E-shaped master-slave beam composite energy harvesting device based on magnetic coupling

Abstract

The invention discloses a two-degree-of-freedom nonlinear energy capture device based on a piezoelectric effect and an electromagnetic induction coupling principle, and belongs to the field of environmental vibration energy conversion. The device comprises a base, an E-shaped cantilever beam structure, a permanent magnet assembly, a fixed clamping plate assembly, a base fixing clamp, an adjustable clamping device and a coil. The E-shaped cantilever beam is composed of a main beam and an auxiliary beam, piezoelectric elements are installed on the main beam and the auxiliary beam respectively, movable magnets are arranged at the free ends of the main beam and the auxiliary beam respectively, and the movable magnets and fixed magnets installed on the vertical frame of the base face each other to form two pairs of repulsive magnetic coupling units. The distance between the two pairs of magnetic coupling units can be independently adjusted so as to control the nonlinear coupling strength and the steady state trap depth of the main beam and the auxiliary beam. Under the action of external low-frequency excitation, the E-type master-slave beam generates coupling vibration, the piezoelectric plate generates strain charges to output electric energy, and meanwhile, the moving magnet cuts magnetic induction lines to induce current in the coil, so that collaborative energy harvesting of a piezoelectric field and an electromagnetic field is realized.

Description

Technical Field

[0001] This invention relates to the field of environmental vibration energy harvesting and energy conversion, specifically to a two-degree-of-freedom nonlinear composite energy harvesting device based on piezoelectric effect and electromagnetic induction coupling. Background Technology

[0002] With the rapid development of the Internet of Things, structural health monitoring, intelligent transportation, and unmanned systems, a large number of low-power sensors and wireless nodes are being deployed on vehicles, bridges, railways, and industrial equipment. These nodes have an urgent need for long-term, low-maintenance self-powered solutions. Traditional battery-based power supply methods have significant shortcomings in terms of maintenance costs, lifespan, and environmental impact. Grid power supply requires complex wiring and has high installation and maintenance costs; while battery power supply is easy to deploy, it has limited energy density, short battery life, and frequent maintenance. To achieve long-term autonomous power supply, vibration energy harvesting has become a key direction. Traditional piezoelectric or electromagnetic energy harvesting devices are mostly linear single-degree-of-freedom structures, which suffer from narrow resonant bandwidth and low output power. Although composite energy harvesters can combine piezoelectric and electromagnetic effects, they are complex in structure, large in size, and difficult to balance wide bandwidth and high efficiency. Therefore, a nonlinear dual-degree-of-freedom composite energy harvesting device with a compact structure, wide bandwidth, and high energy conversion efficiency is needed to adapt to the low-frequency vibration environment in industrial settings and achieve energy harvesting and utilization. Summary of the Invention

[0003] The purpose of this invention is to provide a dual-degree-of-freedom nonlinear piezoelectric-electromagnetic composite energy harvesting device based on an E-type master-slave beam and dual independent repulsive magnetic coupling, which achieves wideband response and high energy output by introducing a nonlinear magnetic coupling structure.

[0004] The technical solution of this invention is: a nonlinear energy harvesting device, comprising a base, an E-type cantilever beam structure, a permanent magnet assembly, a fixed clamping plate assembly, an adjustable clamping device, a coil, and a base fixing fixture. The E-type cantilever beam structure consists of a main beam and a slave beam, forming a master-slave coupled two-degree-of-freedom system; a pair of moving magnets are arranged at the free ends of the main and slave beams, forming two pairs of repulsive magnetic couplings with corresponding fixed magnets on the vertical frame of the base; the spacing between the two pairs of magnetic coupling units can be independently adjusted to control the potential well depth of the master mode and the slave mode, respectively; under vibration excitation, the system generates a multi-steady-state nonlinear response, broadening the resonant frequency band; piezoelectric plates are arranged on the surfaces of the main and slave beams to output piezoelectric energy, while the moving magnets cut magnetic field lines in the coil to generate induced electrical energy; the dual-channel energy is rectified and output in parallel to the energy storage module, realizing efficient energy composite harvesting.

