Broadband low-frequency electromagnetic energy collector based on planar elastic structure

Abstract

The invention discloses a broadband low-frequency electromagnetic energy collector based on a planar elastic structure, which adopts two stacked planar elastic devices, is suitable for low-frequency environment vibration and has the characteristic of broadband. The magnetic field of one half of the magnet arranged on the central pivot is upward, and the other half of the magnet is downward, so that the change of magnetic flux intercepted by the coil in the oscillation process is enhanced, and the voltage generation efficiency is improved. Meanwhile, a magnet array and a coil are arranged in an internal space between the two planar elastic structures, a reasonable and compact structural layout is constructed, consistent output voltage and power signals are achieved in a large bandwidth of 10-30 Hz, remarkable power output can be provided, and efficient energy conversion capacity is achieved in a wide frequency range.

Description

Technical Field

[0001] The invention belongs to the field of electromagnetic energy collectors, and in particular relates to a broadband low-frequency electromagnetic energy collector based on a planar elastic structure. Background Art

[0002] In the field of electromagnetic energy harvesters, traditional battery-powered power sources are challenged by their limited lifespan and potential environmental pollution. People are beginning to seek sustainable, maintenance-free, and environmentally friendly power supply methods, namely energy harvesting technology. Among them, electromagnetic, electrostatic, piezoelectric, and hybrid energy harvesters are several common energy conversion principles used to harvest energy from environmental vibrations.

[0003] Low-frequency vibration is one of the most common recyclable energy sources. Compared with electrostatic or piezoelectric energy harvesting devices, electromagnetic energy harvesters excel in terms of energy harvesting. Electromagnetic energy harvesters in the prior art are usually large in size and are not suitable for use in limited spaces. They require large displacements to increase the working area and require high excitation amplitudes to trigger oscillations and recover sufficient power. At low vibration frequencies, it is difficult to balance the compactness of the structure and energy density. Summary of the invention

[0004] The purpose of the present invention is to provide a broadband low-frequency electromagnetic energy collector based on a planar elastic structure to solve the problem that the electromagnetic energy collector in the prior art is difficult to achieve both structural compactness and energy density at low vibration frequencies.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions to achieve the above problems:

[0006] A broadband low-frequency electromagnetic energy collector based on a planar elastic structure comprises a first planar elastic device and a second planar elastic device of the same shape, wherein the first planar elastic device and the second planar elastic device are coaxially fixedly connected via a vertical central pivot;

[0007] The first plane elastic device is made of non-rigid material and comprises an annular frame, wherein a circular vibration response platform is coaxially arranged on the inner circle of the annular frame, and the vibration response platform is installed inside the annular frame through a plurality of connecting arms distributed at equal angles;

[0008] The upper and lower ends of the central pivot are respectively fixed with a vibration response platform that penetrates the first planar elastic device and the second planar elastic device, and the middle part of the central pivot is fixedly sleeved with a magnet array, and the magnet array includes a plurality of annular permanent magnets that are sleeved in parallel from top to bottom in the middle part of the central pivot, and the magnetic field direction of the permanent magnets in the upper half of the magnet array is opposite to the magnetic field direction of the permanent magnets in the lower half;

[0009] A fixed coil is sleeved outside the magnet array, an annular space exists between the coil and the magnet array, and the height of the coil is smaller than the height of the magnet array.

[0010] The present invention also has the following features:

[0011] Furthermore, it also includes a rigid bracket; the rigid bracket includes three support members evenly distributed between two annular frames, each support member is connected to a fixing member extending toward the central axis of the central pivot;

[0012] The coil is fixedly sleeved outside the magnet array through the three fixing members.

[0013] Furthermore, a mounting groove is provided on the fixing member near the magnet array, and the coil can be fixedly mounted inside the mounting groove.

[0014] Furthermore, the first planar elastic device, the second planar elastic device and the central pivot are all made of carbon fiber reinforced nylon material.

