WO2011046383A2

WO2011046383A2 - Wind-powered electricity generating device and a dual wind-powered electricity generating system

Info

Publication number: WO2011046383A2
Application number: PCT/KR2010/007075
Authority: WO
Inventors: 박정열; 장형관; 김대중; 윤길호
Original assignee: 서강대학교 산학협력단
Priority date: 2009-10-15
Filing date: 2010-10-15
Publication date: 2011-04-21
Also published as: WO2011046383A3

Abstract

The wind-powered electricity generating device uses the wind to generate electrical power, and comprises: a pressure-changing means which is disposed in the path of movement of the wind and creates changes in pressure over time; and a piezoelectric element which is disposed adjacent to the pressure-changing means and generates electrical power due to the changes in pressure over time.

Description

Wind Turbine and Dual Wind Power System

The present invention relates to a wind power generator for producing electricity by using wind, and more particularly, a power generation module and other kinds of power generation that can generate power by itself according to a non-contact method and can be harmonized with other power generation modules. A dual wind power generation system in which modules are harmonized.

Recently, as the development of semiconductor technology enables the development of low power semiconductor devices and modules, there is increasing interest in the commercialization of a ubiquitous sensor network (USN). As the size and price of sensor nodes used in USNs decrease and the possibility of commercialization increases, efficient energy supply becomes a problem. However, because miniaturization of CMOS electronic circuits is ahead of battery-intensive technologies, it is not easy to use batteries due to size constraints or economic burden. Therefore, in recent years, research is being actively conducted on a method of easily supplying electric energy using solar heat, vibration, heat, wind power, wave power, etc., which can be easily obtained in daily life.

An example of research to harvest energy from natural energy is to use piezoelectric elements to easily convert mechanical energy into electrical energy. Using piezoelectric elements requires three steps to harvest energy. (a) It must be possible to create and transfer periodic stresses from the available natural energy sources to the piezoelectric element. (b) The mechanical energy is to be converted into electrical energy using the piezoelectric effect. (c) be capable of processing and storing electrical energy. However, the natural energy available in daily life is difficult to control and use its power. The harvesting of energy using piezoelectric elements requires periodic stresses, but the wind has a constant velocity of velocity without significant change, making it difficult to use the force. As an example of the existing research for controlling wind, a method of converting wind into rotational force of a propeller shaft and harvesting energy by applying a force to a piezoelectric cantilever directly by a stopper on the shaft is proposed. However, because the stopper must directly stress the piezoelectric cantilever, initial stress is required, making it difficult to operate at low wind speeds and additional costs due to damage problems of the piezoelectric cantilever.

The present invention produces electricity from the piezoelectric element using the changes caused from the wind and the surrounding environment, while producing electricity without applying stress to the piezoelectric element in direct contact with a specific object, thereby preventing damage to the piezoelectric element, It does not require an initial stress value to move a specific object, providing a wind turbine that can produce electricity at low wind speeds.

The present invention provides a wind power generator having an optimal shape so that the piezoelectric element of the cantilever type to produce electricity by using the wind to produce high-efficiency electricity.

The present invention provides a dual wind power generation system that can maximize the production efficiency by producing auxiliary electricity using a propeller in addition to the piezoelectric element of the cantilever type.

According to an exemplary embodiment of the present invention, a wind turbine generating power using wind is disposed adjacent to the pressure change means and the pressure change means arranged on the movement path of the wind to generate a pressure change over time. It is disposed includes a piezoelectric element portion for generating power by the pressure change over time.

The piezoelectric element portion is a structure capable of generating electric power by using piezoelectricity, in which electrical polarization occurs when a piezoelectric element is subjected to mechanical pressure such as strain, and has a single layer or a multilayer structure. It may be provided, and materials of various shapes and structures may be selected.