[0005] The open end of the E-type cantilever beam is fixed to the clamp plate by locking bolts, and the clamp plate assembly is fixed to the vertical structure by locking bolts.

[0006] The piezoelectric element is bonded to the metal beam with conductive epoxy adhesive.

[0007] The first and second moving magnets are fixed to the free ends of the main beam and the secondary beam, respectively. The first and second fixed magnets are fixed to the vertical frame of the base and the vertical frame. The position of the permanent magnets on the frame is adjustable. All of the above magnets are made of neodymium iron boron.

[0008] The coil is a copper coil, fixed on the vertical frame on the right side of the base, and its position is adjustable.

[0009] The vertical frame of the base is fixed to the base plate with locking bolts, and its position is adjustable.

[0010] The beneficial effects of this invention include: (1) The compact structure and modular design facilitate manufacturing and parameter adjustment, and adapt to different vibration environments; (2) The E-type master-slave beam structure realizes master-slave mode coupling and significantly broadens the energy harvesting frequency band; (3) Two pairs of magnetic coupling units can adjust the magnetic gradient to form a controllable nonlinear potential energy trap, which can flexibly control the distribution of nonlinear potential energy and the frequency matching range, significantly broaden the energy trapping bandwidth and improve the output power.

[0011] (4) Realize piezoelectric and electromagnetic multi-field coordinated energy capture, alleviate the problem of mismatch between external excitation frequency and resonant frequency, and improve the efficiency of vibration energy collection.

[0012] The present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0013] Figure 1 Schematic diagram of a specific embodiment of the present invention; Figure 2 Front view diagram of a specific embodiment of the present invention; Figure 3 Schematic diagram of the E-type cantilever beam structure of the present invention; Figure 4 Schematic diagram of the fixing clamp assembly structure of the present invention; Figure 5 A schematic diagram of the base structure of this invention; Figure 6 Schematic diagram of the structure of embodiment 2 of the present invention; Detailed Implementation To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail with reference to the accompanying drawings and embodiments.

[0014] Example 1: Referring to Figures 1-6, the present invention includes a base 1, left and right vertical frames 2 and 12, an E-shaped cantilever beam 13, a permanent magnet assembly 8, a fixed clamping plate assembly 4, a coil 9, and an adjustable clamping device 10. The E-shaped cantilever beam 13 consists of a main beam 13-1 and a secondary beam, which are arranged parallel to each other in the horizontal plane. The open ends are fixed to the left vertical frame 2 via the fixed clamping plate assembly 4. A first moving magnet 8-1 is provided at the end of the main beam 13-1, and a second moving magnet 8-2 is provided at the end of the secondary beam 13-2. First and second fixed magnets 8-3 and 8-4 are respectively installed on the vertical frames on both sides of the base. The moving and fixed magnets have the same relative magnetic poles, forming two pairs of repulsive magnetic coupling units, the spacing of which can be independently adjusted by a sliding groove and a threaded structure. The base plate 11 is provided with a sliding groove 15, and a movable bracket 14 is provided in the sliding groove for adjusting the relative position of the coil 9 and the moving magnet. When the device is working, the base drives the E-type cantilever beam to generate coupled vibration under external excitation. The piezoelectric elements 5, 6, and 7 generate deformation and output charge. The moving magnet induces an electromotive force in the coil 9 during the process of cutting the magnetic field lines, realizing piezoelectric and electromagnetic composite energy capture.

[0015] like Figure 1 As shown, base 1 is used to connect to an external vibration source, and vertical structural plates 2 and 12 are connected to base 1. The open end of the E-type cantilever beam structure 13 is fixedly connected to the vertical structure 2 of the base through a clamping plate assembly 4 and locking bolts. The E-type cantilever beam 13 consists of a main beam 13-1 and a secondary beam 13-2, which are parallel to each other in the horizontal plane. The main beam 13-1 of the E-type cantilever beam structure 13 includes a first magnet 8-1 and a locking bolt, and the first movable magnet 8-1 is fixed to the end of the main beam 13-1. The secondary beam 13-2 includes a second movable magnet 8-2 and a locking bolt. The open end of the E-type cantilever beam 13 is fixedly connected to the vertical frame 2 of the base through a fixing clamping plate assembly 4. The fixing clamping plate assembly is fixed to the free end of the secondary beam 13-2 by locking bolts. When the fixing clamping plate assembly is locked, the first fixed magnet 8-3 is fixed.