[0015] Furthermore, vertical threaded holes are provided at the upper and lower parts of the support members, through-going connecting screw holes are provided at corresponding positions of the two annular frames, and the upper and lower ends of the three support members are respectively threadedly connected to the two annular frames.

[0016] Furthermore, the upper and lower ends of the magnet array are fixedly connected with counterweight blocks.

[0017] Furthermore, the permanent magnet is a neodymium iron boron magnet.

[0018] Compared with the prior art, the present invention has the following technical effects:

[0019] (I) The broadband low-frequency electromagnetic energy collector based on a planar elastic structure of the present invention adopts two stacked planar elastic devices, is suitable for low-frequency environmental vibrations, and has wide-band characteristics. The magnetic field of half of the magnets is set upward on the central pivot, and the other half is set downward, which enhances the change of magnetic flux intercepted by the coil during the oscillation process, thereby improving the voltage generation efficiency. At the same time, the internal space between the two planar elastic structures is used to arrange the magnet array and the coil, constructing a reasonable and compact structural layout, which has a consistent output voltage and power signal within a large bandwidth of 10 to 30 Hz, and can provide significant power output, and has efficient energy conversion capabilities within a wide frequency range.

[0020] (II) The broadband low-frequency electromagnetic energy collector based on a planar elastic structure of the present invention installs the coil by a rigid bracket with three fixing parts, which not only increases the flexibility of the overall structure, but also avoids the planar elastic device, further enhancing the reliability of the overall structure, and is suitable for large-scale use and promotion in industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the overall structure of the broadband low-frequency electromagnetic energy collector based on a planar elastic structure of the present invention;

[0022] Figure 2 is a cross-sectional view of a broadband low-frequency electromagnetic energy collector based on a planar elastic structure of the present invention;

[0023] Figure 3 is a top view of the first planar elastic device of the present invention;

[0024] Figure 4 The working principle diagram of the broadband low-frequency electromagnetic energy collector based on the planar elastic structure of the present invention;

[0025] Figure 5 Schematic diagram of the distribution of permanent magnets in the magnet array of the present invention.

[0026] The meaning of the symbols in the figure is:

[0027] 1. First plane elastic device; 2. Second plane elastic device; 3. Central pivot; 4. Ring frame; 5. Vibration response platform; 6. Connecting arm; 7. Magnet array; 8. Coil; 9. Rigid bracket; 10. Support member; 11. Fixing member; 12. Counterweight block. DETAILED DESCRIPTION

[0028] It should be noted that, unless otherwise specified, all components in the present invention are components known in the prior art, for example, the permanent magnets are known and commonly used permanent magnets.

[0029] Specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical solution of this application fall within the protection scope of the present invention.

[0030] like Figures 1 to 3 As shown, a broadband low-frequency electromagnetic energy collector based on a planar elastic structure comprises a first planar elastic device 1 and a second planar elastic device 2 of the same shape, wherein the first planar elastic device 1 and the second planar elastic device 2 are coaxially fixedly connected via a vertical central pivot 3;

[0031] The first plane elastic device 1 comprises an annular frame 4, the inner circle of which is coaxially provided with a circular vibration response platform 5, and the vibration response platform 5 is installed inside the annular frame 4 through a plurality of connecting arms 6 distributed at equal angles and intervals;

[0032] The upper and lower ends of the central pivot 3 are respectively fixed with a vibration response platform 5 that penetrates the first planar elastic device 1 and the second planar elastic device 2. A magnet array 7 is sleeved in the middle of the central pivot 3. The magnet array 7 includes a plurality of annular permanent magnets that are sleeved in parallel from top to bottom in the middle of the central pivot 3. The magnetic field direction of the permanent magnets in the upper half of the magnet array 7 is opposite to that of the permanent magnets in the lower half.

[0033] A fixed coil 8 is sleeved outside the magnet array 7 , and an annular space exists between the coil 8 and the magnet array 7 . The height of the coil 8 is smaller than the height of the magnet array 7 .

