A piezoelectric-electromagnetic coupling vibration energy harvesting device with continuously adjustable resonant frequency

Abstract

The present invention relates to a piezoelectric-electromagnetic coupling vibration energy harvesting device with continuously adjustable resonant frequency, comprising an energy harvesting bracket, a piezoelectric cantilever beam, an electromagnetic coil, and a bending piezoelectric transducer. By adjusting the nuts of the upper and lower brackets to change the magnetic moment, the nonlinear magnetic force changes, and the resonant frequency of the vibration energy harvesting device can be continuously adjusted, and the vibration energy of the three parts of the piezoelectric cantilever beam, the electromagnetic coil, and the bending piezoelectric transducer can be synchronously collected. The device receives external excitation, and the vibration is transmitted to the piezoelectric cantilever beam clamped by the clip through the bolt, completing the vibration energy collection of the piezoelectric ceramic at the root of the cantilever beam; the magnet at the end of the piezoelectric cantilever beam moves up and down, changing the magnetic flux inside the coil, generating an induced current, and realizing the partial vibration energy collection of the electromagnetic coil; the magnetic repulsion between the magnet and the magnet on the top of the bending transducer compresses the piezoelectric ceramic inside the bending transducer, completing the partial vibration energy collection of the bending piezoelectric transducer.

Description

Technical Field

[0001] The invention belongs to the field of vibration energy collection, and relates to a piezoelectric-electromagnetic coupling vibration energy collection device with continuously adjustable resonant frequency. Background Art

[0002] Currently, there are three main methods of vibration energy recovery: electrostatic, electromagnetic, and piezoelectric.

[0003] Currently, most designs of vibration energy harvesting devices at home and abroad focus on collecting vibration energy at a single frequency, ignoring the complex frequency components in actual operating environments, resulting in low vibration energy harvesting efficiency and low energy utilization.

[0004] Piezoelectric-electromagnetic coupling vibration energy harvesting devices can improve the collection efficiency of vibration energy and enhance energy utilization. However, the structure of most piezoelectric-electromagnetic coupling vibration energy harvesting devices cannot be changed at any time, and the resonant frequency cannot be adjusted, making them unsuitable for complex and changeable operating conditions. Summary of the Invention

[0005] The present invention addresses the main existing problems of vibration energy harvesting devices: (1) they mainly collect vibration energy at a single frequency; (2) the resonant frequency cannot be adjusted; and (3) the piezoelectric-electromagnetic coupling vibration energy harvesting device does not fully utilize the repulsive force between magnets. Nonlinear magnetic force is introduced to broaden the frequency band of vibration energy harvesting and achieve wide-band energy harvesting. The adjusting nut changes the position of the upper and lower brackets, changes the position of the magnet on the top of the curved piezoelectric transducer, changes the magnetic force between the magnets, and adjusts the resonant frequency of the vibration of the entire device. The present invention sets up a curved piezoelectric transducer, combines electromagnetic and piezoelectric power generation methods, and develops a piezoelectric-electromagnetic coupling vibration energy harvesting device with continuously adjustable resonant frequency. This device realizes the synchronous collection of vibration energy from the piezoelectric cantilever beam, electromagnetic coil, and curved piezoelectric transducer, improves the magnetic force utilization rate of the current piezoelectric-electromagnetic coupling energy harvesting device, and adapts to complex and changeable actual working conditions.

[0006] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0007] A piezoelectric-electromagnetic coupling vibration energy collection device with continuously adjustable resonant frequency, characterized by comprising: an energy collection bracket (1), a piezoelectric cantilever beam (2), an electromagnetic coil (3), and a bending piezoelectric transducer (4).

[0008] The energy collection bracket (1) comprises an upper bracket (11), a bolt (12), a nut (13), and a lower bracket (14). A circular through hole with a diameter of 5 to 10 mm is opened at the center of the lower bracket (14). The energy collection bracket (1) is fixed to the external excitation device by the bolt (12). The upper bracket (11) and the lower bracket (14) are connected and fixed by the bolt (12) and the nut (13).

