Systems and methods for detecting wireless power receivers and other objects at a near-field charging pad

• US 10,615,647 B2
• Filed: 07/25/2018
• Issued: 04/07/2020
• Est. Priority Date: 02/02/2018
• Status: Active Grant

• Current Assignee: Energous Corporation
• Original Assignee: Energous Corporation
• Inventors: Johnston, Cesar, Jain, Deepak, Heinke, Erik, Hosseini, Alister, Nicolson, Sean
• Primary Examiner(s): Henze-Gongola, David V
• Application Number:
  US16/045,637
• Publication Number:
  US 20190245389A1
• Time in Patent Office: 622 Days
• Field of Search: 320108, 307104
• CPC Class Codes: H02J 50/05 using capacitive coupling
• CPC Class Codes: H02J 50/20 using microwaves or radio frequency waves
• CPC Class Codes: H02J 50/402 the two or more transmitting or the two or more receiving devices being integrated in the same unit, e.g. power mats with several coils or antennas with several sub-antennas
• CPC Class Codes: H02J 50/60 responsive to the presence of foreign objects, e.g. detection of living beings
• 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: H04B 17/21 for calibration; for correcting measurements
• CPC Class Codes: H04B 17/24 with feedback of measurements to the transmitter
• CPC Class Codes: H04B 17/29 Performance testing
• CPC Class Codes: H04B 5/70 specially adapted for specific purposes

Abstract

An example method is performed at a near-field charging pad that includes a wireless communication component, and a plurality of power-transfer zones that each respectively include at least one power-transferring element and a signature-signal receiving circuit. The method includes: sending, by a respective power-transferring element included in a first power-transfer zone of the plurality of power-transfer zones, test power transmission signals with first values for a set of transmission characteristics. The method also includes: in conjunction with sending each of the power transmission signals: detecting, using the signature-signal receiving circuit, respective amounts of reflected power at the first power-transfer zone. The method further includes: based on the respective amounts of reflected power, determining whether (i) an authorized wireless power receiver and/or (ii) an object other than a wireless power receiver is present on a surface of the charging pad that is adjacent the first power-transfer zone.

Claims

1. A method of operating a near-field charging pad, comprising:

at a near-field charging pad that includes one or more processors and a plurality of power-transfer zones that each respectively includes at least one power-transferring element and a signature-signal receiving circuit, wherein the one or more processors of the near-field charging pad are in communication with a data source that includes predefined signature signals, the predefined signature signals including a first predefined signature signal that identifies a wireless power receiver, a second predefined signature signal that identifies an object other than a wireless power receiver, and a third predefined signature signal that identifies a combination of a wireless power receiver and an object other than a wireless power receiver;

sending, by a respective power-transferring element included in a first power-transfer zone of the plurality of power-transfer zones, a plurality of test radio-frequency (RF) power transmission signals with first values for a first set of transmission characteristics;

in conjunction with sending each of the plurality of test RF power transmission signals, detecting, using the signature-signal receiving circuit, respective amounts of reflected power at the first power-transfer zone, wherein the respective amounts of reflected power correspond to energy from the test RF power transmission signals of the plurality of test RF power transmission signals that was reflected outside of the near-field charging pad and returned to the first power-transfer zone;

generating, using the signature-signal-receiving circuit and based on variations in the respective amounts of reflected power, a signature signal;

comparing the signature signal with the predefined signature signals that each identify an object among a plurality of objects;

based at least in part on the comparison of the signature signal with the predefined signature signals, determining whether (i) an authorized wireless power receiver is present on a surface of the near-field charging pad that is adjacent to the first power-transfer zone and/or (ii) an object other than a wireless power receiver is present on the surface of the near-field charging pad that is adjacent to the first power-transfer zone.

2. The method of claim 1, further comprising:

in accordance with a determination that the authorized wireless power receiver is present on the surface;

transmitting, by the respective power-transferring element included in the first power-transfer zone, additional RF power transmission signals with second values for the first set of transmission characteristics.

