Electromagnetic-piezoelectric-friction composite energy harvester

Abstract

This invention provides an electromagnetic-piezoelectric-friction composite energy harvester, aiming to solve the technical problem that existing energy harvesters cannot efficiently harvest low-frequency vibration energy. The mounting frame of this application has a mounting groove at one end. A guide rail is provided at the top of the mounting frame. A coil is mounted on the side of the guide rail away from the mounting groove. The top of the permanent magnet assembly is slidably connected to the guide rail. One end of the spring assembly is mounted on one side of the permanent magnet assembly. A piezoelectric beam, not parallel to the extension direction of the guide rail, is matched and connected to the edge of the mounting groove. The side of the piezoelectric beam facing away from the bottom of the mounting groove is connected to the other end of the spring assembly. A mass block is provided on the side of the piezoelectric beam facing the bottom of the mounting groove. The piezoelectric beam is composed of several plates with a cross structure. Each plate is equipped with piezoelectric ceramic. A fixed magnet and the mass block are mounted opposite each other in the mounting groove. The contact surface materials of the fixed magnet and the mass block are different. This composite energy harvester uses a special piezoelectric beam structure to introduce nonlinear energy exchange, thus broadening the output frequency band.

Description

Technical Field

[0001] This application relates to a composite energy harvester, and more particularly to an electromagnetic-piezoelectric-triboelectric composite energy harvester. Background Technology

[0002] With social development, achieving safe, intelligent, efficient, and green mining and clean, efficient utilization of coal through technological progress is one of the important directions for the high-quality development of my country's coal industry. In recent years, under the guidance of the "National Medium- and Long-Term Science and Technology Development Plan Outline (2006-2020)," which clearly proposed "focusing on the research and development of efficient coal mining technologies and supporting equipment" and "focusing on the research of monitoring, early warning, and prevention technologies for production accidents in coal mines and other mines," the self-powered wireless real-time monitoring of coal mining equipment has undoubtedly become a development trend of smart mines.

[0003] As is well known, traditional power supply methods for equipment have many drawbacks. For example, if battery power is used, the batteries have limited lifespan, are difficult to replace, and are expensive; moreover, used batteries cause environmental pollution. If hydropower or wind power is used, it is mainly suitable for high-power applications, is expensive and bulky, and therefore unsuitable for powering low-power electronic devices. Therefore, emerging power supply technologies such as vibration energy harvesters that convert vibration energy into electrical energy have emerged. This method is unaffected by weather, season, or temperature, and can provide a sufficient energy source for the vibration energy harvester, thus facilitating sufficient self-powering of the equipment.

[0004] However, existing vibration energy harvester structures cannot efficiently collect low-frequency vibration energy, and most harvesters suffer from internal friction and collision energy loss, which affects energy conversion efficiency. Utility Model Content

[0005] The purpose of this invention is to provide an electromagnetic-piezoelectric-triboelectric composite energy harvester to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, this utility model provides the following technical solution:

[0007] An electromagnetic-piezoelectric-triboelectric composite energy harvester includes:

[0008] The mounting bracket has a mounting slot at one end; the top of the mounting bracket has a guide rail; a coil is mounted on the side of the guide rail away from the mounting slot.

[0009] The permanent magnet assembly is slidably connected to the guide rail at the top;

[0010] A spring assembly, one end of which is mounted on one side of the permanent magnet assembly;

[0011] A piezoelectric beam is connected to the edge of the mounting groove, not parallel to the extension direction of the guide rail; the side of the piezoelectric beam facing away from the bottom of the mounting groove is connected to the other end of the spring assembly; a mass block is provided on the side of the piezoelectric beam facing the bottom of the mounting groove; the piezoelectric beam is composed of plates with a cross structure; each plate is provided with piezoelectric ceramic.

[0012] A fixed magnet is installed in the mounting groove opposite to the mass block; the contact surface materials of the fixed magnet and the mass block are different.

