CONTACTLESS POWER TRANSFER SYSTEM FOR MOVABLE OBJECT

• US 20140239735A1
• Filed: 09/07/2012
• Published: 08/28/2014
• Est. Priority Date: 09/09/2011
• Status: Abandoned Application

• Current Assignee: Technova, Inc. (Aisin Corp.)
• Original Assignee: Technova, Inc. (Aisin Corp.)
• Inventors: Abe, Shigeru, Yasuda, Tomio, Suzuki, Akira, Hosoi, Nobuhiro
• Application Number:
  US14/343,503
• Publication Number:
  US 20140239735A1
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: B60L 2210/30 AC to DC converters
• CPC Class Codes: B60L 2210/40 DC to AC converters
• CPC Class Codes: B60L 2240/36 Temperature of vehicle components or parts
• CPC Class Codes: B60L 2250/10 by alarm
• CPC Class Codes: B60L 2270/147 electro magnetic [EMI]
• CPC Class Codes: B60L 3/0069 relating to the isolation, e.g. ground fault or leak current
• CPC Class Codes: B60L 3/04 Cutting off the power supply under fault conditions protective devices and circuit arrangements in general H01H; H02H
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 53/122 Circuits or methods for driving the primary coil, e.g. supplying electric power to the coil
• CPC Class Codes: B60L 53/124 Detection or removal of foreign bodies
• CPC Class Codes: B60L 53/126 Methods for pairing a vehicle and a charging station, e.g. establishing a one-to-one relation between a wireless power transmitter and a wireless power receiver
• CPC Class Codes: B60L 53/36 by positioning the vehicle
• CPC Class Codes: H02J 2310/48 for electric vehicles [EV] or hybrid vehicles [HEV]
• CPC Class Codes: H02J 50/10 using inductive coupling
• 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 50/80 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: H02M 1/0085 Partially controlled bridges
• 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 10/72 : Electric energy management in electromobility
• CPC Class Codes: Y02T 90/12 : Electric charging stations
• CPC Class Codes: Y02T 90/14 : Plug-in electric vehicles

Abstract

In an example of a system, power is transferred from a transmission coil to a reception coil by electromagnetic induction. A detecting unit calculates a difference between a standard value and a measured value, detects presence of a metallic foreign object on the transmission coil based on the difference, and outputs a signal when the metallic foreign object is detected. The standard value is obtained by supplying electrical power to the transmission coil when a metallic foreign object is absent on the transmission coil. The measured value is obtained by supplying electrical power to the transmission coil. If P_IN0 represents input power of the transmission coil, P_L0 represents output power of the reception coil, P_c1 represents copper loss of the transmission coil, and P_c2, represents copper loss of the reception coil, the detecting unit uses a value expressed by (P_IN0-P_L0-P_c1-P_c2) as the standard value and the measured value.

Claims

1. A contactless power transfer system for a movable object, comprising:

a power transmission coil installed on a ground side;

a power reception coil positioned opposite the power transmission coil across a gap, and installed on a movable object side, power being transferred from the power transmission coil to the power reception coil by electromagnetic induction; and

a foreign object detecting unit that calculates a difference between a standard value and a measured value, detects presence or absence of a metallic foreign object on the power transmission coil based on the difference, and outputs a foreign object detection signal when the metallic foreign object is detected, wherein

the standard value is obtained in advance by supplying electrical power for foreign object detection purpose to the power transmission coil in a state in which metallic foreign object is absent on the power transmission coil, and

the measured value is obtained by supplying the electrical power for foreign object detection purpose to the power transmission coil, and wherein

if P_IN0 represents an input power of the power transmission coil, P_L0 represents an output power of the power reception coil, P_c1 represents copper loss of the power transmission coil, and if P_c1 represents copper loss of the power reception coil, the foreign object detecting unit uses a value expressed by (P_IN0-P_L0-P_c1-P_c2) as the standard value and the measured value.

4. The contactless power transfer system for a movable object according to claim 1, wherein, when the electrical power for foreign object detection purpose is supplied to the power transmission coil, connection between the power reception coil and a rectifier following the power reception coil is disconnected.

8. The contactless power transfer system for a movable object according to claim 1, wherein the electrical power for foreign object detection purpose is less than or equal to 20% of a rated power-transfer power.

