Power transmitting apparatus, power transmission system, and power transmission method

1. A power transmitting apparatus, comprising:

a power transmission or reception circuit;

a first coil connected to the power transmission or reception circuit through wires;

a plurality of resonance coils having respective, different diameters one of which is selectively coupled to the first coil through electromagnetic induction; and

a position control apparatus configured to control the positions of the resonance coils,

wherein the position control apparatus is configured to selectively align an axial direction of one of the resonance coils with an axial direction of the first coil and

is configured to place an axial direction of each of one or more resonance coils other than the noted one of the resonance coils in a direction perpendicular to the axial direction of the first coil.

2. The power transmitting apparatus as claimed in claim 1 , wherein each of the first coil and the resonance coils is a planar coil, and the position control apparatus is configured to selectively place the noted one of the resonance coils in a plane in which the first coil is disposed, and to place the one or more resonance coils other than the noted one of the resonance coils in a plane perpendicular to the plane in which the first coil is disposed.

3. The power transmitting apparatus as claimed in claim 1 , wherein each of the first coil and the resonance coils is a planar coil, which is rotated around a common rotation axis by the position control apparatus for positional control.

4. A power transmission system, comprising:

a power transmitting apparatus; and

a power receiving apparatus configured to receive power from the power transmitting apparatus via magnetic resonance,

wherein at least one of the power transmitting apparatus and the power receiving apparatus includes:

a power transmission or reception circuit;

a first coil connected to the power transmission or reception circuit through wires;

a plurality of resonance coils having respective, different diameters one of which is selectively coupled to the first coil through electromagnetic induction; and

a position control apparatus configured to control the positions of the resonance coils,

wherein the position control apparatus is configured to selectively align an axial direction of one of the resonance coils with an axial direction of the first coil and

is configured to place an axial direction of each of one or more resonance coils other than the noted one of the resonance coils in a direction perpendicular to the axial direction of the first coil.

5. The power transmission system as claimed in claim 4 , wherein the power transmission or reception circuit detects an amount of received power, and the noted one of the resonance coils is selected from the plurality of resonance coils in response to the detected amount of received power.

6. The power transmission system as claimed in claim 4 , wherein the power transmitting apparatus and the power receiving apparatus include respective wireless communication apparatuses for communication with each other, and data indicative of the detected amount of received power is transmitted through the wireless communication apparatuses from the power receiving apparatus to the power transmitting apparatus.

7. The power transmission system as claimed in claim 4 , wherein each of the first coil and the resonance coils is a planar coil, and the position control apparatus is configured to selectively place the noted one of the resonance coils in a plane in which the first coil is disposed, and to place the one or more resonance coils other than the noted one of the resonance coils in a plane perpendicular to the plane in which the first coil is disposed.

8. A power transmission method, comprising:

selecting one of a plurality of resonance coils having respective, different diameters;

aligning an axial direction of the selected one of the resonance coils with an axial direction of a first coil;

placing an axial direction of each of one or more resonance coils other than the selected one of the resonance coils in a direction perpendicular to the axial direction of the first coil;

supplying alternating-current power to the first coil through wire connections;

supplying alternating-current power from the first coil to the selected one of the resonance coils through electromagnetic induction; and

transmitting power from the selected one of the resonance coils to a resonance coil on a receiver side through magnetic resonance.