The piezoelectric phenomenon and the wind of the piezoelectric element is used. Conventionally, the stopper is rotated by wind, and the stopper repeatedly hits the piezoelectric element repeatedly, thereby generating electric power by applying a periodic stress to the piezoelectric element. There is. This method requires a minimum initial stress that pushes the stopper in contact with the piezoelectric element, making it difficult to operate at low wind speeds, and the more damaged the piezoelectric element is due to the friction between the stopper and the piezoelectric element.

However, in the wind power generator according to the present invention, instead of applying a stress to the piezoelectric element by touching the piezoelectric element with a specific object, the wind power itself is used to apply power from the piezoelectric element by applying stress to the piezoelectric element. Produced, no initial stress is required, and the piezoelectric element is not damaged at all.

However, in order for the piezoelectric element to continuously generate power, the piezoelectric element must be repeatedly stressed.

Thus, in the present invention, the wind is used, but generally includes a pressure change means for allowing the wind having a constant velocity without a large change to have a pressure change over time.

The pressure changing means is disposed adjacent to the piezoelectric element portion in front of the piezoelectric element portion, so that the wind has a pressure change with time in the vicinity of the piezoelectric element portion disposed on the wind path, thereby causing vibration of the piezoelectric element portion.

At this time, the pressure change means is disposed in front of the piezoelectric element portion is effective to induce vibration of the piezoelectric element portion, and the pressure change means according to the rotating body having a plurality of wings, the object fluttering in the wind, the wind direction It can be a variety of physical structures, such as swinging objects.

In addition, when the frequency of the wind whose pressure changes with time by the pressure changing means coincides with the natural frequency of the piezoelectric element portion, it is possible to produce the maximum power.

In addition, in the case of using the propeller as the pressure change means, the propeller may be equipped with a rotating shaft rotating together with the propeller, and an auxiliary power generation unit including a stator disposed along the periphery of the rotating shaft. The auxiliary power generation unit can generate general power using a rotor and a coil, and since the power generation module using the piezoelectric element does not make physical contact with the auxiliary power generation unit, the power generation efficiency by the existing auxiliary power generation unit can be further increased.

In the wind power generator of the present invention, by using a pressure change means for allowing the wind provided by the piezoelectric element to periodically change the pressure, the piezoelectric element may be periodically vibrated by the wind to produce power.

Since the wind power generator of the present invention is not a method of transferring a stress to the piezoelectric element by directly contacting a specific object with the piezoelectric element as in the prior art, breakage of the piezoelectric element does not occur and initial stress for moving a specific object. No value is required so electricity can be produced at low wind speeds.

The wind power generator of the present invention can increase the efficiency of electricity production by changing the shape of the cantilever-shaped piezoelectric element in accordance with the characteristics of the periodic wind.

In addition to the wind power generator auxiliary generator of the present invention, it is possible to increase the efficiency of electricity production using a propeller in addition to the piezoelectric element.

1 is a perspective view illustrating a wind power generator according to an embodiment of the present invention.

2 is a cross-sectional view taken around the piezoelectric element unit of the wind power generator of FIG. 1.

3 to 6 are diagrams illustrating piezoelectric element parts having different shapes.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, but the present invention is not limited or limited by the embodiments. For reference, in the present description, the same numbers refer to substantially the same elements, and may be described by referring to the contents described in the other drawings under these rules, and the contents determined to be obvious to those skilled in the art or repeated may be omitted.

1 is a perspective view for explaining a wind power generator according to an embodiment of the present invention, Figure 2 is a cross-sectional view of the piezoelectric element of the wind power generator of FIG.

1 and 2, the wind power generator 100 includes a pressure change unit 110, a piezoelectric element unit 120, and a guide duct 130.

First, the piezoelectric element unit 120 includes a piezoelectric element 122 and a support member 124, the piezoelectric element 122 may generate electric power by generating electric polarization by a mechanical pressure such as strain (strain) Polyvinylidene fluoride (polyvinylidene fluoride), barium titanate, lead titanate, zirconate titanate, quartz (quartz) and the like can be prepared, and may be provided in a single layer or a multilayer structure depending on the material and the piezoelectric method. In this embodiment, it can be prepared using polyvinylidene fluoride (PVDF).

