CN105680717A - Blade-type composite pneumatic energy collector - Google Patents

Abstract

A blade-type composite wind energy harvester, including a piezoelectric energy harvesting module and a frictional energy harvesting module; the piezoelectric energy harvesting module includes a blade and a flexible piezoelectric cantilever arm; the free end of the blade and the flexible piezoelectric cantilever arm Connected in parallel, the blades can drive the flexible piezoelectric cantilever to vibrate periodically in the frame; the friction energy harvesting module includes a moving friction layer pasted on the surface of the flexible piezoelectric cantilever and a fixed friction layer pasted on the inner surface of the frame; the moving friction The layer and the fixed friction layer can periodically contact and separate in the frame. The collector adopts two energy collection methods of friction and piezoelectricity, which improves the energy output density. The blade design at the end of the cantilever beam can better respond to the disturbance of the wind fluid, which improves the amplitude and piezoelectric voltage output of the piezoelectric cantilever beam. At the same time, the design of the double-arc current blocking structure of the frame can increase the contact area between the friction layers and improve the friction voltage output.

Description

A blade-type composite wind energy harvester

technical field

The invention relates to the field of energy collection and conversion equipment, in particular to a blade-type composite wind energy collector.

Background technique

At present, wireless sensor networks are widely used in environmental monitoring, smart home, transportation, medical health and other fields, but the power supply problem of wireless sensor nodes has become a key factor restricting its development. The traditional battery power supply method has problems such as large volume, short life, and difficult replacement, especially in remote uninhabited areas. Harvesting energy from the environment to power wireless sensor nodes is an effective way to replace batteries.

As a non-polluting and renewable clean energy, wind energy has great potential for development, especially for coastal islands, remote mountainous areas with inconvenient transportation, sparsely populated grasslands and pastures, and rural areas that are far away from the power grid and are difficult to reach in the near future. , Frontier, as a reliable way to solve production and living energy, has very important significance. Even in developed countries, wind energy is increasingly valued as an efficient and clean new energy source. Harvesting wind energy to supply power to wireless sensor networks, wireless sensor nodes, and embedded low-power electronic devices working outdoors has broad prospects and is being studied more and more widely. Wind energy harvesters with various structures emerge in endlessly. The most common structures are windmill structure, resonant cavity structure and cantilever beam structure. At present, wind energy harvesters that can achieve high output are often bulky and complex in structure. Although the existing wind energy harvester with cantilever beam structure is simple in structure and small in size, its high operating frequency and small amplitude lead to low voltage output and it is difficult to obtain ideal power output.

In view of the above problems, it is necessary to propose a wind energy harvester that can realize efficient conversion of wind energy into electric energy at low wind speed, and has the characteristics of high amplitude and high output, so as to solve the above problems.

Contents of the invention

In view of this, the present invention provides a high-amplitude, high-output blade-type composite wind energy collector.

In order to achieve the above object, the technical scheme adopted in the present invention is:

A blade-type composite wind energy harvester, characterized in that it includes a piezoelectric energy harvesting module and a frictional energy harvesting module;

The piezoelectric energy harvesting module includes a blade and a flexible piezoelectric cantilever; the blade is connected to the free end of the flexible piezoelectric cantilever, and the blade can drive the flexible piezoelectric cantilever to periodically vibrate in the frame;

The frictional energy harvesting module includes a moving friction layer pasted on the surface of the flexible piezoelectric cantilever arm and a fixed friction layer pasted on the inner surface of the frame; the moving friction layer and the fixed friction layer can be in periodic relative contact with each other in the frame separation;

The frame is fixed at the end of the frame and the flexible piezoelectric cantilever arm through gaskets; an electrode layer is pasted between the frame and the fixed friction layer.

The blade is connected in parallel with the free end of the flexible piezoelectric cantilever arm through a hinge.

The moving friction layer is a metal friction layer, which is symmetrically pasted on the upper and lower surfaces of the flexible piezoelectric cantilever arm.

The fixed friction layer is a polydimethylsiloxane friction layer with multiple pyramid microstructure friction units.

The shape of the blade can be square, rectangular, circular, or rhombus.

The frame is a bluff body structure.

The shape of the frame is double arc or shuttle.

Compared with the prior art, the present invention designs a blade type composite wind energy collector aiming at the problems of low amplitude and low output of the cantilever beam structure wind energy collector. The collector can realize high-efficiency conversion of wind energy into electric energy at low wind speed. The simultaneous operation of both friction and piezoelectric energy harvesting methods increases the energy output density of the harvester. The blade design at the end of the cantilever beam can better respond to the disturbance of the wind fluid, which improves the amplitude and piezoelectric voltage output of the piezoelectric cantilever beam. At the same time, the structural design of the double arc (shuttle) blocking current can increase the contact area between the friction materials and improve the friction voltage output.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is the structural representation of blade type composite wind energy harvester provided by the present invention;

Fig. 2 is the working principle diagram of the blade type composite wind energy harvester provided by the present invention;

Fig. 3 is the charge transfer diagram of the frictional energy harvesting module in the blade type composite wind energy harvester provided by the present invention;

Fig. 4 is a test chart of the output characteristics of the blade-type composite wind energy harvester provided by the present invention.