[0009] The piezoelectric cantilever beam (2) comprises an aluminum substrate (15) and a first piezoelectric ceramic (16). The piezoelectric cantilever beam (2) is clamped and fixed by an aluminum clamping platform (17). The length of the aluminum clamping platform (17) clamping the aluminum substrate (15) is 20-30 mm.

[0010] The electromagnetic coil (3) includes a coil frame (19), a coil (20), and a coil placement table (21). The coil placement table (21) is adhered to the inner surfaces of the upper bracket (11) and the lower bracket (14) by epoxy resin glue. The coil (20) is wound on the coil frame (19), and the coil frame (19) is adhered to the surface of the coil placement table (21) by epoxy resin glue.

[0011] The bending piezoelectric transducer (4) includes a bending clip (24), a bending piezoelectric transducer magnet (22), and a second piezoelectric ceramic (23). The bending clip (24) holds the second piezoelectric ceramic (23) in the middle. The bottom of the bending clip (24) made of 65Mn is adhered to the surfaces of the upper bracket (11) and the lower bracket (14) by epoxy resin glue. The upper and lower parts of the bending piezoelectric transducer (4) are symmetrical.

[0012] Preferably, the bolts (12) pass through circular through holes with a diameter of 5 to 10 mm on both sides of the aluminum clamping platform (17), and the piezoelectric cantilever beam (2) is clamped and fixed by nuts (13).

[0013] Preferably, the first piezoelectric ceramic (16) is adhered to the root of the aluminum substrate (15) with epoxy resin glue, and the piezoelectric cantilever beam magnet (18) is adhered to the end position of the piezoelectric cantilever beam (2) with epoxy resin glue, and the piezoelectric cantilever beam magnet (18) is symmetrical in the upper and lower parts.

[0014] Preferably, a circular hole is provided at the center of the coil placement platform (21), the curved piezoelectric transducer magnet (22) passes through the circular hole of the coil placement platform (21), the curved piezoelectric transducer magnet (22) is placed inside the coil frame (19), the coil frame (19) and the curved piezoelectric transducer magnet (22) are coaxial, and the electromagnetic coil (3) is symmetrical up and down.

[0015] Preferably, the angle between the bent clip (24) and the second piezoelectric ceramic (23) ranges from 15 to 25 degrees.

[0016] Preferably, the diameter of the curved piezoelectric transducer magnet (22) is equal to the width of the second piezoelectric ceramic (23) and the curved clip (24), and the curved piezoelectric transducer magnet (22) is coaxial with the piezoelectric cantilever beam magnet (18).

[0017] The piezoelectric-electromagnetic coupling vibration energy collection device with continuously adjustable resonant frequency can synchronously collect vibration energy from three parts: a piezoelectric cantilever beam (2), an electromagnetic coil (3), and a bending piezoelectric transducer (4).

[0018] Preferably, the magnetic distance between the piezoelectric cantilever beam magnet (18) and the bending piezoelectric transducer magnet (22) is continuously adjusted by the upper bracket (11), the lower bracket (14), and the nut (13).

[0019] Preferably, the piezoelectric cantilever beam (2) receives vibration via an aluminum clamping platform (17), and the piezoelectric cantilever beam magnet (18) synchronously drives the electromagnetic coil (3) and the bending piezoelectric transducer (4) to collect vibration energy.

[0020] Preferably, the piezoelectric cantilever beam magnet (18), the electromagnetic coil (3), and the bending piezoelectric transducer (4) are at the same vertical position.

[0021] The working principle of the present invention is as follows: Adjusting the nut 13 changes the position of the bracket, thereby changing the magnetic moment, achieving continuously adjustable resonant frequency of the vibration energy harvesting device. The lower bracket 14 receives external excitation, and vibration is transmitted to the aluminum clamping platform 17 via the bolt 12. The vibration on the aluminum clamping platform 17 is then transmitted to the piezoelectric cantilever beam 2, causing the piezoelectric cantilever beam 2 to oscillate up and down. The first piezoelectric ceramic 16 at the base of the cantilever beam is subjected to compressive and shear forces. Due to the positive piezoelectric effect, the charge within the first piezoelectric ceramic 16 shifts, generating a voltage across the external load of the first piezoelectric ceramic 16. As the piezoelectric cantilever beam 2 oscillates up and down, the piezoelectric cantilever magnet 18 moves up and down, causing the magnetic flux within the upper and lower coils 20 to change, generating an induced current within the coils 20. The magnetic force of the piezoelectric cantilever magnet 18 acts on the curved piezoelectric transducer magnet 22 at the top of the curved piezoelectric transducer 4, compressing the second piezoelectric ceramic 23 in the curved piezoelectric transducer 4, causing charge shift and generating a voltage across the external load of the second piezoelectric ceramic 23.

