COIL UNIT, NONCONTACT POWER RECEIVING DEVICE, NONCONTACT POWER FEEDING DEVICE, NONCONTACT POWER FEEDING SYSTEM, AND VEHICLE

摘要

Disclosed is a noncontact power feeding system according to a resonance method, in which a power receiving device (110) is provided with plural secondary self-resonant coils (112 and 113). The noncontact power feeding system switches the secondary self-resonant coils (112 and 113) to detect a distance between the power receiving device (110) and a power feeding unit, and selects the secondary self-resonant coil of a high transmission efficiency in accordance with the detected distance (L), to thereby feed the power. Thus, the distance (L) between the power receiving device (110) and the power feeding unit can be precisely detected from the long to short ranges, and the transmission efficiency can be improved in the noncontact power transmission by the resonance method.