SYSTEMS AND METHODS FOR DIPOLE ENHANCED INDUCTIVE POWER TRANSFER

• US 20110304220A1
• Filed: 02/26/2010
• Published: 12/15/2011
• Est. Priority Date: 02/26/2009
• Status: Active Grant

• Current Assignee: University of British Columbia
• Original Assignee: University of British Columbia
• Inventors: Whitehead, Lorne A.
• Granted Patent: US 9,071,062 B2
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: H01F 2003/103 Magnetic circuits with permanent magnets
• CPC Class Codes: H01F 21/08 by varying the permeability of the core, e.g. by varying magnetic bias
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H04B 5/263 Multiple coils at either side

Abstract

An inductive power transfer apparatus is disclosed. A transmitter generates a first time varying magnetic field. A receiver is separated from the transmitter by a gap, but is located with the first time varying magnetic field. The receiver comprises: a conductor; and a receiver magnet located in the first time varying magnetic field and supported for movement in response to the first time varying magnetic field. The conductor and receiver are positioned relative to one another such that movement of the receiver magnet creates a second time-varying magnetic field in a vicinity of the conductor to thereby induce current in the conductor.

Claims

1. A receiver for extracting energy from a first time-varying magnetic field, the receiver comprising:

a conductor; and

a receiver magnet located in the first time-varying magnetic field and supported for movement in response to the first time-varying magnetic field;

wherein the conductor and receiver magnet are positioned relative to one another such that movement of the receiver magnet creates a second time-varying magnetic field in a vicinity of the conductor to thereby induce current in the conductor.

2. A receiver according to claim 1 wherein the conductor comprises one or more coils, each coil comprising one or more conductive turns.

6. A receiver according to claim 1 wherein the receiver magnet is supported for oscillatory motion about an oscillation axis in response to the first time-varying magnetic field by one or more mounts, each of the one or more mounts comprising one or more bias elements which deform as the receiver magnet moves about the oscillation axis away from an ambient orientation and which exert restorative torque on the receiver magnet to return the receiver magnet to the ambient orientation.

7. A receiver according to claim 1 wherein the receiver magnet is supported for rotational motion about a rotation axis in response to the first time-varying magnetic field.

8. A receiver according to claim 1 wherein the first time-varying magnetic field is periodic and the receiver magnet experiences a resultant periodic torque, the torque causing periodic motion of the receiver magnet with a period that matches a period of the first time-varying magnetic field.

10. A receiver according to claim 1 wherein the receiver magnet comprises a substantially dipole permanent magnet.

11. A receiver according to claim 6 wherein the receiver magnet comprises a substantially dipole permanent magnet and the receiver magnet has a dipole vector that is orthogonal ±

20°

to the oscillation axis of the receiver magnet.

13. A receiver according to claim 7 wherein the receiver magnet comprises a substantially dipole permanent magnet and the receiver magnet has a dipole vector that is orthogonal ±

20°

to the rotation axis of the receiver magnet.

18. A receiver according to claim 1 comprising one or more supports for moveably supporting the receiver magnet, the one or more supports comprising one or more of:

ceramic ball bearings; and

jewel bearings.

19. A receiver according to claim 1 comprising one or more sensors for sensing one or more phenomena representative of a slip angle, the slip angle representing a phase difference between periodic variation of the first time-varying magnetic field and corresponding periodic motion of the receiver magnet.

20. A receiver according to claim 19 comprising a controller connected to receive one or more signals from the one or more slip angle sensors, and configured to estimate the slip angle and to adjust a coupling between the conductor and an electrical load based on the estimated slip angle to thereby maintain a slip angle for which there is positive work produced on the load.

22. A receiver according to claim 1 comprising one or more sensors for sensing one or more phenomena representative of an orientation angle of the receiver magnet relative to the first time-varying magnetic field.

23. A receiver according to claim 22 comprising a controller connected to receive one or more signals from the one or more orientation sensors and configured to estimate the orientation angle of the receiver magnet relative to the first time-varying magnetic field and to emit an output signal if the estimated orientation angle is greater than a threshold.

