Wireless power transmission system
A wireless power transmission system includes a power transmission device, which applies an alternating-current voltage to active and passive electrodes, and a power reception device, which supplies to a load a voltage induced in active and passive electrodes facing the active and passive electrodes of the power transmission device. The power transmission device includes a planar coil connected to the active and passive electrodes and the power reception device includes a planar coil connected to the active and passive electrodes. Magnetic flux generated by the planar coils link with each other causing the planar coils to be magnetic-field coupled with each other. Thus, a wireless power transmission system capable of efficiently transmitting power is provided.
1. A wireless power transmission system comprising:
a power transmission device including:
a first power-transmission-side electrode,
a second power-transmission-side electrode,
an oscillation circuit configured to apply an alternating-current voltage to the first and second power-transmission-side electrodes, and
a power-transmission-side coil having a first end connected to the first power-transmission-side electrode and a second end connected to the second power-transmission-side electrode; and
a power reception device including:
a first power-reception-side electrode positioned to face the first power-transmission-side electrode,
a second power-reception-side electrode positioned to face the second power-transmission-side electrode,
a power-reception-side circuit configured to supply to a load a voltage induced in the first and second power-reception-side electrodes by capacitive coupling when the first and second power-reception-side electrodes face the first and second power-transmission-side electrodes, respective, and
a power-reception-side coil having a first end connected to the first power-reception-side electrode and a second end connected to the second power-reception-side electrode,
wherein the power-transmission-side coil is magnetic-field coupled to the power-reception-side coil.
2. The wireless power transmission system according to claim 1 , wherein magnetic flux generated by the power-reception-side coil linked with the power-transmission-side coil and magnetic flux generated by the power-transmission-side coil linked with the power-reception-side coil causes the power-transmission-side coil and the power-reception-side coil to be magnetic-field coupled with each other.
3. The wireless power transmission system according to claim 1 , wherein coil winding axes of the power-transmission-side coil and the power-reception-side coil extend in the same direction.
4. The wireless power transmission system according to claim 3 , wherein each of the coil winding axes are wound such that a direction of a magnetic field generated by the power-transmission-side coil when a current flows from the second power-transmission-side electrode to the first power-transmission-side electrode via the power-transmission-side coil is in a same direction as a magnetic field generated by the power-reception-side coil when a current flows from the first power-reception-side electrode to the second power-reception-side electrode via the power-reception-side coil.
5. The wireless power transmission system according to claim 1 , wherein the power-transmission-side coil and the power-reception-side coil are planar coils configured to face each other with a gap therebetween.
6. The wireless power transmission system according to claim 1 ,
wherein the first power-transmission-side electrode, the second power-transmission-side electrode and the power-transmission-side coil are disposed along a same plane of the power transmission device, and
wherein the first power-reception-side electrode, the second power-reception-side electrode and the power-reception-side coil are disposed along a same plane of the power reception device.
7. The wireless power transmission system according to claim 1 ,
wherein the power-transmission-side coil surrounds the first power-transmission-side electrode and the second power-transmission-side electrode surrounds the power-transmission -side coil, and
wherein the power-reception-side coil surrounds the first power-reception-side electrode and the second power-reception-side electrode surrounds the power-reception-side coil.
8. The wireless power transmission system according to claim 7 , wherein the first power-transmission-side electrode and the first power-reception-side electrode each comprise a circular shape, and the second power-transmission-side electrode and the second power-reception-side electrode each comprise an annular shape.
9. The wireless power transmission system according to claim 1 ,
wherein the first and second power-transmission-side electrodes are disposed in the power transmission device so as to face each other with the power-transmission-side coil interposed therebetween, and
wherein the first and second power-reception-side electrodes are disposed in the power reception device so as to face each other with the power-reception-side coil interposed therebetween.
10. The wireless power transmission system according to claim 9 , wherein the first and second power-transmission-side electrodes and the first and second power-reception-side electrodes have a shape configured to suppress generation of eddy currents.