Pressure change may occur in the rear of the propeller, the fluttering flag, and the swinging object caused by the wind, and the piezoelectric element 122 repeatedly vibrates and generates power by regular or irregular pressure changes. You can.

However, as the vibration is repeated, the piezoelectric element 122 may be cracked due to stress due to prolonged use, and damage may occur due to foreign matter mixed in the wind. Accordingly, the support member 124 may be provided on one surface of the piezoelectric element 122 so as to be in close contact with the piezoelectric element 122 so as to minimize cracking due to stress. In the present embodiment, the support member 124 uses a polyester film (Mylar) resistant to plastic deformation, but may also use other synthetic resins having high hardness and not easily causing plastic deformation. Meanwhile, as illustrated in FIG. 2, the support member 124 may protect the piezoelectric element 122 from foreign matter mixed with the wind. As illustrated in FIG. 2, the support member 124 may face the piezoelectric element 122 facing the windy direction. It may be disposed on one side of, and in some cases may be disposed on both sides.

In the present embodiment, the piezoelectric element 122 may be provided to have a thickness of 110 μm, and the support member 124 may have a thickness of 127 μm. The piezoelectric element part 122 according to the present embodiment may have a physical property value as shown in Table 1 below. It can have

[Table 1] Properties of Piezoelectric Element

The guide duct 130 may guide the movement path of the wind inward. In addition, the guide duct 130 may be provided in the form of a funnel to guide the wind inward. Five piezoelectric element parts 120 may be provided along the inner surface of the guide duct 130, and a cantilever having one end coupled to the inner surface of the guide duct 130 to vibrate effectively by wind. It may be provided as. For reference, the number of the piezoelectric element units 120 may be changed, and the piezoelectric element units 120 may be connected in series to increase the magnitude of the produced voltage, and in some cases, the piezoelectric element ( The magnitude of the voltage may be adjusted by adjusting the thickness of 122).

On the other hand, in order to continuously generate power in the piezoelectric element 122, a stress must be transmitted to the piezoelectric element 122 repeatedly. Thus, the wind power generator 100 according to the present invention is provided with a pressure change means 110 to use the wind, but generally have a change in pressure according to the periodical time of the wind having a constant speed without significant change. .

The pressure changing means 110 may include a propeller 112 having a plurality of wings and a propeller coupling support 114 capable of coupling the propeller 112 to the inner surface of the guide duct 130. Of course, as described above, if it is moved or driven by the wind and can cause a pressure change in the surroundings, in addition to the propeller may be provided in a variety of forms, such as flags, windbreaks. Of course, the propeller may also have a parallel or vertical axis of rotation corresponding to the wind direction of the wind.

The piezoelectric element unit 120 may be located at the rear adjacent to the end of the propeller 112, and irregular wind is changed in time near the piezoelectric element unit 120 disposed on the wind path as if it is an alternating current. The vibration of the piezoelectric element unit 120 can be caused more regularly. In this embodiment, the propeller 112 may be disposed in front of the piezoelectric element unit 120 to more effectively induce regular or irregular vibration of the piezoelectric element unit 120.

Meanwhile, the production efficiency of electricity may vary according to the shape of the piezoelectric element unit 120. Hereinafter, an example of changing the shape of the piezoelectric element part of the wind power generator 100 described above and producing electric power using the same will be described in detail.

3 to 6 are diagrams illustrating piezoelectric element parts having various shapes that may be used in the wind power generator of the present invention.

The piezoelectric element unit 120 illustrated in FIG. 3 may be provided in a rectangular shape. The piezoelectric element part 120 having a rectangular shape is easily manufactured in the most basic shape and bonded to mass production.

Piezoelectric element portions of various shapes can be considered to increase the production efficiency of electricity. The present inventors can use computer analysis and actual experiment in the process of determining the shape of the piezoelectric element parts of different shapes shown in FIGS. 3 to 6 and the comparative analysis of the production efficiency of electricity of each piezoelectric element part.

