Piezoelectric energy harvesting system based on self-parameter resonance and power generation method

Abstract

The invention discloses a piezoelectric energy harvesting system based on self-parameter resonance and a power generation method. The system comprises a main system, a secondary system and a fixed support, the main system is composed of a main beam and a piezoelectric element, the secondary system is composed of a secondary beam and a piezoelectric element, the main system is vertically connected with the fixed support through a first hinge, the near end of the secondary system is connected with the main system through a second hinge, and the far end of the secondary system is connected with the fixed support through a third hinge; the ratio of the inherent frequency of the primary system to the inherent frequency of the secondary system is 2: 1, so that self-parameter resonance coupling is achieved. According to the power generation method, the vibration energy of the main system is transmitted to the secondary system through nonlinear coupling, large-amplitude self-parameter resonance of the secondary system is induced, piezoelectric elements of the main system and the secondary system are made to generate remarkable deformation at the same time, and therefore mechanical energy is efficiently converted into electric energy through the direct piezoelectric effect. The energy conversion efficiency is remarkably improved through a self-parameter resonance mechanism, and an efficient solution is provided for large-scale environment energy collection.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of energy collection, in particular to a piezoelectric energy harvesting system and method based on self-parametric resonance. BACKGROUND

[0002] As an important means of environmental energy utilization, piezoelectric energy harvesting technology has shown great potential in the field of powering Internet of Things and low-power electronic devices. Traditional piezoelectric energy harvesting technology is mainly based on linear resonance principle, which realizes energy conversion by matching the natural frequency of piezoelectric structure with the external excitation frequency. However, this linear resonance mechanism has three fundamental limitations: first, the system can only work efficiently in a very narrow frequency band, making it difficult to adapt to the randomly changing excitation frequency in the actual environment; second, the energy conversion efficiency is severely dependent on the excitation strength, which performs poorly in low flow or weak vibration environment; third, a single resonance mode cannot fully stimulate the electromechanical conversion potential of piezoelectric materials, resulting in low output power density. These inherent defects make traditional piezoelectric energy harvesting systems face major challenges in practical applications.

[0003] In recent years, the development of nonlinear vibration theory has provided a new way to solve these problems. In particular, the phenomenon of self-parametric resonance has attracted widespread attention in the study of mechanical system dynamics due to its unique energy transfer characteristics. Self-parametric resonance refers to the phenomenon that when the natural frequencies of two coupled vibration systems satisfy a certain proportional relationship, the vibration energy of the main system can be excited to produce large resonance through nonlinear interaction. This mechanism can theoretically break through the limitations of linear resonance and achieve more efficient energy capture and conversion. However, to date, this important physical phenomenon has not been effectively applied to the field of piezoelectric energy harvesting, and relevant technical solutions are still in the blank. How to organically combine the principle of self-parametric resonance with piezoelectric conversion technology and develop a new type of efficient energy harvesting system has become a key problem and technical difficulty that needs to be solved in this field. SUMMARY

[0004] The purpose of the present application is to provide a piezoelectric energy harvesting system and method based on multi-frequency resonance to solve the above problems. The present application significantly improves the energy conversion efficiency through the self-parametric resonance mechanism, solves the performance limitation problem of traditional piezoelectric energy harvesting systems due to narrow linear resonance bandwidth and insufficient excitation strength, and provides an efficient solution for large-scale environmental energy collection.

[0005] The technical solution of the present application is specifically introduced as follows.

[0006] The application provides a piezoelectric energy capturing system based on self-parameter resonance, which comprises a main system, a secondary system and a fixed support; the main system is composed of a main beam and piezoelectric elements fixed on the main beam, and the secondary system is composed of a secondary beam and piezoelectric elements fixed on the secondary beam; the main system is connected with the fixed support perpendicularly through a first hinge, the proximal end of the secondary system is connected with the main system through a second hinge, and the distal end of the secondary system is connected with the fixed support through a third hinge; the natural frequency of the main system and the natural frequency of the secondary system satisfy the relationship of 2:1.

