Piezoelectric wave energy acquisition device based on C-shaped cantilever beam

Abstract

The invention discloses a piezoelectric wave energy collecting device based on a C-shaped cantilever beam, which comprises a shell, a fixed shaft, a turntable, a first magnet, a pendulum bob, the C-shaped piezoelectric cantilever beam and a second magnet, and is characterized in that the fixed shaft is vertically fixed in the sealed shell, and the turntable is coaxially arranged on the fixed shaft in a rotatable manner; a plurality of first magnets are evenly arranged on the rotary disc in the circumferential direction of the rotary disc, the magnetic poles of the adjacent first magnets are opposite, the pendulum bob is arranged on the rotary disc, a plurality of sets of C-shaped piezoelectric cantilever beams are evenly arranged on the fixed shaft in the circumferential direction of the fixed shaft, one ends of the C-shaped piezoelectric cantilever beams are arranged on the fixed shaft, and the other ends of the C-shaped piezoelectric cantilever beams are arranged below the first magnets. And a second magnet is arranged at the end part of the C-shaped piezoelectric cantilever beam. The device has the advantages that multi-direction wave energy collection can be achieved, large-amplitude deformation can be generated more easily under ultralow-frequency wave excitation, and the C-shaped piezoelectric cantilever beam can generate large-amplitude deformation under stirring of alternate change of magnetic poles, so that the electric energy output effect of the device is enhanced.

Description

Technical Field

[0001] The invention relates to the technical field of wave energy power generation, and in particular to a piezoelectric wave energy collection device based on a C-shaped cantilever beam. Background Art

[0002] The ocean is rich in resources, and monitoring and scientific research on the marine environment are of great strategic significance and scientific value. Due to the complexity and unknown nature of the marine environment, it is often impossible to charge and maintain marine equipment in a timely manner, so the endurance of marine equipment is particularly important. At present, marine equipment often carries energy sources such as batteries or uses solar energy for power supply. However, due to the size of the marine equipment itself, if it is equipped with a large-capacity battery, its working efficiency and internal space will be greatly limited. If solar power is used, rainy weather will greatly affect the power generation efficiency. Wave energy is one of the directly usable marine energy sources. If wave energy is converted into electrical energy and becomes a power source for microelectronic equipment in the marine environment, its endurance can be improved. Due to its electromechanical coupling direct conversion characteristics, piezoelectric energy harvesters show unique advantages in wave energy micro-power scenarios such as marine sensor networks and buoy power supply.

[0003] At present, most piezoelectric energy harvesters only collect vibration energy in a single direction. Due to the multi-directional characteristics of wave motion, their output power is limited to a certain extent. How to achieve multi-directional wave energy collection while enhancing the power output of piezoelectric energy harvesters under ultra-low frequency (less than 1Hz) wave excitation is still a difficulty. Although the Chinese invention patent document with publication number CN110492788A discloses a piezoelectric-electromagnetic coupled up-conversion multi-directional vibration energy harvesting device, the effective working frequency band of the energy harvester is improved by piezoelectric-electromagnetic coupling resonance, and the up-conversion composite vibration is used to solve the problem of low energy harvesting efficiency of the energy harvesting device under random swinging of the human body, the vibration frequency is much greater than 1Hz, and it is impossible to achieve power output under ultra-low frequency (less than 1Hz) wave excitation. Summary of the invention

[0004] The technical problem to be solved by the present invention is how to achieve multi-directional wave energy collection while enhancing the electrical energy output of the piezoelectric energy harvester under ultra-low frequency wave excitation.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] A piezoelectric wave energy collection device based on a C-shaped cantilever beam comprises a shell, a fixed shaft, a turntable, a first magnet, a pendulum, a C-shaped piezoelectric cantilever beam and a second magnet. The fixed shaft is vertically fixed inside a sealed shell. The turntable is rotatably arranged coaxially on the fixed shaft. A plurality of first magnets are evenly arranged on the turntable along its circumferential direction. The magnetic poles of adjacent first magnets are opposite. The pendulum is arranged on the turntable. A plurality of groups of C-shaped piezoelectric cantilever beams are evenly arranged on the fixed shaft along its circumferential direction. One end of the C-shaped piezoelectric cantilever beam is arranged on the fixed shaft, and the other end is arranged below the first magnet. The end of the C-shaped piezoelectric cantilever beam arranged below the first magnet is arranged with a second magnet.

