阅读说明：本技术 一种风致振压电俘能器 (Wind-induced vibration piezoelectric energy harvester ) 是由 张忠华 林仕杰 罗素清 吴鸣 张昱 任泽峰 程光明 于 2019-05-18 设计创作，主要内容包括：本发明涉及一种风致振压电俘能器,属新能源技术领域。支架的横梁上下两端分别设有带滑道的上下梁；耦合器的钝体上下两端都设有耳板,两个耳板内侧经圆柱体连接、外侧都设有半轴,圆柱体上设有两个相互平行的柱平面,圆柱体及两个耳板上设有相互连通的通槽；圆柱销的两端和两个半轴经轴套装在上下梁的滑道内；簧片的一端置于通槽内并经螺钉固定在耳板上、另一端经圆柱销的窄缝穿过；两个挡板的连接耳经螺钉分别装在上下梁上且其弧形板经钝体和圆柱体间的缝隙穿过后相接触；由基板和压电片构成的压电振子一端经螺钉和限形架的压板安装在横梁上、自由端顶靠在柱平面上；限形架的压板两端都设有带限形面的限形块,压电振子固定端的基板与限形面接触。(The invention relates to a wind-induced vibration piezoelectric energy harvester, and belongs to the technical field of new energy. The upper end and the lower end of a cross beam of the bracket are respectively provided with an upper beam and a lower beam with a slideway; the upper end and the lower end of the blunt body of the coupler are provided with lug plates, the inner sides of the two lug plates are connected through a cylinder, the outer sides of the two lug plates are provided with half shafts, the cylinder is provided with two parallel column planes, and the cylinder and the two lug plates are provided with through grooves which are communicated with each other; two ends of the cylindrical pin and two half shafts are sleeved in the slide ways of the upper beam and the lower beam through shafts; one end of the reed is arranged in the through groove and fixed on the lug plate through a screw, and the other end of the reed penetrates through a narrow slit of the cylindrical pin; the connecting lugs of the two baffles are respectively arranged on the upper beam and the lower beam through screws, and the arc-shaped plates of the two baffles are contacted after passing through a gap between the blunt body and the cylinder; one end of a piezoelectric vibrator consisting of a substrate and a piezoelectric sheet is arranged on the beam through a screw and a pressing plate of the shape limiting frame, and the free end of the piezoelectric vibrator abuts against the column plane; and both ends of a pressure plate of the shape limiting frame are provided with shape limiting blocks with shape limiting surfaces, and a substrate at the fixed end of the piezoelectric vibrator is contacted with the shape limiting surfaces.)

1. The wind-induced vibration piezoelectric energy harvester is characterized in that: the upper and lower ends of the cross beam of the bracket are respectively provided with an upper beam and a lower beam, the inner walls of the upper beam and the lower beam are provided with slideways, and the two ends of the lower beam are provided with support legs; the upper end and the lower end of the blunt body of the coupler are provided with lug plates, the inner sides of the two lug plates are connected through a cylinder, the outer sides of the two lug plates are provided with half shafts, the half shafts are coaxial with the cylinder, the axial lead of the half shafts is parallel to the axis of the blunt body, the cylinder is provided with two parallel column planes, and the cylinder and the two lug plates are provided with mutually communicated through grooves; the two ends of the cylindrical pin and the two half shafts are sleeved with shaft sleeves, and the shaft sleeves are arranged in the slide ways of the upper beam and the lower beam through screws; the cylindrical pin is arranged close to the cross beam, and a narrow slit is arranged at the axis of the middle section of the cylindrical pin; one end of the reed is arranged in the through groove and fixed on the lug plate through a screw, and the other end of the reed penetrates through the narrow slit; the baffle plates are composed of arc plates and connecting lugs, the connecting lugs of the two baffle plates are respectively installed on the upper beam and the lower beam through screws, the arc plates of the two baffle plates are propped against each other after penetrating through a gap between the blunt body and the cylinder, and the convex surfaces of the arc plates are installed close to the blunt body; one end of the piezoelectric vibrator is arranged on the beam through a screw and a pressing plate of the shape limiting frame, the piezoelectric vibrator is formed by bonding a substrate and a piezoelectric sheet, and one side of the substrate at the free end of the piezoelectric vibrator is abutted against the cylindrical plane of the cylinder; the two ends of the pressure plate of the shape limiting frame are provided with shape limiting blocks, and shape limiting surfaces are arranged on the shape limiting blocks; the distance between the two limiting blocks on the same limiting frame is wider than that of the piezoelectric sheet and narrower than that of the substrate, and the substrate at the fixed end of the piezoelectric vibrator is in contact with the limiting surface; the ratio of the total width of the arc-shaped plates to the diameter of the blunt body, namely the width-diameter ratio, of the two baffles after installation is 1-3, and the ratio of the minimum distance between the outer surface of the blunt body and the surface of the arc-shaped plate to the diameter of the blunt body, namely the diameter-diameter ratio, is 0-3.

