MAGNETOMECHANICAL TRANSDUCER, AND APPARATUS AND METHODS FOR HARVESTING ENERGY

• US 20080143195A1
• Filed: 10/19/2007
• Published: 06/19/2008
• Est. Priority Date: 10/19/2006
• Status: Active Grant

• Current Assignee: Boise State University
• Original Assignee: Boise State University
• Inventors: HAMPIKIAN, GREG, MULLNER, PETER
• Granted Patent: US 8,008,816 B2
• Time in Patent Office: Days
• US Class Current: 310/26
• CPC Class Codes: H10N 35/00 Magnetostrictive devices integrated devices or assemblies of multiple devices H10N39/00

Abstract

A magnetomechanical transducer, and apparatus and methods using said magnetomechanical transducer, extract electrical power from any motion, including random motion, cyclic, and vibrational motion. The motion is transferred to linear motion through a mechanical connecting device to the magnetomechanical coupler, which comprises a magnetoplastic and/or magnetoelastic material that transduces the linear motion into a change of magnetic field, via twin boundary deformation. A bias magnetic field assures a net change of magnetization during said deformation. A further transducer, e.g. a coil or a Hall element, couples the magnetic field change to an electrical output. A restoring field or device, for example the bias magnetic field or a device that produces strain in a reverse direction, resets the magnetomechanical transducer to its initial state. The magnetomechanical transducer may be provided in microgenerators that capture kinetic energy and convert it to electrical power. Such microgenerators may be connected in series or parallel, may be combined with solar cells, and may be used to capture energy from passive motion such as walking, and naturally-occurring random, cyclic or vibrations motion such as that produced by wind or waves acting upon objects. The random, cyclic, or vibrational motion of any object may be transmitted to the magnetoplastic transducer through a mechanical connector.

Claims

1. A system of generating electrical power from a motion, the system comprising at least two transducers comprising a first transducer and a second transducer, and a magnetic bias, wherein the first transducer comprises magnetoplastic and/or magnetoelastic material, wherein, when said first transducer is strained by application of force resulting from said motion, twin boundaries in said magnetoplastic and/or magnetoelastic material deform and/or move to produce a change in magnetization of the first transducer, and wherein said change in magnetization generates electrical energy in the second transducer for power generation.

2. A system as in claim 1, wherein said magnetoplastic and/or magnetelastic material resides in an initial state prior to strain by application of said force, and wherein the system further comprises a restoring device adapted to reset said first transducer to the initial state upon cessation of said application of force.

3. A system as in claim 2, wherein said restoring device is said magnetic bias.

4. A system as in claim 1, wherein the motion is a random motion of an object, wherein the force resulting from the motion of the object is transmitted to the magnetoplastic and/or magnetoelastic material through a mechanical connector.

5. A system as in claim 2, wherein the motion is a random motion of an object, wherein the force resulting from the motion of the object is transmitted to the magnetoplastic and/or magnetoelastic material through a mechanical connector.

6. A system as in claim 1, wherein said second transducer is a conducting coil.

7. A system as in claim 1, wherein said second transducer is a Hall element.

8. A system as in claim 1, wherein said second transducer is a device transforming a change of magnetic field into an electrical voltage output.

9. A system as in claim 1, wherein said second transducer is a device transforming a change of magnetic field into an electrical current output.

10. A combination of a plurality of the systems of claim 1 linked in series.

11. A combination of a plurality of the systems of claim 1 linked in parallel.

12. A system as in claim 1, wherein magnetic bias is provided by a device selected from the group consisting of:

an electromagnet, a permanent magnet, and a combination thereof.

13. A system as in claim 1, wherein said first transducer is provided as a thin film on a support.

14. A system as in claim 1, wherein said first transducer is provided as a free-standing or partially free-standing thin film.

15. A system as in claim 1, wherein the first transducer comprises material selected from the group consisting of:

Heusler shape-memory alloy, non-Heusler ferromagnetic shape-memory alloy, antiferromagnetic shape-memory alloy, non-shape-memory magnetoplastic alloy, Ni₂MnGa, Dy, α

-Fe, Co—

Ni, τ

-MnAl—

C, L1₀FePd, L1₀CoPt, L1₀FePt, Ni₂MnGa, Co₂NiGa, Ni₂MnAl, Ni₂FeGa, Fe₃Pd, Fe—

Pd—

PT, γ

-Mn—

Fe—

Cu, Ni₅₁Mn₂₈Ga₂₁, Ni—

Mn—

Ga alloys, Ni—

Mn—

Ga ferromagnetic martensite, and combinations thereof.

16. An electrical power generation system for harvesting energy from motion of wind, water, moving objects or moving humans, the system comprising at least one magnetomechanical device comprising:

a magnet providing a magnetic bias, a first transducer comprising material that, upon deformation of the material by an applied force from said motion, produces a net change in magnetization relative to said magnetic bias, by twin boundary rearrangement, and a second transducer that transduces magnetization to electrical energy.

