An overload self-tuning magnetic field energy harvester

Abstract

The present invention discloses an overload self-tuning magnetic field energy collector, which includes a packaging shell, a frame, a bias magnet, an energy extraction coil, a rotating device, and a mechanical tuning device. The frame is installed in the packaging shell and serves as a skeleton for winding the energy extraction coil. The bias magnet is arranged in grooves on both sides of the packaging shell, and a rotating device is installed in the frame. The mechanical tuning device is arranged on the outside of the packaging shell, and a tuning magnet is arranged above the mechanical tuning device. The overload self-tuning magnetic field energy collector described in the present invention utilizes permanent magnetic materials and does not require a magnetic focusing ring in a traditional current transformer. It can realize energy extraction from a spatial magnetic field and is more convenient to install and maintain. In addition, its overload self-tuning design can realize the function of automatically adjusting the resonant frequency of the system during operation, which not only reduces damage to the bearings, but also avoids damage to the system caused by large current shocks, effectively increasing the working bandwidth of the system.

Description

Technical Field

[0001] The invention belongs to the technical field of space magnetic field energy capture, and in particular relates to an overload self-tuning magnetic field energy collector. Background Art

[0002] With the increasing popularity of the Internet of Things (IoT), wireless sensor networks (WSNs) have garnered increasing attention in power grid monitoring systems. However, power supply issues have long constrained the application and development of sensors. Traditional wireless sensor nodes are primarily powered by batteries, but these batteries have limited capacity and are difficult to replace and maintain, making it difficult to implement regular deployment of large-scale sensor networks. In power applications, the widespread presence of 50 Hz stray magnetic fields (<1 mT or <10 Oe) around transmission / distribution lines provides a reliable energy source for wireless sensor nodes in smart grids.

[0003] A magnetic-mechanical-electric vibration energy harvester based on a cantilever beam structure is a commonly used new device for capturing power frequency magnetic field energy. While this type of harvester boasts a simple structure, high output energy density, and high electromechanical conversion efficiency, it suffers from a narrow operating frequency band and a small dynamic range, making it difficult to meet milliwatt-level power supply requirements. Magnetic field energy harvesting, based on the principle of electromagnetic induction, is currently the mainstream technology used in power sensing. Depending on the deployment method, it can be categorized as either invasive or non-invasive. Invasive harvesting, similar to conventional current transformers, offers good coupling and high power output, but suffers from poor operability and high maintenance costs. Large-scale installation on power transmission lines can introduce additional mechanical stress, leading to line degradation. Non-invasive harvesting, while non-invasive, allows for non-destructive installation without disrupting the existing system structure, resulting in improved operability and low maintenance costs. However, this method suffers from low coupling coefficients and power, making it difficult to achieve stable power supply for wireless sensor nodes. Furthermore, when the source current is excessive, the closed magnetic ring structure can lead to core saturation and overheating damage.

[0004] In 2017, researchers proposed a nonlinear resonant, high-power, industrial-frequency magnetic energy harvester capable of harvesting up to 13.5 mW of power in a 2.4 Oe (RMS) industrial-frequency AC magnetic field. However, this structure suffers from a high output Q factor, which can severely damage the bearings during operation. Furthermore, excessively strong excitation magnetic fields can cause the permanent magnets to rotate excessively, preventing normal oscillation. In real-world situations, when transient current surges exceed the rated value, such as from lightning or line shorts, the energy harvester itself and the electronic components connected to its output ports can suffer catastrophic failure and damage due to the rapidly changing voltage and current.

[0005] Considering the limitations of existing energy harvesting technology, there is an urgent need for a high-power space energy harvesting technology and an overload self-tuning method to solve the problems of narrow operating bandwidth of energy harvesters and easy damage of components under large current shocks. Summary of the Invention

[0006] In order to solve the deficiencies in the prior art, the present invention proposes an overload self-tuning magnetic field energy harvester.

[0007] The present invention adopts the following technical solutions.

[0008] The present invention discloses an overload self-tuning magnetic field energy collector, comprising a packaging shell, a frame, a bias magnet, a rotating device and a mechanical tuning device. Grooves are provided on both sides of the packaging shell, the frame is installed in the packaging shell, the bias magnets are provided in the grooves on both sides of the packaging shell, and the rotating device is installed in the frame.

