Magnetic coupling type bimodal piezoelectric energy collecting device

Abstract

The invention discloses a magnetic coupling type bimodal piezoelectric energy collecting device. The device is composed of a base, a piezoelectric cantilever beam, a mass block and a permanent magnet. Each piezoelectric cantilever beam comprises two piezoelectric patches and is connected with an external load in series; the mass block is fixed at the tail ends of the two piezoelectric cantilever beams to form an L-shaped structure; one permanent magnet is fixed to the free end of the horizontal piezoelectric cantilever beam, the other two permanent magnets are fixed to the base, and the magnets are arranged in a magnetic repulsion mode. According to the designed structure, the inherent frequency of each mode can be effectively reduced, the bimodal characteristic enables the device to present two voltage peak values in a low-frequency environment, and the output voltage under a broadband is improved. Besides, interaction between the magnets is utilized, so that the device shows nonlinear dynamic characteristics, the operation frequency band of the device is further widened, the energy collection efficiency is improved, and the application range of the piezoelectric energy collection device is expanded.

Description

Technical Field

[0001] The present invention belongs to the technical field of piezoelectric energy collection, and in particular relates to a magnetically coupled nonlinear dual-mode piezoelectric energy collection device. Background Art

[0002] With the widespread application of IoT devices, wearable devices, and wireless sensor networks, low-power, long-life self-powered technology has become a research hotspot. Piezoelectric energy harvesting technology has received widespread attention and application due to its simple structure, easy integration, and ability to continuously harvest energy from environmental vibrations. However, traditional piezoelectric energy harvesters still have certain limitations, including high natural frequency and narrow operating bandwidth. When the natural frequency of the system matches the vibration frequency of the environment, the energy harvesting efficiency is higher. However, the vibrations in the environment are often low-frequency and variable, with a certain degree of randomness. Therefore, traditional piezoelectric energy harvesters are difficult to adapt to broadband, low-frequency environmental vibration sources. This limitation limits the application scenarios of traditional devices.

[0003] In order to solve these problems, researchers have tried to broaden the operating frequency range and reduce the natural frequency of the collector by changing its structural parameters, such as by changing the size of the beam, adding a mass block, etc. However, the effects of these methods are limited, and while broadening the frequency bandwidth is often accompanied by a decrease in energy collection efficiency. Therefore, the present invention designs a magnetically coupled dual-mode piezoelectric energy harvesting device, which can effectively reduce the natural frequency of each mode, so that the device exhibits two voltage peaks in a low-frequency environment, thereby increasing the output voltage of the device and realizing dual-mode piezoelectric energy collection. In addition, the present invention utilizes the interaction between magnets to make the device exhibit nonlinear dynamic characteristics, thereby further broadening the operating frequency band of the device, improving the energy collection efficiency, and making it more practical. Summary of the invention

[0004] The present invention designs a magnetically coupled dual-mode piezoelectric energy harvesting device, comprising: a base, a piezoelectric cantilever beam, a mass block and a permanent magnet;

[0005] The base includes a rectangular horizontal substrate and a rectangular vertical substrate; the piezoelectric cantilever beam includes a vertical piezoelectric cantilever beam and a horizontal piezoelectric cantilever beam; and the permanent magnet includes an end magnet, a first external magnet and a second external magnet.

[0006] The vertical piezoelectric cantilever beam comprises a first piezoelectric sheet, a vertical elastic matrix and a second piezoelectric sheet; one end of the vertical piezoelectric cantilever beam is fixed to the rectangular horizontal substrate, and the other end is connected to the mass block.

[0007] The horizontal piezoelectric cantilever beam comprises a third piezoelectric sheet, a horizontal elastic matrix and a fourth piezoelectric sheet; one end of the horizontal piezoelectric cantilever beam away from the rectangular vertical substrate is connected to the mass block.

[0008] The first piezoelectric sheet and the second piezoelectric sheet are connected in series; the third piezoelectric sheet and the fourth piezoelectric sheet are connected in series.

[0009] Preferably, a magnetic attraction arrangement is adopted between the end magnet and the first external magnet and the second external magnet.

[0010] Preferably, the end magnet, the first external magnet and the second external magnet are all made of neodymium iron boron permanent magnets.

[0011] Preferably, the rectangular horizontal substrate, the rectangular vertical substrate and the mass block are all made of aluminum alloy material.

[0012] Preferably, the first piezoelectric sheet, the second piezoelectric sheet, the third piezoelectric sheet and the fourth piezoelectric sheet are all made of piezoelectric ceramics.

[0013] Preferably, the vertical elastic matrix and the horizontal elastic matrix are both made of brass material.

[0014] Beneficial effects of the present invention:

[0015] 1. The device designed in the present invention can effectively reduce the natural frequency of each mode, so that the device presents two voltage peaks in a low-frequency environment, thereby increasing the output voltage of the device and realizing dual-mode piezoelectric energy collection.

[0016] 2. By introducing the interaction of magnets, the device exhibits tristable characteristics and has a wider and shallower potential energy well. The shallower potential energy well enables the device to produce large-amplitude inter-well motion at a lower excitation intensity; the wider potential energy well expands the operating frequency band of the device and improves the piezoelectric energy collection efficiency.

[0017] 3. The device has a compact structure and strong practicality. It can be widely used in external vibration environments to provide energy for low-power devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly understand the embodiments of the present invention, the following drawings used in the embodiments are described:

[0019] Figure 1 A schematic diagram of the structure of the magnetically coupled dual-mode piezoelectric energy harvesting device provided by the present invention.

[0020] Figure 2 This is a simulation diagram of the output voltage of the magnetically coupled dual-mode piezoelectric energy harvesting device provided by the present invention.

