POWER TRANSMISSION DEVICE, POWER RECEPTION DEVICE AND NON-CONTACT POWER FEEDING SYSTEM

• US 20180205255A1
• Filed: 07/05/2016
• Published: 07/19/2018
• Est. Priority Date: 07/08/2015
• Status: Active Grant

• Current Assignee: ROHM Co., Ltd.
• Original Assignee: ROHM Co., Ltd.
• Inventors: IKEFUJI, Yoshihiro, OKUI, Akihiro, UTSUNOMIYA, Kimitake
• Granted Patent: US 10,923,962 B2
• Time in Patent Office: Days
• CPC Class Codes: H01F 27/40 Structural association with built-in electric component, e.g. fuse
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: H02J 50/005 Mechanical details of housing or structure aiming to accommodate the power transfer means, e.g. mechanical integration of coils, antennas or transducers into emitting or receiving devices
• 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: H04B 5/26 using coils
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer
• CPC Class Codes: H04M 1/04 Supports for telephone transmitters or receivers

Abstract

In a non-contact power feeding system which is formed with a power transmission device having a power transmission-side resonant circuit including a power transmission-side coil and a power reception device having a power reception-side resonant circuit including a power reception-side coil and which can transmit and receive power by a magnetic field resonance method, when the power is transmitted, the power transmission device monitors the amplitude of a current flowing through the power transmission-side coil. Then, when a current amplitude detection value (V_mFOD) falls outside a predetermined normal range, it is determined that a foreign object is present, and thus the power transmission is stopped.

Claims

1. A power transmission device which can transmit power to a power reception device by a magnetic field resonance method, the power transmission device comprising:

a power transmission-side resonant circuit which includes a power transmission-side coil that transmits the power;

a power transmission circuit which can supply an alternating current voltage to the power transmission-side resonant circuit;

a detection circuit which detects an amplitude of a current flowing through the power transmission-side coil; and

a control circuit which performs power transmission control on the power by controlling the power transmission circuit,

wherein when the power is transmitted, the control circuit controls, based on an amplitude detection value of the detection circuit, whether or not continuation of the power transmission is allowed.

2. The power transmission device according to claim 1,

wherein when the power is transmitted, the control circuit monitors whether or not the amplitude detection value of the detection circuit falls outside a predetermined range so as to control whether or not the continuation of the power transmission is allowed.

3. The power transmission device according to claim 2,

wherein while the power is transmitted, when the control circuit detects that the amplitude detection value of the detection circuit falls outside the predetermined range, the control circuit stops the power transmission.

4. The power transmission device according to claim 2 or 3,

wherein when the power is transmitted, the control circuit determines whether or not the amplitude detection value of the detection circuit falls outside the predetermined range so as to determine whether or not a foreign object is present which is different from the power reception device and which can generate a current based on a magnetic field generated in the power transmission-side coil, and when the control circuit determines that the foreign object is present, the control circuit stops the power transmission.

5. The power transmission device according to claim 4,

wherein when the power is transmitted, the control circuit determines whether or not the amplitude detection value of the detection circuit exceeds an upper limit value of the predetermined range so as to determine whether or not as the foreign object, a foreign object including a coil is present.

6. The power transmission device according to any one of claims 1 to 5,

wherein the power reception device includes:

a power reception-side resonant circuit which includes a power reception-side coil that receives the power; and

a change/short circuit which changes a resonant frequency of the power reception-side resonant circuit from a resonant frequency when the power is received or short-circuits the power reception-side coil before the reception of the power,

the control circuit includes;

a first processing portion which controls the power transmission circuit such that in a state where the power reception device changes the resonant frequency of the power reception-side resonant circuit or short-circuits the power reception-side coil according to a signal provided by communication from the power transmission device, a predetermined test magnetic field is generated in the power transmission-side coil before the transmission of the power;

a second processing portion which determines, based on the amplitude detection value of the detection circuit when the test magnetic field is generated, whether or not the power transmission can be performed; and

a third processing portion which realizes the power transmission by controlling the power transmission circuit such that after it is determined that the power transmission can be performed, a power transmission magnetic field larger than the test magnetic field is generated in the power transmission-side coil and

the detection circuit detects, through processing which amplifies a signal indicating the amplitude of the current flowing through the power transmission-side coil, the amplitude, and an amplification factor in the amplification when the power transmission magnetic field is generated in the power transmission-side coil is smaller than an amplification factor in the amplification when the test magnetic field is generated in the power transmission-side coil.