[0009] The rotating device includes a permanent magnet and a guide rod, the permanent magnet is provided with a guide rod, and the guide rod abuts against the mechanical tuning device;

[0010] The mechanical tuning device includes a tuning magnet, which changes the size of the bias magnetic field applied to the rotating device by changing the number of bias magnets in the packaging shell. The mechanical tuning device changes the size of the bias magnetic field applied to the rotating device by changing the distance between the tuning magnet and the bias magnet, and is used for overload self-tuning of the system.

[0011] Preferably, the guide rod is fixed on the surface of the permanent magnet along the radius direction of the bottom circle of the permanent magnet.

[0012] Preferably, an energy extraction coil is wound around the outer periphery of the frame, and the energy extraction coil is wound around the frame using a surface-insulated copper wire.

[0013] Preferably, the rotating device further comprises a rotating shaft, the rotating shaft is longitudinally installed in the frame, and a permanent magnet is fixed on the periphery of the rotating shaft.

[0014] Preferably, the mechanical tuning device further comprises: a baffle and a crank;

[0015] A limiting slot is provided on the baffle, the crank is rotatably connected to one side of the baffle, and a cross bar is provided at one end of the crank, the cross bar is inserted into the limiting slot, and the other end of the crank is fixed with the tuning magnet.

[0016] Preferably, the crank includes a fixedly connected sleeve, a first arm and a second arm, the first arm and the second arm are located on both sides of the sleeve, the sleeve is rotatably connected to one side of the baffle, the end of the first arm can be slidably inserted into the limit slot, and the end of the second arm is fixed to the tuning magnet.

[0017] Preferably, the mechanical tuning device further comprises: a tuning magnet base, which is arranged below the tuning magnet and is used to fix the tuning magnet. The tuning magnet interacts with the bias magnet to change the magnitude of the bias magnetic field applied to the rotating device.

[0018] Preferably, the mechanical tuning device also includes: a cylinder and a sliding device, the sliding device is slidably arranged in the cylinder in a horizontal direction, the cylinder is arranged on the packaging shell, one end of the sliding device abuts against the guide rod, and the other end abuts against the crank, the rotating device drives the sliding device to move through the guide rod, and the sliding device drives the position adjustment of the tuning magnet through the crank.

[0019] Preferably, a through hole is provided at the bottom of the packaging shell, and the through hole is used to cooperate with a fastener for fixing the magnetic field energy collector.

[0020] Preferably, the mechanical tuning device further comprises a slider, a through hole is provided inside the slider, and one end of the sliding device passes through the through hole of the slider and abuts against the guide rod.

[0021] Preferably, the shape of the permanent magnet in the rotating device is any one of cylindrical, rectangular, and polygonal.

[0022] The beneficial effect of the present invention is that, compared with the prior art,

[0023] (1) The present invention discloses an overload self-tuning magnetic field energy collector with an overload self-tuning design, which is provided with a permanent magnet, a rotating device and a mechanical tuning device. When the energy collector operates at its resonant frequency of 50 Hz, the nonlinear state is extremely strong under the impact of a large current. In this state, the swing amplitude of the permanent magnet increases with the increase of the current. The permanent magnet drives the rotating device to interact with the mechanical tuning device, and changes the distance between the rotating device and the mechanical tuning device to achieve the change of the resonant frequency of the energy collector, so that the energy collector returns to a state with a smaller swing amplitude in a non-resonant state, thereby achieving the purpose of overload self-tuning and protecting the overall structure. At the same time, due to the effect of gravity, the mechanical tuning device will return to its initial state in a clockwise circular motion after approaching the rotating device at a certain distance.

[0024] It utilizes the mechanical resonance of permanent magnetic materials under torque to achieve energy conversion. It does not require the magnetic focusing ring in traditional current transformers, can realize energy extraction from the spatial magnetic field, is more convenient for installation and maintenance, and can realize the function of automatically adjusting the resonant frequency during operation of the system, which not only reduces damage to the bearings, but also avoids damage to the system caused by large current shocks.

