A multi-directional extremely low frequency vibration energy harvesting device based on a limited double pendulum system

Abstract

The present application relates to a kind of multidirectional extremely low frequency vibration energy harvesting device based on limiting double pendulum system, belong to vibration energy harvesting field.The device is composed of limiting double pendulum module and energy conversion module, the limiting double pendulum module includes encapsulation shell, cycloidal A, mass block, cycloidal B, movable permanent magnet and Teflon pipe, the energy conversion module includes movable permanent magnet, energy converter, Teflon pipe and fixed permanent magnet, energy converter can be selected according to different energy conversion principle, such as coil (electromagnetic induction), piezoelectric cantilever beam (piezoelectric effect), magnetoelectric composite material (magnetoelectric effect), friction electricity material (triboelectric effect) etc., the two modules are coupled by movable permanent magnet and Teflon pipe for sharing;The energy harvesting device can respond to multidirectional excitation, with extremely low operating frequency, while simple structure, low mechanical fatigue, high output power, adapt to wave energy, wind energy, mechanical vibration energy and many other energy harvesting fields.

Description

Technical Field

[0001] This invention belongs to the field of vibration energy harvesting and relates to a multi-directional ultra-low frequency vibration energy harvesting device based on a limit double pendulum system. Background Technology

[0002] Currently, power supply for a large number of distributed sensors is one of the main challenges faced by IoT terminals. Meanwhile, low-power sensors can utilize energy harvesting devices to collect various energy sources from the surrounding environment to achieve "self-powering." Based on this, various vibration energy harvesters have been created using friction, electromagnetic induction, and piezoelectric effects to convert mechanical energy into electrical energy to supply low-power sensors. This eliminates the need for regular power supply replacements and maintenance, frees them from external cable constraints, and maximizes the advantages of distributed sensors, which are available in a wide area and in large numbers.

[0003] Existing vibration energy harvesters can power some low-power electronic products, but they still have some drawbacks. For example, the multimodal low-frequency electromagnetic vibration energy harvester proposed in Chinese invention patent CN207368855, although capable of harvesting vibration energy in five modes, still has directional limitations. Similarly, P. Jiao et al., in their article "Oscillatory magnetic piezoelectric nanogenerators under low-frequency and low-amplitude excitations" in *Sustainable Energy Technologies and Assessments*, Vol. 52, 2022, 102022, proposed an oscillating magnetic piezoelectric nanogenerator that can respond to low-frequency, low-amplitude excitations, but its response frequency is still higher than 1Hz. The eye-like wave energy harvester proposed in Chinese invention patent CN113803205A, while effectively collecting vibration energy under low-frequency irregular excitation, has an overly complex structure and is prone to mechanical fatigue or even damage. For example, A. Ning et al., in their article "Optimization of a Rolling Triboelectric Nanogenerator Based on the Nano-Micro Structure for Ocean Environmental Monitoring" in *ACS Omega*, Vol. 6, 2021, 21059-21065, proposed a multi-directional rolling triboelectric nanogenerator. While it achieves a 360° excitation response, its output power is less than 1mW, making it difficult to apply in practical situations. Since the 21st century, power supply for a large number of distributed sensors has been one of the major challenges faced by IoT terminals. Meanwhile, low-power sensors can utilize energy harvesting devices to collect various energy sources from the surrounding environment to achieve "self-powering." Based on this, various vibration energy harvesters have been created using friction effects, electromagnetic induction, and piezoelectric effects to convert mechanical energy into electrical energy to supply low-power sensors. This eliminates the need for regular power supply replacements and maintenance, frees them from external cable constraints, and maximizes the advantages of distributed sensors, which have a wide area and large number of sensors. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a multi-directional extremely low-frequency vibration energy harvesting device based on a limit double pendulum system, which addresses the shortcomings of current vibration energy harvesting devices and solves the problems that vibration energy harvesting devices cannot simultaneously meet the requirements of multi-directional, low frequency, high output, and simple structure.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A multi-directional ultra-low frequency vibration energy harvesting device based on a limited double pendulum system is disclosed. The device includes a limited double pendulum module and an energy conversion module. The limited double pendulum module comprises a housing 1, a pendulum A2, a mass block 3, a pendulum B4, a movable permanent magnet 5, and a Teflon tube 7. In the naturally stationary state of the energy harvesting device, the lower surface of the mass block is as close as possible to the upper surface of the Teflon tube, ensuring that the Teflon tube does not affect the oscillation of the mass block. Simultaneously, the pendulum B has a margin, meaning its length is greater than the distance between the lower surface of the mass block and the upper surface of the Teflon tube in the stationary state. The spacing of the upper surface of the movable permanent magnet; the energy conversion module includes a movable permanent magnet 5, an energy converter 6, a Teflon tube 7, and a fixed permanent magnet 8. The Teflon tube and the fixed permanent magnet are both fixed to the encapsulation shell. The energy converter can be selected according to different energy conversion principles, such as coil (electromagnetic induction), piezoelectric cantilever beam (piezoelectric effect), magnetoelectric composite material (magnetoelectric effect), triboelectric material (triboelectric effect), etc.; the limiting double pendulum module is located above the energy conversion module, and the two modules are coupled together because they share the movable permanent magnet and the Teflon tube.

