WO2012024000A1 - Machine permettant de collecter l'énergie des vagues dotée d'une performance améliorée - Google Patents

Machine permettant de collecter l'énergie des vagues dotée d'une performance améliorée Download PDF

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Publication number
WO2012024000A1
WO2012024000A1 PCT/US2011/030977 US2011030977W WO2012024000A1 WO 2012024000 A1 WO2012024000 A1 WO 2012024000A1 US 2011030977 W US2011030977 W US 2011030977W WO 2012024000 A1 WO2012024000 A1 WO 2012024000A1
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WO
WIPO (PCT)
Prior art keywords
magnetostrictive
stressed
magnetostrictive core
change
core
Prior art date
Application number
PCT/US2011/030977
Other languages
English (en)
Inventor
Balakrishnan Nair
Original Assignee
Oscilla Power Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US13/016,828 external-priority patent/US8378512B2/en
Application filed by Oscilla Power Inc. filed Critical Oscilla Power Inc.
Publication of WO2012024000A1 publication Critical patent/WO2012024000A1/fr

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03B—MACHINES OR ENGINES FOR LIQUIDS
    • F03B13/00—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates
    • F03B13/12—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy
    • F03B13/14—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy using wave energy
    • F03B13/16—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy using wave energy using the relative movement between a wave-operated member, i.e. a "wom" and another member, i.e. a reaction member or "rem"
    • F03B13/18—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy using wave energy using the relative movement between a wave-operated member, i.e. a "wom" and another member, i.e. a reaction member or "rem" where the other member, i.e. rem is fixed, at least at one point, with respect to the sea bed or shore
    • F03B13/1885—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy using wave energy using the relative movement between a wave-operated member, i.e. a "wom" and another member, i.e. a reaction member or "rem" where the other member, i.e. rem is fixed, at least at one point, with respect to the sea bed or shore and the wom is tied to the rem
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
    • H02K7/18—Structural association of electric generators with mechanical driving motors, e.g. with turbines
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K99/00—Subject matter not provided for in other groups of this subclass
    • H02K99/10—Generators
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N35/00—Magnetostrictive devices
    • H10N35/101—Magnetostrictive devices with mechanical input and electrical output, e.g. generators, sensors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
    • F05B2220/00—Application
    • F05B2220/70—Application in combination with
    • F05B2220/706—Application in combination with an electrical generator
    • F05B2220/707—Application in combination with an electrical generator of the linear type
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
    • H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
    • H01F1/147—Alloys characterised by their composition
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/30—Energy from the sea, e.g. using wave energy or salinity gradient

Definitions

  • the apparatus is an apparatus for harvesting electrical power from water mechanical energy
  • the apparatus including: a buoy or other water flotation device connected to an anchor by a tether and a magnetostrictive component having an internal pre-stressed magnetostrictive core that experiences at least a part of load changes experienced by the tether.
  • the magnetic property of the magnetostrictive core is configured to change with changes in stress within the magnetostrictive core along at least one direction within the magnetostrictive component.
  • the hydrodynamic energy acting on the buoy or other water flotation device results in changes in force within the tether, which in turn changes the stress within the
  • the magnetostrictive core and consequently changes a magnetic property.
  • the magnetostrictive component is also configured such that the change in the magnetic property will result in a change in magnetic flux, which change can be used to generate electrical power.
  • the water flotation device is a buoy.
  • the magnetic property is a magnetic permeability of a magnetostrictive component.
  • the magnetic property is a magnetic flux density of a magnetostrictive component.
  • the electrically conductive coil is a polymer-coated electrically conductive coil surrounding the magnetostrictive component. Other embodiments of the apparatus are also described.
  • the method is a method for harvesting electrical power from water mechanical energy.
  • the method includes: tethering a water flotation device to an anchor by a tether, wherein the tether comprises a magnetostrictive component, the magnetostrictive component comprising a pre- stressed magnetostrictive core, wherein a magnetic property of the magnetostrictive core is configured to change with changes in stress within the magnetostrictive core along at least one direction within the magnetostrictive component.
  • the method also includes using change in magnetic flux resulting from the change in magnetic property, the change in magnetic property resulting from applied force changes caused by the interaction of a wave environment with the water flotation device.