[0025] (2) The overload self-tuning method of the magnetic field energy harvester of the present invention can suppress the nonlinear behavior of the system when it operates at the resonant frequency and can effectively increase the operating bandwidth of the system.

[0026] (3) The permanent magnet material used in the overload self-tuning magnetic field energy harvester described in this invention has a high magnetization intensity and can generate sufficient driving force to achieve resonance under a comparable volume and current excitation. Near a 1A current-carrying conductor, the open-circuit voltage of the energy harvester reaches 15V, and the matched load power reaches 1mW.

[0027] (4) The resonant frequency of the overload self-tuning magnetic field energy harvester described in the present invention can be adjusted by the position and size of the bias magnet, and resonance at 50 Hz can be easily achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0029] Figure 1 This is a schematic diagram of the overall structure of an overload self-tuning magnetic field energy harvester according to the present invention;

[0030] Figure 2 This is a schematic diagram of the internal structure of an overload self-tuning magnetic field energy harvester according to the present invention;

[0031] Figure 3 This is a schematic diagram of the overall structure of an overload self-tuning magnetic field energy harvester using a rectangular permanent magnet according to the present invention;

[0032] Figure 4 This is a schematic diagram of the overall structure of an overload self-tuning magnetic field energy harvester using a hexagonal permanent magnet according to the present invention;

[0033] Figure 5 This is a schematic diagram of the overall structure of an overload self-tuning magnetic field energy collector using a permanent magnet in the form of a polygonal body and a cylinder according to the present invention;

[0034] Figure 6 This is a schematic diagram of the overall structure of an overload self-tuning magnetic field energy harvester with a crank angle of 90° according to the present invention;

[0035] Figure 7 The comparison of output effects of an overload self-tuning magnetic field energy harvester according to the present invention and whether the overload self-tuning method is used;

[0036] Figure 8 It is a frequency sweep curve of the overload self-tuning method adopted by the overload self-tuning magnetic field energy harvester of the present invention;

[0037] Figure 9 This is a graph showing the relationship between the actual output voltage and energy-drawing power and the load next to a 1A wire of the present invention;

[0038] Figure 10 1 is a schematic diagram of the principle of an overload self-tuning magnetic field energy harvester according to the present invention, and is a top view of the energy harvester;

[0039] Figure 11 It is a front view of a principle schematic diagram of an overload self-tuning magnetic field energy harvester according to the present invention;

[0040] In the figure: 1-powered wire; 2-packaging shell; 3-frame; 4-bias magnet; 5-permanent magnet; 6-bearing No. 1; 7-rotating shaft; 8-energy extraction coil; 9-crank; 10-limiting slot; 11-horizontal rod; 12-slider; 13-guide rod; 14-tuning magnet base; 15-baffle; 16-cylinder; 17-through hole; 18-tuning magnet; 19-bearing No. 2. DETAILED DESCRIPTION

[0041] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. The embodiments described in this application are only part of the embodiments of the present invention, not all of them. Based on the spirit of the present invention, other embodiments obtained by ordinary technicians in this field without making creative efforts are all within the scope of protection of the present invention.

[0042] like Figure 1-2 As shown, the present invention provides an overload self-tuning magnetic field energy collector, which includes a packaging shell 2, a frame 3, a bias magnet 4, an energy extraction coil 8, a rotating device and a mechanical tuning device.

[0043] Among them, the packaging shell 2 is a rectangular box with grooves on both sides. The frame 3 is installed in the packaging shell 2. The frame 3 serves as a skeleton for winding the energy extraction coil 8. The bias magnet 4 is placed in the grooves on both sides of the packaging shell 2. A rotating device is installed in the frame 3. By changing the number of bias magnets 4, the bias magnetic field applied to the rotating device can be changed. The mechanical tuning device achieves the system overload self-tuning effect by changing the distance between the tuning magnet 18 and the bias magnet 4, that is, changing the size of the bias magnetic field applied to the rotating device.

[0044] The rotating device includes a permanent magnet 5, a rotating shaft 7 and a guide rod 13. The rotating shaft 7 is longitudinally installed in the frame. The permanent magnet 5 is fixed on the outer periphery of the rotating shaft 7. The guide rod 13 is fixed on the permanent magnet 5.

