An electromagnetic-piezoelectric differential energy harvesting device based on magnetostriction

Abstract

The application discloses a kind of electromagnetic-piezoelectric differential energy acquisition devices based on magnetostrictive, including first stator layer, second rotor layer and third stator layer from top to bottom stacked arrangement, the first stator layer is coaxially arranged with third stator layer, and the relative surface of two discs is symmetrically arranged with multiple composite energy trapping units;Multiple groups of axial magnetization permanent magnets are embedded in the second rotor layer;The composite energy trapping unit includes the magnetostrictive rod as the magnetic core, piezoelectric film is attached to the surface of the magnetostrictive rod.When the second rotor layer rotates, the dynamic magnetic field generated by the permanent magnet drives the magnetostrictive rod to produce axial strain, while exciting the piezoelectric conversion layer to generate electric signal;By differentially connecting the composite energy trapping units in corresponding positions in the first stator layer and third stator layer, the phase difference between signals is used to realize effective output doubling and suppress environmental interference noise.

Description

Technical Field

[0001] This invention relates to the field of micro-energy harvesting and self-powered sensing technology, specifically to an electromagnetic-piezoelectric differential energy harvesting device based on magnetostriction. Background Technology

[0002] With the explosive growth of the Internet of Things (IoT) and smart wearable technologies, the power consumption of microelectronic systems has been significantly reduced, but battery life remains a bottleneck restricting their large-scale application. Traditional chemical batteries have limitations such as large size, frequent charging, limited lifespan, and environmental pollution. Therefore, designing wearable energy harvesting devices to collect environmental vibration energy and convert it into electrical energy, thereby achieving self-powering of microsystems, has become a current research hotspot. However, most current wearable energy harvesting devices suffer from problems such as limited size, low energy conversion efficiency, narrow frequency bandwidth, and susceptibility to environmental electromagnetic interference. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention proposes an electromagnetic-piezoelectric differential energy harvesting device based on magnetostriction. This device can efficiently achieve reliable energy supply under extremely low-frequency human motion and complex electromagnetic environments.

[0004] To achieve the present invention, the technical solution adopted is as follows: An electromagnetic-piezoelectric differential energy harvesting device based on magnetostriction, integrated into a wearable device or connected to the human body, is characterized by comprising a first stator layer, a second rotor layer, and a third stator layer arranged sequentially from top to bottom. The second rotor layer is provided with at least one axially magnetized permanent magnet. Multiple composite energy harvesting units are symmetrically arranged on opposite surfaces of the first stator layer and the third stator layer. Each composite energy harvesting unit includes a magnetostrictive rod fixed at one end and a piezoelectric thin film attached to its surface along the axial direction of the magnetostrictive rod. The composite energy harvesting unit located on the first stator layer and its corresponding composite energy harvesting unit on the third stator layer are differentially connected in series.

[0005] When the human body moves, the second rotor layer rotates accordingly, and the permanent magnets on the second rotor layer also generate dynamic magnetic field changes, causing microscopic axial strain in the magnetostrictive rod. This strain drives the piezoelectric film attached to the magnetostrictive rod to deform, thereby generating a high-voltage electrical signal. Furthermore, as the turntable rotates, because the magnetic poles at both ends of the permanent magnets on the turntable are opposite, the symmetrically arranged composite energy harvesting units simultaneously sense magnetic signals with completely opposite polarities, generating a 180° phase difference. Through a differential series circuit, the two sets of signals are superimposed, thereby amplifying the output voltage and achieving multiplied energy harvesting in a wearable environment. Simultaneously, when the harvesting device is subjected to external stray magnetic fields or interference signals from the internal drive motor, the common-mode rejection characteristics of the differential connection cancel out the noise signals in the series circuit, ensuring the purity and stability of the output voltage.

[0006] In a preferred embodiment, the composite energy harvesting unit further includes an electromagnetic induction component, which is an induction coil at least partially sleeved outside the magnetostrictive rod. With this configuration, when the second rotor layer rotates due to human movement, the induction coil directly generates an induced current through magnetic flux switching. Furthermore, because the permanent magnets on the turntable have opposite magnetic poles at both ends, the induction coils of the symmetrically arranged composite energy harvesting units simultaneously sense magnetic signals of completely opposite polarities, generating a 180° phase difference. Through a differential series circuit, the two sets of signals are superimposed in polarity, achieving highly efficient multiplication of micro-energy harvesting in a wearable environment.

[0007] In a preferred embodiment, the permanent magnet and the magnetostrictive rod are arranged in parallel or collinear order. This arrangement maximizes magnetic flux utilization, thereby inducing the strongest axial strain in the magnetostrictive rod. Whether the permanent magnet and the magnetostrictive rod are parallel to the rotation axis of the second rotor layer is not limited.

[0008] In a preferred embodiment, the rotor further includes a rotating shaft, with the first stator layer and the third stator layer both fixedly connected to or integrally formed with the rotating shaft, and the second rotor layer rotatably fitted onto the rotating shaft; alternatively, the second rotor layer is fixedly connected to or integrally formed with the rotating shaft, and the rotating shaft is rotatably connected to the first stator layer and the third stator layer. With this configuration, when a human body moves, the second rotor layer rotates around the rotating shaft.

