Foreign-object detecting device, wireless electric-power transmitting device, and wireless electric-power transmission system
First Claim
1. A foreign-object detecting device, comprising:
- a first coil having a first conducting wire that is wound in a winding direction and that has two terminals, one of the two terminals being an outside terminal of the first coil and the other terminal being an inside terminal of the first coil;
a second coil arranged symmetrically adjacent to the first coil and having a second conducting wire that is wound in a direction opposite to the winding direction of the first coil and that has two terminals, one of the terminals being an outside terminal of the second coil and the other terminal being an inside terminal of the second coil; and
foreign-object detecting circuitry operative to;
i) output a detection signal having a predetermined waveform to the outside terminal of the first coil and the outside terminal of the second coil or ii) output the same detection signal to the inside terminal of the first coil and the inside terminal of the second coil;
cause the detection signal to flow clockwise into one of the first coil and the second coil and cause the detection signal to flow counterclockwise to the other of the first coil and the second coil, to generate a combined magnetic field across a center of the first coil and a center of the second coil;
measure an amount of change in an impedance value of one of the first coil and the second coil, the amount of change corresponding to a change in the combined magnetic field which is caused by the presence or absence of a foreign object within the combined magnetic field across the center of the first coil and the center of the second coil; and
determine that a foreign object is present within the combined magnetic field across the center of the first coil and the center of the second coil, when the amount of change in the impedance value exceeds a predetermined value.
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Accused Products
Abstract
A foreign-object detecting device includes a first coil, a second coil arranged adjacent to the first coil and having the same winding direction as that of the first coil, and foreign-object detecting circuitry. The foreign-object detecting circuitry outputs a first detection signal to an outside or inside terminal of the first coil, outputs a second detection signal having an inverted phase to an outside or inside terminal of the second coil, causes one of the first and second detection signal to flow clockwise, causes the other detection signal to flow counterclockwise to generate a combined magnetic field across a center of the first and a center of the second coil, measures an amount of change in an impedance value of the first or second coils, and determines that a foreign object is present within the combined magnetic field, based on the amount of change.
15 Citations
22 Claims
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1. A foreign-object detecting device, comprising:
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a first coil having a first conducting wire that is wound in a winding direction and that has two terminals, one of the two terminals being an outside terminal of the first coil and the other terminal being an inside terminal of the first coil; a second coil arranged symmetrically adjacent to the first coil and having a second conducting wire that is wound in a direction opposite to the winding direction of the first coil and that has two terminals, one of the terminals being an outside terminal of the second coil and the other terminal being an inside terminal of the second coil; and foreign-object detecting circuitry operative to; i) output a detection signal having a predetermined waveform to the outside terminal of the first coil and the outside terminal of the second coil or ii) output the same detection signal to the inside terminal of the first coil and the inside terminal of the second coil; cause the detection signal to flow clockwise into one of the first coil and the second coil and cause the detection signal to flow counterclockwise to the other of the first coil and the second coil, to generate a combined magnetic field across a center of the first coil and a center of the second coil; measure an amount of change in an impedance value of one of the first coil and the second coil, the amount of change corresponding to a change in the combined magnetic field which is caused by the presence or absence of a foreign object within the combined magnetic field across the center of the first coil and the center of the second coil; and determine that a foreign object is present within the combined magnetic field across the center of the first coil and the center of the second coil, when the amount of change in the impedance value exceeds a predetermined value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A foreign-object detecting device, comprising:
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a first coil having a first conducting wire that is wound in a rectangular shape in a winding direction and that has two terminals, one of the two terminals being an outside terminal of the first coil and the other terminal being an inside terminal of the first coil; a second coil arranged symmetrically adjacent to the first coil and having a second conducting wire that is wound in a rectangular shape in a direction opposite to the winding direction of the first coil and that has two terminals, one of the terminals being an outside terminal of the second coil and the other terminal being an inside terminal of the second coil; and foreign-object detecting circuitry operative to; i) output a detection signal having a predetermined waveform to the outside terminal of the first coil and the outside terminal of the second coil or ii) output the same detection signal to the inside terminal of the first coil and the inside terminal of the second coil; cause the detection signal to flow clockwise into one of the first coil and the second coil and cause the detection signal to flow counterclockwise to the other of the first coil and the second coil, to generate a combined magnetic field across a center of the first coil and a center of the second coil; measure an amount of change in an impedance value of one of the first coil and the second coil, the amount of change corresponding to a change in the combined magnetic field which is caused by the presence or absence of a foreign object within the combined magnetic field across the center of the first coil and the center of the second coil; and determine that a foreign object is present within the combined magnetic field across the center of the first coil and the center of the second coil, when the amount of change in the impedance value exceeds a predetermined value. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A foreign-object detecting device, comprising:
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a first coil having a conducting wire that is wound; a second coil arranged symmetrically adjacent to the first coil and having a conducting wire that is wound; and foreign-object detecting circuitry operative to; output a first detection signal having a first predetermined waveform to the first coil and output a second detection signal having a second predetermined waveform to the second coil; cause the first detection signal to flow clockwise into one of the first coil and the second coil and cause the second detection signal to flow counterclockwise into the other of the first coil and the second coil, to generate a combined magnetic field across a center of the first coil and a center of the second coil; measure an amount of change in an impedance value of one of the first coil and the second coil, the amount of change corresponding to a change in the combined magnetic field which is caused by the presence or absence of a foreign object within the combined magnetic field across the center of the first coil and the center of the second coil; and determine that a foreign object is present within the combined magnetic field across the center of the first coil and the center of the second coil, when the amount of change in the impedance value exceeds a predetermined value.
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22. A foreign-object detecting device, comprising:
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a first coil having a conducting wire that is wound in a rectangular shape; a second coil arranged symmetrically adjacent to the first coil and having a conducting wire that is wound in a rectangular shape; and foreign-object detecting circuitry operative to; output a first detection signal having a first predetermined waveform to the first coil and output a second detection signal having a second predetermined waveform to the second coil; cause the first detection signal to flow clockwise into one of the first coil and the second coil and cause the second detection signal to flow counterclockwise into the other of the first coil and the second coil, to generate a combined magnetic field across a center of the first coil and a center of the second coil; measure an amount of change in an impedance value of one of the first coil and the second coil, the amount of change corresponding to a change in the combined magnetic field which is caused by the presence or absence of a foreign object within the combined magnetic field across the center of the first coil and the center of the second coil; and determine that a foreign object is present within the combined magnetic field across the center of the first coil and the center of the second coil, when the amount of change in the impedance value exceeds a predetermined value.
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Specification