[0045] Specifically, the rotating device consists of a permanent magnet 5, two No. 1 bearings 6, a rotating shaft 7 and a guide rod 13, wherein the permanent magnet 5 is a cylindrical NbFeB material magnetized in the radial direction, and a through hole is set in the center of the cylinder; the rotating shaft 7 is fixed to the frame 3 through the No. 1 bearing 6, and is arranged in the through hole of the cylindrical permanent magnet 5 for tight fit; the guide rod 13 is fixed on the surface of the permanent magnet 5, along the radius of the bottom circle of the permanent magnet 5.

[0046] The frame 3 is used to install the No. 1 bearing 6 and serves as the skeleton of the energy extraction coil 8.

[0047] In a preferred but non-limiting embodiment of the present invention, the energy harvesting coil 8 is tightly wound around the frame using surface-insulated copper wire, and when the magnetic field in the environment excites the permanent magnet to resonate, the energy harvesting coil 8 can generate a signal output.

[0048] A groove for placing the bias magnet 4 is left on the packaging shell 2, and a mechanical tuning device is set up at one end, which includes a crank 9, a horizontal rod 11, a slider 12, a tuning magnet base 14, a baffle 15, a cylinder 16 and a tuning magnet 18; the horizontal rod 11 passes through the cylinder 16, and the slider 12 is fixed to one end near the guide rod. The crank 9 is installed on the baffle 15, and a limiting slot 10 is provided on the baffle 15. The crank 9 is provided with two rods, one end of the lower rod passes through the limiting slot 10, and one end of the upper rod is fixed with a bias magnet base 14, and the bias magnet 4 is fixed on the bias magnet base.

[0049] Specifically, the mechanical tuning device consists of a baffle 15, a tuning magnet base 14, a crank 9, a cylinder 16, a tuning magnet 18, a No. 2 bearing 19, a horizontal rod 11 and a slider 12;

[0050] Among them, a limiting groove 10 is provided on the baffle 15, the No. 2 bearing 19 is installed on the baffle 15, the crank 9 is sleeved on the outer wheel of the No. 2 bearing 19 and the lower cross bar is inserted into the limiting groove 10, the No. 2 bearing 19 fixes the crank 9 outside, and the tuning magnet base 14 on the upper cross bar is pasted with a tuning magnet 18. The horizontal rod 11 and the slider 12 constitute a sliding device, which is horizontally penetrated into the tube 16 on the packaging shell 2. One end of the sliding device abuts against the guide rod 13, and the other end abuts against the crank 9. The rotating device drives the sliding device to move through the guide rod 13, and the sliding device drives the position adjustment of the tuning magnet 18 through the crank 9.

[0051] More specifically, the crank 9 includes a fixedly connected sleeve, a first arm and a second arm. The first arm and the second arm are located on both sides of the sleeve. The sleeve is rotatably connected to one side of the baffle. The end of the first arm can be slidably inserted into the limit slot 10, and the end of the second arm is fixed to the tuning magnet 18.

[0052] A through hole is provided inside the slider 12 , and one end of the sliding device passes through the through hole of the slider 12 and abuts against the guide rod 13 .

[0053] In a preferred but non-limiting embodiment of the present invention, the permanent magnet is magnetized radially, the bias magnetic field and the tuning magnetic field are provided by cylindrical or rectangular magnets, and both the bias magnet and the tuning magnet are magnetized along the thickness direction.

[0054] Further preferably, the permanent magnet, bias magnet and tuning magnet are all made of permanent magnetic materials, and the material is one of NdFeB, SmCo, AlNiCo and permanent ferrite.

[0055] The energy collector further comprises a through hole 17 for cooperating with a fastener for fixing the magnetic field energy collector.

[0056] In a preferred but non-limiting embodiment of the present invention, the No. 1 bearing 6 and the No. 2 bearing 19 may include one of commonly used zirconia ceramics, plastics, bearing steel, stainless steel and low-carbon steel, and may also include other materials that are not easily magnetized, such as copper, aluminum, silver, etc.