[0013] Furthermore, the permanent magnet assembly includes: a mounting box, the top of which is slidably connected to the guide rail; and a permanent magnet, which is installed inside the mounting box.

[0014] Furthermore, the mounting box includes a box body and a base plate;

[0015] The box body consists of a top plate and three side plates; the tops of the three side plates are respectively connected to the three side edges of the top plate; the top of the box body is slidably connected to the guide rail.

[0016] The base plate is movably connected to the bottom of the side plate; the base plate includes a base plate body and a raised edge;

[0017] The base plate body is provided to match the box body body, and one side of the base plate body abuts against the bottom of the side plate of the box body body;

[0018] The protruding edge is located on the other side of the base plate body.

[0019] Furthermore, the spring assembly includes a spring and a fixing block;

[0020] The spring has one end mounted on the side of the mounting box facing the mounting groove;

[0021] One end of the fixing block is installed on the other end of the spring, and the other end of the fixing block is fixed to the piezoelectric beam; the outer wall of the fixing block is provided with an annular protrusion; the annular protrusion is engaged within the screw pitch of the spring.

[0022] Furthermore, the piezoelectric beam has a cross-shaped structure; the piezoelectric beam is connected to all four edges of the mounting groove; and piezoelectric ceramics are respectively provided on the top, bottom, left and right parts of the piezoelectric beam.

[0023] Furthermore, a first friction layer is fixed on the surface of the mass block.

[0024] Furthermore, a second friction layer is fixed to the surface of the fixed magnet and the mass block.

[0025] Furthermore, the first friction layer is made of polytetrafluoroethylene; the second friction layer is made of polyoxymethylene.

[0026] Furthermore, both the first friction layer and the second friction layer are etched.

[0027] Furthermore, the mounting frame consists of two long plates and two short plates; the mounting frame is arranged in the order of the long plates, the short plates, the long plates, and the short plates to form an "U" structure; the mounting groove is opened at the short plate on the left side of the mounting frame; the guide rail is provided at the long plate at the top of the mounting frame.

[0028] Compared with the prior art, the beneficial effects of this utility model are:

[0029] (1) The above-mentioned electromagnetic-piezoelectric-friction composite energy harvester is composed of a permanent magnet assembly, a piezoelectric beam and a fixed magnet coupled into a multi-stable vibration system to respond to external vibrations, thus achieving complementary advantages and enriching the power output characteristics.

[0030] (2) By using a piezoelectric beam composed of several cross-structured plates and matching the piezoelectric beam to the mounting groove. When the multiple resonant frequencies of the multi-stable vibration system of this application are in a certain integer ratio, such as 1:2 or 1:3, when one plate vibrates at the resonant frequency, the other plate will also vibrate due to nonlinear energy exchange, thereby effectively improving the conversion efficiency of the energy harvester at different frequencies and widening the output bandwidth.

[0031] (3) Through repeated collisions and separations between the mass block and the fixed magnet, and with different materials on the collision surfaces of the mass block and the fixed magnet, and by etching the materials on the collision surfaces, the roughness of the friction between the mass block and the fixed magnet is increased, thereby improving the efficiency of electron transfer and current formation. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the structure of an electromagnetic-piezoelectric-triboelectric composite energy harvester according to an embodiment of this application;

[0034] Figure 2 This is a schematic front view of an electromagnetic-piezoelectric-triboelectric composite energy harvester according to an embodiment of this application;

[0035] Figure 3 This is a side view of the piezoelectric beam of an electromagnetic-piezoelectric-triboelectric composite energy harvester according to an embodiment of this application.

