Magnetic-force-electric coupling energy collector and method based on asymmetric torsional mode

Abstract

The invention relates to a magnetism-force-electricity coupling energy collector and method based on an asymmetric torsional mode, and belongs to the technical field of energy collection. The asymmetric bending beam piezoelectric transducer comprises a piezoelectric plate, an asymmetric bending beam structure, a mass block and a fixing screw rod, the polarization direction of the piezoelectric plate is arranged along the thickness direction, electrode coatings are arranged on two side surfaces of the piezoelectric plate along the thickness direction, the electrode coatings on the two side surfaces are defined as a bonding electrode surface and a leading-out electrode surface respectively, the asymmetric bent beam structure comprises a main beam, a long limb and a short limb which are arranged in an integrated structure, and the main beam is arranged on the main beam. A fixing hole is formed in the middle of the main beam, the bonding electrode faces are bonded and fixed to the main beam through epoxy resin and distributed on the left side and the right side of the fixing hole, the leading-out electrode faces lead out electrical signals through wires, and the mass block is fixed to the asymmetric bent beam structure through magnetic force. One end of the fixing screw rod is connected with the fixing hole, and the fixing screw rod is installed on the rigid base.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy collection devices, and in particular relates to a magnetic-mechanical-electrical coupling energy collector and method based on an asymmetric torsional mode. Background Art

[0002] In recent years, with the continuous advancement of Internet of Things technology and digital system integration technology, small wireless sensor devices, portable electronic devices and small wearable devices have developed rapidly. At present, these microelectronic devices generally rely on non-clean energy such as chemical batteries for power supply, and the replacement of batteries will increase the cost of equipment use. Therefore, energy harvesting technology that collects clean energy such as heat, light, magnetic energy and mechanical vibration from the natural environment has become a current research hotspot. Among many renewable energy sources, energy harvesting technology for ubiquitous mechanical vibration energy and stray magnetic field energy with a frequency of 50 / 60 Hz around energized cables has received widespread attention. It is not restricted by region, time and weather, and is widely used in infrastructure, electronic equipment and factory construction. The magnetic-mechanical-electric coupled energy harvester can couple the energy harvesting of vibration energy and stray magnetic field. Compared with a single energy harvesting technology, it has the advantages of diverse application scenarios, high energy density, and convenient integration, and has broad application prospects.

[0003] The two Chinese invention patents, "A multi-directional broadband piezoelectric energy collector" and "A multi-layer cascaded magnetic-mechanical-electromagnetic field energy collector and its manufacturing method", with publication numbers CN112187098A and CN117277868A respectively, explain the current technical solutions in the field of magnetic-mechanical-electric coupled energy collectors. The mainstream magnetic-mechanical-electric coupled energy collector designs on the market currently mostly adopt a single-end clamped cantilever beam structure. When collecting vibration energy, the vibration signal is applied to the clamping end of the cantilever beam structure, and the permanent magnet mass block located at the free end of the cantilever beam drives the cantilever beam to complete the tensile and bending deformation process, which makes the piezoelectric material work in the tensile and bending mode, that is, it completes the telescopic deformation in the length direction and generates charges in the thickness direction. By collecting the charge signal on the surface of the piezoelectric sheet, the force-to-electric conversion process can be completed; when collecting magnetic field energy, the alternating magnetic field signal will act on the permanent magnet at the free end of the cantilever beam. Since there is an angle between the direction of the alternating magnetic field and the magnetization direction of the permanent magnet, the permanent magnet will be affected by the alternating magnetic force, which will cause a magnetic torque to be generated at the end of the cantilever beam, and the magnetic torque will drive the cantilever beam to complete the tensile and bending deformation process, which makes the piezoelectric material in the tensile and bending mode. By collecting the charge signal on the surface of the piezoelectric sheet, the magneto-electric conversion process can be completed.

[0004] In this way, the energy collector composed of the traditional single-end clamped cantilever beam structure only utilizes the deformation in the length direction of the piezoelectric material, which is difficult to achieve high power output. It has the disadvantages of only microampere output current and microwatt output power density, which is particularly limited in practical industrial applications. At the same time, in the process of energy collection, the traditional single-end clamped cantilever beam structure energy collector is often accompanied by clamping loss, which leads to lower energy collection efficiency. The vibration mode of the traditional cantilever beam structure is mainly based on the first or second order bending mode in the length direction. Compared with the asymmetric bending beam, the space occupied in the length direction is also relatively large, which is not conducive to installation and use in a narrow space. In addition, the structure also has problems such as a single resonant frequency point and a narrow output bandwidth, which makes it difficult to reach a resonant state in practical applications, thereby further reducing the energy output efficiency. When the mainstream multi-beam broadband energy collector is electrically connected in series and parallel, there will be a phase difference between different signals, which will cause the positive and negative charges to cancel each other and reduce the output power. This not only hinders the development of magnetic-mechanical-electric energy collectors towards broadband output, but also increases the challenge of building a more compact and miniaturized structure. Summary of the invention

[0005] The purpose of the present invention is to overcome the above-mentioned deficiencies in the prior art and to provide a magnetic-mechanical-electric coupling energy collector and method based on an asymmetric torsional mode with a reasonable structural design, so as to overcome the problems in the prior art such as low energy collection efficiency, low output power density, narrow output bandwidth, non-compact structure and difficulty in miniaturization for application in limited local space.

