GENERATOR AND CIRCUIT UTILIZING FLUID-INDUCED OSCILLATIONS

CROSS-REFERENCE

[0001] This application claims the benefit of priority to U.S. Provisional Application No. 60/950,227, filed July 17, 2007, which application is incorporated herein by reference.

FIELD OF DISCLOSURE

[0002] This application generally relates to harvesting energy from flowing fluids, and more specifically, to a unique design of an energy converter and generator that induce oscillations by flowing fluids and utilize the oscillations to produce electricity. Specific illustrative magnetic field generating means, electrically conductive coil embodiments and related circuits are described.

BACKGROUND OF THE INVENTION

[0003] A generator may produce AC output, which may be converted and boosted to useful DC outputs for most applications, hi some situations, the generator may produce low voltage AC output. Low voltage operations may include operations below 12 volts DC. Low voltage operations may have applications, such as operating a small portable radio, a wireless sensor node, a bright LED, a super capacitor, a Lithium Polymer battery, or small NiMh batteries. [0004] Previous means of converting low AC power input in generators include using a typical bridge rectifier, and then a separate boost/buck converter to increase the voltage. In situations where there may be a dynamic range in the generator means (such as those caused by varying fluid velocities for a fluid-driven generator), a circuit may be operating at AC input voltages that a standard bridge rectification technique may not be as efficient at converting, or that a boost/buck converter or transformer would not be efficient at raising to voltages that are useful in most applications. Additionally, a boost/buck converter may include a silicon component, and maybe complex and expensive. [0005] Previous systems may also have used an inductive transformer combined with a bridge rectifier. However, such an implementation results in significant power loss in the transformer windings and core, and the bulk and costs of such transformers could be prohibitive for small scale operations. Previous systems may have attempted to eliminate the transformer, but that could also result in a penalty in efficiency. [0006] Some of these previous attempts may have been related to multiplier circuits designed to boost an AC input voltage to 100+ volts, in applications such as electron guns in television sets and ionizers. Multiplier circuits of any sort are not known to have been associated with lower voltage, such as 1 to 12 VDC, applications. It may be advantageous, however, to develop

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a variation of a multiplier circuit that is designed to operate applications within this lower voltage range, particularly when combined with a low-cost, low voltage AC generator. Moreover, a new use for a multiplier circuit that may include voltage rectification, load isolation, and resonance matching, along with low voltage boosting, may increase the efficiency of the power conditioning process.

[0007] Therefore, a need exists for a device that can provide efficient power generation and power delivery to a load. A further need exists for efficient current conditioning of low AC supplies while minimizing complexity and cost, and that may operate for small scale implementations .

SUMMARY OF THE INVENTION

[0008] This disclosure describes various embodiments of unique generators and circuits that effectively promote oscillations induced by flowing fluids, and utilize the oscillations in generating electricity or other types of energy. In one aspect, an exemplary generator harnesses the energy of fluid flows by way of aeroelastic flutter (e.g., "flutter") induced along a tensioned membrane, or "belt", fixed at two or more points. Attentions are drawn to U.S. Patent Application No. 11/566,127, entitled "GENERATOR UTILIZING FLUID-INDUCED OSCILLATIONS," the entire disclosure of which is incorporated herein by reference. [0009] An exemplary electrical generator may include at least one magnetic field generator, at least one electrical conductor, and at least one flexible membrane having at least two fixed ends. The membrane may vibrate when subject to a fluid flow. One of the electrical conductor and the magnetic field generator may be attached to the membrane and configured to move with the membrane. The vibration of the membrane caused by the fluid flow may cause a relative movement between the electrical conductor and the applied magnetic field. The relative movement may cause a change in the strength of the magnetic field applied to the electrical conductor, and the change in the strength of the magnetic field applied to the electrical conductor may induce a current flowing in the conductor. In one aspect, the direction of the magnetic field may be substantially perpendicular to an area enclosed by one or more electrical conductors, when the membrane does not vibrate. [0010] In one embodiment, the exemplary generator may further include a supporting structure. The fixed ends of the membrane may be affixed to the supporting structure. One or more magnetic field generators can be attached to one or more surfaces of the membrane. One or more electrical conductors may be disposed on the supporting structure. In another embodiment, the magnetic field generators may be oriented so as to project the magnetic fields perpendicular to the plane of the membrane. In still another embodiment, by virtue of the

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geometries of the magnetic field generators, the magnetic fields may project into various planes, relative to the membrane-plane.

