Low frequency bistable piezoelectric-electromagnetic hybrid energy harvester

Abstract

This invention discloses a low-frequency bistable piezoelectric-electromagnetic hybrid energy harvester, comprising a base, a piezoelectric beam movably connected to the base, the piezoelectric beam being vertical and movable horizontally; a piezoelectric ceramic is fixed on the piezoelectric beam, and a rigid connecting rod is hinged to the end of the piezoelectric beam away from the base, the rigid connecting rod being hinged to a mass block, and a connecting rod being fixed to the bottom of the mass block; a vertically oriented sleeve is also fixed on the base, the sleeve being closed at both ends, and annular magnets are respectively installed at both ends inside the sleeve; the connecting rod enters the sleeve vertically through the upper end of the sleeve, and an electromagnet is fixed to the top of the connecting rod; a coil is wound around the outer wall of the sleeve. A bistable structure is formed by the piezoelectric beam and the mass block hinged by the connecting rod; the bending of the piezoelectric beam at both ends achieves the positive piezoelectric effect, converting the deformation energy stored in the piezoelectric element into electrical energy; the vertical vibration of the mass block drives the electromagnet to vibrate, changing the magnetic flux of the coil, converting mechanical energy into electrical energy, thus realizing electromagnetic power generation.

Description

Technical Field

[0001] The invention belongs to the technical field of energy capture, and relates to a low-frequency bistable piezoelectric-electromagnetic hybrid energy capture device. Background Art

[0002] In recent years, energy capture has become one of the hot technologies that attracts the attention of both academia and industry. Among them, vibration energy capture is a widely studied low-power electronic device autonomous power supply technology, which provides a solution to the problem of long-term and reliable power supply for future wireless sensor network technology and Internet of Things technology. The battery life of traditional sensor systems is limited, replacement is difficult, and the cost is high. In addition, used batteries also cause environmental pollution.

[0003] The basic principle of vibration energy capture is to collect and utilize the energy contained in the displacement or deformation of an object caused by external movement and convert it into electrical energy. According to the capture mechanism, it is mainly divided into three categories: piezoelectric, electrostatic and electromagnetic induction. Piezoelectric energy capture uses the positive piezoelectric effect of piezoelectric materials to convert the deformation energy of piezoelectric materials into electrical energy; the basic principle of electrostatic vibration energy capture is to generate electrical energy through changes in capacitance caused by environmental vibration; the basic principle of electromagnetic vibration energy capture is to use Faraday's electromagnetic induction theorem, that is, an electric field is generated when the magnetic flux changes.

[0004] In order to improve the efficiency of vibration energy capture, researchers have conducted extensive innovations and experiments. Traditional linear vibration energy capture can only capture energy in the resonance peak area, and the frequency band is narrow. Most vibrations in the natural environment are random, and how to capture energy in a wider working frequency band has become one of the research hotspots. By introducing nonlinear structures, the frequency band can be widened to achieve a wider working frequency band. The introduction of multi-stable structures allows the collector to produce nonlinear vibration characteristics such as monostable, bistable and tristable states, which can also achieve the purpose of improving the output performance of the energy harvester. Summary of the invention

[0005] The purpose of the present invention is to provide a low-frequency bistable piezoelectric-electromagnetic hybrid energy harvester, which solves the problem in the prior art that energy cannot be captured in a wider working frequency band.

[0006] The technical solution adopted by the present invention is a low-frequency bistable piezoelectric-electromagnetic hybrid energy harvester, comprising a base, on which a piezoelectric beam is movably connected, the piezoelectric beam is in a vertical direction and can move in a horizontal direction; piezoelectric ceramics are fixed on the piezoelectric beam, one end of the piezoelectric beam away from the base is hinged with a rigid connecting rod, the rigid connecting rod is hinged to a mass block, and a connecting rod is fixed to the bottom of the mass block;

[0007] A sleeve in a vertical direction is also fixed on the base, with both ends of the sleeve closed and annular magnets respectively arranged at both ends inside the sleeve; a connecting rod vertically enters the interior of the sleeve through the upper end of the sleeve, and an electromagnet is fixed to the top of the connecting rod; a coil is wound around the outer wall of the sleeve.

[0008] The present invention is also characterized in that:

[0009] A perforated slide groove is provided on the base, a slider is fixed on the piezoelectric beam through a double-headed screw, and the slider is embedded in the perforated slide groove.

[0010] The base is convex, a groove is arranged in the middle of the convexity, a sleeve bottom support is fixed in the groove, and a sleeve is fixed on the sleeve bottom support.

[0011] The piezoelectric ceramic is arranged at the bottom end of the piezoelectric beam.

[0012] A revolute pair is fixed to one end of the piezoelectric beam away from the base, and the piezoelectric beam is hinged to the rigid connecting rod through the revolute pair.

[0013] A plurality of air holes are provided on the sleeve.