[0057] The packaging shell, frame, rotating shaft, guide rod, slider, horizontal rod and crank are made by 3D printing technology or machined from aluminum alloy.

[0058] The resonant frequency of the overload self-tuning method of the overload self-tuning magnetic field energy collector described in the present invention is positively correlated with the applied bias magnetic field. When the energy collector operates at its resonant frequency of 50Hz, the nonlinear state is extremely strong under large current impact. In this state, the swing amplitude of the permanent magnet will increase with the increase of current. After exceeding a certain angle, the guide rod 13 fixedly bonded to the permanent magnet 5 will collide with the slider 12 during the swinging process, applying a horizontal thrust to the slider 12, causing the slider 12 to move to the right together with the horizontal rod 11 fixedly connected to it. The horizontal rod 11 transmits force to the crank 9 during the movement. After being subjected to the force, the crank 9 rotates counterclockwise. At the same time, the tuning magnet 18 at the upper end of the crank 9 approaches the rotating device of the energy collector, changing The size of the energy collector's bias magnetic field has changed, that is, the resonant frequency of the energy collector has changed. At this time, the energy collector returns to a state with a smaller swing amplitude in the non-resonant state, so as to achieve the purpose of overload self-tuning and protection of the overall structure. At the same time, due to the effect of gravity, the tuning magnet 18 will return to its initial state in a clockwise circular motion after approaching the rotating device for a certain distance. During this process, the crank 9 exerts a clockwise circular motion on the horizontal rod 11 to the left, causing the horizontal rod 11 and the slider 12 fixed to it to move horizontally to the left together, returning to the initial state before the guide rod 13 collides with the slider 12. As the slider 12, crank 9, etc. return to their initial positions, the resonant frequency of the energy collector also returns to 50Hz. When faced with a persistent high current or another high current shock, the mechanical tuning device of the energy collector will repeat the above process.

[0059] like Figure 3-5 As shown, in a preferred but non-limiting embodiment of the present invention, the shape of the permanent magnet 5 in the rotating device can be one of cylindrical, rectangular, polygonal, or a combination of the three, and is placed at the center of the rotating shaft 7.

[0060] The bias magnet 4 placed on the packaging shell 2 introduces a constrained magnetic torque to the energy collector, so that the permanent magnet 5 is always in an equilibrium position when there is no excitation magnetic field.

[0061] like Figure 6 As shown, the angle of the upper limit groove 10 on the baffle 15 and the included angle on the crank 9 can be changed according to specific conditions and requirements.

[0062] Example 1:

[0063] The energy taking coil 8 is tightly wound with copper enameled wire of 200 μm in diameter, with multiple layers and 500 turns.

[0064] The material of the permanent magnet 5 is the strongest grade of neodymium iron boron magnet N52. The permanent magnet 5 is cylindrical with a through hole in the middle. The overall dimensions are: bottom diameter 14mm, height 19mm, and the diameter of the bottom center through hole is 7.1mm.

[0065] The materials of bearing No. 1 6 and bearing No. 2 19 are both made of zirconia ceramics, with an outer diameter of 10 mm, an inner diameter of 5 mm, and a height of 4 mm. The energy-taking coil 8 wound on the frame 3 is fixed with 502 glue.

[0066] The angle between the two rods on the crank 9 is 150°, and the initial position is as follows Figure 1 shown.

[0067] Taking the vertical symmetry axis of the baffle 15 as the 0° reference line, the angle of the limiting groove 10 is from -27° to 27°.

[0068] The packaging shell 2, the frame 3, the rotating shaft 7, the guide rod 13, the slider 12, the horizontal rod 11 and the crank 9 are manufactured by 3D printing technology or machined from aluminum alloy.

[0069] Figure 7 The output effect comparison between this embodiment and whether the overload self-tuning method is used is shown. It can be seen that the proposed overload self-tuning method has a significant inhibitory effect on the nonlinear behavior of the energy harvester and can work stably under strong magnetic field excitation.

[0070] Figure 8 This is a frequency sweep curve measured by the overload self-tuning method in this embodiment, which illustrates that the mechanical tuning mechanism proposed in the present invention can effectively increase the operating bandwidth of the system.