[0007] Furthermore, the encapsulation shell seals the internal structure of the collection device.

[0008] Furthermore, the upper end of the cycloidal A, the Teflon tube, and the fixed permanent magnet are all connected to the encapsulation shell.

[0009] Furthermore, the movable permanent magnet and the fixed permanent magnet are cylindrical in shape, with the magnetic poles located on the top and bottom surfaces of the permanent magnet, and the parameters are consistent.

[0010] Furthermore, the movable permanent magnet and the fixed permanent magnet are in a state of like poles repulsion, and the movable permanent magnet can vibrate up and down inside the Teflon tube.

[0011] Furthermore, in the naturally static state of the energy harvesting device, the connection point between the encapsulation shell and cycloid A, cycloid A, the center point of the mass block, the axis of the Teflon tube, the center point of the movable permanent magnet, and the center point of the fixed permanent magnet are all located on the same vertical line.

[0012] Furthermore, the only difference between the cycloid A and the cycloid B is their length.

[0013] Furthermore, the diameter of the small hole on the upper surface of the Teflon tube is slightly larger than the diameter of the cycloidal B.

[0014] Furthermore, the center height of the energy converter is consistent with the center height of the movable permanent magnet in the natural static state of the energy harvesting device.

[0015] The beneficial effects of this invention are:

[0016] 1. This invention utilizes the reverse thinking of traditional research on double pendulum systems (how to suppress chaotic motion in double pendulum systems) to transform multi-directional irregular chaotic motion into unidirectional controllable motion of a movable permanent magnet, thereby generating energy accumulation and enabling the energy harvesting device to respond to multi-directional vibration excitation and have high output power.

[0017] 2. By introducing the nonlinear repulsive force of magnetic levitation and optimizing the parameters of Teflon tube, energy converter, and permanent magnet, the energy harvesting device can achieve high output power even under extremely low frequency vertical vibration excitation or low-speed horizontal flow excitation.

[0018] 3. By using a shared movable permanent magnet and Teflon tube to couple the two modules, the structure is simple, does not include common direction conversion components such as steering wheels and bearings, has low mechanical fatigue and mechanical loss, low cost, and is easy to manufacture.

[0019] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0020] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0021] Figure 1 This is a three-dimensional model of a multi-directional ultra-low frequency vibration energy harvesting device based on a limit double pendulum system designed according to the present invention.

[0022] Figure 2 The images show the front view and three-dimensional view of the designed energy harvesting device under different states. Figure 2 (a) Figure 2 (b) Figure 2 (c) is a front view of the energy harvesting device in a static state, a vertical vibration excitation state, and a horizontal vibration excitation state. Figure 2 (d) Figure 2 (e) Figure 2 (f) shows the three-dimensional view in three states;

[0023] Figure 3 The image shows a 3D model of a multi-directional ultra-low frequency vibration energy harvesting device based on a constrained double pendulum system, utilizing different principles. Figure 3 (a) Figure 3 (b) Figure 3 (c) Figure 3(d) Based on electromagnetic induction, magnetoelectric effect, piezoelectric effect and triboelectric effect respectively, the energy conversion devices are coil, magnetoelectric composite material, piezoelectric cantilever beam and triboelectric material respectively.