[0036] Figure label:

[0037] 1. Mounting bracket; 10. Long plate; 11. Short plate; 12. Guide rail; 13. Accommodation space;

[0038] 20. Box body; 21. Permanent magnet; 220. Base plate body; 221. Projection edge;

[0039] 3. Elastic component; 30. Spring; 31. Annular protrusion; 32. Fixing block;

[0040] 40. Piezoelectric beam; 41. Piezoelectric ceramic; 42. Mass block;

[0041] 5. Fix the magnet. Detailed Implementation

[0042] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of this invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0043] In the description of this utility model, it should be understood that the terms "length", "width", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this utility model is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used to facilitate the description of this utility model and to simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0044] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0045] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0046] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0047] The following disclosure provides many different embodiments or examples for implementing various structures of the present invention. To simplify the disclosure, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the present invention. Furthermore, reference numerals may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments discussed. In addition, examples of various specific processes and materials are provided in the present invention, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0048] The embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0049] This utility model provides an electromagnetic-piezoelectric-triboelectric composite energy harvester, which includes a mounting frame 1, a permanent magnet assembly, an elastic assembly 3, a piezoelectric beam 40, and a fixed magnet 5.

[0050] Mounting bracket 1 has a mounting groove at one end. A guide rail 12 is located on the top of mounting bracket 1. A coil is mounted on the side of the guide rail 12 away from the mounting groove. The top of the permanent magnet assembly is slidably connected to the guide rail 12. One end of the spring assembly 3 is mounted on one side of the permanent magnet assembly. A piezoelectric beam 40, extending in a non-parallel direction to the guide rail 12, is connected to the edge of the mounting groove. The side of the piezoelectric beam 40 facing away from the bottom of the mounting groove is connected to the other end of the spring assembly 3. A mass block 42 is located on the side of the piezoelectric beam 40 facing the bottom of the mounting groove. The piezoelectric beam 40 is composed of plates with a cross-shaped structure. Each plate has a piezoelectric ceramic 41. A fixed magnet 5 and a mass block 42 are mounted opposite each other in the mounting groove. The contact surface materials of the fixed magnet 5 and the mass block 42 are different.

[0051] Under external vibration excitation, the mounting frame 1, composed of a permanent magnet assembly, a piezoelectric beam 40, and a fixed magnet 5, begins to respond to the external vibration, achieving complementary advantages and enriching the electrical energy output characteristics. Specifically, this energy harvesting device changes the magnetic flux of the coil by sliding the permanent magnet assembly on the guide rail 12, converting the mechanical energy of the vibration into electrical energy. Furthermore, the spring assembly 3 applies force to the piezoelectric beam 40, deforming it and thus converting the vibration energy into electrical energy. Additionally, the continuous collision and separation between the mass block 42 of the piezoelectric beam 40 and the fixed magnet 5 continuously converts collision energy into electrical energy.

[0052] Specifically,

[0053] Mounting bracket 1 consists of two long plates 10 and two short plates 11. The mounting bracket 1 is assembled into an "U" structure by following the sequence of long plates 10, short plates 11, long plates 10, and short plates 11. A mounting groove is formed on one inner wall of the mounting bracket 1. A guide rail 12 is provided on the top inner wall of the mounting bracket 1. A receiving space 13 is formed at the end of the guide rail 12 away from the mounting groove of the mounting bracket 1. The coil is mounted in the receiving space 13.

[0054] When the bottom of the mounting bracket 1 is installed on a vibration source such as a building structure, mechanical structure, or vibration table, the mounting bracket 1 will also vibrate.

[0055] The permanent magnet assembly includes a mounting box and a permanent magnet 21. The permanent magnet 21 is mounted inside the mounting box. The top of the permanent magnet assembly is slidably connected to the guide rail 12.

[0056] The mounting box includes a box body 20 and a base plate. The box body 20 is manufactured from a top plate and three side plates. The tops of the three side plates are sequentially connected to the three side edges of the top plate. The top of the box body 20 is slidably connected to a guide rail 12. The base plate is movably connected to the bottom of the box body 20. This base plate consists of a base plate body 220 and a raised edge 221. The base plate body 220 is designed to match the top plate of the box body 20; that is, the length of the base plate body 220 is the same as the length of the top plate, and the width of the base plate body 220 is slightly larger than the width of the top plate (with the sliding direction of the box body 20 along the guide rail 12 as the width direction). One side of the base plate body 220 abuts against the bottom of one of the side plates of the box body 20. The raised edge 221 is located on the other side of the base plate body 220. When the base plate body 220 is movably connected to the box body 20, the raised edge 221 is in contact with the side plate.