[0006] The technical solution adopted by the present invention to solve the above-mentioned problem is: the magnetic-mechanical-electric coupling energy collector based on the asymmetric torsional mode has the following structural features: it includes piezoelectric sheets with polarization directions in the same or opposite directions to realize the series or parallel connection of electrical signals, an asymmetric bent beam structure that enables the piezoelectric sheets to work in a torsional mode to realize energy output power, a mass block for realizing energy collection, and a fixing screw for mounting the asymmetric bent beam structure on a rigid base; the polarization direction of the piezoelectric sheet is arranged along the thickness direction, and the thickness direction of the piezoelectric sheet is arranged along the thickness direction of the piezoelectric sheet. Both sides are provided with electrode coatings, and the electrode coatings on the two sides are defined as bonding electrode surfaces and lead-out electrode surfaces respectively. The asymmetric bent beam structure includes a main beam, a long limb and a short limb arranged in an integrated structure. A fixing hole is arranged in the middle of the main beam. The bonding electrode surface is bonded and fixed to the main beam by epoxy resin and is distributed on the left and right sides of the fixing hole. The lead-out electrode surface leads out the electrical signal through a wire. The mass block is fixed to the asymmetric bent beam structure by magnetic force. One end of the fixing screw is connected to the fixing hole, and the fixing screw is installed on a rigid base. The location and quantity of the piezoelectric sheet can be configured according to the service scenario requirements, and the number of mass blocks can be designed in different directions according to the service scenario requirements to achieve the application flexibility of the energy collector unit.

[0007] Furthermore, the material of the piezoelectric sheet is lead zirconate titanate (PZT) piezoelectric ceramic, bismuth scandate-lead titanate (BS-PT) piezoelectric ceramic, barium titanate (BaTiO3) piezoelectric ceramic, potassium sodium niobate (KNN) piezoelectric ceramic, lead magnesium niobate-lead titanate (PMN-PT) piezoelectric single crystal or lead zinc niobate-lead titanate (PZN-PT) piezoelectric single crystal material. The materials of the piezoelectric sheet selected include but are not limited to the above.

[0008] Furthermore, the mass block is made of a metal block or a permanent magnet, wherein the N and S poles of the permanent magnet are connected facing each other and fixed at the ends of the long limb and the short limb by the magnetic force between them. The designed position of the mass block can be flexibly changed, which can adjust the resonant frequency of the energy collector without changing the asymmetric bending beam structure; and according to the needs of the service scenario, the magnetization direction of the magnet is reasonably adjusted to meet the energy collection needs of different service scenarios, which improves the flexibility of the energy collector and the adaptability to the service scenario.

[0009] Furthermore, the asymmetric bent beam structure refers to a beam structure that is asymmetrically bent or folded in its length direction, and the asymmetric bent beam structure is made of beryllium bronze or stainless steel, which is a material with a high elastic modulus. This design can change the stress distribution, deformation characteristics and vibration mode of the beam, so that the piezoelectric piece is in a torsional mode under the excitation of the vibration source, which helps to improve the output power of the energy collector; the design of different asymmetric bent beam structures can change the direction of the principal stress, thereby completing the diversification of the torsional mode of the piezoelectric piece; in addition, the asymmetric bent beam structure design adopts a torsional vibration mode, which is smaller in length than the traditional cantilever beam structure, and also helps to miniaturize the device, ensuring that the energy collector unit works effectively and efficiently within the preset space range.

[0010] Furthermore, one end of the fixing screw passes through the fixing hole, and the asymmetric bent beam structure is fixed by point clamping, and the other end of the fixing screw is fixed on the rigid base. During the process of magneto-electric or force-electric conversion of the energy collector unit, the bent beam structures on the left and right sides of the fixing screw keep the fixing center almost stationary under opposite torques, which avoids energy loss caused by clamping loss to the greatest extent.

[0011] Furthermore, the main beam, long limbs and short limbs are arranged in a rectangular or trapezoidal structure.

[0012] Furthermore, the piezoelectric sheet is arranged in a square or circular structure.