3. The method of claim 2, wherein:

the comparison of the signature signal with the predefined signature signals indicates that an object other than a wireless power receiver is present between the authorized wireless power receiver and the surface, and

the method further comprises;

determining that the near-field charging pad is configured to send RF power transmission signals while an object other than a wireless power receiver is present on the near-field charging pad; and

after determining that the near-field charging pad is configured to send RF power transmission signals while an object other than a wireless power receiver is present on the near-field charging pad, sending the additional RF power transmission signals.

4. The method of claim 2, wherein the signature signal is conveyed to the signature-signal receiving circuit of the first power-transfer zone by encoding the signature signal using manipulations to an impedance value of the wireless power receiver, the manipulations to the impedance value causing the amounts of reflected power to vary at different points in time.

5. The method of claim 2, further comprising:

after sending the additional RF power transmission signals, receiving a data-communication signal from the wireless power receiver, the data-communication signal including information that allows the near-field charging pad to determine device-specific values for the first set of transmission characteristics; and

in response to receiving the data-communication signal, ceasing to send the additional RF power transmission signals and instead sending, via the respective power-transfer element included in the first power-transfer zone, further RF power transmission signals with the device-specific values for the first set of transmission characteristics.

6. The method of claim 2, wherein the first and second values for the first set of transmission characteristics are the same.

7. The method of claim 2, wherein the first and second values for the first set of transmission characteristics are different.

8. The method of claim 1, wherein:

the near-field charging pad includes a data-communication radio, and

the sending of the plurality of test RF power transmission signals is performed without receiving any signal via the data-communication radio.

9. The method of claim 8, wherein the sending of the plurality of test RF power transmission signals is performed upon expiration of a predefined time period.

10. The method of claim 1, further comprising:

in conjunction with the sending of the plurality of test RF power transmission signals, sending a respective plurality of test RF power transmission signals by respective power-transferring elements included in each power-transfer zone of the plurality of power-transfer zones;

detecting, using respective signature-signal receiving circuits included in each respective power-transfer zone of the plurality of power-transfer zones, respective amounts of reflected power at each of the plurality of power-transfer zones; and

determining, for each power-transfer zone of the plurality of power-transfer zones, whether (a) a wireless power receiver and/or (ii) an object other than a wireless power receiver is present at a respective surface adjacent to each of the plurality of power-transfer zones.

11. The method of claim 10, further comprising:

based on the respective amounts of reflected power detected at a second power-transfer zone of the plurality of power-transfer zones, determining that an object other than a wireless power receiver is present at the second power-transfer zone; and

in accordance with determining that the object other than a wireless power receiver is present at the second power-transfer zone, determining whether the near-field charging pad is configured to transmit wireless RF power while one or more objects are present on the near-field charging pad,

wherein the sending of additional RF power transmission signals is only performed after determining that the near-field charging pad is configured to send wireless RF power while one or more objects are present on the near-field charging pad.

12. The method of claim 1, wherein the data source is populated with the predefined signature signals during a configuration process in which each of a plurality of different wireless power receivers is placed on the near-field charging pad to allow the near-field charging pad to detect and then store a respective predefined signature signal for each of the plurality of different wireless power receivers.

13. The method of claim 12, wherein the configuration process also includes placing a plurality of different objects, which are not wireless power receivers, on the near-field charging pad to allow the near-field charging pad to detect and then store a respective predefined signature signal for each of the plurality of different objects.

14. The method of claim 1, wherein the wireless power receiver comprises a power-receiving element and a rectifier coupled to the power-receiving element for converting alternating current generated by receipt of RF power transmission signals to direct current, and the signal-generating circuit of the wireless power receiver comprises:

impedance-modification circuitry positioned at a direct current output port of the rectifier, the impedance-modification circuitry configured to modify an impedance at the wireless power receiver.

15. The method of claim 13, wherein the configuration process also includes placing a plurality of different combinations of the plurality of different wireless power receivers and the plurality of different objects on the near-field charging pad to allow the near-field charging pad to detect and then store a respective predefined signature signal for each combination of the plurality of different wireless power receivers and the plurality of different objects.