Technical Field

The invention belongs to the technical field of new energy, and particularly relates to a wind-induced vibration piezoelectric energy harvester.

Background

In recent years, with the gradual maturity of wireless sensor network technology and the popularization of the wireless sensor network technology in the fields of environmental monitoring, health monitoring of large buildings and bridges, industry, military, public safety and the like, the research of micro wind power harvesters providing continuous energy supply for the micro wind power harvesters is widely concerned by domestic and foreign scholars. The micro-miniature wind energy harvester proposed at present is based on the electromagnetic principle and the piezoelectric principle basically, and is more suitable for wireless systems such as wireless network nodes and the like because the piezoelectric energy harvester cannot generate electromagnetic interference in the power generation process. The existing wind energy harvester utilizing a thin-sheet type piezoelectric vibrator structure mainly comprises two main types: the first is a blowing excitation type, namely, the piezoelectric vibrator is directly blown by wind power to generate bending deformation and generate electricity; the second is a rotary excitation type, namely, firstly, wind is utilized to rotate the blade, and then the blade drives the rotating mechanism to stir the piezoelectric vibrator to bend and deform and generate electricity. The common characteristic of the piezoelectric energy harvester is that the inertia force of the end mass of the piezoelectric vibrator is directly utilized to make the piezoelectric vibrator bend and deform and generate electricity, and the main disadvantages are as follows: the wind speed adaptability is poor, the effective wind speed range is small, the piezoelectric vibrator deforms in two directions, the piezoelectric sheet bears the alternating tensile stress action and lacks necessary shape limiting measures, and the adjustable range of the scale of the piezoelectric vibrator and the inherent frequency of the system is small.

Disclosure of Invention

The invention provides a wind-induced vibration piezoelectric energy harvester, which adopts the following implementation scheme: the upper and lower ends of a cross beam of the bracket are respectively provided with an upper beam and a lower beam, the upper beam and the lower beam are arranged on the upper side and the lower side of the cross beam in parallel and symmetrically, the upper beam and the lower beam are perpendicular to the cross beam, the inner walls of the upper beam and the lower beam are both provided with a slideway, and the two ends of the lower beam are provided with support legs; the upper end and the lower end of a blunt body of the coupler are provided with lug plates, the blunt body is a hollow shell, the inner sides of the two lug plates are connected through a cylinder, the outer sides of the two lug plates are provided with half shafts, the half shafts are coaxial with the cylinder, the axial lead of the half shafts is parallel to the axial lead of the blunt body, the cylinder is provided with two parallel column planes, the cylinder and the two lug plates are provided with mutually communicated through grooves, and the planes of the two column planes and the through grooves, where the axial leads of the half shafts and the blunt body are located, are taken as symmetrical central planes; the two ends of the cylindrical pin and the two half shafts are sleeved with shaft sleeves, and the shaft sleeves are arranged in the slide ways of the upper beam or the lower beam through screws; the cylindrical pin is arranged close to the cross beam, a narrow slit is arranged at the axis of the middle section of the cylindrical pin, and the axis of the cylindrical pin is positioned in the symmetrical central plane of the narrow slit; one end of the reed is arranged in the through groove and fixed on the lug plate through a screw, and the other end of the reed is fixed with the cylindrical pin through the screw after penetrating through the narrow slit; the baffle plates are composed of arc plates and connecting lugs, the connecting lugs of the two baffle plates are respectively installed on the upper beam and the lower beam through screws, the arc plates of the two baffle plates are propped against each other after penetrating through a gap between the blunt body and the cylinder, and the convex surfaces of the arc plates are installed close to the blunt body; one end of the piezoelectric vibrator is arranged on the beam through a screw and a pressing plate of the shape limiting frame, the piezoelectric vibrator is formed by bonding a substrate and a piezoelectric sheet, one side of the substrate at the free end of the piezoelectric vibrator is abutted against the column plane of the cylinder, and the substrate is in mutual contact with the column plane but has no acting force; the two ends of a pressure plate of the limiting frame are provided with limiting blocks, limiting surfaces are arranged on the limiting blocks, the limiting surfaces are arc surfaces, and the limiting surfaces are tangent to the surfaces, which are contacted with the piezoelectric vibrators, of the pressure plate; the distance between the two limiting blocks on the same limiting frame is wider than that of the piezoelectric sheet and narrower than that of the substrate, and the substrate at the fixed end of the piezoelectric vibrator is in contact with the limiting surface; when the reed is not in work, the symmetrical central layer in the thickness direction of the reed, the axis of the blunt body and the contact surfaces of the two arc-shaped plates are positioned in the same vertical plane; the ratio of the total width of the arc-shaped plates to the diameter of the blunt body, namely the width-diameter ratio, of the two baffles after installation is 1-3, and the ratio of the minimum distance between the outer surface of the blunt body and the surface of the arc-shaped plate to the diameter of the blunt body, namely the diameter-diameter ratio, is 0-3.