  • the method also includes generating electrical power using the change in the magnetic flux.
  • the force changes caused by the interaction of a wave environment with the water flotation device are caused by caused by wave motion or wave height changes near the flotation device. Other embodiments of the method are also described.
  • Fig. 1 depicts a schematic diagram of one embodiment of a wave energy harvester.
  • Fig. 2 depicts a schematic diagram of one embodiment of dimensions of a magnetostrictive material and a graph diagram of its associated magnetic field.
  • Fig. 3 depicts a graph diagram of one embodiment of a comparison of magneto- mechanical coupling coefficients for various magnetostrictive materials.
  • Fig. 4 depicts a graph diagram of one embodiment of magnetic
  • Fig. 5 depicts a graph diagram of one embodiment of an effect of bias magnetic fields and compressive stress on a magnetostrictive material.
  • FIG. 6 depicts a schematic diagram of one embodiment of a pre-compression loading fixture.
  • Fig.7 depicts a schematic diagram of one embodiment of magnetic domain orientation in a magnetostrictive component under various stresses/magnetic field configurations.
  • Fig. 8 depicts a flow diagram of a method for harvesting electrical power from water mechanical energy.
  • Embodiments describe a wave energy harvesting system utilizing magnetostrictive materials that can enable highly cost-efficient energy harvesting from ocean waves, or other wave environment, while providing extremely good durability and reliability.
  • Embodiments also relate to a method and device for harvesting ocean wave energy that has the potential to deliver energy that is equal to or lower in cost than coal based power generation without subsidies or incentives. The method involves converting the mechanical energy of oscillating ocean waves into magnetic and then electrical energy using magnetostrictive materials.
  • a magnetostrictive material may be considered to be any material that can be designed or configured such that a change in applied stress can result in a change in the magnetic flux and/or magnetic field (the B -field) within the material.
  • WEH wave energy harvester
  • Another embodiment of the wave energy harvester (“WEH”) may have a significant benefit on the ocean energy landscape due to its unique combination of low capital/maintenance costs, ruggedness and reliability relative to competing technologies and ability to function well in low to moderate wave-height locations.
  • embodiments described herein include the first known ocean device that uses advanced materials as a substitute for moving parts, thereby minimizing one of the main engineering challenges in the ocean environment. While detailed power and cost modeling indicates that a device using magnetostrictive alloys such as iron-aluminum can be competitive with coal based power generation, significant improvement may be achieved by identifying and implementing specific design
  • the WEH is a device that captures the energy of oscillations in ocean waves and converts this energy to electrical energy.
  • Fig. 1 depicts a schematic diagram of one embodiment of a WEH 100, which may include a plurality of WEH devices.
  • Each WEH device includes a buoy 102 or other water flotation device attached to a tether 104 that is connected to an anchor on the sea floor as shown in Figure 1(a).
  • the tether 104 which is anchored to the seafloor using heavy weights and/or concrete (or other fastening mechanism) as anchors 106, may include one or more magnetostrictive components 108 (shown as "Power Generation Cells" in Fig.
  • the water flotation device is inside an oscillating water column.
  • the magnetostrictive components 108 may include magnetostrictive cores 110 wound with polymer (e.g. Teflon,
  • magnetostrictive cores 110 When a strain is imposed on magnetostrictive cores 110, it results in a change in a magnetic property of the magnetostrictive core 110. Such magnetic properties include the core's magnetization (or flux density) and the associated magnetic field (See Figure 2).
  • the magnetostrictive elements are encased in structural casings 116 that are corrosion-resistant and water-tight, but allow for the majority of the tether load to be transferred to the magnetostrictive core 110 and also allow for water tight electrical connections.
  • Each WEH device may be electrically connected to an electrical energy storage device 115. The electrical energy may be transformed or modified in any way, or may be transmitted to locations or devices.
  • Fig. 2 depicts a schematic diagram of one embodiment of dimensions 200 of a magnetostrictive material and a graph diagram of its associated magnetic field, according to the strain on the device.
  • Fig. 2(a) illustrates a range of dimensions 200 that a
  • magnetostrictive material may experience when a magnetic field 204 is applied to the material 202.
