Power transmission apparatus and power transmission method
First Claim
1. A power transmission apparatus comprising:
- a primary coil connected to an AC source;
a primary resonance coil configured to receive power from the primary coil by electromagnetic induction;
a secondary resonance coil configured to receive power from the primary resonance coil by magnetic field resonance occurred between the primary resonance coil and the secondary resonance coil;
a secondary coil configured to receive power from the secondary resonance coil by electromagnetic induction;
a variable capacitor attached to the primary resonance coil;
a phase comparison section configured to output a phase difference between a phase of voltage which is supplied to the primary resonance coil and a phase of current which flows through the primary resonance coil;
a memory; and
a processor coupled to the memory and configured to perform a process including;
detecting a phase difference between the phase of the voltage and the phase of the current output from the phase comparison section; and
determining a coupling degree between the primary resonance coil and the secondary resonance coil based on a change degree of the phase difference relative to a change amount of capacitance upon changing the capacitance of the variable capacitor;
wherein the determining includes determining that the coupling degree between the primary resonance coil and the secondary resonance coil is less than or equal to a first coupling degree, when the change degree of the phase difference relative to the change amount of the capacitance upon increasing the capacitance of the variable capacitor indicates a delay which is greater than or equal to a first delay degree.
1 Assignment
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Accused Products
Abstract
A power transmission apparatus includes a primary coil connected to an AC source; a primary resonance coil configured to receive power from the primary coil; a secondary resonance coil configured to receive power from the primary resonance coil by magnetic field resonance occurred between the primary resonance coil and the secondary resonance coil; a secondary coil configured to receive power from the secondary resonance coil; a phase difference detector detect a phase difference between a phase of voltage supplied to the primary resonance coil and a phase of current flowing through the primary resonance coil; a variable capacitor provided on the primary resonance coil; and a determination part determining a coupling degree between the primary resonance coil and the secondary resonance coil based on a change degree of the phase difference relative to a change amount of capacitance when the capacitance of the variable capacitor changes.
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Citations
10 Claims
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1. A power transmission apparatus comprising:
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a primary coil connected to an AC source; a primary resonance coil configured to receive power from the primary coil by electromagnetic induction; a secondary resonance coil configured to receive power from the primary resonance coil by magnetic field resonance occurred between the primary resonance coil and the secondary resonance coil; a secondary coil configured to receive power from the secondary resonance coil by electromagnetic induction; a variable capacitor attached to the primary resonance coil; a phase comparison section configured to output a phase difference between a phase of voltage which is supplied to the primary resonance coil and a phase of current which flows through the primary resonance coil; a memory; and a processor coupled to the memory and configured to perform a process including; detecting a phase difference between the phase of the voltage and the phase of the current output from the phase comparison section; and determining a coupling degree between the primary resonance coil and the secondary resonance coil based on a change degree of the phase difference relative to a change amount of capacitance upon changing the capacitance of the variable capacitor; wherein the determining includes determining that the coupling degree between the primary resonance coil and the secondary resonance coil is less than or equal to a first coupling degree, when the change degree of the phase difference relative to the change amount of the capacitance upon increasing the capacitance of the variable capacitor indicates a delay which is greater than or equal to a first delay degree. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for transmitting power in a power transmission apparatus including a primary coil connected to an AC source, a primary resonance coil configured to receive power from the primary coil by electromagnetic induction, a secondary resonance coil configured to receive power from the primary resonance coil by magnetic field resonance occurred between the primary resonance coil and the secondary resonance coil, a secondary coil configured to receive power from the secondary resonance coil by electromagnetic induction, and a variable capacitor attached to the primary resonance coil, the method comprising:
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detecting a phase difference between a phase of voltage which is supplied to the primary resonance coil and a phase of current which flows through the primary resonance coil; and determining a coupling degree between the primary resonance coil and the secondary resonance coil based on a change degree of the phase difference relative to a change amount of capacitance upon changing the capacitance of the variable capacitor, wherein the determining includes determining that the coupling degree between the primary resonance coil and the secondary resonance coil is less than or equal to a first coupling degree, when the change degree of the phase difference relative to the change amount of the capacitance upon increasing the capacitance of the variable capacitor indicates a delay which is greater than or equal to a first delay degree.
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Specification