A piezoelectric-electromagnetic composite vibration power generation device with a magnetic circuit switch type cantilever beam structure

Abstract

The application relates to the field of energy collection, in particular to a magnetic circuit switch type cantilever beam structure piezoelectric-electromagnetic composite vibration power generation device, which comprises a base, a bottom plate, a support, a permanent magnet, a fixing frame, a cantilever beam, a piezoelectric sheet, a weight, a coil column and a coil. The base is provided with a groove, the bottom plate is fixed in the groove, the support is fixed on the base, the permanent magnet penetrates through the support, the fixed end of the cantilever beam is fixed on the top of the support through the fixing frame, the permanent magnet is connected with the bottom plate and the cantilever beam, the piezoelectric sheet is arranged near the fixed end of the cantilever beam, the weight is fixed near the free end of the cantilever beam, the coil column is vertically fixed on the bottom plate, the coil surrounds the coil column, and the cantilever beam, the bottom plate and the coil column are all made of soft magnetic material. The main body of the device is made of soft magnetic material, the on-off of the magnetic circuit is realized through the up-down oscillation of the cantilever beam, the piezoelectric sheet power generation and the electromagnetic induction power generation are combined, the power generation efficiency of the device is improved, and the device has a good application prospect in the field of vibration energy collection.

Description

Technical Field

[0001] This invention relates to the field of energy harvesting, specifically to a magnetic circuit switch type cantilever beam structure piezoelectric-electromagnetic composite vibration power generation device. Background Technology

[0002] With the rapid development of the Internet of Things (IoT) era, wireless sensor networks and low-power electronic devices have been widely used. Traditionally, there are two main ways to power these devices: batteries and external power cords. Using batteries significantly increases the maintenance costs of these devices, especially for multi-node wireless sensor networks; external power cords are prone to line failures and other problems, further limiting the movement of sensor nodes and greatly reducing their effectiveness. Therefore, environmental energy harvesting plays a crucial role in the IoT era, providing a continuous and stable energy output for nodes in different environments.

[0003] In industrial production, large equipment generates significant vibration energy during operation. Vibration energy harvesting devices collect this energy and use it to power sensor nodes in critical equipment components, enabling real-time monitoring of their operational status and improving equipment safety and production efficiency. These applications are particularly important in harsh environments such as coal mines, where they effectively power sensors, processing circuits, and wireless transmission circuits, thus preventing issues related to manual maintenance and line faults.

[0004] Existing piezoelectric-electromagnetic hybrid vibration power generation devices based on cantilever beam structure all work by using the vibration of the cantilever beam to induce a voltage by achieving relative displacement between the coil and the magnet. The drawback of this method is the low efficiency of electromagnetic power generation, while relying primarily on piezoelectric power generation cannot generate sufficient energy for electricity supply. Summary of the Invention

[0005] To address the above problems and improve electromagnetic power generation efficiency, this invention provides a magnetic circuit switch type cantilever beam structure piezoelectric-electromagnetic composite vibration power generation device, comprising: a base, a base plate, a support, a permanent magnet, a fixing frame, a cantilever beam, a piezoelectric sheet, a weight, a coil column, and a coil; the base has a groove, the base plate is fixed in the groove, the support is fixed on the base, the permanent magnet passes through the support, the fixed end of the cantilever beam is fixed to the top of the support through the fixing frame, the permanent magnet connects the base plate and the cantilever beam, the piezoelectric sheet is placed near the fixed end of the cantilever beam, the weight is fixed near the free end of the cantilever beam, the coil column is vertically fixed on the base plate, and the coil surrounds the coil column; the cantilever beam, the base plate, and the coil column are all made of soft magnetic material.

[0006] Furthermore, the direction of the base plate is parallel to the direction of the cantilever beam.

[0007] Furthermore, the length of the base plate is less than the length of the cantilever beam.

[0008] Furthermore, a screw hole is provided along the upper edge of the base plate, and the coil post is placed inside the screw hole.

