Wireless power feeder, wireless power receiver, and wireless power transmission system

摘要

Power is fed from a power feeding coil L2 to a power 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 supplied to the power feeding coil L2, and then the AC power is supplied from the power feeding coil L2 to the power receiving coil L3. A phase detection circuit 114 detects a phase difference between current and voltage phases, and the VCO 202 adjusts the drive frequency fo such that the phase difference becomes zero. When load voltage is changed, the detected voltage phase value is adjusted with the result that the drive frequency fo is adjusted.

主权项

1. A wireless power feeder that wirelessly feeds power from a power feeding coil to a power receiving coil using a magnetic field resonance phenomenon between the power feeding coil and the power receiving coil, the feeder comprising:
the power feeding coil; a power transmission control circuit that feeds AC power to the power feeding coil at a drive frequency so as to make the power feeding coil feed the AC power to the power receiving coil; a phase detection circuit that detects a phase difference between voltage and current phases of the AC power; a signal receiving coil that receives, from the AC power receiving side, an output signal having a duty ratio indicating an output level; and a signal adjustment circuit that DC-converts the output signal in accordance with the duty ratio, the power transmission control circuit adjusting the drive frequency so as to reduce the phase difference, the phase detection circuit performing ex-post adjustment of the detected value of one or both of the voltage and current phases in accordance with a signal level of the DC-converted output signal.