WIRELESS POWER FEEDER AND WIRELESS POWER TRANSMISSION SYSTEM

• US 20120146424A1
• Filed: 02/01/2011
• Published: 06/14/2012
• Est. Priority Date: 12/14/2010
• Status: Abandoned Application

• Current Assignee: TDK Corporation
• Original Assignee: TDK Corporation
• Inventors: URANO, Takashi
• Application Number:
  US13/018,919
• Publication Number:
  US 20120146424A1
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/20 using microwaves or radio frequency waves
• CPC Class Codes: H02J 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields

Abstract

A wireless power feeder 116 feeds power from a feeding coil L2 to a receiving coil L3 by wireless based on a magnetic field resonance phenomenon between the feeding coil L2 and receiving coil L3. A power transmission control circuit 200 supplies AC current at a drive frequency fo to the feeding coil L2. The feeding coil L2 outputs AC power in substantially a non-resonant state with respect to circuit elements on the power feeding side. Then, power is supplied to a receiving coil circuit 130 by a magnetic field resonance between the feeding coil L2 and receiving coil L3.

Claims

1. A wireless power feeder comprising:

a feeding coil; and

a power transmission control circuit that supplies AC current at a drive frequency to the feeding coil so as to make the feeding coil feed AC power to a receiving coil by wireless based on a magnetic field resonance phenomenon between the feeding coil and receiving coil in a state where the feeding coil substantially does not resonate.

2. The wireless power feeder according to claim 1, comprising:

a first switch that controls supply of power supplied from a first direction to the feeding coil; and

a second switch that controls supply of power supplied from a second direction to the feeding coil, wherein

the power transmission control circuit makes the first and second switches alternately conductive to supply AC current to the feeding coil.

3. The wireless power feeder according to claim 2, wherein

current flowing through the first and second switches is supplied, not through a coupling transformer, but directly to the feeding coil.

4. The wireless power feeder according to claim 1, further comprising:

a phase detection circuit that detects the phase difference between voltage and current phases of the AC power.

5. The wireless power feeder according to claim 4, further comprising:

a detection coil that generates inductive current using a magnetic field generated by the AC power, wherein

the phase detection circuit measures the phase of the inductive current to achieve measurement of the current phase of the AC power.

6. The wireless power feeder according to claim 4, wherein

the power transmission control circuit adjusts the drive frequency so as to reduce the detected phase difference.

7. The wireless power feeder according to claim 1, wherein

the feeding coil is provided so as to face the receiving coil, and

a magnetic plate is provided on the feeding coil on the opposite side to the side on which the feeding coil faces the receiving coil.

8. The wireless power feeder according to claim 7, wherein

an electric field shielding plate is further provided on the feeding coil on the opposite side to the side on which the feeding coil faces the receiving coil.

9. The wireless power feeder according to claim 1, wherein

the power transmission control circuit supplies AC current to the feeding coil at a resonance frequency of the receiving coil.

10. A wireless power feeder comprising:

a feeding coil; and

a power transmission control circuit that supplies AC current at a drive frequency to the feeding coil so as to make the feeding coil feed AC power to a receiving coil by wireless based on a magnetic field resonance phenomenon between the feeding coil and receiving coil, wherein

the feeding coil does not form, together with circuit elements on the power feeding side, a resonance circuit having a resonance point corresponding to the resonance frequency of the receiving coil.

11. A wireless power feeder comprising:

a feeding coil; and

a power transmission control circuit that supplies AC current at a drive frequency to the feeding coil so as to make the feeding coil feed AC power to a receiving coil by wireless based on a magnetic field resonance phenomenon between the feeding coil and receiving coil, wherein

no capacitor is connected in series or in parallel to the feeding coil.

12. A wireless power transmission system comprising:

a wireless power feeder; and

a wireless power receiver, wherein

the wireless power feeder comprises;

a feeding coil; and

a power transmission control circuit that supplies AC current at a drive frequency to the feeding coil so as to make the feeding coil feed AC power to a receiving coil in a state where the feeding coil substantially does not resonate, and

the wireless power receiver comprises;

the receiving coil; and

a loading coil that is magnetically coupled to the receiving coil and receives AC power that the receiving coil has received from the feeding coil.

13. The wireless power transmission system according to claim 12, wherein

the wireless power receiver further comprises a capacitor that forms a resonance circuit together with the receiving coil.