Piezoelectric and electromagnetic combined type vibration energy collector

Abstract

The invention discloses a piezoelectric and electromagnetic combined type vibration energy collector, which comprises a fixed bracket, a shell, a motion conversion assembly, a piezoelectric transduction assembly and an electromagnetic transduction assembly, and is characterized in that the motion conversion assembly comprises a rotating shaft which is arranged on the shell and is vertical to the shell, a cam fixedly arranged on the rotating shaft, and a connecting rod and a sliding block which are rotationally connected with the cam; the piezoelectric transduction assembly comprises a piezoelectric cantilever beam fixed on the rotating shaft and a magnet mass block attached to the free end of the piezoelectric cantilever beam; the electromagnetic transduction assembly comprises a spring fixedly installed on the base, a coil and a movable magnet connected with the spring. In the process of converting vibration mechanical energy into electric energy, piezoelectric and electromagnetic transduction mechanisms are effectively combined to improve the energy conversion efficiency, and the collection efficiency is further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of vibration energy harvesting, and in particular to a piezoelectric and electromagnetic composite vibration energy harvester. Background Art

[0002] Microelectromechanical systems (MEMS) and integrated circuits are developing rapidly, driving electronic devices toward integration and low power consumption. Various miniaturized, low-power electronic devices, such as wireless sensor network nodes, wearable devices, and implantable medical devices, are gradually maturing. These devices are used in many applications, such as remote monitoring and human health monitoring. Traditional chemical battery-powered devices hinder the development of microelectronic devices. Energy harvesting technology, as a new energy storage device, has attracted widespread attention and is crucial for achieving sustainable energy supply.

[0003] The piezoelectric effect was discovered by the Curie brothers in the 1880s. In recent years, with advances in materials science, micromachining, and microelectronics, piezoelectric energy harvesting technology has rapidly developed. Piezoelectric materials exhibit a positive piezoelectric effect, generating an electric charge when subjected to mechanical stress. This can convert vibrational energy from the environment into electrical energy, resulting in a high energy density.

[0004] Electromagnetic vibration energy harvesting technology is based on Faraday's law of electromagnetic induction. When a part of the conductor in a closed circuit moves by cutting the magnetic lines of force, an electric current will be generated on the conductor, which can realize the mutual conversion of mechanical energy and electrical energy.

[0005] Most single-source energy harvesters can only effectively collect vibration energy in a single direction, with a very small bandwidth or large amplitude. Consequently, vibration energy harvesters typically have low output power. The magnetic flux leakage of electromagnetic energy harvesters limits their use in high-power applications. Piezoelectric energy harvesters made of materials like PZT are brittle and prone to fatigue and fracture under high-frequency cyclic loads, limiting their application. Composite vibration energy harvesters combine multiple energy conversion mechanisms, effectively combining the high voltage generated by piezoelectricity with the high current generated by electromagnetics, delivering higher power output and maintaining stability over long periods of operation. Summary of the Invention

[0006] The object of the present invention is to provide a piezoelectric and electromagnetic composite vibration energy harvester.

[0007] The technical solution to achieve the purpose of the present invention is: a piezoelectric electromagnetic composite vibration energy harvester, including a fixed bracket, a housing, a motion conversion component, a piezoelectric transducer component and an electromagnetic transducer component, wherein:

[0008] The motion conversion assembly includes a rotating shaft mounted on the housing and arranged perpendicular to the housing, a cam fixedly mounted on the rotating shaft, a connecting rod and a sliding block rotatably connected to the cam. When the sliding block is subjected to external vibration, the sliding block moves linearly. Since the sliding block and the connecting rod, and the connecting rod and the cam are connected by bearings and screws, the cam tends to rotate, driving the rotating shaft to rotate.

