Four-arm symmetrical structure electric-magnetic-mechanical energy combined acquisition device and method suitable for non-intrusive voltage sensor

Abstract

The invention discloses a four-arm symmetrical structure electric-magnetic-mechanical energy combined acquisition device and method suitable for a non-intrusive voltage sensor, and belongs to the technical field of multi-source energy acquisition. The device is composed of a base, a fixed restraining rod and four piezoelectric cantilever beams, the four cantilever beams are distributed in the X-axis direction and the Y-axis direction respectively, a four-arm symmetrical structure is formed, and electromagnetic disturbance signals in multiple directions can be responded at the same time. The cantilever beam comprises a magnetic-mechanical-electric coupling energy-taking cantilever beam and an electric-mechanical-electric coupling energy-taking cantilever beam which are respectively integrated with a magnetostrictive material and a dielectric elastomer, and are superposed with a piezoelectric crystal and a spring steel sheet, so that external electric field or magnetic field energy is converted into mechanical energy through a magnetostrictive or electrostrictive effect; and the piezoelectric crystal converts the electric energy into electric energy for output. The device is compact in structure and sensitive in response, can efficiently collect stray electromagnetic field and environment vibration energy in a power system, and provides stable self-powered support for a non-intrusive electric field sensor.

Description

Technical Field

[0001] This invention relates to the field of self-powered voltage sensor technology, and in particular to a four-arm symmetrical structure electro-magnetic-mechanical energy acquisition device and method suitable for non-invasive voltage sensors. Background Technology

[0002] With the rapid development of the Internet of Things (IoT), smart grids, and micro-sensing systems, an increasing number of distributed electronic devices are being deployed in urban, industrial, and power infrastructure. These devices place continuous and efficient demands on energy during operation; however, the limited lifespan and maintenance difficulties of traditional chemical batteries restrict the long-term reliability of these systems and pose environmental pollution problems. Therefore, energy harvesting technology, which directly extracts energy from the environment, has become an important development direction for realizing green, self-sufficient systems, especially in unattended or power-replacement-difficult scenarios, where its application value is increasingly prominent.

[0003] In power systems, non-invasive voltage sensors are of significant value because they can monitor electric fields without contact with electrical equipment. However, these sensors often require a stable and continuous power supply, and traditional battery power supply methods cannot meet their long-term operational needs and increase the complexity of equipment maintenance. Therefore, the development of self-powered non-invasive voltage sensors has become an urgent need.

[0004] Currently, most common energy harvesting devices are based on a single mechanism such as piezoelectricity, thermoelectricity, photovoltaics, or magnetostriction. However, due to the diversity, random direction, and intensity fluctuations of environmental energy sources, single energy harvesting technologies often have limitations in terms of conversion efficiency, stability, and output power, making it difficult to meet the high-efficiency power supply requirements of practical applications. Especially in power system environments, alternating low-frequency electromagnetic fields and structural mechanical vibrations often coexist, providing a unique resource background for multi-source collaborative energy harvesting.

[0005] In recent years, magneto-mechanical-electric (MME) energy harvesters based on magnetostrictive-piezoelectric coupling mechanisms have attracted widespread attention due to their compact structure and high output power. However, most existing MME energy harvesters rely on high-intensity magnetic fields or unidirectional magnetic excitation, making it difficult to adapt to complex energy distributions. Meanwhile, dielectric elastomers, due to their excellent electrostrictive properties, can undergo large deformations under electric field excitation, forming an electro-mechanical-electric (EME) energy conversion pathway when combined with piezoelectric elements. Integrating and synergistically working the magnetostrictive and electrostrictive mechanisms could potentially improve the response to stray electric and magnetic fields, enabling multi-source and efficient energy conversion. Summary of the Invention

[0006] To address the above shortcomings, this invention provides a four-arm symmetrical electromagnetic-mechanical energy structure suitable for non-invasive voltage sensors. The combined energy acquisition device and method can solve the problems of insufficient and inefficient energy acquisition through a multi-source energy acquisition mechanism, providing a reliable energy source for low-power devices such as non-invasive voltage sensors. The specific technical solution is as follows: A four-arm symmetrical structure electro-magnetic-mechanical energy acquisition device suitable for non-invasive voltage sensors includes a base, a fixed constraint rod, and a piezoelectric cantilever arm; The fixed constraint rod is located at the center of the base; the piezoelectric cantilever arm includes two sets of magneto-electro-electric coupled energy harvesting cantilever beams and two sets of electro-electro-electric coupled energy harvesting cantilever beams. Two sets of the magneto-mechanical-electric coupled energy harvesting cantilever beams are fixed on the base, and the two sets of magneto-mechanical-electric coupled energy harvesting cantilever beams are set at right angles. One set of magneto-mechanical-electric coupled energy harvesting cantilever beams is defined as the positive X-axis, and the other set of magneto-mechanical-electric coupled energy harvesting cantilever beams is defined as the positive Y-axis. One set of the electro-mechanical-electric coupling energy harvesting cantilever beams is fixed to the base in the X-axis negative direction, and the other set of the electro-mechanical-electric coupling energy harvesting cantilever beams is fixed to the base in the Y-axis negative direction; Both the magneto-mechanical-electric coupled energy harvesting cantilever beam and the electro-mechanical coupled energy harvesting cantilever beam have mass blocks at their ends.