[0009] Furthermore, there are five screw holes, distributed along the length of the base plate.

[0010] Furthermore, the coil post does not come into contact with the piezoelectric element.

[0011] Furthermore, the piezoelectric sheet includes a first piezoelectric sheet and a second piezoelectric sheet, with the first piezoelectric sheet disposed on the upper surface of the cantilever beam and the second piezoelectric sheet disposed on the lower surface of the cantilever beam.

[0012] Furthermore, the base, bracket, and fixing frame are all made of non-ferromagnetic materials.

[0013] Furthermore, at the contact point between the permanent magnet and the base plate, the area of ​​the base plate is larger than the area of ​​the permanent magnet.

[0014] Furthermore, at the contact point between the permanent magnet and the cantilever beam, the area of ​​the cantilever beam is larger than the area of ​​the permanent magnet.

[0015] The beneficial effects of this invention are as follows: This invention provides a magnetic circuit switch-type cantilever beam structure piezoelectric-electromagnetic composite vibration power generation device, comprising: a base, a base plate, a support, a permanent magnet, a fixing frame, a cantilever beam, a piezoelectric sheet, a weight, a coil column, and a coil. The base has a groove, the base plate is fixed within the groove, the support is fixed to the base, the permanent magnet passes through the support, the fixed end of the cantilever beam is fixed to the top of the support via the fixing frame, the permanent magnet connects the base plate and the cantilever beam, the piezoelectric sheet is positioned near the fixed end of the cantilever beam, the weight is fixed near the free end of the cantilever beam, the coil column is vertically fixed to the base plate, and the coil surrounds the coil column. The cantilever beam, base plate, and coil column are all made of soft magnetic material. In this invention, in addition to the piezoelectric sheet generating electricity, the permanent magnet, cantilever beam, base plate, and coil column constitute a magnetic circuit. The vibration of the cantilever beam controls the opening and closing of this magnetic circuit, resulting in a large change in magnetic flux in the coil, generating an induced electromotive force or induced current in the coil. This invention effectively combines piezoelectric power generation and electromagnetic induction power generation, improving the device's power generation efficiency, capturing more vibration energy from the surrounding environment, and significantly enhancing its vibration reduction effect. Traditional electromagnetic power generation devices generally have low peak voltages because, regardless of whether it's a suspension structure, spring structure, or traditional beam structure, the magnetic flux in the coil changes gradually. However, the magnetic circuit switch-type power generation structure in this invention allows for a dramatic change in magnetic flux at the moment the cantilever beam contacts and separates from the coil column, resulting in a larger output peak voltage and peak power. In summary, this invention's device can output energy within a certain frequency band. Compared to other electromagnetic power generation devices, the magnetic circuit switch-type power generation device in this invention has a higher peak voltage and peak power, showing promising application prospects in the field of vibration energy harvesting.

[0016] The present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a magnetic circuit switch type cantilever beam structure piezoelectric-electromagnetic composite vibration power generation device.

[0018] Figure 2 This is a three-dimensional assembly drawing of a magnetic circuit switch type cantilever beam structure piezoelectric-electromagnetic composite vibration power generation device.

[0019] Figure 3 This is a schematic diagram of the magnetic circuit in this invention.

[0020] Figure 4 This is a schematic diagram of the structure of the present invention after the casing is added.

[0021] In the diagram: 1. Base; 2. Base plate; 3. Bracket; 4. Permanent magnet; 5. Fastening screw; 6. Fixing frame; 7. Cantilever beam; 81. First piezoelectric element; 82. Second piezoelectric element; 9. Weight; 10. Coil column; 11. Coil. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided with reference to the accompanying drawings and embodiments.

