Device Handover

• US 20180159375A1
• Filed: 12/06/2016
• Published: 06/07/2018
• Est. Priority Date: 12/06/2016
• Status: Active Grant

• Current Assignee: X Development LLC (Alphabet Inc.)
• Original Assignee: X Development LLC (Alphabet Inc.)
• Inventors: Adolf, Brian, Grundmann, Michael, Liu, Eric
• Granted Patent: US 10,164,476 B2
• Time in Patent Office: Days
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/40 using two or more transmitting or receiving devices H02J50/50 takes precedence
• 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

Abstract

Described herein are methods and systems for facilitating a wireless power handover. In particular, a controller may cause a first transmitter to provide electrical power to a receiver. The controller may then determine that a handover condition is met and may responsively facilitate a handover to a second transmitter. During this handover, the controller may engage in a phase-determination process to determine first and second phases at which the first and second transmitters should respectively provide electrical power to the receiver. Once determined, the controller may then cause the first and second transmitters to respectively provide electrical power to the receiver at the first and second phases and at substantially the same time. Subsequently, the controller may cause the first transmitter to no longer provide electrical power to the receiver and the second transmitter to continue to provide electrical power to the receiver, thereby completing the handover.

Claims

1. A method comprising:

causing a first transmitter to provide electrical power to a receiver via a first wireless resonant coupling link using a first oscillation frequency;

determining that a handover condition is met; and

in response to determining that the handover condition is met, facilitating a handover to a second transmitter, wherein the handover comprises;

engaging in a phase-determination process to determine a first phase at which the first transmitter should provide electrical power to the receiver and a second phase at which the second transmitter should provide electrical power to the receiver;

causing the first transmitter to provide electrical power to the receiver at the determined first phase while also causing the second transmitter to provide electrical power to the receiver at the determined second phase, wherein the second transmitter provides electrical power to the receiver at the determined second phase via a second wireless resonant coupling link using a second oscillation frequency; and

after causing the first transmitter to provide electrical power to the receiver at the determined first phase while causing the second transmitter to provide electrical power to the receiver at the determined second phase, causing the first transmitter to no longer provide electrical power to the receiver and causing the second transmitter to continue to provide electrical power to the receiver.

2. The method of claim 1, wherein engaging in the phase-determination process to determine the first and second phases comprises determining the first and second phases that minimize destructive interference when causing the first transmitter to provide electrical power to the receiver while also causing the second transmitter to provide electrical power to the receiver.

3. The method of claim 1,

wherein engaging in the phase-determination process occurs while causing the first transmitter to provide electrical power to the receiver at a first power level and causing the second transmitter to provide electrical power to the receiver at a second power level that is lower than the first power level, and

wherein causing the second transmitter to continue to provide electrical power to the receiver comprises causing the second transmitter to continue to provide electrical power to the receiver at a third power level that is higher than the second power level.

4. The method of claim 1, wherein engaging in the phase-determination process comprises:

causing only the first transmitter to provide electrical power to the receiver during a first time period;

while causing only the first transmitter to provide electrical power to the receiver during the first time period, causing the receiver to determine a first-utilized phase at which the receiver receives electrical power from the first transmitter during the first time period;

causing only the second transmitter to provide electrical power to the receiver during a second time period that is different from the first time period;

while causing only the second transmitter to provide electrical power to the receiver during the second time period, causing the receiver to determine a second-utilized phase at which the receiver receives electrical power from the second transmitter during the second time period; and

based on a comparison of the determined first-utilized and second-utilized phases, determining the first phase at which the first transmitter should provide electrical power to the receiver and the second phase at which the second transmitter should provide electrical power to the receiver.

5. The method of claim 4, wherein determining, based on a comparison of the determined first-utilized and second-utilized phases, the first phase at which the first transmitter should provide electrical power to the receiver and the second phase at which the second transmitter should provide electrical power to the receiver comprises:

determining that the first-utilized phase is different from the second-utilized phase; and

in response to determining that the first-utilized phase is different from the second-utilized phase, determining that the first and second transmitters should both provide electrical power to the receiver at the first-utilized phase, and

wherein causing the first transmitter to provide electrical power to the receiver at the determined first phase while also causing the second transmitter to provide electrical power to the receiver at the determined second phase comprises causing the first transmitter to continue to provide electrical power to the receiver at the first-utilized phase and causing the second transmitter to also provide electrical power to the receiver at the first-utilized phase.

