A spatial magnetic field energy conversion device based on magnetoelectric materials

Abstract

A kind of space magnetic field energy conversion device based on magnetoelectric material, including annular magnetic fixed column with opening arrangement, simply supported beam is installed in annular magnetic fixed column, simply supported beam can be deformed to output voltage when magnetic field changes, annular magnetic fixed column is provided with the opening in simply supported beam width direction, annular magnetic fixed column can enhance the magnetic field intensity of the space where simply supported beam is located, the surface of simply supported beam is provided with magnetic mass, and magnetic mass can enhance the deformation of simply supported beam to improve output voltage.By using piezomagnetic piezoelectric material of simply supported beam structure, stress is dispersed at the both ends of simply supported beam, stress distribution is more uniform, and the strain distribution of entire simply supported beam is more uniform, energy conversion efficiency is better, simply supported beam is installed in hollow annular magnetic fixed column, the magnetic function of annular magnetic fixed column is used, dispersed magnetic field is converged in annular region, the magnetic field intensity around simply supported beam is improved, and magnetic field distribution is more uniform.

Description

Technical Field

[0001] This application relates to the field of energy harvesting technology, and in particular to a novel space magnetic field energy conversion device designed based on a groove-enhanced magnetoelectric material that utilizes changes in a weak magnetic field in space. Background Technology

[0002] The rapid development of IoT and wireless sensor technologies has led to an increasing demand for miniaturized and long-life power supplies. Traditional battery-powered systems suffer from limited lifespan and the need for replacement or recharging. The ubiquitous magnetic fields in space, such as the power frequency magnetic fields generated by electrical equipment and communication base stations, provide a potential source of energy harvesting. In particular, the direct conversion of magnetic energy into electrical energy using magnetoelectric materials offers a new approach to achieving efficient and self-powered sensor networks.

[0003] Most existing magnetoelectric transducers employ a cantilever beam structure composed of piezoelectric and piezomagnetic materials. Their working principle is that the magnetic field first drives the piezoelectric material to produce strain, which in turn drives the piezoelectric crystal to produce strain, thereby outputting voltage.

[0004] However, in piezoelectric materials of cantilever beam structures, stress is concentrated at the fixed end of the cantilever beam structure, which makes them prone to cracking due to material fatigue. Furthermore, the conversion efficiency and total output energy of space magnetic field energy conversion are still relatively low. Magnetic field energy is not effectively converted into electric field energy. In particular, under weak magnetic field conditions, the deformation caused by magnetostriction is low. After mechanical coupling, the deformation of piezoelectric materials is also low, affecting both output efficiency and total output energy. Summary of the Invention

[0005] In view of the above-mentioned prior art, this application provides a space magnetic field energy conversion device based on magnetoelectric materials. By using a piezoelectric material with a simply supported beam structure, the stress is dispersed at both ends of the simply supported beam, the stress distribution is more uniform, and the strain distribution of the entire simply supported beam is more uniform, resulting in better energy conversion efficiency. The simply supported beam is installed in a hollow annular magnetic focusing column. By utilizing the magnetic focusing function of the annular magnetic focusing column, the dispersed magnetic field is concentrated in the annular area, thereby increasing the magnetic field strength around the simply supported beam and making the magnetic field distribution more uniform.

[0006] To achieve the above objectives, the technical solution of this invention is implemented as follows: A space magnetic field energy conversion device based on magnetoelectric materials includes an annular magnetic fixing column with an opening. A simply supported beam is installed inside the annular magnetic fixing column. The simply supported beam includes a piezoelectric material layer. A magnetostrictive material layer is connected to the lower surface of the piezoelectric material layer. The piezoelectric material layer deforms to output voltage when the magnetic field changes. Grooves are formed on both the upper and lower surfaces of the piezoelectric material layer. The grooves are evenly distributed along the length of the piezoelectric material layer and the groove direction is along the width direction of the piezoelectric material layer. The annular magnetic fixing column is made of permalloy to enhance the magnetic field strength of the space where the simply supported beam is located. A magnetic mass block is fixedly connected to the lower surface of the magnetostrictive material layer. The change of magnetic field inside the annular magnetic fixing column drives the magnetic mass block to move and cooperate with the deformation of the magnetostrictive material layer to enhance the deformation and bending degree of the simply supported beam.

