METHOD FOR GENERATING ELECTRICITY
An electrical generating method is provided that generates electricity when bending of a first flexible plurality of conductors, a second flexible plurality of conductors and a flexible magnetic field source causes movement of the conductors relative to a magnetic field provided by the magnetic field source.
This application relates to commonly assigned, copending U.S. application Ser. No. ______ (Docket No. K000912RRS), filed ______, entitled: “CHANGING RADIUS GENERATOR” which is hereby incorporated by reference.
FIELD OF THE INVENTIONThe present invention relates to energy conversion devices and, more particularly to devices that convert kinetic energy in flows of a fluid into electrical energy.
BACKGROUND OF THE INVENTIONIt has long been a goal of engineers and scientists to develop more effective methods and apparatuses for harvesting the kinetic energy that is present in naturally occurring flows of wind, water or flows of other material. To accomplish this, windmills and turbines have been developed with blades that are joined around a central hub and shaped so that kinetic energy from a fluid flow against the blades urges the blades to rotate about the hub. The velocity and torque with which the hub rotates provides rotational energy that can then be used for other purposes. In some cases, the rotational energy provided at the hub is supplied directly to mechanical systems that perform work such as milling or pumping water. However, most modem windmills and turbines connect electrical generators to the hub to convert rotational mechanical energy into electrical energy.
The blades used in windmills and turbines spin in a direction that is generally normal to a direction of the fluid flow and can have disruptive effects on the fluid flow and on things carried by the fluid flow. The spinning blades are also subject to static and dynamic balance problems. For example, when dynamic unbalance conditions exist, rotation of the blades urges the hub to rotate about an axis other than predetermined rotational axis of the hub. Mountings such as bearings that are used to position the hub for rotation about the predetermined rotational axis provide reaction forces that resist the urging. This reduces the efficiency of the energy conversion process and causes premature bearing failure which increases maintenance costs. These effects in turn increase the cost of electricity produced by windmills and turbines. Additionally, such reaction forces can create noise and vibration in the windmill or turbine that can have a disruptive effect in the area surrounding the windmill or turbine.
What are needed therefore, are methods and apparatuses that allow for the generation of electrical energy in a manner that is less disruptive to the flow of fluid and to the surrounding environment. What is also needed, are methods and apparatuses that generate energy with lower maintenance requirements.
In some cases, efforts have been made to meet these needs through the use of piezoelectric webs. For example, U.S. Pat. No. 6,424,079 issued to Carroll on Jul. 23, 2002 and entitled: “Energy Harvesting Eel” describes a piezoelectric power generator for use in a fluid flowing stream. This piezoelectric power generator has an elongated flexible central layer of a dielectric material with axially along opposite sides thereof a plurality of separate piezoelectric elements each formed from a portion of a continuous layer of the piezoelectric layer extending along each opposite side of the central layer sandwiched between a pair of electrodes unique to each piezoelectric element. In the '079 patent, the piezoelectric power generator is mounted within a water flow and is allowed to undulate in the presence of turbulent forces in the fluid stream. Repetitive flexures of the piezoelectric elements induce stresses in the piezoelectric materials that the piezoelectric materials convert into electrical energy.
In one embodiment of the '079 patent the flow induces a continuous sine wave shape in the elongated structure including spaced crests and troughs. When this occurs piezoelectric layer on one side of the structure is bent into a convex shape and a dielectric layer on the other side is bent into a concave shape. The concave shaped piezoelectric layer is stressed in tension to create an electrical charge for electrodes in contact with it. Conversely the convex concave shaped piezoelectric layer on the opposite side of the structure is stressed in compression to create an electrical charge for electrodes in contact with it.
Other examples where piezoelectric materials are used to generate energy from a fluid flow include U.S. Pat. No. 4,387,318 issued to Kolm et al. on Jun. 7, 1983, entitled: “Piezoelectric Fluid-Electric Generator” which shows a piezoelectric fluid-electric generator including a piezoelectric bending element, means for mounting the one end of the belt the elements in a fluid system, means for driving the piezoelectric element to oscillate with the energy of a fluid stream and electrode means connected to the piezoelectric ending element to conduct current generated by the oscillatory motion of the piezoelectric bending element. In one embodiment of this type, a paddle like blade extends from one end of the piezoelectric bending element to be deflected by the fluid while the other end is rigidly mounted to a support. Yet another example of a piezoelectric generator is shown in U.S. Pat. No. 7,560,856 issued Jul. 14, 2009. In this patent electrical energy is produced by converting kinetic energy from fluid flow with membranes that generate electrical energy in response to deformation by the fluid flow passing through a piezoelectric medium attached to the deforming membranes. Sets of membranes define variable fluid flow restrictors that oscillate due to interaction of the force of fluid flow and Bernoulli effect.
