Arched magnetostrictive composite array for collecting human motion energy

Abstract

The invention relates to an arched magnetostrictive composite array for collecting human motion energy. The composite array is composed of n energy collection units, wherein n is equal to 2-100000; each energy collection unit comprises an arched magnetostrictive composite structure, a pickup coil and a bias magnet; the two ends of the arched magnetostriction composite structure are each wound with a pickup coil. A bias magnet is fixed right above each pickup coil; the arched magnetostriction composite structure comprises a magnetostriction layer and a fixed layer; wherein the magnetostriction layer is embedded in the fixed layer; the magnetostriction layer is an arched magnetostriction wire and is made of iron-gallium alloy. The device has the advantages of simple structure, easy carrying, large output signal, wide application and the like, and is extremely suitable for the field of human motion energy collection.

Description

Technical Field:

[0001] The present invention relates to the field of motion energy harvesting, and more specifically, to an arched magnetostrictive energy harvesting array that can achieve human motion energy harvesting. Background Art:

[0002] In the current era of rapid technological development, electronic devices are moving forward rapidly towards intelligence and integration. With the increasing richness of functions, the number of electronic components required in a unit space is continuously rising, which directly leads to a continuous increase in energy consumption. Therefore, the power supply problem has become a major problem that needs to be solved urgently in the design of electronic devices, attracting the attention of many researchers. To solve this problem, people have started to actively explore available energy from the surrounding environment, such as light energy, thermal energy, and acoustic vibration energy. In recent years, motion energy harvesting technology has attracted much attention. It can convert the mechanical energy generated by various vibrations of the human body into electrical energy to continuously power wearable devices, and is expected to solve a series of problems existing in traditional battery power supply, such as large mass and volume, short lifespan, and environmental pollution. Currently, motion energy harvesting technology mainly includes three types: triboelectric, piezoelectric, and magnetostrictive.

[0003] Triboelectric energy harvesting is based on the principles of triboelectrification and electrostatic induction to convert mechanical energy into electrical energy. Although the output signal is large, it is easily worn, and the voltage will drop after long-term use; piezoelectric materials are brittle and prone to damage during long-term operation, and charge leakage may also occur. Moreover, due to its capacitive characteristics, piezoelectric has a very high output impedance. In contrast, magnetostrictive materials stand out due to their unique force-magnetic coupling effect. It can convert the applied stress / strain into magnetic changes, and then achieve electrical energy harvesting in a coil, ultimately achieving the goal of fast and efficient energy harvesting. Compared with triboelectric, piezoelectric and other energy harvesting technologies, magnetostrictive shows obvious advantages in many key aspects such as applicable frequency band, conversion efficiency, and energy density, and has broad application prospects.

[0004] Currently, magnetostrictive vibration energy harvesting technology still faces many challenges such as low material pressure resistance and low output signal. For example: Patent No. CN 118432394 A, a human motion energy capture device based on Fe-Co alloy. This patent uses Fe-Co alloy wire as the core component and designs a composite flat structure with the core component being a magnetostrictive material, which has good force recovery and realizes the harvesting of human motion energy. However, the output signal of Fe-Co alloy is poor, and at the same time, the deformation amount of the flat structure under force is small, and the magnetic domains in the magnetostrictive layer cannot be fully utilized. Therefore, magnetostrictive energy harvesting technology still needs further improvement. Summary of the Invention:

[0005] The object of the present invention is to address the deficiencies in the current technology. The present invention proposes an arched magnetostrictive composite array for harvesting human motion energy. The collector has a novel arched + array structure. On the basis of enhancing the stress deformation of the magnetostrictive alloy, the output voltage is further superimposed. This innovative design fully improves the collection efficiency of the energy harvester. The present invention has the advantages of simple structure, easy to carry, large output signal, wide application, etc., and is extremely suitable for the field of human motion energy harvesting.