  • Fig. 2(b) is a graph 210 that illustrates a dependence of magnetostriction strain 212 on the applied magnetic field 204 of a particular magnetostrictive material.
  • the WEH's buoys 102 are designed such that their vertical length exceeds the expected amplitude of oscillations of normal wave motion expected at the geographic location of interest.
  • the WEH 100 may also be designed such that even as a wave is at its trough, the submerged height of the buoy is more than what it would have been if the buoy 102 was not tethered to the ocean floor.
  • the buoy 102 is always partially submerged whether it is at the crest or the trough of a wave. This ensures a tensile load on the magnetostrictive components 108 through the entire range of motion of the oscillating buoy 102.
  • the geometry outlined here causes the line tension in the tether 104 to be a strong function of the wave amplitude.
  • the passing wave is at its crest, more of the buoy 102 is submerged in water resulting in a greater tensile load on the magnetostrictive component 108.
  • the passing wave is at its trough, less of the buoy is submerged resulting in a lower tensile load on the magnetostrictive component 108.
  • the geometry of the individual magnetostrictive cores 110 is specified such that for a given buoy 102, the expected loads generated will result in strains that are below the saturation magnetostriction.
  • the extension of the magnetostrictive element follows a similar oscillation, resulting in a constantly changing magnetic flux density along the length of the magnetostrictive element.
  • This constantly changing magnetic flux density may be used to induce voltage/current in the copper coil 112.
  • One embodiment of the WEH 100 has at least three features that give it the potential to be a breakthrough in ocean power (although other embodiments may have less than all of the listed features):
  • corrosion or salt spray deposition can dramatically increase the friction and reduce the effectiveness of these components.
  • the technology is clean and creates electricity from ocean waves without consuming any carbonaceous fuels or generating any harmful pollutants. Even compared with other technologies for harvesting ocean power, the lack of moving parts and joints that require lubrication that may leak and pollute the oceans, this technology is exceptionally clean and environmentally friendly. The substitution of the energy generated by these approaches over fossil fuels will reduce green house gases and pollutants without any undesirable side-effects or compromises. Finally, the technology is friendly to marine life as the structures will not result in any impediment to natural migration patterns or affect sea-life in any significant way.
  • Some embodiments may also be used in compression.
  • the application of a compressive stress can reduce the magnetic flux in the orientation of the applied stress and the relieving of the compressive stress results in an increase in flux density.
  • the improvements outlined herein can further reduce WEH 100 system costs and increase system performance.
  • embodiments of the apparatus focus on improving the power density of low-cost magnetostrictive devices, through specific materials, component design and/or manufacturing enhancements, which can significantly reduce electricity costs.
  • Embodiments of the apparatus cover any device or method for harvesting or generating electric power that incorporates a magnetostrictive component 108, which includes a component containing a material whose magnetic properties change as a function of applied stress at least along one direction within the material.
  • a magnetostrictive component 108 covers any device or method for harvesting or generating electric power from the ocean that incorporates a magnetostrictive component 108, which includes a component containing a material whose magnetic properties change as a function of applied stress at least along one direction within the material.
  • Another embodiment includes a device or method for causing a periodic change in stress/strain in the magnetostrictive component 108 by coupling it to a buoy 102.
  • Magnetic properties include, but are not limited to, saturation magnetization, derivative of
  • This disclosure also covers processes, designs and materials that are intended to create states of pre-stress and/or pre-strain and/or magnetic bias within the
  • magnetostrictive component states of pre-stress and/or pre-strain and or magnetic bias may either be created internal to the magnetostrictive material during materials processing, or be caused in the material by mechanically or magnetically coupling with secondary components.
  • Magnetostrictive materials have primarily been used for actuator applications, and so far most of the efforts by researchers who study magnetostriction tend to focus largely on this application. Since the primary objective of an actuator is to deliver displacement against a load, the key requirement for these applications is a high saturation magnetization. This need drove the development of new exotic materials such as terbium alloys (e.g.
  • Terfenol-D that had saturation magnetizations of up to 2000 ppm.