[0022] The beneficial effects of the present invention are concentrated in the following aspects:

[0023] 1. The present invention changes the magnetic moment between the piezoelectric cantilever beam magnet and the bent piezoelectric transducer magnet by adjusting the nuts of the upper and lower brackets, thereby changing the nonlinear magnetic force. This enables continuous adjustment of the resonant frequency of the piezoelectric-electromagnetic coupling vibration energy harvesting device and achieves efficient energy harvesting under complex operating conditions.

[0024] 2. The present invention sets a curved piezoelectric transducer in the magnetic part, which improves the utilization rate of the magnetic force in the electromagnetic part of the piezoelectric-electromagnetic coupling vibration energy collection device, and simultaneously realizes the collection of vibration energy of three parts: the piezoelectric cantilever beam, the electromagnetic coil, and the curved piezoelectric transducer, thereby improving the vibration energy collection effect of the device and collecting vibration energy to the greatest extent.

[0025] 3. The piezoelectric cantilever beam, electromagnetic coil and bending piezoelectric transducer in the present invention have a stable structure, are easy to assemble and manufacture, and are suitable for working under low-frequency and large-amplitude vibration conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of the overall structure of a piezoelectric-electromagnetic hybrid vibration energy harvesting device with continuously adjustable resonant frequency.

[0027] Figure 2 Schematic diagram of the energy harvesting bracket of the piezoelectric-electromagnetic hybrid vibration energy harvesting device with continuously adjustable resonant frequency.

[0028] Figure 3 A 45-degree side view of the overall structure of a piezoelectric-electromagnetic hybrid vibration energy harvesting device with continuously adjustable resonant frequency.

[0029] Figure 4 Schematic diagram of the piezoelectric cantilever beam structure and the aluminum clamping platform.

[0030] Figure 5 Schematic diagram of the position relationship between the piezoelectric cantilever beam and the electromagnetic coil.

[0031] . Figure 6 Schematic diagram of the position relationship between the piezoelectric cantilever beam and the bending piezoelectric transducer.

[0032] Figure 7 A top view of the electromagnetic coil structure.

[0033] Figure 8 Schematic diagram of the positional relationship between the coil skeleton and the bending piezoelectric transducer.

[0034] Figure 9 Schematic diagram of the bending piezoelectric transducer structure.

[0035] In the figure, 1. Energy collection bracket; 2. Piezoelectric cantilever beam; 3. Electromagnetic coil; 4. Bending piezoelectric transducer; 11. Upper bracket; 12. Bolt; 13. Nut; 14. Lower bracket; 15. Aluminum substrate; 16. First piezoelectric ceramic; 17. Aluminum clamping platform; 18. Piezoelectric cantilever beam magnet; 19. Coil frame; 20. Coil; 21. Coil placement platform; 22. Bending piezoelectric transducer magnet; 23. Second piezoelectric ceramic; 24. Bending clip. DETAILED DESCRIPTION

[0036] The following describes specific embodiments of the present invention in detail. To avoid unnecessary detail, well-known structures or functions are not described in detail in the following examples. Approximate language used in the following examples can be used to express quantitative information, indicating that a certain amount of variation is allowed without changing the basic function. Unless otherwise defined, technical and scientific terms used in the following examples have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0037] The present invention will be described in further detail below with reference to the embodiments and accompanying drawings. Figure 1 The figure shows the overall structure of a piezoelectric-electromagnetic coupling vibration energy harvesting device with continuously adjustable resonant frequency, including an energy harvesting bracket 1, a piezoelectric cantilever beam 2, an electromagnetic coil 3, and a bending piezoelectric transducer 4.