[0011] The electrical conductors may be rearranged in each corresponding embodiment to account for changes in the magnetic field orientation. In some embodiments, a plurality of electrical conductor coils may be arranged to capture maximum magnetic flux change in various planes. In yet other embodiments, the toroidal shape of the electrical conductor coils may be altered to better utilize the changing flux of the oscillating magnetic field generators. Examples of conditioning circuits for use with the generators may also be described. [0012] The generator may produce AC output, which may have a dynamic range, depending on the generator means. The generator may produce low voltage AC, which may be converted and boosted to useful DC outputs for most applications. The generator means may also be isolated from the loads, since a moving generator means may not have enough momentum to overcome sudden loading conditions. [0013] A power conditioning circuit may combine five simultaneous modes of operation and may include AC to DC conversion and powering directly from an AC power source without a transformer. The circuit may supply (1) rectification, (2) voltage boosting, (3) load isolation, (4) resonance matching, and (5) power storage which may have not been used previously in this circuit configuration at low input AC voltages. The modes may act synergistically in conditioning the electrical output of a generator. Multiple power conditioning circuits may be combined for use in series or parallel to allow for adaptive power using multiple generator means in tandem with low loss.

[0014] Additional aspects and advantages of the present disclosure will become readily apparent to those skilled in this art from the following detailed description, wherein only exemplary embodiments of the present disclosure are shown and described, simply by way of illustration of the best mode contemplated for carrying out the present disclosure. As will be realized, the present disclosure is capable of other and different embodiments, and its several details are capable of modifications in various obvious respects, all without departing from the disclosure. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive.

INCORPORATION BY REFERENCE

[0015] All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings of which:

[0017] FIG. Ia is a perspective view of an exemplary generator according to this disclosure.

[0018] FIG. Ib is a side view of this same exemplary generator.

[0019] FIG. Ic is a side view of this same generator with an example of airflow direction and membrane oscillation profile indicated.

[0020] FIG. 2 is a side view of a variation of the coil and mounting structure of a generator embodiment.

[0021] FIG. 3 a is a circuit diagram of a power conditioning circuit designed for a single generator. [0022] FIG. 3b is a circuit diagram of a power conditioning circuit designed for a dual generator.

DETAILED DESCRIPTION OF THE INVENTION

[0023] In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. It will be apparent, however, to one skilled in the art that the present disclosure may be practiced without these specific details. In other instances, previously taught structures and devices are shown in block diagram form in order to avoid unnecessarily obscuring additional embodiments. [0024] An exemplary electrical generator may include a magnetic field generator, an electrical conductor, and a flexible membrane for converting energy present in fluid flows, such as air flows, water flows, tides, etc., into vibrations or oscillations. In the exemplary embodiments described herein, the flexible membrane may include at least one magnetic generator attached thereto and may have at least two fixed ends. The membrane may vibrate when subject to a fluid flow. As used herein, the term "flexible" may refer to a membrane that has the ability to morph into a large variety of determinate and indeterminate shapes without permanent damage in response to the action of an applied force.

[0025] The at least one magnetic field generator may be implemented as permanent magnets attached to the membrane and configured to move with the membrane. For instance, one or more said magnets may be integrated into or onto either side of the oscillating membrane. Those

magnetic field generators may be suspended over corresponding electrical conductors. The electrical conductors may be implemented as aluminum or copper coils of various geometries. [0026] The vibration of the membrane caused by the fluid flow may cause a relative movement between the electrical conductor and the applied magnetic field of the permanent magnet. The relative movement may cause a change in the strength of the magnetic field applied to the electrical conductor, and the change in the strength of the magnetic field applied to the electrical conductor may induce a current flowing in the conductor. [0027] When using wind or air flow to drive the exemplary generator, wind may flow perpendicularly to a long axis of the membrane, such as when a membrane has an elongated shape. The flowing fluid may induce a spontaneous instability in the tensioned membrane known as aeroelastic flutter, or simply "flutter". The flutter of the membrane may, in some cases, result in a variety of high energy oscillations. In some instances, the unstable flutter oscillations may achieve a limit cycle that may provide stable oscillation modes of the membrane. Additionally, vortices shedding may occur along the edges and surface of the membrane, in some cases enhancing the oscillation.

