Multidirectional piezoelectric vibration energy harvester

Abstract

The invention discloses a multidirectional piezoelectric vibration energy harvester, which comprises a lower base, a screw rod, a bent beam, a piezoelectric plate, an upper base, a vibration plate, a permanent magnet and a spiral spring, a spiral spring and a plurality of bent beams are connected between the vibrating plate and the lower base, the bent beams are circumferentially arranged on the edge of the vibrating plate at equal intervals in an array mode, and piezoelectric patches are symmetrically pasted on the upper outer surface and the lower outer surface of each bent beam. When vibration is generated in the environment, received multi-direction excitation is transmitted to the piezoelectric plate of the bending beam, the piezoelectric plate converts collected mechanical vibration energy into electric energy, and collection of vibration energy in different directions is achieved; the square permanent magnets are fixed to the center of the upper surface of the vibrating plate and the center of the lower surface of the adjustable upper base respectively, the magnets are placed in the same polarity, the inherent frequency of the energy harvester can be changed by adjusting the distance between the upper base and the vibrating plate and changing the magnitude of magnetic repulsive force in allusion to different external environments, and the energy harvester can resonate with the environment more easily, so that the energy harvester is more stable in performance. Therefore, the electric energy capturing efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of renewable energy power generation, and in particular relates to a multi-directional piezoelectric vibration energy harvester. Background Art

[0002] In recent years, with the rapid development of micro-electromechanical systems, wireless sensors, MEMS components, micro-robots and smart wearable devices are all moving towards miniaturization and low energy consumption, while traditional energy supply methods have become one of the main problems hindering the development of micro-devices. Traditional chemical batteries have the disadvantages of small energy storage, short service life and the need for manual replacement, which makes it difficult to meet the actual working needs of micro-electronic devices. Therefore, solving the energy supply problem of micro-electronic devices has become an urgent problem that needs to be solved.

[0003] There are many forms of green energy in the environment, such as wind energy, vibration energy, solar energy and tidal energy. Among them, vibration energy has the advantages of being relatively stable, widely available, high in energy density and easy to obtain. With the development of science and technology, it has become possible to use energy harvesting devices to collect vibration energy in the environment to power microelectronic devices, and it also has a good development prospect.

[0004] At present, there are three main ways to harvest vibration energy: electrostatic, electromagnetic, and piezoelectric. In order to harvest vibration energy in the environment, piezoelectric energy harvesters have been widely studied by researchers at home and abroad. Traditional piezoelectric vibration energy harvesters have a narrow energy harvesting band, and once the environmental vibration changes, the energy harvesting efficiency will be greatly reduced, which cannot guarantee the energy supply requirements of microelectronic devices, thus affecting the normal operation of electronic devices. Summary of the invention

[0005] The present invention provides a multi-directional piezoelectric vibration energy harvester, which can solve the problem that the traditional piezoelectric vibration energy harvester can only harvest energy in a specific frequency band and a specific direction.

[0006] To solve the above problems, the technical solution provided by the present invention is as follows: An embodiment of the present invention provides a multi-directional piezoelectric vibration energy harvester, comprising a lower base (1) and an upper base (7), wherein a plurality of screws (2) are connected between the edge of the lower base (1) and the edge of the upper base (7), and the plurality of screws (2) and the upper base (7) are fixed via nuts (6); a vibration plate (8) is further arranged between the lower base (1) and the upper base (7), a first permanent magnet (5-1) is arranged at the bottom of the upper base (7), and a second permanent magnet (5-2) is arranged on the side of the vibration plate (8) facing the first permanent magnet (5-1); A spiral spring (9) and a plurality of bent beams (3) are connected between the vibration plate (8) and the lower base (1), and the plurality of bent beams (3) are arranged in a circular array at equal intervals on the edge of the vibration plate (8), and a piezoelectric sheet (4) is symmetrically attached to the upper outer surface and the lower outer surface of each bent beam (3); when vibration is generated in the environment, the received multi-directional excitation is transmitted to the piezoelectric sheet (4) of the bent beam (3), and the piezoelectric sheet (4) converts the collected mechanical vibration energy into electrical energy, thereby realizing the collection of vibration energy in different directions; when dealing with different external environments, the distance between the upper base (7) and the vibration plate (8) can be adjusted to change the magnitude of the magnetic repulsion force, thereby changing the natural frequency of the energy harvester, making it easier to resonate with the environment, thereby increasing the efficiency of capturing electrical energy.

[0007] In an optional embodiment of the present invention, the upper outer surface and the lower outer surface of the bending beam (3) are both wedge-shaped structures, and the upper outer surface and the lower outer surface of the bending beam (3) gradually narrow near the bending section.

[0008] In an optional embodiment of the present invention, a first boss (10-1) is provided on the lower base (1), a second boss (10-2) is provided on the vibration plate (8) facing the first boss (10-1), and two ends of the spiral spring (9) are nested on the first boss (10-1) and the second boss (10-2).