[0006] The technical solution adopted by the present invention to solve its technical problems is as follows:

[0007] An arched magnetostrictive composite array for harvesting human motion energy, which is composed of n energy harvesting units, where n = 2 to 100,000; the array is rectangular, circular or triangular circular ring-shaped, and the distance between adjacent units is 7 to 15 cm; each energy harvesting unit includes an arched magnetostrictive composite structure, a pickup coil and a bias magnet; among them, one pickup coil is wound around each end of the arched magnetostrictive composite structure; a bias magnet is fixed directly above each pickup coil;

[0008] Among them, the radius of curvature of the arch is 17 to 21 cm;

[0009] The arched magnetostrictive composite structure includes a magnetostrictive layer and a fixing layer; among them, the magnetostrictive layer is embedded inside the fixing layer;

[0010] The magnetostrictive layer is an arched magnetostrictive wire, and the material is an iron-gallium alloy; the number is 4 to 8, and they are placed side by side;

[0011] The material of the bias magnet is an N35 neodymium iron boron permanent magnet,

[0012] The iron-gallium alloy is Fe83-Ga17;

[0013] The material of the fixing layer is epoxy resin;

[0014] The length of the arched magnetostrictive composite structure is 13 to 15 cm, the width is 3 to 7 cm, and the thickness is 3 to 4 mm;

[0015] The winding length of each pickup coil is 20 to 25% of the arched length;

[0016] The length of the arched magnetostrictive wire is 11 to 13 cm, and the diameter range is 0.3 to 0.7 mm;

[0017] The size of the bias magnet is 3 cm × 5 cm × 0.5 cm;

[0018] The number of turns of the pickup coil is 500 to 700 turns, and the diameter range is 0.15 to 0.25 mm.

[0019] The essential features of the present invention are:

[0020] The magnetostrictive vibration energy harvesters in current technology generally have complex structural designs and high additional losses, which results in low energy collection efficiency of the device. For the field of human motion energy collection, low energy collection efficiency will lead to a reduction in the output signal, so it is not suitable for the field of human motion energy collection.

[0021] The present invention adopts an iron-gallium alloy with better output performance as the core component and designs an arched + arrayed integrated structure. Under the stimulation of human movement, the arched magnetostrictive composite structure will undergo drastic deformation, and the arrayed design will superimpose the output voltage, thereby comprehensively realizing a high-efficiency improvement in energy collection efficiency, which is extremely suitable for the field of human movement energy collection.

[0022] The main principle is: human body movement excitation is applied to the middle of the arched magnetostrictive composite structure. Since the arched structure has a certain curvature, the deformation of the arched magnetostrictive composite structure is more severe after being impacted compared to the straight structure. The magnetostrictive layer inside the structure will also deform violently, so that the magnetic domains inside the magnetostrictive layer are fully utilized, that is, the magnetic permeability changes, and ultimately leads to a change in magnetic flux. At the same time, the array design will further improve the energy collection efficiency of the device. According to Faraday's law of electromagnetic induction, the pickup coil will generate a larger induced voltage.

[0023] The beneficial effects of the present invention are:

[0024] 1. The present invention designs an arched structure. Since the arched structure has a certain curvature, compared with a straight structure, the arched magnetostrictive composite structure deforms more violently when the same force is applied, thereby further increasing the deformation of the structure. The increase in the deformation represents the increase in the magnetic flux of the magnetostrictive layer, and ultimately achieves an increase in the collection efficiency.

[0025] 2. Existing magnetostrictive devices for human motion energy collection face the problem of small output voltage signals. To address this core problem, the present invention adopts an arrayed structural design to superimpose multiple output voltage signals to further increase the output voltage amplitude. Compared with a patented human motion energy capture device based on Fe-Co alloy, the maximum output voltage is increased by 170%.

[0026] 3. In order to further fit the energy collection of human body movement, the present invention analyzes the law of human foot movement and designs a specific installation position according to the maximum fulcrum of foot movement. This design will be more in line with human body movement. At the same time, the present invention has small size, simple structure, and is easy to carry, which can meet the requirements of miniaturization. Description of the drawings:

[0027] Figure 1 It is a schematic structural diagram of an arched magnetostrictive composite array composed of 4 energy harvesting units;

[0028] Figure 2 is Figure 1 the front view of

[0029] Figure 3 the arched magnetostrictive composite structure diagram;

[0030] Figure 4 the schematic diagram of the mold;

[0031] Figure 5 the installation schematic diagram of the arched magnetostrictive composite array;

[0032] Figure 6 is the graph of the maximum output voltage of the composite array varying with the step frequency under human motion excitation;

[0033] In the figure: 1 - arched magnetostrictive composite structure; 2 - pickup coil; 3 - bias magnet; 4 - magnetostrictive layer; 5 - fixing layer; 6 - mold; Specific implementation manner:

[0034] The arched magnetostrictive composite array realizes vibration energy harvesting by using the inverse magnetostrictive effect and the electromagnetic induction law. When a transient excitation is applied to the middle of the composite structure, the bending deformation generated during the vibration of the magnetostrictive layer in the fixing layer causes a change in the magnetization state inside the magnetostrictive layer, that is, a change in magnetic permeability, and finally leads to a change in magnetic flux. According to Faraday's law of electromagnetic induction, the pickup coil will induce a changing magnetic field and generate an induced voltage. By integrating the inverse magnetostrictive effect and the electromagnetic induction law, the composite array can efficiently collect the energy of human motion and convert it into an output voltage.