[0007] Furthermore, a hinge support is provided on one side wall of the annular magnetic fixing column, and a slot is provided on the hinge support. A sliding support is provided on the opposite side wall of the annular magnetic fixing column, and a through slot is provided on the sliding support. A first rotating shaft is provided at one end of the simply supported beam along its length. The end of the first rotating shaft passes through the slot and is rotatably connected to the hinge support. A second rotating shaft is provided at the other end of the simply supported beam along its length. The end of the second rotating shaft passes through the through slot and moves horizontally within the through slot.

[0008] Furthermore, the magnetic mass block is located in the middle of the lower surface of the magnetostrictive material layer.

[0009] Furthermore, the magnetostrictive material layer and the piezoelectric material layer are bonded together with epoxy resin.

[0010] Furthermore, the number of grooves on both the upper and lower surfaces of the piezoelectric material layer is at least six.

[0011] Furthermore, the grooves on the upper and lower surfaces of the piezoelectric material layer are arranged symmetrically.

[0012] Furthermore, the inner corner of the groove near the center of the piezoelectric material layer in the thickness direction is designed with a chamfer.

[0013] Furthermore, the depth of the trench is one-sixth to one-quarter of the thickness of the piezoelectric material layer, and the total width of the trenches on one side of the piezoelectric material layer is less than one-half of the length of the piezoelectric material layer.

[0014] Furthermore, multiple sets of simply supported beams are installed in the height direction inside the annular magnetic fixing column, and the output ends of the multiple sets of simply supported beams are connected in series or in parallel.

[0015] The beneficial effects of this invention are as follows: The simply supported beam is installed inside the hollow annular magnetic fixing column. The change in the magnetic field causes the simply supported beam to deform and bend to output voltage. Through the magnetic focusing effect of the annular magnetic fixing column, the dispersed magnetic field is concentrated in the annular area, increasing the magnetic field strength around the simply supported beam, resulting in greater deformation of the simply supported beam and increasing the output voltage. At the same time, the piezoelectric material of the simply supported beam structure is supported at both ends, so the stress will not be concentrated at one end of the simply supported beam. During long-term operation, the stress concentration is small, and the durability and reliability of the entire energy conversion device are higher.

[0016] One end of the simply supported beam is hinged to the inner wall of the annular magnetic fixing column, allowing it to rotate vertically. The other end of the simply supported beam is movablely hinged to the inner wall of the annular magnetic fixing column. This means that when the simply supported beam bends, it can rotate vertically and move horizontally a certain distance along the through groove. In other words, the axial distance of the simply supported beam can be slightly adjusted, reducing its axial stiffness. This results in a larger vibration amplitude, less energy loss, and a larger output voltage.

[0017] Grooves are created on the upper and lower surfaces of the piezoelectric material layer, resulting in greater deformation due to stress. The grooves make the piezoelectric material layer more prone to deformation, and the deformation of each groove structure is greater than that without grooves, thus increasing the overall deformation of the piezoelectric material layer. Since the amount of electrical energy generated by the piezoelectric material is directly related to the deformation, this structure enables the piezoelectric material layer to generate more electrical energy.

[0018] The grooves on the upper and lower surfaces of the piezoelectric material layer are symmetrically distributed, resulting in better strain matching. The symmetrical grooves allow the strain concentration areas on the upper and lower surfaces to correspond to the strain peak areas of the simply supported beam.

[0019] The inner corner of the groove near the center of the piezoelectric material layer in the thickness direction is chamfered. When the piezoelectric material is bent, the corner of the groove is a typical stress concentration area. The chamfer design avoids material fatigue or fracture caused by stress concentration and extends the service life of the energy conversion device.

[0020] Multiple sets of simply supported beams are installed inside the annular magnetic fixed column, and the output ends of the multiple sets of simply supported beams are connected in series and parallel to increase the total output energy.

[0021] Permalloy magnetic material is used to construct a closed-loop fixing column, which, while fixing a simply supported beam, forms a magnetic ring structure, increasing the total magnetic flux obtained and enabling the acquisition of omnidirectional magnetic fields. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of an overall space magnetic field energy conversion device based on magnetoelectric materials according to the present invention; Figure 2This is a front view of a space magnetic field energy conversion device based on magnetoelectric materials according to the present invention. Figure 3 This is an enlarged view of region A of a space magnetic field energy conversion device based on magnetoelectric materials according to the present invention; Figure 4 This is a schematic diagram of a simply supported beam structure of a space magnetic field energy conversion device based on magnetoelectric materials according to the present invention.