9. The contactless power transfer system for a movable object according to claim 1, further comprising a foreign object removing unit that removes, when the foreign object detecting unit detects a metallic foreign object, the metallic foreign object on the power transmission coil.

10. The contactless power transfer system for a movable object according to claim 9, wherein the foreign object removing unit includes:

a non-magnetic and non-conductive cover member that covers an upper face of the power transmission coil;

a pivoting unit that pivotally supports the cover member at an edge position of the power transmission coil so that the cover member is able to rotate by a predetermined angle around an axis line parallel to the upper face of the power transmission coil; and

a rotary drive unit that rotates, when a metallic foreign object is detected, the cover member by a predetermined angle around the axis line.

11. The contactless power transfer system for a movable object according to claim 10, wherein

the cover member is made of a plurality of divided cover members that dividedly covers the upper face of the power transmission coil,

the pivoting unit is provided to each of the divided cover members, and,

when a metallic foreign object is detected, the rotary drive unit rotates all of the divided cover members.

12. The contactless power transfer system for a movable object according to claim 9, wherein the foreign object removing unit includes an air compressor that blows, when a metallic foreign object is detected, high-speed air to an air gap formed between the power transmission coil and the power reception coil.

13. The contactless power transfer system for a movable object according to claim 9, wherein

the foreign object removing unit includes a resin belt conveyor and a pair of rollers,

the pair of rollers includes a driving roller and a driven roller that support the belt conveyor in a circularly-travelling manner,

the pair of rollers supports the belt conveyor so that one face of the circularly-travelling belt conveyor covers the upper face of the power transmission coil, and,

when a metallic foreign object is detected, the driving roller causes the belt conveyor to travel in a circular manner so that the face of the belt conveyor covering the upper face of the power transmission coil is renewed.

14. The contactless power transfer system for a movable object according to claim 9, wherein

the foreign object removing unit includes a wiper member and a wiper driving unit,

the wiper member wipes the upper face of the power transmission coil,

the wiper driving unit drives the wiper member, and,

when a metallic foreign object is detected, the wiper driving unit drives the wiper member so that the upper face of the transmission coil is wiped by the wiper member.

15. The contactless power transfer system for a movable object according to claim 1, wherein, based on the foreign object detection signal output by the foreign object detecting unit, supply of the electrical power for foreign object detection purpose to the power transmission coil is stopped, and a foreign object detection warning is displayed.

16. The contactless power transfer system for a movable object according to claim 15, wherein,

for each time when a preliminarily set time is elapsed, the electrical power for foreign object detection purpose is supplied to the power transmission coil to which supply of the electrical power for foreign object detection purpose has been stopped, and the foreign object detection operation is performed again, and,

when the foreign object detecting unit does not detect a metallic foreign object, electrical power for power transfer purpose is supplied to the power transmission coil.

17. The contactless power transfer system for a movable object according to claim 9, wherein,

the foreign object removing unit that has removed a metallic foreign object from the upper face of the power transmission coil notifies the foreign object detecting unit about removal,

the foreign object detecting unit receives a notification and performs detection for a metallic foreign object on the power transmission coil, and,

when no metallic foreign object is detected, electrical power for power transfer purpose is supplied to the power transmission coil.

2. (canceled)

3. A contactless power transfer system for a movable object, comprising:

a power transmission coil installed on a ground side;

a power reception coil positioned opposite the power transmission coil across a gap, and installed on a movable object side, power being transferred from the power transmission coil to the power reception coil by electromagnetic induction; and

a foreign object detecting unit that calculates a difference between a standard value and a measured value, detects presence or absence of a metallic foreign object on the power transmission coil based on the difference, and outputs a foreign object detection signal when the metallic foreign object is detected, wherein

the standard value is obtained in advance by supplying electrical power for foreign object detection purpose to the power transmission coil in a state in which metallic foreign object is absent on the power transmission coil, and

the measured value is obtained by supplying the electrical power for foreign object detection purpose to the power transmission coil, and wherein

if P_IN0 represents an input power of the power transmission coil, P_L0 represents an output power of the power reception coil, P_c1 represents copper loss of the power transmission coil, P_c2 represents copper loss of the power reception coil, P_f1 represents iron loss of the power transmission coil, and if P_c2 represents iron loss of the power reception coil, the foreign object detecting unit uses a value expressed by (P_IN0-P_L0-P_c1-P_c2-P_f1-P_f2) as the standard value and the measured value.

