A multi-resonant piezoelectric energy harvester with up-conversion

Abstract

The present invention relates to a multi-resonance piezoelectric energy harvester with frequency up-conversion, including a piezoelectric energy harvesting module, a power transmission module and a cover plate, wherein: the piezoelectric energy harvesting module has a cantilever substrate and a piezoelectric sheet; the power transmission module has a rotatably arranged paddle for toggling the suspended end of the cantilever substrate, a gear coaxially arranged with the paddle and acting synchronously, a rack meshing with the gear, a slide groove for guiding the movement of the rack, and a first spring connected between the rack and the slide groove; the cover plate is used to receive external excitation, and the cover plate can act on the rack along the length direction of the slide groove through a transmission column, and a second spring for resetting the cover plate is arranged between the cover plate and the slide groove. Compared with the prior art, the present invention converts the low-frequency input of the outside world into the high-frequency vibration of the cantilever beam of the piezoelectric energy harvesting module, and the piezoelectric energy harvesting module is subjected to multiple excitations, which improves the energy harvesting efficiency and increases the electric energy output.

Description

Technical Field

[0001] The invention relates to the field of energy collection, and in particular to a multi-resonance piezoelectric energy harvester with up-frequency conversion. Background Art

[0002] With the development of low-energy, low-power, and independently working systems such as micro-mechanical technology, embedded devices, and wireless sensor networks, the demand for independent power supply is becoming more and more urgent. Nowadays, most devices are still powered by traditional batteries, which have a series of problems such as short life and frequent replacement. In order to solve this problem, people have conducted long-term research on converting energy in the environment into electrical energy. Therefore, energy harvesting technology has become one of the hot topics in today's research.

[0003] Energy harvesting is a technology that converts the energy in the surrounding environment into electrical energy and stores it in energy storage devices. Its energy sources can include available but unused energy in nature, mainly including thermal energy, sound energy, kinetic energy, light energy, tidal energy, wind energy, etc. Vibration is ubiquitous in the living environment. When cars, trains, subways, airplanes and other equipment are running, they will generate vibrations. Therefore, mechanical vibration energy is a ubiquitous energy source. Therefore, the current research on energy harvesters is mainly focused on the aspect of mechanical vibration energy harvesting.

[0004] Mechanical vibration energy harvesting mainly uses vibration energy harvesters to convert mechanical energy in the environment into electrical energy. Vibration energy harvesters are divided into: electromagnetic, electrostatic, piezoelectric and magnetostrictive. Piezoelectric energy harvesters have many advantages such as simple structure, high energy density, no electromagnetic interference, small size and low cost. Therefore, piezoelectric energy harvesters are the most widely studied. However, the existing piezoelectric energy harvesters have limited application scope, small application value and poor practicality. Summary of the invention

[0005] The applicant found that existing piezoelectric energy harvesters have problems such as difficulty in matching the resonant frequency with the ambient vibration frequency, low ambient vibration energy utilization and low conversion efficiency, which leads to their limited application scope, small application value and poor practicality.

[0006] The purpose of the present invention is to provide a multi-resonance piezoelectric energy harvester with frequency up-conversion in order to overcome the defects of the prior art.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] A multi-resonant piezoelectric energy harvester with up-conversion, comprising:

[0009] The piezoelectric energy harvesting module comprises a cantilever substrate and a piezoelectric sheet arranged along the length direction of the cantilever substrate, and a power transmission module comprises a rotatably arranged paddle for moving the suspended end of the cantilever substrate, a gear coaxially arranged with the paddle and acting synchronously, a rack meshing with the gear, a slide groove for guiding the movement of the rack, and a first spring connected between the rack and the slide groove.

[0010] The cover plate is used to receive external excitation, and the cover plate can act on the rack along the length direction of the slide slot through the transmission column. A second spring for returning the cover plate is arranged between the cover plate and the slide slot.

[0011] Preferably, a vertical plate is further included, one end of the cantilever substrate is a suspended end, and the other end is a fixed end, and the fixed end is fixed to the vertical plate through a clamping plate.

[0012] Preferably, the power transmission module further comprises a rotating shaft, a bearing and a bearing seat, the paddle and the gear are passed through the rotating shaft, and both ends of the rotating shaft are rotatably connected to the bearing seat via the bearing.

[0013] Preferably, it also includes a base for supporting the slide groove, the bearing seat and the vertical plate.

[0014] Preferably, the cantilever substrate is arranged horizontally, and two piezoelectric sheets are provided, respectively located on the upper and lower surfaces of the cantilever substrate.

[0015] Preferably, the slide groove is a vertical slide groove, the cover plate covers the vertical plate and the slide groove, and the second spring is also arranged between the vertical plate and the cover plate.

[0016] Preferably, the transmission column is a vertical column, the top end of the vertical column is connected to the cover plate, the bottom end of the vertical column passes through the top of the slide slot, extends into the slide slot, and can act on the top end of the rack.