[0035] The invention will be further described in detail below with reference to the figures. This embodiment is only a specific description of the invention and is not regarded as a limitation of the protection scope.

[0036] An arched magnetostrictive composite array for human motion energy harvesting according to the present invention, the composite array is composed of n energy harvesting units, n = 2 to 100000; the array is rectangular, circular or triangular circular ring (the spacing between units is 14 cm); the following takes n = 4 energy harvesting units involved in human foot stepping as an example for illustration, as Figure 1 shown

[0037] Each energy harvesting unit includes an arched magnetostrictive composite structure 1, a pickup coil 2 and a bias magnet 3; wherein, one pickup coil 2 is wound around each end of the arched magnetostrictive composite structure 1; a bias magnet 3 is fixed directly above each pickup coil;

[0038] Among them, the winding length of each pickup coil 2 is 25% of the arch length;

[0039] The described arched magnetostrictive composite structure 1 includes a magnetostrictive layer 4 and a fixing layer 5; among them, the magnetostrictive layer 4 is embedded inside the fixing layer 5, as Figure 3 shown;

[0040] The length of the arched magnetostrictive composite structure 1 is 14 cm, the width is 5 cm, the radius of curvature is about 19 cm, and the thickness range is 3 - 4 mm (the thickness adopted in this embodiment is 3.5 mm);

[0041] The magnetostrictive layer is an arched magnetostrictive wire, and the material is iron-gallium alloy (Fe83-Ga17); the length is 12 cm, and the diameter range is 0.3 - 0.7 mm (the thickness adopted in this embodiment is 0.5 mm); there are 6 in total, placed side by side; the radius of curvature of the arch is 19 cm;

[0042] The material of the fixing layer is epoxy resin;

[0043] The preparation process of the arched magnetostrictive composite structure is as follows:

[0044] Mix epoxy resin and curing agent in a mass ratio of 3:1, put them into a blender and stir evenly for 12 minutes, then let it stand for 10 minutes to obtain a precursor solution; then pour the precursor solution into a mold with a rectangle inside, as Figure 4 shown; the pouring depth is half of the groove depth, the groove depth is 4 mm, cure at room temperature for 6 hours, then horizontally place six Fe-Ga alloy wires on the incompletely cured precursor solution, with a spacing of about 0.8 cm between each wire, and then pour the precursor solution of the same composition into the mold 6 to cover the surface of the six Fe-Ga alloy wires and fill the groove, let it stand for 3 hours, take out the incompletely cured rectangular composite structure, apply external force to both sides of the composite structure to make it undergo uniform deformation (until the bending radius of curvature is about 19 cm), then put it into a heating box, set the temperature to 40 °C and continue to cure for 10 hours, wait until it is completely cured and take it out, cool at room temperature for 60 minutes, and obtain the arched magnetostrictive composite structure;

[0045] The described epoxy resin matrix is bisphenol A; the curing agent is polyetheramine or modified amine;

[0046] The material of the pickup coil is insulated copper enameled wire, the number of turns of the coil is 600 turns, and the diameter range is 0.15 - 0.25 mm (the thickness adopted in this embodiment is 0.2 mm);

[0047] The material of the bias magnet is N35 neodymium iron boron permanent magnet, and its size is 3 cm × 5 cm × 0.5 cm; the specific position is directly above the pickup coil, and the magnetic direction is vertically downward;

[0048] When people walk or run, the forefoot and heel touch the ground alternately and regularly, which makes the movement of the feet have obvious periodicity. The feet have acceleration in both vertical and horizontal directions. Therefore, we can clearly feel the downward pressure generated by the feet. To give a common example in life, if we often step on the insole for a long time, we will find that the soles and heels are obviously deformed, which shows that the pressure generated by the feet is large enough. This pressure is caused by the change in inertia of the lower limbs when the soles and heels contact the ground. During normal walking, the impact force generated by the soles of the feet is related to the body weight. This impact force is sometimes very large, usually between 1-2 times the body weight. Therefore, we arranged the arched magnetostrictive composite array in a 2×2 form. The forefoot and heel of each foot of a person correspond to an energy collection unit. The installation diagram is shown as follows Figure 5 As shown;

[0049] The design can be laid over a large area on special sections of jogging roads, scenic walking trails and other sports venues to fully collect the energy of human movement.