[0007] Preferably, the first hinge is a fixed hinge, the second hinge is a movable hinge, and the third hinge is a fixed hinge or a movable hinge.

[0008] Preferably, the secondary system is connected on the top of the main system, and the included angle between the main system and the secondary system is 90°.

[0009] Preferably, the main beam is made of PVC or spring steel material, and the secondary beam is made of spring steel or shape memory alloy material.

[0010] Preferably, the piezoelectric element is a piezoelectric ceramic material or a piezoelectric polymer film, the polarization direction of which is perpendicular to the vibration direction of the beam, and the thickness is 0.2-1mm.

[0011] Preferably, the frequency adjusting device comprises a slidable mass and an adjusting screw, and the position of the slidable mass is adjusted through the adjusting screw, so as to adjust the natural frequency of the main system or the secondary system.

[0012] Preferably, the energy collecting circuit comprises a full-wave rectification module and an energy storage capacitor, the full-wave rectification module is connected with the piezoelectric elements in the main system and the secondary system, converts the alternating current signals generated by the piezoelectric elements into direct current, and stores the direct current in the energy storage capacitor.

[0013] The application also provides a power generation method based on self-parameter resonance, which is realized based on the above system, and the specific steps are as follows: (a) making fluid flow through the main system at a certain flow rate; (b) when the vortex shedding frequency matches the natural frequency of the main system, exciting the main system to produce vortex-induced vibration; (c) through the frequency coupling relationship of 2:1, transmitting the vibration energy to the secondary system, and exciting the secondary system to produce self-parameter resonance; (d) the piezoelectric elements in the main system and the secondary system convert the mechanical vibration energy into electric energy output.

[0014] Preferably, the fluid flow rate is 0.5-10 m / s; the vibration amplitude of the secondary system is 2-20 times the vibration amplitude of the primary system, the difference in vibration amplitude is related to the connection mode of the distal end of the secondary system and the fixed support, and is also related to the structural material of the primary and secondary systems.

[0015] Preferably, when the fluid is air, the Reynolds number Re of the primary system is greater than 3000; when the fluid is a liquid, a waterproof coating is arranged on the surface of the primary system.

[0016] Preferably, the method further comprises a frequency self-adaptive adjustment step: the natural frequency of the system tracks the change of the fluid flow rate by adjusting the position of the mass block; at different flow rates, the vortex shedding frequency is different, and when the vortex shedding frequency is close to the natural frequency, resonance occurs.

[0017] Compared with the prior art, the method has the beneficial effects that: The self-parameter resonance principle is innovatively introduced into the piezoelectric energy harvesting field, and a novel piezoelectric energy harvesting system and a power generation method based on self-parameter resonance are provided. Self-parameter resonance is a special nonlinear resonance phenomenon, and when the natural frequencies of two vibration systems satisfy a specific proportional relationship (the proportional relationship can be derived by theory, and in the specific embodiments of the present application, a multiple relationship of 2:1 is adopted), the vibration energy of the primary system can excite the secondary system to produce large amplitude resonance through nonlinear coupling. Compared with traditional linear resonance, this mechanism has three outstanding advantages: it can realize efficient energy transfer and amplification; it has low dependence on initial excitation intensity; and it can maintain a stable resonance state in a wide frequency band.

[0018] The piezoelectric energy harvesting system based on self-parameter resonance of the present application realizes efficient capture and conversion of vibration energy through careful design of the frequency matching relationship of the primary and secondary systems and innovative mechanical coupling mode. The output power density of this new type of energy harvesting system is higher than that of traditional technology, and it can still maintain good performance in a weak vibration environment, opening up a new development direction for piezoelectric energy harvesting technology. This innovation not only solves the inherent limitations of traditional technology, but also provides a more efficient solution for environmental energy harvesting, and has important theoretical value and broad application prospects. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 The self-parameter resonance principle of the present application.

