Apparatus, system, and method for detecting a foreign object in an inductive wireless power transfer system via coupling coefficient measurement
First Claim
1. An inductive wireless power device, comprising:
- a transmitter configured to generate an electromagnetic field to a coupling region for wireless power transfer to a receiver;
a predefined coupling coefficient for the wireless power transfer; and
a control logic configured to determine a coupling coefficient of the wireless power transfer when the receiver is within the coupling region by detecting a change in a wireless power transfer characteristic caused by the receiver at a first time and a second time, and to determine a presence of a foreign object within the coupling region responsive to a comparison of the determined coupling coefficient and the predefined coupling coefficient for the wireless power transfer.
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Accused Products
Abstract
An inductive wireless power device comprises a transmitter configured to generate an electromagnetic field to a coupling region for wireless power transfer to a receiver, and control logic configured to determine a coupling coefficient of the wireless power transfer when the receiver is within the coupling region. The control logic also determines a presence of a foreign object within the coupling region responsive to a comparison of the determined coupling coefficient and an expected coupling coefficient for the wireless power transfer. An inductive wireless power device comprises a receiver configured to couple with an electromagnetic field in a coupling region for inductive wireless power transfer from a transmitter. The receiver is configured to alter a wireless power transfer characteristic of the transmitter for a determination of a presence of a foreign object within the coupling region responsive to a determination of a coupling coefficient of the wireless power transfer.
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Citations
24 Claims
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1. An inductive wireless power device, comprising:
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a transmitter configured to generate an electromagnetic field to a coupling region for wireless power transfer to a receiver; a predefined coupling coefficient for the wireless power transfer; and a control logic configured to determine a coupling coefficient of the wireless power transfer when the receiver is within the coupling region by detecting a change in a wireless power transfer characteristic caused by the receiver at a first time and a second time, and to determine a presence of a foreign object within the coupling region responsive to a comparison of the determined coupling coefficient and the predefined coupling coefficient for the wireless power transfer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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- 9. An inductive wireless power device, comprising a receiver configured to couple with an electromagnetic field in a coupling region for inductive wireless power transfer from a transmitter, wherein the receiver includes a receive coil configured to generate an AC signal responsive to coupling with the electromagnetic field, wherein the receiver is configured to alter a wireless power transfer characteristic of the transmitter by shorting the receive coil through a path parallel to the receiver coil at a first time, and to not short the receive coil at a second time, wherein shorting the receive coil through the path parallel to the receiver coil includes directly connecting across the receive coil.
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15. An inductive wireless power transfer system, comprising:
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a wireless power transmitting apparatus configured to generate an electromagnetic field in a coupling region for wireless power transfer; a predefined coupling coefficient for the wireless power transfer; and a wireless power receiving apparatus configured to couple with the electromagnetic field and generate an output signal in response thereto and to alter a wireless power transfer characteristic of the wireless power transmitting apparatus at a first time and a second time by shorting across a receive coil of the wireless power receiving apparatus at the first time and not shorting across the receive coil at the second time, wherein at least one of the wireless power transmitting apparatus and the wireless power receiving apparatus is configured to determine a coupling coefficient by a first comparison of the wireless power transfer characteristic at the first time and the second time, and determining the presence of a foreign object within the coupling region based, at least in part, on a second comparison of the coupling coefficient for the wireless power transfer between the wireless power transmitting apparatus and the wireless power receiving apparatus, and the predefined coupling coefficient for the wireless power transfer, wherein shorting across the receive coil includes directly connecting across the receive coil. - View Dependent Claims (16, 17, 18, 24)
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19. A method for detecting a foreign object in a coupling region of an inductive wireless power transfer system, the method comprising:
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determining a predefined coupling coefficient for the inductive wireless power transfer system; detecting a change in an inductive wireless power transfer characteristic of a transmitter caused by a receiver at a first time and a second time, wherein the receiver shorts across a receiver coil at the first time and provides no short across the receiver coil at the second time; determining a coupling coefficient for wireless power transfer between the transmitter and the receiver based on the change; and determining a presence of a foreign object based, at least in part, on a comparison of the determined coupling coefficient and the predefined coupling coefficient. - View Dependent Claims (20, 21)
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22. A method for altering a wireless power transfer characteristic of a wireless power transmitter for a determination of a presence of a foreign object within a coupling region of a wireless power transfer system based on a first state of a wireless power transfer characteristic and a second state of the wireless power transfer characteristic, the method comprising:
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determining a predefined coupling coefficient for the inductive wireless power transfer system; shorting a receive coil of a receiver by directly connecting across the receive coil in a path parallel with the receive coil at a first time for a wireless power transmitter to determine a wireless power transfer characteristic in the first state; and operating the receive coil of the receiver in a non-shorted state for the wireless power transmitter to determine the wireless power transfer characteristic in the second state; determining a coupling coefficient for wireless power transfer between the transmitter and the receiver based at least on the first state of the wireless power transfer characteristic and the second state of the wireless power transfer characteristic; determining the presence of a foreign object based, at least in part, on a comparison of the determined coupling coefficient and the predefined coupling coefficient. - View Dependent Claims (23)
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Specification