In the invention, wind is blown to the baffle and the cross beam by the blunt body, the wind generates a Karman vortex street after flowing through the blunt body, the alternating generation and falling of the vortex can lead the pressure of the airflow at the front side and the rear side of the blunt body to be changed alternately, thus generating an exciting force which leads the coupler to swing in a reciprocating way, when the coupler swings, the piezoelectric vibrator is forced to bend and deform in the direction which leads the piezoelectric piece to bear the pressure stress, and the wind energy is converted into electric energy in the reciprocating bending deformation process of the piezoelectric vibrator; when wind passes through the bluff body and is blocked by the baffle, the flow direction, the vortex form and the dynamic characteristic are changed, so that the amplitude of the exciting force is changed, and the vibration amplitude is increased or reduced; when the oscillating amplitude of the bluff body reaches a rated value, the substrate at the free end of the piezoelectric vibrator is separated from the column plane and is in contact with the circular arc surface of the cylinder, and the deformation of the piezoelectric vibrator is not increased along with the increase of the amplitude of the bluff body: meanwhile, when the amplitude of the blunt body reaches a rated value, the substrate of the piezoelectric vibrator is pressed on the limiting surface through the circular arc surface of the cylinder, and the compressive stress of each point in the length direction of the piezoelectric sheet is equal and smaller than the allowable value, so that the piezoelectric vibrator has higher power generation capacity and higher reliability.

According to the invention, the distance between the cylindrical pin and the cylinder can be adjusted by adjusting the shaft sleeve positions at the two ends of the cylindrical pin, the minimum distance between the arc-shaped plate and the outer surface of the blunt body can be adjusted by adjusting the mounting position of the baffle, and the bending rigidity of the reed can be changed by changing the distance between the cylindrical pin and the cylinder, so that the fundamental frequency of a vibration system formed by the blunt body and the reed, namely the fundamental frequency of the energy harvester is changed, and the fundamental frequency of the energy harvester is adapted to the vortex-induced vibration frequency to realize resonance; the aspect ratio can be adjusted by changing the minimum distance from the arc-shaped plate to the outer surface of the bluff body, so that the effective control of the amplitude of the bluff body is realized, even if the amplitude is increased or reduced.

In the invention, the thickness of the substrate is equal to that of the piezoelectric sheet, and the radius of the limiting surface is

The allowable deformation of the free end of the piezoelectric vibrator when the shape limiting surface is not used is

Wherein l is the cantilever length of the piezoelectric vibrator, h is the total thickness of the piezoelectric vibrator, β ═ E_m/E_p，E_mAnd E_pThe modulus of elasticity, T, of the substrate and piezoelectric sheet material, respectively_pAnd k₃₁Respectively, the allowable stress and the electromechanical coupling coefficient of the piezoelectric sheet material.