25. A receiver according to claim 1 comprising one or more sensors for sensing one or more phenomena representative of an intensity of the first-time varying magnetic field.

26. A receiver according to claim 25 comprising a controller connected to receive one or more signals from the one or more intensity sensors and configured to estimate the intensity of the first-time varying magnetic field and to emit an output signal if the estimated intensity is one or more of:

greater than a first threshold; and

less than a second threshold.

29. A receiver according to claim 1 wherein the conductor is electrically connected to a battery and wherein the receiver comprises one or more sensors for sensing one or more phenomena representing a charge of the battery.

31. A receiver according to claim 29 comprising a controller connected to receive one or more signals from the one or more charge sensors and configured to estimate the charge of the battery and to emit an output signal if the estimated charge is greater than or equal to a threshold.

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32. A power transfer apparatus comprising:

a transmitter for generating a first time varying magnetic field; and

a receiver separated from the transmitter by a gap, the receiver comprising;

a conductor; and

a receiver magnet located in the first time varying magnetic field and supported for movement in response to the first time varying magnetic field;

wherein the conductor and receiver magnet are positioned relative to one another such that movement of the receiver magnet creates a second time-varying magnetic field in a vicinity of the conductor to thereby induce current in the conductor.

33. An apparatus according to claim 32 wherein the receiver magnet is supported for rotational motion about a rotation axis in response to the first time-varying magnetic field and wherein a ratio of the gap to a maximum radius of motion of the receiver magnet is greater than or equal to 1.

36. An apparatus according to claim 32 wherein the receiver magnet is supported for oscillatory motion about an oscillation axis in response to the first time varying magnetic field and wherein a ratio of the gap to a maximum radius of motion of the receiver magnet is greater than or equal to 1.

39. An apparatus according to claim 32 wherein a non-magnetic barrier is located in the gap between the transmitter and receiver.

41. An apparatus according to claim 32 wherein the transmitter comprises a transmitter magnet supported for movement therein, the motion of the transmitter magnet creating the first time-varying magnetic field.

42. An apparatus according to claim 41 wherein the transmitter magnet is supported for oscillatory motion about an oscillation axis by one or more mounts, each of the one or more mounts comprising one or more bias elements which deform as the transmitter magnet moves about the oscillation axis away from an ambient orientation and which exert restorative torque on the transmitter magnet to return the transmitter magnet to the ambient orientation.

43. An apparatus according to claim 42 wherein the receiver magnet is supported for oscillatory motion about an oscillation axis in response to the first time-varying magnetic field by one or more mounts, each of the one or more mounts comprising one or more bias elements which deform as the receiver magnet moves about the oscillation axis away from an ambient orientation and which exert restorative torque on the receiver magnet to return the receiver magnet to the ambient orientation and wherein the oscillation axes of transmitter magnet and receiver magnet are substantially parallel ±

20°

.

45. An apparatus according to claim 41 wherein the transmitter magnet is supported for rotational motion about a rotation axis.

46. An apparatus according to claim 45 wherein the receiver magnet is supported for rotational motion about a rotation axis in response to the first time-varying magnetic field and wherein the rotation axes of transmitter magnet and receiver magnet are substantially parallel ±

20°

.

48. An apparatus according to claim 41 wherein the transmitter magnet comprises a substantially dipole permanent magnet.

49. An apparatus according to claim 42 wherein the transmitter magnet comprises a substantially dipole magnet having a magnetic dipole vector that is substantially orthogonal ±

20°

the oscillation axis of the transmitter magnet.

50. An apparatus according to claim 45 wherein the transmitter magnet comprises a substantially dipole magnet having a magnetic dipole vector that is substantially orthogonal ±

20°

to the rotation axis of the transmitter magnet.

52. An apparatus according to claim 41 comprising one or more supports for moveably supporting the transmitter magnet, the one or more supports comprising one or more of:

ceramic ball bearings; and

jewel bearings.

53. An apparatus according to claim 41 wherein the transmitter comprises one or more sensors for sensing one or more phenomena representative of a slip angle, the slip angle representing a phase difference between periodic movement of the transmitter magnet and corresponding periodic motion of the receiver magnet.

