A piezoelectric forward and reverse effect coupling power amplification device for wind turbine blades

Abstract

The present invention discloses a piezoelectric forward and reverse effect coupled power amplification device for a wind turbine blade. The device comprises an upper flexible piezoelectric material, a lower flexible piezoelectric material, a housing, a converter, an energy storage device, and a controller. The lower flexible piezoelectric material is mounted on the lower portion of the housing, which is fixed to the wind turbine blade. The strain energy generated by the wind turbine blade drives the deformation of the lower flexible piezoelectric material, thereby causing the lower flexible piezoelectric material to generate a current signal. This current signal is stored in the energy storage device after passing through the converter. At the same time, the controller detects the current signal and, when the current signal strength meets a predetermined value, controls the energy storage device to energize the upper flexible piezoelectric material. This causes the upper flexible piezoelectric material to deform through the reverse piezoelectric effect, disturbing the flow field outside the boundary layer of the wind turbine blade and suppressing boundary layer separation. The present invention can effectively improve the aerodynamic efficiency of the wind turbine blade root while being safe and reliable, having a simple structure, and being easy for construction personnel to operate.

Description

Technical Field

[0001] The invention relates to a piezoelectric forward and reverse effect coupling power amplification device for a wind turbine blade, belonging to the field of wind turbine generator design and application. Background Art

[0002] Wind energy is a clean and stable renewable energy source. The Earth possesses abundant wind energy resources, and the strategic importance of wind power is recognized worldwide. However, if wind energy efficiency cannot be improved and electricity costs reduced, wind power developers will face severe pressure. Against this backdrop, further reducing the cost of wind power through technological advancement and innovation is an urgent need for the wind power industry.

[0003] As wind energy capture components, the aerodynamic performance of blades affects the turbine's power generation. Currently, the aerodynamic shape of conventional wind turbine blades cannot fully achieve ideal aerodynamic flow conditions. For example, due to structural considerations, the root chord length of wind turbine blades cannot be too large. This results in a nearly circular shape closest to the root, with a relative thickness exceeding 60%. This leads to a certain degree of separation zone at the root, and the lift coefficient may be negative at small angles of attack. This non-ideal state prevents local areas of the blade surface from achieving their maximum aerodynamic efficiency potential, reducing the overall power output. Flow control targeting areas of the blade surface with non-ideal flow to compensate for the reduced aerodynamic efficiency within a certain range and thereby increase the wind turbine's power output has been a research hotspot in recent years. Numerous flow control methods and aerodynamic efficiency enhancement measures have garnered attention from experts, scholars, and industry professionals, such as tip winglets, vortex generators, plasma synthetic jets, and blade root spoilers. In parallel with flow control research, research on wind-based environmental energy harvesters is also a hot topic. The wind-induced vibration effect involves converting ambient wind energy into vibration energy through various means, which is then converted into electrical energy through piezoelectric, magnetoelectric, and magnetostrictive effects. Due to its advantages of simple structure, high output voltage, and high power density, the piezoelectric effect is often used to convert energy into electrical energy, making it a major research area in wind-induced vibration energy harvesting. Summary of the Invention

[0004] The purpose of the present invention is to solve the problems mentioned in the background technology. The present invention proposes a piezoelectric forward and reverse effect coupling power amplification device for wind turbine blades. By combining flow control and piezoelectric effect, the aerodynamic efficiency of the wind turbine blade root can be effectively improved. At the same time, it is safe and reliable, has a simple structure, and is easy for construction personnel to operate.

[0005] In order to achieve the above technical objectives, the technical solution adopted by the present invention is:

[0006] A piezoelectric forward and reverse effect coupled power amplification device for a wind turbine blade, comprising: an upper flexible piezoelectric material, a lower flexible piezoelectric material, a shell, an inverter, an energy storage device and a controller; the lower flexible piezoelectric material is mounted on the lower portion of the shell, the shell is fixed to the wind turbine blade, the upper flexible piezoelectric material is fixedly mounted on the upper portion of the shell, the lower flexible piezoelectric material is connected to the inverter and the controller respectively, the inverter is connected to the energy storage device, the energy storage device is connected to the controller and the upper flexible piezoelectric material respectively; the strain energy generated by the wind turbine blade drives the lower flexible piezoelectric material to deform, thereby causing the lower flexible piezoelectric material to generate a current signal, which is stored in the energy storage device after passing through the inverter; at the same time, the controller detects the current signal, and when the current signal strength meets a predetermined value, the controller controls the energy storage device to energize the upper flexible piezoelectric material, causing the upper flexible piezoelectric material to deform through the reverse piezoelectric effect, thereby disturbing the flow field outside the boundary layer of the wind turbine blade and suppressing the separation of the boundary layer.