Reference signs and component parts involved in the accompanying drawings:

1. Frame; 2. Gasket; 3. Flexible piezoelectric cantilever arm; 4. Electrode layer; 5. Fixed friction layer; 6. Moving friction layer; 7. Blade; 8. Vortex.

detailed description

In the prior art, wind energy harvesters that can achieve high output are usually large in size and complex in structure. Although the existing wind energy harvester with cantilever beam structure is simple in structure and small in size, its high operating frequency and small amplitude lead to low voltage output and it is difficult to obtain ideal power output.

Aiming at the deficiencies of the prior art, the present invention provides a wind energy collector capable of efficiently converting wind energy into electric energy at low wind speeds and featuring high amplitude and high output. A blade-type composite wind energy harvester has two voltage output modes that cooperate with each other, a piezoelectric type and a friction type, and includes a piezoelectric energy harvesting module and a frictional energy harvesting module.

The piezoelectric energy harvesting module includes blades and flexible piezoelectric cantilever arms, the blades are connected to the free ends of the flexible piezoelectric cantilever arms, and the blades can drive the flexible piezoelectric cantilever arms to vibrate periodically in the frame.

The frictional energy harvesting module includes a moving friction layer pasted on the surface of the flexible piezoelectric cantilever arm and a fixed friction layer pasted on the inner surface of the frame. The moving friction layer and the fixed friction layer can periodically contact and separate within the frame.

The frame is fixed at its end by a gasket and a flexible piezoelectric cantilever arm, and an electrode layer is pasted between the frame and the fixed friction layer.

Wherein, the blade is connected in parallel with the free end of the flexible piezoelectric cantilever arm through a hinge.

Preferably, the moving friction layer is a metal friction layer, which is symmetrically pasted on the upper and lower surfaces of the flexible piezoelectric cantilever arm, and the fixed friction layer is a polydimethylsiloxane friction layer, which has a plurality of pyramidal microstructure friction units.

The shape of the blade can be square, rectangular, circular, or rhombus, and the shapes can be various, and are not limited to any one of these four shapes. The frame is a bluff body structure, which can be double-curved or shuttle-shaped, and can have various shapes, and it is not limited to any one of the two shapes.

The technical solutions of the present invention will be clearly and completely described below through specific embodiments. Apparently, the described embodiments are only some of the embodiments of the present invention, but not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

See Fig. 1: blade type composite wind energy harvester, including piezoelectric energy harvesting module and frictional energy harvesting module, piezoelectric energy harvesting module includes blade 7 and flexible piezoelectric cantilever arm 3, blade 7 and flexible piezoelectric cantilever arm 3 The free ends of the piezoelectric cantilever arm 3 are connected in parallel through hinges, and the connection method is not limited. The blade 7 can better respond to the disturbance of the wind fluid. Driven by the wind, the blade 7 can drive the flexible piezoelectric cantilever arm 7 in the frame. Periodic vibration occurs in 1, so that the flexible piezoelectric cantilever 7 is deformed to realize electric energy output. The shape of the blade is not limited, and the existence of the blade improves the amplitude of the flexible piezoelectric cantilever, thereby also improving the output of the piezoelectric voltage. strength.

The frictional energy harvesting module includes a moving friction layer 6 pasted on the surface of the flexible piezoelectric cantilever arm 3 and a fixed friction layer 5 pasted on the inner surface of the frame 1. The moving friction layer 6 and the fixed friction layer 5 can be periodically Relative contact and separation to convert wind energy into electrical energy.

The two energy harvesting methods of piezoelectric energy harvesting and frictional energy harvesting work simultaneously to improve the energy density output of the wind energy harvester in a low wind speed environment.

The frame 1 of the collector is a bluff body structure, and can be a double-arc or shuttle-shaped structure, which reduces the resistance of the airflow and ensures the stability of the airflow. At the same time, the design of the arc-shaped inner wall improves the friction between the moving friction layer 6 and the fixed friction layer. The contact area of 5 makes the moving friction layer 6 and the fixed friction layer 5 fully fit and squeeze when they collide, so as to improve the friction voltage output. The frame 1 is fixed at its end by the gasket 2 and the flexible piezoelectric cantilever arm 3 , and the electrode layer 4 is pasted between the fixed friction layer 5 .