[0009] In an optional embodiment of the present invention, the bottoms of the plurality of bent beams (3) are detachably connected to the lower base (1) via bolts, and the resonant frequency of the energy harvester can be adjusted by replacing the lower base (1) with different thicknesses.

[0010] In an optional embodiment of the present invention, the upper base (7) realizes a detachable connection and a distance adjustment function through a screw rod (2) and a nut (6), and the magnetic force is changed by changing the distance between the upper base (7) and the vibration plate (8), thereby adjusting the resonant frequency of the energy harvester.

[0011] In an optional embodiment of the present invention, the lower base (1), the upper base (7) and the vibration plate (8) are all circular structures with a preset thickness, and the central axes of the lower base (1), the upper base (7), the vibration plate (8) and the spiral spring (9) are coaxially arranged.

[0012] In an optional embodiment of the present invention, the piezoelectric sheet (4) is made of PZT-5H piezoelectric ceramic, polarized in the vertical direction, and has an electrode layer plated on the surface.

[0013] Compared with the prior art, the embodiment of the present invention provides a multi-directional piezoelectric vibration energy harvester, which has the following beneficial effects: (1) The technical solution of the present invention solves the problem that multi-directional and wide frequency band cannot be taken into account in the past, and efficiently utilizes space without being restricted by the use scene. (2) The unique design of the bent beam structure adopted by the present invention can effectively reduce the resonance frequency of each order of the energy harvesting device, expand the working frequency band, and reduce the influence of the change of the environmental vibration source on the energy harvesting efficiency; at the same time, for different vibration sources, the resonance frequency of the device can be changed by adjusting the distance between the upper base and the vibration plate, and the upper and lower bases of the energy harvester will not be deformed, thereby improving the stability of the energy harvester. (3) When the energy harvester of the present invention receives external excitation, the lower base transmits the vibration to the vibration plate through the bent beam and the spiral spring respectively, and the permanent magnet on the vibration plate vibrates accordingly, thereby affecting the magnitude of the magnetic repulsion force, thereby affecting the vibration of the bent piezoelectric beam, widening the energy harvesting frequency band, and improving the energy harvesting efficiency. (4) The present invention has the advantages of compact structure, high space utilization efficiency, low cost, no external interference, green and pollution-free, etc., and can meet the requirements of integration and miniaturization to a certain extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0015] Figure 1 A schematic diagram of the structure of a multi-directional piezoelectric vibration energy harvester provided in an embodiment of the present application. DETAILED DESCRIPTION

[0016] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0017] like Figure 1 As shown, an embodiment of the present invention provides a multi-directional piezoelectric vibration energy harvester, including a lower base 1 and an upper base 7, multiple screws 2 are connected between the edge of the lower base 1 and the edge of the upper base 7, and the multiple screws 2 and the upper base 7 are fixed by nuts 6. The upper base 7 can achieve a distance adjustment function through the screws 2 and the nuts 6. The installation points of the multiple screws 2 between the upper base 7 and the lower base 1 are located at the periphery of the two bases, and the installation points are symmetrically arranged around the center of the base circle.

[0018] A vibration plate 8 is also provided between the lower base 1 and the upper base 7, and the vibration plate 8 can freely move in any direction in response to vibrations in the environment. A first permanent magnet 5-1 is provided at the bottom of the upper base 7; a second permanent magnet 5-2 is provided on the side of the vibration plate 8 facing the first permanent magnet 5-1; the first permanent magnet 5-1 and the second permanent magnet 5-2 are two magnets of the same polarity, which repel each other and generate a certain magnetic repulsion. In this embodiment, the first permanent magnet 5-1 and the second permanent magnet 5-2 are preferably square permanent magnets, and the magnets are placed with the same polarity.

[0019] A spiral spring 9 and a plurality of bending beams 3 are connected between the vibration plate 8 and the lower base 1. The plurality of bending beams 3 have a preset elasticity and can be bent and deformed in a self-restoring manner. In this embodiment, the plurality of bending beams 3 are arranged in a circular array with equal spacing on the edge of the vibration plate 8. The upper and lower outer surfaces of each bending beam 3 are symmetrically attached with piezoelectric sheets 4; the piezoelectric sheets 4 are made of PZT-5H piezoelectric ceramics, polarized in the vertical direction, and coated with an electrode layer on the surface.

[0020] When vibration occurs in the environment, the received multi-directional excitation is transmitted to the piezoelectric sheet 4 of the bending beam 3, and the piezoelectric sheet 4 converts the collected mechanical vibration energy into electrical energy to realize the collection of vibration energy in different directions; when facing different external environments, the distance between the upper base 7 and the vibration plate 8 can be adjusted to change the magnitude of the magnetic repulsion force, thereby changing the natural frequency of the energy harvester, making it easier to resonate with the environment to increase the efficiency of capturing electrical energy. The environment where the multi-directional piezoelectric vibration energy harvester in this embodiment is placed has green energy such as wind energy, vibration energy, solar energy and tidal energy, among which vibration energy has the advantages of being relatively stable, having a high energy density and being easy to obtain, which is conducive to the energy harvester generating the required electrical energy.

