Methods of selectively activating antenna zones of a near-field charging pad to maximize wireless power delivered to a receiver

• US 10,476,312 B2
• Filed: 04/02/2018
• Issued: 11/12/2019
• Est. Priority Date: 12/12/2016
• Status: Active Grant

• Current Assignee: Energous Corporation
• Original Assignee: Energous Corporation
• Inventors: Johnston, Cesar, Jain, Deepak, Bosso, Brian
• Primary Examiner(s): Parihar, Suchin
• Application Number:
  US15/943,559
• Publication Number:
  US 20180262060A1
• Time in Patent Office: 589 Days
• Field of Search: 320108
• CPC Class Codes: H02J 50/20 using microwaves or radio frequency waves
• CPC Class Codes: H02J 50/23 characterised by the type of transmitting antennas, e.g. directional array antennas or Yagi antennas
• CPC Class Codes: H02J 50/40 using two or more transmitting or receiving devices H02J50/50 takes precedence
• CPC Class Codes: H02J 7/0042 characterised by the mechanical construction
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer
• CPC Class Codes: H04W 4/80 Services using short range communication, e.g. near-field communication [NFC], radio-frequency identification [RFID] or low energy communication
• CPC Class Codes: Y02B 40/00 Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers

Abstract

An example method includes detecting, via a wireless communication component of a near-field charging pad (pad), that a receiver is within a threshold distance of the pad. In response to the detecting, the method includes: determining whether the receiver has been placed on the pad. In accordance with determining that the receiver has been placed on the pad, the method includes: selectively transmitting, by respective antenna elements included in a plurality of antenna zones of the pad, respective test power transmission signals with a first set of transmission characteristics until a determination is made that a particular power-delivery parameter associated with transmission of a respective test power transmission signal by at least one particular antenna zone satisfies power-delivery criteria. Upon determining that the particular power-delivery parameter satisfies the power-delivery criteria, the method also includes: transmitting additional power transmission signals to the receiver using the at least one particular antenna 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, a wireless communication component, and a plurality of antenna zones that each respectively include at least one antenna element;

detecting, via the wireless communication component, that a wireless power receiver is within a threshold distance of the near-field charging pad;

in response to detecting that the wireless power receiver is within the threshold distance of the near-field charging pad, determining whether the wireless power receiver has been placed on the near-field charging pad;

in accordance with determining that the wireless power receiver has been placed on the near-field charging pad, selectively transmitting, by respective antenna elements included in the plurality of antenna zones, respective test power transmission signals with a first set of transmission characteristics until a determination is made that a particular power-delivery parameter associated with transmission of a respective test power transmission signal by at least one particular antenna zone of the plurality of antenna zones satisfies power-delivery criteria; and

upon determining, by the one or more processors, that the particular power-delivery parameter satisfies the power-delivery criteria, transmitting a plurality of additional power transmission signals to the wireless power receiver using the at least one particular antenna zone, wherein each additional power transmission signal of the plurality of additional power transmission signals is transmitted with a second set of transmission characteristics, distinct from the first set of transmission characteristics.

2. The method of claim 1, wherein determining whether the wireless power receiver has been placed on the surface of the near-field charging pad includes:

transmitting the test power transmission signals using each of the plurality of antenna zones;

monitoring an amount of reflected power at the near-field charging pad while transmitting the test power transmission signals; and

determining that the wireless power receiver has been placed on the near-field charging pad when the amount of reflected power satisfies a device detection threshold.

3. The method of claim 2, wherein the amount of reflected power is measured at each antenna zone of the plurality of antenna zones.

4. The method of claim 2, wherein the device detection threshold is established during a calibration process for the near-field charging pad.

5. The method of claim 4, wherein:

the device detection threshold is specific to a type of device that is coupled with the wireless power receiver, and

the device detection threshold is selected by the one or more processors after detecting the wireless power receiver in proximity to the near-field charging pad.

6. The method of claim 1, wherein:

selectively transmitting the respective test power transmission signals is performed using each antenna zone of the plurality of antenna zones; and

the method further comprises, at the near-field charging pad, before the determination is made that the power-delivery parameter associated with transmission of the respective test power transmission signal by the at least one particular antenna zone of the plurality of antenna zones satisfies the power-delivery criteria;

updating a respective power-delivery parameter associated with transmission of a respective test power transmission signal by each respective antenna zone based on the transmission by each antenna zone; and

selecting two or more antenna zones, including the at least one particular antenna zone, based on their associated respective power-delivery parameters, to transmit wireless power to the wireless power receiver.

7. The method of claim 6, further comprising, at the near-field charging pad:

using each of the two or more antenna zones to transmit additional test power transmission signals having the first set of transmission characteristics,

wherein the determination that the particular power-delivery parameter satisfies the power-delivery criteria includes determining that the particular power-delivery parameter indicates that the at least one particular antenna zone is more efficiently transmitting wireless power to the wireless power receiver as compared to other antenna zones of the two or more antenna zones.