6. The method of claim 4, wherein determining, based on a comparison of the determined first-utilized and second-utilized phases, the first phase at which the first transmitter should provide electrical power to the receiver and the second phase at which the second transmitter should provide electrical power to the receiver comprises:

determining that the first-utilized phase is different from the second-utilized phase; and

in response to determining that the first-utilized phase is different from the second-utilized phase, determining that the first and second transmitters should both provide electrical power to the receiver at the second-utilized phase, and

wherein causing the first transmitter to provide electrical power to the receiver at the determined first phase while also causing the second transmitter to provide electrical power to the receiver at the determined second phase comprises causing the first transmitter to adjust transmission of electrical power to provide electrical power to the receiver at the second-utilized phase rather than at the first-utilized phase and causing the second transmitter to continue to provide electrical power to the receiver at the second-utilized phase.

7. The method of claim 4, wherein determining, based on a comparison of the determined first-utilized and second-utilized phases, the first phase at which the first transmitter should provide electrical power to the receiver and the second phase at which the second transmitter should provide electrical power to the receiver comprises:

determining that the first-utilized and second-utilized phases are the same matching phase; and

in response to determining that the first-utilized and second-utilized phases are the same matching phase, determining that the first and second transmitters should continue to provide electrical power to the receiver at the same matching phase, and

wherein causing the first transmitter to provide electrical power to the receiver at the determined first phase while also causing the second transmitter to provide electrical power to the receiver at the determined second phase comprises causing both the first and second transmitters to continue to provide electrical power to the receiver at the same matching phase.

8. The method of claim 1, further comprising:

before facilitating the handover, causing the receiver to determine a pre-handover phase at which the receiver receives electrical power from the first transmitter,

wherein engaging in the phase-determination process comprises determining that the second transmitter should also provide electrical power to the receiver at the determined pre-handover phase, and

wherein causing the first transmitter to provide electrical power to the receiver at the determined first phase while also causing the second transmitter to provide electrical power to the receiver at the determined second phase comprises causing both the first and second transmitters to respectively provide electrical power to the receiver at the determined pre-handover phase.

9. The method of claim 1, wherein engaging in the phase-determination process comprises:

determining information indicative of a position of the receiver relative to the first and second transmitters; and

based on the determined information indicative of the position of the receiver relative to the first and second transmitters, determining the first phase at which the first transmitter should provide electrical power to the receiver and the second phase at which the second transmitter should provide electrical power to the receiver.

10. The method of claim 9, wherein the first transmitter and the second transmitter are configured to engage in communications via a side-channel communication link, wherein determining information indicative of a position of the receiver relative to the first and second transmitters comprises causing the first and second transmitters to share via the side-channel communication link the information indicative of the position of the receiver relative to the first and second transmitters, and wherein determining the first and second phases is based on the shared information.

11. The method of claim 9, wherein the information indicative of the position of the receiver comprises at least one of the following:

a coupling factor of the first wireless resonant coupling link, a coupling factor of the second wireless resonant coupling link, a received signal strength of communications over a first side-channel communication link between the receiver and the first transmitter, a received signal strength of communications over a second side-channel communication link between the receiver and the second transmitter, a determined distance between the first transmitter and the receiver, a determined distance between the second transmitter and the receiver, or a reported Global Positioning System (GPS) location of the receiver.

12. The method of claim 1, wherein engaging in the phase-determination process comprises:

while causing the first transmitter to provide electrical power to the receiver, causing the second transmitter to carry out a phase sweep in which the second transmitter provides electrical power to the receiver at a plurality of phases over a particular time period;

causing the receiver to determine the highest total power level that the receiver receives over the particular time period;

determining a particular phase, from among the plurality of phases, at which the receiver receives electrical power from the second transmitter when the receiver receives the highest total power level; and

determining that the second transmitter should provide electrical power to the receiver at the determined particular phase,

wherein causing the second transmitter to provide electrical power to the receiver at the determined second phase comprises causing the second transmitter to provide electrical power to the receiver at the determined particular phase.