7. A non-contact power feeding system which comprises:

a power transmission device having a power transmission-side resonant circuit including a power transmission-side coil that transmits power; and

a power reception device having a power reception-side resonant circuit including a power reception-side coil that receives the power and which can transmit and receive the power by a magnetic field resonance method,

wherein the power transmission device includes;

a power transmission circuit which can supply an alternating current voltage to the power transmission-side resonant circuit;

a detection circuit which detects an amplitude of a current flowing through the power transmission-side coil; and

a control circuit which performs power transmission control on the power by controlling the power transmission circuit, and

when the power is transmitted, the control circuit controls, based on an amplitude detection value of the detection circuit, whether or not continuation of the power transmission is allowed.

8. The non-contact power feeding system according to claim 7,

wherein when the power is transmitted, the control circuit monitors whether or not the amplitude detection value of the detection circuit falls outside a predetermined range so as to control whether or not the continuation of the power transmission is allowed.

9. The non-contact power feeding system according to claim 8,

wherein while the power is transmitted, when the control circuit detects that the amplitude detection value of the detection circuit falls outside the predetermined range, the control circuit stops the power transmission.

10. The non-contact power feeding system according to claim 8 or 9,

wherein when the power is transmitted, the control circuit determines whether or not the amplitude detection value of the detection circuit falls outside the predetermined range so as to determine whether or not a foreign object is present which is different from the power reception device and which can generate a current based on a magnetic field generated in the power transmission-side coil, and when the control circuit determines that the foreign object is present, the control circuit stops the power transmission.

11. The non-contact power feeding system according to claim 10,

wherein when the power is transmitted, the control circuit determines whether or not the amplitude detection value of the detection circuit exceeds an upper limit value of the predetermined range so as to determine whether or not as the foreign object, a foreign object including a coil is present.

12. The non-contact power feeding system according to any one of claims 7 to 11,

wherein the power reception device includes a change/short circuit which changes a resonant frequency of the power reception-side resonant circuit from a resonant frequency when the power is received or short-circuits the power reception-side coil before the reception of the power,

the control circuit includes:

a first processing portion which controls the power transmission circuit such that in a state where the power reception device changes the resonant frequency of the power reception-side resonant circuit or short-circuits the power reception-side coil according to a signal provided by communication from the power transmission device, a predetermined test magnetic field is generated in the power transmission-side coil before the transmission of the power;

a second processing portion which determines, based on the amplitude detection value of the detection circuit when the test magnetic field is generated, whether or not the power transmission can be performed; and

a third processing portion which realizes the power transmission by controlling the power transmission circuit such that after it is determined that the power transmission can be performed, a power transmission magnetic field larger than the test magnetic field is generated in the power transmission-side coil and

the detection circuit detects, through processing which amplifies a signal indicating the amplitude of the current flowing through the power transmission-side coil, the amplitude, and an amplification factor in the amplification when the power transmission magnetic field is generated in the power transmission-side coil is smaller than an amplification factor in the amplification when the test magnetic field is generated in the power transmission-side coil.

13. A power reception device which can receive, from a power transmission device having a power transmission-side resonant circuit including a power transmission-side coil that transmits power, the power by a magnetic field resonance method, the power reception device comprising:

a power reception-side resonant circuit that includes a power reception-side coil that receives the power; and

a metal portion that includes a metal plate in which an opening portion is provided in a position opposite an arrangement position of the power reception-side coil,

wherein when the power transmission device and the power reception device are in a predetermined positional relationship for performing the transmission and reception of the power, the opening portion is located between the power transmission-side coil and the power reception-side coil, and a magnetic member portion is provided in such a position as to affect at least one of a resonant frequency of the power reception-side resonant circuit and a resonant frequency of the power transmission-side resonant circuit.

14. The power reception device according to claim 13,

wherein the magnetic member portion includes a magnetic member within the opening portion which is arranged in the opening portion.

15. The power reception device according to claim 14,

wherein the magnetic member within the opening portion cancels a change in the resonant frequency of the power reception-side resonant circuit caused by the metal plate and cancels a change in the resonant frequency of the power transmission-side resonant circuit caused by the metal plate in the predetermined positional relationship.

16. The power reception device according to claim 14 or 15,

wherein in the predetermined positional relationship, a distance between the power reception-side coil and the magnetic member within the opening portion is equal to a distance between the power transmission-side coil and the magnetic member within the opening portion.