[0013] A working method of a magnetic-mechanical-electric coupling energy collector based on an asymmetric torsional mode. When the energy collector causes the asymmetric bent beam structure to undergo periodic torsional deformation due to an external vibration signal or magnetic field signal, the piezoelectric film will be induced to undergo periodic deformation. The piezoelectric film will generate a periodic electrical signal on the surface based on the principle of the positive piezoelectric effect unique to piezoelectric materials. When the excitation frequency of the external vibration signal or magnetic field signal is consistent with the inherent resonant frequency of the energy collector, the vibration signal generated thereby is the largest, and energy collection will be more effective, thereby achieving higher energy conversion efficiency and output power.

[0014] Furthermore, when the energy collector is in the service scenario of force-electric conversion, according to the different frequencies of external vibration signals, the long limb co-directional vibration mode and the short limb co-directional vibration mode can be excited, that is, the two long limb parts vibrate up and down at the same time and the two short limb parts vibrate up and down at the same time, which ensures that the phase difference between the alternating electrical signals of the piezoelectric piece is fixed to zero; when the energy collector is in the service scenario of magneto-electric conversion, according to the different frequencies of external alternating magnetic fields, the long limb reverse vibration mode and the short limb reverse vibration mode can be excited, that is, the two long limb parts vibrate up and down and the two short limb parts vibrate up and down, which ensures that the phase difference between the alternating electrical signals of the piezoelectric piece is fixed to half a cycle. Whether the energy collector is in the co-directional vibration mode in the force-electric conversion scenario or the reverse vibration mode in the magneto-electric conversion scenario, the series and parallel connection of electrical signals will be easier to design circuits due to the fixed phase difference.

[0015] Furthermore, when the energy collector works in a multi-unit matrix form, it includes multiple energy collectors that work independently of each other, and multiple energy collectors that work independently of each other are arranged in a matrix form, each of which can collect energy according to different magneto-electric conversion and force-electric conversion service scenario requirements, further adapting to broadband energy collection needs. Through the matrix layout, multiple energy collector units can be efficiently integrated, significantly reducing the size of the energy collector in terms of space occupation, which is particularly suitable for scenarios with narrow layout space; and this matrix design allows functions to be modularly expanded according to scenario requirements, facilitating later maintenance and upgrades.

[0016] Compared with the prior art, the present invention has the following advantages: 1. The asymmetric bent beam structure in the energy collector changes the traditional mode of stress on the piezoelectric sheet. It is no longer limited to a single length strain direction, but realizes the coupling of the length and thickness positive strain directions and the shear direction. Therefore, the deformation of the piezoelectric sheet is not limited to the positive strain direction, but the deformation in the shear direction is also effectively utilized. This ensures that the asymmetric bent beam structure can fully utilize the torsional mode of the piezoelectric sheet, thereby significantly enhancing the output power of the energy collector.

[0017] 2. The fixing screw is used with bolts to fix the energy collector to a rigid base through a fixing hole in the center of the asymmetric bent beam structure. During the magneto-electric conversion process of the energy collector unit, the cantilever beam structures on the left and right sides of the fixing screw keep the fixing center nearly stationary under opposite magnetic torques, which minimizes energy loss caused by clamping loss.

[0018] 3. The piezoelectric sheets can be set in multiple locations, and the polarization directions of the piezoelectric sheets can be inconsistent, which can easily complete the electrical series connection and electrical parallel connection of the piezoelectric sheets; whether it is the same-direction vibration mode serving in the force-electric conversion scenario, or the reverse vibration mode serving in the magneto-electric conversion scenario, the series and parallel connection of electrical signals will greatly reduce the difficulty of series and parallel operation due to the fixed phase difference; therefore, according to the requirements of different application scenarios, a larger output current can be obtained through electrical parallel connection, or a larger output voltage can be obtained through electrical series connection, which further improves the flexibility of use of the energy harvester and the reliability of series and parallel connection.

[0019] 4. When there are multiple energy collectors and multiple energy collectors work in a multi-unit matrix form, the compact structural design can realize the characteristic design of each energy collector unit through matrix arrangement. Each unit can finely adjust the output frequency and output power according to the actual application scenario to fully meet various output bandwidth requirements. In addition, thanks to the matrix layout characteristics, the functions of the energy collector can be modularly expanded and conveniently maintained and upgraded according to user needs, reflecting excellent flexibility and scalability. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the structure of the magnetic-mechanical-electrical coupling energy harvester based on the asymmetric torsional mode of embodiments 1 and 2 of the present invention.

[0021] Figure 2 It is a schematic structural diagram of the asymmetric bent beam structure (rectangle) of embodiments 1 and 2 of the present invention.

[0022] Figure 3 It is a schematic diagram of the same-direction vibration mode of the long limb of Example 1 of the present invention.

[0023] Figure 4 It is a schematic diagram of the same-direction vibration mode of the short limb of Example 1 of the present invention.

[0024] Figure 5 It is a schematic structural diagram of the asymmetric bent beam structure (trapezoidal) of embodiments 1 and 2 of the present invention.