A variety of performance limitations are associated with such piezoelectric systems. One is that the production of electrical energy requires subjecting the piezoelectric materials to cycles of inducing and relieving stresses in the materials. This can lead to early failure of such piezoelectric materials. Further, there are limits as to the extent to which such piezoelectric materials can generate electricity in response to applied energy.
U.S. Pat. Nos. 7,821,144 and 8,026,619 describe another alternative approach to generating energy from a flow of the fluid that requires neither piezoelectric materials nor spinning blades. Instead, in these cases an energy converter is provided that includes a flexible membrane having at least two fixed ends fixed to a frame. The membrane and frame are arranged in a flow of fluid so that the membrane oscillates when subject to fluid flow. One of an electrical conductor and a magnet is joined to membrane and oscillates with the membrane. The other of the electrical conductor and a magnet is positioned proximate to the path of movement of the membrane and apart therefrom. The oscillation of the membrane caused by the fluid flow causes a relative movement between the electrical conductor and the applied magnetic field inducing a current in the electrical conductor.
Although these systems do not have rotating blades, they require that the membrane oscillates across the path of fluid flow, they create noise and they create vibrations. Accordingly, these systems are also disruptive to the flow of fluid, objects in flow of fluid and to the surrounding environment and have efficiency limits due to the loss of energy to noise and vibration and the requirement that they oscillate in the flow of fluid rather than undulate.
Thus, what are still needed in the art are methods and apparatuses that can generate energy from moving flows of fluid such as wind and water and that can do so with greater efficiency, greater reliability and less disruption of the environment.
SUMMARY OF THE INVENTIONMethods for generating electricity are provided. In one embodiment, a flexible magnetic field source between a first flexible plurality of conductors and a second flexible plurality of conductors is placed in a flow of a material, the flexible magnetic field source, the first flexible plurality of conductors and the second flexible plurality of conductors are held at one end along a length while allowing opposite ends of the flexible magnetic field source, the first flexible plurality of conductors and the second flexible plurality of conductors to move relative to each other along the length and the flexible magnetic field source, the first flexible plurality of conductors and the second flexible plurality of conductors are arranged so that forces provided by the fluid to cause the flexible magnetic field source, the first flexible plurality of conductors, and the second flexible plurality of conductors to bend along the length. The bending changes the radiuses of the flexible magnetic field source, the first flexible plurality of conductors and the second flexible plurality of conductors to move the first plurality of conductors and the second plurality of conductors relative to a magnetic field of the flexible magnetic field source that is different at different portions along the length and to induce a currents in the first plurality of conductors and in the second plurality of conductors.
Holder 30 also holds magnetic field layer 40, first layer 60 and second layer 80 such that magnetic field layer 40, first layer 60 and second layer 80 can bend along length 24 in response to an applied force.
As is also shown in the embodiment of
In the embodiment of
In the embodiment of
Given this arrangement an object moving lengthwise along magnetic field layer 40 will experience a range of different magnetic field intensities. When the object is proximate to one of magnetic field sources 48A and 48B, the object will experience greater magnetic field intensity than when the object is more distant from magnetic field sources 48A and 48B.
As is also shown in
In the schematic view of
In the embodiment of
In the embodiment of
As is also shown in this embodiment, conductors 84A and 84B are connected to a first carrier line 86 and to a second carrier line 88. Second carrier line 88 leads to a connection 92A on one side of width 26 at a mounting end 90 of second layer 80 and second carrier line 88 leads to a connection 92B on opposite side of width 26 at mounting end 90 of second layer 80. A connector 106A joins a power harvesting circuit 110 to first carrier line 86 and a connector 106B joins power harvesting circuit 110 to second carrier line 88. In this embodiment, connector 106A and connector 106B also optionally serve to mechanically link second layer 80 to mount 100. In other embodiments, mounting areas 92 can be joined to connector 106A and connector 106B in any other known manner including but not limited to adhesives and fasteners and in that regard a perforation may or may not be used. In an alternative embodiment either or both of connector 106A and connector 108B can be integrally formed from with support 42.
In the embodiment of
In the embodiment of
In the embodiment of
Any or all of magnetic field layer 40, first layer 60 and second layer 80 can have protective or lubricating layers or coating of materials provided thereon to protect supports 42, 62 and 82, conductors 64A, 64B, 84A and 84B and magnetic field sources 48 from environmental, mechanical or thermal damage or to enhance or to otherwise control mechanical properties, electrical properties, or sensitivity to environmental stimuli.