17. The power reception device according to any one of claims 14 to 16,

wherein the opening portion is sealed by the magnetic member within the opening portion.

18. The power reception device according to any one of claims 14 to 17,

wherein the magnetic member within the opening portion is a magnetic member plate which is fitted into the opening portion, and

one surface of the magnetic member plate and one surface of the metal plate are located on a same plane, and the other surface of the magnetic member plate and the other surface of the metal plate are located on a same plane parallel to the plane.

19. The power reception device according to claim 13,

wherein the power reception-side coil is arranged between the magnetic member portion and the metal plate,

the transmission and reception of the power are performed in a state where the resonant frequencies of the power transmission-side resonant circuit and the power reception-side resonant circuit are set to a predetermined reference frequency,

the magnetic member portion cancels a change in the resonant frequency of the power reception-side resonant circuit from the reference frequency caused by the metal plate and

in the predetermined positional relationship, the resonant frequency of the power transmission-side resonant circuit is changed to the reference frequency through a change in the resonant frequency of the power transmission-side resonant circuit which is affected by the metal plate.

20. The power reception device according to claim 19,

wherein an electronic circuit is provided which includes an integrated circuit on a side opposite to the magnetic member portion when seen from the power reception-side coil.

21. The power reception device according to claim 13,

wherein the metal plate is arranged between the power reception-side coil and the magnetic member portion,

the transmission and reception of the power are performed in a state where the resonant frequencies of the power transmission-side resonant circuit and the power reception-side resonant circuit are set to a predetermined reference frequency,

the magnetic member portion cancels a change in the resonant frequency of the power transmission-side resonant circuit from the reference frequency caused by the metal plate in the predetermined positional relationship and

the resonant frequency of the power reception-side resonant circuit is changed to the reference frequency through a change in the resonant frequency of the power reception-side resonant circuit which is affected by the metal plate.

22. The power reception device according to claim 13,

wherein the magnetic member portion is arranged between the power reception-side coil and the metal plate,

the transmission and reception of the power are performed in a state where the resonant frequencies of the power transmission-side resonant circuit and the power reception-side resonant circuit are set to a predetermined reference frequency,

the magnetic member portion cancels a change in the resonant frequency of the power reception-side resonant circuit from the reference frequency caused by the metal plate and

in the predetermined positional relationship, the resonant frequency of the power transmission-side resonant circuit is changed to the reference frequency through a change in the resonant frequency of the power transmission-side resonant circuit which is affected by the metal plate.

23. The power reception device according to any one of claims 13 to 22,

wherein the magnetic member portion is formed of ferrite.

24. The power reception device according to any one of claims 13 to 23,

wherein the metal plate is formed of aluminum or an aluminum alloy.

25. The power reception device according to any one of claims 13 to 24,

wherein an enclosure of the power reception device is formed with the metal portion.

26. A non-contact power feeding system comprising:

the power reception device according to any one of claims 13 to 25; and

the power transmission device which has the power transmission-side resonant circuit including the power transmission-side coil that transmits the power,

wherein the transmission and reception of the power can be performed by the magnetic field resonance method.

27. The non-contact power feeding system according to claim 26,

wherein the power transmission device includes:

a power transmission circuit which can supply an alternating current voltage to the power transmission-side resonant circuit;

a detection circuit which detects an amplitude of a current flowing through the power transmission-side coil; and

a control circuit which performs power transmission control on the power by controlling the power transmission circuit based on an amplitude detection value of the detection circuit.

28. The non-contact power feeding system according to claim 27,

wherein the power reception device includes a change/short circuit which changes the resonant frequency of the power reception-side resonant circuit from a resonant frequency when the power is received or short-circuits the power reception-side coil before the reception of the power from the power transmission device,

the control circuit includes:

a first processing portion which controls the power transmission circuit such that in a state where the power reception device changes the resonant frequency of the power reception-side resonant circuit or short-circuits the power reception-side coil according to a signal provided by communication from the power transmission device, a predetermined test magnetic field is generated in the power transmission-side coil before the transmission of the power;

a second processing portion which determines, based on the amplitude detection value of the detection circuit when the test magnetic field is generated, whether or not the power transmission can be performed; and

a third processing portion which realizes the power transmission by controlling the power transmission circuit such that after it is determined that the power transmission can be performed, a power transmission magnetic field larger than the test magnetic field is generated in the power transmission-side coil and

based on the magnetic field generated in the power transmission-side coil, currents in directions opposite to each other flow through the metal plate and the magnetic member portion.