[0024] Reference numerals in the attached diagram: 1. Encapsulation shell, 2. Cycloidal A, 3. Mass block, 4. Cycloidal B, 5. Movable permanent magnet, 6. Energy converter, 7. Teflon tube, 8. Fixed permanent magnet. Detailed Implementation

[0025] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0026] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures, and should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0027] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not 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, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0028] Figure 1 This is a three-dimensional model of a multi-directional ultra-low frequency vibration energy harvesting device based on a limited double pendulum system designed in this invention. The energy converter can be selected according to different energy conversion principles, such as coil (electromagnetic induction), piezoelectric cantilever beam (piezoelectric effect), magnetoelectric composite material (magnetoelectric effect), triboelectric material (triboelectric effect), etc.

[0029] This embodiment provides a multi-directional ultra-low frequency electromagnetic wave energy harvester based on a limit-pendulum system, including a limit-pendulum module and an energy conversion module. The limit-pendulum module consists of an encapsulation shell 1, a pendulum A2, a mass block 3, a pendulum B4, a movable permanent magnet 5, and a Teflon tube 7. In the natural static state of the energy harvester, the lower surface of the mass block and the upper surface of the Teflon tube are as close as possible, ensuring that the Teflon tube does not affect the oscillation of the mass block. At the same time, the pendulum B has a margin, that is, the length of the pendulum B is greater than the distance between the lower surface of the mass block and the upper surface of the movable permanent magnet in the static state. The energy conversion module consists of the movable permanent magnet 5, an energy converter 6, a Teflon tube 7, and a fixed permanent magnet 8. The energy converter selects the coil based on the principle of electromagnetic induction. The limit-pendulum module is located above the energy conversion module, and the two modules are coupled together because they share the movable permanent magnet and the Teflon tube.

[0030] Figure 2 The images show the front view and three-dimensional view of the designed energy harvesting device under different states. Figure 2 (a) Figure 2 (b) Figure 2 (c) is a front view of the energy harvesting device in a static state, a vertical vibration excitation state, and a horizontal vibration excitation state. Figure 2 (d) Figure 2 (e) Figure 2 (f) shows the three-dimensional view under three states. Using the above scheme, when the energy harvester is vertically excited by wave undulations, the movable permanent magnet will be subjected to the nonlinear repulsive force of the fixed permanent magnet, the pulling force of the mass block's upward motion, and its own gravity, causing it to reciprocate within the Teflon tube. This causes the coil to cut magnetic field lines, generating an induced electromotive force (e.g., ...). Figure 2 (as shown in e); When the energy harvester is excited horizontally by the ocean current, the movable permanent magnet experiences a nonlinear repulsive force from the fixed permanent magnet, an inertial force generated by the left-right swinging of the mass block, and its own gravity, causing it to reciprocate within the Teflon tube. Similarly, the coil will cut the magnetic field lines to generate an induced electromotive force (as shown in e). Figure 2 (as shown in f). In addition, by studying and optimizing the nonlinear repulsive force, the pulling force of the mass block on the movable permanent magnet, the height of the Teflon tube, and the coil parameters, the energy harvester can respond to smaller vertical excitation frequencies, amplitudes, or horizontal velocities, and the output power of the energy harvester is increased.

[0031] In this embodiment, the length of cycloid A is 90mm; the weight of the mass block is 41.7g; the length of cycloid B is 50mm; the parameters of the Teflon tube are φ20mm*110mm, wall thickness 2mm, and the tube opening is sealed with a small hole located on the tube axis with a diameter slightly larger than the diameter of the cycloid; the parameters of the movable permanent magnet and the fixed permanent magnet are φ20mm*20mm, mass 45g, remanence 8612Oe, and the parameters of the coil are inner diameter 24mm, outer diameter 54mm, height 15mm, wire diameter 0.1mm, and internal resistance 4.09kΩ.

