US-12620838-B2 - Contactless power feeding apparatus and contactless power feeding system

US12620838B2US 12620838 B2US12620838 B2US 12620838B2US-12620838-B2

Abstract

A contactless power feeding apparatus includes a plurality of primary coils mounted on a road and a power feed controller which uses a portion of the primary coils as a power transmitting coil to achieve delivery of electrical power from the power transmitting coil to a secondary coil mounted in a vehicle. The power feed controller uses a selected primary coil that is one of the primary coils other than the power transmitting coil to decrease a leakage of magnetic flux arising from excitation of the power transmitting coil. Instead of the selected primary coil, the secondary coil may be used to reduce the leakage of magnetic flux.

Inventors

Hayato SUMIYA
Kazuhiro Uda
Eisuke Takahashi
Nobuhisa Yamaguchi
Kazuyoshi Obayashi
Shimpei Takita
Koji MAZAKI
Mitsuru Shibanuma
Masaki Kanesaki
Takuya KIGUCHI

Assignees

DENSO CORPORATION

Dates

Publication Date: 20260505
Application Date: 20250107
Priority Date: 20180718

Claims (8)

1 . A contactless power feeding apparatus which feeds electrical power to a traveling vehicle in a contactless mode comprising: a plurality of primary coils which are mounted on a road, each of the plurality of primary coils being configured to both: (i) deliver electrical power to a secondary coil installed in the traveling vehicle, and (ii) reduce a leakage of magnetic flux resulting from excitation of a primary coil selected as a power transmitting coil; a power feed controller configured to: select one of the primary coils as the power transmitting coil to achieve delivery of electrical power from the power transmitting coil to the secondary coil installed in the vehicle; and a coil position detector configured to measure a gap between the primary coils and the secondary coil, wherein the power feed controller is further configured to use a value of the gap to select one of the primary coils, which is not used in delivering the electrical power to the secondary coil in the vehicle, as a selected primary coil and use the selected primary coil to reduce a leakage of magnetic flux resulting from excitation of the power transmitting coil.
2 . The contactless power feeding apparatus as set forth in claim 1 , wherein the power feed controller works to control a circuit device which is connected to the selected primary coil to create a flow of electrical current through the selected primary coil in a direction to reduce the leakage of magnetic flux.
3 . The contactless power feeding apparatus as set forth in claim 2 , wherein the power feed controller produces an electrical current which flows through the selected primary coil in a phase suitable for reducing the leakage of magnetic flux.
4 . The contactless power feeding apparatus as set forth in claim 3 , wherein the power feed controller selects the electrical current flowing through the selected primary coil which is lower than that flowing through the power transmitting coil.
5 . The contactless power feeding apparatus as set forth in claim 4 , further comprising a magnetic flux leakage detector which detects the leakage of magnetic flux, and wherein the power feed controller works to control the electrical current flowing through the selected primary coil as a function of the leakage of magnetic flux detected by the magnetic flux leakage detector.
6 . The contactless power feeding apparatus as set forth in claim 2 , wherein the power feed controller uses, as the selected primary coil, one of the primary coils which delivers electrical power to a second vehicle other than said vehicle.
7 . The contactless power feeding apparatus as set forth in claim 1 , wherein the power feed controller short-circuits ends of the selected primary coil to reduce the leakage of magnetic flux.
8 . A contactless power feeding system which uses a plurality of primary coils mounted on a road and a secondary coil installed in a vehicle, the system comprising: a power feed controller configured to: select one of the primary coils as a power transmitting coil to achieve feeding of electrical power from the power transmitting coil to the secondary coil, each of the plurality of primary coils being configured to both: (i) deliver the electrical power to the vehicle in a contactless mode during traveling of the vehicle, and (ii) reduce a leakage of magnetic flux resulting from excitation of a primary coil selected as the power transmitting coil; a coil position detector configured to measure a gap between the primary coils and the secondary coil; and a control device which controls operation of the secondary coil, wherein at least one of a first operation and a second operation is executed, the power feed controller is configured to execute the first operation to use a value of the gap to select one of the primary coils, which is not used in delivering the electrical power to the vehicle, to reduce the leakage of magnetic flux resulting from excitation of the power transmitting coil, and the control device is configured to execute the second operation to create a flow of electrical current through the secondary coil when the secondary coil is not receiving the electrical power to reduce the leakage of magnetic flux arising from the excitation of the power transmitting coil.