  • the saturation magnetization strain is not a key parameter for energy harvesting applications. More important are parameters such as magneto-mechanical coupling coefficients (a measure of the energy that can be converted from magnetic energy to mechanical energy and vice versa), and the maximum magnetization change under applied tensile stress.
  • inexpensive "low performance" magnetostrictive materials such as iron aluminum alloys are more than sufficient to generate significant utility scale energy.
  • Iron-aluminum alloys were first explored as magnetic alloys in the 1950s - while they have moderate saturation magnetostriction values (100-140 ppm), their magneto- mechanical coupling can approach that of iron-gallium and values as high as 13.7 Mega- Joules/m3 have been measured for Fe-16 Al (See Figure 3).
  • Fig. 3 depicts a graph diagram of one embodiment of a comparison 300 of magneto-mechanical coupling coefficients for various magnetostrictive materials. This is a measure of the maximum energy that can be converted from magnetic to mechanical and vice-versa in one stress/strain cycle.
  • Fig. 4 depicts a graph diagram of one embodiment of magnetic and magnetostrictive properties 400 of Alfenol.
  • Possible criteria for material selection include the following:
  • the material should possess low hysteresis in the strain-magnetization curve.
  • the low hysteresis will result in low magnetomechanical coupling losses, again resulting in improved energy efficiency.
  • the material should have a high internal resistance.
  • a high internal resistance of the alloy results in minimization of eddy currents within the magnetostrictive components and resulting heat generation/energy loss.
  • the material should be of very low cost (cents/kWh) and therefore exotic/rare and high-cost alloying elements may be avoided.
  • the material should be of low weight (cents/kg) to help reduce installation costs.
  • Gallium, terbium, or dysprosium doping may or may not be attractive for bulk applications where several tons of material will be needed for MW scale energy production. Alloying with trace elements such as Co, Mn, W and Mo to target three phase alloy compositions with small additions of these metals (under 20 atomic %, and preferably under 5 atomic %) into the Fe-Al system has shown promising improvements in various properties as indicated below:
  • Co - Cobalt alloying of Fe or Fe-Al may improve magnetomechanical coupling
  • Mn - Addition of Mn has been shown to increase the electrical resistivity of Fe-Ga alloys without significant magnetostriction deterioration. A higher electrical resistivity can help to minimize eddy current losses in the magnetostrictive material and increase energy efficiency.
  • Fe-Al-Mo alloys have been shown to be strong and ductile, while possessing magnetostrictive properties.
  • W - Fe-Al-W alloys have been shown to be strong and ductile, while possessing magnetostrictive properties.
  • Fig. 5 depicts a graph diagram of one embodiment of an effect 500 of bias magnetic fields and compressive stress on a magnetostrictive material.
  • the application of a compressive stress reduces its magnetic permeability in the direction of the applied compressive stress.
  • the application of a compressive pre- stress impacts the magnetic permeability, and therefore the magnetic flux density (B) within the alloy for a given applied magnetic field (h).
  • This effect has been studied in great detail for new magnetostrictive materials such as iron-gallium (Fe-Ga) alloys, and the data is shown in Figure 5.
  • Fe-Ga iron-gallium
  • Fe-Ga is very similar to Fe-Al, except in the fact that it has a greater magnetostrictive strain. Since the Fe-Al alloys were originally developed in the 1950s and largely ignored since then due to their relatively small magnetostrictive strains, very little is known about the interaction between pre-compressive stresses, bias magnetic fields and magnetic permeability. We do know from the available data that maximum saturation magnetization may be as large as 1.6 Tesla for Fe-Al alloys.
  • methods and devices are included to incorporate magnetostrictive components with the appropriate combination of bias magnetic field and pre-stress that will provide the maximum change in the B -Field in specific magnetostrictive alloys into systems that are designed to generate electric power.
  • methods and devices are included to incorporate magnetostrictive components 108 with the appropriate combination of bias magnetic field and pre-stress that will provide the maximum change in the B -Field in specific magnetostrictive alloys into systems that are designed to generate electric power by harvesting energy from the ocean.
  • magnetic measurements similar to that shown in Figure 5 can help identify the appropriate combination of bias magnetic field and pre-stress which maximize the change in magnetic field as a function of external applied stress.
  • the pre-stress force may be a compressive stress
  • the applied external stress may be a tensile stress.