[0007] Preferably, the magneto-mechanical-electric coupling energy harvesting cantilever beam is composed of a first piezoelectric crystal, a magnetostrictive material layer, and a first spring steel sheet stacked sequentially from top to bottom.

[0008] Preferably, the mass block at the end of the magneto-mechanical-electric coupling energy harvesting cantilever beam is a permanent magnet mass block.

[0009] Preferably, the electro-mechanical-electric coupling energy harvesting cantilever beam is composed of a second piezoelectric crystal, a dielectric elastomer layer, and a second spring steel sheet layer stacked sequentially from top to bottom.

[0010] Preferably, the first or second piezoelectric crystal adopts a comb-shaped electrode configuration, with positive and negative electrodes alternately arranged on the piezoelectric crystal in a comb-like pattern.

[0011] Preferably, the first piezoelectric crystal or the second piezoelectric crystal is adopted. d 33 Work mode.

[0012] Preferably, the mass block is detachably connected to the end of the magneto-mechanical-electrical coupled energy harvesting cantilever beam and the electro-mechanical-electrical coupled energy harvesting cantilever beam.

[0013] Preferably, the magnetostrictive material layer is made of Terfenol-D, and the first piezoelectric crystal is made of PZT material.

[0014] A method for combined electro-magnetic-mechanical energy acquisition based on the above-mentioned device includes the following steps: Magnetostrictive materials in magneto-mechanical-electric coupled energy harvesting cantilever beams convert stray magnetic field energy into mechanical energy of the energy harvesting system based on the magnetostrictive effect. The dielectric elastomer material in the electromechanical coupled energy harvesting cantilever beam converts stray electric field energy into mechanical energy of the energy harvesting system based on the electrostriction effect. The cantilever beam also directly harvests mechanical energy from environmental vibrations. The mechanical energy of the energy harvesting system is ultimately converted into electrical energy output through piezoelectric crystals to power distributed electronic devices.

[0015] Compared with the prior art, the beneficial effects of the present invention are: This invention efficiently harvests energy from stray electromagnetic fields and low-frequency environmental vibrations. The four-arm symmetrical structure design allows the device to respond omnidirectionally to electromagnetic fields and environmental vibrations from different directions, significantly improving the system's energy harvesting efficiency. In particular, by optimizing the device's structural dimensions, this invention enables it to achieve second-order resonance with the electromagnetic field, thereby further enhancing energy conversion efficiency and output power. This device not only efficiently provides stable self-power for low-power devices such as non-invasive voltage sensors but also possesses excellent adaptability, enabling stable operation in complex power system environments. By achieving coordinated harvesting of multi-source energy, this invention has broad application prospects, particularly suitable for electric field monitoring in power systems, smart grid equipment, and other distributed sensor systems requiring long-term self-powering. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0017] Figure 1 A schematic diagram of a multi-source energy harvesting device with a four-arm symmetrical structure; Figure 2 Schematic diagram of a magneto-mechanical-electric coupling energy harvesting cantilever beam structure; Figure 3 Schematic diagram of an electro-mechanical coupling energy harvesting cantilever beam structure; Figure 4 This is a diagram of a dual piezoelectric crystal structure and its piezoelectric mode; Figure 5 The dynamic frequency response characteristic of the output voltage of a multi-source energy harvesting device with a four-arm symmetrical structure; Figure 6 The diagrams show the first and second modes of the cantilever beam. Figure 7 A schematic diagram of stress distribution in a multi-source energy harvesting device with a four-arm symmetrical structure; Figure 8 A schematic diagram of the potential of a multi-source energy harvesting device with a four-arm symmetrical structure; Figure 9 Potential, output power, and load characteristics of a multi-source energy harvesting device with a four-arm symmetrical structure; Reference numerals: 1-Piezoelectric cantilever beam; 2-Base; 3-Fixed constraint rod; 101-Magnetic-electro-electric coupling energy harvesting cantilever beam along the X-axis; 102-Magnetic-electro-electric coupling energy harvesting cantilever beam along the Y-axis; 103-Electro-electro-electric coupling energy harvesting cantilever beam along the X-axis; 104-Electro-electro-electric coupling energy harvesting cantilever beam along the Y-axis; 4-First piezoelectric crystal; 5-First spring steel sheet; 6-Magnetostrictive material layer; 7-Permanent magnet mass block; 8-Second piezoelectric crystal; 9-Dielectric elastomer layer; 10-Second spring steel sheet; 11-Mass block Detailed Implementation The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0018] In the description of this invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0019] In the description of this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. Where the terms "first," "second," and "third" are used for descriptive purposes and to distinguish technical features, they should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the sequential relationship of the indicated technical features.