[0014] The upper end of the sleeve is closed by the sleeve top support, and the annular magnet on the sleeve top is fixed to the sleeve top support by glue; the lower end of the sleeve is closed by the sleeve bottom support, and a fixing flange is provided below the base relative to the groove, and a bolt rod is threadedly connected to the fixing flange, and the top end of the bolt rod is glued to the annular magnet at the bottom of the sleeve.

[0015] A linear bearing is fixed on the top support of the sleeve, and the connecting rod is glued to the mass block through the linear bearing.

[0016] Positioning holes are provided at the upper end and the lower end of the sleeve, and the sleeve top support and the sleeve bottom support are positioned through the positioning holes.

[0017] The present invention forms a bistable structure through a connecting rod hinge between a piezoelectric beam and a mass block, realizes a positive piezoelectric effect through the bending of the piezoelectric beams at both ends, and converts the deformation energy stored in the piezoelectric sheet into electrical energy; the vertical vibration of the mass block drives the electromagnet to vibrate, the magnetic flux of the coil changes, and the mechanical energy is converted into electrical energy to realize electromagnetic power generation. Through the nonlinear force of the magnetic suspension component and the piezoelectric energy capture component, energy capture is achieved in a wider working frequency band, and quasi-zero stiffness is formed, resonance is generated at low frequency, and the effect of vibration reduction is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the low-frequency bistable piezoelectric-electromagnetic hybrid energy harvester of the present invention;

[0019] Figure 2 It is a front view schematic diagram of the low-frequency bistable piezoelectric-electromagnetic hybrid energy harvester of the present invention;

[0020] Figure 3 It is a schematic diagram of the sleeve arrangement of the low-frequency bistable piezoelectric-electromagnetic hybrid energy harvester of the present invention;

[0021] Figure 4 It is a cross-sectional view of the sleeve arrangement of the low-frequency bistable piezoelectric-electromagnetic hybrid energy harvester of the present invention.

[0022] In the figure, 1. base, 2. piezoelectric beam, 3. piezoelectric ceramic, 4. rigid connecting rod, 5. mass block, 6. connecting rod, 7. sleeve, 8. annular magnet, 9. electromagnet, 10. coil, 11. perforated slide groove, 12. slider, 13. bottom support of sleeve, 14. revolute pair, 15. air hole, 16. top support of sleeve, 17. fixing flange, 18. bolt rod, 19. linear bearing, 20. positioning hole. DETAILED DESCRIPTION

[0023] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] The low-frequency bistable piezoelectric-electromagnetic hybrid energy harvester of the present invention is as follows: Figure 1 and Figure 2 As shown, it includes a base 1, which is convex with a groove in the middle of the convexity, fixed to the bottom support 13 of the sleeve, and has perforated slide grooves 11 on the left and right sides, and the perforated slide grooves 11 and the slider 12 are fixed by double-headed screws; the piezoelectric beam 2 is attached with a piezoelectric ceramic 3 and connected to the extension hole of the slider 12; the piezoelectric beam 2 is hinged and fixed to the rotating pair 14 by screws, and the rotating pair 14 is connected to the mass block 5 by a rigid connecting rod 4; the base 1, the piezoelectric ceramic 3 and the piezoelectric beam 2 together constitute the piezoelectric energy capture component of the present invention.

[0025] like Figure 3 and Figure 4 As shown, a sleeve 7 in a vertical direction is fixed on the base 1, and both ends of the sleeve 7 are closed. An annular magnet 8 is respectively arranged at both ends of the sleeve 7; the connecting rod 6 enters the sleeve 7 vertically through the upper end of the sleeve 7, and an electromagnet 9 is fixed to the top of the connecting rod 6; a coil 10 is wound around the outer wall of the sleeve 7. The upper end of the sleeve 7 is closed by the sleeve top support 16, and the annular magnet 8 at the top of the sleeve 7 is fixed to the sleeve top support 16 by glue; the lower end of the sleeve 7 is closed by the sleeve bottom support 13, and a fixing flange 17 is arranged below the base 1 relative to the groove, and the fixing flange 17 is threadedly connected with a bolt rod 18, and the top of the bolt rod 18 is glued to the annular magnet 8 at the bottom of the sleeve 7. A linear bearing 19 is fixed on the sleeve top support 16, and the connecting rod 6 is glued to the mass block 5 through the linear bearing 19. Positioning holes 20 are opened at the upper end and the lower end of the sleeve 7, and the sleeve top support 16 and the sleeve bottom support 13 are positioned through the positioning holes 20. The electromagnet 9, the annular magnet 8 and the coil 10 together constitute the magnetic suspension assembly of the present invention.

[0026] During operation, the base 1 is installed on a vibration source such as a building structure or a mechanical structure. The base 1 drives the electromagnet 9 to vibrate under the excitation of an external vibration source. The electromagnet 9 transmits the vibration to the mass block 5 through the connecting rod 6. The mass block 5 drives the piezoelectric beam 2 to undergo buckling vibration through the rigid connecting rod 4.