The vibration of the flexible piezoelectric cantilever beam 3 is mainly caused by the Karman vortex street effect. Karman vortex street is an important phenomenon in fluid mechanics. Under certain conditions, when the fluid bypasses the bluff body, double-row vortices with opposite directions and regular arrangement will periodically fall off on both sides behind the bluff body. In this collector, when the wind blows through the frame 1 of the double arc-shaped flow blocking structure from the direction shown in Figure 2, the two sides of the blade 7 will produce a vortex 8 in the opposite direction and an air pressure difference, thereby forming a vortex 8 perpendicular to the blade 7 The pressure drives it to vibrate up and down, and the vibration of the blade 7 will drive the flexible piezoelectric cantilever beam 3 connected to it to vibrate with a relatively large amplitude. The flexible piezoelectric cantilever beam 3 will generate a voltage output due to deformation. At the same time, when the flexible piezoelectric cantilever beam 3 vibrates, it will drive the fixed friction layer 5 to periodically collide with the moving friction layer 6. The moving friction layer 6 is preferably a metal friction layer, and the fixed friction layer 5 is preferably a plurality of pyramid microstructures evenly distributed. Polydimethylsiloxane friction layer for structural friction units. According to the principles of friction electrification and electrostatic induction, the mutual contact and separation of two friction materials will generate electric energy output. The contact area when the two friction materials collide is the key factor affecting the friction output. The double arc structure frame of this collector 1 It can fully fit the friction layer when it collides, thereby increasing the voltage output.

Charge transfer occurs during periodic collisions between the polydimethylsiloxane friction layer and the metal friction layer, and its working principle is based on the coupling effect of triboelectric generation and electrostatic induction. Driven by the wind, the metal friction layer pasted on the surface of the flexible piezoelectric cantilever 3 periodically collides with the polydimethylsiloxane friction layers on the upper and lower sides. The metal friction layer is easy to lose electrons, and the polydimethylsiloxane friction layer is easy to gain electrons. The change of the potential difference during the process of contacting and separating the two will drive the transfer of electrons to the external circuit, thereby forming an alternating current output, as shown in Figure 3.

At the same time, the output performance test of the blade-type composite wind energy harvester is carried out in the wind tunnel equipment, which can provide a stable wind speed of 0m/s to 15m/s. The voltage output of the friction energy harvesting part and the piezoelectric energy harvesting part are shown in Figure 4. When the wind speed is lower than 4m/s, the flexible piezoelectric cantilever beam 3 hardly vibrates, so the two parts have no voltage output. When the wind speed is greater than 4m/s, as the wind speed increases, the voltage output of the two parts increases approximately linearly. When the wind speed is 10m/s, the peak output voltages of the piezoelectric and friction parts are 16V and 13.4V, respectively.

The invention provides a blade-type composite wind energy collector, which improves the energy output density by combining friction and piezoelectric energy collection modules. Adding the blade at the end of the flexible piezoelectric cantilever arm can better respond to the disturbance of the wind fluid, and improve the amplitude and piezoelectric voltage output of the piezoelectric energy harvesting part. The design of the frame's double-arc bluff body structure increases the contact area of each friction layer, thereby increasing the output of the friction voltage.

The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (7)

1. A blade-type composite wind energy harvester, characterized in that: comprising a piezoelectric energy harvesting module and a frictional energy harvesting module; The piezoelectric energy harvesting module includes a blade and a flexible piezoelectric cantilever; the blade is connected to the free end of the flexible piezoelectric cantilever, and the blade can drive the flexible piezoelectric cantilever to periodically vibrate in the frame; The frictional energy harvesting module includes a moving friction layer pasted on the surface of the flexible piezoelectric cantilever arm and a fixed friction layer pasted on the inner surface of the frame; the moving friction layer and the fixed friction layer can be in periodic relative contact with each other in the frame separation; The frame is fixed at the end of the frame and the flexible piezoelectric cantilever arm through gaskets; an electrode layer is pasted between the frame and the fixed friction layer. 2. A blade-type composite wind energy harvester according to claim 1, characterized in that: the blade is connected in parallel with the free end of the flexible piezoelectric cantilever arm through a hinge. 3. A blade-type composite wind energy harvester according to claim 1, characterized in that: the moving friction layer is a metal friction layer, which is symmetrically pasted on the upper and lower surfaces of the flexible piezoelectric cantilever arm. 4. A blade type composite wind energy collector according to claim 1, characterized in that: said fixed friction layer is a polydimethylsiloxane friction layer with a plurality of pyramidal microstructure friction units. 5 . The blade-type composite wind energy collector according to claim 1 , wherein the shape of the blades can be square, rectangular, circular, or rhombus. 6. The blade-type composite wind energy collector according to claim 1, wherein the frame is a bluff body structure. 7. The blade type composite wind energy collector according to claim 6, characterized in that: the shape of the frame is double arc or shuttle.