[0034] The gap between the coil 8 and the permanent magnets in the magnet array 7 is as small as possible, but it cannot be so small as to cause contact and affect the normal up and down vibration of the permanent magnets.

[0035] When the device is in use, it is necessary to apply oscillation excitation to the whole device. When the external vibration source generates an oscillating force acting on the broadband low-frequency electromagnetic energy collector based on the planar elastic structure of this embodiment, the oscillating force is transmitted to the two vibration response platforms 5, and the connecting arm 6 in the vibration response platform 5 vibrates up and down. The working process of the magnet array 7 when in use is as follows: Figure 4 As shown, the magnet array 7 is driven to reciprocate vertically relative to the coil 8. At this time, the magnetic flux in the coil 8 changes. According to Faraday's law of electromagnetic induction, the change in magnetic flux will generate an induced electromotive force in the coil 8, and finally the generated energy is stored through an external energy storage device to complete the energy collection work.

[0036] The external energy storage device may be a capacitor, and the connection method between the external energy storage and the coil 8 is well known in the prior art.

[0037] In the magnet array 7 of this embodiment, the magnetic field of half of the magnets is upward and the magnetic field of the other half is downward, which helps to produce a sudden change in magnetic flux during oscillation, thereby enhancing the electromotive force induced in the coil 8. The ground-opposed bipolar magnet configuration shows a higher magnetic flux change at small displacements (±3mm) compared to the standard configuration (a configuration in which all magnets have the same magnetic orientation), which helps to improve energy conversion efficiency and maintain good performance even when far away from its natural frequency.

[0038] The coil 8 is mounted and fixed on a rigid bracket 9. When the magnet array 7 moves axially, the coil 8 will intercept the change in magnetic flux caused by the movement of the magnets. The damping of the system includes mechanical damping and electromagnetic damping (caused by the energy conversion stage).

[0039] Among them, a supporting structure can be arranged at the lower part of the first planar elastic device 1, and the supporting structure plays a supporting and stabilizing role, which is beneficial to improving the stability of the overall device.

[0040] A more specific implementation is given below:

[0041] The height of the coil 8 is equal to one third of the maximum displacement of the magnet array 7, so as to achieve a significant output voltage signal at a low excitation amplitude and away from the first natural frequency. It should be noted that the maximum displacement of the magnet array 7 is determined according to conventional knowledge in the art.

[0042] In this embodiment, the height of the coil 8 is 6 mm. Under an excitation amplitude of 0.6 mm (the amplitude of the up and down fluctuation of the magnet array 7), a maximum output power of 5 mW can be achieved, and the peak excitation frequency is 15 Hz.

[0043] According to the maximum output power, the power reaches the average level of traditional electromagnetic energy harvesters, but on this basis, the power density reaches 2.2μW [(m / s 2 )2cm 3 ]^-1, the power density of traditional electromagnetic energy harvesters is concentrated at 2μW[(m / s 2 )2cm 3 ]^-1 or less, the power density has a significant advantage over traditional devices. In addition, the response frequency of existing electromagnetic energy harvesters can rarely be between 10-30Hz;

[0044] In the field of electromagnetic energy harvesters, the response frequency of 10-30Hz is suitable for mechanical structure vibration and vehicle vibration; within 10Hz, it is more suitable for human body vibration energy collection; above 30hz is suitable for equipment with very high vibration frequency; this device can be installed on an adapted engine to compensate and recover the engine energy to a certain extent.

[0045] As a preferred solution, it also includes a rigid bracket 9; the rigid bracket 9 includes three support members 10 evenly distributed between the two annular frames 4, and the support members 10 are connected to a fixing member 11 extending toward the central axis of the central pivot 3;

[0046] The coil 8 is fixedly mounted outside the magnet array 7 via three fixing members.

