A multi-pendulum vibration energy harvester based on magnetic coupling

Abstract

The present invention discloses a multi-pendulum vibration energy harvester based on magnetic coupling, which relates to the field of energy harvesters and aims to solve the problems of single working surface, large installation environment restrictions and unchangeable number of coil layers in the prior art. The technical solution adopted is to connect multiple fan-shaped pendulums on the support rod axis, install rotor magnets and counterweights on the pendulums, set an outer cylinder on the outside, and set the coils on the opposite side of the rotor magnets. The purpose of working angle self-adaptation is achieved by adopting eccentric multi-pendulums, and repulsion is provided between the multi-pendulums by arranging the magnets in the same direction, which can provide the initial angle of swing for the pendulums. Therefore, at any installation angle, the energy harvester can convert radial excitation into pendulum swing, and the working surface is wide. The coil is installed on the inner wall of the outer cylinder and is arranged parallel to the pendulum. The number of coil layers and the number of coils in each layer can be increased or decreased according to actual needs, thereby adjusting the output voltage to make it more compatible and to supply power to electrical appliances of different powers.

Description

Technical Field

[0001] The invention relates to the technical field of energy harvesters, in particular to a multi-pendulum vibration energy harvester based on magnetic coupling. Background Art

[0002] At present, the Internet of Things technology is developing rapidly. As the basic unit supporting the use of Internet of Things technology, wireless sensors are responsible for providing vital data for their effective work. In the future, it is expected that tens of billions of objects will be connected to the Internet of Things, which will require sensor networks of unprecedented scale. With such a large number, the total power consumed by sensors may reach hundreds of millions of watts. Although the energy consumption of a single sensor is low, the total energy consumption of the sensor network and the distributed, disordered, and high-entropy energy requirements of sensors have become issues that need to be urgently addressed for future development. At present, there are many sensors installed in complex environments. Although this installation method can help sensors obtain various information in complex environments more accurately and reliably, it also brings problems such as difficult battery replacement and limited equipment life. These problems will not only affect the normal operation of production activities, but are also likely to cause significant economic and property losses.

[0003] Vibration energy is a form of energy that is ubiquitous in nature and widely exists in various complex environments. The additional vibration energy generated by normal human or machine activities is unavoidable, but these vibration energies have always been regarded as waste energy due to their unstable excitation direction and unstable frequency. How to collect and utilize these vibration energies has become the focus of research. Since these vibration energies are widely distributed in complex environments, collecting these vibration energies can provide a lasting energy supply for sensors.

[0004] The device currently widely used for vibration energy harvesting is the electromagnetic vibration energy harvester, and the design focus of the existing electromagnetic vibration energy harvester is to expand the working bandwidth. The currently known ways to broaden the working bandwidth are mainly magnetic springs and mechanical springs. For details, see "Magnetic-spring based energy harvesting from human motions: Design, modeling and experiments." ("Magnetic-spring based energy harvesting from human motions: Design, modeling and experiments" in Energy Conversion and Management) and "A Magnetically Coupled ElectromagneticEnergy Harvester with Low Operating Frequency for Human Body Kinetic Energy." ("A Magnetically Coupled ElectromagneticEnergy Harvester with Low Operating Frequency for Human Body Kinetic Energy." in Micromechanics). One of the purposes of these studies is to collect vibration energy with a specific excitation direction. However, the vibration source in the actual environment may come from different directions, and the energy harvester for a single direction is extremely low in practicality in production and life.

[0005] Chinese patent CN209283065U discloses a kinetic energy collection sensor, which adopts the technical solution of comprising a base, a plurality of electromagnetic coils are evenly arranged on the top of the base, the electromagnetic coils are connected to external electrical components through wires, an energy storage pendulum and an accelerating pendulum are rotatably connected to the top center of the base, the fixed end of the energy storage pendulum and the fixed end of the accelerating pendulum are on the same axis; an accelerating bearing is arranged near the fixed end of the energy storage pendulum, the accelerating bearing is stepped, and is respectively meshed with the fixed ends of the energy storage pendulum and the accelerating pendulum for transmission; two permanent magnets are arranged on the accelerating pendulum, and the two permanent magnets face the electromagnetic coils with different magnetic poles.