[0007] The rotation of the pendulum in the collection device can make the collection device respond to wave excitations in multiple directions, capture wave energy in multiple directions, and realize wave energy collection in multiple directions. A plurality of first magnets are installed on the turntable, so that one rotation of the turntable can cause the C-shaped piezoelectric cantilever beam to be moved multiple times, thereby enhancing the effect of up-conversion. In addition, the dynamic matching of the nonlinear stiffness characteristics of the C-shaped piezoelectric cantilever beam and the pendulum excitation significantly broadens the effective working frequency band of the system. At the same time, compared with the traditional cantilever beam, the natural frequency of the C-shaped piezoelectric cantilever beam structure is significantly lower, and it is easier to produce large deformation under ultra-low frequency wave excitation.

[0008] In addition, arranging the magnetic poles of adjacent first magnets in opposite directions can increase the range of magnetic force variation. Under the influence of the alternating magnetic poles, the C-shaped piezoelectric cantilever beam can produce a large deformation, thereby enhancing its power output effect.

[0009] Preferably, the turntable includes a turntable body and a fixed column, a plurality of first magnets are evenly arranged along the circumferential direction of the turntable body, a fixed column is arranged at the center of the turntable body, a rotating through hole for allowing the fixed shaft to pass through is opened in the center of the turntable body and the fixed column, bearings for mounting the fixed shaft are arranged at the upper and lower ends of the rotating through hole, one end of the pendulum is arranged on the fixed column, and the swing of the pendulum drives the turntable to rotate on the fixed shaft.

[0010] Preferably, a boss is provided on the outer wall of the fixed column, and a slot matching the horizontal cross-sectional shape of the fixed column is provided at one end of the pendulum, so that the swing of the pendulum can drive the turntable body to rotate on the fixed axis.

[0011] Preferably, the turntable body is evenly provided with mounting through holes corresponding to the number of the first magnets along its circumferential direction, a first magnet is installed in each mounting through hole, and the heights of adjacent first magnets are staggered.

[0012] Preferably, six first magnets are evenly arranged on the turntable body along its circumferential direction.

[0013] Preferably, the first magnet is a cylindrical magnet.

[0014] Preferably, the pendulum is a 120° sector-shaped block structure.

[0015] Preferably, a support seat is also provided at the top of the fixed shaft, and one end of the C-shaped piezoelectric cantilever beam is fixedly connected to the support seat.

[0016] Preferably, the C-shaped piezoelectric cantilever beam includes an upper piezoelectric vibrator, a middle piezoelectric vibrator, a lower piezoelectric vibrator and a connecting block, the two ends of the middle piezoelectric vibrator are respectively connected to the upper piezoelectric vibrator and the lower piezoelectric vibrator through connecting blocks, the end of the upper piezoelectric vibrator away from the middle piezoelectric vibrator is connected to the fixed axis, and the second magnet is arranged at the end of the lower piezoelectric vibrator away from the middle piezoelectric vibrator.

[0017] Preferably, the number of the C-shaped piezoelectric cantilever beams is three groups.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The collection device can capture multi-directional wave energy and realize multi-directional wave energy collection. Compared with the traditional cantilever beam, the C-shaped piezoelectric cantilever beam structure is more likely to produce a large deformation under ultra-low frequency wave excitation. In addition, the method of arranging the magnetic poles of adjacent first magnets in opposite directions can increase the range of magnetic force variation. Under the alternating magnetic poles, the C-shaped piezoelectric cantilever beam can produce a large deformation, thereby enhancing its power output effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of an embodiment of the present invention;

[0021] Figure 2 It is a schematic diagram of a local structure of an embodiment of the present invention;

[0022] Figure 3 is a top view of a turntable according to an embodiment of the present invention;

[0023] Figure 4 is a cross-sectional view of a turntable according to an embodiment of the present invention;

[0024] Figure 5 This is an experimental data diagram of the effect of different magnetic pole arrangements on the magnetic force exerted on a square magnet in an embodiment of the present invention;

[0025] Figure 6 This is an experimental data diagram of the influence of different magnetic pole arrangements on voltage output in an embodiment of the present invention;

[0026] Figure 7 Graph showing experimental data of power output under different external impedances in an embodiment of the present invention;

[0027] Figure 8 This is a voltage curve diagram when two thermo-hygrometers are powered at the same time in an embodiment of the present invention;

[0028] Figure 9 This is the state diagram when the full-bridge rectifier conversion circuit and the thermometer and hygrometer in the embodiment of the present invention operate stably. Detailed implementation manners

[0029] To facilitate those skilled in the art to understand the technical solution of the present invention, the technical solution of the present invention will be further described below with reference to the accompanying drawings of the specification.