[0028] The vibration of the membrane thereby may cause the magnets to move relative to the coils. A changing magnetic field can cut through the closed area defined by the coils, thus resulting in an EMF within said coils. Thereby an electrical flow may result, without requiring the physical coupling of the vibrating membrane to a piston or cam system for power generation. This electric generator may operate at a variety of wind speeds, including in some cases lower speeds than required for most turbine-based wind generators. Moreover, the cost of an exemplary generator of this disclosure may be substantially lower than most other wind-based generators, and the absence of physically grinding parts may offer the possibility of long, quiet, maintenance-free operation. No leading bluff bodies may be required to initiate or sustain oscillation, although they can be employed if desired.

[0029] In the embodiments described herein, two permanent magnets may be affixed to the surfaces of the membrane near a single end of the membrane. As described in the specific variations taught herein, the magnets may be compelled into a slight arched, approximately torsion-less (relative to the major axis of the membrane) oscillation via the flutter effect of the membrane. Two corresponding electrical conducting coils may be affixed to approximately stationary supporting structures and/or clamps at various orientations relative to the permanent magnets. More or less magnets and conducting coils may be employed to achieve desired cost and power efficiencies. [0030] FIG. Ia depicts an exemplary generator 100 according to this disclosure. The generator 100 may include a supporting structure 10, two supporting structure clamps 12 and 14,

and two electrical conducting coils 2a, 2b attached to said structure 10 and clamp 12. Generator 100 may also include an elongated membrane 8 with two permanent magnets 4a, 4b affixed to both surfaces of said membrane 8. Membrane anchors sets 6a, 6b may be attached near both ends of said membrane 8 at a specific separating distance. The coils 2a, 2b may be adhered to the surface of or within the supporting structure 10 and the clamp 12, and suspended over the magnets 4a, 4b, respectively. Two leads 18a, 18b may be coupled to coil 2a and two leads 18c, 18d are coupled to coil 2b. The tension applied to the membrane 8 may be a function of the elasticity of said membrane and the physical characteristics of the supporting structure 10, along with the particular distance between the ends of the supporting structure relative to the distance between the anchor sets 6a and 6b.

[0031] The exemplary generator 100 shown in FIG. 1 may operate as follows. A flow of fluid, which may include flows of water for instance, or a flow of air such as that found in artificial ventilation systems or in natural wind, may travel across the elongated and tensioned membrane 8. This fluid flow may travel in a direction ranging from 0 to 180 degrees relative to the major axis of the membrane, with perpendicular flow (e.g. 90 degree to the major membrane axis) giving approximately the most energetic oscillation. Fluid may flow from either side of the generator 100. One example of this fluid flow may be indicated by three arrows in FIG. 1. [0032] The fluid flow may initiate a self-exciting instability (e.g., flutter) in the membrane 8 which may be enhanced through a positive feedback loop of competing fluid deflection and membrane tension forces, until an approximately constant oscillation state is achieved. The majority of the membrane 8 (e g.. the middle section) may undergo a combination of moderate torsional (e.g., slight back-and-forth rotation along the major axis of the membrane 8) and "rising and falling" travel (the profile of the "rising and falling" travel of the membrane 8 is depicted in FIG. Ic), which is quickly recognizable as a "flutter" oscillation. That said, in its most energetic mode the generator 100 may translate this moderate torsional and "rising and falling" movement of the mid-section of the membrane 8 into a reduced torsion oscillation at the location of the magnets 4a, 4b on the membrane 8. It should be noted that a more highly torsional, less linear oscillation of the magnets 4a, 4b may be achievable with nearly the same construction of generator 100, requiring only a slight alteration to the tensioning of the membrane 8 and placement of the magnets 4a, 4b. However, the most energetic oscillation of the magnets, and consequently the oscillation with the most capacity for electrical output, may be the oscillation whereby the magnets 4a, 4b and the end of the membrane 8 on which the magnets may be placed move in a largely torsion-free, slightly arched path. This oscillation mode may be depicted in FIG. Ib, with small arrows indicating the movement of the magnets 4a, 4b on the membrane 8.

