Piezoelectric power generation system for capturing wave energy

Abstract

The present invention discloses a piezoelectric power generation system for capturing wave energy, comprising a piezoelectric power generation device, a float, a column and a base, wherein the piezoelectric power generation device comprises an outer ring, an inner ring and a piezoelectric power generation group, wherein the float is connected to the inner ring through the rocker, and the outer ring is connected to the base through the column. The float of the system transmits low-frequency vibration (originating from waves) to the piezoelectric power generation device through the rocker, and the piezoelectric power generation device uses the cooperation of multiple groups of piezoelectric components on the inner ring and multiple groups of magnets on the outer ring to realize high-frequency vibration power generation of the piezoelectric components, so as to improve the power generation efficiency.

Description

Technical Field

[0001] The invention belongs to the field of power generation devices, and in particular relates to a piezoelectric power generation system for capturing wave energy. Background Art

[0002] In order to realize the self-powering of wireless sensors used for marine environmental monitoring, many scholars at home and abroad have proposed the use of electromagnetic induction law, piezoelectric effect and triboelectric effect to convert wave energy into electrical energy to power wireless sensors, and designed a variety of small power generation devices. Most of these devices use resonant mechanical structures. Taking electromagnetic power generation devices as an example, the magnets vibrate back and forth under the drive of waves, cutting the magnetic flux lines to generate induced electromotive force in the coil. This resonant power generation device reaches the maximum output power when the external excitation frequency is equal to its own natural frequency.

[0003] Although the existing resonant power generation device can generate a large output power when the external excitation frequency is equal to its own natural frequency, that is, when it reaches the resonance state. However, its working frequency range is very narrow. This resonant power generation device can only work normally in a very narrow frequency range near the natural frequency. For most power generation devices based on environmental vibration, their own natural frequency is much greater than the frequency of environmental vibration. According to the theoretical formula, the output power of the power generation device is proportional to the cube of its working frequency. This means that when the excitation frequency of the external environment decreases, the output power of the power generation device will drop sharply. In order to make the output power as large as possible, the natural frequency of the power generation device must be close to the frequency of the environmental vibration. Environmental vibration is a low-frequency vibration, and its frequency range is generally 1-20Hz. The frequency of the wave is less than 5Hz. If the natural frequency of the power generation device is close to it, the overall size of the power generation device must be increased, because generally speaking, the natural frequency of the power generation device is inversely proportional to its overall size. However, the increase in the volume of the power generation device will greatly reduce its output power density (the ratio of output power to its working volume), and will also bring about a series of problems such as increased manufacturing costs and increased installation difficulty. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a piezoelectric power generation system for capturing wave energy. The float of the system transmits low-frequency vibrations (originating from waves) to a piezoelectric power generation device through a rocker. The piezoelectric power generation device uses multiple groups of piezoelectric components on the inner ring and multiple groups of magnets on the outer ring to achieve high-frequency vibration power generation of the piezoelectric components to improve the power generation efficiency.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A piezoelectric power generation system for capturing wave energy comprises a piezoelectric power generation device, a float, a column and a base, wherein the piezoelectric power generation device comprises an outer ring, an inner ring and a piezoelectric power generation group; wherein:

[0007] The outer ring is a cylindrical structure with one end open, and a rotation groove and an inner column arranged at the center of the bottom inner wall are provided on the bottom inner wall of the outer ring; at least two groups of magnets are evenly arranged along the circumferential direction on the inner surface of the side wall of the outer ring, and at least two groups of magnets are evenly arranged along the circumferential direction on the surface of the inner column; a transparent rocker movable groove is provided on the side wall of the outer ring along the circumferential direction;

[0008] The inner ring is provided with a rocker, and the rocker extends from the inner ring through the rocker movable groove to the outer ring; the edge of the inner ring is provided with a rectangular convex edge, and the rectangular convex edge cooperates with the rotating groove of the outer ring so that the outer ring and the inner ring can rotate relative to each other;

[0009] The inner ring is provided with at least two piezoelectric power generation groups along the circumferential direction, and the piezoelectric power generation groups include piezoelectric components, and the piezoelectric components are fixedly connected to the inner ring, and one end of the piezoelectric components faces the inner surface of the side wall of the outer ring, and the other end faces the inner column;

[0010] The float is connected to the inner ring through the rocker, and the outer ring is connected to the base through the column.