[0030] In this application, unless otherwise clearly defined and limited, the terms "installed", "connected", "connected", "fixed", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection, an electrical connection, or a communication connection; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0031] In this application, unless otherwise clearly defined and limited, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of this application, the meaning of "a plurality" is two or more, unless otherwise clearly and specifically limited.

[0032] Refer to Figure 1 and Figure 2 , this embodiment discloses a piezoelectric wave energy harvesting device based on a C-shaped cantilever beam, which includes a housing 1, a fixed shaft 2, a turntable 3, a first magnet 4, a pendulum 5, a support base 6, a C-shaped piezoelectric cantilever beam 7, and a second magnet 8.

[0033] The housing 1 is a sealed cylindrical housing with a middle hole inside, and the fixed shaft 2 is vertically fixed on the inner bottom wall of the housing 1.

[0034] The turntable 3 is coaxially arranged on the fixed shaft 2 and can rotate. Specifically, refer to Figure 3 and Figure 4 , the turntable 3 includes a turntable body 31 and a fixed column 32. A plurality of first magnets 4 are evenly arranged along the circumferential direction of the turntable body 31, and the magnetic poles of adjacent first magnets 4 are opposite. In this embodiment, 6 first magnets 4 are provided, and the first magnets 4 are cylindrical magnets; a fixed column 32 is arranged at the center of the top surface of the turntable body 31. A rotation through hole 301 that can allow the fixed shaft 2 to pass through is provided at the centers of the turntable body 31 and the fixed column 32, and bearings 9 sleeving the fixed shaft 2 are provided at both the upper and lower ends of the rotation through hole 301.

[0035] One end of the pendulum 5 is arranged on the fixed column 32, and the other end is arranged away from the fixed column 32. The rotation of the turntable 3 on the fixed shaft 2 is driven by the swing of the pendulum 5. In this embodiment, the pendulum is a 120° sector block structure.

[0036] Furthermore, a boss 321 is arranged on the outer wall of the fixed column 32. One end of the pendulum 5 is provided with a slot hole that matches the shape of the horizontal section of the fixed column 32. The pendulum 5 is sleeved on the fixed column 32 through the slot hole. Under the cooperation of the boss 321 and the slot hole, the swing of the pendulum 5 can drive the turntable body 31 to rotate on the fixed shaft 2.

[0037] Furthermore, mounting through holes 311 corresponding to the number of the first magnets 4 are evenly arranged on the turntable body 31 along its circumferential direction, and each mounting through hole 311 is provided with a first magnet 4.

[0038] The support base 6 is fixed at the top of the fixed shaft 2. Three groups of C-shaped piezoelectric cantilever beams 7 are evenly arranged on the support base 6 along the circumferential direction of the fixed shaft 2. The included angle between adjacent C-shaped piezoelectric cantilever beams 7 is 120°. The opening direction of each group of C-shaped piezoelectric cantilever beams 7 is arranged towards the fixed shaft 2. Specifically, one end of each group of C-shaped piezoelectric cantilever beams 7 is fixedly connected to the support base 6, and the other end is arranged below the first magnet 4. Second magnets 8 are bonded to the ends of the C-shaped piezoelectric cantilever beams 7 arranged below the first magnet 4 for responding to the rotational excitation of the first magnet 4. In this embodiment, the second magnet 8 is a square magnet.

[0039] Furthermore, the C-shaped piezoelectric cantilever beam 7 includes an upper piezoelectric vibrator 71, a middle piezoelectric vibrator 72, a lower piezoelectric vibrator 73 and a connecting block 74. The two ends of the middle piezoelectric vibrator 72 are respectively connected to the upper piezoelectric vibrator 71 and the lower piezoelectric vibrator 73 through the connecting block 74 to form a C-shaped structure. The end of the upper piezoelectric vibrator 71 away from the middle piezoelectric vibrator 72 is connected to the support base 6, and the second magnet 8 is bonded to the end of the lower piezoelectric vibrator 73 away from the middle piezoelectric vibrator 72.

[0040] Still further, the upper piezoelectric vibrator 71, the middle piezoelectric vibrator 72 and the lower piezoelectric vibrator 73 are all rectangular piezoelectric vibrators with the same size, and all of them are composed of a layer of beryllium bronze substrate and a layer of lead zirconate titanate (PZT).