18. The contactless power transfer system for a movable object according to claim 3, wherein, when the electrical power for foreign object detection purpose is supplied to the power transmission coil, connection between the power reception coil and a rectifier following the power reception coil is disconnected.

19. The contactless power transfer system for a movable object according to claim 3, wherein the electrical power for foreign object detection purpose is less than or equal to 20% of a rated power-transfer power.

20. The contactless power transfer system for a movable object according to claim 3, further comprising a foreign object removing unit that removes, when the foreign object detecting unit detects a metallic foreign object, the metallic foreign object on the power transmission coil.

21. The contactless power transfer system for a movable object according to claim 20, wherein the foreign object removing unit includes:

a non-magnetic and non-conductive cover member that covers an upper face of the power transmission coil;

a pivoting unit that pivotally supports the cover member at an edge position of the power transmission coil so that the cover member is able to rotate by a predetermined angle around an axis line parallel to the upper face of the power transmission coil; and

a rotary drive unit that rotates, when a metallic foreign object is detected, the cover member by a predetermined angle around the axis line.

22. The contactless power transfer system for a movable object according to claim 21, wherein

the cover member is made of a plurality of divided cover members that dividedly covers the upper face of the power transmission coil,

the pivoting unit is provided to each of the divided cover members, and,

when a metallic foreign object is detected, the rotary drive unit rotates all of the divided cover members.

23. The contactless power transfer system for a movable object according to claim 20, wherein the foreign object removing unit includes an air compressor that blows, when a metallic foreign object is detected, high-speed air to an air gap formed between the power transmission coil and the power reception coil.

24. The contactless power transfer system for a movable object according to claim 20, wherein

the foreign object removing unit includes a resin belt conveyor and a pair of rollers,

the pair of rollers includes a driving roller and a driven roller that support the belt conveyor in a circularly-travelling manner,

the pair of rollers supports the belt conveyor so that one face of the circularly-travelling belt conveyor covers the upper face of the power transmission coil, and,

when a metallic foreign object is detected, the driving roller causes the belt conveyor to travel in a circular manner so that the face of the belt conveyor covering the upper face of the power transmission coil is renewed.

25. The contactless power transfer system for a movable object according to claim 20, wherein

the foreign object removing unit includes a wiper member and a wiper driving unit,

the wiper member wipes the upper face of the power transmission coil,

the wiper driving unit drives the wiper member, and,

when a metallic foreign object is detected, the wiper driving unit drives the wiper member so that the upper face of the transmission coil is wiped by the wiper member.

26. The contactless power transfer system for a movable object according to claim 3, wherein, based on the foreign object detection signal output by the foreign object detecting unit, supply of the electrical power for foreign object detection purpose to the power transmission coil is stopped, and a foreign object detection warning is displayed.

27. The contactless power transfer system for a movable object according to claim 26, wherein,

for each time when a preliminarily set time is elapsed, the electrical power for foreign object detection purpose is supplied to the power transmission coil to which supply of the electrical power for foreign object detection purpose has been stopped, and the foreign object detection operation is performed again, and,

when the foreign object detecting unit does not detect a metallic foreign object, electrical power for power transfer purpose is supplied to the power transmission coil.

28. The contactless power transfer system for a movable object according to claim 20, wherein,

the foreign object removing unit that has removed a metallic foreign object from the upper face of the power transmission coil notifies the foreign object detecting unit about removal,

the foreign object detecting unit receives a notification and performs detection for a metallic foreign object on the power transmission coil, and,

when no metallic foreign object is detected, electrical power for power transfer purpose is supplied to the power transmission coil.