[0020] Figure 2 The structural schematic diagram of the present application.

[0021] In the figure: 1 is a fixed support, 2 is a primary system, 3 is a secondary system; 2-1 is a primary beam, 2-2 is a piezoelectric element; 3-1 is a secondary beam, 3-2 is a piezoelectric element, 4 is a sliding mass block, 5 is a full-wave rectification module, and 6 is an energy storage capacitor. DETAILED DESCRIPTION

[0022] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0023] like Figure 2 As shown, a piezoelectric energy harvesting system based on self-parametric resonance includes a fixed support 1, a main system 2, a secondary system 3, a sliding mass block 4, a full-wave rectifier module 5, and an energy storage capacitor 6. The main system includes a main beam 2-1 and a piezoelectric element 2-2, and the secondary system includes a secondary beam 3-1 and a piezoelectric element 3-2. The main system is perpendicularly connected to the fixed support via a first hinge, the proximal end of the secondary system is connected to the main system via a second hinge, and the distal end of the secondary system is connected to the fixed support via a third hinge.

[0024] During system installation, the fixed support is first securely installed in the target position to ensure stability. The main system is vertically connected to the support via a fixed hinge, and the near end of the secondary system is connected to the main system at a certain angle via a movable hinge, while the far end is connected to the fixed support via either a fixed hinge or a movable hinge. After installation, the sliding mass blocks on the main and secondary systems are adjusted to precisely set a specific relationship where the natural frequency ratio of the two is close to 2:1, which is a key condition for achieving self-parametric resonance.

[0025] When the system is placed in a fluid environment, the fluid flows through the main beam structure of the primary system, generating periodic vortex shedding behind it. When the vortex shedding frequency approaches the natural frequency of the primary system, it excites vortex-induced vibration in the primary system. Due to the pre-set 2:1 frequency ratio, the vibrational energy of the primary system is transferred to the secondary system through nonlinear coupling, inducing a large-amplitude self-parametric resonance in the secondary system. The amplitude of this resonance can reach 2-20 times that of the primary system's vibration, significantly improving energy capture efficiency.

[0026] During vibration, the piezoelectric elements in both the primary and secondary systems deform simultaneously, converting mechanical energy into electrical energy based on the piezoelectric effect. The generated alternating current signal is converted into direct current by a full-wave rectifier module and ultimately stored in an energy storage capacitor. Compared to a traditional single-resonance system, the synergistic effect of the primary and secondary systems improves energy conversion efficiency during system operation.

[0027] To adapt to different operating conditions, the system is designed with an adjustable mechanism. By adjusting the position of the sliding mass by adjusting the screw, the system's natural frequency is adjusted in real time to ensure that the vortex shedding frequency and the natural frequency are close, thus maintaining optimal operating conditions. This adaptive characteristic enables the system to maintain high-efficiency energy harvesting performance under varying fluid velocities.

[0028] Example 1 The application will be further described in conjunction with specific examples. However, it should be understood that these examples are only used to illustrate the application and do not limit the scope of the application. The test methods in the following examples, if not otherwise specified, are generally conducted under conventional conditions or under the conditions recommended by the manufacturers.

[0029] According to the piezoelectric energy harvesting system based on self-parameter resonance shown in the above embodiment, piezoelectric power generation is performed. Figure 2

[0030] The main beam is a PVC round pipe, the secondary beam is spring steel, and the piezoelectric element is a piezoelectric ceramic material. The main system is connected with the fixed support through a fixed hinge, the distal end of the secondary system is connected with the fixed support through a fixed hinge, and the proximal end of the main system and the proximal end of the secondary system are connected through a movable hinge. The natural frequency of the main system is 8.8 Hz, and the natural frequency of the secondary system is 4.4 Hz. The fluid is water, and the flow rate range is 0.86-0.92 m / s. When the main system is in self-vibration, the secondary system is in self-parameter resonance. The amplitude of the main system is 6.3 mm, and the amplitude of the secondary system is 22.2 mm; the amplitude of the self-parameter resonance of the secondary system is 13 times the amplitude of the ordinary resonance of the secondary system. Compared with the power generation efficiency when the secondary system is in ordinary resonance, the power generation efficiency of the piezoelectric energy harvesting system based on self-parameter resonance is increased by about 12 times. In other implementation conditions, the only difference is that the distal end of the secondary system is connected with the fixed support through a movable hinge. When the main system is in self-vibration, the amplitude of the self-parameter resonance of the secondary system is 3.6 times the amplitude of the ordinary resonance of the secondary system.