[0025] Figure 6 It is a schematic diagram of the structure of embodiments 1 and 2 of the present invention when multiple energy harvesters are arranged in a 5×5 matrix.

[0026] Figure 7 It is a schematic diagram of the reverse vibration mode of the long limb of Example 2 of the present invention.

[0027] Figure 8 It is a schematic diagram of the reverse vibration mode of the short limb of Example 2 of the present invention.

[0028] In the figure: piezoelectric sheet 101, asymmetric bending beam structure 102, mass block 103, fixing screw 104, Main beam 201, long limb 202, short limb 203. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only 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 should fall within the scope of protection of the present invention.

[0030] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0031] Example 1 (such as Figure 1-6 As shown), the energy harvester is a force-electric coupling energy harvester, which serves in the force-electric conversion scenario.

[0032] The magnetic-mechanical-electric coupling energy harvester based on the asymmetric torsional mode in this embodiment includes a piezoelectric sheet 101 with polarization directions in the same or opposite directions to realize the series or parallel connection of electrical signals, an asymmetric bent beam structure 102 that enables the piezoelectric sheet 101 to work in a torsional mode to realize energy output power, a mass block 103 for realizing energy harvesting, and a fixing screw 104 for mounting the asymmetric bent beam structure 102 on a rigid base; The piezoelectric sheet 101 in this embodiment is arranged in a square or circular structure, the polarization direction of the piezoelectric sheet 101 is arranged along the thickness direction, and electrode coatings are arranged on both sides of the piezoelectric sheet 101 along the thickness direction, and the electrode coatings on the two sides are defined as a bonding electrode surface and a lead-out electrode surface respectively. The asymmetric bent beam structure 102 includes a main beam 201, a long limb 202 and a short limb 203 arranged in an integrated structure, a fixing hole is arranged in the middle of the main beam 201, and the main beam 201, the long limb 202, and the short limb 203 are arranged in a rectangular or trapezoidal structure.

[0033] The bonding electrode surface in this embodiment is bonded and fixed to the main beam 201 by epoxy resin and is distributed on the left and right sides of the fixing hole. The lead-out electrode surface leads out the electrical signal through a wire. The mass block 103 is fixed to the asymmetric bent beam structure 102 by magnetic force. One end of the fixing screw 104 is connected to the fixing hole, and the fixing screw 104 is installed on a rigid base.

[0034] The material of the piezoelectric sheet 101 in this embodiment is lead zirconate titanate (PZT) piezoelectric ceramic, bismuth scandate-lead titanate (BS-PT) piezoelectric ceramic, barium titanate (BaTiO3) piezoelectric ceramic, potassium sodium niobate (KNN) piezoelectric ceramic, and lead magnesium niobate-lead titanate (PMN-PT) piezoelectric single crystal or lead zinc niobate-lead titanate (PZN-PT) piezoelectric single crystal material. The material of the piezoelectric sheet 101 includes but is not limited to the above-mentioned materials.

[0035] The mass block 103 in this embodiment is made of a metal block or a permanent magnet, wherein the N and S poles of the permanent magnet are connected facing each other and fixed at the ends of the long limb 202 and the short limb 203 by the magnetic force between them. The designed position of the mass block 103 can be flexibly changed, which can adjust the resonant frequency of the energy collector without changing the asymmetric bent beam structure 102; and, according to the needs of the service scenario, the magnetization direction of the magnet is reasonably adjusted to meet the energy collection needs of different service scenarios, which improves the flexibility of the energy collector and the adaptability to the service scenario.

[0036] The asymmetric bent beam structure 102 in this embodiment refers to a beam structure that has asymmetric bending or folding in its length direction. The asymmetric bent beam structure 102 is made of beryllium bronze or stainless steel, which is a material with a high elastic modulus. This design can change the stress distribution, deformation characteristics and vibration mode of the beam, so that the piezoelectric piece 101 is in a torsional mode under the excitation of the vibration source, which helps to improve the output power of the energy collector; the design of different asymmetric bent beam structures 102 can change the direction of the principal stress, thereby completing the diversification of the torsional mode of the piezoelectric piece 101; in addition, the asymmetric bent beam structure 102 design adopts a torsional vibration mode, which is smaller in length than the traditional cantilever beam structure, and also helps to miniaturize the device, ensuring that the energy collector unit works effectively and efficiently within the preset space range.

[0037] One end of the fixing screw 104 in this embodiment passes through the fixing hole, and fixes the asymmetric bent beam structure 102 by point clamping, and the other end of the fixing screw 104 is fixed on the rigid base. During the process of magneto-electric or force-electric conversion of the energy collector unit, the bent beam structures on the left and right sides of the fixing screw keep the fixing center almost still under opposite torques, which avoids energy loss caused by clamping loss to the greatest extent.