The piezoelectric energy harvester has the advantages and characteristics that ① is easy to change the natural frequency of the energy harvester through the rigidity adjustment of the reed, so that the natural frequency of the energy harvester is adaptive to vortex-induced vibration frequency, the response characteristic and the power generation capacity are improved, the baffle arranged behind the ② bluff body can effectively adjust the coupling vibration response characteristic of the bluff body, the needed bluff body vibration amplification ratio, flow rate adaptability and power generation capacity are easy to obtain through adjusting the distance, the scale and other parameters of the bluff body, the ③ piezoelectric vibrator is in unidirectional bending deformation, the deformation amount is controllable, the stress distribution is uniform, and therefore the power generation capacity is strong, and the reliability.

Drawings

FIG. 1 is a schematic diagram of an energy harvester according to a preferred embodiment of the invention;

FIG. 2 is a cross-sectional view A-A of FIG. 1;

FIG. 3 is a schematic structural view of a restraint frame according to a preferred embodiment of the present invention;

FIG. 4 is a top view of FIG. 3;

FIG. 5 is a schematic diagram of a cylindrical pin according to a preferred embodiment of the present invention;

FIG. 6 is a top view of FIG. 5;

FIG. 7 is a schematic structural view of a bracket according to a preferred embodiment of the present invention;

FIG. 8 is a right side view of FIG. 7;

FIG. 9 is a schematic diagram of the structure of a coupler in accordance with a preferred embodiment of the present invention;

FIG. 10 is a top view of FIG. 9;

FIG. 11 is a schematic view of the structure of the baffle in the present invention and preferred embodiment;

fig. 12 is a right side view of fig. 11.

Detailed Description

The upper end and the lower end of a cross beam a3 of the bracket a are respectively provided with an upper beam a1 and a lower beam a2, the upper beam a1 and the lower beam a2 are arranged on the upper side and the lower side of the cross beam a3 in parallel and symmetrically, the upper beam a1 and the lower beam a2 are perpendicular to the cross beam a3, the inner walls of the upper beam a1 and the lower beam a2 are both provided with a slideway a4, and the two ends of the lower beam a2 are provided with supporting legs a 5: ear plates e2 are arranged at the upper end and the lower end of a blunt body e1 of the coupler e, the blunt body e1 is a hollow shell, the inner sides of the two ear plates e2 are connected through a cylinder e3, half shafts e4 are arranged at the outer sides of the two ear plates e2, the half shafts e4 and the cylinder e3 are coaxial, the axial line of the half shafts e is parallel to the axial line of the blunt body e1, two parallel column planes e5 are arranged on the cylinder e3, mutually communicated through grooves e6 are arranged on the cylinder e3 and the two ear plates e2, and the planes of the two column planes e5 and the through grooves e6, on which the axial lines of the half shafts e4 and the e1 of the blunt body are located, are used as; two ends of a cylindrical pin g and two half shafts e4 are sleeved with shaft sleeves f, and the shaft sleeves f are arranged in a slide way a4 of an upper beam a1 and a lower beam a2 through screws; the cylindrical pin g is arranged close to the cross beam a3, a narrow slit g1 is arranged at the axis of the middle section of the cylindrical pin g, and the axis of the cylindrical pin g is positioned in the symmetrical central plane of the narrow slit g 1; one end of the reed c is arranged in the through groove e6 and fixed on the lug plate e2 through a screw, and the other end of the reed c is fixed with the cylindrical pin g through a screw after penetrating through the narrow slit g 1; the baffle plate h is composed of an arc-shaped plate h1 and connecting lugs h2, the connecting lugs h2 of the two baffle plates h are respectively installed on an upper beam a1 and a lower beam a2 through screws, the arc-shaped plates h1 of the two baffle plates h are propped against each other after passing through a gap between a blunt body e1 and a cylinder e3, and the convex surfaces of the arc-shaped plates h1 are installed close to a blunt body e 1; one end of a piezoelectric vibrator d is arranged on a beam a3 through a screw and a pressure plate k1 of a shape limiting frame k, the piezoelectric vibrator d is formed by bonding a substrate d1 and a piezoelectric sheet d2, one side of the substrate d1 at the free end of the piezoelectric vibrator d abuts against a column plane e5 of a cylinder e3, and the substrate d1 and the column plane e5 are in mutual contact but have no acting force; two ends of a pressure plate k1 of the limiting frame k are provided with limiting blocks k2, limiting blocks k2 are provided with limiting surfaces k3, the limiting surfaces k3 are arc surfaces, and the surfaces, which are contacted with the piezoelectric vibrator d, of the limiting surfaces k3 and the pressure plate k1 are tangent; the distance between two limiting blocks k2 on the same limiting frame k is wider than that of a piezoelectric sheet d2 and narrower than that of a substrate d1, and a substrate d1 at the fixed end of a piezoelectric vibrator d is in contact with a limiting surface k 3; when the reed is not in work, the symmetrical central layer in the thickness direction of the reed c, the axis of the blunt body e1 and the contact surfaces of the two arc-shaped plates h1 are positioned in the same vertical plane, namely the horizontal plane z in the figure 2; after the two baffles H are installed, the ratio of the total width H of the arc-shaped plates H1 to the diameter D of the blunt body e1, namely the width-to-diameter ratio H/D, is 1-3, and the ratio of the minimum distance L between the outer surface of the blunt body e1 and the surface of the arc-shaped plate H1 to the diameter D of the blunt body e1, namely the distance-to-diameter ratio L/D, is 0-3.