The piezoelectric element portion 120 having a rectangular shape shown in FIG. 3 is a model first given for energy harvesting. A plurality of moving points are disposed on the surface of the piezoelectric element portion 120 provided two-dimensionally for computer analysis and shape optimization. The moving point may be a key point for determining the shape of the piezoelectric element unit 120.

The two-dimensional piezoelectric element unit 120 may be three-dimensionally reconfigured as shown in FIG. 3 through ANSYS, which is a structural analysis program. Then, the energy conversion factor (η) is calculated through the enci. The energy conversion factor is determined by the ratio of total electric energy (Ee) to work from external energy (W), and is expressed by Equation 1 below.

[Equation 1] calculation formula of the energy conversion factor

As described above, MATLAB (Matrix Laboratory) is a programming language that provides high-performance numerical calculation and visualization of results by integrating numerical analysis, matrix operation, signal processing, and simple graphic functions into energy conversion factors calculated through NSIs. MATLAB can then move the movement point toward the direction of greatest electrical energy.

That is, the shape of the piezoelectric element may be determined by disposing the moving point in the two-dimensional piezoelectric element portion and repeating the movement of the moving point in the three-dimensionally shaped piezoelectric element portion.

Hereinafter, a process of comparatively analyzing the production efficiency of electricity of the piezoelectric element portion will be described through static analysis considering the lift force acting on the piezoelectric element portion.

First, as shown in FIG. 3, the piezoelectric element portion 120 is changed from an initially given rectangular piezoelectric element portion 120 to an optimal shape as shown in FIG. 4 through the above-described process using Nsis and MATLAB. Can be.

For reference, the ratio of the width and length of the piezoelectric element portion 120 of FIG. 3 used in the simulation is 1: 5, the thickness of the piezoelectric element 122 is 110 μm, and the thickness of the support member 124 is 127 μm. .

The difference in pressure according to the wind speed (positive pressure) can be calculated from the following [Equation 2] assuming a pressure difference ΔP between the upper and lower ends of the propeller 112.

[Equation 2] calculation formula of lift

Assuming that the lift coefficient Cp is 1.4, the air density ρ is 1.169 kg / m3 at room temperature, and the fluid velocity V is wind speed 3.5 m / s, a pressure value of 20.04 Pa can be calculated.

As described above, due to the change in pressure according to the wind speed, the piezoelectric element unit 120 may vibrate, and the voltage generated when resonance occurs may be simulated.

Through the fixed analysis using the encis, it is possible to calculate the total electric energy (voltage), the voltage (voltage) of the piezoelectric element unit 120 of FIG. 3, in the optimal shape using the enci and MATLAB The piezoelectric element unit 220 may be implemented, and the total electrical energy and voltage of the piezoelectric element unit 220 of FIG. 4 may be calculated under the same conditions (lift).

The above calculation results are summarized in Table 2 below, and the total electrical energy of each of the piezoelectric element unit 120 which is the first model shown in FIG. 3 and the piezoelectric element unit 220 which is the optimal model shown in FIG. It is confirmed that the total electric energy and maximum voltage tend to increase as the total area of the piezoelectric element increases.

[Table 2] Comparison table of the first model and the best model

In addition, the piezoelectric element unit 220 of FIG. 4, which is an optimal model, is 1.76 times the total electric energy / total area and the maximum voltage is 1.3 when compared to the piezoelectric element unit 120 of FIG. 3. It is confirmed that there is a fold increase.

For reference, the piezoelectric element 220 of FIG. 4 is provided as a cantilever including a fixed end 222 and a free end 224. The first narrow portion 226 and the first wide portion 228 are formed from the fixed end 222, and the first narrow portion 226 has a smaller width than the fixed end 222, and the first wide portion 228. ) Is provided wider than the first narrow portion 226. The width is gradually decreased again while passing through the first wide portion 228, and the free end 224 is formed to have a smaller width than the first wide portion 228.