[0041] The working principle of this embodiment is:

[0042] Float the collection device on the water surface. When the wave moves, the housing 1 tilts. Under the action of gravity, the pendulum 5 rotates. While the pendulum 5 rotates, it drives the turntable body 31 to rotate. When the first magnet 4 on the turntable body 31 approaches and then crosses the second magnet 8 at the end of the C-shaped piezoelectric cantilever beam 7 below it, through the action of non-contact magnetic force, it will produce a similar plucking effect on the C-shaped piezoelectric cantilever beam 7, so that the C-shaped piezoelectric cantilever beam 7 vibrates and deforms. According to the direct piezoelectric effect, during the deformation of the C-shaped piezoelectric cantilever beam 7, the PZT on the piezoelectric vibrator is squeezed, and a certain potential difference will be generated on its upper and lower surfaces, and then electric energy is output, realizing the conversion of wave energy into electric energy.

[0043] In summary, in this embodiment, the rotation of the pendulum 5 enables the collection device to respond to wave excitations in multiple directions, can capture wave energy in multiple directions, and realizes the collection of wave energy in multiple directions. Moreover, a plurality of first magnets 4 are installed on the turntable 3, so that when the turntable 3 rotates one circle, the C-shaped piezoelectric cantilever beam 7 can be plucked multiple times, further enhancing the effect of frequency up-conversion conversion. In addition, the non-linear stiffness characteristic of the C-shaped piezoelectric cantilever beam 7 and the dynamic matching of the pendulum 5 excitation significantly broaden the effective working frequency band of the system. At the same time, compared with the traditional cantilever beam, the inherent frequency of the C-shaped piezoelectric cantilever beam 7 structure is significantly reduced, and it is easier to generate large-amplitude deformation under ultra-low-frequency wave excitation.

[0044] In addition, arranging the magnetic poles of adjacent first magnets 4 in the opposite direction can increase the change range of the magnetic force. Under the plucking of the alternating magnetic poles, the C-shaped piezoelectric cantilever beam 7 can generate large-amplitude deformation, thereby enhancing its electric energy output effect.

[0045] In this embodiment Figure 5 For the influence of different magnetic pole arrangement methods on the magnetic force received by the square magnet, when the magnetic poles are arranged in the same direction, the magnetic force change range is from -236.9 mN to 236.9 mN, and when the adjacent magnetic poles are arranged in the reverse direction, the magnetic force change range is from -731.7 mN to 244.8 mN. This means that when the adjacent magnetic poles are arranged in the reverse direction, the magnetic force received by the C-shaped piezoelectric cantilever beam 7 can be enhanced, so that the PZT generates a greater strain. The strain of the PZT is proportional to its voltage output. The enhancement of the magnetic force can improve its electric energy output. In addition, a larger range of magnetic force changes can also enable the C-shaped piezoelectric cantilever beam 7 to obtain a better plucking effect.

[0046] Figure 6It is an experimental data graph of the influence of different magnetic pole arrangements on the voltage output of the acquisition device when the wave frequency is 0 - 1 Hz. In the test, it can be found that the output voltage of the device first rises and then falls with the increase of the wave frequency, and the voltage output is optimal when the wave frequency is 0.8 Hz. By comparing the voltage outputs under different magnetic pole arrangements, it can be found that the voltage output when adjacent magnetic poles are arranged in the opposite direction is significantly higher than that when the magnetic poles are arranged in the same direction, and the maximum peak-to-peak voltage is increased by 38%. Under the optimal parameters, the voltage output range of the device is 82.2 V - 140.2 V. This shows that the device has good broadband performance under ultra-low frequency (less than 1 Hz) excitation, and even when the wave frequency is 0.1 Hz, the peak-to-peak voltage output can reach 82.2 V.

[0047] Figure 7 It is an experimental data graph of the power output of the acquisition device under different external impedances. The actual output power of the acquisition device can be measured by measuring the voltage across its two ends in parallel with an adjustable resistor and then calculated according to the formula U2 / R = P. We tested the power output of the device under different external impedances at 0.8 Hz, and the test results are as Figure 7 shown. When the impedance is 15 kΩ, the optimal power output of the device is 58.89 mW. The power output of this acquisition device can meet the power supply requirements of some microelectronic devices at the mW level.