[0071] Figure 9 : This is a graph showing the relationship between the output voltage and energy extraction power of this embodiment at a 1A wire and changes in load. It can be seen from the graph that its peak-to-peak open-circuit voltage is close to 10V; under a purely resistive load of 10kΩ, its optimal output power reaches 1.2mW.

[0072] The overload self-tuning magnetic field energy collector described in the present invention does not require the magnetic focusing ring in the traditional current transformer to achieve energy extraction from the spatial magnetic field, which is more convenient for installation and maintenance; secondly, the residual magnetization intensity of the swinging permanent magnet material used is high, and under small current excitation, it can generate sufficient driving force to achieve resonance, thereby reducing the starting current threshold of the traditional current transformer; in addition, the mechanical tuning mechanism of the energy collector can timely change the applied bias magnetic field when the excitation is overloaded, thereby realizing the self-tuning function.

[0073] To further increase the output power of the overload self-tuning magnetic field energy harvester, multiple permanent magnet magnetic field energy harvesters can be connected in parallel and arranged linearly around the conductor. To address the problem of excessive swing amplitude of the permanent magnets during high currents, which can easily lead to structural damage, an overload self-tuning method is designed to automatically reduce the resonant frequency of the energy harvester when the swing amplitude of the permanent magnets exceeds a certain range. Furthermore, considering the energy harvester's operating state and errors in processing and installation, the overload self-tuning magnetic field energy harvester can produce vertical vibrations, affecting the ultimate energy extraction efficiency.

[0074] like Figure 11 As shown, the working principle of the overload self-tuning method of the overload self-tuning magnetic field energy harvester is as follows: when the energy harvester is working, a DC bias magnetic field needs to be applied to it to provide a constrained magnetic torque on the permanent magnet so that the permanent magnet 5 is kept in a balanced position, such as Figure 10 At the horizontal dotted line position shown, when the energy collector is placed around the current-carrying conductor 1, the AC magnetic field generated around the current-carrying conductor 1 will apply an AC magnetic torque to the energy collector, and the torque mode excitation will be applied to the magnetic moment of the permanent magnet 5, causing the permanent magnet 5 to swing left and right around its equilibrium position. The equilibrium magnetization direction of the permanent magnet 5 in the energy collector is parallel to the plane of the energy extraction coil 8, which makes the relative movement between the permanent magnet 5 and the energy extraction coil 8 greater, and the cylindrical permanent magnet 5 makes the oscillating magnetic field stronger and more uniform. This design greatly improves the coupling effect between the coil and the oscillating magnetic field, and realizes the function of obtaining high output power at the output port of the coil.

[0075] As the coupling effect between the coil and the oscillating magnetic field in the energy harvester increases, a large current shock will cause the permanent magnet 5 to swing too much, resulting in a sudden change in the output voltage / current of the energy harvesting device, and catastrophic failure and damage to the energy harvester itself and the electronic devices at its output port. To solve this problem, a mechanical tuning structure is added to the original framework. When the swing amplitude of the permanent magnet 5 exceeds a certain range, this tuning structure can automatically reduce the resonant frequency of the energy harvester, that is, overload self-tuning. This tuning method can also effectively increase the operating bandwidth of the energy harvesting device.

[0076] The design idea of ​​the overload self-tuning method is as follows: According to existing research, the resonant frequency of the energy harvester is positively correlated with the applied bias magnetic field. When the energy harvester operates at a frequency of 50 Hz, the nonlinear state is extremely strong under the impact of large current. In this state, the swing amplitude of the permanent magnet exceeds a certain range, which will trigger the tuning mechanism to work. The tuning mechanism reduces the resonant frequency of the energy harvester by reducing the size of the bias magnetic field, so that it returns to the state where the swing amplitude of the permanent magnet 5 is smaller when it is non-resonant, thereby achieving the purpose of protecting the overall structure.

