Systems and methods for generating power waves in a wireless power transmission system

• US 10,778,041 B2
• Filed: 03/03/2016
• Issued: 09/15/2020
• Est. Priority Date: 09/16/2015
• Status: Active Grant

• Current Assignee: Energous Corporation
• Original Assignee: Energous Corporation
• Inventors: Leabman, Michael A.
• Primary Examiner(s): Isla, Richard
• Assistant Examiner(s): Torres Ruiz, Johali A
• Application Number:
  US15/059,898
• Publication Number:
  US 20170110888A1
• Time in Patent Office: 1,657 Days
• CPC Class Codes: G06V 40/10 Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
• CPC Class Codes: H02J 50/20 using microwaves or radio frequency waves
• 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: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
• CPC Class Codes: H02J 7/0029 with safety or protection devices or circuits
• CPC Class Codes: H02J 7/0047 with monitoring or indicating devices or circuits
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer
• CPC Class Codes: H04N 7/18 Closed-circuit television [CCTV] systems, i.e. systems in which the video signal is not broadcast
• CPC Class Codes: H04W 52/283 Power depending on the position of the mobile

Abstract

Embodiments disclosed herein may generate and transmit power waves that, as result of their physical waveform characteristics (e.g., frequency, amplitude, phase, gain, direction), converge at a predetermined location in a transmission field to generate a pocket of energy. Receivers associated with an electronic device being powered by the wireless charging system, may extract energy from these pockets of energy and then convert that energy into usable electric power for the electronic device associated with a receiver. The pockets of energy may manifest as a three-dimensional field (e.g., transmission field) where energy may be harvested by a receiver positioned within or nearby the pocket of energy.

Claims

1. A method of wireless power transmission system, the method comprising:

at a transmitter configured to wirelessly provide power to a plurality of receivers at different spatial locations within a radio frequency (RF) transmission field;

identifying, by the transmitter, (i) a first receiver located in a first spatial location of the RF transmission field serviced by the transmitter, and (ii) a second receiver, distinct from the first receiver, located in a second spatial location, different from the first spatial location, of the RF transmission field;

prior to transmitting, by the transmitter, one or more RF power waves that provide usable power to the first receiver or the second receiver;

determining, by the transmitter, (i) a first specific absorption rate (SAR) value for the first spatial location at which the first receiver is located, based on the location of the first spatial location relative to the transmitter, and (ii) a second SAR value for the second spatial location at which the second receiver is located, based on the location of the second spatial location relative to the transmitter;

determining, by the transmitter, whether the first SAR value for the first spatial location satisfies a pre-defined SAR value threshold; and

transmitting, by the transmitter, the one or more RF power waves to the first receiver'"'"'s location in accordance with a determination that the first SAR value for the first spatial location satisfies the pre-defined SAR value threshold, wherein the first receiver uses energy from the one or more RF power waves received by the first receiver to power an electronic device coupled to the first receiver.

2. The method according to claim 1, wherein:

the one or more RF power waves transmitted to the first receiver'"'"'s location have at least one shared characteristic;

the method further comprises;

determining, by the transmitter, whether the second SAR value for the second spatial location satisfies the SAR value threshold; and

the transmitter forgoes transmitting RF power waves having the at least one shared characteristic to the second receiver'"'"'s location in accordance with a determination that the second SAR value for the second spatial location fails to satisfy the pre-defined SAR value threshold.

3. The method according to claim 2, further comprising transmitting, by the transmitter, one or more additional RF power waves that converge destructively at the second receiver'"'"'s location in accordance with a determination that the second SAR value for the second spatial location does not satisfy the pre-defined SAR value threshold, wherein the one or more additional RF power waves converge destructively to form the one or more null spaces.

4. The method according to claim 1, wherein the pre-defined SAR value threshold is within a margin of error beyond 1.6 watts per kilogram (W/Kg).

5. The method according to claim 1, further comprising receiving, by the transmitter, location data about locations associated with the first and second receivers, wherein identifying the first and second receivers is performed based, at least in part, on the location data.

6. The method according to claim 1, wherein the transmitter comprises one or more antenna arrays, and wherein each of the one or more antenna arrays comprises one or more antennas.