Of course, the width ratios of the fixed end 222, the first narrow portion 226, the first wide portion 228, and the free end 224 may be changed according to the surrounding environment, and the side surface of the piezoelectric element unit 220 may be changed. May be provided in a curved shape for a smooth change, but may also be provided in a straight form.

Fixed analysis as described above can be a simple and very convenient way of calculating the energy harvest in the piezoelectric element portion. However, in the actual energy harvesting process, the wind may continuously consider harmonic excitation.

Irregular wind flow through the propeller can be converted into a regular flow as if it is an alternating current, and this regularly converted wind flow can constantly provide regular harmonic stimulation to the piezoelectric element.

That is, in the fixed analysis described above, the analysis is performed assuming that the pressure change according to the wind speed is fixed, but in the dynamic analysis described below, the analysis is performed considering that the wind flow is a harmonic stimulus.

Dynamic analysis takes into account the damping effect. The piezoelectric element portion continuously generates electricity by the flow of air, in which two damping effects by the material and the air are affected.

First, the material damping effect due to the material is already determined and may not affect the resonance frequency. However, the air damping effect may cause a reduction in the resonance frequency of the vibrating piezoelectric element portion. By considering the air damping effect using the damping ratio of air, an optimal model can be implemented in harmonic situations where the resonance frequency changes.

However, since the air damping ratio is determined by various factors such as the shape, thickness, and surface area of the piezoelectric element, it is very difficult to obtain an accurate air damping ratio. For example, experiments have found an air damping ratio of 0.10875.

Specifically, first, through experiments, the highest voltage can be obtained from a rectangular piezoelectric element having a natural frequency of 42.724 Hz.

Next, in the harmonic situation, the theoretical maximum voltage is obtained using the piezoelectric element portion. In this process, if the damping effect is not considered in the harmonic situation, the theoretical maximum voltage theoretically is infinite because the natural frequency of the piezoelectric element continuously meets the excitation frequency from the wind flow such as alternating current.

For the reasons mentioned above, by varying and applying the expected air damping ratio, it is possible to eliminate the difference between the experimental and theoretical maximum voltage. This process results in an air damping ratio of 0.1875.

After that, the piezoelectric element portion having an ideal shape can be obtained in the harmonic situation by applying the air damping ratio.

In detail, the piezoelectric element unit 320 illustrated in FIG. 5 is an optimal shape without considering the damping effect in a harmonic situation, and FIG. 6 is a piezoelectric element unit 420 having an optimal shape considering the damping effect.

The piezoelectric element portion 320 of FIG. 5 is provided as a cantilever including a fixed end 322 and a free end 324. The first wide portion 328, the first narrow portion 326, and the second wide portion 329 are formed from the fixed end 322, and the first wide portion 328 is wider than the fixed end 322. The first narrow portion 326 is provided to be narrower than the first wide portion 328, and the second wide portion 329 is wider than the first narrow portion 326. The width is gradually decreased again while passing through the second wide portion 329, and the free end 324 is formed to be narrower than the second wide portion 329.

Of course, the width ratios of the fixed end 322, the first wide part 328, the first narrow part 326, the second wide part 329, and the free end 324 may be changed according to the surrounding environment. The side surface of the piezoelectric element unit 320 may be provided in a curved shape for smooth change, but may also be provided in a straight line.

The piezoelectric element portion 420 of FIG. 6 also includes a fixed end 422, a first wide portion 428, a first narrow portion 426, a second wide portion 429, and a free end 424, but with a width. The change ratio of may be distinguished from the piezoelectric element unit 320 of FIG. 5.

Table 3 below summarizes the electrical characteristics of the piezoelectric element parts shown in FIGS. 3, 5, and 6 in a harmonic situation.