[0023] The reference numerals in the attached figures are as follows: 1. Annular magnetic fixing column; 2. Simply supported beam; 3. Magnetic mass block; 4. Hinge support; 5. Sliding support; 6. Magnetostrictive material layer; 7. Piezoelectric material layer; 8. Groove; 9. Through slot; 10. First rotating shaft; 11. Hole slot; 12. Second rotating shaft. Detailed Implementation

[0024] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. In the following description, the expression "some embodiments" refers to a subset of all possible embodiments; however, it should be understood that "some embodiments" can be the same subset or different subsets of all possible embodiments and can be combined with each other without conflict.

[0025] Combined with reference to the appendix Figures 1 to 4 This invention provides a space magnetic field energy conversion device based on magnetoelectric materials, comprising an annular magnetic fixing column 1 with an opening, a simply supported beam 2 installed inside the annular magnetic fixing column 1, the simply supported beam 2 including a piezoelectric material layer 7, a magnetostrictive material layer 6 connected to the lower surface of the piezoelectric material layer 7, the piezoelectric material layer 7 deforms to output voltage when the magnetic field changes, grooves 8 are formed on both the upper and lower surfaces of the piezoelectric material layer 7, the grooves 8 are uniformly distributed along the length direction of the piezoelectric material layer 7, and the groove direction of the grooves 8 is formed along the width direction of the piezoelectric material layer 7, the annular magnetic fixing column 1 is made of permalloy to enhance the magnetic field strength of the space where the simply supported beam 2 is located, a magnetic mass block 3 is fixedly connected to the lower surface of the magnetostrictive material layer 6, the magnetic field change inside the annular magnetic fixing column 1 drives the magnetic mass block 3 to move and cooperate with the deformation of the magnetostrictive material layer 6 to enhance the deformation and bending degree of the simply supported beam 2.

[0026] The simply supported beam 2 is installed inside the annular magnetic fixing column 1. Both ends of the simply supported beam 2 can rotate. When the magnetic field changes, the simply supported beam 2 bends and is distributed in a symmetrical parabolic shape along the length of the simply supported beam 2. The strain is the largest in the middle area and gradually decreases towards both ends. This symmetrical distribution allows the simply supported beam 2 to bear the strain more evenly. The material participation of the entire structure of the simply supported beam 2 is higher, which effectively avoids the problem of local high strength and overall low efficiency of cantilever beam structures.

[0027] Meanwhile, the simply supported beam 2 is installed inside the annular magnetic fixing column 1. Through the dual functions of magnetic enhancement and structural constraint to stabilize vibration, the synergistic effect of piezomagnetism-piezoelectricity is strengthened, and the sensitivity of the energy conversion device is improved. By utilizing the magnetic focusing function of the annular magnetic fixing column 1, the magnetic field dispersed in space is gathered into the annular magnetic fixing column 1, which significantly improves the magnetic field strength around the simply supported beam 2 and makes the magnetic field distribution more uniform. The originally weak magnetic field changes can produce more obvious deformation of the simply supported beam 2 after being amplified by the magnetic focusing of the annular magnetic fixing column 1, thereby improving the efficiency and sensitivity of magnetoelectric conversion.

[0028] Furthermore, the annular magnetic fixing column 1 made of permalloy can construct a magnetic circuit, reduce magnetic field leakage, improve the utilization rate of the magnetic field, and avoid energy waste.

[0029] The annular magnetic fixing column 1 is a closed-loop structure. The closed-loop structure can be square, circular, or other shapes. The internal length of the annular magnetic fixing column 1 is determined by the length of the simply supported beam 2. The fixing column is formed by die-casting multiple square permalloy pieces.

[0030] A weak magnetic field is distributed in space. Permalloy has high magnetic permeability. After forming a closed-loop structure, it can concentrate the surrounding magnetic field and increase the magnetic flux per unit volume. At the same time, compared with the case without a magnetic field concentration structure, the annular magnetic field concentration fixing column 1 can also collect magnetic fields in multiple spatial directions, so that the energy harvesting simply supported beam 2 does not need to consider the direction of the spatial magnetic field.