[0038] In this embodiment, when the energy collector causes the asymmetric bent beam structure 102 to undergo periodic torsional deformation due to an external vibration signal or magnetic field signal, the piezoelectric film 101 will be induced to undergo periodic deformation, and the piezoelectric film 101 will generate a periodic electrical signal on the surface based on the principle of the positive piezoelectric effect unique to piezoelectric materials; when the excitation frequency of the external vibration signal or magnetic field signal is consistent with the inherent resonant frequency of the energy collector, the vibration signal generated thereby is the largest, and energy collection will be more effective, thereby achieving higher energy conversion efficiency and output power.

[0039] In this embodiment, when the energy collector is in the force-electric conversion service scenario, according to the different frequencies of the external vibration signal, the same-direction vibration mode of the long limb 202 and the same-direction vibration mode of the short limb 203 can be excited, that is, the two long limbs 202 parts vibrate up and down at the same time and the two short limbs 203 parts vibrate up and down at the same time, which ensures that the phase difference between the alternating electrical signals of the piezoelectric sheet 101 is fixed to zero. Whether it is the same-direction vibration mode serving in the force-electric conversion scenario or the reverse vibration mode serving in the magneto-electric conversion scenario, the series and parallel connection of the electrical signal will be easier to design the circuit due to the fixed phase difference.

[0040] In this embodiment, when the energy collector works in a multi-unit matrix form, it includes multiple energy collectors that work independently of each other, and multiple energy collectors that work independently of each other are arranged in a matrix form, each of which can collect energy according to different magneto-electric conversion and force-electric conversion service scenario requirements, further adapting to broadband energy collection needs. Through the matrix layout, multiple energy collector units can be efficiently integrated, significantly reducing the size of the energy collector in terms of space occupation, which is particularly suitable for scenarios with narrow layout space; and this matrix design allows functions to be modularly expanded according to scenario requirements, facilitating later maintenance and upgrades.

[0041] Specifically, the energy harvester serves the needs of force-to-electricity conversion scenarios, and its structure is shown in the following figure. Figure 1 As shown, it includes a piezoelectric sheet 101, an asymmetric bending beam structure 102, a mass block 103, and a fixing screw 104; Figure 2 , wherein two piezoelectric sheets 101 are bonded to the main beam 201 on both sides of the fixing hole of the asymmetric bent beam structure 102 using epoxy resin, and their polarization directions can be different or the same; when the vibration table signal acts on the energy collector, the asymmetric bent beam structure 102 applies alternating torsional stress to the piezoelectric sheet 101, and an output electrical signal is generated due to the positive piezoelectric effect. The energy collector will have two resonant modes in the resonant state, such as Figure 3 (Long limb co-directional vibration mode) and Figure 4 (Short limb same-direction vibration mode).

[0042] The size parameters of the main beam 201, the long limb 202, and the short limb 203 in the asymmetric bent beam structure 102 are flexible and rich, and can be flexibly selected according to the actual application scenario, such as Figure 5 As shown, the main beam 201, the long limb 202 and the short limb 203 can adopt a rectangular design, or a trapezoidal design or other shaped structural designs to plan the stress distribution to adapt to the needs of different scenarios; especially when the main beam 201 adopts a trapezoidal structural design, its ends will produce a more uniform stress distribution. Compared with other structural designs, this design can give the energy collector a higher energy conversion efficiency.

[0043] In order to effectively improve the energy collection efficiency and adapt to the needs of different mission scenarios, multiple energy collector units need to be used in conjunction with each other. Here we take a 5×5 matrix arrangement of energy collectors as an example. Figure 6 As shown in the figure, a 5×5 matrix arrangement of energy harvesters is shown, in which each energy harvester unit can be independently controlled. Therefore, the resonant frequency and working mode of the energy harvester can be adjusted by designing energy harvesters with different size parameters. Figure 3 The same-direction vibration modes of the long limb and Figure 4 The asymmetric bent beam structure 102 design facilitates small-size assembly and dense arrangement to meet the broadband requirements of different scenarios or improve energy conversion efficiency; therefore, the entire energy collector matrix group has a simple structure, regular arrangement, small size, and easy maintenance, which is suitable for most energy collection scenario requirements.

[0044] Example 2 (such as Figure 1-2 , as shown in 5-8), the energy collector is a magneto-electric coupled energy collector, which serves in the magneto-electric conversion scenario.

[0045] The magnetic-mechanical-electric coupling energy harvester based on the asymmetric torsional mode in this embodiment includes a piezoelectric sheet 101 with polarization directions in the same or opposite directions to realize the series or parallel connection of electrical signals, an asymmetric bent beam structure 102 that enables the piezoelectric sheet 101 to work in a torsional mode to realize energy output power, a mass block 103 for realizing energy harvesting, and a fixing screw 104 for mounting the asymmetric bent beam structure 102 on a rigid base; The piezoelectric sheet 101 in this embodiment is arranged in a square or circular structure, the polarization direction of the piezoelectric sheet 101 is arranged along the thickness direction, and electrode coatings are arranged on both sides of the piezoelectric sheet 101 along the thickness direction, and the electrode coatings on the two sides are defined as a bonding electrode surface and a lead-out electrode surface respectively. The asymmetric bent beam structure 102 includes a main beam 201, a long limb 202 and a short limb 203 arranged in an integrated structure, a fixing hole is arranged in the middle of the main beam 201, and the main beam 201, the long limb 202, and the short limb 203 are arranged in a rectangular or trapezoidal structure.