[0017] Preferably, the first spring is a tension spring, which is arranged between the top of the slide groove and the top of the rack, and the second spring is a compression spring.

[0018] Preferably, there are two gears, which are located on both sides of the paddle, each gear is meshed with a rack, each rack is arranged in two parallel sliding grooves, and a first spring is provided between each rack and the sliding groove.

[0019] The up-conversion in the present invention refers to the conversion of low-frequency vibrations of external excitation into high-frequency vibrations of the piezoelectric energy harvesting module; multi-resonance refers to the continuous back-and-forth rotation of the piezoelectric energy harvesting module, which stimulates the piezoelectric energy harvesting module to resonate multiple times. Specifically, when the power transmission module is stimulated by the cover plate excited by the external excitation, the first spring (taking the tension spring as an example) connected to the rack is stretched, thereby converting the external excitation energy into elastic potential energy. After the external excitation disappears, the first spring will drive the rack to perform resonant motion together. After the rack resonates, it is transmitted to the gear meshing with it, driving the coaxially arranged gear and paddle to rotate back and forth continuously. The angle of the paddle rotating back and forth is less than 180o, and the back-and-forth rotating paddle continuously excites the piezoelectric energy harvesting module. The piezoelectric energy harvesting module is stimulated by the paddle and generates self-resonance, thereby converting the vibration energy into electrical energy.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) The power transmission module used in the multi-resonant piezoelectric energy harvester with frequency up-conversion proposed in the present invention can convert the energy of external excitation into the elastic potential energy of the spring and temporarily store the energy. After the external excitation disappears, the spring will drive the rack to perform resonant motion together.

[0022] (2) The resonant motion of the rack in the present invention causes the gear meshing with it and the paddle coaxial with the gear to rotate back and forth continuously, thereby repeatedly exciting the piezoelectric energy harvesting module to produce resonance and convert energy into electrical energy.

[0023] (3) The present invention converts low-frequency input from the outside into high-frequency vibration of the cantilever beam of the piezoelectric energy harvesting module. In addition, the piezoelectric energy harvesting module is subjected to multiple excitations, which improves the energy harvesting efficiency and increases the electrical energy output. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of the present invention;

[0025] Figure 2 It is a schematic diagram of the main structure of the present invention;

[0026] Figure 3 It is an exploded schematic diagram of the power transmission module of the present invention;

[0027] Figure 4 Schematic diagram of the explosion of the piezoelectric energy harvesting module of the present invention.

[0028] In the figure, 1 is a cover plate, 2 is a transmission column, 3 is a second spring, 4 is a power transmission module, 41 is a slide groove, 42 is a first spring, 43 is a rack, 44 is a gear, 45 is a paddle, 46 is a rotating shaft, 47 is a bearing, 48 is a bearing seat, 5 is a piezoelectric energy harvesting module, 51 is a piezoelectric sheet, 52 is a cantilever substrate, 6 is a vertical plate, and 7 is a base. DETAILED DESCRIPTION

[0029] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] Example 1

[0031] A multi-resonant piezoelectric energy harvester with up-conversion, such as Figures 1 to 4 As shown, it includes a piezoelectric energy collection module 5, a power transmission module 4 and a cover plate 1, wherein:

[0032] The piezoelectric energy harvesting module 5 has a cantilever substrate 52 and a piezoelectric sheet 51 arranged along the length direction of the cantilever substrate 52; the power transmission module 4 has a rotatable paddle 45 for moving the suspended end of the cantilever substrate 52, a gear 44 coaxially arranged with the paddle 45 and acting synchronously, a rack 43 meshing with the gear 44, a slide groove 41 for guiding the movement of the rack 43, and a first spring 42 connected between the rack 43 and the slide groove 41; the cover plate 1 is used to receive external excitation, and the cover plate 1 can apply the external excitation to the rack 43 along the length direction of the slide groove 41 through the transmission column 2, and a second spring 3 for resetting the cover plate 1 is arranged between the cover plate 1 and the slide groove 41.

[0033] Preferably, the multi-resonant piezoelectric energy harvester with up-conversion further comprises a vertical plate 6, one end of the cantilever substrate 52 is a suspension end, and the other end is a fixed end, and the fixed end is fixed to the vertical plate 6 through a clamping plate 53. It is further preferred that the cantilever substrate 52 is arranged horizontally, and two piezoelectric sheets 51 are provided, which are respectively located on the upper and lower surfaces of the cantilever substrate 52, such as Figure 1 , Figure 2 and Figure 4 shown.