[0031] The permalloy magnetic plates set at both ends of the simply supported beam 2 along its length constrain more magnetic fields to pass through the magnetostrictive material layer 6 along the length of the simply supported beam 2, and are consistent with the deformation direction of the magnetostrictive material layer 6, thus reducing losses.

[0032] The permalloy magnetic plates installed at both ends of the simply supported beam 2 in the vibration direction, i.e., the up and down direction, reduce the leakage of the magnetic field into the vibration space, maintain the magnetic field strength in dynamic vibration, help form a closed magnetic circuit, and improve the overall magnetic efficiency.

[0033] The groove 8 can reduce the local strength of the piezoelectric material layer 7, so that the stress of the piezoelectric material layer 7 when bending is evenly distributed throughout the entire piezoelectric material layer 7, rather than concentrated in a certain area. The groove 8 increases the deformation of the piezoelectric material layer 7 under the same deformation of the magnetostrictive material layer 6.

[0034] The stress generated by the deformation of the magnetostrictive material layer 6 due to the same weak magnetic field change is the same. When the piezoelectric material layer 7 does not have grooves 8, the stress of the magnetostrictive material layer 6 results in a smaller deformation of the piezoelectric material layer 7 because the stress needs to bend the entire piezoelectric material layer 7. However, when it has grooves 8, the grooves 8 make it easier for the piezoelectric material layer 7 to deform. The deformation of the piezoelectric material layer 7 with grooves 8 is greater than that without grooves 8, resulting in a larger overall deformation of the piezoelectric material layer 7. Since the amount of electrical energy generated by the piezoelectric material layer 7 is directly related to the deformation, this structure can enable the piezoelectric material layer 7 to output more electrical energy.

[0035] The trench 8 described above uses optical masking and photolithography to control the width of the trench 8. Protective adhesive is applied to the areas where the trench 8 does not need to be etched. The protective adhesive on the top of the trench 8 is removed by photolithography. Then, the required shape of the trench 8 is etched by a wet process. Hydrochloric acid is used as the etchant, and the depth of the trench 8 is controlled by the etching time. A magnetic mass block 3 is installed on the surface of the simply supported beam 2. The magnetic mass block 3 is a permanent magnet, which can be a ferrite magnet or a neodymium iron boron magnet. The magnetic mass block 3 generates additional magnetoelastic force through magnetic interaction with the magnetic field in the annular magnetic fixing column 1, which further enhances the vibration of the simply supported beam 2.

[0036] The combination of the simply supported beam 2, the annular magnetic fixing column 1, and the magnetic mass block 3 can simultaneously enhance the dual-path energy conversion of "magnetostriction → mechanical strain → piezoelectric effect". When the magnetic field changes periodically, the length of the simply supported beam 2 changes, which is transformed into the vibration of the simply supported beam 2, and then outputs voltage. The magnetic mass block on the simply supported beam 2 vibrates accordingly. The relative motion between the magnetic mass block 3 and the annular magnetic fixing column 1 causes the magnetic flux passing through the simply supported beam 2 to change drastically, further increasing the deformation of the simply supported beam 2, and thus increasing the output voltage of the simply supported beam 2.

[0037] Preferably, a hinge support 4 is provided on one side wall of the annular magnetic fixing column 1, and a slot 11 is provided on the hinge support 4. A sliding support 5 is provided on the opposite side wall of the annular magnetic fixing column 1, and a through slot 9 is provided on the sliding support 5. A first rotating shaft 10 is provided at one end of the simply supported beam 2 along its length. The end of the first rotating shaft 10 passes through the slot 11 and is rotatably connected to the hinge support 4. A second rotating shaft 12 is provided at the other end of the simply supported beam 2 along its length. The end of the second rotating shaft 12 passes through the through slot 9 and moves horizontally within the through slot 9.

[0038] Two hinge supports 4 are provided on one side wall of the annular magnetic fixing column 1. The hinge supports 4 have slots 11. A first rotating shaft 10 is provided at one end of the simply supported beam 2 along its length. Each end of the first rotating shaft 10 passes through a slot 11. The ends of the first rotating shaft 10 are rotatably connected to the hinge supports 4. When the simply supported beam 2 deforms and bends, the first rotating shaft 10 can rotate in the vertical direction. Two sliding supports 5 are provided on opposite side walls of the annular magnetic fixing column 1. The sliding supports 5 have through slots 9. A second rotating shaft 12 is provided at the other end of the simply supported beam 2 along its length. Each end of the second rotating shaft 12 passes through a through slot 9. The ends of the second rotating shaft 12 can move horizontally within the through slots 9, that is, move a certain small distance along the axis of the simply supported beam 2. When the simply supported beam 2 vibrates, the second rotating shaft 12 can also rotate in the vertical direction.