54. An apparatus according to claim 53 comprising a controller connected to receive one or more signals from the one or more slip angle sensors and configured to estimate the slip angle and to control movement of the transmitter magnet in response to the estimated slip angle and to thereby maintain a slip angle for which positive work is transmitted to a load electrically connected to the conductor.

56. An apparatus according to claim 41 wherein transmitter comprises one or more sensors for sensing one or more phenomena representative of an orientation angle of the receiver magnet relative to the transmitter magnet.

57. An apparatus according to claim 56 comprising a controller connected to receive one or more signals from the one or more orientation sensors and configured to estimate the orientation angle of the receiver magnet relative to the transmitter magnet and to emit an output signal if the estimated orientation angle is greater than a threshold.

59. An apparatus according to claim 41 wherein the transmitter comprises one or more sensors for sensing one or more phenomena representative of an intensity of the second time-varying magnetic field created by the receiver magnet.

60. An apparatus according to claim 59 comprising a controller connected to receive one or more signals from the one or more intensity sensors and configured to determine the intensity of the second time-varying magnetic field and to emit an output signal if the estimated intensity is one or more of:

greater than a first threshold; and

less than a second threshold.

62. An apparatus according to claim 32 comprising one or more RFID proximity sensors, the RFID proximity sensors located in one or more of:

the transmitter and the receiver.

64. An apparatus according to claim 32 wherein the conductor is electrically connected to a battery and wherein the transmitter comprises one or more sensors for sensing one or more phenomena representing a charge of the battery.

65. An apparatus according to claim 64 wherein the one or more charge sensors detect power associated with generating the first time varying magnetic field.

67. An apparatus according to claim 65 comprising a controller connected to receive one or more signals from the one or more charge sensors and configured to estimate the charge of the battery and to emit an output signal if the estimated charge is greater than or equal to a threshold.

80. An apparatus according to claim 39 wherein the non-magnetic barrier comprises a metallic barrier.

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68. A power transfer apparatus comprising:

a transmitter for generating a first time varying magnetic field;

a receiver separated from the transmitter by a gap, the receiver comprising a moveable receiver magnet located in first time varying magnetic field; and

means for converting mechanical energy of the receiver magnet'"'"'s motion into another form of energy;

wherein the first time varying magnetic field applies to the receiver magnet a time varying torque which causes the receiver magnet to move under the influence of the first time varying magnetic field;

wherein the receiver magnet is supported for at least one of;

rotational motion about a rotation axis and oscillatory motion about an oscillation axis and wherein a ratio of the gap to a maximum radius of motion of the receiver magnet is greater than or equal to 1.

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71. A method delivering charge to an electrical load, the method comprising:

locating a receiver magnet in a first time varying magnetic field;

supporting the receiver magnet for movement in response to the first time varying magnetic field;

positioning a coil comprising one or more turns relative to the receiver such that movement of the receiver magnet creates a second time varying magnetic field in a vicinity of the coil to thereby induce current in the coil; and

electrically connecting the coil to the load.

73. A method according to any claim 71 comprising supporting the receiver magnet for oscillatory motion about an oscillation axis in response to the first time-varying magnetic field using one or more mounts, each of the one or more mounts comprising one or more bias elements which deform as the receiver magnet moves about the oscillation axis away from an ambient orientation and which exert restorative torque on the receiver magnet to return the receiver magnet to the ambient orientation.

74. A method according to any claim 71 comprising supporting the receiver magnet for rotational motion about a rotation axis in response to the first time varying magnetic field.

75. A method according to any claim 71 wherein the first time-varying magnetic field is periodic and the receiver magnet experiences a resultant periodic torque, the torque causing periodic motion of the receiver magnet with a period that matches a period of the first time-varying magnetic field.

77. A method according to claim 71 wherein the load comprises a battery and the method comprises:

detecting a charge of the battery; and

decoupling the electrical connection between the coil and the load when the charge of the battery is greater than a threshold.

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