[0038] Figure 2 The energy collection bracket of the piezoelectric-electromagnetic hybrid vibration energy harvesting device with continuously adjustable resonant frequency shown in the figure includes an upper bracket 11, a bolt 12, a nut 13, and a lower bracket 14. The upper bracket 11 and the lower bracket 14 are passed through by the bolt 12 and fixed in vertical position by the nut 13. The lower bracket 14 can be fixed at a position where the working part excites intense vibration by the bolt 12 and the nut 13.

[0039] Figure 4 The piezoelectric cantilever beam structure shown in the figure is mated with an aluminum clamping platform. The piezoelectric cantilever beam 2 includes a first piezoelectric ceramic 16, an aluminum substrate 15, and a piezoelectric cantilever beam magnet 18. The aluminum substrate 15 is clamped and fixed in the middle by an aluminum clamping platform 17. The first piezoelectric ceramic 16 is glued to the base of the piezoelectric cantilever beam 2 with epoxy resin, close to the aluminum clamping platform 17. The piezoelectric cantilever beam magnet 18 is glued to the end of the piezoelectric cantilever beam 2.

[0040] Figure 5 The diagram shows the relationship between the piezoelectric cantilever beam and the electromagnetic coil, including the coil bobbin 19, coil 20, and coil support 21. The coil 20 is evenly wound around the coil bobbin 19, which is placed on the coil support 21 to ensure that the coil bobbin 19 and the piezoelectric cantilever beam magnet 18 are coaxial.

[0041] Figure 8 The figure shows the positional relationship between the coil skeleton and the bending piezoelectric transducer. The bending piezoelectric transducer 4 includes a bending piezoelectric transducer magnet 22, a second piezoelectric ceramic 23, and a bending clip 24. The diameter of the bending piezoelectric transducer magnet 22, the width of the second piezoelectric ceramic 23, and the width of the bending clip 24 are equal.

[0042] The curved piezoelectric transducer magnet 22 is glued to the top of the curved clip 24 with epoxy resin glue, and the second piezoelectric ceramic 23 is glued between the two curved clips 24 with epoxy resin glue to ensure that the center of the curved piezoelectric transducer magnet 22 coincides with the middle position of the top of the curved clip 24. The curved clip 24 is glued to the surface of the upper bracket 11 and the lower bracket 14.

[0043] The working process of the piezoelectric-electromagnetic coupling vibration energy harvesting device with continuously adjustable resonant frequency:

[0044] When the machine is operating under variable working conditions, the vibration characteristics are analyzed to obtain the frequency domain data of the vibration. According to the obtained frequency domain data, the nut 13 is screwed to adjust the position of the upper bracket 11 and the lower bracket 14, the magnetic distance is changed, and energy collection begins; the lower bracket 14 is fixed to the surface of the position where the working part of the machine vibrates violently by the bolt 12 and the nut 13, receives the vertical vibration transmitted by the working part, and transmits it to the bolt 12. The aluminum clamping platform 17 is nested on the bolt 12, and the vibration is transmitted to the piezoelectric cantilever beam 2 by the aluminum clamping platform 17. The aluminum substrate 15 generates vibration, and the end moves up and down. The first piezoelectric ceramic 1 at the root of the piezoelectric cantilever beam 2 6 is subjected to squeezing and shearing forces, and due to the positive piezoelectric effect, the internal charges move and generate voltage; when the end of the aluminum substrate 15 moves up and down, the piezoelectric cantilever beam magnet 18 attached to the end moves up and down, causing the magnetic flux inside the coil 20 to change, and current is generated inside the coil to generate electrical energy; at the same time, the piezoelectric cantilever beam magnet 18 moves up and down, and the bending piezoelectric transducer magnet 22 in the bending piezoelectric transducer 4 is acted upon by the magnetic force from the piezoelectric cantilever beam magnet 18, exerting an squeezing force on the bending clip 24, and the bending clip 24 acts evenly on the second piezoelectric ceramic 23, and the second piezoelectric ceramic 23 generates voltage in the same principle as before.

[0045] The embodiments described are only preferred implementations of the present invention, but the present invention is not limited to the above implementations. Any obvious improvements, replacements or modifications that can be made by any technician familiar with this technical field fall within the scope of protection of the present invention.

