POWER TRANSMITTING DEVICE AND POWER RECEIVING DEVICE

• US 20170033609A1
• Filed: 01/29/2015
• Published: 02/02/2017
• Est. Priority Date: 04/25/2014
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: MISAWA, Takahiro, NAKAMURA, Toru, YAMADA, Hideaki
• Granted Patent: US 10,122,216 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B60L 53/124 Detection or removal of foreign bodies
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/60 responsive to the presence of foreign objects, e.g. detection of living beings
• CPC Class Codes: H02J 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 90/12 Electric charging stations
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles

Abstract

A power transmitting device includes a power transmitting coil that forms a magnetic field when an AC voltage is applied thereto and transmits electric power in a non-contact manner to a power receiving coil through the magnetic field, a foreign object detector, a magnetic field detector, and a control device that receives information about a result of detection of a foreign object by the foreign object detector and information about a result of detection of the magnetic field by the magnetic field detector. The control device determines whether there is a foreign object or not based on the result of the detection of a foreign object performed by the foreign object detector during a timing period when the strength of the magnetic field is equal to or lower than a prescribed value.

Claims

1. A power transmitting device that transmits electric power in a non-contact manner to a power receiving device provided outside, comprising:

a power transmitting coil that forms a magnetic field when an AC voltage is applied thereto, and transmits electric power in a non-contact manner to a power receiving coil of said power receiving device through said magnetic field;

a foreign object detector that detects a foreign object located on or in the vicinity of said power transmitting device;

a magnetic field detector that detects said magnetic field; and

a control device that receives information about a result of the detection of a foreign object by said foreign object detector and information about a result of the detection of said magnetic field by said magnetic field detector,

said control device determining whether there is a foreign object or not based on the result of the detection of a foreign object performed by said foreign object detector during a timing period when the strength of said magnetic field is equal to or lower than a prescribed value.

2. The power transmitting device according to claim 1, wherein said magnetic field detector includes a coil where an induced voltage is generated by said magnetic field, and

said timing period when the strength of said magnetic field is equal to or lower than said prescribed value is a timing period when an absolute value of the induced voltage generated in said coil by said magnetic field is equal to or lower than a prescribed value.

3. The power transmitting device according to claim 1, wherein

said foreign object detector includes a first coil that forms a magnetic field for detection when an AC voltage for detection is applied thereto, and a second coil that is arranged to face said first coil and generates an induced voltage by said magnetic field for detection formed by said first coil, and

said control device determines whether there is a foreign object or not based on a power receiving state of said second coil, said power receiving state being calculated from a value of the induced voltage generated in said second coil by said magnetic field for detection.

4. The power transmitting device according to claim 3, wherein

said first coil and said second coil form a pair of coils,

said foreign object detector includes a plurality of said pairs of coils,

said power transmitting device further comprises a switching device that switches between pairs of coils to be selected of said plurality of pairs of coils, and

said switching device successively switches between combinations of said first coil to which the AC voltage for detection is applied and said second coil whose induced voltage is calculated by successively switching between pairs of coils to be selected of said plurality of pairs of coils at each said timing period.

5. The power transmitting device according to claim 4, wherein

said switching device includes

a first multiplexer connected to one terminal of each of the plurality of first coils via a first common line,

a second multiplexer connected to the other terminal of each of the plurality of first coils via a second common line,

a third multiplexer connected to one terminal of each of the plurality of second coils via a third common line, and

a fourth multiplexer connected to the other terminal of each of the plurality of second coils via a fourth common line.

6. The power transmitting device according to claim 3, wherein

each of said first coil and said second coil has a shape formed by arranging a pair of coil elements having the same number of turns and wound in opposite directions on the same plane and connecting said pair of coil elements in series with each other.

9. The power transmitting device according to claim 2, wherein

said foreign object detector includes a first coil that forms a magnetic field for detection when an AC voltage for detection is applied thereto, and a second coil that is arranged to face said first coil and generates an induced voltage by said magnetic field for detection formed by said first coil, and

said control device determines whether there is a foreign object or not based on a power receiving state of said second coil, said power receiving state being calculated from a value of the induced voltage generated in said second coil by said magnetic field for detection.

10. The power transmitting device according to claim 9, wherein

said first coil and said second coil form a pair of coils,

said foreign object detector includes a plurality of said pairs of coils,

said power transmitting device further comprises a switching device that switches between pairs of coils to be selected of said plurality of pairs of coils, and

said switching device successively switches between combinations of said first coil to which the AC voltage for detection is applied and said second coil whose induced voltage is calculated by successively switching between pairs of coils to be selected of said plurality of pairs of coils at each said timing period.

11. The power transmitting device according to claim 9, wherein

said switching device includes

a first multiplexer connected to one terminal of each of the plurality of first coils via a first common line,

a second multiplexer connected to the other terminal of each of the plurality of first coils via a second common line,

a third multiplexer connected to one terminal of each of the plurality of second coils via a third common line, and

a fourth multiplexer connected to the other terminal of each of the plurality of second coils via a fourth common line.

12. The power transmitting device according to claim 9, wherein

each of said first coil and said second coil has a shape formed by arranging a pair of coil elements having the same number of turns and wound in opposite directions on the same plane and connecting said pair of coil elements in series with each other.

13. The power transmitting device according to claim 4, wherein

each of said first coil and said second coil has a shape formed by arranging a pair of coil elements having the same number of turns and wound in opposite directions on the same plane and connecting said pair of coil elements in series with each other.

14. The power transmitting device according to claim 10, wherein

each of said first coil and said second coil has a shape formed by arranging a pair of coil elements having the same number of turns and wound in opposite directions on the same plane and connecting said pair of coil elements in series with each other.

15. The power transmitting device according to claim 5, wherein

each of said first coil and said second coil has a shape formed by arranging a pair of coil elements having the same number of turns and wound in opposite directions on the same plane and connecting said pair of coil elements in series with each other.

16. The power transmitting device according to claim 11, wherein

each of said first coil and said second coil has a shape formed by arranging a pair of coil elements having the same number of turns and wound in opposite directions on the same plane and connecting said pair of coil elements in series with each other.

7. A power receiving device that receives electric power in a non-contact manner from a power transmitting device provided outside, comprising:

a power receiving coil that receives electric power in a non-contact manner from a power transmitting coil of said power transmitting device through a magnetic field, said magnetic field being formed by said power transmitting coil when an AC voltage is applied thereto;

a foreign object detector that detects a foreign object located below or in the vicinity of said power receiving device;

a magnetic field detector that detects said magnetic field; and

a control device that receives information about a result of the detection of a foreign object by said foreign object detector and information about a result of the detection of said magnetic field by said magnetic field detector,

said control device determining whether there is a foreign object or not based on the result of the detection of a foreign object performed by said foreign object detector during a timing period when the strength of said magnetic field is equal to or lower than a prescribed value.

8. The power receiving device according to claim 7, wherein

said magnetic field detector includes a coil where an induced voltage is generated by said magnetic field, and

said timing period when the strength of said magnetic field is equal to or lower than said prescribed value is a timing period when an absolute value of the induced voltage generated in said coil by said magnetic field is equal to or lower than a prescribed value.