[Table 3] Electrical characteristics of the piezoelectric element parts shown in FIGS. 3, 5, and 6 in harmonic situations

As shown in Table 3, the piezoelectric element portion 420 illustrated in FIG. 6, which is the best model in a harmonic situation, is compared with the rectangular piezoelectric element portion 120 illustrated in FIG. 3. energy / total area) has been increased by 1.58 times.

Since the above-described process is determined from analysis through a computer, the results of experiments by actually manufacturing the piezoelectric element parts will be described in detail below.

For the experiment, the piezoelectric element is manufactured to have a thickness of 110 μm and the support member is 127 μm, and each shape follows the shape of the piezoelectric element shown in FIGS. 3, 5, and 6.

The manufactured piezoelectric element part is applied to the wind power generator as shown in FIG. 1, and various electrical values are measured and summarized in Table 4 below.

[Table 4] Electrical values measured by applying the piezoelectric element parts shown in FIGS. 3, 5, and 6 to the wind power generator shown in FIG.

As shown in Table 4, the maximum power of the piezoelectric element portion having the optimal shape in the harmonic situation shown in FIG. 6 is (maximum Power). The calculated maximum power of the piezoelectric element portion 120 having the rectangular shape shown in FIG. Compared with the maximum power, the increase is 24.17%.

In summary, as shown in Fig. 3, the basic rectangular piezoelectric element portion is fixed to the guide duct, as shown in Fig. 4, considering only the lift analysis in the case of fixed analysis, that is, 3.5 m / s wind. It can be seen that it is preferable to be made in the shape of a vial having a narrow portion 226 having a reduced width between the end 222 and the free end 224 opposite the fixed end 222.

In addition, considering that the wind has a harmonic pressure (time-dependent pressure, such as alternating current), as shown in Figure 5, to the fixed end 322 and the fixed end 322 fixed to the guide duct It can be seen that it is preferable that the narrow portion 326 having a reduced width between the opposite free ends 324 is manufactured in the shape of a vial bottle positioned at the center of the piezoelectric element portion 320.

In addition, considering the air damping effect by the wind, it can be seen that the change to the shape shown in Figure 6 again has the best electrical production efficiency from the actual air flow, specifically, as shown in Figure 6 Similarly, the ratio of change in width between the fixed end 422 fixed to the guide duct and the free end 424 opposite to the fixed end 422 is wider than that shown in FIG. It can be seen that it is desirable to be manufactured in a reduced shape.

7 is a sectional view of a wind turbine according to another embodiment of the present invention.

Referring to FIG. 7, the wind power generator 500 may include a first power generation means and a second power generation means. The first power generation means includes a propeller 512 and an auxiliary power generation unit 540 for generating electricity in conjunction with the rotation axis of the propeller 512, the auxiliary power generation unit 540 is mounted to the propeller 512 as in the prior art And a stator 544 disposed around the rotation shaft 542 and the rotation shaft 542, and may generate electricity by the rotation of the rotation shaft 542. The stator 544 may be housed in a case 546 having an interior space for accommodating the stator 544, which may be coupled to the guide duct 530 by the generator coupling support 548. have.

The second power generation unit may include the piezoelectric element unit 520, and may include the other piezoelectric element unit 520 described above. In the present embodiment, the piezoelectric element unit 520 is composed of one set at the rear of the propeller 512, but may be provided as a plurality of sets overlapped along the movement path of the wind.

In general, the amount of power generated by the auxiliary power generation unit 540 using the rotor and the stator may be higher than the amount of power generated by the piezoelectric element unit 520. However, in the present embodiment, the piezoelectric element portion, that is, the second power generation means, can further generate power by using the pressure change by the first power generation means without physically affecting the first power generation means. In addition, the influence of the feedback back to the first power generation means in the power generation process by the second power generation means can be almost eliminated.

Therefore, the first power generation means using the propeller and the second power generation means using the piezoelectric element portion can build a dual wind power generation system, and the second power generation means can add its own power generation capacity in addition to the power generation capability of the first power generation means. The efficiency of electricity production of the overall power generation system can thus be increased.