16. A non-transitory computer-readable storage medium storing executable instructions that, when executed by a near-field charging pad with a plurality of power-transfer zones that each respectively include at least one power-transferring element and a signature-signal receiving circuit, wherein one or more processors of the near-field charging pad are in communication with a data source that includes predefined signature signals, the predefined signature signals including a first predefined signature signal that identifies a wireless power receiver, a second predefined signature signal that identifies an object other than a wireless power receiver, and a third predefined signature signal that identifies a combination of a wireless power receiver and an object other than a wireless power receiver, and the one or more processors, cause the near-field charging pad to:

send, by a respective power-transferring element included in a first power-transfer zone of the plurality of power-transfer zones, a plurality of test radio-frequency (RF) power transmission signals with first values for a first set of transmission characteristics;

in conjunction with sending each of the plurality of test RF power transmission signals, detect, using the signature-signal receiving circuit, respective amounts of reflected power at the first power-transfer zone, wherein the respective amounts of reflected power correspond to energy from the test RF power transmission signals of the plurality of test RF power transmission signals that was reflected outside of the near-field charging pad and returned to the first power-transfer zone;

generate, using the signature-signal-receiving circuit and based on variations in the respective amounts of reflected power, a signature signal;

compare the signature signal with the predefined signature signals that each identify an object among a plurality of objects;

based at least in part on the comparison of the signature signal with the predefined signature signals, determine whether (i) an authorized wireless power receiver is present on a surface of the near-field charging pad that is adjacent to the first power-transfer zone and/or (ii) an object other than a wireless power receiver is present on the surface of the near-field charging pad that is adjacent to the first power-transfer zone.

17. The non-transitory computer-readable of claim 16, wherein the executable instructions, when executed, also cause the near-field charging pad to:

in accordance with a determination that the authorized wireless power receiver is present on the surface;

transmit, by the respective power-transferring element included in the first power-transfer zone, additional RF power transmission signals with second values for the first set of transmission characteristics.

18. The non-transitory computer-readable of claim 17, wherein:

the comparison of the signature signal with the predefined signature signals indicates that an object other than a wireless power receiver is present between the authorized wireless power receiver and the surface, and

the executable instructions, when executed, also cause the near-field charging pad to;

determine that the near-field charging pad is configured to send RF power transmission signals while an object other than a wireless power receiver is present on the near-field charging pad; and

after determining that the near-field charging pad is configured to send RF power transmission signals while an object other than a wireless power receiver is present on the near-field charging pad, send the additional RF power transmission signals.

19. The non-transitory computer-readable of claim 17, wherein the signature signal is conveyed to the signature-signal receiving circuit of the first power-transfer zone by encoding the signature signal using manipulations to an impedance value of the wireless power receiver, the manipulations to the impedance value causing the amounts of reflected power to vary at different points in time.

20. The non-transitory computer-readable of claim 17, wherein the executable instructions, when executed, also cause the near-field charging pad to:

after sending the additional RF power transmission signals, receive a data-communication signal from the wireless power receiver, the data-communication signal including information that allows the near-field charging pad to determine device-specific values for the first set of transmission characteristics; and

in response to receiving the data-communication signal, cease sending the additional RF power transmission signals and instead sending, via the respective power-transfer element included in the first power-transfer zone, further RF power transmission signals with the device-specific values for the first set of transmission characteristics.

21. The non-transitory computer-readable of claim 17, wherein the first and second values for the first set of transmission characteristics are the same.

22. The non-transitory computer-readable of claim 17, wherein the first and second values for the first set of transmission characteristics are different.

23. The non-transitory computer-readable of claim 16, wherein:

the near-field charging pad includes a data-communication radio, and

the executable instructions that cause the near-field charging pad to send the plurality of test RF power transmission signals are performed without receiving any signal via the data-communication radio.

24. The non-transitory computer-readable of claim 23, wherein the executable instructions that cause the near-field charging pad to send the plurality of test RF power transmission signals are performed upon expiration of a predefined time period.

25. The non-transitory computer-readable of claim 16, wherein the executable instructions, when executed, also cause the near-field charging pad to:

in conjunction with the sending of the plurality of test RF power transmission signals, send a respective plurality of test RF power transmission signals by respective power-transferring elements included in each power-transfer zone of the plurality of power-transfer zones;

detect, using respective signature-signal receiving circuits included in each respective power-transfer zone of the plurality of power-transfer zones, respective amounts of reflected power at each of the plurality of power-transfer zones; and

determine, for each power-transfer zone of the plurality of power-transfer zones, whether (a) a wireless power receiver and/or (ii) an object other than a wireless power receiver is present at a respective surface adjacent to each of the plurality of power-transfer zones.