[0006] Although the existing patent adopts a double pendulum structure, only a single pendulum is involved in power generation, and there is no initial swing angle between the pendulums. The power generation pendulum is accelerated by relying on a differential bearing design, and can only work in a vertical plane with a single working direction, and the number of coil layers cannot be changed.

[0007] Chinese patent CN111756126B discloses a magnetic field modulation up-frequency electromagnetic energy capture device, which adopts the following technical scheme: comprising a central axis, on which a frequency-upgrading magnetic ring, a magnetic field modulation ring, an energy-capturing magnetic ring and a base are installed from top to bottom; the frequency-upgrading magnetic ring and the energy-capturing magnetic ring are connected to the central axis through bearings, and the magnetic field modulation ring and the base are fixed to the central axis; a first magnet and an inertial mass block are installed on the frequency-upgrading magnetic ring, a high magnetic permeability material sheet is installed on the magnetic field modulation ring, a second magnet is installed on the energy-capturing magnetic ring, and a plurality of coils are evenly arranged in a ring shape on the base; under the action of external excitation, the inertial mass block drives the first magnet on the frequency-upgrading magnetic ring to rotate, generating an alternating harmonic magnetic field, and under the modulation of the magnetic field modulation ring, the harmonic frequency changes, acting on the second magnet of the energy-capturing magnetic ring, driving the energy-capturing magnetic ring to rotate at an increased speed, causing the magnetic flux inside the plurality of coils to change, generating an induced voltage.

[0008] This existing patent adopts a single pendulum structure without an initial swing angle, relies on magnetic gears to modulate the magnetic field and increase the frequency, can only work in a vertical plane, has a single working direction, and cannot change the number of coil layers.

[0009] Therefore, the above-mentioned Chinese patent is limited by its own structure and can only work in a specific plane and direction, and relies on mechanical structures such as differential bearings and magnetic gears for energy transfer. In this process, since the external energy sensed by the pendulum usually depends on its own mass, that is, for the entire system, the input energy is limited, multiple energy transfers will inevitably result in energy loss, affecting the energy capture efficiency of the device. Therefore, it is urgent to provide a vibration energy harvester that can be installed at multiple angles, has an initial swing angle, and can change the number of coils as needed. Summary of the invention

[0010] The technical problem to be solved by the present invention is to overcome the existing defects and provide a multi-pendulum vibration energy harvester based on magnetic coupling. An electromagnetic vibration energy harvester with adaptive working direction for a wide band is designed through two eccentric pendulums and the magnetic coupling between them, which can realize the collection of vibration energy under radial excitation and arbitrary installation angle, and has an adjustable working frequency range to meet the multi-directional vibration energy collection in the same plane, which can effectively solve the problems in the background technology.

[0011] In order to achieve the above-mentioned purpose, the present invention discloses a multi-pendulum vibration energy harvester based on magnetic coupling. The technical solution adopted is as follows: it includes a support rod, both ends of the support rod are connected with end covers, the upper shaft of the support rod is connected with a pendulum, there are at least two pendulums, and the pendulum is equipped with a rotor magnet, and the opposite surfaces of adjacent pendulums have permanent magnets with the same magnetic poles to form a magnetic spring. The rotor magnets with the same magnetic poles can make the adjacent pendulums have an initial swing angle, so that it is easier to start in a vibration environment; an outer cylinder is connected between the two end covers, and a coil is provided on the inner wall of the outer cylinder. The coil has multiple layers and is arranged opposite to the pendulum, and all the coils are connected; a lead through hole is opened on the outer wall of the outer cylinder, and the wiring terminal of the coil passes through the lead through hole. The coil is arranged on the inner wall and can be increased or decreased as needed, so as to facilitate the adjustment of the output induced voltage and thus have better compatibility.

[0012] As a preferred technical solution of the present invention, the pendulum is a fan-shaped block structure, and a groove for accommodating the rotor magnet is opened on its outer arc surface, and the rotor magnet can be set in the groove, and a shaft sleeve is provided on its inner arc surface to facilitate shaft connection.