[0034] like Figure 3As shown, preferably, there are two gears 44, which are located on both sides of the paddle 45, each gear 44 is meshed with a rack 43, each rack 43 is respectively arranged in two parallel slides 41, and a first spring 42 is arranged between each rack 43 and the slide 41. It is further preferred that the slide 41 is a vertical slide, the cover plate 1 covers the upper part of the vertical plate 6 and the slide 41, the vertical plate 6 and the slide 41 are respectively located below the opposite sides of the cover plate 1, and a second spring 3 is also arranged between the vertical plate 6 and the cover plate 1 (preferably, there are two second springs 3, and they match the two first springs 42), and it is further preferred that the multi-resonant piezoelectric energy harvester with up-conversion also includes a base 7 for carrying the slide 41, the bearing seat 48 and the vertical plate 6. It is preferred that the transmission column 2 is a column, the top end of the column is connected to the cover plate 1, the bottom end of the column passes through the top of the slide 41, extends into the slide 41, and can act on the top of the rack 43. It is further preferred that the power transmission module 4 further includes a rotating shaft 46, a bearing 47 and a bearing seat 48, the paddle 45 and the gear 44 are arranged on the rotating shaft 46, and the two ends of the rotating shaft 46 are rotatably connected to the bearing seat 48 through the bearing 47. It is further preferred that the first spring 42 is a tension spring, which is arranged between the top of the slide slot 41 and the top of the rack 43, and the second spring 3 is a compression spring, such as Figure 2 and Figure 3 shown.

[0035] like Figure 1 and Figure 2 As shown, the cover plate 1 is the force-bearing part of the external excitation (the second spring 3 (compression spring in the figure) connected to the cover plate 1 causes the compressed cover plate 1 to return to its original position), and the column 2 connected to the cover plate 1 moves down with the cover plate 1, and finally contacts the top of the rack 43, pushing the rack 43 down, so that the first spring 42 (tension spring in the figure) connected to the rack 43 is stretched, and after the external force disappears, the first spring 42 drives the rack 43 to resonate together. After the rack 43 resonates, it is transmitted to the gear 44 meshing with it, driving the coaxial gear 44 and the paddle 45 to rotate back and forth continuously, so that the paddle 45 continuously excites the piezoelectric energy harvesting module 5 to generate high-frequency self-resonance, and converts energy into electrical energy. The present invention converts the low-frequency vibration of the external excitation into the high-frequency vibration of the piezoelectric energy harvesting module 5, and converts the single excitation of the outside into the reciprocating resonance of the slider 41 and the multiple resonant motions of the piezoelectric energy harvesting module 5, thereby improving the energy collection efficiency and increasing the output of electrical energy.

[0036] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A multi-resonant piezoelectric energy harvester with up-conversion, characterized in that: include: A piezoelectric energy harvesting module (5) comprising a cantilever substrate (52) and a piezoelectric sheet (51) arranged along the length direction of the cantilever substrate (52); A power transmission module (4) comprising a rotatably arranged paddle (45) for paddle-moving a suspension end of a cantilevered substrate (52), a gear (44) coaxially arranged with the paddle (45) and acting synchronously, a rack (43) meshing with the gear (44), a slide groove (41) for guiding the movement of the rack (43), and a first spring (42) connected between the rack (43) and the slide groove (41); The cover plate (1) is used to receive external excitation, and the cover plate (1) can act on the rack (43) along the length direction of the slide groove (41) through the transmission column (2), and a second spring (3) for returning the cover plate (1) is provided between the cover plate (1) and the slide groove (41); It also includes a vertical plate (6), one end of the cantilevered base plate (52) is a suspended end, and the other end is a fixed end, and the fixed end is fixed to the vertical plate (6) via a clamping plate (53); The cantilever substrate (52) is arranged horizontally, and two piezoelectric sheets (51) are provided, respectively located on the upper and lower surfaces of the cantilever substrate (52); The transmission column (2) is a column, the top end of which is connected to the cover plate (1), and the bottom end of which passes through the top of the slide groove (41), extends into the slide groove (41), and can act on the top end of the rack (43).

2. A multi-resonant piezoelectric energy harvester with up-conversion according to claim 1, characterized in that: The power transmission module (4) further comprises a rotating shaft (46), a bearing (47) and a bearing seat (48); the paddle (45) and the gear (44) are inserted into the rotating shaft (46); and both ends of the rotating shaft (46) are rotatably connected to the bearing seat (48) via the bearing (47).

3. A multi-resonance piezoelectric energy harvester with up-conversion according to claim 1 or 2, characterized in that: The slide groove (41) is a vertical slide groove, the cover plate (1) covers the vertical plate (6) and the slide groove (41), and the second spring (3) is also arranged between the vertical plate (6) and the cover plate (1).

4. A multi-resonant piezoelectric energy harvester with up-conversion according to claim 1, characterized in that: The first spring (42) is a tension spring, which is arranged between the top of the slide groove (41) and the top of the rack (43), and the second spring (3) is a compression spring.

5. A multi-resonant piezoelectric energy harvester with up-conversion according to claim 1, characterized in that: There are two gears (44) located on both sides of the paddle (45), each gear (44) is meshed with a rack (43), each rack (43) is disposed in two parallel sliding grooves (41), and a first spring (42) is disposed between each rack (43) and the sliding groove (41).

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