[0023] Example 1

[0024] This invention provides a magnetic circuit switch type cantilever beam structure piezoelectric-electromagnetic composite vibration power generation device, such as... Figure 1 and Figure 2As shown, the system includes a base 1, a base plate 2, a bracket 3, a permanent magnet 4, a fixing frame 6, a cantilever beam 7, a piezoelectric sheet, a weight 9, a coil post 10, and a coil 11. The base 1 is made of non-ferromagnetic material, specifically plexiglass. A groove is provided on the base 1, and the base plate 2 is fixed within the groove. The base plate 1 is made of soft magnetic material to facilitate the conduction of magnetic field lines. The bracket 3 is fixed to the base 1. The width of the base plate 2 is greater than 1 cm and less than 1.5 cm. The bracket 3 is also made of non-ferromagnetic material, specifically plexiglass. The permanent magnet 4 penetrates the bracket 3, and the height of the permanent magnet 4 is the same as that of the bracket 3. This means that the bracket 3 covers the permanent magnet 4, thus supporting the cantilever beam 7 and preventing the cantilever beam 7 from directly and intensely compressing the permanent magnet 4, thus protecting the permanent magnet 4. The cantilever beam 7 is made of soft magnetic material. The fixed end of the cantilever beam 7 is fixed to the top of the bracket 3 via the fixing frame 6. The mounting bracket 6 is made of non-ferromagnetic material, specifically plexiglass. The permanent magnet 4 connects the base plate 1 and the cantilever beam 7. At the contact point between the permanent magnet 4 and the base plate 2, the area of ​​the base plate 2 is larger than the area of ​​the permanent magnet 4, allowing more magnetic field lines generated by the permanent magnet 4 to couple into the base plate 2. When the cantilever beam 7 contacts / disconnects from the coil post 10, the magnetic flux in the circuit changes more significantly, resulting in a stronger induced electromotive force in the coil 11. At the contact point between the permanent magnet 4 and the cantilever beam 7, the area of ​​the cantilever beam 7 is larger than the area of ​​the permanent magnet 4, allowing more magnetic field lines generated by the permanent magnet 4 to couple into the cantilever beam 7. When the cantilever beam 7 contacts / disconnects from the coil post 10, the magnetic flux in the circuit changes more significantly, resulting in a stronger induced electromotive force in the coil 11. A piezoelectric element is positioned near the fixed end of the cantilever beam 7. The piezoelectric element includes a first piezoelectric element 81 and a second piezoelectric element 82. The first piezoelectric element 81 is disposed on the upper surface of the cantilever beam 7, and the second piezoelectric element 82 is disposed on the lower surface of the cantilever beam 7. The electrodes of the first piezoelectric element 81 and the second piezoelectric element 82 are attached in opposite directions. Specifically, conductive silver paste is used to attach the first piezoelectric element 81 and the second piezoelectric element 82 to the upper and lower surfaces of the cantilever beam 7. Two twisted pairs of 0.15mm diameter enameled copper wires are connected from the surfaces of the first piezoelectric element 81 and the second piezoelectric element 82 through conductive silver paste for external power supply. A weight 9 is fixed near the free end of the cantilever beam 7, and the weight 9 is made of plexiglass. The coil post 10 is made of soft magnetic material. The coil post 10 is vertically fixed on the base plate 2, and the coil 11 surrounds the coil post 10, that is, the coil 11 is sleeved on the coil post 10. Two twisted pairs of 0.15mm diameter enameled copper wires are soldered from the coil 11 for external power supply. The base plate 2 is parallel to the direction of the cantilever beam 7, and the length of the base plate 2 is less than the length of the cantilever beam 7. When the cantilever beam 7 vibrates, it can contact the top of the coil column 10. When the cantilever beam 7 vibrates, the coil column 10 does not contact the piezoelectric element to prevent damage to the piezoelectric element and to avoid generating a small induced electromotive force.In this invention, the base plate 2, coil column 10, and cantilever beam 7 are made of soft magnetic material, which has a good magnetic conductivity and forms a magnetic circuit with the permanent magnet when vibrating.