[0013] As a preferred technical solution of the present invention, a receiving hole is provided on the end surface of the pendulum, and a counterweight block is provided in the receiving hole to provide counterweight, and a plurality of receiving holes are provided so that the counterweight can be adjusted as needed. The counterweight can also be achieved by making the pendulum with a high-density material, in which case the counterweight can no longer be adjusted.

[0014] As a preferred technical solution of the present invention, the coils in each layer in the outer cylinder are wound in the same direction, so that the currents generated therein are directed in the same direction.

[0015] As a preferred technical solution of the present invention, the inner wall of the outer cylinder is provided with a third accommodating hole, and the coil is in the third accommodating hole; the outer wall of the outer cylinder is provided with a first wire groove and a second wire groove, and the first wire groove and the second wire groove intersect; the lead-in through hole also includes a first lead-in through hole and a second lead-in through hole, and the two ends of the coil pass through the first lead-in through hole and the second lead-in through hole respectively. The connecting wires between the coils can be accommodated through the outer wire grooves.

[0016] As a preferred technical solution of the present invention, the first lead wire through hole and the second lead wire through hole are located at the intersection of the first wire groove and the second wire groove.

[0017] As a preferred technical solution of the present invention, the lead wire through holes on each of the second wire slots are the same, and the first lead wire through holes and the second lead wire through holes are alternately arranged on the first wire slots.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention achieves the purpose of adaptive working angle by adopting an eccentric multi-pendulum, and then provides repulsion between the multi-pendulums by arranging magnets in the same direction, that is, when the pendulum is stable under the action of gravity, the repulsion can provide the pendulum with an initial angle of swing. Therefore, at any installation angle, the energy harvester can convert radial excitation into pendulum swing, and the working surface is wide. The coil is installed on the inner wall of the outer cylinder and arranged opposite to the pendulum. The number of layers of the coil and the number of coils in each layer can be increased or decreased according to actual needs, thereby adjusting the output voltage to make it more compatible and able to power electrical appliances of different powers. The multi-pendulum in the present invention can not only directly sense external energy, but also be used as a power generation pendulum to capture energy. There is no energy transfer process, which reduces the energy loss rate.

[0019] Furthermore, the present invention introduces a magnetic spring through a magnet combination to imitate the effect of a butterfly vibrating its wings, which not only reduces the energy loss caused by the collision but also expands the bandwidth of the energy harvester.

[0020] Furthermore, by changing the magnetic spring stiffness and the mass of the pendulum, the vibration frequency of the pendulum can be adjusted so that the vibration frequency of the pendulum matches the natural frequency of the machine, thereby achieving the highest energy output. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is an exploded view of the structure of the present invention;

[0022] Figure 2 This is a schematic diagram of the first pendulum structure of the present invention;

[0023] Figure 3 This is a schematic diagram of the second pendulum structure of the present invention;

[0024] Figure 4 This is a schematic diagram of the end cover structure of the present invention;

[0025] Figure 5 This is a schematic diagram of the outer cylinder structure of the present invention;

[0026] Figure 6 It is an exploded view of the structure of the present invention in the assembled state.

[0027] In the figure: 1. support rod; 2. first pendulum; 201. first sleeve; 202. first receiving hole; 203. first groove; 3. second pendulum; 301. second sleeve; 302. second receiving hole; 303. second groove; 401. base; 402. top cover; 403. third sleeve; 404. boss; 6. outer cylinder; 601. annular groove; 602. first wire groove; 603. second wire groove; 604. first lead through hole; 605. second lead through hole; 606. third receiving hole; 7. bearing; 8. rotor magnet; 9. coil; 10. counterweight. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example 1

[0029] like Figures 1 to 6 As shown, the present invention discloses a multi-pendulum vibration energy harvester based on magnetic coupling, and the technical solution adopted is that it includes a support rod 1, and the two ends of the support rod 1 are connected with end caps, such as Figure 4 As shown, the end cover includes a base 401 and a top cover 402. The base 401 and the top cover 402 have the same structure. Taking the base 401 as an example, Figure 4 As shown, the base 401 includes a cover body, a boss 404 is coaxially arranged on the cover body, a third sleeve 403 is coaxially arranged on the boss 404, and the third sleeve 403 is interference fit with the support rod 1.