[0009] In a preferred embodiment, the system further includes a cylindrical outer shell, with the first stator layer and the third stator layer respectively disposed at both ends of the cylindrical outer shell. An annular track is provided on the inner wall of the cylindrical outer shell, and the second rotor layer is rotatably disposed within the annular track. With this configuration, when a human body moves, the second rotor layer rotates within the annular track.

[0010] In a preferred embodiment, the magnetostrictive rod is made of any of the following materials: iron-gallium alloy, iron-aluminum alloy, terbium-dysprosium-iron alloy, nickel-manganese-gallium alloy, and / or the piezoelectric film is made of any of the following materials: PVDF polyvinylidene fluoride, PVDF-TrFE polyvinylidene fluoride copolymer, PLA biopolymer, PDMS polydimethylsiloxane.

[0011] In a preferred embodiment, when the composite energy harvesting unit is disposed on the upper surface of the first stator layer / the third stator layer, the lower end of the magnetostrictive rod is fixed to the first stator layer / the third stator layer, and the upper end is a free end. When the composite energy harvesting unit is disposed on the lower surface of the first stator layer / the third stator layer, the upper end of the iron-gallium alloy magnetostrictive rod is fixed to the first stator layer / the third stator layer, and the lower end is a free end. With this configuration, one end of the magnetostrictive rod is fixed, and the other end is a free end. When the magnetostrictive rod generates microscopic axial strain, it can cause the piezoelectric thin film attached to its surface to undergo axial change accordingly.

[0012] In a preferred embodiment, the piezoelectric film is sleeved on the surface of the magnetostrictive rod. This arrangement results in more uniform force distribution on the piezoelectric film compared to when it is axially attached to the surface of the magnetostrictive rod, and better synchronization with the axial changes of the magnetostrictive rod.

[0013] In a preferred embodiment, the second rotor layer is provided with a plurality of permanent magnets, which are arranged circumferentially or in a straight line, and adjacent permanent magnets are distributed in an alternating N-S pattern. This arrangement ensures that two adjacent permanent magnets form a complete closed magnetic loop path, maximizing the efficiency of cutting magnetic field lines.

[0014] Compared with the prior art, the present invention has the following advantages and beneficial effects: 1. By integrating two transducer components, magnetostrictive rod and piezoelectric film, into a sandwich-type stator-rotor structure, the coordinated capture of low-frequency high-power motion (electromagnetic path) and high-frequency micro-vibration (piezoelectric path) is cleverly achieved. 2. By constructing a closed magnetic circuit through a symmetrical layout and cooperating with differential series to perform phase reversal, the effective power generation signal is doubled and superimposed. At the same time, it has a natural anti-electromagnetic interference capability, and achieves high-quality acquisition of micro-energy in complex electromagnetic environments with high efficiency. Attached Figure Description

[0015] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic diagram of the overall exploded structure of the data acquisition device according to an embodiment of the present invention; Reference numerals: 1-magnetostrictive rod, 2-piezoelectric film, 3-induction coil, 4-permanent magnet, 5-first stator layer, 6-second rotor layer, 7-third stator layer. Detailed Implementation

[0016] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0017] Example Combination Figure 1 As shown, this invention provides an electromagnetic-piezoelectric differential energy harvesting device based on magnetostriction, comprising a first stator layer 5, a second rotor layer 6, and a third stator layer 7 arranged sequentially from top to bottom. The second rotor layer 6 is provided with a plurality of axially magnetized permanent magnets 4, which are arranged circumferentially or linearly, with adjacent permanent magnets 4 arranged in an alternating N-S pattern. The plurality of permanent magnets 4 can be arranged at equal intervals or non-equal intervals. A plurality of composite energy harvesting units are symmetrically arranged on the opposite surfaces of the first stator layer 5 and the third stator layer 7. Each composite energy harvesting unit includes a magnetostrictive rod 1 fixed at one end, a piezoelectric film 2 attached to its surface along the axial direction of the magnetostrictive rod 1, and an induction coil 3 at least partially sleeved outside the magnetostrictive rod 1. The composite energy harvesting unit on the first stator layer 5 and its corresponding composite energy harvesting unit on the third stator layer 7 are connected in differential series. The first stator layer 5 and the third stator layer 7 are made of high-permeability stainless steel or flexible PCB board. The magnetostrictive rod 1 and the permanent magnet 4 are arranged in parallel or collinear. The piezoelectric film 2 is sleeved on the surface of the magnetostrictive rod 1. The magnetostrictive rod 1 is made of any of the following materials: iron-gallium alloy, iron-aluminum alloy, terbium-dysprosium-iron alloy, and nickel-manganese-gallium alloy. The piezoelectric film 2 is made of any of the following materials: PVDF polyvinylidene fluoride, PVDF-TrFE polyvinylidene fluoride copolymer, PLA biopolymer, and PDMS polydimethylsiloxane. The induction coil 3 is an induction coil wound with ultra-fine enameled wire. In use, this device is integrated into a wearable device or connected to the human body. When the human body moves, driving the second rotor layer 6 to rotate relative to the first stator layer 5 and the third stator layer 7, the alternating magnetic field generated by the permanent magnet 4 causes the induction coil 3 to generate a low-frequency induced current through magnetic flux switching, capturing high-power kinetic energy. Simultaneously, the dynamic magnetic field causes the magnetostrictive rod 1 to produce axial periodic expansion and contraction strain. This strain directly drives the piezoelectric film 2, which is in close contact with its surface, to deform and generate charge. Because the magnetic poles of the permanent magnets 4 facing both ends of the second rotor layer 6 are completely opposite, the induced voltages generated by the composite energy-harvesting units at corresponding positions in the first stator layer 5 and the third stator layer 7 have a phase difference of 180° at the same instant. Through the differential series connection logic, phase reversal is used to superimpose the signals in terms of polarity, multiplying the total output voltage, and utilizing common-mode rejection characteristics to automatically cancel out stray magnetic fields from the environment or interference signals from the drive motor in the same direction.