  • the applied stress is periodic. In one embodiment, the applied stress is caused by changes in tether tension in a system with a tethered buoy 102. In one embodiment, the change in magnetic field is at least 0.1 Tesla, and preferably at least 0.5 Tesla.
  • the next step is to incorporate this into a component design and to develop a manufacturing process that achieve these target values while minimizing component costs.
  • At least one permanent magnet incorporated in the vicinity of the magnetostrictive element or component may be used.
  • the magnet or magnets may be internal to or external to the magnetostrictive component.
  • Embodiments described herein are not specific to the use of permanent magnets, and persons skilled in the art can envision various configurations of permanent magnets or electromagnets to be used for achieving the same or similar bias fields.
  • One embodiment incorporates permanent magnets with the magnetostrictive elements.
  • One embodiment incorporates magnetostrictive components that have one or more bores into which permanent magnets may be incorporated.
  • Magnetic field modeling can be used to design low cost permanent magnet assemblies (based on small rare earth magnets that can achieve the bias fields using, for example, Vizimag 3.18 software.
  • Vizimag software is an electromagnetic modeling simulator software for analysis and simulation of field lines and flux density. The software can be used to analyze fields due to rectangular, toroidal and curved magnets, solenoids and their interaction with user-defined magnetic regions. In some embodiments, a relatively uniform magnetic field of a particular strength is achieved, while reducing or minimizing the number/volume of permanent magnets needed to achieve this field.
  • a process to assemble magnetostrictive cores 110 and/or components 108 into mechanical fixtures can be used to pre-stress the cores 110 or components 108.
  • magnetostrictive components can be used to determine the stress/strain state of the component that is being loaded.
  • load cells can be used to determine the stress/strain state of the component that is being loaded.
  • Magnetic field measurement systems such as Tesla Meters to determine the change in magnetic field under compression to determine both the appropriate strain/load conditions to achieve the desired magnetic domain orientation within the materials may be used in real-time during the manufacturing process.
  • Fig. 6 depicts a schematic diagram of one embodiment of a pre-compression loading system 600.
  • One method of pre-stressing the magnetostrictive components includes putting the magnetostrictive alloy rod (or core 110) under a compressive load condition, in which the core 110 is installed in a fixture 602 that allows applying a compressive load using load application equipment such a hydraulic loading system 600 and the fixture 602 maintains the compressive load on the core 110 once it is removed from the loading system
  • a hydraulic system 600 may include a simple hydraulic cylinder 604 and ram with a manual hand pump and an in-line pressure gauge.
  • the fixture 602 may include two or more flat bars (or structural plates) of metal with holes drilled in them for threaded rods and nuts.
  • the flat bars may or may not be made of a magnetically permeable alloy such as mild steel, or a relatively impermeable alloy such as stainless steel.
  • the use of magnetically permeable flat bars may include additional bars to create a closed flux path.
  • a sample alloy rod is installed in the fixture 602 with one or more flat bar on each end.
  • the compression loading system 600 may include the manual hydraulic cylinder/ram
  • strain gauges may be applied to the sample alloy rod when the process is first set up in order to ensure that the compressive force is maintained on the rod by the fixture 602 once it is removed from the loading system.
  • the method of pre-stressing the magnetostrictive core may include using other mechanical structural components.
  • Fig. 7 depicts a schematic diagram of one embodiment of magnetic domain orientation 700 in a magnetostrictive component 108 under various stresses/magnetic field configurations.
  • the magnetic domains 702 in the poly- crystalline alloy may be randomly oriented and have a net zero magnetic moment.
  • the domains 702 may be oriented to be parallel to the field 704.
  • the magnetic domain orientations can be rotated away from the loading direction so as to be perpendicular to the loading direction.
  • a tensile force 706 is applied, such as by the buoy 102, the load in the magnetostrictive component 108 changes from compressive to zero or slightly tensile resulting in a complete rotation of the magnetic domains 702 and a very high efficiency of energy conversion.
  • the pre-stress and/or bias magnetic fields 704 may be incorporated into the magnetostrictive elements 110/components 108 during processing.