[0077] The present invention also provides a method for preparing an overload self-tuning magnetic field energy harvester, comprising the following steps:

[0078] Step 1: Mechanical design: 3D print the package shell 2, frame 3, shaft 7, guide rod 13, slider 12, horizontal rod 11 and crank 9;

[0079] Step 2: Assemble the rotating device: Pass the rotating shaft 7 through the through hole in the center of the permanent magnet 5, connect the No. 1 bearing 6 to the two ends of the rotating shaft 7, and stick the guide rod 13 on the permanent magnet 5 to form the rotating device;

[0080] In a preferred but non-limiting embodiment of the present invention, step 2 specifically comprises:

[0081] Step 2.1: Pass the rotating shaft 7 through the through hole in the center of the rotating magnet, so that the permanent magnet 5 is located at its center, and use 502 or double-sided tape to tightly connect them;

[0082] Step 2.2: Assemble the rotating device consisting of the rotating shaft 7, the permanent magnet 5, and the No. 1 bearing 6, so that the rotating shaft 7 and the permanent magnet 5, as well as the rotating shaft 7 and the No. 1 bearing 6 are tightly connected;

[0083] Step 2.3: Use 502 glue to stick the guide rod 13 to the appropriate position on the permanent magnet 5.

[0084] Step 3: Assemble the mechanical tuning device: Pass the horizontal rod 11 through the cylinder 16 and glue it to the slider 12. Connect the baffle 15 to the second bearing 19, and connect the second bearing 19 to the crank 9. Insert one end of the crank 9 into the limit slot of the baffle 15. Glue and fix the tuning magnet 18 to the tuning magnet base 14 of the crank 9.

[0085] In a preferred but non-limiting embodiment of the present invention, step 3 specifically comprises:

[0086] Step 3.1: Pass the horizontal rod 11 through the cylinder 16 and fix it to the slider 12;

[0087] Step 3.2: Assemble the baffle 15, the second bearing 19, and the crank 9 so that the baffle 15 and the second bearing 19, and the second bearing 19 and the crank 9 are tightly connected, and one end of the crank 9 is inserted into the retaining groove of the baffle 15;

[0088] Step 3.3: Glue and fix the tuning magnet 18 on the tuning magnet base 14 of the crank 9.

[0089] Step 4: Assemble the energy collector: install and fix the rotating device in the frame 3, set the mechanical tuning device on one side of the rotating device, evenly wind the energy collection coil 8 on the frame 3, install the packaging shell 2 outside the frame 3 with the energy collection coil 8 wound around it, place the bias magnet 4 on both sides of the packaging shell 2, and finally fix the entire device through the through hole 17 to form a magnetic field energy collector.

[0090] The beneficial effect of the present invention is that, compared with the prior art,

[0091] (1) The present invention discloses an overload self-tuning magnetic field energy collector, which is provided with a permanent magnet, a rotating device and a mechanical tuning device. When the energy collector operates at its resonant frequency of 50 Hz, the nonlinear state is extremely strong under the impact of large current. In this state, the swing amplitude of the permanent magnet increases with the increase of current. The permanent magnet drives the rotating device to interact with the mechanical tuning device, and changes the distance between the rotating device and the mechanical tuning device to achieve the change of the resonant frequency of the energy collector, so that the energy collector returns to the state with a smaller swing amplitude in the non-resonant state, thereby achieving the purpose of overload self-tuning and protecting the overall structure. At the same time, due to the effect of gravity, the mechanical tuning device will return to the initial state in a clockwise circular motion after approaching the rotating device at a certain distance;

[0092] It utilizes the mechanical resonance of permanent magnetic materials under torque to achieve energy conversion. It does not require the magnetic focusing ring in traditional current transformers, can realize energy extraction from the spatial magnetic field, is more convenient for installation and maintenance, and can realize the function of automatically adjusting the resonant frequency during operation of the system, which not only reduces damage to the bearings, but also avoids damage to the system caused by large current shocks.

[0093] (2) The overload self-tuning method of the magnetic field energy harvester of the present invention can suppress the nonlinear behavior of the system when it operates at the resonant frequency and can effectively increase the operating bandwidth of the system.

[0094] (3) The permanent magnet material used in the overload self-tuning magnetic field energy harvester described in this invention has a high magnetization intensity and can generate sufficient driving force to achieve resonance under a comparable volume and current excitation. Near a 1A current-carrying conductor, the open-circuit voltage of the energy harvester reaches 15V, and the matched load power reaches 1mW.