[0032] Figure 3 These are three-dimensional model diagrams of multi-directional ultra-low frequency vibration energy harvesting devices based on a limit double pendulum system, utilizing different principles. Figure 3 (a) Figure 3 (b) Figure 3 (c) Figure 3 (d) Based on electromagnetic induction, magnetoelectric effect, piezoelectric effect, and triboelectric effect, the energy conversion devices are coil, magnetoelectric composite material, piezoelectric cantilever beam, and triboelectric material, respectively. When the mass block at the end of the piezoelectric cantilever beam is made of ferromagnetic material, the piezoelectric cantilever beam will vibrate with the vibration of the movable permanent magnet inside the Teflon tube, causing the two poles of the piezoelectric material to generate the same number of charges with opposite polarities. When the magnetoelectric composite material is placed outside the Teflon tube, the magnetostrictive material will generate strain and stress with the vibration of the movable permanent magnet inside the Teflon tube, and then transfer the stress to the piezoelectric material to generate charges. When the triboelectric material is located on the inner wall of the Teflon tube, the friction caused by the reciprocating motion of the movable permanent magnet causes the triboelectric materials with different electron loss capabilities to generate relative displacement, thereby generating charges.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A multi-directional ultra-low frequency vibration energy harvesting device based on a limited double pendulum system, comprising a limited double pendulum module and an energy conversion module, wherein the limited double pendulum module is located above the energy conversion module, characterized in that: The limiting double pendulum module includes: a package shell (1), a cycloid A (2), a mass block (3), a cycloid B (4), a movable permanent magnet (5), and a Teflon tube (7). When the energy harvesting device is in a natural static state, the lower surface of the mass block is close to the upper surface of the Teflon tube, and the Teflon tube does not affect the swing of the mass block. The cycloid B has a margin, meaning that the length of the cycloid B is greater than the distance between the lower surface of the mass block and the upper surface of the movable permanent magnet in the static state. The energy conversion module includes a movable permanent magnet (5), an energy converter (6), a Teflon tube (7), and a fixed permanent magnet (8); the Teflon tube and the fixed permanent magnet are both fixed to the encapsulation shell; Energy converters are selected based on different energy conversion principles: If the principle is electromagnetic induction, then a coil should be selected; If the principle is based on piezoelectric effect, then a piezoelectric cantilever beam should be chosen; If it is a magnetoelectric effect, then a magnetoelectric composite material should be selected; If it is a triboelectric effect, then a triboelectric material should be selected; The limiting double pendulum module and the energy conversion module are coupled by sharing a movable permanent magnet and a Teflon tube; The movable permanent magnet and the fixed permanent magnet are in a state of like pole repulsion, and the movable permanent magnet can vibrate up and down inside the Teflon tube. When the energy harvesting device is excited in the horizontal direction, the movable permanent magnet is subjected to the nonlinear repulsive force of the fixed permanent magnet, the inertial force generated by the left and right swing of the mass block, and its own gravity, and reciprocates inside the Teflon tube. At the same time, the coil cuts the magnetic field lines to generate an induced electromotive force.

2. The multi-directional ultra-low frequency vibration energy harvesting device based on a limit double pendulum system according to claim 1, characterized in that: The encapsulation shell seals the internal structure of the acquisition device.

3. The multi-directional ultra-low frequency vibration energy harvesting device based on a limit double pendulum system according to claim 1, characterized in that: The upper end of the cycloidal A, the Teflon tube, and the fixed permanent magnet are all connected to the encapsulation shell.

4. The multi-directional ultra-low frequency vibration energy harvesting device based on a limit double pendulum system according to claim 1, characterized in that: The movable permanent magnet and the fixed permanent magnet are cylindrical in shape, with magnetic poles located on the top and bottom surfaces of the permanent magnet, and their parameters are consistent.

5. A multi-directional ultra-low frequency vibration energy harvesting device based on a limit double pendulum system according to claim 1, characterized in that: In the natural static state of the energy harvesting device, the connection point between the encapsulation shell and cycloid A, cycloid A, the center point of the mass block, the axis of the Teflon tube, the center point of the movable permanent magnet, and the center point of the fixed permanent magnet are all located on the same vertical line.

6. The multi-directional ultra-low frequency vibration energy harvesting device based on a limit double pendulum system according to claim 1, characterized in that: The cycloids A and B have different lengths.

7. The multi-directional ultra-low frequency vibration energy harvesting device based on a limit double pendulum system according to claim 1, characterized in that: The diameter of the small hole on the upper surface of the Teflon tube is larger than the diameter of the cycloidal B.

8. A multi-directional ultra-low frequency vibration energy harvesting device based on a limit double pendulum system according to claim 1, characterized in that: The center height of the energy converter is consistent with the center height of the movable permanent magnet in the natural static state of the energy harvesting device.

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