[0039] One solution is to slide the second rotating shaft 12 to the sliding support 5, thereby reducing the energy loss caused by friction between the second rotating shaft 12 and the sliding support 5 by reducing the friction between them.

[0040] Another option is to install a roller at the end of the second rotating shaft 12. The roller rolls in the through groove 9, which serves as the roller's track and limits its movement. This further reduces frictional loss between the second rotating shaft 12 and the sliding support 5, reduces vibration energy loss, and fully converts magnetic field energy into electrical energy.

[0041] Meanwhile, when the magnetic field changes periodically, causing the simply supported beam 2 to vibrate and output voltage, one end of the simply supported beam 2 is hinged through the first rotating shaft 10 and can only rotate, while the other end of the simply supported beam 2 is freely rotated through the second rotating shaft 12 and can make slight horizontal movements, which is the axial expansion and contraction of the simply supported beam 2. The vibration bending energy of the simply supported beam 2 is more free and there is no axial constraint. When the simply supported beam 2 bends, the strain is distributed parabolically along the length direction of the simply supported beam 2. The strain is the largest in the middle area, which is the area away from the two ends. Moreover, the expansion and contraction strain of the upper and lower surfaces is purely generated by bending without additional axial stress interference. This pure bending strain can be efficiently converted into voltage by the piezoelectric material layer 7. The piezoelectric effect responds most directly to bending strain.

[0042] Furthermore, the second rotating shaft 12 can make slight horizontal movements within the through groove 9, meaning that the axial stiffness of the simply supported beam 2 is low, and under the same vibration conditions, the strain in the middle region can reach its maximum value.

[0043] If both ends of the simply supported beam 2 are hinged and cannot move slightly along its axis, when the simply supported beam 2 bends downward, the axial stress on the first shaft 10 and the second shaft 12 will offset the deformation of the simply supported beam 2. That is, when the simply supported beam 2 bends, the lower side of the simply supported beam 2 should be stretched and lengthened. The axial compressive stress on the first shaft 10 and the second shaft 12 restricts the stretching of the lower side of the simply supported beam 2 because the upper side of the simply supported beam 2 is compressed and shortened. When the first shaft 10 and the second shaft 12 cannot move axially, it is equivalent to applying additional tensile stress to the upper side of the simply supported beam 2, which prevents the upper side of the simply supported beam 2 from shortening. Ultimately, the effective bending strain of the upper and lower surfaces is partially offset, reducing the degree of deformation of the simply supported beam 2. In other words, the output voltage of the simply supported beam 2 is limited and can only output a certain voltage. The offsetting effect is more obvious, especially during large amplitude vibrations.

[0044] Preferably, the magnetic mass block 3 is located in the middle of the lower surface of the magnetostrictive material layer 6.

[0045] The vibration characteristics of the simply supported beam 2 determine that its middle region is the location with the largest displacement and bending moment. When the magnetic field changes and causes the simply supported beam 2 to bend and deform, the strain in the middle region of the simply supported beam 2 is the largest. The output voltage of the simply supported beam 2 depends on the conversion of the strain energy of the simply supported beam 2. When the magnetic mass block 3 is installed in the middle of the lower surface of the magnetostrictive material layer 6, the inertial force of the magnetic mass block 3 will directly act on the maximum deformation area of ​​the simply supported beam 2, forcing the simply supported beam 2 to generate a larger bending strain at this position, thereby maximizing the conversion of mechanical vibration energy into electrical signals of the piezoelectric material layer 7, and significantly improving the energy conversion efficiency of the simply supported beam 2.

[0046] The magnetic mass block 3 is located at the geometric symmetry center of the simply supported beam 2 structure. The force and deformation of the simply supported beam 2 will be symmetrically distributed, which can avoid the off-center load effect caused by the offset of the mass block, improve the stability of energy conversion, and also avoid the accelerated material fatigue caused by long-term off-center load. When the magnetic mass block 3 is located in the middle of the simply supported beam 2, it can extend the service life of the simply supported beam 2.

