POWER TRANSMISSION SYSTEM AND POWER TRANSMISSION APPARATUS
First Claim
1. A power transmission system comprising:
- a power transmission apparatus having a power transmission coil to wirelessly transmit electric power;
a power receiving apparatus having a power receiving coil to wirelessly receive electric power from the power transmission apparatus; and
a foreign-substance detecting unit to detect a foreign substance which is present between the power transmission coil and the power receiving coil,whereinthe power transmission apparatus includes;
a voltage supply to be frequency-variable and capable of outputting a first AC signal;
a power supply controller to vary a frequency of the first AC signal in a frequency range from a first frequency to a second frequency;
the power transmission coil to resonate at a first resonance frequency and to generate a magnetic field by receiving the first AC signal; and
a first measurement unit to measure a first reflectance in the frequency range two or more times, the first reflectance being at least one of a voltage reflectance of the first AC signal, an AC reflectance of the first AC signal, and a power reflectance of the first AC signal;
whereinthe power receiving apparatus includes;
the power receiving coil to resonate at a second resonance frequency and to generate a second AC signal by receiving the magnetic field, the second AC signal being passed through a load; and
a second measurement unit to measure a second reflectance in the frequency range two or more times, the second reflectance being at least one of a voltage reflectance of the second AC signal, an AC reflectance of the second AC signal, and a power reflectance of the second AC signal; and
whereinthe foreign-substance detecting unit uses a first peaking frequency and a second peaking frequency to detect the foreign substance, the first peaking frequency being a frequency at which the first reflectance reaches a local minimum, the second peaking frequency being a frequency at which the second reflectance reaches a local minimum.
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Accused Products
Abstract
A power transmission system includes a power transmission apparatus, a power receiving apparatus, and a foreign-substance detecting unit. The power transmission apparatus has a power transmission coil to wirelessly transmit electric power. The power receiving apparatus has a power receiving coil to wirelessly receive electric power from the power transmission apparatus. The foreign-substance detecting unit detects a foreign substance which is present between the power transmission coil and the power receiving coil. In addition, the power transmission apparatus includes a voltage supply, a power supply controller, the power transmission coil, and a first measurement unit. The power receiving apparatus includes the power receiving coil and a second measurement unit.
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Citations
15 Claims
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1. A power transmission system comprising:
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a power transmission apparatus having a power transmission coil to wirelessly transmit electric power; a power receiving apparatus having a power receiving coil to wirelessly receive electric power from the power transmission apparatus; and a foreign-substance detecting unit to detect a foreign substance which is present between the power transmission coil and the power receiving coil, wherein the power transmission apparatus includes; a voltage supply to be frequency-variable and capable of outputting a first AC signal; a power supply controller to vary a frequency of the first AC signal in a frequency range from a first frequency to a second frequency; the power transmission coil to resonate at a first resonance frequency and to generate a magnetic field by receiving the first AC signal; and a first measurement unit to measure a first reflectance in the frequency range two or more times, the first reflectance being at least one of a voltage reflectance of the first AC signal, an AC reflectance of the first AC signal, and a power reflectance of the first AC signal; wherein the power receiving apparatus includes; the power receiving coil to resonate at a second resonance frequency and to generate a second AC signal by receiving the magnetic field, the second AC signal being passed through a load; and a second measurement unit to measure a second reflectance in the frequency range two or more times, the second reflectance being at least one of a voltage reflectance of the second AC signal, an AC reflectance of the second AC signal, and a power reflectance of the second AC signal; and wherein the foreign-substance detecting unit uses a first peaking frequency and a second peaking frequency to detect the foreign substance, the first peaking frequency being a frequency at which the first reflectance reaches a local minimum, the second peaking frequency being a frequency at which the second reflectance reaches a local minimum. - View Dependent Claims (4, 6, 8, 10, 12)
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2. A power transmission system comprising:
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a power transmission apparatus having a power transmission coil to wirelessly transmit electric power; a power receiving apparatus having a power receiving coil to wirelessly receive electric power from the power transmission apparatus; and a foreign-substance detecting unit to detect a foreign substance which is present between the power transmission coil and the power receiving coil, wherein the power transmission apparatus includes; a voltage supply to be frequency-variable and capable of outputting a first AC signal; a power supply controller to vary a frequency of the first AC signal in a frequency range from a first frequency to a second frequency; the power transmission coil to resonate at a first resonance frequency and to generate a magnetic field by receiving the first AC signal; a first measurement unit to measure a first reflectance and first power in the frequency range two or more times, the first reflectance being at least one of a voltage reflectance of the first AC signal, an AC reflectance of the first AC signal, and a power reflectance of the first AC signal, the first power being transmitted by the power transmission coil; wherein the power receiving apparatus includes; the power receiving coil to resonate at a second resonance frequency and to generate a second AC signal in response to the magnetic field; a second measurement unit to measure second power in the frequency range two or more times, the second power being supplied to a load; and wherein the foreign-substance detecting unit uses a first peaking frequency and a third peaking frequency to detect the foreign substance, the first peaking frequency being a frequency at which the first reflectance reaches a local minimum, the third peaking frequency being a frequency at which a power transmission efficiency reaches a local maximum, the power transmission efficiency being determined by the first electric power and the second electric power. - View Dependent Claims (3, 5, 7, 9, 11, 13)
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14. A power transmission apparatus using a transmission coil to wirelessly transmit electric power to a power receiving apparatus having a power receiving coil, comprising:
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a voltage supply to be frequency-variable and capable of outputting a first AC signal; a power supply controller to vary a frequency of the first AC signal in a frequency range from a first frequency to a second frequency; a power transmission coil to resonate at a first resonance frequency and to generate a magnetic field by receiving the first AC signal; a first measurement unit to measure a first reflectance in the frequency range two or more times, the first reflectance being at least one of a voltage reflectance of the first AC signal, an AC reflectance of the first AC signal, and a power reflectance of the first AC signal; a receiving unit to receive a piece of information of a second peaking frequency at which at least one of a voltage reflectance of a second AC signal, a current reflectance of the second AC signal, and a power reflectance of the second AC signal reaches a local minimum, the second AC signal being generated by the magnetic field via the power receiving coil, wherein a foreign substance between the power transmission coil and the power receiving coil is detected by the use of a first peaking frequency at which the first reflectance reaches a local minimum and the second peaking frequency.
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15. A power transmission apparatus using a transmission coil to wirelessly transmit electric power to a power receiving apparatus having a power receiving coil, comprising:
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a voltage supply to be frequency-variable and capable of outputting a first AC signal; a power supply controller to vary a frequency of the first AC signal in a frequency range from a first frequency to a second frequency; a power transmission coil to resonate at a first resonance frequency and to generate a magnetic field by receiving the first AC signal; a first measurement unit to measure a first reflectance and first electric power in the frequency range two or more times, the first reflectance being at least one of a voltage reflectance of the first AC signal, an AC reflectance of the first AC signal, and a power reflectance of the first AC signal, the first electric power being transmitted by the power transmission coil; a receiving unit to receive a piece of information of second electric power of a second AC signal to be generated by the magnetic field via the power receiving coil, wherein a foreign substance between the power transmission coil and the power receiving coil is detected by the use of a first peaking frequency at which the first reflectance reaches a local minimum and a third peaking frequency at which a power transmission efficiency reaches a local maximum, the power transmission efficiency being determined by the first electric power and the second electric power.
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Specification