[0016] Specifically, the number of threaded holes on the vertical structural plate 2 can be flexibly adjusted in order to stably fix the following clamping plate assembly, E-type cantilever beam structure 13, and first fixed magnet 8-3.

[0017] like Figure 4 As shown, the main beam 13-1 includes a first piezoelectric element 5 and a first metal beam; the secondary beam 13-2 includes a third piezoelectric element 7 and a second rectangular piezoelectric metal beam; the first piezoelectric element 5 and the third piezoelectric element 7 are bonded to the first metal beam with conductive epoxy adhesive, and the second piezoelectric element 6 is bonded to the second metal beam with conductive epoxy adhesive; the piezoelectric element is polarized along the thickness direction of the piezoelectric metal beam.

[0018] Specifically, the metal beam in the opening direction of the E-type cantilever beam structure 13 is connected to the vertical frame 2 of the base through the fixing clamp assembly 4 and fixing bolts; the clamp assembly is provided with a gap for clamping the metal beam; the upper and lower locking nuts are threadedly connected to the clamp, and the clamp 4 is threadedly connected to the vertical frame 2; while the upper and lower locking nuts lock the clamp assembly 4, the metal beam structure 13 is clamped and fixed.

[0019] like Figure 5 As shown, the vertical frames 2 and 12 on both sides of the base are provided with threaded holes of different heights; the energy harvesting device also includes a first fixed magnet 8-3 and a second fixed magnet 8-4. The first fixed magnet 8-3 and the second fixed magnet 8-4 are fixedly connected to the vertical frames 2 and 12 of the base by locking bolts. The fixed magnets are respectively arranged opposite to the first movable magnet 8-1 and the second movable magnet 8-2, and the magnetic poles of the two magnets that are close to each other are the same, forming two pairs of repulsive magnetic couplings.

[0020] Specifically, the base plate 11 is provided with a sliding groove 15 and fixing bolts; the second bracket 14 is slidably disposed in the sliding groove 15, the sliding groove 15 is provided with threaded holes, and the second bracket 14 is locked by locking bolts, and the positions of the first moving magnet 8-1, the second moving magnet 8-2 and the second bracket 14 are adjusted to be aligned.

[0021] Specifically, the right vertical frame 12 is connected to a locking bolt, which is fixed to the base plate slide groove 15. The second fixed magnet 8-4 and the first coil 9 are fixed to the right vertical frame 12 by the locking bolt. The height of the first coil 9 is controlled by the vertical frame 12 so that the user can adjust the positional relationship between the coil 9 and the first moving magnet 8-1.

[0022] Example 2: like Figure 6 As shown, based on Embodiment 1, a fixed magnet can be added to the bottom plate slide groove 15, and a fixed magnet 16 and a fixed magnet 17 can be added to the vertical structure 12 on the right side.

