POWER TRANSMISSION APPARATUS AND POWER RECEPTION APPARATUS FOR WIRELESS POWER TRANSFER AND WIRELESS POWER TRANSFER SYSTEM

摘要

A power transmission apparatus oscillates alternating current power at a first frequency (f1) which is lower than a resonant frequency (fr) of the second resonator and at a second frequency (f2) which is higher than the resonant frequency (fr). The power transmission apparatus measures an inductance value Lin (f1) and an inductance value Lin (f2). The inductance value Lin (f1) is measured when the oscillation circuit oscillates alternating current power at the first frequency (f1), and the inductance value Lin (f2) is measured when the oscillation circuit oscillates alternating current power at the second frequency (f2). The power transmission apparatus calculates a coupling coefficient k by using an expression represented by k²=1−Lin(f2)/Lin(f1), to detect relative position of the second resonator to the first resonator on the basis of the coupling coefficient k.