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

Patent metadata

Field	Value
Publication number	US-11710987-B2
Application number	US-202016841612-A
Country	US
Kind code	B2
Filing date	Apr 6, 2020
Priority date	Feb 2, 2018
Publication date	Jul 25, 2023
Grant date	Jul 25, 2023

Abstract

An example method is performed at a near-field charging pad with a processor, a power-transferring element, a signature-signal-receiving circuit, and the processor of the near-field charging pad is in communication with a data source that includes predefined signature signals that each identify one of (i) a wireless power receiver, (ii) an object other than a wireless power receiver, and (iii) a combination of a wireless power receiver and an object other than a wireless power receiver. The method includes: after sending a plurality of test radio frequency (RF) power transmission signals, detecting, using the signature-signal-receiving circuit, respective amounts of reflected power; generating, based on variations in the respective amounts of reflected power, a signature signal; and determining whether (i) an authorized wireless power receiver is present on the near-field charging pad and/or (ii) an object other than a wireless power receiver is present on the near-field charging pad.

First claim

What is claimed is:

1. A method of operating a near-field charging pad, comprising:
at a near-field charging pad that includes one or more processors, a power-transferring element, 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, including (i) a first predefined signature signal that identifies a wireless power receiver, (ii) a second predefined signature signal that identifies an object other than a wireless power receiver, and (iii) a third predefined signature signal that identifies a combination of a wireless power receiver and an object other than a wireless power receiver:
after sending a plurality of test radio frequency (RF) power transmission signals using the power-transferring element, detecting, using the signature-signal-receiving circuit, respective amounts of reflected power that correspond to energy from the plurality of test RF power transmission signals that was reflected outside of the near-field charging pad and returned to the near-field charging pad;
generating, using the signature-signal-receiving circuit and based on variations in the respective amounts of reflected power, a new signature signal; and
based at least in part on comparing the new signature signal with the predefined signature signals, determining whether (i) an authorized wireless power receiver is present on the near-field charging pad and/or (ii) an object other than a wireless power receiver is present on the near-field charging pad.

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 power-transferring element, additional RF power transmission signals with values for a set of transmission characteristics, the values being distinct from values for the plurality of test RF power transmission signals.

3. The method of claim 2 , wherein:
the comparison of the new 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 a surface of the near-field charging pad, 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 new signature signal is conveyed to the signature-signal-receiving circuit by encoding the new 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 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 power-transfer element, further RF power transmission signals with the device-specific values for the set of transmission characteristics.

6. 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.

7. The method of claim 6 , wherein the sending of the plurality of test RF power transmission signals is performed upon expiration of a predefined time period.

8. 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 of a 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 (i) 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.

9. The method of claim 8 , further comprising:
based on the respective amounts of reflected power detected at a particular power-transfer zone of the plurality of power-transfer zones, determining that an object other than a wireless power receiver is present at the particular power-transfer zone; and
in accordance with determining that the object other than a wireless power receiver is present at the particular 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 transmit wireless RF power while one or more objects are present on the near-field charging pad.

10. 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.

11. The method of claim 10 , 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.

12. 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 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.

13. A non-transitory computer-readable storage medium storing executable instructions that, when executed by a near-field charging pad that includes one or more processors, a power-transferring element, 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, including (i) a first predefined signature signal that identifies a wireless power receiver, (ii) a second predefined signature signal that identifies an object other than a wireless power receiver, and (iii) a third predefined sign

Assignees

• Energous Corp

Inventors

• Johnston Cesar
• Jain Deepak
• Heinke Erik
• Hosseini Alister
• Nicolson Sean

Classifications

• H02J50/60 Primary

  responsive to the presence of foreign objects, e.g. detection of living beings · CPC title

• H02J50/05

  using capacitive coupling · CPC title

• H02J50/20

  using microwaves or radio frequency waves · CPC title

• H02J50/80

  involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices · CPC title

• H04B5/0025

  Electricity · mapped topic