[0020] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Furthermore, the technical features involved in the different embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0021] Example 1 Please see Figure 1-9 A schematic diagram of a four-arm symmetrical structure electro-magnetic-mechanical energy combined acquisition device proposed in this invention is shown below. Figure 1 As shown, it consists of four piezoelectric cantilever beams 1, a base 2, and fixed constraint rods 3. The four piezoelectric cantilever beams include a magneto-mechanical-electric (MME) coupled energy harvesting cantilever beam 101 along the X-axis, a magneto-mechanical-electric coupled energy harvesting cantilever beam 102 along the Y-axis, an electro-mechanical-electric (EME) coupled energy harvesting cantilever beam 103 along the X-axis, and an electro-mechanical-electric coupled energy harvesting cantilever beam 104 along the Y-axis. The base and fixed constraint rods of the energy harvesting device are both made of steel. All four piezoelectric cantilever beams are fixed to the base, and the fixed constraint rods are fixed to the center of the base, thus providing a fixed constraint for the base.

[0022] The structure of a magneto-mechanical-electric (MME) coupled energy harvesting cantilever beam is as follows: Figure 2As shown, the cantilever beam is composed of a first piezoelectric crystal 4, a first spring steel sheet 5, and a magnetostrictive material 6 stacked together. A permanent magnet mass block 7 is set at the end of the cantilever beam. The double-layer piezoelectric crystal PZT and the magnetostrictive material Terfenol-D are stacked on the spring steel sheet, with one end of the spring steel sheet fixed to the base and the other end connected to the permanent magnet mass block. The magneto-mechanical-electric coupling energy harvesting cantilever beam can be used to collect magnetic field energy from stray magnetic fields and mechanical energy from environmental vibrations. Based on the magnetostrictive effect, under the action of an external alternating magnetic field, the magnetostrictive material will undergo a small strain along its magnetization direction. This strain is converted into periodic bending deformation in the cantilever beam structure, forming the equivalent mechanical vibration of the cantilever beam. The magnetostrictive material converts stray magnetic field energy into the mechanical energy of the cantilever beam. At the same time, the cantilever beam can also harvest mechanical energy from environmental vibrations. When the cantilever beam undergoes bending vibration under magnetic field excitation and environmental vibration excitation, the piezoelectric crystal material on its surface synchronously generates strain. Based on the piezoelectric effect, this strain is converted into charge accumulation in the piezoelectric layer, forming an alternating current output. This realizes the energy transfer and conversion process from magnetic energy to mechanical energy and then to electrical energy, i.e., magneto-mechanical-electrical coupling energy harvesting. A permanent magnet mass block is installed at the end of the cantilever beam. On the one hand, the permanent magnet provides an external magnetic field source for the cantilever beam, improving energy harvesting efficiency. On the other hand, by adjusting the position and mass of the permanent magnet, frequency matching between the cantilever beam and the spatial magnetic field can be achieved, increasing the output power. This magneto-mechanical-electrical coupling energy harvesting method allows the device to simultaneously respond to external electric fields and environmental vibration energy, thereby broadening the energy harvesting range and significantly improving energy conversion efficiency.

