Patent ID: 8258653

Claim:
A contactless power transmission system, comprising a power transmitting device including power transmission coils for transmitting power, and a power receiving device including a power receiving coil to be magnetically coupled to the power transmission coils, wherein the power transmitting device includes: a placing portion, on which the power receiving device is to be placed, a plurality of power transmission coils arranged below the placing portion, an oscillator for oscillating respective power transmission coils while separately exciting the power transmission coils, a detector for detecting inductances of the respective power transmission coils, and a determiner for determining a placed position of the power receiving device on the placing portion based on the inductances of the respective power transmission coils detected by the detector; and the oscillator specifies a plurality of power transmission coils to be oscillated based on the placed position determined by the determiner and sets parameters of currents to flow into the respective power transmission coils so as to mutually shift waveforms of the currents to flow into the plurality of specified power transmission coils, wherein the oscillator specifies the plurality of power transmission coils to be oscillated based on the placed position determined by the determiner and mutually shifts the phases of the currents to flow into the plurality of specified power transmission coils.