7. A system for wireless power transmission, the system comprising:

one or more transmitters, each of the one or more transmitters configured to wirelessly provide power to a plurality of receivers at different spatial locations within a radio frequency (RF) transmission field comprising;

a microprocessor configured to;

identify (i) a first receiver located in a first spatial location of the RF transmission field serviced by the transmitter, and (ii) a second receiver, distinct from the first receiver, located in a second spatial location, different from the first spatial location, of the RF transmission field;

prior to transmitting one or more RF power waves that provide usable power to the first receiver or the second receiver;

determine (i) a first specific absorption rate (SAR) value for the first spatial location at which the first receiver is located, based on the location of the first spatial location relative to the transmitter, and (ii) a second SAR value for the second spatial location at which the second receiver is located, based on the location of the second spatial location relative to the transmitter, and

determine whether the first SAR value for the first spatial location satisfies a pre-defined SAR value threshold; and

one or more antenna arrays that comprise one or more antennas configured to transmit RF power waves to the first receiver'"'"'s location in accordance with a determination that the first SAR value for the first spatial location satisfies the pre-defined SAR value threshold, wherein the first receiver uses energy from the one or more RF power waves received by the first receiver to power an electronic device coupled to the first receiver.

8. The system of claim 7, wherein the pre-defined SAR value threshold is within a margin of error beyond 1.6 watts per kilogram (W/Kg).

9. The system of claim 7, wherein the RF power waves comprise chirp waves having a frequency that is continually being varied.

10. The system according to claim 7, wherein at least one antenna of the one or more transmitters is selected from the group consisting of a flat antenna, a patch antenna, and a dipole antenna, and wherein the height of the at least one antenna is from about ⅛

inches to about 1 inch, and wherein the width of at least one antenna is from about ⅛

inches to about 1 inch.

11. The system according to claim 7, wherein the one or more antennas of the one or more transmitters are configured to operate in independent frequencies that allow a multichannel operation of pocket-forming in at least one of a single array, a pair array, and a quad array.

12. The system of claim 7, wherein the microprocessor is configured to:

in accordance with determining that the first SAR value does not satisfy the pre-defined SAR value threshold, select;

(i) respective antennas from the one or more antenna arrays to create a desired spacing between the respective antennas and (ii) an output frequency of the RF power waves; and

transmit the one or more RF power waves via the selected respective antennas and using the selected output frequency to cause the one or more RF power waves to converge destructively to form a null space at or proximate to the first spatial location within the RF transmission field.

13. The system of claim 7, wherein the microprocessor is configured to:

determine whether the second SAR value of the plurality of SAR values satisfies the pre-defined SAR value threshold;

in accordance with determining that the second SAR value satisfies the pre-defined SAR value threshold, select;

(i) respective antennas from the one or more antenna arrays to create a desired spacing between the respective antennas and (ii) an output frequency of RF power waves; and

transmit additional RF power waves via the selected respective antennas and using the selected output frequency to cause the additional RF power waves to converge constructively to form a pocket of energy at the second spatial location within the RF transmission field.

14. A non-transitory computer-readable storage medium storing executable instructions that, when executed by a transmitter configured to wirelessly provide power to a plurality of receivers at different spatial locations within a radio frequency (RF) transmission field with at least one processor and an antenna array, cause the transmitter to:

identify (i) a first receiver located in a first spatial location of the RF transmission field serviced by the transmitter, and (ii) a second receiver, distinct from the first receiver, located in a second spatial location, different from the first spatial location, of the RF transmission field;

prior to transmitting one or more RF power waves that provide usable power to the first receiver or the second receiver;

determine (i) a first specific absorption rate (SAR) value for the first spatial location at which the first receiver is located, based on the location of the first spatial location relative to the transmitter, and (ii) a second SAR value for the second spatial location at which the second receiver is located, based on the location of the second spatial location relative to the transmitter;

determine whether the first SAR value for the first spatial location satisfies a pre-defined SAR value threshold; and

transmit, by the antenna array, the one or more RF power waves to the first receiver'"'"'s location in accordance with a determination that the first SAR value for the first spatial location satisfies the pre-defined SAR value threshold, wherein the first receiver uses energy from the one or more RF power waves received by the first receiver to power an electronic device coupled to the first receiver.

15. The non-transitory computer-readable storage medium of claim 14, wherein the one or more RF power waves converge constructively at the first receiver'"'"'s location.

16. The non-transitory computer-readable storage medium of claim 14, wherein the executable instruction, when executed by the transmitter, further cause the transmitter to:

transmit, by the antenna array, other RF power waves that converge destructively at the first receiver'"'"'s location in accordance with a determination that the first SAR value for the first spatial location does not satisfy the pre-defined SAR value threshold.

17. The non-transitory computer-readable storage medium of claim 14, wherein the executable instruction, when executed by the transmitter, further cause the transmitter to:

transmit an exploratory RF power wave that has a power level comparatively lower than a power level of the one or more RF power waves transmitted by the transmitter; and

receive a communication indicating receipt of the exploratory RF power wave from the first receiver, the communication including data that is used to determine characteristics of the exploratory RF power wave, wherein appropriate characteristics of the one or more RF power waves transmitted by the transmitter are determined based at least in part on the data that is used to determine characteristics of the exploratory RF power wave.