13. The method of claim 1, further comprising:

determining a coupling factor of the first wireless resonant coupling link,

wherein determining that the handover condition is met comprises determining that the coupling factor of the first wireless resonant coupling link is below a threshold coupling factor.

14. The method of claim 1, further comprising:

determining a distance between the first transmitter and the receiver,

wherein determining that the handover condition is met comprises determining that the distance between the first transmitter and the receiver is greater than a threshold distance.

15. The method of claim 1, further comprising:

determining a relative orientation between the first transmitter and the receiver,

wherein determining that the handover condition is met comprises determining that the relative orientation between the first transmitter and the receiver is greater than a threshold relative orientation.

16. The method of claim 1, further comprising:

determining a coupling factor of the second wireless resonant coupling link,

wherein determining that the handover condition is met comprises determining that the coupling factor of the second wireless resonant coupling link is above a threshold coupling factor.

17. The method of claim 1, further comprising:

determining a distance between the second transmitter and the receiver,

wherein determining that the handover condition is met comprises determining that the distance between the second transmitter and the receiver is less than a threshold distance.

18. The method of claim 1, further comprising:

determining a relative orientation between the second transmitter and the receiver,

wherein determining that the handover condition is met comprises determining that the relative orientation between the second transmitter and the receiver is less than a threshold relative orientation.

19. The method of claim 1, wherein the first transmitter comprises a first transmit resonator, wherein the first transmit resonator is coupled to a receive resonator of the receiver via the first wireless resonant coupling link, and wherein the first transmit resonator and the receive resonator are each configured to resonate at the first oscillation frequency.

20. The method of claim 1, wherein the second transmitter comprises a second transmit resonator, wherein the second transmit resonator is coupled to a receive resonator of the receiver via the second wireless resonant coupling link, and wherein the second transmit resonator and the receive resonator are each configured to resonate at the second oscillation frequency.

21. The method of claim 1, wherein the first and second oscillation frequencies are the same oscillation frequency.

22. A wireless power transmission system comprising:

a first transmitter;

a second transmitter; and

a controller configured to;

cause the first transmitter to provide electrical power to a receiver via a first wireless resonant coupling link using a first oscillation frequency;

determine that a handover condition is met; and

in response to determining that the handover condition is met, facilitate a handover to the second transmitter, wherein the handover comprises;

engaging in a phase-determination process to determine a first phase at which the first transmitter should provide electrical power to the receiver and a second phase at which the second transmitter should provide electrical power to the receiver;

causing the first transmitter to provide electrical power to the receiver at the determined first phase while also causing the second transmitter to provide electrical power to the receiver at the determined second phase, wherein the second transmitter provides electrical power to the receiver at the determined second phase via a second wireless resonant coupling link using a second oscillation frequency; and

after causing the first transmitter to provide electrical power to the receiver at the determined first phase while causing the second transmitter to provide electrical power to the receiver at the determined second phase, causing the first transmitter to no longer provide electrical power to the receiver and causing the second transmitter to continue to provide electrical power to the receiver.

23. A wireless power receiver comprising:

at least one receive resonator that is configured to resonate at one or more oscillation frequencies and that is operable to be coupled to one or more transmit resonators respectively via one or more wireless resonant coupling links;

one or more processors;

a non-transitory computer readable medium; and

program instructions stored on the non-transitory computer readable medium and executable by the one or more processors to;

cause the at least one receive resonator to receive electrical power from a first transmit resonator of a wireless power transmission system; and

engage in a phase-determination process during a handover of the at least one receive resonator to a second transmit resonator of the wireless power transmission system,

wherein the phase-determination process is to determine a first phase at which the first transmit resonator should provide electrical power to the at least one receive resonator during the handover and a second phase at which the second transmit resonator should provide electrical power to the at least one receive resonator during the handover,

wherein the at least one receive resonator no longer receives electrical power from the first transmit resonator after the handover, and

wherein the at least one receive resonator continues to receive electrical power from the second transmit resonator after the handover.