11. The wireless power transmission system according to claim 1 , wherein the power-transmission-side coil forms a parallel resonance circuit with a capacitance between the first power-transmission-side electrode and the second power-transmission-side electrode.
12. The wireless power transmission system according to claim 10 , wherein the power-reception-side coil forms a parallel resonance circuit with a capacitance between the first power-reception-side electrode and the second power-reception-side electrode.
13. A wireless power transmission system comprising:
a power transmission device including:
a first power-transmission-side electrode,
a second power-transmission-side electrode,
an oscillation circuit configured to apply an alternating-current voltage to the first and second power-transmission-side electrodes,
a first power-transmission-side coil coupled between the oscillation circuit and the first power-transmission-side electrode,
a second power-transmission-side coil coupled between the oscillation circuit and the second power-transmission-side electrode; and
a power reception device including:
a first power-reception-side electrode positioned to face the first power-transmission-side electrode,
a second power-reception-side electrode positioned to face the second power-transmission-side electrode,
a power-reception-side circuit configured to supply to a load a voltage induced in the first and second power-reception-side electrodes by capacitive coupling when the first and second power-reception-side electrodes face the first and second power-transmission-side electrodes, respective,
a first power-reception-side coil coupled between the first power-reception-side electrode and the load,
a second power-reception-side coil coupled between the second power-reception-side electrode and the load,
wherein the first and second power-transmission-side coils are magnetic-field coupled to the first and second power-reception-side coils.
14. The wireless power transmission system according to claim 13 , wherein magnetic flux generated by the first and second power-reception-side coils linked with the first and second power-transmission-side coils and magnetic flux generated by the first and second power-transmission-side coils linked with the power-reception-side coils causes the respective coils to be magnetic-field coupled with each other.
15. The wireless power transmission system according to claim 13 , wherein the first and second power-transmission-side electrodes and the first and second power-reception-side electrodes have a shape configured to suppress generation of eddy currents.
16. A power transmission device for wirelessly transmitting power to a power reception device including first and second power-reception-side electrodes and a power-reception-side coil coupled to the first and second power-reception-side electrodes, the power transmission device comprising:
a first power-transmission-side electrode configured to face the first power-reception-side electrode and to be capacitively coupled with the first power-reception-side electrode to induce a voltage therebetween when the power reception device is mounted on the power transmission device;
a second power-transmission-side electrode configured to face the second power-reception-side electrode and to be capacitively coupled with the second power-reception-side electrode to induce a voltage therebetween when the power reception device is mounted on the power transmission device;
an oscillation circuit configured to apply an alternating-current voltage to the first and second power-transmission-side electrodes; and
a power-transmission-side coil having a first end connected to the first power-transmission-side electrode and a second end connected to the second power-transmission-side electrode,
wherein the power-transmission-side coil is magnetic-field coupled to the power-reception-side coil of the power reception device when the power reception device is mounted on the power transmission device.
17. The power transmission device according to claim 16 , wherein magnetic flux generated by the power-reception-side coil linked with the power-transmission-side coil and magnetic flux generated by the power-transmission-side coil linked with the power-reception-side coil causes the power-transmission-side coil and the power-reception-side coil to be magnetic-field coupled with each other.
18. The power transmission device system according to claim 16 ,
wherein coil winding axes of the power-transmission-side coil and the power-reception-side coil extend in the same direction, and
wherein each of the coil winding axes are wound such that a direction of a magnetic field generated by the power-transmission-side coil when a current flows from the second power-transmission-side electrode to the first power-transmission-side electrode via the power-transmission-side coil is in a same direction as a magnetic field generated by the power-reception-side coil when a current flows from the first power-reception-side electrode to the second power-reception-side electrode via the power-reception-side coil.
19. The wireless power transmission system according to claim 16 , wherein the first power-transmission-side electrode, the second power-transmission-side electrode and the power-transmission-side coil are disposed along a same plane of the power transmission device.
20. The power transmission device according to claim 16 , wherein the power-transmission-side coil surrounds the first power-transmission-side electrode and the second power-transmission-side electrode surrounds the power-transmission-side coil.