Apparatuses and related methods for detecting magnetic flux field characteristics with a wireless power transmitter

• US 10,132,650 B2
• Filed: 01/22/2015
• Issued: 11/20/2018
• Est. Priority Date: 01/22/2015
• Status: Active Grant

• Current Assignee: Integrated Device Technology Incorporated (Renesas Electronics Corporation)
• Original Assignee: Integrated Device Technology Incorporated (Renesas Electronics Corporation)
• Inventors: Mehas, Gustavo J., Wilson, David F., Smith, Nicholaus W.
• Primary Examiner(s): Gannon, Levi
• Application Number:
  US14/603,296
• Publication Number:
  US 20160218559A1
• Time in Patent Office: 1,398 Days
• Field of Search: 307104
• CPC Class Codes: G01D 5/20 by varying inductance, e.g. by a movable armature
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/60 responsive to the presence of foreign objects, e.g. detection of living beings
• CPC Class Codes: H02J 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

A wireless power transmitter may include a transmit coil configured to generate a wireless power signal for wireless power transfer, at least one secondary sensing coil configured to generate a signal responsive to a magnetic flux field generated during the wireless power transfer, and control logic configured to detect at least one condition of a wireless power transfer system responsive to detecting distortion in the magnetic flux field from the at least one signal received from the secondary sensing coil. A related method may include generating with a wireless power transmitter a wireless power signal, generating with a plurality of secondary sensing coils one or more signals responsive to a magnetic flux field generated during the wireless power transfer, and detecting at least one condition of a wireless power transfer system responsive to the one or more signals generated by the plurality of secondary sensing coils.

Claims

1. A wireless power transmitter, comprising:

a transmit coil configured to generate a wireless power signal for wireless power transfer to a wireless power receiver;

at least one secondary sensing coil positioned adjacent to, coplanar with, and positioned outside of the transmit coil and configured to generate a signal responsive to a magnetic flux field generated during the wireless power transfer; and

control logic operably coupled with the at least one secondary sensing coil, the control logic configured to detect a misalignment between the transmit coil and the wireless power receiver responsive to detecting distortion in the magnetic flux field from the signal received from the at least one secondary sensing coil.

2. The wireless power transmitter of claim 1, wherein the at least one secondary sensing coil includes a plurality of secondary sensing coils operably coupled with the control logic.

3. The wireless power transmitter of claim 2, wherein each secondary sensing coil of the plurality of secondary sensing coils is independently coupled to the control logic to provide individual signals thereto.

4. The wireless power transmitter of claim 2, wherein at least two secondary sensing coils of the plurality of secondary sensing coils are coupled together to a common input of the control logic.

5. The wireless power transmitter of claim 4, wherein the at least two secondary sensing coils are counter wound relative to each other.

6. The wireless power transmitter of claim 4, wherein the at least two secondary sensing coils are configured to sum their respective signals to provide to the common input of the control logic.

7. The wireless power transmitter of claim 4, wherein the at least two secondary sensing coils are configured to subtract their respective signals to provide to the common input of the control logic.

8. The wireless power transmitter of claim 2, wherein the plurality of secondary sensing coils are coupled around an outside periphery of the transmit coil.

9. The wireless power transmitter of claim 2, wherein the plurality of secondary sensing coils are positioned within an inner area of the transmit coil.

10. A wireless power enabled apparatus, comprising:

a wireless power transmitter including;

a transmit coil configured to generate a wireless power signal from an input signal;

a plurality of secondary sensing coils located in proximity of, adjacent to, coplanar with, and positioned outside of the transmit coil, each secondary sensing coil configured to generate a signal of a magnetic flux field generated during wireless power transfer to a wireless power receiver; and

control logic operably coupled with the plurality of secondary sensing coils, the control logic configured to detect a misalignment between the transmit coil and the wireless power receiver based, at least in part, on a measured combination of inputs from the signals generated by the plurality of secondary sensing coils.

11. The wireless power enabled apparatus of claim 10, wherein the plurality of secondary sensing coils include a first secondary sensing coil and a second secondary sensing coil located along a y-axis, and a third secondary sensing coil and a fourth secondary sensing coil located along an x-axis, wherein:

the first secondary sensing coil is located along the y-axis at a +Y location;

the second secondary sensing coil is located along the y-axis at a −

Y location;

the third secondary sensing coil is located along the x-axis at a +X location; and

the fourth secondary sensing coil is located along the x-axis at a −

X location.

12. The wireless power enabled apparatus of claim 10, wherein each secondary sensing coil of the plurality of secondary sensing coils include is configured as one of a single loop coil and a multiple loop coil.

13. The wireless power enabled apparatus of claim 10, wherein the control logic is further configured to detect a presence of a foreign object within the magnetic flux field.

14. The wireless power enabled apparatus of claim 10, wherein the control logic is further configured to determine an amount of misalignment based, at least in part, on a comparison of the measured combination of inputs with a plurality of reference measurement combinations stored in memory of the control logic.

15. The wireless power enabled apparatus of claim 13, wherein the control logic is further configured to determine the presence of the foreign object based, at least in part, on a comparison of the measured combination of inputs with alignment information stored in memory of the control logic.

16. A method of detecting a misalignment from a wireless power transmitter, the method comprising:

generating with the wireless power transmitter a wireless power signal for wireless power transfer to a wireless power receiver;

generating with a plurality of secondary sensing coils positioned adjacent to, outside of, and coplanar with a transmit coil of the wireless power transmitter, one or more signals responsive to a magnetic flux field generated during the wireless power transfer; and

detecting the misalignment of a wireless power transfer system responsive to the one or more signals generated by the plurality of secondary sensing coils.

17. The method of claim 16,

further including detecting a presence of a foreign object within the magnetic flux field detected by the plurality of secondary sensing coils.

18. The method of claim 17, further including sampling the one or more signals according to a sampling frequency.

19. The method of claim 17, further comprising at least one of:

notifying a user of the misalignment of the transmit coil and a receive coil; and

notifying the user of the presence of the foreign object.

20. The method of claim 17, further comprising at least one of:

reducing a power level for the wireless power signal responsive to a detection of misalignment of the transmit coil and a receive coil;

reducing the power level for the wireless power signal responsive to a detection of the presence of the foreign object within the magnetic flux field;

reducing a power level for the wireless power signal responsive to a detection of a rapid reduction of misalignment of the transmit coil and the receive coil;

increasing the power level for the wireless power signal responsive to a determination that the misalignment of the transmit coil and the receive coil has been reduced; and

increasing the power level for the wireless power signal responsive to a determination that the foreign object has been removed from the magnetic flux field.