[0031] The above description of the embodiments is for the purpose of enabling and using the application by those of ordinary skill in the art. 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 labor. Therefore, the application is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the application without departing from the scope of the application should be within the scope of protection of the application.​

Claims

1. A piezoelectric energy harvesting system based on self-parametric resonance, characterized in that, It includes a main system, a subsystem, and a fixed support; the main system consists of a main beam and piezoelectric elements fixed on the main beam, and the subsystem consists of a secondary beam and piezoelectric elements fixed on the secondary beam; the main system is perpendicularly connected to the fixed support via a first hinge, the proximal end of the subsystem is connected to the main system via a second hinge, and the distal end of the subsystem is connected to the fixed support via a third hinge; the natural frequency of the main system and the natural frequency of the subsystem satisfy a 2:1 relationship.

2. The piezoelectric energy harvesting system based on self-parametric resonance according to claim 1, characterized in that, The first hinge is a fixed hinge, the second hinge is a movable hinge, and the third hinge is either a fixed hinge or a movable hinge.

3. The piezoelectric energy harvesting system based on self-parametric resonance according to claim 1, characterized in that, The secondary system is connected to the top of the main system, and the angle between the main system and the secondary system is 90°.

4. The piezoelectric energy harvesting system based on self-parametric resonance according to claim 1, characterized in that, The main beam is made of PVC or spring steel, the secondary beam is made of spring steel or shape memory alloy, and the piezoelectric element is a piezoelectric ceramic material or a piezoelectric polymer film with a polarization direction perpendicular to the vibration direction of the beam and a thickness of 0.2-1mm.

5. The piezoelectric energy harvesting system based on self-parametric resonance according to claim 1, characterized in that, It also includes a frequency adjustment device, which includes a sliding mass block and an adjustment screw. The position of the sliding mass block is adjusted by adjusting the adjustment screw, thereby adjusting the natural frequency of the main system or the secondary system.

6. The piezoelectric energy harvesting system based on self-parametric resonance according to claim 1, characterized in that, It also includes an energy harvesting circuit, which includes a full-wave rectifier module and an energy storage capacitor. The full-wave rectifier module is connected to the piezoelectric elements in the main system and the slave system, converting the AC signal generated by the piezoelectric elements into DC power and storing it in the energy storage capacitor.

7. A power generation method based on self-parametric resonance, implemented according to the system described in any one of claims 1-6, characterized in that, The specific steps are as follows: (a) To allow fluid to flow through the main system; (b) When the vortex shedding frequency matches the natural frequency of the main system, it excites the main system to generate vortex-induced vibration; (c) Vibrational energy is transferred to the subsystem through a 2:1 frequency coupling relationship, which excites the subsystem to generate self-parametric resonance; (d) The piezoelectric elements of the main system and the secondary system convert mechanical vibration energy into electrical energy output.

8. The power generation method according to claim 7, characterized in that, In step (a), the fluid velocity is 0.5-10 m / s; the vibration amplitude of the subsystem is 2-20 times that of the main system.

9. The power generation method according to claim 7, characterized in that, When the fluid is air, the Reynolds number Re of the main system is greater than 3000; when it is a liquid, the surface of the main system is provided with a waterproof coating.

10. The power generation method according to claim 7, characterized in that, It also includes a frequency adaptive adjustment step: by adjusting the position of the mass block, the system's natural frequency tracks the changes in fluid velocity.

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