[0047] When the magnetic mass block 3 is located in the middle of the simply supported beam 2, it can make the strain uniformly borne by all parts of the simply supported beam 2, make full use of its active area, and reduce energy loss.

[0048] When the magnetic mass block 3 is located in the middle of the simply supported beam 2, the mass inertia of the magnetic mass block 3 and the elastic deformation energy of the simply supported beam 2 can form a more efficient resonant coupling, making it easier for the magnetic mass block 3 and the simply supported beam 2 to reach a resonant state when the magnetic field changes.

[0049] Preferably, the magnetostrictive material layer 6 and the piezoelectric material layer 7 are bonded together with epoxy resin.

[0050] There is no epoxy resin in groove 8 The magnetostrictive material layer 6 and the piezoelectric material layer 7 are bonded together with epoxy resin to form a whole. At the same time, the epoxy resin serves as a stress buffer layer between the magnetostrictive material layer 6 and the piezoelectric material layer 7.

[0051] When the magnetic field changes and the magnetostrictive material layer 6 is stretched, the huge strain acts directly on the brittle piezoelectric material layer 7, generating shear stress at the connection between the magnetostrictive material layer 6 and the piezoelectric material layer 7. This stress can easily damage the piezoelectric material layer 7 and affect its performance. By using a flexible epoxy resin buffer, the piezoelectric material layer 7 can withstand more uniform stretching strain.

[0052] At the same time, epoxy resin is an insulator, which can effectively avoid the risk of short circuits between electrodes.

[0053] Preferably, the number of grooves 8 on both the upper and lower surfaces of the piezoelectric material layer 7 is at least six.

[0054] The number of grooves 8 on the upper and lower surfaces of the piezoelectric material layer 7 is at least six. When the number of grooves 8 is less than six, the number of grooves 8 is too small, so that the grooves 8 have an insignificant effect on improving the deformation of the piezoelectric material layer 7, which means that the improvement of the power generation effect of the entire piezoelectric material layer 7 is not significant.

[0055] The appropriate number of grooves 8 are set according to the length of the piezoelectric material layer 7 to avoid the overall stiffness of the piezoelectric material layer 7 being reduced due to the grooves 8 being too dense.

[0056] Preferably, the grooves 8 on the upper and lower surfaces of the piezoelectric material layer 7 are arranged symmetrically.

[0057] When the simply supported beam 2 bends, that is, when the upper surface of the piezoelectric material layer 7 is compressed, the lower surface is stretched. The strain amplitude along the length of the piezoelectric material layer 7 is symmetrical about the midpoint. The upper and lower grooves 8 are on the same vertical line, which can guide the strain of the upper and lower surfaces to be released or enhanced uniformly at the corresponding positions. This makes the peak positions of the tensile strain and compressive strain on the piezoelectric material layer 7 symmetrical and fixed, which can maximize the utilization of the active area of ​​the piezoelectric material layer 7 and improve the mechanical energy to electrical energy conversion efficiency of the entire energy conversion device.

[0058] The groove 8 optimizes stress distribution by changing the local morphology of the piezoelectric material layer 7. If the grooves 8 on the upper and lower surfaces of the piezoelectric material layer 7 are misaligned, that is, the grooves 8 on the upper and lower surfaces of the piezoelectric material layer 7 are not on the same vertical line, when the piezoelectric material layer 7 is bent, the stress at the groove 8 on the upper surface of the piezoelectric material layer 7 and the stress at the groove 8 on the lower surface of the piezoelectric material layer 7 are not coordinated with each other. Local stress superposition may form at the junction of the misaligned grooves 8 on the upper and lower surfaces of the piezoelectric material layer 7. Under long-term vibration, the piezoelectric material layer 7 is prone to cracking.

[0059] The grooves 8 on the upper and lower surfaces of the piezoelectric material layer 7 are arranged symmetrically, meaning that the effective power generation area between adjacent grooves 8 is also symmetrical, making the charge output of the entire piezoelectric material layer 7 more stable and the superposition efficiency higher.

[0060] Preferably, the inner corner of the groove 8 near the center of the piezoelectric material layer 7 in the thickness direction is designed with a chamfer.