[0046] The bonding electrode surface in this embodiment is bonded and fixed to the main beam 201 by epoxy resin and is distributed on the left and right sides of the fixing hole. The lead-out electrode surface leads out the electrical signal through a wire. The mass block 103 is fixed to the asymmetric bent beam structure 102 by magnetic force. One end of the fixing screw 104 is connected to the fixing hole, and the fixing screw 104 is installed on a rigid base.

[0047] The material of the piezoelectric sheet 101 in this embodiment is lead zirconate titanate (PZT) piezoelectric ceramic, bismuth scandate-lead titanate (BS-PT) piezoelectric ceramic, barium titanate (BaTiO3) piezoelectric ceramic, potassium sodium niobate (KNN) piezoelectric ceramic, lead magnesium niobate-lead titanate (PMN-PT) piezoelectric single crystal or lead zinc niobate-lead titanate (PZN-PT) piezoelectric single crystal material. The material of the piezoelectric sheet 101 includes but is not limited to the above-mentioned materials.

[0048] The mass block 103 in this embodiment is made of a metal block or a permanent magnet, wherein the N and S poles of the permanent magnet are connected facing each other and fixed at the ends of the long limb 202 and the short limb 203 by the magnetic force between them. The designed position of the mass block 103 can be flexibly changed, which can adjust the resonant frequency of the energy collector without changing the asymmetric bent beam structure 102; and, according to the needs of the service scenario, the magnetization direction of the magnet is reasonably adjusted to meet the energy collection needs of different service scenarios, which improves the flexibility of the energy collector and the adaptability to the service scenario.

[0049] The asymmetric bent beam structure 102 in this embodiment refers to a beam structure that has asymmetric bending or folding in its length direction. The asymmetric bent beam structure 102 is made of beryllium bronze or stainless steel, which is a material with a high elastic modulus. This design can change the stress distribution, deformation characteristics and vibration mode of the beam, so that the piezoelectric piece 101 is in a torsional mode under the excitation of the vibration source, which helps to improve the output power of the energy collector; the design of different asymmetric bent beam structures 102 can change the direction of the principal stress, thereby completing the diversification of the torsional mode of the piezoelectric piece 101; in addition, the asymmetric bent beam structure 102 design adopts a torsional vibration mode, which is smaller in length than the traditional cantilever beam structure, and also helps to miniaturize the device, ensuring that the energy collector unit works effectively and efficiently within the preset space range.

[0050] One end of the fixing screw 104 in this embodiment passes through the fixing hole, and fixes the asymmetric bent beam structure 102 by point clamping, and the other end of the fixing screw 104 is fixed on the rigid base. During the process of magneto-electric or force-electric conversion of the energy collector unit, the bent beam structures on the left and right sides of the fixing screw keep the fixing center almost still under opposite torques, which avoids energy loss caused by clamping loss to the greatest extent.

[0051] In this embodiment, when the energy collector causes the asymmetric bent beam structure 102 to undergo periodic torsional deformation due to an external vibration signal or magnetic field signal, the piezoelectric film 101 will be induced to undergo periodic deformation, and the piezoelectric film 101 will generate a periodic electrical signal on the surface based on the principle of the positive piezoelectric effect unique to piezoelectric materials; when the excitation frequency of the external vibration signal or magnetic field signal is consistent with the inherent resonant frequency of the energy collector, the vibration signal generated thereby is the largest, and energy collection will be more effective, thereby achieving higher energy conversion efficiency and output power.

[0052] In this embodiment, when the energy collector is in the service scenario of magneto-electric conversion, according to the different frequencies of the external alternating magnetic field, the reverse vibration mode of the long limb 202 and the reverse vibration mode of the short limb 203 can be stimulated, that is, the two long limbs 202 parts vibrate up and down and the two short limbs 203 parts vibrate up and down, which ensures that the phase difference between the alternating electrical signals of the piezoelectric sheet 101 is fixed to half a cycle. Whether it is the same-direction vibration mode in the force-electric conversion scenario or the reverse vibration mode in the magneto-electric conversion scenario, the series and parallel connection of the electrical signal will be easier to design the circuit due to the fixed phase difference.