[0027] like Figure 2 As shown, when the piezoelectric beam 2 undergoes buckling vibration, the piezoelectric ceramic 3 attached to the piezoelectric beam 2 generates a positive piezoelectric effect, converting the vibration energy into electrical energy.

[0028] like Figure 3 As shown, the electromagnet 9 vibrates, and through the interaction with the annular magnets 8 at both ends of the sleeve 7, the magnetic flux of the coil 10 changes, converting the mechanical energy of the vibration into electrical energy. The existence of the air hole 15 makes the pressure inside and outside the sleeve 7 equal, avoiding the atmospheric repulsion generated when the electromagnet 9 vibrates.

[0029] The present invention proposes a low-frequency bistable piezoelectric-electromagnetic hybrid energy harvester, which completes energy capture through the joint action of a piezoelectric energy harvesting component and a magnetic suspension component. The magnetic coupling between the middle electromagnet 9 and the annular magnets 8 at both ends of the sleeve 7 introduces a nonlinear force, thereby increasing the working bandwidth of the device. By controlling the distance between the middle electromagnet 9 and the annular magnets 8 at both ends of the sleeve 7, the size of the nonlinear force can be adjusted, so that the system can cross the potential barrier to reach a bistable state and widen the bandwidth. A bistable structure can be formed by nonlinear force, which has high energy capture efficiency, a wide working frequency band, and a certain vibration isolation effect, and can replace traditional chemical batteries to power low-power microelectronic devices.

Claims

1. A low-frequency bistable piezoelectric-electromagnetic hybrid energy harvester, characterized in that: The invention comprises a base (1), a piezoelectric beam (2) being movably connected to the base (1), the piezoelectric beam (2) being in a vertical direction and being movable in a horizontal direction; a piezoelectric ceramic (3) being fixed to the piezoelectric beam (2), an end of the piezoelectric beam (2) away from the base (1) being hinged to a rigid connecting rod (4), the rigid connecting rod (4) being hinged to a mass block (5), and a connecting rod (6) being fixed to the bottom of the mass block (5); A sleeve (7) in a vertical direction is also fixed on the base (1), the sleeve (7) is provided with a plurality of air holes (15), the two ends of the sleeve (7) are closed, and annular magnets (8) are respectively arranged at the two ends of the sleeve (7); the connecting rod (6) vertically enters the interior of the sleeve (7) through the upper end of the sleeve (7), and the top of the connecting rod (6) is fixedly connected to an electromagnet (9); a coil (10) is wound around the outer wall of the sleeve (7); the upper end of the sleeve (7) is closed by a sleeve top support (16), and the annular magnet (8) at the top of the sleeve (7) is fixed to the sleeve top support (16) by glue; the lower end of the sleeve (7) is closed by a sleeve bottom support (13), and a fixing flange (17) is arranged below the base (1) relative to the groove, and a bolt rod (18) is threadedly connected to the fixing flange (17), and the top end of the bolt rod (18) is glued to the annular magnet (8) at the bottom of the sleeve (7).

2. The low-frequency bistable piezoelectric-electromagnetic hybrid energy harvester according to claim 1, characterized in that: The base (1) is provided with a perforated slide groove (11), and a slider (12) is fixed to the piezoelectric beam via a double-headed screw, and the slider (12) is inserted into the perforated slide groove (11).

3. The low-frequency bistable piezoelectric-electromagnetic hybrid energy harvester according to claim 1, characterized in that: The base (1) is convex, with a groove in the middle of the convexity, a sleeve bottom support (13) is fixed in the groove, and a sleeve (7) is fixed on the sleeve bottom support (13).

4. The low-frequency bistable piezoelectric-electromagnetic hybrid energy harvester according to claim 1, characterized in that: The piezoelectric ceramic (3) is arranged at the bottom end of the piezoelectric beam (2).

5. The low-frequency bistable piezoelectric-electromagnetic hybrid energy harvester according to claim 1, characterized in that: A revolving pair (14) is fixed to one end of the piezoelectric beam (2) away from the base (1), and the piezoelectric beam (2) is hinged to the rigid connecting rod (4) via the revolving pair (14).

6. The low-frequency bistable piezoelectric-electromagnetic hybrid energy harvester according to claim 1, characterized in that: A linear bearing (19) is fixed on the sleeve top support (16), and the connecting rod (6) is glued to the mass block (5) via the linear bearing (19).

7. The low-frequency bistable piezoelectric-electromagnetic hybrid energy harvester according to claim 1, characterized in that: The upper end of the sleeve (7) and the lower end of the sleeve (7) are both provided with positioning holes (20), and the sleeve top support (16) and the sleeve bottom support (13) are positioned through the positioning holes (20).

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