[0057] The permanent magnet 21 is installed inside the mounting box. After removing the base plate from the mounting box and inserting the permanent magnet 21 inside the mounting box, the base plate is then installed at the bottom of the mounting box. As the permanent magnet 21 slides along the guide rail 12 with the mounting box, the protruding edge 221 confines the permanent magnet 21 within the mounting box, preventing it from easily falling out.

[0058] Under external vibration excitation, the mounting bracket 1 drives the permanent magnet 21 to vibrate and generate displacement in the guide rail 12 in conjunction with the mounting box. The resulting displacement enables the permanent magnet 21 to interact with the coil, causing a change in the magnetic flux of the coil and converting the mechanical energy of the vibration into electrical energy.

[0059] Spring assembly 3, one end of which is mounted to the side wall of the mounting box facing the mounting slot. Spring assembly 3 includes spring 30 and fixing block 32.

[0060] One end of the spring 30 is mounted on the side wall of the mounting box facing the mounting groove, and a fixing block 32 is mounted inside the other end. The outer wall of the fixing block 32 is provided with an annular protrusion 31. The annular protrusion 31 is engaged within the thread pitch of the spring 30.

[0061] The piezoelectric beam 40 is formed by machining two plates into a cross structure. Piezoelectric ceramics 41 are sequentially installed at the top, bottom, left, and right sides of the piezoelectric beam 40. The piezoelectric beam 40 is positioned perpendicular to the extension direction of the guide rail 12 at the mounting groove and is connected to all four edges of the mounting groove. A fixing block 32 of the spring assembly 3 is fixed to one end of the piezoelectric beam 40, and a mass block 42 is fixed to the other end. A first friction layer is fixed to the surface of the mass block 42. The first friction layer is made of polytetrafluoroethylene (PTFE). When the piezoelectric beam 40 deforms due to external vibration, the piezoelectric ceramics 41 attached to the piezoelectric beam 40 generate a positive piezoelectric effect, thereby generating electrical energy. When one plate vibrates at its resonant frequency, the other plate will also vibrate due to nonlinear energy exchange, effectively improving the conversion efficiency of the energy harvester at different frequencies and broadening the output bandwidth.

[0062] Under the excitation of external vibration, the permanent magnet assembly slides along the guide rail 12 under the action of the spring assembly 3. Specifically, the permanent magnet assembly slides along the guide rail 12 away from the mounting groove until the permanent magnet 21 is suspended directly above the coil. Then, the spring 30, stretched to its limit, begins to contract due to its elastic force, thereby driving the permanent magnet assembly to move along the guide rail 12 towards the mounting groove. During this process, the magnetic flux of the coil changes, thus converting the mechanical energy of the vibration into electrical energy. At the same time, as the permanent magnet assembly moves towards the mounting groove, the elastic force of the spring 30 acts on the annular protrusion 31, causing the fixing block 32 to exert pressure on the piezoelectric beam 40, thereby deforming the piezoelectric beam 40 and generating electrical energy.

[0063] A fixed magnet 5 has a second friction layer fixed to its surface. The second friction layer is made of polyoxymethylene. The fixed magnet 5 and the mass block 42 are installed opposite each other in the mounting groove. At this time, the first friction layer and the second friction layer are in the opposite position. Both the first friction layer and the second friction layer are etched to increase the roughness of the friction layer.

[0064] When the amplitude of the permanent magnet assembly is relatively large, the mass block 42 collides with the fixed magnet 5, causing the two friction layers to come into contact in the vibration environment. Under the action of elastic force, the mass block 42 separates from the fixed magnet 5, and the two friction layers gradually separate as well, thereby realizing electron transfer and forming an electric current. As the vibration continues, the mass block 42 will repeatedly collide with the fixed magnet 5, and the collision energy will be continuously converted into electrical energy. At the same time, the collision surfaces of both the fixed magnet 5 and the mass block 42 have been etched, which greatly improves the electron transfer efficiency.