[0007] To optimize the above technical solutions, specific measures taken also include:

[0008] The above-mentioned upper flexible piezoelectric material is composed of a stack of multiple layers of piezoelectric materials in the direction perpendicular to the blade, and is composed of multiple flexible piezoelectric segments arranged in series in the span direction of the blade. Each flexible piezoelectric segment is connected to an energy storage device respectively. The controller can control the energy storage device to periodically energize each flexible piezoelectric segment respectively, thereby causing the upper flexible piezoelectric material to deform. The deformation action direction is perpendicular to the blade surface and upward, and the upper flexible piezoelectric material produces periodic deformation according to a given law between the initial position and the maximum deformation h, where h is an extremely small amount.

[0009] The above-mentioned piezoelectric forward and reverse effect coupling power amplification device also includes a transition section, a base, a main supporting web and a secondary supporting web. The base is a thin plate structure with the same curvature as the blade surface. The base is fixed to the blade surface by gluing. The shell is fixed on the base. A rectangular groove is provided on the upper part of the shell. An internal cavity is provided inside the shell. Transition sections are provided on both sides and both ends of the shell. The upper flexible piezoelectric material is fastened in the rectangular groove on the upper part of the shell. The lower flexible piezoelectric material is fastened in the lower part of the internal cavity and is separated from the upper part of the internal cavity by a partition. The secondary supporting web is installed on both sides of the internal cavity. The main supporting web is installed in the transition section. The converter, energy storage device and controller are fastened in the upper part of the internal cavity.

[0010] The length of the above-mentioned piezoelectric forward and reverse effect coupling power amplification device is 5%R--10%R, and the installation position is on the suction surface of the blade root. The chord-wise installation position is 20%C to 30%C from the leading edge, and the installation position close to the blade root is at 20%C. The span-wise installation area is 10%R to 20%R from the blade root, and the height is equal to the boundary layer height at the blade root. R is the blade length, and C is the chord length at the blade root.

[0011] The transition section is filled with light foam material.

[0012] The controller is connected to a remote control chip, which can receive signals transmitted by a remote computer. When the remote control chip receives the signals transmitted by the remote computer, the remote control chip will transmit the signals to the controller.

[0013] The controller can control each flexible piezoelectric segment to perform periodic motion according to a sine function or a cosine function.

[0014] When the controller controls the deformation of the flexible piezoelectric material, the signals received by each two adjacent flexible piezoelectric segments are in different phases.

[0015] The shell is a long hollow structure.

[0016] The working principle of the present invention is as follows:

[0017] When the wind turbine is running, the strain at the blade root is the largest. The power amplification device is installed at the blade root. The strain at the blade root will drive the lower flexible piezoelectric material in the power amplification device installed close to the blade surface to deform. At this time, the positive piezoelectric effect of the lower flexible piezoelectric material can be used to generate current, which is converted by the converter and then transmitted to the energy storage device.

[0018] The power amplification device can also receive signals from a remote computer via a remote control chip. The received signals control whether to utilize the upper flexible piezoelectric material's inverse piezoelectric effect to suppress aerodynamic separation. When the remote computer signals that aerodynamic separation at the blade root should be suppressed, the controller controls the energy storage device to energize the upper flexible piezoelectric material. This inverse piezoelectric effect causes each section of the upper flexible piezoelectric material to periodically deform, perpendicular to the blade surface and upward. This deformation disrupts the flow field outside the boundary layer, injecting energy from outside the boundary layer into the boundary layer, thereby suppressing separation within the boundary layer.

[0019] The present invention has the following characteristics:

[0020] (1) The piezoelectric forward and reverse effect coupling power amplification device of the wind turbine blade is installed at the root of the wind turbine blade, so that the strain generated at the root of the blade during the operation of the wind turbine can drive the flexible piezoelectric material to deform, and the current is generated by the positive piezoelectric effect and transmitted to the energy storage device through the converter. The power amplification device does not need to consume external energy.