Description

CROSS REFERENCE TO RELATED DOCUMENTS The present application is a divisional of U.S. application Ser. No. 17/150,351, filed Jan. 15, 2021, which claims the benefit of priority of Japanese Patent Application No. 2018-135060 filed on Jul. 18, 2018 and Japanese Patent Application No. 2019-038160 filed on Mar. 4, 2019, the disclosures of which are incorporated herein by reference. TECHNICAL FIELD This disclosure generally relates to a technique for feeding electrical power to a vehicle in a contactless mode during traveling of the vehicle. BACKGROUND ART Japanese Patent First Publication No. 2014-110726A discloses a technique for feeding electrical power to a vehicle in a contactless mode. This prior art technique reduces a leakage of magnetic flux using canceller coils. The canceller coils are disposed behind a power feeding coil and a power receiving coil. SUMMARY OF THE INVENTION The above prior art technique is required to have the canceller coils in addition to the power feeding coil, thus resulting in undesirable increases in size and production cost of the apparatus. The above prior art technique relates to power feeding when a vehicle is stopped and thus faces a problem that it cannot be used for feeding the power to the vehicle when traveling. A technique for reducing leakage of power when the power is supplied to a traveling vehicle in the contactless mode is, therefore, sought. According to one aspect of this disclosure, there is provided a contactless power feeding apparatus which feeds electrical power to a traveling vehicle in a contactless mode. The contactless power feeding apparatus comprises a plurality of primary coils which are mounted on a road, and a power feed controller which uses one(s) of the primary coils as a power transmitting coil to achieve delivery of electrical power from the power transmitting coil to a secondary coil installed in the vehicle. The power feed controller works to use a selected primary coil(s) that is one(s) of the primary coils other than the power transmitting coil to reduce a leakage of magnetic flux resulting from excitation of the power transmitting coil. The contactless power feeding apparatus is capable of reduce the leakage of magnetic flux without any need for an additional canceller coil in addition to the primary coils. According to another aspect of this disclosure, there is provided a contactless power feeding system which uses a plurality of primary coils mounted on a road and a secondary coil installed in a vehicle to feed electrical power to the vehicle in a contactless mode during traveling of the vehicle. The contactless power feeding system comprises a power feed controller which uses one(s) of the primary coils as a power transmitting coil to achieve feeding of the electrical power from the power transmitting coil, and a control device which controls an operation of the secondary coil. The contactless power feeding system executes at least one of a first operation and a second operation. The first operation is performed by the power feed controller to use one(s) of the primary coils other than the power transmitting coil to reduce a leakage of magnetic flux arising from excitation of the power transmitting coil. The second operation is performed by the control device to create a flow of electrical current through the secondary coil when the secondary coil is not receiving the electrical power to reduce the leakage of magnetic flux arising from the excitation of the power transmitting coil. The contactless power feeding apparatus is capable of reducing the leakage of magnetic flux without need for a canceller coil in addition the primary coils. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram which illustrates an entire structure of a during-traveling contactless power feeding system. FIG. 2 is an explanatory view which illustrates a power feeding section arranged on a traffic lane. FIG. 3 is an explanatory view which illustrates examples of coil structures of a primary coil and a secondary coil. FIG. 4 is an explanatory view which shows power transmitting coils and canceller coils in the first embodiment. FIG. 5 is an explanatory view which illustrates a decrease in leakage of magnetic flux by a canceller coil. FIG. 6A is an explanatory view which illustrates an example of a circuit structure of a power feeding circuit and a power feeding coil. FIG. 6B is an explanatory view which shows an example of a circuit structure of a power feeding circuit and a power feeding coil. FIG. 7 is a graph which represents an example of a relation between a gap G between a primary coil and a secondary coil and a distance L between a power transmitting coil and a canceller coil. FIG. 8 is an explanatory view which illustrates power transmitting coils and canceller coils in the second embodiment. FIG. 9 is an explanatory view which illustrates examples of circuit structures of a power feeding circuit and a power feeding coil in the second embodiment.