17. An electrical power generation system as in claim 16, wherein said material is a magnetoplastic and/or magnetelastic material that resides in an initial state prior to deformation by said applied force, and wherein the power generation system further comprises a restoring device adapted to reset said material to said initial state after said deformation.

18. An electrical power generation system as in claim 17, said magnet is said restoring device in addition to providing said magnetic bias.

19. An electrical power generation system as in claim 16, wherein the applied force is transferred to said material by a mechanical connector.

20. An electrical power generation system as in claim 16, wherein said applied force is from motion of an object in water.

21. An electrical power generation system as in claim 16, wherein said applied force is from motion of an object in wind.

22. An electrical power generation system as in claim 16, wherein said applied force is from motion of a machine.

23. An electrical power generation system as in claim 16, wherein the motion is selected from the group consisting of:

random, cyclic, and vibrational motion transferred to said material of the first transducer by a mechanical connector.

24. An electrical power generation system as in claim 16, wherein said second transducer is a conducting coil.

25. An electrical power generation system as in claim 16, wherein said second transducer is a Hall element.

26. An electrical power generation system as in claim 16, wherein said second transducer is a device transforming said net change of magnetization into an electrical voltage output.

27. An electrical power generation system as in claim 16, wherein said second transducer is a device transforming said net change of magnetization into an electrical current output.

28. An electrical power generation system comprising a plurality of the magnetomechanical devices of claim 16 linked in series.

29. An electrical power generation system comprising a plurality of the magnetomechanical devices of claim 16 linked in parallel.

30. An electrical power generation system as in claim 16, wherein the magnet is selected from the group consisting of:

an electromagnet, a permanent magnet, and a combination thereof.

31. An electrical power generation system as in claim 16, wherein said first transducer is provided as a thin film on a support.

32. An electrical power generation system as in claim 16, wherein said first transducer is provided as a free-standing or partially free-standing thin film.

33. An electrical power generation system as in claim 16, wherein the first transducer comprises material selected from the group consisting of:

Heusler shape-memory alloy, non-Heusler ferromagnetic shape-memory alloy, antiferromagnetic shape-memory alloy, non-shape-memory magnetoplastic alloy, Ni₂MnGa, Dy, α

-Fe, Co—

Ni, τ

-MnAl—

C, L1₀FePd, L1₀CoPt, L1₀FePt, Ni₂MnGa, Co₂NiGa, Ni₂MnAl, Ni₂FeGa, Fe₃Pd, Fe—

Pd—

PT, γ

-Mn—

Fe—

Cu, Ni₅₁Mn₂₈Ga₂₁, Ni—

Mn—

Ga alloys, Ni—

Mn—

Ga ferromagnetic martensite, and combinations thereof.

41. A method as in claim 34, comprising linking a plurality of the generators of claim 31 in series to extract electrical energy from all of said plurality of generators.

42. A method as in claim 34, comprising linking a plurality of the generators of claim 31 in parallel to extract electrical energy from all of said plurality of generators.

34. A method of generating electrical power from passive motion, the method comprising:

providing a generator comprising at least two transducers and a device producing a magnetic bias, said at least two transducers including a first transducer that comprises magnetoplastic and/or magnetoelastic material;

applying a force, derived from motion of an object or of a machine, to said first transducer to strain the first transducer, whereby said straining causes twin boundary deformation and/or in said magnetoplastic and/or magnetoelastic material that produces a change in magnetization;

providing a second transducer near said first transducer, wherein said second transducer transduces said change in magnetization to electrical current or voltage for electrical power production.

35. A method as in claim 34, wherein the second transducer comprises a conducting coil, wherein the first transducer has an initial state prior to said applying of force, and wherein the method further comprises said device producing the magnetic bias performing a two-fold function of inducing voltage in the coil for extraction of electrical power that is produced by a net change in magnetization by said deformation of the twin boundaries, and also of resetting said first transducer to said initial state.

36. A method as in claim 34, wherein said motion is selected from a group consisting of:

motion of an object in water, motion of an object in wind, motion of an item of human clothing, motion of footwear, motion of particles, motion of a fluid, and motion of a solid.

37. A method as in claim 34, wherein the applied force is transferred to said material by a mechanical connector.

38. A method as in claim 34, wherein the motion is selected from the group consisting of:

random, cyclic, and vibrational motion transferred to said material of the first transducer by a mechanical connector.

39. A method as in claim 34, wherein said second transducer is a conducting coil.

40. A method as in claim 34, wherein said second transducer is a Hall element.

43. A method as in claim 34, wherein the device producing said magnetic bias is selected from the group consisting of:

an electromagnet, a permanent magnet, and a combination thereof.

44. A method as in claim 34, wherein said first transducer is formed by providing a thin film of magnetoplastic and/or magnetoelastic material on a support in the vicinity of a thin film conducting coil.