Omnidirectional energy collector based on piezoelectric effect and adjusting method thereof

Abstract

The invention discloses an omnidirectional energy collector based on a piezoelectric effect and an adjusting method thereof, and belongs to the technical field of energy collectors. According to the invention, omnidirectional energy collection can be realized, and the complex structure caused by arraying unidirectional collectors along different directions and the difficulty brought by signal processing are avoided; under the action of the mass block and the support slender rod, the bending deformation of the piezoelectric plate is greater than the deformation generated by only placing the side plate, and meanwhile, the defect of low torsional deformation voltage signal is avoided; the inherent frequency of the structure can be changed through the mass and the height of the mass block, resonance with the excitation frequency is achieved, bending deformation of the piezoelectric plate is increased, and therefore piezoelectric voltage output is improved. Due to the fact that the side plates have certain elasticity, when the mass block swings back, the side plates swing back, the structure that the side plates are arranged up and down is adopted, and motion interference generated when the side plates swing back can be effectively avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of energy harvesters, and in particular to an omnidirectional energy harvester based on piezoelectric effect and an adjustment method thereof. Background Art

[0002] Most of the existing energy harvesters can only perform unidirectional energy harvesting and cannot be used in multiple scenarios, so their usage scenarios are limited. Some energy harvesters can achieve multi-directional energy harvesting (Kan Junwu, Wu Yaqi, Zhang Zhonghua, et al. Research on torsion pendulum multi-directional piezoelectric vibration energy harvester [J]. China Mechanical Engineering, 2023, 34(4): 440-445. DOI: 10.3969 / j.issn.1004-132X.2023.04.008.), but some directions are distortion deformation of thin plates, and the harvesting efficiency is low. In order to improve the efficiency of low-frequency vibration energy harvesting, some experts and scholars have arranged unidirectional energy harvesting in an array to achieve multi-directional energy harvesting. However, this form of structure is relatively complex, which limits the application of energy harvesters in the field of self-powered sensors.

[0003] How to achieve omnidirectional energy harvesting while reducing the complexity of the structure is an urgent problem to be solved. To this end, an omnidirectional energy harvester based on piezoelectric effect and its adjustment method are proposed. Summary of the invention

[0004] The technical problem to be solved by the present invention is: how to achieve omnidirectional energy harvesting under the condition of reducing structural complexity, and to provide an omnidirectional energy harvester based on the piezoelectric effect.

[0005] The present invention solves the above technical problems through the following technical solutions. The present invention includes a swing mechanism, a substrate, a supporting beam and four side plates. The lower end of the swing mechanism is arranged at the middle position of the upper surface of the substrate. When the substrate is vibrated, the vibration displacement signal is amplified by the swing mechanism. The lower end of the supporting beam is fixedly connected to the substrate. The four side plates include two upper side plates and two lower side plates, wherein the upper ends of the two upper side plates are fixedly connected to the supporting beam, and the lower ends of the two lower side plates are fixedly connected to the substrate. The lower parts of the two upper side plates and the upper parts of the two lower side plates are arranged on the outside of the swing mechanism and are in contact with the outside of the swing mechanism. A piezoelectric sheet is arranged on the upper part of the outer surface of the two upper side plates, and a piezoelectric sheet is arranged on the lower part of the outer surface of the two lower side plates.

[0006] Furthermore, the swing mechanism includes a thin supporting rod and a mass block, wherein the mass block is arranged at the upper end of the thin supporting rod and is detachably connected thereto, and the thin supporting rod is arranged perpendicular to the base plate, and the lower end thereof is fixedly connected to the base plate.

[0007] Furthermore, the mass block and the supporting thin rod are connected by threads.

[0008] Furthermore, the lower parts of the two upper side plates and the upper parts of the two lower side plates are arranged around the outer side of the mass block and are in contact with the outer side of the mass block. The lower end surfaces of the two upper side plates are flush with the upper end surfaces of the two lower side plates.

[0009] Furthermore, the four side panels have the same specifications and are all arranged perpendicular to the base plate.

[0010] Furthermore, the two upper side plates are parallel to each other, and the two lower side plates are parallel to each other.

[0011] Furthermore, mounting holes for mounting the energy harvester are arranged at the four corners of the substrate.

[0012] The present invention also provides a method for adjusting the above-mentioned omnidirectional energy harvester based on piezoelectric effect, which is used to adjust the resonant frequency of the swing mechanism so that the resonant frequency is consistent with the vibration frequency, comprising the following steps:

[0013] S1: The frequency of the vibration source is measured by the sensor, that is, the vibration frequency;

[0014] S2: Select the weight and height of the mass block according to the calculation formula;

[0015] S3: According to the weight and height of the selected mass block, the weight and height of the mass block in the energy harvester are adjusted, and then the adjusted energy harvester is placed at the vibration source to harvest energy.