Claims

1. A magnetostrictive electromagnetic-piezoelectric differential energy harvesting device, integrated into a wearable device or connected to the human body, characterized in that, The system includes a first stator layer (5), a second rotor layer (6), and a third stator layer (7) arranged sequentially from top to bottom. The second rotor layer (6) is provided with at least one axially magnetized permanent magnet (4). Multiple composite energy harvesting units are symmetrically arranged on the opposite surfaces of the first stator layer (5) and the third stator layer (7). Each composite energy harvesting unit includes a magnetostrictive rod (1) fixed at one end and a piezoelectric film (2) attached to its surface along the axial direction of the magnetostrictive rod (1). The composite energy harvesting unit located on the first stator layer (5) and its corresponding composite energy harvesting unit on the third stator layer (7) are connected in differential series.

2. The electromagnetic-piezoelectric differential energy harvesting device based on magnetostriction according to claim 1, characterized in that, The composite energy harvesting unit also includes an induction coil (3), which is at least partially sleeved outside the magnetostrictive rod (1).

3. The electromagnetic-piezoelectric differential energy harvesting device based on magnetostriction according to claim 1, characterized in that, The permanent magnet (4) and the magnetostrictive rod (1) are arranged in parallel or collinear order.

4. The electromagnetic-piezoelectric differential energy harvesting device based on magnetostriction according to claim 1, characterized in that, It also includes a rotating shaft, wherein the first stator layer (5) and the third stator layer (7) are fixedly connected to or integrated with the rotating shaft, and the second rotor layer (6) is rotatably sleeved on the rotating shaft; or, the second rotor layer (6) is fixedly connected to or integrated with the rotating shaft, and the rotating shaft is rotatably connected to the first stator layer (5) and the third stator layer (7).

5. The electromagnetic-piezoelectric differential energy harvesting device based on magnetostriction according to claim 1, characterized in that, It also includes a cylindrical outer shell, the first stator layer (5) and the third stator layer (7) are respectively disposed at both ends of the cylindrical outer shell, the inner wall of the cylindrical outer shell is provided with an annular track, and the second rotor layer (6) is rotatably disposed in the annular track.

6. The electromagnetic-piezoelectric differential energy harvesting device based on magnetostriction according to claim 1, characterized in that, The magnetostrictive rod (1) is made of any of the following materials: iron-gallium alloy, iron-aluminum alloy, terbium-dysprosium-iron alloy, nickel-manganese-gallium alloy, and / or the piezoelectric film (2) is made of any of the following materials: PVDF polyvinylidene fluoride, PVDF-TrFE polyvinylidene fluoride copolymer, PLA biopolymer, PDMS polydimethylsiloxane.

7. The electromagnetic-piezoelectric differential energy harvesting device based on magnetostriction according to claim 1, characterized in that, When the composite energy harvesting unit is disposed on the upper surface of the first stator layer (5) / the third stator layer (7), the lower end of the magnetostrictive rod (1) is fixed to the first stator layer (5) / the third stator layer (7), and the upper end is a free end. When the composite energy harvesting unit is disposed on the lower surface of the first stator layer (5) / the third stator layer (7), the upper end of the iron-gallium alloy magnetostrictive rod (1) is fixed to the first stator layer (5) / the third stator layer (7), and the lower end is a free end.

8. The electromagnetic-piezoelectric differential energy harvesting device based on magnetostriction according to claim 1, characterized in that, The piezoelectric film (2) is sleeved on the surface of the magnetostrictive rod (1).

9. The electromagnetic-piezoelectric differential energy harvesting device based on magnetostriction according to claim 1, characterized in that, The second rotor layer (6) is provided with a plurality of permanent magnets (4), which are arranged in a circumferential or straight line, and adjacent permanent magnets (4) are distributed in an alternating N-S pattern.

10. The electromagnetic-piezoelectric differential energy harvesting device based on magnetostriction according to claim 9, characterized in that, Multiple permanent magnets (4) are arranged at equal intervals.

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