In addition, such a wind power generation system can be usefully used in places where the power supply is not smooth. For example, it can provide continuous power to sensors mounted on large bridges or islands that are difficult to supply. Home power may not be enough, but it can effectively supply adequate power to operate sensors without changing batteries.

As described above, although described with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

The wind power generator and the dual wind power generation system according to the present invention can be widely used in an apparatus or system capable of producing electricity using wind power.

Claims

Pressure change means arranged on the movement path of the wind to generate a pressure change with time; And

A piezoelectric element unit disposed adjacent to the pressure change unit to generate electric power by the pressure change according to the time;

Wind power generator having a.
The method of claim 1,

The pressure change means is a wind turbine, characterized in that it comprises a propeller.
The method of claim 2,

The propeller is a wind turbine, characterized in that disposed in the front end of the piezoelectric element.
The method of claim 1,

It includes a funnel-shaped guide duct that provides a path of movement of the wind inwards,

The piezoelectric element portion is a wind power generator, characterized in that provided in the form of a cantilever beam provided at least one along the inner surface of the guide duct.
The method of claim 1,

The piezoelectric element unit is provided as a cantilever and a wind power generator, characterized in that provided in a rectangular form.
The method of claim 1,

The piezoelectric element portion is provided as a cantilever, and a first narrow portion narrower than the fixed end and a first wide portion wider than the first narrow portion are sequentially provided from the fixed end, and the free end is the first wide portion. Wind turbines, characterized in that formed to be narrower than the width.
The method of claim 1,

The piezoelectric element portion is provided as a cantilever and has a first wide portion wider than the fixed end from the fixed end, a first narrow portion narrower than the first wide portion, and a second wider portion than the first narrow portion. The wide section is provided in sequence, the free end is a wind power generator, characterized in that the width is formed narrower than the second wide section.
The method according to claim 6 or 7,

Wind turbines, characterized in that the side surface of the piezoelectric element portion is provided in a curved shape.
The method of claim 1,

The piezoelectric element unit comprises a piezoelectric element for generating electricity by the pressure change over time, and a support member bonded to the piezoelectric element.
The method of claim 9,

The piezoelectric element includes a polyvinylidene fluoride, and the support member comprises a polyester film.
The method of claim 1,

And a natural frequency of the piezoelectric element unit and a frequency of wind having a pressure change with time.
A first power generation means arranged on the movement path of the wind to generate a pressure change with time and generate electric power; And

And a second power generating means disposed adjacent to the first power generating means to generate electric power by the pressure change over time.
The method of claim 12,

The first power generation unit is a dual wind power generation system, characterized in that it comprises a propeller and an auxiliary power generation unit for generating electricity in conjunction with the rotating shaft of the propeller.
The method of claim 12,

And the second power generation means is disposed adjacent to the first power generation means and includes a piezoelectric element portion generating electric power by using a pressure change formed by the first power generation means.
The method of claim 14,

The piezoelectric element portion is a dual wind power generation system, characterized in that located behind the first power generating means.
The method of claim 12,

The piezoelectric element unit is provided as a cantilever, dual wind power generation system, characterized in that provided in a rectangular form.
The method of claim 12,

The piezoelectric element portion is provided as a cantilever, and a first narrow portion narrower than the fixed end and a first wide portion wider than the first narrow portion are sequentially provided from the fixed end, and the free end is the first wide portion. Dual wind power generation system characterized in that the narrower than the width.
The method of claim 12,

The piezoelectric element portion is provided as a cantilever and has a first wide portion wider than the fixed end from the fixed end, a first narrow portion narrower than the first wide portion, and a second wider portion than the first narrow portion. The wide part is provided in sequence, the free end is dual wind power generation system, characterized in that the width is formed narrower than the second wide part.
The method of claim 17 or 18,

Dual wind power generation system, characterized in that the side of the piezoelectric element portion is provided in a curved shape.