[0047] Further preferably, a mounting groove is provided at a position of the fixing member 11 close to the magnet array 7, and the coil 8 can be fixedly mounted in the mounting groove, thereby increasing the mounting strength of the coil 8 and enhancing the reliability of the overall device.

[0048] As a preferred solution, the first planar elastic device 1, the second planar elastic device 2 and the central pivot 3 are all made of carbon fiber reinforced nylon material, and in actual use, can be manufactured by 3D printing technology.

[0049] As a preferred solution, vertical threaded holes are provided at the upper and lower parts of the support member 10, through connection holes are provided at corresponding positions of the two annular frames 4, and the upper and lower ends of the three support members 10 are respectively screwed to the two annular frames 4.

[0050] As a preferred solution, counterweights 12 are fixedly connected to the upper and lower ends of the magnet array 7 .

[0051] Two counterweights 12 are symmetrically mounted on the central pivot 3 to increase the oscillation inertia of the device during operation and improve the energy collection efficiency.

[0052] Specifically, the permanent magnet is a neodymium iron boron magnet.

Claims

1. A broadband low-frequency electromagnetic energy harvester based on a planar elastic structure, characterized in that: It comprises a first plane elastic device (1) and a second plane elastic device (2) of the same shape, wherein the first plane elastic device (1) and the second plane elastic device (2) are coaxially fixedly connected via a vertical central pivot (3); The first planar elastic device (1) is made of non-rigid material and comprises an annular frame (4), the inner ring of which is coaxially provided with a circular vibration response platform (5), and the vibration response platform (5) is installed inside the annular frame (4) via a plurality of connecting arms (6) distributed at equal angles; The upper and lower ends of the central pivot (3) are respectively fixed with a vibration response platform (5) penetrating the first planar elastic device (1) and the second planar elastic device (2); the middle part of the central pivot (3) is fixedly sleeved with a magnet array (7); the magnet array (7) comprises a plurality of annular permanent magnets sleeved in parallel from top to bottom in the middle part of the central pivot (3); the magnetic field direction of the permanent magnets in the upper half of the magnet array (7) is opposite to the magnetic field direction of the permanent magnets in the lower half; A fixed coil (8) is sleeved outside the magnet array (7), an annular space exists between the coil (8) and the magnet array (7), and the height of the coil (8) is smaller than the height of the magnet array (7).

2. The broadband low-frequency electromagnetic energy collector based on a planar elastic structure according to claim 1, characterized in that: It also includes a rigid support (9); the rigid support (9) includes three support members (10) evenly distributed between the two annular frames (4), each support member (10) is connected to a fixing member (11) extending toward the central axis of the central pivot (3); The coil (8) is fixedly sleeved outside the magnet array (7) via the three fixing members (11).

3. The broadband low-frequency electromagnetic energy collector based on a planar elastic structure as claimed in claim 2, characterized in that: The fixing member (11) is provided with a mounting groove at a position close to the magnet array (7), and the coil (8) can be fixedly mounted in the mounting groove.

4. The broadband low-frequency electromagnetic energy collector based on a planar elastic structure according to claim 1, characterized in that: The first plane elastic device (1), the second plane elastic device (2) and the central pivot (3) are all made of carbon fiber reinforced nylon material.

5. The broadband low-frequency electromagnetic energy collector based on a planar elastic structure as claimed in claim 2, characterized in that: The upper and lower parts of the support member (10) are provided with vertical threaded holes, and the two annular frames (4) are provided with through connection screw holes at corresponding positions. The upper and lower ends of the three support members (10) are respectively screwed to the two annular frames (4).

6. The broadband low-frequency electromagnetic energy collector based on a planar elastic structure according to claim 1, characterized in that: The upper and lower ends of the magnet array (7) are fixedly connected with counterweight blocks (12).

7. The broadband low-frequency electromagnetic energy collector based on a planar elastic structure according to claims 1 to 6, characterized in that: The permanent magnet is a neodymium iron boron magnet.

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