Claims

1. A piezoelectric-electromagnetic coupling vibration energy harvesting device with continuously adjustable resonant frequency, characterized in that: include: An energy collection bracket (1), a piezoelectric cantilever beam (2), an electromagnetic coil (3), and a bending piezoelectric transducer (4); the energy collection bracket (1) includes an upper bracket (11), a bolt (12), a nut (13), and a lower bracket (14); a circular through hole with a diameter of 5 to 10 mm is opened in the center of the lower bracket (14); the energy collection bracket (1) is fixed to an external excitation device by a bolt (12); the upper bracket (11) and the lower bracket (14) are connected and fixed by bolts (12) and nuts (13); the piezoelectric cantilever beam (2) includes an aluminum substrate (15), a first piezoelectric The piezoelectric cantilever beam (2) is fixed by an aluminum clamping platform (17), and the length of the aluminum clamping platform (17) clamping the aluminum substrate (15) is 20 to 30 mm; the electromagnetic coil (3) includes a coil frame (19), a coil (20), and a coil placement platform (21), and the coil placement platform (21) is adhered to the inner surface of the upper bracket (11) and the lower bracket (14) by epoxy resin glue, and the coil (20) is wound on the coil frame (19), and the coil frame (19) is adhered to the surface of the coil placement platform (21) by epoxy resin glue; bending pressure The electric transducer (4) includes a bending clip (24), a bending piezoelectric transducer magnet (22), and a second piezoelectric ceramic (23). The bending clip (24) clamps the second piezoelectric ceramic (23) in the middle. The bottom of the bending clip (24) made of 65Mn is adhered to the surface of the upper bracket (11) and the lower bracket (14) by epoxy resin glue. The upper and lower parts of the bending piezoelectric transducer (4) are symmetrical. The bolt (12) passes through the aluminum clamping platform (17) on both sides and has a circular through hole with a diameter of 5 to 10 mm. The piezoelectric cantilever beam (2) is fixedly clamped by a nut (13); the first The piezoelectric ceramic (16) is glued to the root of the aluminum substrate (15) with epoxy resin glue, and the piezoelectric cantilever beam magnet (18) is glued to the end position of the piezoelectric cantilever beam (2) with epoxy resin glue, and the piezoelectric cantilever beam magnet (18) is symmetrical up and down; a circular hole is provided at the center position of the coil placement platform (21), and the curved piezoelectric transducer magnet (22) passes through the circular hole of the coil placement platform (21), and the curved piezoelectric transducer magnet (22) is placed inside the coil frame (19), and the coil frame (19) and the curved piezoelectric transducer magnet (22) are coaxial, and the electromagnetic coil (3) is symmetrical up and down.

2. The piezoelectric-electromagnetic coupling vibration energy harvesting device with continuously adjustable resonant frequency according to claim 1, characterized in that: The angle between the bent clip (24) and the second piezoelectric ceramic (23) is in the range of 15-25 degrees, the diameter of the bent piezoelectric transducer magnet (22) is equal to the width of the second piezoelectric ceramic (23) and the bent clip (24), and the bent piezoelectric transducer magnet (22) is coaxial with the piezoelectric cantilever beam magnet (18).

3. The piezoelectric-electromagnetic coupling vibration energy harvesting device with continuously adjustable resonant frequency according to claim 1, characterized in that: The vibration energy of the piezoelectric cantilever beam (2), the electromagnetic coil (3), and the bending piezoelectric transducer (4) is collected synchronously. The magnetic distance between the piezoelectric cantilever beam magnet (18) and the bending piezoelectric transducer magnet (22) is continuously adjusted by the upper bracket (11), the lower bracket (14), and the nut (13). The piezoelectric cantilever beam (2) receives vibration through the aluminum clamping table (17). The piezoelectric cantilever beam magnet (18) synchronously drives the electromagnetic coil (3) and the bending piezoelectric transducer (4) to collect vibration energy. The piezoelectric cantilever beam magnet (18) and the electromagnetic coil (3) and the bending piezoelectric transducer (4) are at the same vertical position.

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