[0023] Electromechanical (EME) coupled energy harvesting cantilever beam structures, such as Figure 3As shown, the cantilever beam is composed of a second piezoelectric crystal 8, a dielectric elastomer layer 9, and a second spring steel sheet 10 stacked together, with a mass block 11 at one end of the cantilever beam. The double-layer piezoelectric crystal PZT and the dielectric elastomer material (polyvinylidene fluoride, PVDF) are respectively stacked on both sides of the spring steel sheet. One end of the spring steel sheet is fixed to the base, and the other end is connected to the mass block. This electromechanical-electric coupling energy harvesting cantilever beam can collect energy from stray electric fields and environmental vibrations. Based on the electrostriction effect of the dielectric elastomer, when an external electric field acts on the dielectric elastomer, the material undergoes a small strain along the direction of the electric field. This strain is converted into periodic bending deformation through the spring steel sheet structure, forming the equivalent mechanical vibration of the cantilever beam. The dielectric elastomer material converts stray electric field energy into the mechanical energy of the cantilever beam. After superimposed with environmental vibration excitation, the cantilever beam achieves a composite mechanical response. Under the combined action of the external electric field and environmental vibration, the cantilever beam undergoes bending vibration, and the piezoelectric crystals on its surface synchronously generate strain. Based on the piezoelectric effect, this strain is converted into charge accumulation in the piezoelectric material, forming an alternating current output, thus realizing the energy conversion from electrical energy to mechanical energy and back to electrical energy, i.e., electromechanical-electrical energy harvesting. A mass block is installed at the end of the cantilever beam. The introduction of the mass block not only improves the structure's inertia and vibration response sensitivity, but also allows for matching with the external electric field and vibration frequency through mass and position adjustment. By rationally designing the dimensions of the cantilever beam, the configuration of the mass block, and the parameters of the piezoelectric crystal and dielectric elastomer materials, the system's output power and operational stability can be optimized. In this invention, the electromechanical-electrical energy harvesting method allows the device to simultaneously respond to external electric fields and environmental vibration energy, thereby broadening the energy harvesting range and significantly improving energy conversion efficiency.

[0024] Double piezoelectric crystal structure and its piezoelectric modes, such as Figure 4 As shown, to increase the output power of the energy harvesting device, PZT piezoelectric crystals are arranged on the side of the cantilever beam, and the piezoelectric crystals operate in the following mode: d 33 The operating mode, where the electric displacement direction of the piezoelectric crystal aligns with the direction of the stress it experiences, offers advantages such as high sensitivity and high efficiency, enabling efficient conversion of mechanical energy into electrical energy output even under low-frequency vibrations. Furthermore, the PZT piezoelectric crystal in this invention employs a comb-tooth electrode configuration, with positive and negative electrodes alternately arranged on the crystal. By adjusting the size, distance, and number of these comb-tooth electrodes, the electric field distribution of the piezoelectric crystal can be optimized, thereby improving energy conversion efficiency.

[0025] To increase the output power of the energy harvesting device, frequency matching between the energy harvesting system and the stray electromagnetic field is necessary. The stray electromagnetic field frequency is typically 50 / 60Hz. Existing energy harvesting technologies often operate the cantilever beam device in the first-order bending mode. In this mode, increasing the mass of the cantilever beam end mass block can increase the output voltage of the cantilever beam system, but it also lowers the system's resonant frequency, making resonance less likely. Therefore, this invention optimizes the structural dimensions of the energy harvesting device to enable the energy harvesting system to resonate with the environmental stray electromagnetic field in the second-order bending mode. Schematic diagrams of the first-order and second-order bending modes of the cantilever beam are shown below. Figure 5 As shown.

[0026] In this embodiment, the energy harvesting device was modeled and analyzed using the multiphysics analysis software COMSOL Multiphysics. The dynamic frequency response characteristics of the output voltage of the four-arm symmetrical multi-source energy harvesting device are as follows: Figure 7 As shown, the energy harvesting system exhibits first-order resonance when the stray electromagnetic field frequency is 12Hz, and second-order resonance when the stray electromagnetic field frequency is 60Hz. The energy harvesting device resonates second-orderly with the stray electromagnetic field.

[0027] When the electric field strength in space is 10 kV / m, the frequency is 60 Hz, and the direction is along the positive x-axis, and the magnetic field strength in space is 0.6 Oe, the frequency is 60 Hz, and the direction is along the positive y-axis, the stress distribution of the energy harvesting device is as follows: Figure 8 As shown, its potential distribution is as follows Figure 9 As shown, the maximum stress on the device is 6.02 × 10⁻⁶. 6 The voltage is N / m², and the maximum potential is 3.55V. The output power of the energy harvesting device is related to the external impedance. When the external load is 0-10 KΩ, the maximum output power of the energy harvesting device is 16.8mW, which is higher than most current energy harvesting devices.

