Wireless power feeder and wireless power feeding method

• US 9,438,068 B2
• Filed: 04/01/2014
• Issued: 09/06/2016
• Est. Priority Date: 04/03/2013
• Status: Active Grant

• Current Assignee: Maxell, Ltd.
• Original Assignee: Funai Electric Co., Ltd.
• Inventors: Wakabayashi, Naoyuki
• Primary Examiner(s): Memula, Suresh
• Application Number:
  US14/242,176
• Publication Number:
  US 20140300315A1
• Time in Patent Office: 889 Days
• Field of Search: 320/108
• US Class Current: 1/1
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/402 the two or more transmitting or the two or more receiving devices being integrated in the same unit, e.g. power mats with several coils or antennas with several sub-antennas
• CPC Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H02J 7/00302 Overcharge protection
• CPC Class Codes: H02J 7/0049 Detection of fully charged condition
• CPC Class Codes: H02J 7/007 Regulation of charging or discharging current or voltage
• CPC Class Codes: H02J 7/02 for charging batteries from ac mains by converters
• CPC Class Codes: Y02B 40/00 Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers

Abstract

A non-contact power feeder includes a plurality of power transmission coils disposed along a disposition surface, wherein a power receiving device that houses a power reception coil is disposed on the disposition surface, and a controller that determines a first traveling wave power, from among a plurality of traveling wave powers, that feeds the power transmission coil corresponding to the power receiving device based on a state of change of at least one of: actual transmitted power, from the plurality of traveling wave powers, transmitted from the plurality of power transmission coils to the power reception coil when power transmitted to the plurality of power transmission coils is changed, and reactive power, from the plurality of traveling wave powers, not transmitted from the power transmission coil to the power reception coil when the power transmitted to the plurality of power transmission coils is changed.

Claims

1. A wireless power feeder, comprising:

a power transmission coil that feeds power to a power reception coil provided with a power receiving device; and

a controller that determines power transmitted to the power transmission coil based on a change of a slope of at least one of actual transmitted power and reactive power, wherein

the actual transmitted power is transmitted from the power transmission coil to the power reception coil, and

the reactive power is not transmitted from the power transmission coil to the power reception coil.

2. The wireless power feeder according to claim 1, wherein the controller determines the power transmitted to the power transmission coil based further on a change of the slope of both of the actual transmitted power and the reactive power.

3. The wireless power feeder according to claim 2, wherein the controller obtains an inflection point where the slope of the actual transmitted power changes, and determines the power transmitted to the power transmission coil as power corresponding to the inflection point.

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

at least one more power transmission coil, wherein

the controller, by driving the power transmission coils and measuring the actual transmitted power, detects one or more of the power transmission coils for which the actual transmitted power is greater than the actual transmitted power for the other power transmission coils.

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

the controller determines a combination of two or more power transmission coils as the power transmission coils that feed the actual transmitted power to the power receiving device.

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

at least one more power receiving device is disposed on a disposition surface, and

the controller determines a second traveling wave power that feeds the power transmission coil corresponding to each of the power receiving devices based on a ratio of a first traveling wave power corresponding to the each power receiving device instead of the first traveling wave power when a sum of the first traveling wave power corresponding to the each power receiving device exceeds a power feeding capacity of the wireless power feeder.

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

a plurality of pressure sensors disposed at intervals along a disposition surface that detects a position where the power receiving device is disposed on the disposition surface, wherein

the actual transmitted power of only the power transmission coil near a position where the plurality of pressure sensors detects disposition of the power receiving device is measured.

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

a directional coupler, wherein

the controller calculates the actual transmitted power by reducing a reflected wave power from the traveling wave power measured by the directional coupler.

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

at least one more power receiving device is disposed on a disposition surface, wherein the wireless power feeder further comprises:

a display that displays a charging state and a size of the actual transmitted power corresponding to each of power receiving devices during charging.

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

a plurality of lamps provided on the power transmission coil, wherein

one or more of the lamps near the power transmission coil light up during charging.

11. The wireless power feeder according to claim 1, wherein the controller continuously or at predetermined times measures the actual transmitted power fed to the power reception coil during power feeding and stops charging the power receiving device by stopping power feeding when a drop in the actual transmitted power is detected.

12. A wireless power feeding method for a wireless power feeder comprising a plurality of power transmission coils disposed along a disposition surface and a controller, a power receiving device that houses a power reception coil being disposed on the disposition surface, the method comprising:

changing, with the controller, a traveling wave power that is transmitted to the power transmission coils corresponding to the power receiving device; and

determining, with the controller, a first traveling wave power, from the changed traveling wave power, based on a state of change of a change amount of at least one of actual transmitted power and reactive power relative to a changed amount of the changed traveling wave power,

feeding, with the controller, the determined first traveling wave power to a power transmission coil corresponding to the power receiving device, wherein

the actual transmitted power is transmitted from the plurality of power transmission coils to the power reception coil, and

the reactive power is not transmitted from the power transmission coil to the power reception coil.

13. The wireless power feeding method according to claim 12, further comprising:

obtaining, with the controller, an inflection point between at least one of the actual transmitted power and the reactive power and the traveling wave power; and

determining, with the controller, the traveling wave power at a time when the inflection point is obtained as the first traveling wave power.

14. The wireless power feeding method according to claim 12, further comprising:

driving, with the controller, the plurality of power transmission coils and measuring the actual transmitted power; and

detecting, with the controller, one or more of the power transmission coils for which the actual transmitted power is maximum as the power transmission coil that feeds the actual transmitted power to the disposed power receiving device.

15. The wireless power feeding method according to claim 14, further comprising:

sequentially adding and driving, with the controller, the power transmission coils around the detected power transmission coil for which the actual transmitted power is the maximum value;

detecting, with the controller, the power transmission coil for which the actual transmitted power increases; and

determining, with the controller, a power transmission coil cluster as the power transmission coil that feeds the actual transmitted power to the disposed power receiving device, wherein the power transmission coil cluster is a combination of one or more sets of power transmission coils used in power feeding.

16. The wireless power feeding method according to claim 12, wherein a plurality of power receiving devices is disposed on the disposition surface and the method further comprises:

determining, with the controller, a second traveling wave power that feeds the power transmission coil corresponding to each of the power receiving devices based on a ratio of the first traveling wave power corresponding to the each power receiving device instead of the first traveling wave power when a sum of the first traveling wave power corresponding to the each power receiving device exceeds a power feeding capacity of the wireless power feeder.

17. The wireless power feeding method according to claim 12, further comprising:

calculating, with the controller, the actual transmitted power by reducing a reflected wave power from the traveling wave power measured by a directional coupler.

18. The wireless power feeding method according to claim 12, further comprising continuously or at predetermined times measuring, with the controller, the actual transmitted power fed to the power reception coil during power feeding and stopping charging the power receiving device by stopping power feeding when a drop in the actual transmitted power is detected.