Abstract: A power receiving device that receives electric power output from a power transmission device includes a primary side coil and supplies electric power to a load according to the electric power. The power receiving device includes: an adjusting device that adjusts a value of a third current to be a predetermined value, the third current is generated from the second current and supplied to the load; a detecting device that detects the third current; and a variable capacitor coupled between the secondary side coil and the load. The variable capacitor ensures a changeable capacitance value. The adjusting device performs an adjustment based on a detection result by the detecting device. The variable capacitor is coupled in series with the secondary side coil and the load. The adjusting device includes a first adjusting device that increases the capacitance value and a second adjusting device that decreases the capacitance value.

Abstract: A power transmission device includes a power transmission circuit that includes a power transmission coil to transmit electric power to a power receiving coil of a power receiving device, a magnetic body that is magnetically coupled with the power transmission coil, and a moving device that changes a relative positional relationship between the magnetic body and the power transmission coil to change an impedance of the power transmission circuit such that the electric power is cut off or transmitted.

Abstract: A power transmission device includes a power transmission circuit, a third coil, and a turning device. The power transmission circuit includes a second coil that supplies a first coil of a power receiving device with electric power. The third coil is magnetically coupled with the second coil. The turning device causes the third coil to turn about a turning shaft that intersects with a winding shaft of the second coil, to change an impedance of the power transmission circuit such that the electric power is cut off or supplied.

Abstract: The present invention is a power feeding system that includes a power transmission device and a power receiving device. The power transmission device includes a primary side coil. The power receiving device includes a secondary side coil. The power receiving device side performs an adjustment such that a value of a current supplied to a load becomes a predetermined value. Thus, the present invention solves a problem of a conventional power feeding system that, for example, an increase in a current value supplied to a load possibly damages the load. The power receiving device receives electric power output from the power transmission device that includes a primary side coil. The power receiving device is configured to supply electric power according to the electric power to the load. The power receiving device includes a secondary side coil and an adjusting device. In the secondary side coil, a second current is generated according to a first current which is supplied to the primary side coil.