[0028] Example 2 This embodiment discloses a method for joint acquisition of electro-magnetic-mechanical energy based on the above-mentioned device, including the following steps: Magnetostrictive materials in magneto-mechanical-electric coupled energy harvesting cantilever beams convert stray magnetic field energy into mechanical energy of the energy harvesting system based on the magnetostrictive effect. The dielectric elastomer material in the electromechanical coupled energy harvesting cantilever beam converts stray electric field energy into mechanical energy of the energy harvesting system based on the electrostriction effect. The cantilever beam also directly harvests mechanical energy from environmental vibrations. The mechanical energy of the energy harvesting system is ultimately converted into electrical energy output through piezoelectric crystals to power distributed electronic devices.

[0029] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A four-arm symmetric structure electro-magnetic-mechanical energy combined acquisition device suitable for non-invasive voltage sensor, characterized in that, The piezoelectric cantilever arm includes a base, a fixed constraint rod and a piezoelectric cantilever arm. The fixed constraint rod is arranged at the center of the base, and the piezoelectric cantilever arm includes two groups of magnetic-mechanical-electric coupling energy harvesting cantilever beams and two groups of electric-mechanical-electric coupling energy harvesting cantilever beams. The two groups of magnetic-mechanical-electric coupling energy harvesting cantilever beams are fixed on the base and arranged at right angles, and one group of the magnetic-mechanical-electric coupling energy harvesting cantilever beams is defined as an X positive axis, and the other group of the magnetic-mechanical-electric coupling energy harvesting cantilever beams is defined as a Y positive axis. One group of the electric-mechanical-electric coupling energy harvesting cantilever beams is fixed on the base in the direction of an X negative axis, and the other group of the electric-mechanical-electric coupling energy harvesting cantilever beams is fixed on the base in the direction of a Y negative axis. The magnetic-mechanical-electric coupling energy harvesting cantilever beams and the electric-mechanical-electric coupling energy harvesting cantilever beams are all provided with mass blocks at the ends.

2. The four-arm symmetric structure electro-magnetic-mechanical energy combined collection device suitable for non-invasive voltage sensor according to claim 1, characterized in that, The magnetic-mechanical-electric coupling energy harvesting cantilever beam is sequentially composed of a first piezoelectric crystal, a magnetostrictive material layer and a first spring steel sheet from top to bottom.

3. A four-arm symmetric structure electro-magnetic-mechanical energy combined harvesting device suitable for non-invasive voltage sensor according to claim 2, characterized in that, The mass block at the end of the magnetic-mechanical-electric coupling energy harvesting cantilever beam is a permanent magnet mass block.

4. The four-arm symmetric structure electro-magnetic-mechanical energy combined harvesting device suitable for non-invasive voltage sensor according to claim 1, characterized in that, The electric-mechanical-electric coupling energy harvesting cantilever beam is sequentially composed of a second piezoelectric crystal, a dielectric elastomer layer and a second spring steel sheet layer from top to bottom.

5. A four-arm symmetric structure electro-magnetic-mechanical energy combined harvesting device suitable for non-invasive voltage sensor according to claim 2 or 4, characterized in that, The first piezoelectric crystal or the second piezoelectric crystal adopts a comb-shaped electrode configuration, and the positive and negative electrode comb-shaped electrodes are alternately arranged on the piezoelectric crystal.

6. A four-arm symmetric structure electro-magnetic-mechanical energy combined harvesting device suitable for non-invasive voltage sensor according to claim 2 or 4, characterized in that, The first piezoelectric crystal or the second piezoelectric crystal employs d 33 Operating mode.

7. The four-arm symmetric structure electro-magnetic-mechanical energy combined harvesting device suitable for non-invasive voltage sensor according to claim 1, characterized in that, The mass block is detachably connected to the ends of the magnetic-mechanical-electric coupling energy harvesting cantilever beams and the electric-mechanical-electric coupling energy harvesting cantilever beams.

8. The four-arm symmetric structure electro-magnetic-mechanical energy combined harvesting device suitable for non-invasive voltage sensor according to claim 1, characterized in that, The material of the magnetostrictive material layer is Terfenol-D, and the first piezoelectric crystal is PZT material.

9. A method for the combined harvesting of electro-magnetic-mechanical energy based on the device according to any one of claims 1-8, characterized in that, The method includes the following steps: The magnetostrictive material in the magnetic-mechanical-electric coupling energy harvesting cantilever beam converts the stray magnetic field energy into mechanical energy of the energy harvesting system based on the magnetostrictive effect; The dielectric elastomer material in the electric-mechanical-electric coupling energy harvesting cantilever beam converts the stray electric field energy into mechanical energy of the energy harvesting system based on the electrostrictive effect; The cantilever beam also directly obtains mechanical energy from environmental vibration, and the mechanical energy of the energy harvesting system is finally converted into electric energy output through the piezoelectric crystal to supply power for distributed electronic devices.

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