5. A contactless power transfer system for a movable object, comprising:

a power transmission coil installed on a ground side;

a power reception coil positioned opposite the power transmission coil across a gap, and installed on a movable object side, power being transferred from the power transmission coil to the power reception coil by electromagnetic induction; and

a foreign object detecting unit that calculates a difference between a standard value and a measured value, detects presence or absence of a metallic foreign object on the power transmission coil based on the difference, and outputs a foreign object detection signal when the metallic foreign object is detected, wherein

the standard value is obtained in advance by supplying electrical power for foreign object detection purpose to the power transmission coil in a state in which metallic foreign object is absent on the power transmission coil, and

the measured value is obtained by supplying the electrical power for foreign object detection purpose to the power transmission coil, and wherein

the electrical power for foreign object detection purpose is supplied to the power transmission coil that is not positioned opposite the power reception coil, and,

if P_IN0 represents an input power of the power transmission coil and P_c1 represents copper loss of the power transmission coil, the foreign object detecting unit uses a value expressed by (P_IN0-P_c1) as the standard value and the measured value.

29. The contactless power transfer system for a movable object according to claim 5, wherein the electrical power for foreign object detection purpose is less than or equal to 20% of a rated power-transfer power.

30. The contactless power transfer system for a movable object according to claim 5, further comprising a foreign object removing unit that removes, when the foreign object detecting unit detects a metallic foreign object, the metallic foreign object on the power transmission coil.

31. The contactless power transfer system for a movable object according to claim 30, wherein the foreign object removing unit includes:

a non-magnetic and non-conductive cover member that covers an upper face of the power transmission coil;

a pivoting unit that pivotally supports the cover member at an edge position of the power transmission coil so that the cover member is able to rotate by a predetermined angle around an axis line parallel to the upper face of the power transmission coil; and

a rotary drive unit that rotates, when a metallic foreign object is detected, the cover member by a predetermined angle around the axis line.

32. The contactless power transfer system for a movable object according to claim 31, wherein

the cover member is made of a plurality of divided cover members that dividedly covers the upper face of the power transmission coil,

the pivoting unit is provided to each of the divided cover members, and,

when a metallic foreign object is detected, the rotary drive unit rotates all of the divided cover members.

33. The contactless power transfer system for a movable object according to claim 30, wherein the foreign object removing unit includes an air compressor that blows, when a metallic foreign object is detected, high-speed air to an air gap formed between the power transmission coil and the power reception coil.

34. The contactless power transfer system for a movable object according to claim 30, wherein

the foreign object removing unit includes a resin belt conveyor and a pair of rollers,

the pair of rollers includes a driving roller and a driven roller that support the belt conveyor in a circularly-travelling manner,

the pair of rollers supports the belt conveyor so that one face of the circularly-travelling belt conveyor covers the upper face of the power transmission coil, and,

when a metallic foreign object is detected, the driving roller causes the belt conveyor to travel in a circular manner so that the face of the belt conveyor covering the upper face of the power transmission coil is renewed.

35. The contactless power transfer system for a movable object according to claim 30, wherein

the foreign object removing unit includes a wiper member and a wiper driving unit,

the wiper member wipes the upper face of the power transmission coil,

the wiper driving unit drives the wiper member, and,

when a metallic foreign object is detected, the wiper driving unit drives the wiper member so that the upper face of the transmission coil is wiped by the wiper member.

36. The contactless power transfer system for a movable object according to claim 5, wherein, based on the foreign object detection signal output by the foreign object detecting unit, supply of the electrical power for foreign object detection purpose to the power transmission coil is stopped, and a foreign object detection warning is displayed.

37. The contactless power transfer system for a movable object according to claim 36, wherein,

for each time when a preliminarily set time is elapsed, the electrical power for foreign object detection purpose is supplied to the power transmission coil to which supply of the electrical power for foreign object detection purpose has been stopped, and the foreign object detection operation is performed again, and,

when the foreign object detecting unit does not detect a metallic foreign object, electrical power for power transfer purpose is supplied to the power transmission coil.

38. The contactless power transfer system for a movable object according to claim 37, wherein,

the foreign object removing unit that has removed a metallic foreign object from the upper face of the power transmission coil notifies the foreign object detecting unit about removal,

the foreign object detecting unit receives a notification and performs detection for a metallic foreign object on the power transmission coil, and,

when no metallic foreign object is detected, electrical power for power transfer purpose is supplied to the power transmission coil.

