Methods And Systems For Detecting Foreign Objects In A Wireless Charging System
First Claim
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1. A wireless power charging system for charging a separate device having a power receiver coil, the wireless power charging system comprising:
- at least one power transmitter coil configured for transmitting power by inductive coupling to the power receiver coil in the separate device, the power transmitter coil characterized by a transmitter coil dimension that is a lateral dimension of the power transmitter coil; and
at least one foreign object detection (FOD) coil located proximate to the power transmitter coil and oriented to detect foreign objects that disturb the power transmission, the FOD coil characterized by a FOD coil dimension that is the lateral dimension of the FOD coil and that is smaller than the transmitter coil dimension.
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Abstract
Methods and systems are described for using detection coils to detect metallic or conductive foreign objects that can interfere with the wireless transfer of power from a power transmitter to a power receiver. In particular, the detection coils are targeted to foreign objects that are smaller than a power transmitter coil in the power transmitter.
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Citations
28 Claims
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1. A wireless power charging system for charging a separate device having a power receiver coil, the wireless power charging system comprising:
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at least one power transmitter coil configured for transmitting power by inductive coupling to the power receiver coil in the separate device, the power transmitter coil characterized by a transmitter coil dimension that is a lateral dimension of the power transmitter coil; and at least one foreign object detection (FOD) coil located proximate to the power transmitter coil and oriented to detect foreign objects that disturb the power transmission, the FOD coil characterized by a FOD coil dimension that is the lateral dimension of the FOD coil and that is smaller than the transmitter coil dimension. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A method for wireless power charging of a separate device having a power receiver coil, the method comprising:
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energizing a transmitter coil for transmitting power by inductive coupling to the receiver coil of the separate device; transmitting power from the transmitter coil to the receiver coil, the transmitted power pre-charging the receiver coil prior to using a foreign object detection (FOD) coil to detect a foreign object; suspending the transmission of power from the transmitter coil to the receiver coil; and energizing the FOD coil to identify foreign objects using power dissipation, the power dissipation in the receiver coil reduced by the pre-charging. - View Dependent Claims (26, 27, 28)
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Specification