensing a modulated or varied impedance of the antenna circuit.

13. The method of claim 11 , wherein generating a plurality of magnetic fields comprises driving one or more windings of the plurality of sensor circuits with a current to generate one of the plurality of magnetic fields within a sense area above the at least one sensor circuit.

14. The method of claim 11 , further comprising:

sensing a distinctive modulation pattern based on a distinct change of the disturbance in a magnetic field of the at least one sensor circuit in response to a degree of coupling to the antenna circuit, wherein the electrical characteristic is modulated based on the distinct modulation pattern; and

uniquely identifying the antenna circuit based on the sensed distinct modulation pattern.

15. The method of claim 11 , further comprising:

sensing the modulated electrical characteristic by at least two or more sensor circuits of the plurality of sensor circuits when the antenna circuit couples to the two or more sensor circuits; and

determining a position of the antenna circuit relative to the at least two sensor circuits based on a comparison of a magnitude of the sensed modulated electrical characteristic at each of the two or more sensor circuits.

16. The method of claim 11 , further comprising:

uniquely identifying the vehicle based on the sensed modulated electrical characteristic;

retrieving a position of the antenna circuit on the vehicle and a position of a power receiving circuit on the vehicle based on uniquely identifying the vehicle; and

determining a position of the antenna circuit relative to the power receiving circuit of the vehicle.

17. The method of claim 11 , further comprising converting a position of the antenna circuit relative to the at least two sensor circuits to a position of the power receiving circuit relative to a power transmitting circuit based on a position of the antenna circuit relative to the power receiving circuit and a position of the power transmitting circuit relative to the at least two sensor circuits.

18. The method of claim 11 , further comprising determining alignment information for aligning a power receiving circuit with a power transmitting circuit based on a position of the power receiving circuit relative to the power transmitting circuit.

19. The method of claim 11 , further comprising detecting an object other than the antenna circuit of the vehicle by the plurality of sensor circuits.

20. An apparatus for determining alignment information of a vehicle, the vehicle comprising an antenna circuit configured to modulate one or more electrical characteristics of the antenna circuit, the apparatus comprising:

means for generating a plurality of magnetic fields;

means for sensing the modulated electrical characteristic of the antenna circuit when the antenna circuit couples to the means for generating via one of the plurality of magnetic fields; and

means for determining alignment information of the vehicle based on the sensed modulated electrical characteristic.

21. The apparatus of claim 20 , wherein the means for generating a plurality of magnetic fields comprises a plurality of coils and at least one driving circuit configured to drive the plurality of coils with a current.

22. The apparatus of claim 20 , wherein the means for sensing the modulated electrical characteristic comprises a plurality of coils and at least one sensing circuit configured to sense the modulated electrical characteristic based on a disturbance in the magnetic field of the means for generating.

23. The apparatus of claim 20 , wherein the means for determining alignment information comprises a controller circuit.

24. The apparatus of claim 20 , wherein the means for sensing the modulated electrical characteristic senses a modulated or varied impedance of the antenna circuit.

25. The apparatus of claim 20 , further comprising:

means for sensing a distinctive modulation pattern based on a distinct change of the disturbance in a magnetic field of the means for generating in response to a degree of coupling to the antenna circuit, wherein the electrical characteristic is modulated based on the distinct modulation pattern; and

means for uniquely identifying the antenna circuit based on the sensed distinct modulation pattern.

26. The apparatus of claim 20 , further comprising means for determining a position of the antenna circuit relative the means for sensing based on a comparison of a magnitude of the sensed modulated electrical characteristic when the antenna circuit couples to the means for generating via at least two of the magnetic fields.

27. The apparatus of claim 20 , wherein the means for sensing is further configured to detect an object other than the antenna circuit of the vehicle by the plurality of sensor circuits.

28. A non-transitory computer readable medium comprising instructions that, when executed by a processor, cause a wireless power transfer system to perform a method for determining alignment information of a vehicle, the vehicle comprising an antenna circuit configured to modulate one or more electrical characteristics of the antenna circuit, the method comprising:

generating, by a plurality of sensor circuits, a plurality of magnetic fields;

sensing, by at least one sensor circuit of the plurality of sensor circuits, the modulated electrical characteristic of the antenna circuit when the antenna circuit couples to the at least one sensor circuit via one of the plurality of magnetic fields; and

determining alignment information of the vehicle based on the sensed modulated electrical characteristic.

29. The medium of claim 28 , wherein sensing the modulated electrical characteristic comprises sensing a modulated or varied impedance of the antenna circuit.

30. The medium of claim 28 , further comprising:

sensing a distinctive modulation pattern based on a distinct change of the disturbance in a magnetic field of the at least one sensor circuit in response to a degree of coupling to the antenna circuit, wherein the modulated electrical characteristic is modulated based on the distinct modulation pattern; and

uniquely identifying the antenna circuit based on the sensed distinct modulation pattern.