[0033] This oscillation of the magnets 4a, 4b may create a changing magnetic field through the closed area of the coils 2a, 2b, with the magnetic fields oriented such that an electromotive force (EMF) may be established in the conductive material of the coils 4a, 4b. The EMF may create a current, i.e., a flow of electrons, dependent on the load conditions, internal resistance, impedance, and a range of other factors. As applies to electrical generators of any sort, this fundamental arrangement of a changing magnetic field relative to a coil of electrical conductive material may follow the physical rules originally described by Michael Faraday. However, the generator 100 may have the significant advantage over conventional generators that no physically grinding parts may be required to generate an electrical flow. [0034] In the illustrative mode of oscillation, the magnets 4a, 4b may oscillate approximately in phase with each other. The electricity flowing through respective leads 18a-d may therefore be combined without significant destructive interference. The leads 18a-d may be joined in parallel or series, depending on the desired voltages and currents fed into a power conditioning circuit associated with the generator 100. [0035] The configuration shown in FIG. Ia, and further clarified in FIG. Ib, may be designed to move a substantial mass (e.g., the magnets) at high frequency, with some displacement. At its most fundamental level, the generator 100 can be modeled as a simple machine that may achieve a mechanical advantage in a manner akin to the way in which a lever converts a large translated motion with little force into a smaller motion with a greater potential force. This greater force nearer the ends of the membrane may be what allows for the high frequency oscillation of the substantial mass of the magnets 4a, 4b, even in low speed fluid flows. By achieving higher frequency oscillation than would otherwise be possible, less magnetic field generating material (e.g., smaller magnets) may be required to achieve efficient conversion of the kinetic energy of the fluid flow into electricity. This may translate into less expensive generators. Additionally, by placing the magnets 4a, 4b largely out of the path of the flowing fluid, the majority of the mid-section of the membrane can respond to those flows without impediment.

[0036] Referring now to the particular construction of the supporting structure 10 and clamps 12, 14, FIG. Ia and FIG. 2a show that the membrane may be captured in between the clamps 12, 14 and the supporting structure 10. The clamps 12 and 14 may be fixed to the supporting structure 10 by any number of means, such as by adhesive or mechanical fasteners such as bolts with nuts or screws, as well as via many other well-understood options. For clarity, screws 16a- d may be used in the pictured generator 100, which may be fed into tapped holes in the supporting structure 10. A thread-less through-hole extending the entire thickness of the structure 10 could be employed instead, and corresponding bolts and nuts could be applied.

[0037] The anchor sets 6a, 6b may be affixed to the membrane 8, again through any number of means. In the case of the generator 100, the anchor sets 6a, 6b may be adhered to the membrane 8 with adhesive. These anchor sets 6a, 6b may be separated by a pre-defined distance, and it is this distance relative to the overall length of the supporting structure 10 that may establish a particular tension of the membrane 8.

[0038] FIG. 2 may depict a sectional side view of a slight variation of the generator 100 described in FIG. Ia. A supporting clamp 13 and a supporting structure 11 may be angled slightly, so as to more efficiently capture the slight arched travel path of the magnets 4a, 4b. This same effect may be achieved by shimming a side of each of the coils in the generator depicted in FIG. Ia.

[0039] In some situations, a generator may produce low voltage AC output, which may vary depending on a moving component of the generator (such as a fluid-driven oscillating membrane). For example, a single device of the sort described in FIG. Ia operating at a wind speed of 5.5 m/s may produce 30 milliwatts of power. Under matched load conditions, this may come out to 1.5 volts root mean square (RMS) at 20 milliamps RMS. This device may also operate at lower wind speeds, and the output of the generator can be as low as 0.6 volts RMS in 2.5 m/s wind speeds, in some examples.

[0040] The power produced by a generator may be conditioned by a power conditioning circuit. For instance, the AC outputs produced by a generator unit may be converted and boosted to useful DC outputs for most applications. The generator may also be isolated from the loads, since a moving part of a generator unit may not have enough momentum to overcome sudden loading conditions.

[0041] Regarding conditioning of the power produced by the generators disclosed herein, a power conditioning circuit of the sort shown in FIG. 3 a may be particularly efficient at converting the output of the generators into clean DC. The circuit may include a plurality of diodes, such as low-leakage Schottky diodes, and a plurality of capacitors, such as low ESR tantalum or electrolytic capacitors. Many different types of diodes and capacitors can be used and the functionality of the circuit may remain approximately the same, hi one embodiment, the circuit may include two diodes and two capacitors. Other numbers of diodes and capacitors, such as three diodes and three capacitors, or four diodes and for capacitors, for instance, can also be used to achieve different power conditioning characteristics, such as output voltage and impedance matching. The "coils" indicated in the circuit diagram may represent a two-coil windbelt generator input. An output voltage to a load may also be connected to the circuit as shown.

[0042] When used in conjunction with the generators described herein, the circuit illustrated in FIG. 3a may accomplish voltage rectification, voltage boosting, load isolation, resonance matching, and power storage, and may thereby increase the efficiency of the power conditioning process. The power conditioning circuit may combine four simultaneous modes of operation and may include AC to DC conversion and powering directly from an AC power source without a transformer.