[0048] In order to verify the feasibility of powering microelectronic devices by this device in a water wave environment, we conducted an actual power supply test in a wave tank. Figure 8 It shows the voltage curve of the acquisition device powering two thermohygrometers with a rated voltage of 1.5 V at the same time. The results show that when a 1 mF capacitor is connected in parallel, the voltage rises to 4 V after 210 s of power supply. When the switch is closed, the capacitor starts to discharge, and at this time, the thermohygrometer displays a digital pattern. After 130 s of discharge, the voltage stabilizes at 1.28 V, and the thermohygrometer can keep running stably in this state. Figure 9 It is the power supply circuit of the thermohygrometer and the state when the thermohygrometer runs stably. The above test results show that this acquisition device has the ability to power microelectronic devices in a marine environment.

[0049] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention, and any reference signs in the claims should not be regarded as limiting the claims involved.

[0050] The above-described embodiments merely represent the implementation modes of the invention. The protection scope of the present invention is not limited to the above embodiments. For those skilled in the art, without departing from the concept of the present invention, several variations and improvements can be made, and these all fall within the protection scope of the present invention.

Claims

1. A piezoelectric wave energy collection device based on a C-shaped cantilever beam, characterized in that: The invention comprises a shell, a fixed shaft, a turntable, a first magnet, a pendulum, a C-shaped piezoelectric cantilever beam and a second magnet. The fixed shaft is vertically fixed inside the sealed shell. The turntable is coaxially arranged on the fixed shaft so as to be rotatable. A plurality of first magnets are evenly arranged on the turntable along its circumferential direction. The magnetic poles of adjacent first magnets are opposite. The pendulum is arranged on the turntable. A plurality of groups of C-shaped piezoelectric cantilever beams are evenly arranged on the fixed shaft along its circumferential direction. One end of the C-shaped piezoelectric cantilever beam is arranged on the fixed shaft, and the other end is arranged below the first magnet. The second magnet is arranged at the end of the C-shaped piezoelectric cantilever beam arranged below the first magnet.

2. A piezoelectric wave energy collection device based on a C-shaped cantilever beam according to claim 1, characterized in that: The turntable includes a turntable body and a fixed column. A plurality of first magnets are evenly arranged along the circumferential direction of the turntable body. A fixed column is arranged at the center of the turntable body. A rotating through hole through which a fixed shaft can pass is provided at the center of the turntable body and the fixed column. Bearings for mounting the fixed shaft are arranged at both the upper and lower ends of the rotating through hole. One end of the pendulum is arranged on the fixed column. The swing of the pendulum drives the turntable to rotate on the fixed shaft.

3. A piezoelectric wave energy collection device based on a C-shaped cantilever beam according to claim 2, characterized in that: A boss is arranged on the outer wall of the fixed column, and a slot hole matching the horizontal cross-section shape of the fixed column is arranged at one end of the pendulum, so that the swing of the pendulum can drive the turntable body to rotate on the fixed axis.

4. A piezoelectric wave energy collection device based on a C-shaped cantilever beam according to claim 2, characterized in that: The turntable body is evenly provided with mounting through holes corresponding to the number of the first magnets along its circumferential direction, a first magnet is installed in each mounting through hole, and the heights of adjacent first magnets are staggered.

5. The piezoelectric wave energy collection device based on a C-shaped cantilever beam according to claim 2, characterized in that: Six first magnets are evenly arranged on the turntable body along its circumferential direction.

6. The piezoelectric wave energy collection device based on a C-shaped cantilever beam according to claim 1, characterized in that: The first magnet is a cylindrical magnet.

7. The piezoelectric wave energy collection device based on a C-shaped cantilever beam according to claim 1, characterized in that: The pendulum is a 120° fan-shaped block structure.

8. The piezoelectric wave energy collection device based on a C-shaped cantilever beam according to claim 1, characterized in that: A support seat is also provided on the top of the fixed shaft, and one end of the C-shaped piezoelectric cantilever beam is fixedly connected to the support seat.

9. The piezoelectric wave energy collection device based on a C-shaped cantilever beam according to claim 1, characterized in that: The C-shaped piezoelectric cantilever beam includes an upper piezoelectric vibrator, a middle piezoelectric vibrator, a lower piezoelectric vibrator and a connecting block. The two ends of the middle piezoelectric vibrator are respectively connected to the upper piezoelectric vibrator and the lower piezoelectric vibrator through the connecting blocks, the end of the upper piezoelectric vibrator away from the middle piezoelectric vibrator is connected to the fixed axis, and the second magnet is arranged at the end of the lower piezoelectric vibrator away from the middle piezoelectric vibrator.

10. The piezoelectric wave energy collection device based on a C-shaped cantilever beam according to claim 1, characterized in that: The number of the C-shaped piezoelectric cantilever beams is 3 groups.

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