[0095] (4) The resonant frequency of the overload self-tuning magnetic field energy harvester described in the present invention can be adjusted by the position and size of the bias magnet, and resonance at 50 Hz can be easily achieved.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. An overload self-tuning magnetic field energy harvester, characterized by: The invention comprises a packaging shell (2), a frame (3), a bias magnet (4), a rotating device and a mechanical tuning device, wherein grooves are provided on both sides of the packaging shell (2), the frame (3) is installed in the packaging shell (2), the bias magnet (4) is provided in the grooves on both sides of the packaging shell (2), and the rotating device is installed in the frame (3); The rotating device comprises a permanent magnet (5) and a guide rod (13), the permanent magnet (5) is provided with a guide rod (13), and the guide rod (13) abuts against the mechanical tuning device; The mechanical tuning device includes a tuning magnet (18), which changes the magnitude of the bias magnetic field applied to the rotating device by changing the number of bias magnets (4) in the packaging shell (2). The mechanical tuning device changes the magnitude of the bias magnetic field applied to the rotating device by changing the distance between the tuning magnet (18) and the bias magnet (4), and is used for overload self-tuning of the system. The mechanical tuning device further comprises: a baffle (15) and a crank (9); A limiting slot (10) is provided on the baffle (15), the crank (9) is rotatably connected to one side of the baffle (15), and a crossbar is provided at one end of the crank (9), which is inserted into the limiting slot (10); the other end of the crank (9) is fixed with a tuning magnet (18); The crank (9) comprises a fixedly connected sleeve, a first arm and a second arm, the first arm and the second arm being located on both sides of the sleeve, the sleeve being rotatably connected to one side of the baffle, the end of the first arm being slidably inserted into the limiting groove (10), and the end of the second arm being fixed to the tuning magnet (18).

2. The overload self-tuning magnetic field energy harvester according to claim 1, characterized in that: The guide rod (13) is fixed on the surface of the permanent magnet (5) along the radial direction of the bottom circle of the permanent magnet (5).

3. The overload self-tuning magnetic field energy harvester according to claim 1, characterized in that: An energy extraction coil (8) is wound around the outer periphery of the frame (3), and the energy extraction coil (8) is wound around the frame using a surface-insulated copper wire.

4. The overload self-tuning magnetic field energy harvester according to claim 1, characterized in that: The rotating device further comprises a rotating shaft (7), the rotating shaft (7) being longitudinally mounted in the frame (3), and a permanent magnet (5) being fixed on the outer periphery of the rotating shaft (7).

5. The overload self-tuning magnetic field energy harvester according to claim 1, characterized in that: The mechanical tuning device further comprises a tuning magnet base (14), wherein the tuning magnet base (14) is arranged below the tuning magnet (18) and is used to fix the tuning magnet (18), and the tuning magnet (18) interacts with the bias magnet (4) to change the magnitude of the bias magnetic field applied to the rotating device.

6. The overload self-tuning magnetic field energy harvester according to claim 1, characterized in that: The mechanical tuning device further comprises: a cylinder (16) and a sliding device, wherein the sliding device is slidably arranged in the cylinder (16) in a horizontal direction, and the cylinder (16) is arranged on the packaging shell (2). One end of the sliding device abuts against the guide rod (13), and the other end abuts against the crank (9). The rotating device drives the sliding device to move through the guide rod (13), and the sliding device drives the position adjustment of the tuning magnet (18) through the crank (9).

7. The overload self-tuning magnetic field energy harvester according to claim 1, characterized in that: A through hole (17) is provided at the bottom of the packaging shell (2), and the through hole (17) is used to cooperate with a fastener for fixing the magnetic field energy collector.

8. The overload self-tuning magnetic field energy harvester according to claim 6, characterized in that: The mechanical tuning device further comprises a slider (12), a through hole being provided inside the slider (12), and one end of the sliding device passes through the through hole of the slider (12) and abuts against the guide rod (13).

9. The overload self-tuning magnetic field energy harvester according to claim 1, characterized in that: The shape of the permanent magnet (5) in the rotating device is any one of a cylindrical shape, a rectangular parallelepiped shape, and a polygonal shape.

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