  • the scope of the method or apparatus is not limited by the specific method of incorporation of pre-stress and/or bias magnetic fields 704 (or magnetic domain orientations 702) in the magnetostrictive element 108 during processing. Examples of methods that may be used include, but are not limited to, one or more of the following:
  • Fig. 8 depicts a flow chart diagram of one embodiment of a method 800 for harvesting electrical power from water mechanical, or hydrodynamic, energy. Although the method 800 is described in conjunction with the WEH 100 of Fig. 1, embodiments of the method 800 may be implemented with other types of wave or water mechanical energy harvesters.
  • the method 800 includes tethering 805 a water flotation device 102 to an anchor 106 by a tether 104, wherein the tether 104 includes at least one magnetostrictive component 108.
  • a magnetic property of the magnetostrictive component 108 is configured to change upon an applied force to the magnetostrictive component 108 along a direction within the magnetostrictive component 108.
  • the applied force is a tensile force applied to the magnetostrictive core 110 of the component 108.
  • Other embodiments may apply a compressive force.
  • the WEH 100 uses 810 the movement of the water flotation device 102, or buoyancy force, caused by motion of waves, wave height changes, or otherwise in conjunction with the force from the anchor 106 to create the applied force 706 and changes the magnetic property of the magnetostrictive component 108. Specifically, the applied force 706 changes a magnetic property of the magnetostrictive core 110 of the component 108. Because the applied force 706 changes the magnetic property of the component 108, the WEH 100 is able to create 815 electrical power using the change. In one embodiment, the WEH generates 815 electrical power by inducing a current or voltage in an insulated electrically conductive coil 112 magnetically coupled, wound around, or otherwise coupled to the magnetostrictive core 110 of the component 108. The coil 112 may be in electrical communication with an electrical energy storage device 115.
  • an initial bias magnetic field 704 is applied 820 to the magnetostrictive component 108, such that the initial bias 704 results in some magnetic flux density within the magnetostrictive component 108.
  • the bias 704 may be a magnetic bias created by permanent magnets proximate the core 110.
  • a physical pre-stress force may be applied to the component 108 before connecting the tether to each of the buoy 102 or the anchor 106.
  • the bias magnetic field is directed through the
  • magnetostrictive core through the use of one or more flux paths comprising magnetically permeable material.
  • both a physical pre-stress force and an initial bias magnetic field must be present in the magnetostrictive component 108 in order to generate power.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • General Electrical Machinery Utilizing Piezoelectricity, Electrostriction Or Magnetostriction (AREA)

Abstract

La présente invention a trait à un appareil permettant de collecter de l'énergie électrique provenant de l'énergie hydrodynamique, lequel appareil inclut une plate-forme flottante ou autre dispositif de flottaison sur l'eau qui est relié à une ancre au moyen d'une longe et un composant magnétostrictif qui est doté d'un noyau magnétostrictif précontraint intérieur qui subit au moins une partie des changements de charge subis par la longe. La propriété magnétique du noyau magnétostrictif est configurée de manière à changer avec les changements de contrainte à l'intérieur du noyau magnétostrictif dans au moins une direction à l'intérieur du composant magnétostrictif. L'énergie hydrodynamique agissant sur la plate-forme flottante ou autre dispositif de flottaison sur l'eau a pour résultat des changements de force à l'intérieur de la longe, ce qui à son tour change la contrainte à l'intérieur du noyau magnétostrictif et, par conséquent, change la propriété magnétique. Le composant magnétostrictif est également configuré de manière à ce que le changement de la propriété magnétique ait pour conséquence un changement du flux magnétique, lequel changement peut être utilisé de manière à produire de l'énergie électrique.
PCT/US2011/030977 2010-02-01 2011-04-01 Machine permettant de collecter l'énergie des vagues dotée d'une performance améliorée WO2012024000A1 (fr)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
US30043810P 2010-02-01 2010-02-01
US61/300,438 2010-02-01
US32839610P 2010-04-27 2010-04-27
US61/328,396 2010-04-27
US13/016,828 US8378512B2 (en) 2010-02-01 2011-01-28 Wave energy harvester with improved performance
US13/016,828 2011-01-28

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WO2012024000A1 true WO2012024000A1 (fr) 2012-02-23

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