[0021] (2) The piezoelectric forward and reverse effect coupling power amplification device of the wind turbine blade uses the reverse piezoelectric effect to make the flexible piezoelectric material produce a deformation perpendicular to the blade surface after the remote control chip receives the signal transmitted by the remote computer, thereby disturbing the flow field outside the boundary layer, injecting the energy outside the boundary layer into the boundary layer, and suppressing the aerodynamic separation of the blade root.

[0022] (3) The piezoelectric forward and reverse effect coupled power amplification device of the wind turbine blade utilizes the reverse piezoelectric effect of the flexible piezoelectric material to disturb the flow. The deformation law of the flexible piezoelectric material is controlled by the controller and can be expressed in various forms such as sine function or cosine function. The air is blocked by the flexible piezoelectric material that deforms periodically and alternately according to a certain law. The separation effect when flowing through the power amplification device is better, and the effect of suppressing the separation area of ​​the blade root is more obvious.

[0023] (4) The piezoelectric forward and reverse effect coupled power amplification device of the wind turbine blade uses a remote control chip. The deformation of the flexible piezoelectric material in the power amplification device is controlled by a signal given by a remote computer. This remote control capability makes the power amplification device suitable for a variety of working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the structure of a flexible spoiler device at the root of a wind turbine blade using the positive and negative piezoelectric effects.

[0025] Figure 2 This is a partial enlarged view of the AA section.

[0026] Figure 3 This is a partial enlarged view of the BB section.

[0027] Figure 4 Schematic diagram of the deformation of flexible piezoelectric material in BB.

[0028] Names marked in the figure: upper flexible piezoelectric material 1, lower flexible piezoelectric material 2, shell 3, transition section 4, base 5, internal cavity 6, main supporting web 7, secondary supporting web 8, converter 9, energy storage device 10, remote control chip 11, controller 12, partition 13. DETAILED DESCRIPTION

[0029] The embodiments of the present invention are described in further detail below with reference to the accompanying drawings.

[0030] like Figure 1 As shown, the piezoelectric forward and reverse effect coupling power amplifier device for a wind turbine blade according to the present invention has a length of 5%R-10%R and is installed on the suction side of the blade root. The chordwise installation position is 20%C to 30%C from the leading edge, and the installation position close to the blade root is 20%C. The spanwise installation area is within the range of 10%R to 20%R from the blade root. The power amplifier device height is equal to the boundary layer height at the blade root. The blade length is R, and the chord length at the blade root is C.

[0031] like Figure 2 and Figure 3As shown, the power amplification device provided by the present invention is composed of an upper flexible piezoelectric material 1, a lower flexible piezoelectric material 2, a shell 3, a transition section 4, a base 5, an internal cavity 6, a main supporting web 7, a secondary supporting web 8, an inverter 9, an energy storage device 10, a remote control chip 11, a controller 12, and a partition 13.

[0032] When the wind turbine is running, the strain at the blade root is the largest. The power amplification device is installed at the blade root. The strain at the blade root will drive the lower flexible piezoelectric material 2 in the power amplification device installed close to the blade surface to deform. At this time, the positive piezoelectric effect of the lower flexible piezoelectric material 2 can be used to generate current. After the current is converted by the converter 9, the current is transmitted to the energy storage device 10; at the same time, the power amplification device can receive a signal from a remote computer through a remote control chip 11, and control whether to use the inverse piezoelectric effect of the flexible piezoelectric material to suppress aerodynamic separation based on the received signal. When the signal given by the remote computer needs to suppress the aerodynamic separation at the blade root, the remote control chip 11 will transmit the signal to the controller 12, and the controller 12 will control the energy storage device 10 to energize the upper flexible piezoelectric material 1, and use the inverse piezoelectric effect of the piezoelectric material to make each section of the upper flexible piezoelectric material 1 produce periodic deformation. The deformed upper flexible piezoelectric material 1 can disturb the flow field outside the boundary layer and inject energy outside the boundary layer into the boundary layer, thereby suppressing the separation of the boundary layer and improving the aerodynamic efficiency of the blade root.