[00431 The power conditioning circuit may supply rectification to an AC voltage derived from a generator unit. One embodiment of the circuit may provide two rectifiers achieving rectification on alternate AC waveform cycles. The first half- wave of an AC input may be directed by one of the diodes to a capacitor. The capacitor may be charged based on the peak of the AC input waveform. On the second half an AC input (i.e. during the negative phase), a second diode may direct the flow to a second capacitor, which may be charged based on the peak of the second half of the wave form. The capacitors may have a combined or additive DC output to a source with a lower voltage (i.e. a battery or a super capacitor), which may allow efficient AC to DC conversion to take place by the same pathway that may allow voltage boosting.

[0044] Voltage boosting may involve increasing an AC voltage to a higher DC voltage. A diode and capacitor combination may convert the peak of an AC voltage signal into a DC signal, and may thereby boost the voltage. In one embodiment, the combination may boost an AC RMS voltage of 2 volts to 5.6 volts DC. [0045] The power conditioning circuit may also perform load isolation, which may reduce stalling typically caused by a sudden large load being connected to the generator windings (as a result of a sudden increase in the opposing magnetic field produced by current flowing in the generator windings). The efficiency of power delivered from a generator (such as an oscillating membrane generator of the sort described in this disclosure) to a load may be dependent on load conditions. A matched load to a power source may act as a load impedance that may be matched to the impedance of the internal power source. Loads that are low in relative impedance may tend to reduce the efficiency of an inductive AC source. Under extreme load conditions, such as charging a supercapacitor, currents flowing through the windings of said AC source may further reduce power converter efficiency. [0046] Load isolation may be a physical means of disconnecting direct DC connection between a load and a source. Conventional bridge and half bridge rectification techniques may use diodes. However, diodes alone may not provide full load isolation and a DC path may still be intact in those circuits. However, the power conditioning circuit described herein provides a system where the back EMF DC path may be more blocked by the implementation of capacitors in place of some of the diodes in the conventional bridge rectifier.

[0047] The power conditioning circuit may provide a means for providing load isolation while not requiring an inductive transformer and all of the loss of efficiency, and the bulk and costs that are associated with it. By selecting capacitors with a reactance better matched to the operating frequency of a generator's frequency, the inductive transformer may not be necessary. The capacitors may be selected based on the inductive reactance of the coil and operating frequency of the generator means, and may allow efficient passage of AC into DC through the circuitry by preventing substantial amounts of converted DC current back into the circuit as back

EMF.

[0048] The power conditioning circuit may provide resonance matching. A generator may convert mechanical energy into electrical energy with the use of one or more changing magnetic fields and one or more conducting coils. A coil may function as an inductor with an inductive reactance proportional to the operating frequency of the mechanical component of the generator (such as a membrane). As the size of the coil increases, the reactance (opposition) to current flow may increase for a given generator's frequency of operation. Losses in efficiency may occur if the generated current lags the generator AC voltage. Current in an AC system may tend to lead voltage, so the combination of a generator inductance and proper selection of power conditioning circuit capacitance may be tuned to be resonant with the frequency of the moving part of a generator (i.e. membrane). At resonance, the capacitive reactance and inductive reactance may cancel one another out, and more power may be delivered to the load. [0049] The power conditioning circuit may further provide a means for power storage.

Utilizing a supercapacitor in the power conditioning circuit enables the functionality of storing large amounts of electrical energy at the DC voltage. This is particularly useful for applications where a low-power generator is required to supply a load that requires more power that can be provided continuously. In this application, the power conditioning unit can be used to charge an appropriately sized capacitor, with said capacitor either being separate or a component of the power conditioning circuit, until the required energy is achieved. [0050] In contrast to the multiple modes of operation that may be accomplished simultaneously with the power conditioning circuit provided, low power AC generators can only achieve rectification and voltage boosting in several separate operations. For instance, they may typically require a bridge rectifier and a separate boost/buck converter to increase the voltage. In other words, most low- voltage AC generators require a rectifier in addition to a much more expensive silicon device to accomplish what the circuit in FIG. 3a can do more simply. Cost may also be a significant advantage of the circuit described in FIG. 3a; in mass quantity, its cost may be estimated at around $0.25, versus 10 to 20 times more cost for the traditional power conditioning combination of buck/boost converters and rectifiers. The power conditioning

circuit has been designed specifically to address the needs of the wind generators described in this application; however, it also may be applied towards cheaply and efficiently conditioning power produced by other low voltage, low power generators (e.g. vibrational generators, linear generators). [0051] Also of note, the electrical output of multiple generators can be combined and conditioned with a variation of the aforementioned circuit. FIG. 3b illustrates a circuit capable of combining the outputs of two generators. Dual power conditioning circuits can be switched to operate either together or separately in accordance with another embodiment of the invention. By having dual power conditioning circuits, the invention may provide for the operation of more than one generator means for a generator. The outputs can then be selectively combined to yield higher voltages or currents, such as with a switch as noted in FIG. 3b, depending on the application to be powered.