[0053] In this embodiment, when the energy collector works in a multi-unit matrix form, it includes multiple energy collectors that work independently of each other, and multiple energy collectors that work independently of each other are arranged in a matrix form, each of which can collect energy according to different magneto-electric conversion and force-electric conversion service scenario requirements, further adapting to broadband energy collection needs. Through the matrix layout, multiple energy collector units can be efficiently integrated, significantly reducing the size of the energy collector in terms of space occupation, which is particularly suitable for scenarios with narrow layout space; and this matrix design allows functions to be modularly expanded according to scenario requirements, facilitating later maintenance and upgrades.

[0054] Specifically, the energy harvester serves the needs of magneto-electric conversion scenarios, and its structure is shown in the figure Figure 1 As shown; when the alternating magnetic field signal acts on the mass block 103 at the free end of the cantilever beam, since there is an angle between the direction of the alternating magnetic field and the magnetization direction of the permanent magnet of the mass block 103, the permanent magnet of the mass block 103 will be affected by the alternating magnetic force, which will cause the end of the asymmetric bent beam structure 102 to generate a magnetic torque, which will drive it to complete the tensile bending deformation process, and apply alternating torsional stress to the piezoelectric sheet 101 through the asymmetric bent beam structure 102, and generate an output electrical signal due to the positive piezoelectric effect; the collector will have two resonant modes in the resonant state, such as Figure 7 (Long limb reverse vibration mode) and Figure 8 (Short limb reverse vibration mode).

[0055] The fixing screw 104 fixes the energy collector to a rigid base through the fixing hole of the asymmetric bent beam structure 102 with bolts; during the magneto-electric conversion process of the energy collector, the cantilever beam structures on the left and right sides of the fixing screw 104 keep the fixing center almost stationary under opposite magnetic torques, which minimizes clamping losses.

[0056] The shape design of the piezoelectric sheet 101 has considerable flexibility and is not limited to common square or circular forms. Its internal structure also has diverse possibilities. It can be designed to include a perforated structure or a fully enclosed structure. By optimizing the shape design of the piezoelectric sheet, the energy collection efficiency can be improved to a certain extent.

[0057] The piezoelectric sheet 101 is arranged in multiple locations in the energy collector, and the polarization directions of the piezoelectric sheet 101 may be inconsistent, which can conveniently complete the electrical series connection and electrical parallel connection of the piezoelectric sheet 101. According to the requirements of different application scenarios, a larger output current can be obtained through electrical parallel connection, or a larger output voltage can be obtained through electrical series connection, which further improves the flexibility of use of the energy collector.

[0058] In summary, the magnetic-mechanical-electric coupling energy harvester based on the asymmetric torsional mode utilizes the torsional mode of the piezoelectric piece 101. During operation, the long-limb unidirectional vibration mode, the short-limb unidirectional vibration mode and the long-limb reverse vibration mode, the short-limb reverse vibration mode coexist, making the output signal larger. At the same time, based on the design concept of the asymmetric bent beam structure, this energy harvester has multiple service modes. Compared with the traditional cantilever beam type energy harvester, its output performance has a significant broadband advantage.

[0059] Moreover, during the magneto-electric conversion process of the energy collector unit, the cantilever beam structure on the left and right sides of the fixed screw keeps the fixed center almost stationary under opposite magnetic torques, which minimizes the "clamping loss". Compared with the traditional single-end clamped cantilever beam energy collector, the output power of the energy collector with this structure can be maximized.

[0060] Finally, no matter it is the same-direction vibration mode serving in the force-to-electric conversion scenario, or the opposite-direction vibration mode serving in the magneto-electric conversion scenario, the series and parallel connection of electrical signals will greatly reduce the difficulty of series and parallel operation due to the fixed phase difference; therefore, according to the requirements of different application scenarios, a larger output current can be obtained through electrical parallel connection, or a larger output voltage can be obtained through electrical series connection, which further improves the flexibility of use of the energy harvester and the reliability of series and parallel connection.

[0061] The use of high-performance piezoelectric single crystal materials can improve the output power density on this basis; independent energy collector units can also be assembled in arrays, further improving the flexibility of use of the energy collector and broadening the application scenarios of the energy collector.