26. The non-transitory computer-readable of claim 25, wherein the executable instructions, when executed, also cause the near-field charging pad to:

based on the respective amounts of reflected power detected at a second power-transfer zone of the plurality of power-transfer zones, determine that an object other than a wireless power receiver is present at the second power-transfer zone; and

in accordance with determining that the object other than a wireless power receiver is present at the second power-transfer zone, determine whether the near-field charging pad is configured to transmit wireless RF power while one or more objects are present on the near-field charging pad,

wherein the sending of additional RF power transmission signals is only performed after determining that the near-field charging pad is configured to send wireless RF power while one or more objects are present on the near-field charging pad.

27. The non-transitory computer-readable of claim 16, wherein the data source is populated with the predefined signature signals during a configuration process in which each of a plurality of different wireless power receivers is placed on the near-field charging pad to allow the near-field charging pad to detect and then store a respective predefined signature signal for each of the plurality of different wireless power receivers.

28. The non-transitory computer-readable of claim 27, wherein the configuration process also includes placing a plurality of different objects, which are not wireless power receivers, on the near-field charging pad to allow the near-field charging pad to detect and then store a respective predefined signature signal for each of the plurality of different objects.

29. The non-transitory computer-readable of claim 28, wherein the configuration process also includes placing a plurality of different combinations of the plurality of different wireless power receivers and the plurality of different objects on the near-field charging pad to allow the near-field charging pad to detect and then store a respective predefined signature signal for each combination of the plurality of different wireless power receivers and the plurality of different objects.

30. The non-transitory computer-readable of claim 16, wherein the wireless power receiver comprises a power-receiving element and a rectifier coupled to the power-receiving element for converting alternating current generated by receipt of RF power transmission signals to direct current, and the signal-generating circuit of the wireless power receiver comprises:

impedance-modification circuitry positioned at a direct current output port of the rectifier, the impedance-modification circuitry configured to modify an impedance at the wireless power receiver.

31. A near-field charging pad, comprising:

a signature-signal receiving circuit;

a plurality of power-transfer zones that each respectively include at least one power-transferring element;

one or more processors, wherein the one or more processors of the near-field charging pad are in communication with a data source that includes predefined signature signals, the predefined signature signals including a first predefined signature signal that identifies a wireless power receiver, a second predefined signature signal that identifies an object other than a wireless power receiver, and a third predefined signature signal that identifies a combination of a wireless power receiver and an object other than a wireless power receiver; and

memory storing one or more programs that are configured for execution by the one or more processors, the one or more programs including instructions for;

sending, by a respective power-transferring element included in a first power-transfer zone of the plurality of power-transfer zones, a plurality of test radio-frequency (RF) power transmission signals with first values for a first set of transmission characteristics;

in conjunction with sending each of the plurality of test RF power transmission signals, detecting, using the signature-signal receiving circuit, respective amounts of reflected power at the first power-transfer zone, wherein the respective amounts of reflected power correspond to energy from the test RF power transmission signals of the plurality of test RF power transmission signals that was reflected outside of the near-field charging pad and returned to the first power-transfer zone;

generating, using the signature-signal-receiving circuit and based on variations in the respective amounts of reflected power, a signature signal;

comparing the signature signal with the predefined signature signals that each identify an object among a plurality of objects;

based at least in part on the comparison of the signature signal with the predefined signature signals, determining whether (i) an authorized wireless power receiver is present on a surface of the near-field charging pad that is adjacent to the first power-transfer zone and/or (ii) an object other than a wireless power receiver is present on the surface of the near-field charging pad that is adjacent to the first power-transfer zone.

32. The near-field charging pad of claim 31, wherein the one or more programs include instructions for:

in accordance with a determination that the authorized wireless power receiver is present on the surface;

transmitting, by the respective power-transferring element included in the first power-transfer zone, additional RF power transmission signals with second values for the first set of transmission characteristics.