[0016] Furthermore, in step S2, the calculation formula is as follows:

[0017]

[0018] Where f is the resonant frequency of the swing mechanism, Y is the elastic modulus of the supporting thin rod, I is the moment of inertia of the swing mechanism, l b is the length of the supporting rod, l m is the height of the mass block, m is the weight of the mass block, f, Y, I, l b is a known quantity.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] 1. It can realize omnidirectional energy collection, avoiding the complexity of structure and the difficulty of signal processing caused by arranging unidirectional collectors in different directions;

[0021] 2. Through the action of the mass block and the supporting thin rod, the bending deformation of the piezoelectric sheet is greater than the deformation caused by simply placing the side plate, while avoiding the disadvantage of low torsional deformation voltage signal;

[0022] 3. The natural frequency of the structure can be changed by the mass and height of the mass block to achieve resonance with the excitation frequency, increase the bending deformation of the piezoelectric sheet, and thus increase the piezoelectric voltage output;

[0023] 4. Since the side panels have a certain elasticity, when the mass block swings back, the side panels will also swing back. The structure of arranging the side panels up and down can effectively avoid motion interference when the side panels swing back. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a schematic diagram of the overall structure of an omnidirectional energy harvester based on piezoelectric effect in an embodiment of the present invention;

[0025] Figure 2 It is a side structural schematic diagram (right side) of an omnidirectional energy harvester based on piezoelectric effect in an embodiment of the present invention. DETAILED DESCRIPTION

[0026] The following is a detailed description of an embodiment of the present invention. This embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation method and a specific operation process are given, but the protection scope of the present invention is not limited to the following embodiment.

[0027] like Figure 1 As shown, this embodiment provides a technical solution: an omnidirectional energy harvester based on piezoelectric effect, comprising a swing mechanism, a substrate 7, a supporting beam 1 and four side plates, wherein the lower end of the swing mechanism is arranged at the middle position of the upper surface of the substrate 7, when the substrate 7 is vibrated, the vibration displacement signal is amplified by the swing mechanism, the lower end of the supporting beam 1 is fixedly connected to the substrate 7, the four side plates include two upper side plates 21, 22 and two lower side plates 41, 42, wherein the upper ends of the two upper side plates 21, 22 are fixedly connected to the supporting beam 1, the lower ends of the two lower side plates 41, 42 are fixedly connected to the substrate 7, the lower parts of the two upper side plates 21, 22 and the upper parts of the two lower side plates 41, 42 are arranged on the outside of the swing mechanism and are in contact with the outside of the swing mechanism, a piezoelectric sheet 6 is arranged on the upper part of the outer surface of the two upper side plates 21, 22, and a piezoelectric sheet 6 is arranged on the lower part of the outer surface of the two lower side plates 41, 42.

[0028] In this embodiment, the swing mechanism includes a thin support rod 5 and a mass block 3, wherein the mass block 3 is arranged at the upper end of the thin support rod 5 and is detachably connected thereto, and the thin support rod 5 is arranged perpendicular to the substrate 7, and its lower end is fixedly connected to the substrate 7. The detachable connection makes it convenient to replace mass blocks 1 of different specifications, thereby facilitating the adjustment of the resonant frequency of the swing mechanism.

[0029] In this embodiment, the mass block 3 and the supporting thin rod 5 are connected by threads.

[0030] In this embodiment, the lower parts of the two upper side plates 21, 22 and the upper parts of the two lower side plates 41, 42 are arranged around the outer side of the mass block 3 and are in contact with the outer side of the pendulum mass block 3 on all sides. The lower end surfaces of the two upper side plates 21, 22 are higher than and flush with the upper end surfaces of the two lower side plates 41, 42.

[0031] In this embodiment, the four side panels have the same specifications and are all arranged perpendicular to the base plate 7 .

[0032] In this embodiment, the two upper side plates 21 and 22 are parallel to each other, and the two lower side plates 41 and 42 are parallel to each other.

[0033] In this embodiment, mounting holes 71 are provided at the four corners of the substrate 7 for mounting the energy harvester.

[0034] In this embodiment, the side plate is a rectangular plate, the base plate 10 is a square plate, and the mass block 1 is a cube with a connection hole.

