Wireless power feeder, wireless power receiver, and wireless power transmission system
First Claim
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1. A wireless power feeder for feeding power from a feeding coil to a receiving coil, comprising:
- a power transmission control circuit that feeds AC power to the feeding coil at a drive frequency;
a feeding coil circuit that includes the feeding coil and a capacitor and resonates at a resonance frequency of the receiving coil;
a phase detection circuit that detects a phase difference between the voltage phase and current phase of the AC power; and
a signal receiving circuit that receives an output signal indicating the magnitude of an output from a power receiving side of the AC power, wherein the power transmission control circuit adjusts the drive frequency so as to reduce the phase difference to make the drive frequency track the resonance frequency, and the phase detection circuit performs ex-post adjustment of the detected value of one or both of the voltage and current phases according to the output signal.
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Abstract
Power is fed from a feeding coil L2 to a receiving coil L3 by magnetic resonance. A VCO 202 alternately turns ON/OFF switching transistors Q1 and Q2 at a drive frequency fo, whereby AC power is fed to the feeding coil L2, and then the AC power is fed from the feeding coil L2 to the receiving coil L3. A phase detection circuit 114 detects a phase difference between the current phase and voltage phase, and the VCO 202 adjusts the drive frequency fo such that the phase difference becomes zero. When load voltage is changed, the detected current phase value is adjusted with the result that the drive frequency fo is adjusted.
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Citations
13 Claims
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1. A wireless power feeder for feeding power from a feeding coil to a receiving coil, comprising:
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a power transmission control circuit that feeds AC power to the feeding coil at a drive frequency; a feeding coil circuit that includes the feeding coil and a capacitor and resonates at a resonance frequency of the receiving coil; a phase detection circuit that detects a phase difference between the voltage phase and current phase of the AC power; and a signal receiving circuit that receives an output signal indicating the magnitude of an output from a power receiving side of the AC power, wherein the power transmission control circuit adjusts the drive frequency so as to reduce the phase difference to make the drive frequency track the resonance frequency, and the phase detection circuit performs ex-post adjustment of the detected value of one or both of the voltage and current phases according to the output signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A wireless power transmission system for feeding power from a feeding coil to a receiving coil, comprising:
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a power transmission control circuit that feeds AC power to the feeding coil at a drive frequency; a feeding coil circuit that includes the feeding coil and a first capacitor; a receiving coil circuit that includes the receiving coil and a second capacitor; a loading circuit that includes a loading coil that is magnetically coupled to the receiving coil to receive the AC power from the receiving coil and a load that receives power from the loading coil; and a phase detection circuit that detects a phase difference between the voltage phase and current phase of the AC power, wherein the power transmission control circuit adjusts the drive frequency so as to reduce the phase difference, and the phase detection circuit performs ex-post adjustment of the detected value of one or both of the voltage and current phases according to the magnitude of an output voltage to be applied to a part of the loading circuit.
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Specification