Feeding system, feeding device and feeding method

摘要

PROBLEM TO BE SOLVED: To suppress the heat generation by a metal foreign substance.SOLUTION: A power feeding system 100 includes a power feeding device 1 and a power receiving device 2. The power is fed from the power feeding device 1 to the power receiving device 2 through the electromagnetic induction. The power receiving device 2 includes a resonance circuit 20 including: a power receiving coil 21 to which the power is fed from a power feeding coil 11; a resonance capacitor 22 that resonates with the power receiving coil 21; and a resonance control transistor 23 that controls the resonance state by changing the electric connection state of the resonance capacitor 22. The power feeding device 1 includes a peak value change detection unit 40 that detects the change in electric connection state of the resonance capacitor 22 as a periodical waveform change in the excitation voltage excited by the power feeding coil 11, and a driving control unit 50 that determines, if the peak value change detection unit 40 has not detected the periodical waveform change and the waveform of the excitation voltage has gone out of a predetermined range, a foreign substance exists in the power feeding coil 11.SELECTED DRAWING: Figure 1