[0030] The first pendulum 2 and the second pendulum 3 are rotatably connected to the support rod 1 through the bearing 7. Figure 2 As shown, the main body of the first pendulum 2 is a sector-shaped block, and a first sleeve 201 is provided at each end of the small radius arc surface on the inner side thereof, and a first groove 203 is provided on the large radius arc surface on the outer side thereof. The first groove 203 is a circular groove, and its end surface is provided with three first receiving holes 202 distributed in a sector shape. The first receiving hole 202 is provided with a counterweight block 10, and the first groove 203 is provided with a rotor magnet 8.

[0031] like Figure 3 As shown, the difference between the second pendulum 3 and the first pendulum 2 is that a second sleeve 301 is provided in the middle section of the small radius arc surface inside the second pendulum 3. Similarly, the rotor magnet 8 is installed in the second groove 303 on the large radius arc surface of the second pendulum 3, and the counterweight 10 is installed in the second receiving hole 302 on the end surface.

[0032] In order to make the two pendulums form an initial swing angle, permanent magnets with the same magnetic poles are installed on the opposite surfaces of the first pendulum 2 and the second pendulum 3 respectively, and the positions are opposite to each other to form a magnetic spring.

[0033] There is an outer cylinder 6 between the base 401 and the top cover 402, such as Figure 5As shown, annular grooves 601 corresponding to the position of the boss 404 and matching in size are provided on the end faces of both ends of the outer cylinder 6, and a third accommodating hole 606 is opened on the inner wall of the outer cylinder 6. There are 7 third accommodating holes 606 in each circle, and 4 circles are provided. A horizontal annular first wire groove 602 and a vertically arranged second wire groove 603 are provided on the outer wall of the outer cylinder 6. The first wire groove 602 is provided with four layers, and the second wire groove 603 is provided with fourteen lines, which are evenly distributed. A first lead wire through hole 604 and a second lead wire through hole 605 are provided at the intersection of the first wire groove 602 and the second wire groove 603. The first lead wire through hole 604 and the second lead wire through hole 605 on each first wire groove 602 are arranged alternately, and each second wire groove 603 has only one of the first lead wire through hole 604 and the second lead wire through hole 605. The first lead wire through hole 604 is coaxial with the third accommodating hole 606, and the second lead through hole 605 is located between two adjacent third accommodating holes 606 on the left and right.

[0034] A coil 9 is arranged in the third accommodating hole 606 on the inner wall of the outer cylinder 6. The coils 9 on the same horizontal plane have the same winding direction, and the two ends of the coil 9 pass through the first lead through hole 604 and the second lead through hole 605 respectively. The coils 9 on the same horizontal plane are connected in series, and the serially connected copper wires are arranged along the first wire groove 602. The copper wires of different planes are led out according to the arrangement of the first wire groove 602 and then gathered in a second wire groove 603. The multi-layer planar copper wires are connected in parallel and then led out from the second wire groove 603. The other second wire grooves 603 are spare wire grooves.

[0035] Working principle of the present invention:

[0036] When the energy harvester is installed at any angle, the first pendulum 2 and the second pendulum 3 will automatically rotate to a specific angle under the action of gravity, and since the rotor magnets 8 installed on the same side of the first pendulum 2 and the second pendulum 3 have the same polarity, this provides repulsion between the two pendulums, so there is an initial swing angle between the pendulums. When the first pendulum 2 and the second pendulum 3 sense the vibration excitation generated by the operation of the machine, the first pendulum 2 and the second pendulum 3 begin to swing around the support rod 1 because the counterweight block 10 increases the weight of the pendulum. As the frequency and amplitude of the external excitation increase, the swing angle of the pendulum gradually expands, and the energy output gradually increases. When the swing of the first pendulum 2 and the second pendulum 3 exceeds the critical value, the pendulum begins to rotate around the support rod 1. The magnetic spring formed by the permanent magnets of the first pendulum 2 and the second pendulum 3 avoids collision and energy loss between the first pendulum 2 and the second pendulum 3, and also increases the vibration frequency of the pendulum. In the whole process, the rotor magnets 8 installed on the first pendulum 2 and the second pendulum 3 cut the coil 9 in the third receiving hole 606, and capture the vibration energy through electromagnetic induction to generate electrical energy. In addition, the magnetic force of the permanent magnets can be varied to adapt to the natural frequency of the machine, thus achieving the highest energy output.