The first flexible array of conductors, the second flexible array of conductors and the flexible magnetic field source are then held at one end along a length but moveable relative to each other at an opposite end such that forces provided by the fluid cause the flexible magnetic field source, the first flexible plurality of conductors, and the second flexible plurality of conductors to bend along the length (step 152). Here too one embodiment this can be done by assembling an electrical generator 20 that has a magnetic field layer 40, first layer 60 and second layer 80 that are held together at mounting ends thereof as is shown in
The flexible magnetic field source, the first plurality of conductors and the second plurality of conductors are arranged in the flow material so that any forces provided by the fluid to cause the flexible magnetic field source, the first flexible plurality of conductors, and the second flexible plurality of conductors to bend along the length (step 154) This can be done for example by orienting the flexible magnetic field source, the first plurality of conductors and the second plurality of conductors in the flow so that forces from the flow tend to vary in ways that will bend the flexible magnetic field source, the first plurality of conductors and the second plurality of conductors along the length. As will be described in greater detail below, this can also be done by providing supports or other structures that cooperate with for example electrical generator 20 to urge bending movement of flexible magnetic field source, the first plurality of conductors and the second plurality of conductors along length 24 shown in
Accordingly, magnetic field layer 40 will have a longer path of travel from mount 100 around bend than second layer 80. This shifts conductor 84A away from magnetic field source 48A by a first vector 142 and also shifts conductor 84B away from magnetic field source 48B by a second vector 146. Similarly, first layer 60 will have a longer path of travel from mount 100 around bend B than magnetic field layer 40. This causes conductor 64A to be separated from magnetic field source 48A by a third vector 140 and causes conductor 64B to be separated from magnetic field source 48B by a fourth vector 144. As is shown in
These displacements cause conductors 64A and 64B and conductors 84A and 84B to move from a position where magnetic field intensity is high as shown in
It will be appreciated that such effects occur in reverse fashion when generator 20 is caused to revert to a non-bent state and/or to reverse a direction of bending and it will be appreciated that when this occurs the flow of current will be reversed.
As was shown in
In the embodiment that is illustrated in
In the embodiment of
Coil 230 provides a first connection point 103 to mount 100 for coil starting at connector 102A and a conductor illustrated here as conductor 236 extends from connector 102A along length 24 and then turns to run parallel to magnetic field source 48A across a width 26 to form conductor 64A. Coil 230 then forms a crossover 234A that crosses over from first layer 60 to second layer 80 and extends across width 26 parallel to magnetic field source 48A to form conductor 84A. Coil 230 then forms loop 232A and returns to first layer 60 to form conductor 64B. This looping arrangement continues in like fashion to form a crossover 234B, followed by a conductor 84B, loop 232B, conductor 64C, crossover 234B, conductor 84C, loop 232C, conductor 64D, crossover 234C, conductor 84D, loop 232D, conductor 64E, crossover 234D and conductor 84E.
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However, in the embodiment of
Support beam 304, in turn, is supported by an airfoil 306 that is pivotally connected to mount 100 by way of a pin 320. In this embodiment, airfoil 306 is self adjusting based upon wind flow. As is also shown in
In the embodiment of
Another wind driven flag type embodiment is illustrated in
This approach increases the flexibility of generator 20 because the device might be integrated into the body of a larger device, thereby not requiring a separate mount. Additionally, power harvesting circuit 110 can be located in such a larger device. In this embodiment 380 and 382 deliver power to load 380A and 382A where these loads could be separate or one and the same.
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It will be appreciated that in any of the above embodiments, a magnetic focusing material such as iron particles can be supplied within the conductor layers surrounding the conductor lines as a magnetic focusing material. In some embodiments of this type, magnetic fields from magnetic field layer 40 can pull first layer 60 and second layer 80 together and act as a holder 30. In such embodiments, separation layer 120 can be used to provide friction reducing materials between the layers.
It will also be appreciated that conductors such as conductors 64A and 64B, and conductors 84A and 84B are shown in schematic form and that the illustrations provided herein are not limiting as to the number, shape, size orientation, or composition of the conductors illustrated herein so long as the conductors are capable of generating current when passed through a changing magnetic field as is described herein or as is known in the art.
The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.
Claims
1. A method comprising:
- placing a flexible magnetic field source between a first flexible plurality of conductors and a second flexible plurality of conductors in a flow of a material;
- holding the flexible magnetic field source, the first flexible plurality of conductors and the second flexible plurality of conductors at one end along a length while allowing opposite ends of the flexible magnetic field source, the first flexible plurality of conductors and the second flexible plurality of conductors to move relative to each other along the length;
- arranging the flexible magnetic field source, the first flexible plurality of conductors and the second flexible plurality of conductors so that forces provided by the fluid to cause the flexible magnetic field source, the first flexible plurality of conductors, and the second flexible plurality of conductors to bend along the length; and
- wherein the bending changes the radiuses of the flexible magnetic field source, the first flexible plurality of conductors and the second flexible plurality of conductors to move the first plurality of conductors and the second plurality of conductors relative to a magnetic field of the flexible magnetic field source that is different at different portions along the length and to induce a currents in the first plurality of conductors and in the second plurality of conductors.