[0061] The corner of the groove 8 is a typical stress concentration area. The stress concentration coefficient at the corner of the groove 8 is large. When the piezoelectric material layer 7 is repeatedly bent and deformed, tiny cracks may be generated at the corner of the groove 8. The cracks will gradually expand as the piezoelectric material layer 7 is repeatedly deformed, eventually leading to fracture at the groove, until the piezoelectric material layer 7 loses its power generation function.

[0062] The corners of the groove 8 are designed as chamfers, which can be rounded or beveled. Rounded corners are a better option. By smoothly transitioning the geometry, the stress at the corners of the groove 8 is dispersed, the local stress peak is reduced, and the piezoelectric material layer 7 is prevented from breaking at the corners of the groove 8.

[0063] Thus, the chamfered groove 8 can both weaken the stiffness and concentrated strain of the entire piezoelectric material layer 7 and ensure the long-term stable operation of the piezoelectric material layer 7.

[0064] When using a rounded corner design at the bend of the groove 8, the radius of the rounded corner is 20%-30% of the width of the groove 8. When the radius of the rounded corner is less than 20% of the width of the groove 8, the chamfer of the bend of the groove 8 is too small and cannot effectively disperse the stress. When the radius of the rounded corner is greater than 30% of the width of the groove 8, the effective width of the groove 8 is reduced, which weakens the effect of the groove 8 on the stiffness of the piezoelectric material layer 7.

[0065] Preferably, the depth of the trench 8 is one-sixth to one-quarter of the thickness of the piezoelectric material layer 7, and the total width of the trench 8 on one side of the piezoelectric material layer 7 is less than one-half of the length of the piezoelectric material layer 7.

[0066] When the ratio of the depth of the trench 8 to the thickness of the piezoelectric material layer 7 is less than one-sixth, the depth of the trench 8 is too shallow, the optimization effect of the trench 8 is not obvious, resulting in an insignificant reduction in the stiffness of the entire piezoelectric material layer 7, and a limited improvement in the energy conversion efficiency of the entire energy conversion device.

[0067] When the ratio of the depth of the groove 8 to the thickness of the piezoelectric material layer 7 is greater than one-quarter, because the upper and lower grooves 8 are symmetrically arranged, the effective thickness of the piezoelectric material layer 7 at the groove 8 is the original thickness of the piezoelectric material layer 7 minus twice the groove depth of the groove 8. If the thickness at the connection of the piezoelectric material layer 7 is too small, the structural stiffness of the piezoelectric material layer 7 will decrease sharply due to the groove 8. When the piezoelectric material layer 7 undergoes bending vibration, the piezoelectric material layer 7 is prone to cracking at the bottom of the groove 8, which will cause the entire piezoelectric material layer 7 to lose its power generation function.

[0068] When the total width of the grooves 8 on one side of the piezoelectric material layer 7 is greater than half the length of the piezoelectric material layer 7, the groove width of the grooves 8 is too large, and the effective material area of ​​the piezoelectric material layer between adjacent grooves 8 will be very small. Reducing the effective material area of ​​the piezoelectric material layer 7 will lead to a decrease in power generation efficiency.

[0069] Preferably, multiple sets of simply supported beams 2 are installed in the height direction inside the annular magnetic fixing column 1, and the output ends of the multiple sets of simply supported beams 2 are connected in series or in parallel.

[0070] By connecting multiple simply supported beams 2 in series or parallel, the energy output can be increased to improve the final output current, voltage and power, thereby better matching with the subsequent energy management circuit and significantly increasing the total output energy.

[0071] The simply supported beams 2 that are adjacent to each other are spaced a certain distance apart, so that they will not collide or interfere with each other and thus cause energy loss when the simply supported beams 2 are bent and deformed.