[0052] Multiple power conditioning circuits can be switched to operate in series or parallel, or separately. For instance, two power conditioning circuits, such as the one illustrated in FIG. 3a, may be arranged so that they may be connected by a switching arrangement, such as a four pole three position switch, as shown in FIG. 3b. The switching arrangement may have three positions allowing separate operation, parallel operation, and series operation. The switching arrangement may allow separation operation if the switches are not connected to the wires shown (in neither "up" nor "down" position). The switches may allow series operation if they are in "up" position and connected to the wires. The switches may allow parallel operation if they are in "down" position.

[0053] Dual power conditioning circuit switching may allow the two generator means to be combined as described with the same efficiency as described for a single operation. This switching mechanism may be applied for additional power conditioning circuits, so that any number of power conditioning circuits may be connected to allow their respective generators to operate separately, or in series or in parallel.

[0054] The power conditioning circuits provided may be used for multiple generators with differing characteristics. An appropriate capacitive component may be selected based upon the resonant frequency of a moving part of a generator (i.e. membrane) and the inductive reactance of the generator coil. However, a given circuit may be tuned to various generator scales (with different characteristic frequencies) with the application of two inductors that may be spaced a certain distance from one another, or through the application of conventional radio tuning coils with ferrite coils. [0055] Some additional variations worthy of mention involve the tensioning of the membrane 8. In certain arrangements, the leading and trailing edges of the membrane could be

tensioned to varying degrees, to encourage oscillation at lower wind speeds. In these instances, the generator may no longer be able to convert fluid flowing from both sides of the generator. Similarly, in some instances the magnets may not be mounted directly on the centerline of the membrane, but rather may be mounted closer to one edge of the membrane, such as the leading or trailing edge. This can encourage a self-starting oscillation and also may yield a more energetic oscillation, for certain configurations. Moreover, the membrane can be variably tensioned, depending on the wind speed at a particular moment, to yield higher frequencies of oscillation at higher wind speeds, without significantly larger displacement of the membrane. [0056] Another feature that can help to compel the membrane 8 into oscillation at the low threshold of wind speed for a particular generator may involve a supercapacitor. The supercapacitor, which may be charged by external means or by the generator itself, may discharge pulses of current into the coils of the generator. These pulses of current forced through the coils may create a magnetic field that either opposes or attracts the membrane-mounted magnets; this force of repulsion or attraction has been shown to reliably compel the membrane into oscillation at low wind speeds that would otherwise not excite the membrane into regular oscillation. The discharge of the supercapacitor into the coils can be controlled by any number of timer circuits, or by circuits that are triggered by external wired or wireless means. Also, the discharge may be triggered by the low-voltage signal produced by the generator itself as the membrane quivers just below the low-threshold of excitation. [0057] While a great many variations of the generators described herein are possible, the particular dimensions of the membrane 8 and the placement and geometry of the magnets 4a, 4b may be important to the construction of an efficient generator. It has been determined empirically that a length-to-width ratio of the membrane 8 of approximately ranging from 2:1 to 1000:1 may be important in establishing a highly energetic flutter oscillation, although this ratio is highly dependent on the physical characteristics of the membrane and other components of the generator. For instance, the length-to- width ratio of the membrane 8 may also be ranging from 30:1 to 1000:1, or from 35:1 to 100:1. The magnets can be of various shapes, such as disk- shaped or rectangular, with various magnetic field orientations. [0058] It should be understood from the foregoing that, while particular implementations have been illustrated and described, various modifications can be made thereto and are contemplated herein. It is also not intended that the invention be limited by the specific examples provided within the specification. While the invention has been described with reference to the aforementioned specification, the descriptions and illustrations of the preferable embodiments herein are not meant to be construed in a limiting sense. Furthermore, it shall be understood that all aspects of the invention are not limited to the specific depictions,

configurations or relative proportions set forth herein which depend upon a variety of conditions and variables. Various modifications in form and detail of the embodiments of the invention will be apparent to a person skilled in the art. It is therefore contemplated that the invention shall also cover any such modifications, variations and equivalents.