[0025] The purpose of this invention is to improve the power generation performance of a vibration energy harvesting device by utilizing the up-and-down vibration of a cantilever beam 7 to achieve the switching on and off of the magnetic circuit. When the magnetic circuit is on, the magnetic field generated by the permanent magnet 4 is mostly confined within the magnetic circuit composed of soft magnetic material, resulting in a relatively high magnetic flux in the coil 11 within the magnetic circuit. When the magnetic circuit is off, the confining effect of the soft magnetic material on the magnetic field weakens drastically, and the magnetic flux in the coil 11 decreases rapidly. The vibration of the cantilever beam 7 creates a large rate of change in magnetic flux within the coil 11, thereby inducing a higher voltage in the coil. Simultaneously, the vibration of the cantilever beam 7 causes the piezoelectric sheet attached to it to deform, generating an induced voltage on the piezoelectric sheet. These two effects improve the power generation performance of the vibration energy harvesting device.

[0026] In this invention, in addition to the piezoelectric element generating electricity, such as Figure 3 As shown, the permanent magnet 4, cantilever beam 7, base plate 2, and coil column 10 constitute a magnetic circuit. The vibration of the cantilever beam 7 controls the opening and closing of this magnetic circuit, resulting in a large change in magnetic flux in the coil 11, generating an induced electromotive force or induced current in the coil 11. This invention fully combines piezoelectric power generation and electromagnetic induction power generation, improving the power generation efficiency of the device, capturing more vibration energy from the surrounding environment, and further enhancing the vibration reduction effect of the device. Traditional electromagnetic power generation devices generally have low peak voltages because, regardless of whether it is a suspension structure, spring structure, or traditional beam structure, the magnetic flux in the coil changes gradually. However, the magnetic circuit switch-type power generation structure in this invention allows the magnetic flux to change drastically at the moment of contact and separation between the cantilever beam 7 and the coil column 10, thereby obtaining a larger output peak voltage and peak power. In summary, the device of this invention can output energy within a certain frequency band. Compared with other electromagnetic power generation devices, the magnetic circuit switch-type power generation device of this invention can have a larger peak voltage and peak power, and has good application prospects in the field of vibration energy harvesting.

[0027] In practical applications, a casing is installed on the outside of the entire power generation device. The casing is made of transparent acrylic material, and the casing is fixed to the base 1 with screws. Figure 4 As shown.

[0028] Example 2

[0029] Based on Embodiment 1, the base plate 2 has screw holes along its upper edge, and the coil post 10 is disposed within these screw holes. There are five screw holes, distributed along the length of the base plate 2. The bottom end of the coil post 10 is threaded and fixed within the screw holes. In application, the coil post 10 can be disposed within different screw holes, thereby selecting the optimal operating frequency band and power generation efficiency.

[0030] Example 3

[0031] Based on embodiment 2, the base 1, bracket 3, and fixing frame 6 are provided with two through holes. The base 1, bracket 3, and fixing frame 6 are fixed together by two bolts and two fastening screws, so that the permanent magnet 4, cantilever beam 7 and base plate 2 can be in stable contact.

[0032] Example 4

[0033] Based on Example 3, the first piezoelectric element 81 and the second piezoelectric element 82 are made of ceramic, with a layer of silver plated on their upper and lower surfaces as electrodes. The lengths of the first piezoelectric element 81 and the second piezoelectric element 82 are 3.8 cm. The first piezoelectric element 81 and the second piezoelectric element 82 are attached to the cantilever beam 7 with opposite electrodes using conductive silver paste. A wire is led out from the other electrode to obtain the series voltage of the first piezoelectric element 81 and the second piezoelectric element 82.

[0034] Example 5

[0035] Based on embodiment 4, the top surface of the coil post 10 is a protruding hemispherical shape, and correspondingly, the lower surface of the cantilever beam 7 is provided with a hemispherical groove. On the one hand, this reduces the contact time between the cantilever beam 7 and the coil post 10, thereby increasing the change in magnetic flux in the coil 11 and improving the effective value of the induced electromotive force in the coil 11.