[0033] The upper flexible piezoelectric material 1 is woven from multiple layers of flexible piezoelectric material in a direction perpendicular to the blade, and its cross-section can be in various shapes such as rectangular and trapezoidal. The upper flexible piezoelectric material 1 is firmly installed in the upper rectangular groove of the shell 3. To prevent fatigue and fracture damage, it is composed of multiple sections arranged in series in the span direction of the blade, and the height of each section is 0.1 to 0.5 times the height of the power amplification device; the deformation direction of the upper flexible piezoelectric material 1 is perpendicular to the blade surface and upward. When the deformation is controlled by the controller, each section of the upper flexible piezoelectric material 1 produces periodic deformation according to a given law between the initial position and the maximum deformation h, and h is an extremely small amount.

[0034] The lower flexible piezoelectric material 2 is fixedly mounted below the inner cavity 6 of the housing and is also composed of multiple layers of woven flexible piezoelectric material. The lower flexible piezoelectric material 2 is separated from the inner cavity 6 by a spacer 13 .

[0035] The shell 3 is a hollow structure with a long raised strip. The hollow shell has a certain rigidity and reduces the weight of the structure. The shell 2 is fixed on the base 5.

[0036] The base 5 is a thin plate structure with the same curvature as the blade surface, and the base 5 is installed on the blade surface by gluing or other methods.

[0037] In order to maintain the continuity of the flow field at the blade root, transition sections 4 are provided on both sides and ends of the shell 3. The transition sections 4 are filled with lightweight foam and are installed with main supporting webs 8 to maintain the shape and increase the anti-buckling ability.

[0038] like Figure 3 As shown, the converter 9, energy storage device 10, remote control chip 11, and controller 12 are fastened in the internal cavity 6 of the shell; in order to facilitate heat dissipation, the internal cavity 6 is not filled with filler; at the same time, secondary supporting webs 8 are installed on both sides of the internal cavity 6 to maintain the shape of the internal cavity 6 and provide support for the upper flexible piezoelectric material 1.

[0039] The current converted by the lower flexible piezoelectric material 2 is converted by the converter 9 and then transmitted to the energy storage device 10. The energy storage device 10 can not only store the electric energy converted by the lower flexible piezoelectric material 2 using the positive piezoelectric effect, but also supply power to the upper flexible piezoelectric material 1 when deformed using the inverse piezoelectric effect.

[0040] The controller 12 is used to control the deformation law of each section of flexible piezoelectric material when it is deformed using the inverse piezoelectric effect. The remote control chip 11 can receive signals from a remote computer and transmit signals to the controller 12. When the controller 12 receives the signal transmitted by the remote control chip 11, it will control the upper flexible piezoelectric material 1 to produce periodic deformation according to a given deformation law. The deformation law is expressed in the form of a sine function, a cosine function, etc. The effect of the upper flexible piezoelectric material 1 that produces periodic deformation on disturbing the fluid outside the boundary layer is more obvious.

[0041] like Figure 4 As shown, when the upper flexible piezoelectric material 1 is controlled by the controller 12 to produce periodic deformation, the deformation signals received by each two adjacent upper flexible piezoelectric materials 1 are in different phases, such as the phase difference Phase: When a section of flexible piezoelectric material is deformed to the maximum deformation height h during deformation, the two adjacent sections of piezoelectric material are at their initial positions, or when a section of piezoelectric material is at its initial position, the two adjacent sections of piezoelectric material are at their maximum deformation h.

[0042] Compared with the current flow control technology, the piezoelectric forward and reverse effect coupling power amplification device of the wind turbine blade of the present invention enhances the flow disturbance effect of the power amplification device and increases the active control of the power amplification device. At the same time, research has shown that the flexible flow disturbance device has obvious effect in suppressing flow separation, is simple to install, and is suitable for use on wind turbines.