33. The near-field charging pad of claim 32, wherein:

the comparison of the signature signal with the predefined signature signals indicates that an object other than a wireless power receiver is present between the authorized wireless power receiver and the surface, and

the one or more programs include instructions for;

determining that the near-field charging pad is configured to send RF power transmission signals while an object other than a wireless power receiver is present on the near-field charging pad; and

after determining that the near-field charging pad is configured to send RF power transmission signals while an object other than a wireless power receiver is present on the near-field charging pad, sending the additional RF power transmission signals.

34. The near-field charging pad of claim 32, wherein the signature signal is conveyed to the signature-signal receiving circuit of the first power-transfer zone by encoding the signature signal using manipulations to an impedance value of the wireless power receiver, the manipulations to the impedance value causing the amounts of reflected power to vary at different points in time.

35. The near-field charging pad of claim 32, wherein the one or more programs include instructions for:

after sending the additional RF power transmission signals, receiving a data-communication signal from the wireless power receiver, the data-communication signal including information that allows the near-field charging pad to determine device-specific values for the first set of transmission characteristics; and

in response to receiving the data-communication signal, ceasing to send the additional RF power transmission signals and instead sending, via the respective power-transfer element included in the first power-transfer zone, further RF power transmission signals with the device-specific values for the first set of transmission characteristics.

36. The near-field charging pad of claim 32, wherein the first and second values for the first set of transmission characteristics are the same.

37. The near-field charging pad of claim 32, wherein the first and second values for the first set of transmission characteristics are different.

38. The near-field charging pad of claim 31, wherein:

the near-field charging pad includes a data-communication radio, and

the instructions for the sending of the plurality of test RF power transmission signals are performed without receiving any signal via the data-communication radio.

39. The near-field charging pad of claim 38, wherein the instructions for the sending of the plurality of test RF power transmission signals are performed upon expiration of a predefined time period.

40. The near-field charging pad of claim 31, wherein the one or more programs include instructions for:

in conjunction with the sending of the plurality of test RF power transmission signals, sending a respective plurality of test RF power transmission signals by respective power-transferring elements included in each power-transfer zone of the plurality of power-transfer zones;

detecting, using respective signature-signal receiving circuits included in each respective power-transfer zone of the plurality of power-transfer zones, respective amounts of reflected power at each of the plurality of power-transfer zones; and

determining, for each power-transfer zone of the plurality of power-transfer zones, whether (a) a wireless power receiver and/or (ii) an object other than a wireless power receiver is present at a respective surface adjacent to each of the plurality of power-transfer zones.

41. The near-field charging pad of claim 40, wherein the one or more programs include instructions for:

based on the respective amounts of reflected power detected at a second power-transfer zone of the plurality of power-transfer zones, determining that an object other than a wireless power receiver is present at the second power-transfer zone; and

in accordance with determining that the object other than a wireless power receiver is present at the second power-transfer zone, determining whether the near-field charging pad is configured to transmit wireless RF power while one or more objects are present on the near-field charging pad,

wherein the sending of additional RF power transmission signals is only performed after determining that the near-field charging pad is configured to send wireless RF power while one or more objects are present on the near-field charging pad.

42. The near-field charging pad of claim 31, wherein the data source is populated with the predefined signature signals during a configuration process in which each of a plurality of different wireless power receivers is placed on the near-field charging pad to allow the near-field charging pad to detect and then store a respective predefined signature signal for each of the plurality of different wireless power receivers.

43. The near-field charging pad of claim 42, wherein the configuration process also includes placing a plurality of different objects, which are not wireless power receivers, on the near-field charging pad to allow the near-field charging pad to detect and then store a respective predefined signature signal for each of the plurality of different objects.

44. The near-field charging pad of claim 43, wherein the configuration process also includes placing a plurality of different combinations of the plurality of different wireless power receivers and the plurality of different objects on the near-field charging pad to allow the near-field charging pad to detect and then store a respective predefined signature signal for each combination of the plurality of different wireless power receivers and the plurality of different objects.

45. The near-field charging pad of claim 31, wherein the wireless power receiver comprises a power-receiving element and a rectifier coupled to the power-receiving element for converting alternating current generated by receipt of RF power transmission signals to direct current, and the signal-generating circuit of the wireless power receiver comprises:

impedance-modification circuitry positioned at a direct current output port of the rectifier, the impedance-modification circuitry configured to modify an impedance at the wireless power receiver.