[0036] Furthermore, extensive experiments have shown that the optimal distance between the cantilever beam 7 and the coil post 10 is 1 mm. If the distance is too short, the cantilever beam 7 will not reach its maximum amplitude during vibration due to the obstruction of the coil post 10, resulting in poor power generation of the first piezoelectric element 81 and the second piezoelectric element 82; if the distance is too long, the cantilever beam 7 will not be able to contact the coil post 10 during vibration, resulting in poor electromagnetic power generation.

[0037] Furthermore, coil 11 should be fixed above coil post 10, near the point where cantilever beam 7 contacts coil post 10. This is because the change in magnetic flux is greatest at this location during the vibration of cantilever beam 7.

[0038] Furthermore, the cantilever beam 7 is wider at the contact point with the coil column 10, but narrower elsewhere, in order to enhance the coupling between the cantilever beam 7 and the coil column 10, facilitating the entry of magnetic field lines from the cantilever beam 7 into the coil column 10, further altering the magnetic flux in the coil 11, and ultimately generating a stronger induced electromotive force in the coil 11.

[0039] Furthermore, the cantilever beam 7 is provided with through holes. When the cantilever beam 7 vibrates, the top end of the coil column 10 can pass through the cantilever beam 7, and the contact range between the coil column 10 and the cantilever beam 7 is larger, which is suitable for applications with large vibration amplitude and can convert large vibration energy into electrical energy.

[0040] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A piezoelectric-electromagnetic composite vibration power generation device with a magnetic circuit switch type cantilever beam structure, characterized in that, include: The components include a base, a base plate, a bracket, a permanent magnet, a fixing frame, a cantilever beam, a piezoelectric sheet, a weight, a coil post, and a coil; the base has a groove. The base plate is fixed in the groove, the bracket is fixed on the base, the permanent magnet passes through the bracket, the fixed end of the cantilever beam is fixed to the top of the bracket through the fixing frame, the permanent magnet connects the base plate and the cantilever beam, the direction of the base plate is parallel to the direction of the cantilever beam, the length of the base plate is less than the length of the cantilever beam, the piezoelectric sheet is disposed near the fixed end of the cantilever beam, the weight is fixed near the free end of the cantilever beam, the coil column is vertically fixed on the base plate, the top surface of the coil column is a protruding hemispherical shape, correspondingly, the lower surface of the cantilever beam is provided with a hemispherical groove, the coil surrounds the coil column, the cantilever beam, the base plate, and the coil column are all made of soft magnetic material, the cantilever beam is provided with a through hole, when the cantilever beam vibrates, the top end of the coil column can pass through the cantilever beam, and the cantilever beam contacts the top end of the coil column; The base plate has a screw hole along its upper edge, and the coil post is disposed in the screw hole; there are five screw holes, and the five screw holes are distributed along the length of the base plate.

2. The magnetic circuit switch type cantilever beam structure piezoelectric-electromagnetic composite vibration power generation device as described in claim 1, characterized in that: The coil post does not contact the piezoelectric element.

3. The magnetic circuit switch type cantilever beam structure piezoelectric-electromagnetic composite vibration power generation device as described in claim 1, characterized in that: The piezoelectric element includes a first piezoelectric element and a second piezoelectric element, wherein the first piezoelectric element is disposed on the upper surface of the cantilever beam. The second piezoelectric element is disposed on the lower surface of the cantilever beam.

4. The magnetic circuit switch type cantilever beam structure piezoelectric-electromagnetic composite vibration power generation device as described in claim 1, characterized in that: The base, the bracket, and the fixing frame are all made of non-ferromagnetic materials.

5. The magnetic circuit switch type cantilever beam structure piezoelectric-electromagnetic composite vibration power generation device as described in claim 1, characterized in that: At the contact point between the permanent magnet and the base plate, the area of ​​the base plate is larger than the area of ​​the permanent magnet.

6. The magnetic circuit switch type cantilever beam structure piezoelectric-electromagnetic composite vibration power generation device as described in claim 1, characterized in that: At the contact point between the permanent magnet and the cantilever beam, the area of ​​the cantilever beam is larger than the area of ​​the permanent magnet.

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