In the invention, wind is blown to a baffle plate h and a cross beam a3 by a bluff body e1, the wind generates a Karman vortex street after flowing through a bluff body e1, the alternating generation and falling of the vortex can lead the wind pressure on the front side and the rear side of the bluff body e1 to be changed alternately, thus generating an excitation force which enables a coupler e to swing in a reciprocating way, when the coupler e swings, a piezoelectric vibrator d is forced to bend and deform towards the direction which enables a piezoelectric sheet d2 to bear the pressure stress, and the wind energy is converted into electric energy in the reciprocating bending deformation process of the piezoelectric vibrator d; wind flows to and swirl form and dynamic characteristic all change when receiving baffle h's hindrance behind bluff body e1 to make the amplitude of exciting force change, vibration amplitude increases or reduces: when the swinging amplitude of the bluff body e1 reaches a rated value, the substrate d1 at the free end of the piezoelectric vibrator d is separated from the column plane e5 and is in contact with the arc surface of the cylinder e3, and the deformation of the piezoelectric vibrator d is not increased along with the increase of the amplitude of the bluff body e 1; meanwhile, when the amplitude of the blunt body e1 reaches a rated value, the substrate d1 of the piezoelectric vibrator d is pressed against the plane k3 through the arc surface of the cylinder e3, and the compressive stress of each point in the length direction of the piezoelectric sheet d2 is equal and smaller than the allowable value, so that the piezoelectric vibrator has high power generation capacity and high reliability.

In the invention, the distance between the cylindrical pin g and the cylinder e3 can be adjusted by adjusting the positions of shaft sleeves f at the two ends of the cylindrical pin g, the minimum distance L between the arc-shaped plate h1 and the outer surface of the bluff body e1 can be adjusted by adjusting the mounting position of the baffle plate h, and the bending rigidity of the reed c can be changed by changing the distance between the cylindrical pin g and the cylinder e3, so that the fundamental frequency of a vibration system, namely the energy harvester, formed by the bluff body e1 and the reed c is changed, so that the fundamental frequency of the energy harvester is adapted to the vortex-induced vibration frequency, and resonance is realized; the aspect ratio can be adjusted by changing the minimum distance L between the arc-shaped plate h1 and the outer surface of the bluff body e1, and the effective control of the amplitude of the bluff body e1 is realized, namely the amplitude is increased or reduced.

In the invention, the thickness of the substrate d1 is equal to that of the piezoelectric sheet d2, and the radius of the shape limiting surface k3 is

When the shape-limiting surface is not used, the allowable deformation of the free end of the piezoelectric vibrator d is

Wherein l is the cantilever length of the piezoelectric vibrator d, h is the total thickness of the piezoelectric vibrator d, β ═ E_m/E_p，E_mAnd E_pThe elastic moduli, T, of the materials of the substrate d1 and the piezoelectric sheet d2_pAnd k₃₁The allowable stress and electromechanical coupling coefficient of the piezoelectric sheet d2 material, respectively.