DEVICE AND METHOD FOR CONTACTLESS POWER TRANSFER

A wireless power transfer device (1) includes a power-supplying circuit (13) that supplies power to be transferred between a power-transmitting coil (L1) and a power receiving coil (L2) with at least one of the relative position and orientation between the coils being changeable, a displacement measuring section (14) that measures the amount of any changes in the relative position and orientation between the coils, a control section (15) that based on the result of measurements taken by the displacement measuring section (14), determines a frequency at which the efficiency of power transfer between the coils is maximized, and controls the power-supplying circuit (13) so that power having the frequency is transferred between the coils. The present invention provides a wireless power transfer device and method which can efficiently transfer power in a wireless manner if the relative position between the coils changes.