Detecting foreign objects in wireless power transfer systems
First Claim
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1. A method of performing foreign object detection in a wireless power transmission system, the method comprising:
- performing a plurality of FOD (Foreign Object Detection) measurements at different times;
determining whether the plurality of FOD measurements converge; and
when the plurality of FOD measurements converge, determining whether to enable or disable wireless power transfer based on one or more FOD measurements of the plurality of FOD measurements.
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Abstract
Methods, apparatus and computer-readable storage media for performing foreign object detection (FOD) in a wireless power transfer system. A plurality of FOD measurements may be performed and processed to perform FOD.
35 Citations
17 Claims
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1. A method of performing foreign object detection in a wireless power transmission system, the method comprising:
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performing a plurality of FOD (Foreign Object Detection) measurements at different times; determining whether the plurality of FOD measurements converge; and when the plurality of FOD measurements converge, determining whether to enable or disable wireless power transfer based on one or more FOD measurements of the plurality of FOD measurements. - View Dependent Claims (2, 3, 4, 5)
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6. An apparatus for performing foreign object detection, the apparatus comprising:
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circuitry configured to; perform a plurality of FOD (Foreign Object Detection) measurements at different times; determine whether the plurality of FOD measurements converge; and when the plurality of FOD measurements converge, determine whether to enable or disable wireless power transfer based on one or more FOD measurements of the plurality of FOD measurements. - View Dependent Claims (7, 8, 9, 10, 11)
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12. A method of performing foreign object detection in a wireless power transmission system having a wireless power transmitter and a wireless power receiver, the method comprising:
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receiving, by the wireless power transmitter, a reference value from the wireless power receiver, the reference value being a reference Q-factor or self-resonant frequency; the wireless power transmitter determining an expected Q-factor or self-resonant frequency for the wireless power transmitter-receiver pair based on the reference value and one or more characteristics of the wireless power transmitter; the wireless power transmitter setting a foreign object detection (FOD) threshold based on the expected Q-factor or self-resonant frequency for the wireless power transmitter-receiver pair; the wireless power transmitter performing an FOD measurement in the presence of the wireless power receiver to obtain an FOD measurement result; the wireless power transmitter determining whether to enable or disable wireless power transfer based on a comparison of the FOD measurement result and the FOD threshold; and the wireless power transmitter performing wireless power transfer to the wireless power receiver when the determination is made to enable wireless power transfer. - View Dependent Claims (13)
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14. An apparatus for performing foreign object detection in a wireless power transmission system having a wireless power transmitter and a wireless power receiver, the method comprising:
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circuitry configured to; receive a reference value from the wireless power receiver, the reference value being a reference Q-factor or self-resonant frequency; determine an expected Q-factor or self-resonant frequency for the wireless power transmitter-receiver pair based on the reference value and one or more characteristics of the wireless power transmitter; set a foreign object detection (FOD) threshold based on the expected Q-factor or self-resonant frequency for the wireless power transmitter-receiver pair; perform an FOD measurement in the presence of the wireless power receiver to obtain an FOD measurement result; determine whether to enable or disable wireless power transfer based on a comparison of the FOD measurement result and the FOD threshold; and perform wireless power transfer to the wireless power receiver when the determination is made to enable wireless power transfer. - View Dependent Claims (15)
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16. A method of performing foreign object detection (FOD) prior to initiating wireless power transfer from a wireless power transmitter to a wireless power receiver, the method comprising, by the wireless power transmitter:
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performing a first FOD measurement; determining whether the first FOD measurement is within a range for initiating wireless power transfer; making a first attempt to communicate with the wireless power receiver when the first FOD measurement is determined to be in range for initiating wireless power transfer, performing a second FOD measurement when the first attempt to communicate with the wireless power receiver is successful; determining whether the second FOD measurement is within a range for initiating wireless power transfer; making a second attempt to communicate with the wireless power receiver when the second FOD measurement is determined to be in a range for initiating wireless power transfer; and initiating wireless power transfer when the second attempt is successful.
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17. An apparatus for performing foreign object detection (FOD) prior to initiating wireless power transfer from a wireless power transmitter to a wireless power receiver, the apparatus comprising:
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circuitry configured to control the wireless power transmitter to; perform a first FOD measurement; determine whether the first FOD measurement is within a range for initiating wireless power transfer; make a first attempt to communicate with the wireless power receiver when the first FOD measurement is determined to be in range for initiating wireless power transfer, perform a second FOD measurement when the first attempt to communicate with the wireless power receiver is successful; determine whether the second FOD measurement is within a range for initiating wireless power transfer; make a second attempt to communicate with the wireless power receiver when the second FOD measurement is determined to be in a range for initiating wireless power transfer; and
initiate wireless power transfer when the second attempt is successful.
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Specification