[0011] In a specific embodiment, the piezoelectric component includes a cantilever beam, a piezoelectric sheet and two magnets. The piezoelectric sheet is attached to the cantilever beam, and the two magnets are respectively fixed at two ends of the cantilever beam.

[0012] In a specific embodiment, a rectangular groove is provided on the inner ring, and the middle position of the cantilever beam of the piezoelectric component is fixedly connected to the rectangular groove of the inner ring.

[0013] In a specific embodiment, the number of piezoelectric sheets of the piezoelectric assembly is 4, and the 4 piezoelectric sheets are symmetrically attached to the upper and lower surfaces of the cantilever beam along the middle position of the cantilever beam.

[0014] In a specific embodiment, the polarities of the end faces of the magnet of the piezoelectric component and the magnet of the outer ring facing each other are the same.

[0015] In a specific embodiment, each of the piezoelectric power generation groups includes three piezoelectric components, and the three piezoelectric components are arranged along the radial direction of the inner ring.

[0016] In a specific embodiment, each group of magnets on the outer ring located at the rocker movable slot includes two magnets, and each other group of magnets includes three magnets.

[0017] In a specific embodiment, the circumferential angle of the rocker movable slot is 90 degrees.

[0018] In a specific embodiment, there are three groups of magnets on the inner surface of the side wall of the outer ring, and there are three groups of magnets on the surface of the inner column.

[0019] The present invention has the following beneficial effects:

[0020] 1. Use floats and rockers to convert the up and down motion of the waves into the rotational motion of the inner ring (rotor).

[0021] 2. Cantilever beams and piezoelectric sheets are arranged on the inner and outer sides of the inner ring (rotor) to improve the output power density.

[0022] 3. The cooperation of multiple groups of piezoelectric components on the inner ring and multiple groups of magnets on the outer ring constitutes a frequency-increasing mechanism, which uses the interaction force between the magnets to drive the cantilever beam to oscillate freely, and then uses the higher-frequency vibration of the cantilever beam to generate electricity.

[0023] 4. Piezoelectric sheets are arranged on the upper and lower surfaces of the cantilever beam, and the deformation of the cantilever beam is fully utilized to generate electricity according to the piezoelectric effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A schematic diagram of a piezoelectric power generation system according to an embodiment of the present invention;

[0025] Figure 2 This is a schematic diagram of a piezoelectric power generation device according to an embodiment of the present invention;

[0026] Figure 3 An exploded diagram of a piezoelectric power generation device;

[0027] Figure 4 It is the structural diagram and explosion diagram of the piezoelectric component;

[0028] Figure 5 This is a working principle diagram of a piezoelectric power generation device;

[0029] Figure 6 The working principle diagram of the piezoelectric component. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Reference Figures 1 to 6The present invention discloses a piezoelectric power generation system for capturing wave energy, the system comprising a float 1, a piezoelectric power generation device 30, a column and a base 40, the float 1 is connected to the piezoelectric power generation device 30 through a rocker 2, and the piezoelectric power generation device 30 is fixed to the base 40 through a column.

[0032] The piezoelectric generator 30 includes an outer ring 3, an inner ring 4 and a piezoelectric generator group 6. The outer ring 3 is provided with a rectangular rocker movable groove 31 with a central angle of 90 degrees along the circumferential direction. The rocker 2 can swing up and down along the rocker movable groove 31, and the rocker 2 passes through the outer ring 3 and extends to the inner ring 4 and is fixedly connected to the inner ring 4. When the rocker 2 swings up and down, the inner ring 4 and the outer ring 3 will rotate relative to each other.

[0033] A rotation groove 32 is provided on the inner wall of the bottom of the outer ring 3, and the rotation groove 32 cooperates with a plurality of rectangular convex edges 41 provided on the edge of the inner ring 4 to form a rotation pair, so that the outer ring 3 and the inner ring 4 can rotate relative to each other. An inner column 5 is provided at the center of the inner wall of the bottom of the outer ring 3, and the inner column 5 is fixedly connected to the inner wall of the bottom of the outer ring 3.

[0034] The outer ring 3 is cylindrical, and magnet groups are embedded on the inner surface of the side wall of the outer ring 3 and the surface of the inner column 5. In a specific embodiment, 12 groups of magnet groups are evenly distributed on the inner surface of the side wall of the outer ring 3 at a central angle of 30 degrees along the circumferential direction, wherein, except for each group of magnet groups at the rocker movable groove 31 having only two magnets, the remaining groups of magnet groups are each provided with three magnets. Six groups of magnet groups are evenly distributed on the surface of the inner column 5 at a central angle of 60 degrees along the circumferential direction, and each group of magnet groups has three magnets.