[0037] As required, the first pendulum 2 and the second pendulum 3 can be made of high-density materials so that they have sufficient weight to eliminate the counterweight 10. However, this method will cause the mass of the pendulum to be fixed and unable to be adjusted.

[0038] According to the needs, the number of pendulums can be changed, such as three pendulums, four pendulums, etc., but the more pendulums there are, the smaller the swing angle is. Electromagnetic induction relies on the change of magnetic flux, and the magnetic flux change rate can be increased by reducing the size of the magnet and the coil in the circumferential direction of the device. Compared with a larger number of pendulums, the double pendulum structure of Example 1 can rely on repulsion to provide an initial angle and ensure a larger swing angle, which is a better solution.

[0039] As needed, the coils 9 of each column can be connected in series. In this case, the copper wires in series are stored in the second wire slots 603. After the series connection, the terminal ends are gathered in a first wire slot 602 and connected in parallel in the first wire slot 602 before being led out. In this case, the other first wire slots 602 are reserved.

[0040] The circuits and mechanical connections involved in the present invention are conventional means used by those skilled in the art, and technical inspiration can be obtained through a limited number of experiments, which are common knowledge.

[0041] Components not described in detail herein are prior art.

[0042] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A multi-pendulum vibration energy harvester based on magnetic coupling, comprising a support rod (1), both ends of the support rod (1) are connected to end caps, and the upper axis of the support rod (1) is connected to a pendulum, characterized in that: There are at least two pendulums, and the pendulums are equipped with rotor magnets (8). Permanent magnets with the same magnetic poles are provided on opposite surfaces of adjacent pendulums to form a magnetic spring. An outer cylinder (6) is connected between the two end covers. The inner wall of the outer cylinder (6) is provided with a coil (9). The coil (9) has multiple layers and is arranged opposite to the pendulums. All the coils (9) are connected. The outer wall of the outer cylinder (6) is provided with a lead through hole, and the wiring terminal of the coil (9) passes through the lead through hole. The pendulum is a fan-shaped block structure, and a groove for accommodating the rotor magnet (8) is provided on its outer curved surface, and a shaft sleeve is provided on its inner curved surface. The shaft sleeve is sleeved on the support rod (1).

2. The multi-pendulum vibration energy harvester based on magnetic coupling according to claim 1 is characterized in that: A receiving hole is provided on the end surface of the pendulum, and a counterweight block (10) is arranged in the receiving hole.

3. The multi-pendulum vibration energy harvester based on magnetic coupling according to claim 1, characterized in that: The coils (9) of each layer in the outer cylinder (6) are wound in the same direction.

4. The multi-pendulum vibration energy harvester based on magnetic coupling according to claim 1 or 3, characterized in that: The inner wall of the outer cylinder (6) is provided with a third accommodating hole (606), and the coil (9) is in the third accommodating hole (606); the outer wall of the outer cylinder (6) is provided with a first wire groove (602) and a second wire groove (603), and the first wire groove (602) and the second wire groove (603) intersect each other; the lead wire through hole further comprises a first lead wire through hole (604) and a second lead wire through hole (605), and two ends of the coil (9) respectively pass through the first lead wire through hole (604) and the second lead wire through hole (605).

5. The multi-pendulum vibration energy harvester based on magnetic coupling according to claim 4, characterized in that: The first lead wire through hole (604) and the second lead wire through hole (605) are located at the intersection of the first wire groove (602) and the second wire groove (603).

6. The multi-pendulum vibration energy harvester based on magnetic coupling according to claim 5, characterized in that: The lead wire through holes on each of the second wire grooves (603) are identical, and the first lead wire through holes (604) and the second lead wire through holes (605) are alternately arranged on the first wire groove (602).

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