[0043] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions based on the principles of the present invention are within the scope of protection of the present invention. It should be noted that for those skilled in the art, various improvements and modifications that do not depart from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A piezoelectric forward and reverse effect coupling power amplification device for a wind turbine blade, characterized by: The invention is composed of an upper flexible piezoelectric material (1), a lower flexible piezoelectric material (2), a shell (3), a converter (9), an energy storage device (10) and a controller (12), wherein the lower flexible piezoelectric material (2) is installed at the lower part of the shell (3), the shell (3) is fixed on the wind turbine blade, the upper flexible piezoelectric material (1) is fixedly installed at the upper part of the shell (3), the lower flexible piezoelectric material (2) is respectively connected to the converter (9) and the controller (12), the converter (9) is connected to the energy storage device (10), and the energy storage device (10) is respectively connected to the controller (12) and the upper flexible piezoelectric material (1 ) are connected, the strain energy generated by the wind turbine blade drives the deformation of the lower flexible piezoelectric material (2), and the positive piezoelectric effect is used to make the lower flexible piezoelectric material (2) generate a current signal, and the current signal is stored in the energy storage device (10) after passing through the converter (9). At the same time, the controller (12) detects the current signal, and when the current signal intensity meets the predetermined value, the controller (12) controls the energy storage device (10) to energize the upper flexible piezoelectric material (1), so that the upper flexible piezoelectric material (1) is deformed by the inverse piezoelectric effect, thereby disturbing the flow field outside the boundary layer of the wind turbine blade and suppressing the separation of the boundary layer; The upper flexible piezoelectric material (1) is composed of a stack of multiple layers of piezoelectric materials in a direction perpendicular to the blade, and is composed of multiple flexible piezoelectric segments arranged in series in the blade span direction, and the height of each segment is 0.1 to 0.5 times the height of the power amplification device. Each flexible piezoelectric segment is connected to the energy storage device (10) respectively. The controller (12) can control the energy storage device (10) to periodically energize each flexible piezoelectric segment respectively, thereby causing the upper flexible piezoelectric material (1) to deform. The deformation action direction is perpendicular to the blade surface and upward, and the upper flexible piezoelectric material (1) is periodically deformed according to a given rule between the initial position and the maximum deformation h, where h is a very small amount. The piezoelectric forward and reverse effect coupling power amplification device also includes a transition section (4), a base (5), a main supporting web (8) and a secondary supporting web (7). The base (5) is a thin plate structure with a curvature consistent with the blade surface. The base (5) is fixed to the blade surface by gluing. The shell (3) is fixed on the base (5). The upper part of the shell (3) is provided with a rectangular groove. The interior of the shell (3) is provided with an internal cavity (6). The shell (3) is provided with transition sections (4) on both sides and both ends. The upper flexible piezoelectric material (1) is fastened in the rectangular groove on the upper part of the shell (3). The lower flexible piezoelectric material (2) is fastened in the lower part of the internal cavity (6) and is separated from the upper part of the internal cavity (6) by a partition (13). The secondary supporting web (8) is installed on both sides of the internal cavity (6). The main supporting web (7) is installed in the transition section (4). The converter (9), the energy storage device (10) and the controller (12) are fastened in the upper part of the internal cavity (6).

2. The piezoelectric forward and reverse effect coupling power amplification device for wind turbine blades according to claim 1 is characterized in that: The length of the forward and reverse effect coupling power amplification device is 5%R-10%R, and the installation position is on the suction surface of the blade root. The chord-wise installation position is 20%C to 30%C from the leading edge, and the installation position close to the blade root is at 20%C. The span-wise installation area is 10%R to 20%R from the blade root. The height is equal to the boundary layer height at the blade root. R is the blade length and C is the chord length at the blade root.

3. The piezoelectric forward and reverse effect coupling power amplification device for a wind turbine blade according to claim 1, characterized in that: The transition section (4) is filled with light foam material.

4. The piezoelectric forward and reverse effect coupling power amplification device for a wind turbine blade according to claim 1, characterized in that: The controller (12) is connected to a remote control chip (11), and the remote control chip (11) can receive a signal transmitted by a remote computer. When the remote control chip (11) receives the signal transmitted by the remote computer, the remote control chip (11) will transmit the signal to the controller (12).

5. The piezoelectric forward and reverse effect coupling power amplification device for a wind turbine blade according to claim 1, characterized in that: The controller (12) can control each flexible piezoelectric segment to perform periodic motion according to a sine function or a cosine function.

6. The piezoelectric forward and reverse effect coupling power amplification device for a wind turbine blade according to claim 1, characterized in that: When the controller (12) controls the upper flexible piezoelectric material (1) to deform, the signals received by each two adjacent flexible piezoelectric segments are in different phases.

7. The piezoelectric forward and reverse effect coupling power amplification device for a wind turbine blade according to claim 1, characterized in that: The shell (3) is a long hollow structure.

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