29. A power reception device which can receive, from a power transmission device having a power transmission-side resonant circuit including a power transmission-side coil that transmits power, the power by a magnetic field resonance method, the power reception device comprising:

a power reception-side resonant circuit which includes a power reception-side coil that receives the power; and

a metal portion that includes a metal plate in which an opening portion is provided in a position opposite an arrangement position of the power reception-side coil,

wherein when the power transmission device and the power reception device are in a predetermined positional relationship for performing the transmission and reception of the power, the opening portion is located between the power transmission-side coil and the power reception-side coil, and

in the metal plate, a slit portion is formed from the opening portion toward an outer periphery of the metal plate.

30. The power reception device according to claim 29,

wherein the slit portion includes a cut slit which is extended from the opening portion to the outer periphery of the metal plate.

31. The power reception device according to claim 30,

wherein the metal portion includes, as the metal plate,

a first metal plate in which a first opening portion is provided in the position opposite the arrangement position of the power reception-side coil and

a second metal plate in which a second opening portion is provided in the position opposite the arrangement position of the power reception-side coil,

the first metal plate and the second metal plate are coupled to each other through an insulating member, and in the predetermined positional relationship, the first opening portion and the second opening portion are located between the power transmission-side coil and the power reception-side coil,

the slit portion includes, as the cut slit,

a first cut slit which is extended from the first opening portion to an outer periphery of the first metal plate and

a second cut slit which is extended from the second opening portion to an outer periphery of the second metal plate and

within a plane parallel to the first metal plate and the second metal plate, the first cut slit and the second cut slit are formed in different positions.

32. The power reception device according to claim 29,

wherein the slit portion includes a plurality of slits which are formed in different positions from the opening portion toward the outer periphery of the metal plate, and

a metal of the metal plate is left between each of the slits and the outer periphery of the metal plate.

33. The power reception device according to claim 32,

wherein the slits are formed radially from the opening portion toward the outer periphery of the metal plate.

34. The power reception device according to claim 32 or 33,

wherein the transmission and reception of the power are performed in a state where resonant frequencies of the power transmission-side resonant circuit and the power reception-side resonant circuit are set to a predetermined reference frequency, and

in the predetermined positional relationship, the resonant frequencies of the power transmission-side resonant circuit and the power reception-side resonant circuit are changed to the reference frequency through changes in the resonant frequencies of the power transmission-side resonant circuit and the power reception-side resonant circuit which are affected by the metal plate.

35. The power reception device according to any one of claims 29 to 34,

wherein the metal plate is formed of aluminum or an aluminum alloy.

36. The power reception device according to any one of claims 29 to 35,

wherein an enclosure of the power reception device is formed with the metal portion.

37. A non-contact power feeding system comprising:

the power reception device according to any one of claims 29 to 36; and

the power transmission device which has the power transmission-side resonant circuit including the power transmission-side coil that transmits the power,

wherein the transmission and reception of the power can be performed by the magnetic field resonance method.

38. The non-contact power feeding system according to claim 37,

wherein the power transmission device includes:

a power transmission circuit which can supply an alternating current voltage to the power transmission-side resonant circuit;

a detection circuit which detects an amplitude of a current flowing through the power transmission-side coil; and

a control circuit which performs power transmission control on the power by controlling the power transmission circuit based on an amplitude detection value of the detection circuit.

39. The non-contact power feeding system according to claim 38,

wherein the power reception device includes a change/short circuit which changes the resonant frequency of the power reception-side resonant circuit from a resonant frequency when the power is received or short-circuits the power reception-side coil before the reception of the power from the power transmission device, and

the control circuit includes:

a first processing portion which controls the power transmission circuit such that in a state where the power reception device changes the resonant frequency of the power reception-side resonant circuit or short-circuits the power reception-side coil according to a signal provided by communication from the power transmission device, a predetermined test magnetic field is generated in the power transmission-side coil before the transmission of the power;

a second processing portion which determines, based on the amplitude detection value of the detection circuit when the test magnetic field is generated, whether or not the power transmission can be performed; and

a third processing portion which realizes the power transmission by controlling the power transmission circuit such that after it is determined that the power transmission can be performed, a power transmission magnetic field larger than the test magnetic field is generated in the power transmission-side coil.