2. The method of claim 1, further comprising the step of supporting the flexible magnetic field source, the first flexible plurality of conductors and the second flexible plurality of conductors at a position along the length that is between the ends that are held and the movable ends to allow a bending node to come into existence between a mounting and a first support point.
3. The method of claim 2, further comprising positioning the first support point to leaving a tail portion between the first support point and an end of the he flexible magnetic field source, the first flexible plurality of conductors and the second flexible plurality of conductors to allow unconstrained bending to provide additional energy generation or to provide mechanical forces that help to induce additional bending of the flexible magnetic field source, the first flexible plurality of conductors and the second flexible plurality of conductors.
4. The method of claim 1, further comprising the step of supporting the holding the flexible magnetic field source, the first flexible plurality of conductors and the second flexible plurality of conductors with a mounting that reacts to the force applied by the flow by urging bending of the flexible magnetic field source, the first flexible plurality of conductors and the second flexible plurality of conductors.
5. The method of claim 1, further comprising using a cover having pockets to hold the flexible magnetic field source, the first flexible plurality of conductors and the second flexible plurality of conductors with a mounting that reacts to the flow by urging bending of the flexible magnetic field source, the first flexible plurality of conductors and the second flexible plurality of conductors.
6. The method of claim 1, wherein at least one of the flexible magnetic field source, the first flexible plurality of conductors and the second flexible plurality of conductors are held by a holder that reacts to the flow at least in part by stretching at least one of the flexible magnetic field source, the first flexible plurality of conductors and the second flexible plurality of conductors.
7. The method of claim 1, wherein the magnetic field layer provides a magnetic field that varies in intensity along a length of the magnetic field layer to provide variations in field intensity that are generally parallel to said conductors.
8. The method of claim 1, further comprising rotating poles of one or more magnetic fields during the bending.
9. The method of claim 1, further comprising dampening the magnetic fields between the magnetic field sources and the first flexible plurality of conductors.
10. The method of claim 1, further comprising dampening the magnetic fields between the magnetic field sources and the second flexible plurality of conductors.
11. The method of claim 1, further comprising positioning magnetically conductive material between poles of the same polarity.
12. The method of claim 1, further comprising the steps of alternately dampening and conducting the magnetic field from the magnetic field source.
13. The method of claim 1 wherein during a first direction of the bending, the first plurality of conductors has an outer bending radius that is greater than a middle bending radius of the magnetic field source and the second plurality of conductors bends at an inner radius that is less than the middle radius and wherein the first plurality of conductors move in a first direction relative to the magnetic field to induce a first current in the first flexible plurality of conductors and the second flexible plurality of conductors move in a second direction relative to the magnetic field to induce a second current in the second plurality of conductors that is opposite to the first current.
14. The method of claim 1, wherein the first plurality of conductors and second plurality of conductors comprise respectively a first portions of a coil that extend across the width of the magnetic field layer proximate to a first side of the magnetic field layer and second portions of the coil that extend across the width of the magnetic field layer proximate to a second side of the magnetic field layer.
15. The method of claim 1, wherein the arrangement of the first flexible plurality of conductors, the second flexible plurality of conductors, and the variable magnetic field are selected so that the electrical generator bends only in one direction along the length of the generator apparatus in response to an application of kinetic energy at any given time and oscillates between a first direction of bending and a second direction of bending as an amount of applied kinetic energy increases.
16. The method of claim 1, wherein the placing of the flexible magnetic field source between the first flexible plurality of conductors and the second flexible plurality of conductors in a flow of a material includes placing a friction reducing material between the flexible magnetic field source and at least one of the first flexible plurality of conductors and a second flexible plurality of conductors.
17. The method of claim 1, wherein the placing of the flexible magnetic field source between the first flexible plurality of conductors and the second flexible plurality of conductors in a flow of a material includes placing a separation material between the magnetic field source and at least one of the first flexible plurality of conductors and the second flexible plurality of conductors.
18. The method of claim 1, wherein one of the flexible magnetic field source, the flexible first plurality of conductors, and the flexible second plurality of conductors has wrapping portions that extend beyond the widths of the other ones of the first layer, second layer and third layer to form holding surfaces within which the other ones of the first layer, second layer and third layer can bend and within which a separating material is placed to reduce friction between the moving layers and the wrapping portions.
19. The method of claim 1, wherein the flexible magnetic field source, the flexible first plurality of conductors, and the flexible second plurality of conductors are arranged within a buffed body that is shaped to urge the bending.
Type: Application
Filed: Aug 30, 2012
Publication Date: Mar 6, 2014
Inventor: David N. Dupra (Rochester, NY)
Application Number: 13/599,224
International Classification: F03B 13/10 (20060101);