[0021] The axis of the coil spring 9 is perpendicular to the end faces of the lower base 1 and the vibration plate 8, and the inner surface of the coil spring 9 is matched with the outer surface of the bosses of the lower base 1 and the vibration plate 8. For example, a first boss 10-1 is provided on the lower base 1, and a second boss 10-2 is provided on the vibration plate 8 facing the first boss 10-1, and both ends of the coil spring 9 are nested on the first boss 10-1 and the second boss 10-2.

[0022] The upper and lower outer surfaces of the bending beam 3 are both wedge-shaped, and the upper and lower outer surfaces of the bending beam 3 gradually narrow near the bending section, that is, the cross-section is wide at both ends of the bending beam 3 and narrowest in the middle. The bottoms of the multiple bending beams 3 are detachably connected to the lower base 1 by bolts, and the resonant frequency of the energy harvester can be adjusted by replacing the lower bases 1 of different thicknesses. The upper base 1 is detachably connected and has a distance adjustment function through the screw 2 and the nut 6. The magnetic force can be changed by changing the distance between the upper base 1 and the vibration plate 8, thereby adjusting the resonant frequency of the device.

[0023] The lower base 1, the upper base 7 and the vibration plate 8 in this embodiment are all circular structures with a preset thickness, and the central axes of the lower base 1, the upper base 7, the vibration plate 8 and the spiral spring 9 are coaxially arranged. The upper base 1 realizes a detachable connection and a distance adjustment function through a screw rod 2 and a nut 6, and the resonant frequency of the device can be adjusted by changing the distance between the upper base 1 and the vibration plate 8.

[0024] In summary, although the present invention has been disclosed as above in terms of preferred embodiments, the above preferred embodiments are not intended to limit the present invention. A person skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope defined in the claims.

Claims

1. A multi-directional piezoelectric vibration energy harvester, characterized in that: The invention comprises a lower base (1) and an upper base (7), wherein a plurality of screws (2) are connected between the edge of the lower base (1) and the edge of the upper base (7), and the plurality of screws (2) and the upper base (7) are fixed via nuts (6); a vibration plate (8) is also arranged between the lower base (1) and the upper base (7), a first permanent magnet (5-1) is arranged at the bottom of the upper base (7), and a second permanent magnet (5-2) is arranged on the side of the vibration plate (8) facing the first permanent magnet (5-1); A spiral spring (9) and a plurality of bent beams (3) are connected between the vibration plate (8) and the lower base (1), and the plurality of bent beams (3) are arranged in a circular array at equal intervals on the edge of the vibration plate (8), and a piezoelectric sheet (4) is symmetrically attached to the upper outer surface and the lower outer surface of each bent beam (3); when vibration is generated in the environment, the received multi-directional excitation is transmitted to the piezoelectric sheet (4) of the bent beam (3), and the piezoelectric sheet (4) converts the collected mechanical vibration energy into electrical energy, thereby realizing the collection of vibration energy in different directions; when dealing with different external environments, the distance between the upper base (7) and the vibration plate (8) can be adjusted to change the natural frequency of the energy harvester, making it easier to resonate with the environment, thereby increasing the efficiency of capturing electrical energy.

2. A multi-directional piezoelectric vibration energy harvester according to claim 1, characterized in that: The upper outer surface and the lower outer surface of the bending beam (3) are both wedge-shaped structures, and the upper outer surface and the lower outer surface of the bending beam (3) gradually become narrower near the bending section.

3. The multi-directional piezoelectric vibration energy harvester according to claim 1, characterized in that: A first boss (10-1) is arranged on the lower base (1), a second boss (10-2) is arranged on the vibration plate (8) facing the first boss (10-1), and two ends of the spiral spring (9) are nested on the first boss (10-1) and the second boss (10-2).

4. The multi-directional piezoelectric vibration energy harvester according to claim 3, characterized in that: The bottoms of the multiple bent beams (3) are detachably connected to the lower base (1) via bolts, and the resonant frequency of the energy harvester can be adjusted by replacing the lower base (1) with different thicknesses.

5. The multi-directional piezoelectric vibration energy harvester according to claim 4, characterized in that: The upper base (7) realizes detachable connection and distance adjustment functions through a screw rod (2) and a nut (6), and the magnetic force is changed by changing the distance between the upper base (7) and the vibration plate (8), thereby adjusting the resonant frequency of the energy harvester.

6. The multi-directional piezoelectric vibration energy harvester according to claim 5, characterized in that: The lower base (1), the upper base (7) and the vibration plate (8) are all circular structures with a preset thickness, and the central axes of the lower base (1), the upper base (7), the vibration plate (8) and the spiral spring (9) are coaxially arranged.

7. The multi-directional piezoelectric vibration energy harvester according to claim 1, characterized in that: The piezoelectric sheet (4) is made of PZT-5H piezoelectric ceramic, polarized in the vertical direction, and has an electrode layer plated on the surface.

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