[0035] The inner ring 4 is in the shape of a thin-walled cylinder, and 6 groups of rectangular grooves 7 are evenly arranged along the circumference of the inner ring 4 (at intervals of 60 degrees at the central angle), and each group has 3 rectangular grooves 7 arranged along the radial direction of the inner ring 4. Correspondingly, the 3 piezoelectric components 8 arranged in the radial direction constitute a piezoelectric power generation group 6. A piezoelectric component 8 is fixedly connected with the inner ring 4 through the rectangular groove 7, that is, the middle part of the power generation component 8 forms an interference fit with the rectangular groove 7. The piezoelectric components 8 correspond to the rectangular grooves 7 one by one, and a total of 6 groups, i.e. 18 piezoelectric components 8, are installed on the inner ring 4.

[0036] The piezoelectric assembly 8 includes a cantilever beam 81 (a brass sheet may be used), four piezoelectric sheets 82 and two magnets 83. The cantilever beam 81 is a brass sheet with a thickness of 0.4 mm. The middle of the cantilever beam 81 is fixedly connected to the rectangular groove 7 of the inner ring 4. A magnet 83 is installed on each of the two free ends of the cantilever beam 81. Four piezoelectric sheets 82 are symmetrically attached to the upper and lower surfaces of the cantilever beam 81 along the middle position.

[0037] The working principle of the piezoelectric power generation system described in the present invention is as follows. When the float 1 vibrates up and down with the waves, it will swing the rocker 2 up and down, causing the inner ring 4 and the outer ring 3 to rotate relative to each other. There is a very small gap between the piezoelectric power generation group 6 installed on the inner ring 4 and the inner surface of the side wall of the outer ring 3, and between the piezoelectric power generation group 6 and the surface of the inner column 5. When the inner ring 4 and the outer ring 3 rotate relative to each other, the magnets 83 at both ends of the cantilever beam 81 interact with the magnets on the inner surface of the side wall of the outer ring 3 and the magnets on the inner column 5 respectively. Under the action of the magnetic force, the cantilever beam 81 will deform, so that the piezoelectric sheet 82 attached to the surface of the cantilever beam 81 will also deform. According to the positive piezoelectric effect, the piezoelectric sheet under pressure (or tension) will output electrical energy.

[0038] The specific vibration power generation process of the piezoelectric component 8 is as follows. When the inner ring 4 and the outer ring 3 rotate relative to each other, the magnet 33 on the outer ring 3 vibrates up and down relative to the magnet 83 of the piezoelectric component 8. When the magnet 33 on the outer ring 3 approaches the magnet 83 on the cantilever beam 81, an interaction force is generated between the magnets, and this force drives the cantilever beam 81 to bend. When the magnet 83 continues to move relative to the cantilever beam and gradually moves away from the cantilever beam, the force weakens and the cantilever beam 81 is released. After being released, the cantilever beam 81 will vibrate freely at its natural frequency. The frequency of the swing of the rocker 2 is equal to the frequency of the wave motion, which is usually very low (<5Hz), but during the swing of the rocker 2, the cantilever beam 81 will vibrate freely at its natural frequency every time it is moved by the magnet 33 on the outer ring 3. This natural frequency is much higher than the frequency of the wave and can reach hundreds of hertz. This achieves an increase in frequency, and ultimately achieves an increase in the output power and energy conversion efficiency of the piezoelectric power generation device.

[0039] The piezoelectric power generation system described in the present invention can efficiently realize the conversion of wave energy into electrical energy, can replace the batteries of wireless sensors used for marine environment monitoring, avoids the trouble of battery replacement and recharging, and provides great help for the establishment of the marine Internet of Things.

[0040] The piezoelectric power generation system for capturing wave energy described in the present invention can be understood as two vibration systems connected in series, one is a low-frequency vibration system (float end), and the other is a high-frequency vibration system (piezoelectric power generation device end). The low-frequency vibration system can transmit low-frequency environmental (wave) vibrations to the high-frequency vibration system, and the high-frequency vibration system uses an electromechanical conversion mechanism to convert the vibration energy into electrical energy. The introduction of this up-conversion structure brings two basic advantages: first, the vibration frequency used for power generation has been greatly improved, which directly leads to an increase in output power density; second, the natural frequency of the power generation device can be made close to the environmental vibration frequency without increasing the overall size of the power generation device.