Claims

1. An electromagnetic-piezoelectric-triboelectric composite energy harvester, characterized in that, The electromagnetic-piezoelectric-triboelectric composite energy harvester includes: The mounting bracket has a mounting slot at one end; the top of the mounting bracket has a guide rail; a coil is mounted on the side of the guide rail away from the mounting slot. The permanent magnet assembly is slidably connected to the guide rail at the top; A spring assembly, one end of which is mounted on one side of the permanent magnet assembly; A piezoelectric beam is connected to the edge of the mounting groove, not parallel to the extension direction of the guide rail; the side of the piezoelectric beam facing away from the bottom of the mounting groove is connected to the other end of the spring assembly; a mass block is provided on the side of the piezoelectric beam facing the bottom of the mounting groove; the piezoelectric beam is composed of several plates with a cross structure; each plate is provided with piezoelectric ceramic. A fixed magnet is installed in the mounting groove opposite to the mass block; the contact surface materials of the fixed magnet and the mass block are different.

2. The electromagnetic-piezoelectric-triboelectric composite energy harvester according to claim 1, characterized in that, The permanent magnet assembly includes: a mounting box, which is slidably connected to the guide rail at the top; and a permanent magnet, which is installed inside the mounting box.

3. The electromagnetic-piezoelectric-triboelectric composite energy harvester according to claim 2, characterized in that, The mounting box includes a box body and a base plate; The box body consists of a top plate and three side plates; the tops of the three side plates are respectively connected to the three side edges of the top plate; the top of the box body is slidably connected to the guide rail. The base plate is movably connected to the bottom of the side plate; the base plate includes a base plate body and a raised edge; The base plate body is provided to match the box body body, and one side of the base plate body abuts against the bottom of the side plate of the box body body; The protruding edge is located on the other side of the base plate body.

4. The electromagnetic-piezoelectric-triboelectric composite energy harvester according to claim 2, characterized in that, The spring assembly includes a spring and a fixing block; The spring has one end mounted on the side of the mounting box facing the mounting groove; One end of the fixing block is installed on the other end of the spring, and the other end of the fixing block is fixed to the piezoelectric beam; the outer wall of the fixing block is provided with an annular protrusion; the annular protrusion is engaged within the screw pitch of the spring.

5. The electromagnetic-piezoelectric-triboelectric composite energy harvester according to claim 1, characterized in that, The piezoelectric beam has a cross-shaped structure; the piezoelectric beam is connected to the four edges of the mounting groove; piezoelectric ceramics are respectively provided on the top, bottom, left and right parts of the piezoelectric beam.

6. The electromagnetic-piezoelectric-triboelectric composite energy harvester according to claim 1, characterized in that, A first friction layer is fixed on the surface of the mass block.

7. The electromagnetic-piezoelectric-triboelectric composite energy harvester according to claim 6, characterized in that, A second friction layer is fixed to the surface of the fixed magnet opposite the mass block.

8. The electromagnetic-piezoelectric-triboelectric composite energy harvester according to claim 7, characterized in that, The first friction layer is made of polytetrafluoroethylene; the second friction layer is made of polyoxymethylene.

9. The electromagnetic-piezoelectric-triboelectric composite energy harvester according to claim 7, characterized in that, Both the first friction layer and the second friction layer are etched.

10. The electromagnetic-piezoelectric-triboelectric composite energy harvester according to claim 1, characterized in that, The mounting frame consists of two long plates and two short plates; the mounting frame is arranged in the order of the long plates, the short plates, the long plates, and the short plates to form an "U" structure; the mounting groove is opened at the short plate on the left side of the mounting frame; the guide rail is provided at the long plate at the top of the mounting frame.

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