[0023] It should be noted that in the description of this example, the terms "left" and "right," etc., indicate the orientation or positional relationship based on the illustrated orientation or positional relationship, and are only used to simplify the description of this example, and do not specifically refer to orientation and position. The above examples are merely illustrative of the present invention and do not constitute a limitation on the scope of protection of the present invention. Several improvements can be made without departing from the principles described in the present invention, and these improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A two-degree-of-freedom piezoelectric-electromagnetic composite energy harvesting device, characterized in that, The device comprises a base (1), an E-shaped cantilever beam structure (13), a permanent magnet assembly (8), a fixed clamping plate assembly (4), a coil (9), a base fixing clamp (2) and an adjustable clamping device (10); wherein: the base (1) comprises a bottom plate (11) and left and right vertical frames (2, 12) for mounting the E-shaped cantilever beam structure (13) and the permanent magnet assembly (8); the E-shaped cantilever beam structure (13) is composed of a main beam (13-1) and a slave beam (13-2), which are arranged in parallel in the horizontal plane, and the open ends are fixedly connected to the left vertical frame (2) through the fixed clamping plate assembly (4); piezoelectric elements (5, 6, 7) are attached to the main beam and the slave beam respectively, and the piezoelectric elements are polarized along the thickness direction of the metal beam; the free end of the main beam (13-1) is provided with a first moving magnet (8-1), and the free end of the slave beam (13-2) is provided with a second moving magnet (8-2); a first fixed magnet (8-3) and a second fixed magnet (8-4) are respectively mounted on the left and right vertical frames (2, 12), the moving magnets and the fixed magnets are arranged oppositely and have the same magnetic pole, forming two pairs of repulsive magnetic coupling units; the distance between the two pairs of magnetic coupling units can be independently adjusted to control the magnetic coupling strength of the main beam and the slave beam (13-2) respectively, realizing nonlinear potential energy; the coil (9) is mounted on the right vertical frame (12) and arranged opposite to the first moving magnet (8-1), when the cantilever beam vibrates, the moving magnet cuts the magnetic induction lines to generate an induced electromotive force; through the collaborative design of "E-shaped main-slave beam" and "repulsive magnetic coupling", the structure widens the energy capture frequency band, improves the output power and energy conversion efficiency, is compact and adjustable, and is suitable for self-powered occasions in a vibrating environment.

2. The compound energy harvester of claim 1, wherein: The base (1) comprises a left vertical frame (2) and a right vertical frame (12), and different height threaded holes are provided on the two vertical frames for mounting the fixed magnet assembly; the device further comprises a first fixed magnet (8-3) and a second fixed magnet (8-4) which are fixed on the left vertical frame (2) and the right vertical frame (12) through threaded connection respectively; the free ends of the main beam (13-1) and the slave beam (13-2) are respectively provided with a first moving magnet (8-1) and a second moving magnet (8-2), the moving magnets are arranged opposite to the corresponding fixed magnets, and the magnetic pole directions of the ends close to each other are the same, forming two pairs of repulsive magnetic coupling units; the two pairs of repulsive magnetic coupling units act on the end portions of the main beam (13-1) and the slave beam (13-2) respectively, constituting an adjustable nonlinear potential energy field, so as to realize the coupling regulation of the main-slave mode and the bistable energy capture characteristics of the system.

3. The compound energy-capturing device of claim 1, wherein: The adjustable clamping device is composed of a sliding groove (15), a locking nut and an adjustment scale, which can fine-tune the initial position of the right vertical frame (12) after installation, so as to adjust the distance between the first moving magnet (8-1), the second fixed magnet (8-4) and the coil (9) without changing the structure size, thereby adjusting the natural frequency of the system.

4. The compound energy-capturing device of claim 1, wherein: The piezoelectric elements (5, 6, 7) are arranged in a segmented symmetrical manner, the piezoelectric elements (5) are arranged on the main beam (13-1), the piezoelectric elements (7) are arranged on the beam (13-2), the piezoelectric elements are adhered to the surface of the metal beam through conductive epoxy, the electrodes are connected to the energy storage unit after parallel rectification output, so as to improve the total energy conversion efficiency and realize load matching optimization.

5. The compound energy-capturing device of claim 1, wherein: The coil assembly (9) is wound by multiple layers of enameled wire, the coil base is installed in the sliding groove (15) of the base (1) through the movable support (14), the coil position can be fine-tuned in the vertical direction and the axial direction, so as to optimize the magnetic flux cutting effect and the output voltage.

6. The compound energy-capturing device of claim 1, wherein: The permanent magnet assembly (8) is made of neodymium iron boron material, the magnetic pole direction is arranged along the length direction of the cantilever beam; by adjusting the magnet spacing, a monostable, bistable or multi-stable working mode can be formed, so that stable wide frequency response characteristics can be obtained under different vibration amplitude conditions.

7. The compound energy-capturing device of claim 1, wherein: The device can be installed in a low-frequency vibration environment such as a vehicle suspension system, the E-shaped main and slave beams (13-2) are excited to produce coupled vibration through the low-frequency vibration in the environment, energy composite output is realized through piezoelectric and electromagnetic effects, the output voltage is used to drive the sensing node after rectification and stabilization, and self-powered monitoring is realized.

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