[0035] The following is an example of the working process of the energy harvester:

[0036] When the substrate 7 is subjected to vibration along the positive direction of the x-axis, the swing mechanism composed of the supporting thin rod 5 and the mass block 3 will swing back and forth along the x-axis direction, and this swing mechanism can amplify the vibration displacement signal. In the process of the mass block 3 swinging back and forth along the x-axis direction, the lower side plate 41 and the lower side plate 42 are squeezed back and forth to bend and deform, thereby causing the piezoelectric sheet 6 to generate voltage.

[0037] When the supporting thin rod 5 and the mass block 3 swing in the positive direction of the x-axis, the mass block 3 squeezes the lower side plate 41, causing the lower side plate 41 to bend and deform, driving the piezoelectric sheet 6 at the lower part of the outer surface of the lower side plate 41 to deform and generate a voltage signal. During the swing back, the mass block 3 squeezes the lower side plate 42, causing the piezoelectric sheet 6 at the lower part of the outer surface of the lower side plate 42 to bend and deform and generate a voltage signal. Such reciprocating motion causes the piezoelectric sheet 6 to generate a continuous voltage signal, which can power the self-powered sensor.

[0038] When the substrate 7 is subjected to vibration in the negative direction of the y-axis, the swing mechanism composed of the supporting thin rod 5 and the mass block 3 will swing back and forth along the y-axis, and the swing mechanism can amplify the vibration displacement signal. In the process of the mass block 3 swinging back and forth along the y-axis, the upper side plate 21 and the upper side plate 22 are squeezed back and forth to bend and deform, thereby causing the piezoelectric sheet 6 to generate voltage.

[0039] When the supporting thin rod 5 and the mass block 3 swing in the negative direction of the y-axis, the mass block 3 squeezes the upper side plate 21, causing the upper side plate 21 to bend and deform, driving the piezoelectric sheet 6 on the upper surface of the upper side plate 21 to deform and generate a voltage signal. During the swing back, the mass block 3 squeezes the upper side plate 22, causing the piezoelectric sheet 6 on the upper surface of the upper side plate 22 to bend and deform and generate a voltage signal. Such reciprocating motion causes the piezoelectric sheet 6 to generate a continuous voltage signal, which can power the self-powered sensor.

[0040] When the substrate 7 is subjected to vibration at a certain angle to the positive direction of the x-axis, the mass block 3 will squeeze the upper and lower side plates. Take the vibration at an angle of 30° to the positive direction of the x-axis as an example. When the excitation direction is at an angle of 30° to the positive direction of the x-axis, the swing mechanism composed of the supporting thin rod 5 and the mass block 3 swings back and forth in the direction at an angle of 30° to the positive direction of the x-axis. The mass block 3 will squeeze the upper side plate 22 and the lower side plate 41, causing the upper side plate 22 and the lower side plate 41 to bend and deform, driving the piezoelectric sheet 6 on its outer surface to deform and generate a voltage signal. During the swing back process, the mass block 3 squeezes the upper side plate 21 and the lower side plate 42, causing the piezoelectric sheet 6 on its outer surface to bend and deform, generating a voltage signal. Such reciprocating motion causes the piezoelectric sheet 6 to generate a continuous voltage signal, which can power the self-powered sensor.

[0041] It should be noted that, since the side panels have a certain elasticity, when the mass block 3 swings back, the side panels will also swing back. This structure adopts a structure in which the side panels are arranged up and down, which can effectively avoid motion interference when the side panels swing back.

[0042] This embodiment also provides a method for adjusting the above-mentioned omnidirectional energy harvester based on piezoelectric effect, which is specifically described as follows:

[0043] When the vibration signal is very weak, in order to amplify and effectively collect the voltage signal, the mass and height of the mass block can be adjusted to adjust the resonant frequency of the swing mechanism composed of the supporting thin rod and the mass block, so that its frequency is consistent with the vibration frequency to achieve a resonance effect, increase the bending deformation of the side plate, and achieve amplification of the voltage signal.

[0044] The specific adjustment process is as follows:

[0045] Step 1: Measure the frequency of the vibration source, i.e., the vibration frequency, through the sensor;

[0046] Step 2: Select the weight and height of the mass block according to the calculation formula. The calculation formula is as follows:

[0047]

[0048] Where f is the resonant frequency of the swing mechanism, Y is the elastic modulus of the supporting thin rod, I is the moment of inertia of the swing mechanism, l bis the length of the supporting rod, l m is the height of the mass block, m is the weight of the mass block, f, Y, I, l b is a known quantity.

[0049] It should be noted that according to the above formula, the height l of the mass block can be solved m , the solution set of the mass block weight m, the designer can choose a reasonable solution according to the actual situation to determine the height l of the mass block m , the specific size of the weight m of the mass block.

[0050] When the mass block is a sphere, the height l of the mass block m is the diameter of the sphere; when the mass block is a cuboid (its upper and lower surfaces are squares), the side edge height of the cuboid is the height l of the mass block m .