[0041] In addition, the electromechanical conversion mechanism adopted by the present invention is the piezoelectric effect (when the piezoelectric sheet is deformed, polarization will occur inside, thereby generating an electromotive force). Compared with the traditional electromagnetic power generation device, this piezoelectric power generation device can more fully utilize the low frequency and large amplitude characteristics of wave energy and more efficiently complete the conversion of electrical energy. Because according to Faraday's law of electromagnetic induction, the output power of the electromagnetic power generation device is proportional to the rate of change of the magnetic flux lines inside the coil, that is, it is proportional to the movement speed of the magnet, so the frequency of the wave has a great influence on it and the amplitude of the wave has a small influence on it, which cannot bring into play the advantage of the large amplitude of the wave. However, the present invention is a piezoelectric power generation device, and the large amplitude of the wave will directly lead to an increase in the number of vibrations of the piezoelectric sheet, so the frequency and amplitude of the wave both affect the power output of the power generation device.

[0042] The present invention solves the problem of difficulty in generating power from low-frequency and large-amplitude wave energy by combining a frequency-upgrading mechanism with an electromechanical conversion mechanism based on the piezoelectric effect, thereby improving the conversion efficiency of electric energy and the output power density. The present invention has great application potential in realizing self-power supply for marine electronic devices such as wireless sensors used for marine environment monitoring.

[0043] It should be understood that the exemplary embodiments described herein are illustrative rather than restrictive. Although one or more embodiments of the present invention have been described in conjunction with the accompanying drawings, it should be understood by those skilled in the art that various changes in form and detail may be made without departing from the spirit and scope of the present invention as defined by the appended claims.

Claims

1. A piezoelectric power generation system for capturing wave energy, characterized in that: The piezoelectric power generation system comprises a piezoelectric power generation device, a float, a column and a base, wherein the piezoelectric power generation device comprises an outer ring, an inner ring and a piezoelectric power generation group; wherein the outer ring is a cylindrical structure with one end open, a rotating groove is provided on the inner wall of the bottom of the outer ring and an inner column is provided at the center of the inner wall of the bottom; at least two groups of magnets are evenly provided on the inner surface of the side wall of the outer ring along the circumferential direction, and at least two groups of magnets are evenly provided on the surface of the inner column along the circumferential direction; a transparent rocker movable groove is provided on the side wall of the outer ring along the circumferential direction; The inner ring is provided with a rocker, and the rocker extends from the inner ring through the rocker movable groove to the outer ring; the edge of the inner ring is provided with a rectangular convex edge, and the rectangular convex edge cooperates with the rotating groove of the outer ring so that the outer ring and the inner ring can rotate relative to each other; The inner ring is provided with at least two piezoelectric power generation groups along the circumferential direction, and the piezoelectric power generation groups include piezoelectric components, and the piezoelectric components are fixedly connected to the inner ring, and one end of the piezoelectric components faces the inner surface of the side wall of the outer ring, and the other end faces the inner column; The float is connected to the inner ring through the rocker, and the outer ring is connected to the base through the column; The piezoelectric component includes a cantilever beam, a piezoelectric sheet and two magnets, the piezoelectric sheet is attached to the cantilever beam, and the two magnets are respectively fixed at both ends of the cantilever beam; The inner ring is provided with a rectangular groove, and the middle position of the cantilever beam of the piezoelectric component is fixedly connected to the rectangular groove of the inner ring; The number of piezoelectric sheets of the piezoelectric assembly is 4, and the 4 piezoelectric sheets are symmetrically attached to the upper and lower surfaces of the cantilever beam along the middle position of the cantilever beam; Each of the piezoelectric power generation groups includes three piezoelectric components, and the three piezoelectric components are arranged along the radial direction of the inner ring.

2. The piezoelectric power generation system for capturing wave energy according to claim 1, characterized in that: The polarities of the end faces of the magnet of the piezoelectric component and the magnet of the outer ring facing each other are the same.

3. The piezoelectric power generation system for capturing wave energy according to claim 1, characterized in that: Each group of magnets on the outer ring located at the rocker movable slot includes two magnets, and each other group of magnets includes three magnets.

4. The piezoelectric power generation system for capturing wave energy according to claim 1, characterized in that: The circumferential angle of the rocker movable groove is 90 degrees.

5. The piezoelectric power generation system for capturing wave energy according to claim 1, characterized in that: There are three groups of magnets on the inner surface of the side wall of the outer ring, and there are three groups of magnets on the surface of the inner column.

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