6. (canceled)

7. A contactless power transfer system for a movable object, comprising:

a power transmission coil installed on a ground side;

a power reception coil positioned opposite the power transmission coil across a gap, and installed on a movable object side, power being transferred from the power transmission coil to the power reception coil by electromagnetic induction; and

a foreign object detecting unit that calculates a difference between a standard value and a measured value, detects presence or absence of a metallic foreign object on the power transmission coil based on the difference, and outputs a foreign object detection signal when the metallic foreign object is detected, wherein

the standard value is obtained in advance by supplying electrical power for foreign object detection purpose to the power transmission coil in a state in which metallic foreign object is absent on the power transmission coil, and

the measured value is obtained by supplying the electrical power for foreign object detection purpose to the power transmission coil, and wherein

the electrical power for foreign object detection purpose is supplied to the power transmission coil that is not positioned opposite the power reception coil, and,

if P_IN0 represents an input power of the power transmission coil, P_c1 represents copper loss of the power transmission coil, and if P_f1 represents iron loss of the power transmission coil, the foreign object detecting unit uses a value expressed by (P_IN0-P_c1-P_f1) as the standard value and the measured value.

39. The contactless power transfer system for a movable object according to claim 7, wherein the electrical power for foreign object detection purpose is less than or equal to 20% of a rated power-transfer power.

40. The contactless power transfer system for a movable object according to claim 7, further comprising a foreign object removing unit that removes, when the foreign object detecting unit detects a metallic foreign object, the metallic foreign object on the power transmission coil.

41. The contactless power transfer system for a movable object according to claim 40, wherein the foreign object removing unit includes:

a non-magnetic and non-conductive cover member that covers an upper face of the power transmission coil;

a pivoting unit that pivotally supports the cover member at an edge position of the power transmission coil so that the cover member is able to rotate by a predetermined angle around an axis line parallel to the upper face of the power transmission coil; and

a rotary drive unit that rotates, when a metallic foreign object is detected, the cover member by a predetermined angle around the axis line.

42. The contactless power transfer system for a movable object according to claim 41, wherein

the cover member is made of a plurality of divided cover members that dividedly covers the upper face of the power transmission coil,

the pivoting unit is provided to each of the divided cover members, and,

when a metallic foreign object is detected, the rotary drive unit rotates all of the divided cover members.

43. The contactless power transfer system for a movable object according to claim 40, wherein the foreign object removing unit includes an air compressor that blows, when a metallic foreign object is detected, high-speed air to an air gap formed between the power transmission coil and the power reception coil.

44. The contactless power transfer system for a movable object according to claim 40, wherein

the foreign object removing unit includes a resin belt conveyor and a pair of rollers,

the pair of rollers includes a driving roller and a driven roller that support the belt conveyor in a circularly-travelling manner,

the pair of rollers supports the belt conveyor so that one face of the circularly-travelling belt conveyor covers the upper face of the power transmission coil, and,

when a metallic foreign object is detected, the driving roller causes the belt conveyor to travel in a circular manner so that the face of the belt conveyor covering the upper face of the power transmission coil is renewed.

45. The contactless power transfer system for a movable object according to claim 40, wherein

the foreign object removing unit includes a wiper member and a wiper driving unit,

the wiper member wipes the upper face of the power transmission coil,

the wiper driving unit drives the wiper member, and,

when a metallic foreign object is detected, the wiper driving unit drives the wiper member so that the upper face of the transmission coil is wiped by the wiper member.

46. The contactless power transfer system for a movable object according to claim 7, wherein, based on the foreign object detection signal output by the foreign object detecting unit, supply of the electrical power for foreign object detection purpose to the power transmission coil is stopped, and a foreign object detection warning is displayed.

47. The contactless power transfer system for a movable object according to claim 46, wherein,

for each time when a preliminarily set time is elapsed, the electrical power for foreign object detection purpose is supplied to the power transmission coil to which supply of the electrical power for foreign object detection purpose has been stopped, and the foreign object detection operation is performed again, and,

when the foreign object detecting unit does not detect a metallic foreign object, electrical power for power transfer purpose is supplied to the power transmission coil.

48. The contactless power transfer system for a movable object according to claim 40, wherein,

the foreign object removing unit that has removed a metallic foreign object from the upper face of the power transmission coil notifies the foreign object detecting unit about removal,

the foreign object detecting unit receives a notification and performs detection for a metallic foreign object on the power transmission coil, and,

when no metallic foreign object is detected, electrical power for power transfer purpose is supplied to the power transmission coil.