[0021] Figure 3 This is a potential energy simulation diagram of the magnetically coupled dual-mode piezoelectric energy harvesting device provided by the present invention. DETAILED DESCRIPTION

[0022] The specific implementation modes of the present invention will be described in detail below with reference to the accompanying drawings.

[0023] like Figure 1 As shown, the present invention designs a magnetically coupled dual-mode piezoelectric energy harvesting device, including: a base, a piezoelectric cantilever beam, a mass block, and a permanent magnet.

[0024] The base includes a rectangular horizontal substrate 1 and a rectangular vertical substrate 2; the piezoelectric cantilever beam includes a vertical piezoelectric cantilever beam 3 and a horizontal piezoelectric cantilever beam 4; the permanent magnet includes an end magnet 6, a first external magnet 7 and a second external magnet 8. The vertical piezoelectric cantilever beam 3 includes a first piezoelectric sheet 301, a vertical elastic matrix 302 and a second piezoelectric sheet 303; one end of the vertical piezoelectric cantilever beam 3 is fixed to the rectangular horizontal substrate 1, and the other end is connected to the mass block 5. The horizontal piezoelectric cantilever beam 4 includes a third piezoelectric sheet 401, a horizontal elastic matrix 402 and a fourth piezoelectric sheet 403; one end of the horizontal piezoelectric cantilever beam 4 away from the rectangular vertical substrate 2 is connected to the mass block 5. The first piezoelectric sheet 301 and the second piezoelectric sheet 303 are connected in series, and the third piezoelectric sheet 401 and the fourth piezoelectric sheet 403 are connected in series. The end magnet 6 and the first external magnet 7 and the second external magnet 8 are arranged in a magnetic attraction manner. The first piezoelectric sheet 301, the second piezoelectric sheet 303, the third piezoelectric sheet 401 and the fourth piezoelectric sheet 403 are all made of piezoelectric ceramics. The vertical elastic matrix 302 and the horizontal elastic matrix 402 are all made of brass. The end magnet 6, the first external magnet 7 and the second external magnet 8 are all made of neodymium iron boron permanent magnets. The rectangular horizontal substrate 1, the rectangular vertical substrate 2 and the mass block 5 are all made of aluminum alloy.

[0025] like Figure 2 As shown in the figure, when the device is stimulated by the external environment, the piezoelectric sheet can convert vibration energy into electrical energy. Since the device can effectively reduce the natural frequency of each mode, the device presents two voltage peaks in a low-frequency environment, which increases the output voltage of the device and realizes dual-mode piezoelectric energy collection. Figure 3 As shown, when d = 2d g =0.5L, where L is the length of the vertical piezoelectric cantilever beam, the device exhibits tristable characteristics and has a wider and shallower potential energy well. The shallower potential energy well enables the device to produce large-amplitude inter-well motion at a lower excitation intensity; the wider potential energy well expands the operating frequency band of the device and improves the piezoelectric energy collection efficiency.

[0026] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A magnetically coupled dual-mode piezoelectric energy harvesting device, characterized in that: include: Base, piezoelectric cantilever beam, mass and permanent magnet; The base comprises a rectangular horizontal substrate (1) and a rectangular vertical substrate (2); the piezoelectric cantilever beam comprises a vertical piezoelectric cantilever beam (3) and a horizontal piezoelectric cantilever beam (4); and the permanent magnet comprises an end magnet (6), a first external magnet (7) and a second external magnet (8).

2. The magnetically coupled dual-mode piezoelectric energy harvesting device according to claim 1, characterized in that: The vertical piezoelectric cantilever beam (3) comprises a first piezoelectric sheet (301), a vertical elastic matrix (302) and a second piezoelectric sheet (303); one end of the vertical piezoelectric cantilever beam (3) is fixed to the rectangular horizontal substrate (1), and the other end is connected to the mass block (5).

3. The magnetically coupled dual-mode piezoelectric energy harvesting device according to claim 1, characterized in that: The horizontal piezoelectric cantilever beam (4) comprises a third piezoelectric sheet (401), a horizontal elastic matrix (402) and a fourth piezoelectric sheet (403); one end of the horizontal piezoelectric cantilever beam (4) away from the rectangular vertical substrate (2) is connected to the mass block (5).

4. The magnetically coupled dual-mode piezoelectric energy harvesting device according to claim 2, characterized in that: The first piezoelectric sheet (301) and the second piezoelectric sheet (303) are connected in series; the third piezoelectric sheet (401) and the fourth piezoelectric sheet (403) are connected in series.

5. The magnetically coupled dual-mode piezoelectric energy harvesting device according to claim 1, characterized in that: There is a magnetic attraction between the end magnet (6) and the first external magnet (7) and the second external magnet (8).

6. The magnetically coupled dual-mode piezoelectric energy harvesting device according to claim 5, characterized in that: The end magnet (6), the first external magnet (7) and the second external magnet (8) are all made of neodymium iron boron permanent magnets.

7. The magnetically coupled dual-mode piezoelectric energy harvesting device according to claim 1, characterized in that: The rectangular horizontal substrate (1), the rectangular vertical substrate (2) and the mass block (5) are all made of aluminum alloy material.

8. The magnetically coupled dual-mode piezoelectric energy harvesting device according to claim 2, characterized in that: The first piezoelectric sheet (301), the second piezoelectric sheet (303), the third piezoelectric sheet (401) and the fourth piezoelectric sheet (403) are all made of piezoelectric ceramics.

9. The magnetically coupled dual-mode piezoelectric energy harvesting device according to claim 2, characterized in that: The vertical elastic base (302) and the horizontal elastic base (402) are both made of brass material.

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