[0072] Working principle: A piezoelectric material layer 7 and a magnetostrictive material layer 6 are bonded together with epoxy resin to form a simply supported beam 2. A first rotating shaft 10 is provided at one end of the simply supported beam 2. A hinge support 4 is provided on one side wall inside the annular magnetic fixing column 1. A slot 11 is provided on the hinge support 4. The end of the first rotating shaft 10 passes through the slot 11 and is rotatably connected to the hinge support 4. A second rotating shaft 12 is provided at the other end of the simply supported beam 2. A sliding support 5 is provided on the opposite side wall inside the annular magnetic fixing column 1. A through slot 9 is provided on the sliding support 5. The end of the second rotating shaft 12 passes through the through slot 9. A magnetic mass block 3 is installed on the magnetic... Grooves 8 are formed on the lower surface of the magnetostrictive material layer 6 and on the upper and lower surfaces of the piezoelectric material layer 7. When the magnetic field in space changes periodically, when the magnetic field becomes stronger, the magnetostrictive material layer 6 stretches and becomes longer, while the length of the piezoelectric material layer 7 remains unchanged, causing the middle of the entire simply supported beam 2 to bend downwards. The grooves 8 make the bending more uniform. When the magnetic field becomes weaker, the magnetostrictive material layer 6 shortens and compresses the piezoelectric material layer 7, reducing the bending deformation of the entire simply supported beam 2 to return to a horizontal state. During the periodic changes in the magnetic field, the piezoelectric material layer 7 continuously bends and vibrates, thereby generating periodic voltage output from the electrodes.

[0073] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. The scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A space magnetic field energy conversion device based on magnetoelectric materials, characterized in that: The device includes an annular magnetic fixing column (1) with an opening, a simply supported beam (2) installed inside the annular magnetic fixing column (1), the simply supported beam (2) including a piezoelectric material layer (7), a magnetostrictive material layer (6) connected to the lower surface of the piezoelectric material layer (7), the piezoelectric material layer (7) deforms to output voltage when the magnetic field changes, grooves (8) are opened on both the upper and lower surfaces of the piezoelectric material layer (7), the grooves (8) are evenly distributed along the length direction of the piezoelectric material layer (7), and the groove direction of the grooves (8) is opened along the width direction of the piezoelectric material layer (7). The annular magnetic fixing column (1) is made of permalloy to enhance the magnetic field strength of the space where the simply supported beam (2) is located. A magnetic mass block (3) is fixedly connected to the lower surface of the magnetostrictive material layer (6). The change of the magnetic field inside the annular magnetic fixing column (1) drives the magnetic mass block (3) to move and cooperate with the deformation of the magnetostrictive material layer (6) to enhance the deformation and bending degree of the simply supported beam (2). A hinge support (4) is provided on one side wall of the annular magnetic fixing column (1), and a slot (11) is provided on the hinge support (4). A sliding support (5) is provided on the opposite side wall of the annular magnetic fixing column (1), and a through slot (9) is provided on the sliding support (5). A first rotating shaft (10) is provided at one end of the simply supported beam (2) along its length. The end of the first rotating shaft (10) passes through the slot (11) and is rotatably connected to the hinge support (4). A second rotating shaft (12) is provided at the other end of the simply supported beam (2) along its length. The end of the second rotating shaft (12) passes through the through slot (9) and moves horizontally within the through slot (9).

2. The space magnetic field energy conversion device based on magnetoelectric materials according to claim 1, characterized in that: The magnetic mass block (3) is located in the middle of the lower surface of the magnetostrictive material layer (6).

3. The space magnetic field energy conversion device based on magnetoelectric materials according to claim 1, characterized in that: The magnetostrictive material layer (6) and the piezoelectric material layer (7) are bonded together with epoxy resin.

4. The space magnetic field energy conversion device based on magnetoelectric materials according to claim 1, characterized in that: The number of grooves (8) on the upper and lower surfaces of the piezoelectric material layer (7) is at least six.

5. A space magnetic field energy conversion device based on magnetoelectric materials according to claim 4, characterized in that: The grooves (8) on the upper and lower surfaces of the piezoelectric material layer (7) are arranged symmetrically.

6. The space magnetic field energy conversion device based on magnetoelectric materials according to claim 3, characterized in that: The inner corner of the groove (8) near the center of the piezoelectric material layer (7) in the thickness direction is designed with a chamfer.

7. A space magnetic field energy conversion device based on magnetoelectric materials according to claim 3, characterized in that: The depth of the groove (8) is one-sixth to one-quarter of the thickness of the piezoelectric material layer (7), and the total width of the groove (8) on one side of the piezoelectric material layer (7) is less than one-half of the length of the piezoelectric material layer (7).

8. A space magnetic field energy conversion device based on magnetoelectric materials according to claim 1, characterized in that: Multiple sets of simply supported beams (2) are installed in the height direction inside the annular magnetic fixing column (1), and the output ends of the multiple sets of simply supported beams (2) are connected in series or in parallel.

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