[0051] Step 3: According to the calculated weight and height of the mass block, adjust the weight and height of the mass block in the energy harvester, and then place the adjusted energy harvester at the vibration source to harvest energy.

[0052] In this embodiment, if the length of the supporting thin rod is adjusted, the height of the supporting beam 1 also needs to be adjusted, which increases the design difficulty. The purpose of adjusting the frequency can also be achieved by adjusting only the mass and height of the mass block.

[0053] In summary, the omnidirectional energy harvester based on piezoelectric effect and the adjustment method thereof of the above-mentioned embodiments can realize omnidirectional energy harvesting, avoiding the structural complexity and signal processing difficulties caused by arranging unidirectional harvesters in different directions; through the action of the mass block and the supporting thin rod, the bending deformation of the piezoelectric sheet is larger than the deformation caused by simply placing the side plate, while avoiding the disadvantage of low torsional deformation voltage signal; the natural frequency of the structure can be changed by the mass and height of the mass block to achieve resonance with the excitation frequency, increase the bending deformation of the piezoelectric sheet, and thus improve the piezoelectric voltage output; because the side plates have a certain elasticity, when the mass block swings back, the side plates will also swing back, and the structure of arranging the side plates up and down can effectively avoid motion interference when the side plates swing back.

[0054] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. An omnidirectional energy harvester based on piezoelectric effect, characterized in that: It includes a swing mechanism, a base plate, a supporting beam and four side plates, wherein the lower end of the swing mechanism is arranged at the middle position of the upper surface of the base plate. When the base plate vibrates, the vibration displacement signal is amplified by the swing mechanism, the lower end of the supporting beam is fixedly connected to the base plate, and the four side plates include two upper side plates and two lower side plates, wherein the upper ends of the two upper side plates are fixedly connected to the supporting beam, and the lower ends of the two lower side plates are fixedly connected to the base plate, the lower parts of the two upper side plates and the upper parts of the two lower side plates are arranged around the outer side of the swing mechanism and are in contact with the outer side of the swing mechanism, and a piezoelectric sheet is arranged on the upper part of the outer surface of the two upper side plates, and a piezoelectric sheet is arranged on the lower part of the outer surface of the two lower side plates.

2. The omnidirectional energy harvester based on piezoelectric effect according to claim 1, characterized in that: The swing mechanism includes a thin supporting rod and a mass block. The mass block is arranged at the upper end of the thin supporting rod and is detachably connected thereto. The thin supporting rod is arranged perpendicular to the base plate, and the lower end thereof is fixedly connected to the base plate.

3. The omnidirectional energy harvester based on piezoelectric effect according to claim 2, characterized in that: The mass block and the supporting thin rod are connected by threads.

4. The omnidirectional energy harvester based on piezoelectric effect according to claim 2, characterized in that: The lower parts of the two upper side plates and the upper parts of the two lower side plates are arranged around the outer side of the mass block and are in contact with the outer side of the mass block. The lower end surfaces of the two upper side plates are flush with the upper end surfaces of the two lower side plates.

5. The omnidirectional energy harvester based on piezoelectric effect according to claim 4, characterized in that: The four side panels have the same specifications and are all arranged vertically to the base plate.

6. The omnidirectional energy harvester based on piezoelectric effect according to claim 5, characterized in that: The two upper side plates are parallel to each other, and the two lower side plates are parallel to each other.

7. The omnidirectional energy harvester based on piezoelectric effect according to claim 6, characterized in that: The four corners of the substrate are all provided with mounting holes for mounting the energy collector.

8. A method for adjusting an omnidirectional energy harvester based on piezoelectric effect, characterized in that: Used to adjust the resonant frequency of the oscillating mechanism in the energy harvester according to any one of claims 2 to 7 so that the resonant frequency is consistent with the vibration frequency, The following steps are involved: S1: The frequency of the vibration source is measured by the sensor, that is, the vibration frequency; S2: Select the weight and height of the mass block according to the calculation formula; S3: According to the weight and height of the selected mass block, the weight and height of the mass block in the energy harvester are adjusted, and then the adjusted energy harvester is placed at the vibration source to harvest energy.

9. The method for adjusting an omnidirectional energy harvester based on piezoelectric effect according to claim 8, characterized in that: In step S2, the calculation formula is as follows: Where f is the resonant frequency of the swing mechanism, Y is the elastic modulus of the supporting thin rod, I is the moment of inertia of the swing mechanism, l b is the length of the supporting rod, l m is the height of the mass block, m is the weight of the mass block, f, Y, I, l b is a known quantity.

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