8. The method of claim 7, wherein:

the determination that the particular power-delivery parameter satisfies the power-delivery criteria also includes determining that the particular power-delivery parameter indicates that a first threshold amount of power is transferred to the wireless power receiver by the at least one particular antenna zone, and

the at least one particular antenna zone is the only antenna zone of the two or more antenna zones having a respective power-delivery parameter that indicates that the first threshold amount of power is transferred to the wireless power receiver.

9. The method of claim 6, wherein:

the determination that the particular power-delivery parameter satisfies the power-delivery criteria also includes determining that (i) no antenna zone is transferring a first threshold amount of power to the wireless power receiver and (ii) an additional power-delivery parameter associated with an additional antenna zone of the two or more antenna zones satisfies the power-delivery criteria,

the particular power-delivery parameter indicates that a first amount of power transferred to the wireless power receiver by the at least one particular antenna zone is above a second threshold amount of power and below the first threshold amount of power, and

the additional power-delivery parameter indicates that a second amount of power transferred to the wireless power receiver by the additional antenna zone is above the second threshold amount of power and below the first threshold amount of power.

10. The method of claim 9, wherein both of the particular antenna group and the additional antenna group are used to simultaneously transmit the additional plurality of power transmission signals to provide power to the wireless power receiver.

11. The method of claim 1, wherein information used to determine the power-delivery parameter is provided to the near-field charging pad by the wireless power receiver via the wireless communication component of the near-field charging pad.

12. The method of claim 1, wherein the second set of transmission characteristics is determined by adjusting at least one characteristic in the first set of transmission characteristics to increase an amount of power that is transferred by the particular antenna group to the wireless power receiver.

13. The method of claim 12, wherein the at least one adjusted characteristic is a frequency or impedance value.

14. The method of claim 1, further comprising, at the near-field charging pad:

while transmitting the additional plurality of power transmission signals, adjusting at least one characteristic in the second set of transmission characteristics, based on information received from the wireless power receiver, that is used to determine a level of power that is wirelessly delivered to the wireless power receiver by the near-field charging pad.

15. The method of claim 1, wherein the one or more processors are a component of a single integrated circuit that is used to control operation of the near-field charging pad.

16. The method of claim 6, wherein each respective power-delivery parameter corresponds to an amount of power received by the wireless power receiver based on transmission of a respective test power transmission signal by a respective antenna group of the plurality of antenna groups.

17. The method of claim 1, further comprising, at the near-field charging pad:

before transmitting the test power transmission signals, determining that the wireless power receiver is authorized to receive wirelessly delivered power from the near-field charging pad.

18. The method of claim 1, wherein:

the test power transmission signals are radio frequency (RF) power transmission signals; and

the additional power transmission signals in the plurality of additional power transmission signals are RF power transmission signals.

19. A non-transitory computer-readable storage medium storing executable instructions that, when executed by a near-field charging pad with a wireless communication component, a plurality of antenna zones that each respectively include at least one antenna element, and one or more processors, cause the near-field charging pad to:

detect, via the wireless communication component, that a wireless power receiver is within a threshold distance of the near-field charging pad;

in response to detecting that the wireless power receiver is within the threshold distance of the near-field charging pad, determine whether the wireless power receiver has been placed on the near-field charging pad;

in accordance with determining that the wireless power receiver has been placed on the near-field charging pad, selectively transmit, by respective antenna elements included in the plurality of antenna zones, respective test power transmission signals with a first set of transmission characteristics until a determination is made that a particular power-delivery parameter associated with transmission of a respective test power transmission signal by at least one particular antenna zone of the plurality of antenna zones satisfies power-delivery criteria; and

upon determining, by the one or more processors, that the particular power-delivery parameter satisfies the power-delivery criteria, transmit a plurality of additional power transmission signals to the wireless power receiver using the at least one particular antenna zone, wherein each additional power transmission signal of the plurality of additional power transmission signals is transmitted with a second set of transmission characteristics, distinct from the first set of transmission characteristics.

20. A near-field charging pad, comprising:

a wireless communication component;

a plurality of antenna zones that each respectively includes at least one antenna element;

one or more processors; 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;

detecting, via the wireless communication component, that a wireless power receiver is within a threshold distance of the near-field charging pad;

in response to detecting that the wireless power receiver is within the threshold distance of the near-field charging pad, determining whether the wireless power receiver has been placed on the near-field charging pad;

in accordance with determining that the wireless power receiver has been placed on the near-field charging pad, selectively transmitting, by respective antenna elements included in the plurality of antenna zones, respective test power transmission signals with a first set of transmission characteristics until a determination is made that a particular power-delivery parameter associated with transmission of a respective test power transmission signal by at least one particular antenna zone of the plurality of antenna zones satisfies power-delivery criteria; and

upon determining, by the one or more processors, that the particular power-delivery parameter satisfies the power-delivery criteria, transmitting a plurality of additional power transmission signals to the wireless power receiver using the at least one particular antenna zone, wherein each additional power transmission signal of the plurality of additional power transmission signals is transmitted with a second set of transmission characteristics, distinct from the first set of transmission characteristics.