[0062] In addition, it should be noted that the shapes and names of the parts and components of the specific embodiments described in this specification may be different, and the above content described in this specification is only an example of the structure of the present invention. All equivalent changes or simple changes made based on the structure, features and principles described in the patent concept of the present invention are included in the protection scope of the patent of the present invention. Technicians in the technical field of the present invention can make various modifications or supplements to the specific embodiments described or replace them in a similar manner, as long as they do not deviate from the structure of the present invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A magnetic-mechanical-electric coupling energy harvester based on an asymmetric torsional mode, characterized in that: The invention comprises a piezoelectric sheet (101) with polarization directions in the same or opposite directions to realize series or parallel connection of electrical signals, an asymmetric bent beam structure (102) that enables the piezoelectric sheet (101) to work in a torsion mode to realize energy output power, a mass block (103) for realizing energy collection, and a fixing screw (104) for mounting the asymmetric bent beam structure (102) on a rigid base; the polarization direction of the piezoelectric sheet (101) is arranged along the thickness direction, and electrode coatings are arranged on both sides of the piezoelectric sheet (101) along the thickness direction, and the electrode coatings on the two sides are defined as a bonding electrode surface and The asymmetric bent beam structure (102) comprises a main beam (201), a long limb (202) and a short limb (203) arranged in an integrated structure. A fixing hole is arranged in the middle of the main beam (201). The bonding electrode surface is bonded and fixed to the main beam (201) by epoxy resin and is distributed on the left and right sides of the fixing hole. The lead-out electrode surface leads out an electrical signal by a wire. The mass block (103) is fixed to the asymmetric bent beam structure (102) by magnetic force. One end of the fixing screw (104) is connected to the fixing hole. The fixing screw (104) is mounted on a rigid base.

2. The asymmetric torsional mode-based magnetic-mechanical-electric coupling energy harvester according to claim 1, characterized in that: The material of the piezoelectric sheet (101) is lead zirconate titanate (PZT) piezoelectric ceramic, bismuth scandate-lead titanate (BS-PT) piezoelectric ceramic, barium titanate (BaTiO3) piezoelectric ceramic, potassium sodium niobate (KNN) piezoelectric ceramic, lead magnesium niobate-lead titanate (PMN-PT) piezoelectric single crystal or lead zinc niobate-lead titanate (PZN-PT) piezoelectric single crystal material.

3. The magnetic-mechanical-electric coupling energy harvester based on asymmetric torsional mode according to claim 1, characterized in that: The mass block (103) is made of a metal block or a permanent magnet, wherein the N and S poles of the permanent magnet are connected facing each other and are fixed to the ends of the long limb (202) and the short limb (203) through the magnetic force between them.

4. The magnetic-mechanical-electric coupling energy harvester based on asymmetric torsional mode according to claim 1, characterized in that: The asymmetric bent beam structure (102) refers to a beam structure that is asymmetrically bent or folded in its length direction. The asymmetric bent beam structure (102) is made of beryllium bronze or stainless steel, a material with a relatively high elastic modulus.

5. The magnetic-mechanical-electric coupling energy harvester based on asymmetric torsional mode according to claim 1, characterized in that: One end of the fixing screw (104) passes through the fixing hole to fix the asymmetric bent beam structure (102) by point clamping, and the other end of the fixing screw (104) is fixed on a rigid base.

6. The magnetic-mechanical-electric coupling energy harvester based on asymmetric torsional mode according to claim 1, characterized in that: The main beam (201), the long limb (202), and the short limb (203) are arranged in a rectangular or trapezoidal structure.

7. The magnetic-mechanical-electric coupling energy harvester based on asymmetric torsional mode according to claim 1, characterized in that: The piezoelectric sheet (101) is arranged in a square or circular structure.

8. A working method based on the energy harvester according to claim 1, characterized in that: When the energy collector causes the asymmetric bent beam structure (102) to undergo periodic torsional deformation in response to an external vibration signal or magnetic field signal, the piezoelectric sheet (101) will be induced to undergo periodic deformation, and the piezoelectric sheet (101) will generate a periodic electrical signal on its surface based on the principle of the positive piezoelectric effect unique to piezoelectric materials; when the excitation frequency of the external vibration signal or magnetic field signal is consistent with the inherent resonant frequency of the energy collector, the vibration signal generated thereby is maximum.

9. The working method of the asymmetric torsional mode-based magnetic-mechanical-electric coupling energy harvester according to claim 8, characterized in that: When the energy collector is in a force-to-electric conversion service scenario, according to the different frequencies of external vibration signals, the long limbs (202) and the short limbs (203) can be stimulated to vibrate in the same direction, that is, the two long limbs (202) vibrate up and down at the same time, and the two short limbs (203) vibrate up and down at the same time, thereby ensuring that the phase difference between the alternating electrical signals of the piezoelectric sheet (101) is fixed to zero; when the energy collector is in a magneto-electric conversion service scenario, according to the different frequencies of external alternating magnetic fields, the long limbs (202) and the short limbs (203) can be stimulated to vibrate in the opposite direction, that is, the two long limbs (202) vibrate up and down, and the two short limbs (203) vibrate up and down, thereby ensuring that the phase difference between the alternating electrical signals of the piezoelectric sheet (101) is fixed to half a cycle.

10. The working method of the asymmetric torsional mode-based magnetic-mechanical-electric coupling energy harvester according to claim 8, characterized in that: When the energy collector works in a multi-unit matrix form, it includes multiple energy collectors working independently of each other. The multiple energy collectors working independently of each other are arranged in a matrix form, and each can collect energy according to different magneto-electric conversion and force-electric conversion service scenario requirements, further adapting to broadband energy collection needs.

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