[0050] The method of use includes the following steps:

[0051] The experimenter (weight 55 kg, height 175 cm) was asked to step on the arched magnetostrictive composite array while walking, and the walking frequency of the experimenter was recorded. The data acquisition card was connected to the computer, and the voltage signal generated by the arched magnetostrictive composite array could be processed by the corresponding software to obtain accurate voltage output.

[0052] At this time, the process of the composite array is as follows: transient excitation is applied to the middle of the composite structure, and the bending deformation generated during the vibration of the magnetostrictive layer in the fixed layer causes the magnetization state inside the magnetostrictive layer to change, that is, the magnetic permeability changes, and finally leads to a change in magnetic flux. The array design will further superimpose the output voltage. By integrating the inverse magnetostrictive effect and the law of electromagnetic induction, the composite array can efficiently collect the energy of human body movement and convert it into output voltage.

[0053] The protocols and software involved in the present invention are all well-known technologies.

[0054] Data Acquisition Card (DAQ card). DAQ card, also known as acquisition card, is a hardware device. This device is responsible for collecting the voltage analog signal output by the energy harvester after being impacted and converting it into a digital signal for transmission to the computer for subsequent processing and analysis. The acquisition card is usually connected to the computer through interfaces such as PCI, PCI Express, USB, etc., providing efficient data acquisition and analysis capabilities for the experiment.

[0055] When stepping on the arched magnetostrictive composite array during walking, record the walking frequency of the experimenter while walking. Connect it to a computer through a data acquisition card, and process the voltage signal generated by the energy harvester through the DHDAS dynamic signal data acquisition system to obtain an accurate voltage signal, and obtain Figure 6 , it can be seen that: as the movement step frequency of the experimenter increases, the output voltage of the composite array gradually rises. When the step frequency is 3.5 Hz, the output voltage of the composite array is the largest, about 1270 mV. It can be seen that the array design significantly improves the energy harvesting efficiency. Compared with the patent of a human motion energy capture device based on Fe-Co alloy, the output voltage is increased by 170%. It shows that the arched magnetostrictive composite array has a good harvesting effect in the field of human motion energy harvesting.

[0056] Matters not covered by this invention are well-known technologies.

Claims

1. An arched magnetostrictive composite array for human motion energy collection, characterized by: The composite array is composed of n energy collection units, n=2-100000, and the spacing between the units is 7-15 cm; each energy collection unit includes an arched magnetostrictive composite structure, a pickup coil and a bias magnet; wherein a pickup coil is wound around each end of the arched magnetostrictive composite structure; a bias magnet is fixed directly above each pickup coil; The arched magnetostrictive composite structure comprises a magnetostrictive layer and a fixed layer; wherein the magnetostrictive layer is embedded in the fixed layer; the curvature radius of the arch is 17 to 21 cm; The magnetostrictive layer is an arched magnetostrictive wire made of an iron-gallium alloy; there are 4 to 8 of them in total, which are placed side by side.

2. The arched magnetostrictive composite array for human motion energy collection as claimed in claim 1, characterized in that: The material of the bias magnet is N35 neodymium iron boron permanent magnet. The iron-gallium alloy is Fe83-Ga17; The material of the fixing layer is epoxy resin.

3. The arched magnetostrictive composite array for human motion energy collection as claimed in claim 1, characterized in that: The length of the arched magnetostrictive composite structure is 13 to 15 cm, the width is 3 to 7 cm, and the thickness is 3 to 4 mm; The winding length of each pickup coil is 20-25% of the arch length; The length of the arched magnetostrictive wire is 11 to 13 cm, and the diameter ranges from 0.3 to 0.7 mm; The size of the bias magnet is 3cm×5cm×0.5cm; The pickup coil has 500 to 700 turns and a diameter ranging from 0.15 to 0.25 mm.

4. The arched magnetostrictive composite array for human motion energy collection as claimed in claim 1, characterized in that: The array is rectangular, circular or triangular ring-shaped; the spacing between adjacent units is 7 to 15 cm.

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