[0009] The piezoelectric transducer assembly includes a piezoelectric cantilever beam fixed on the rotating shaft and a magnetic mass block abutting the free end of the piezoelectric cantilever beam. The piezoelectric cantilever beam is vertically fixed around the rotating shaft. When the piezoelectric cantilever beam is static, its two ends are connected between the edge of the rotating shaft and the magnetic mass block by applying static tension to the rotating shaft and the magnetic mass block.

[0010] The electromagnetic transducer assembly includes a spring fixedly mounted on a base, a coil, and a moving magnet connected to the spring. The spring is connected to the base, the free end of the spring is connected to the moving magnet, and the coil is fixed around the spring and the moving magnet.

[0011] Furthermore, the piezoelectric cantilever beam is composed of an aluminum substrate connected by a rotating shaft and piezoelectric ceramic sheets attached to the upper and lower sides of the aluminum substrate. When the aluminum substrate bends, the piezoelectric ceramic sheets are driven to bend.

[0012] Furthermore, the outer shell is a hollow structure with a cylindrical appearance; the rotating shaft and the outer shell are connected through a bearing to reduce friction when the rotating shaft rotates, and the central axis of the outer shell is parallel to the central axis of the rotating shaft.

[0013] Furthermore, the piezoelectric cantilever beam is fixedly connected to the rotating shaft via a clamping frame provided on the rotating shaft.

[0014] Furthermore, the spring, the moving magnet and the coil are distributed on the inner side of the shell close to the rotating shaft.

[0015] Furthermore, the moving magnet and the magnetic mass block are of the same size and are placed with the same poles. The coil is wound around the moving magnet and the spring in a multi-layer winding manner, winding around the surface from one end, reaching the other end of the spring and the moving magnet, and then winding towards the original end, and so on.

[0016] Furthermore, the design process is as follows:

[0017] Step 1: Initialize the parameters according to the actual space requirements of the vibration energy harvester, including the mass of the magnet mass block M P , piezoelectric ceramic length l, width w, thickness h, moving magnet mass M EM , and coil length L;

[0018] Step 2: Equivalent the piezoelectric transducer component and the electromagnetic transducer component to a second-order system consisting of a spring-mass-damper, and construct the motion equations of the piezoelectric transducer component and the electromagnetic transducer component;

[0019] (1) Motion equation of piezoelectric transducer assembly:

[0020]

[0021] M P is the mass of the magnet mass block, u is the relative displacement of the magnet mass block, a is the external vibration acceleration, D P is the equivalent damping of the piezoelectric transducer component, K P is the equivalent stiffness of the piezoelectric transducer assembly, where: the mass of the magnet mass block: M P =ρ P V P ;

[0022] Equivalent stiffness of piezoelectric transducer assembly:

[0023] Equivalent damping of piezoelectric transducer assembly:

[0024] ρ P -Magnet mass density, V P -Magnet mass block volume, EI-bending stiffness, l-piezoelectric ceramic length, ρpiezoelectric ceramic density, vmagnet mass block vibration velocity, Apiezoelectric ceramic area, C d The drag coefficient of the magnet mass;

[0025] (2) Motion equation of electromagnetic transducer assembly:

[0026]

[0027] F mag =-k mag x m -αx m 3

[0028] M EM is the mass of the moving magnet, D EM is the equivalent damping of the electromagnetic transducer component, K EM is the equivalent stiffness of the electromagnetic transducer assembly, x(t) is the displacement of the moving magnet, k mag is the linear magnetic stiffness of the moving magnet, α is the nonlinear coefficient of the moving magnet, where: the equivalent stiffness of the electromagnetic transducer component is:

[0029] Equivalent damping of electromagnetic transducer assembly: -Magnetic force, d -Distance between the moving magnet and the magnet mass, R ext Coil external resistance, R coil The coil resistance, N, B and L are the number of coil turns, magnetic field strength and coil length respectively;

[0030] Step 3: The second-order system is in the state of underdamped decay oscillation stability at 0<ζ<1;

[0031]

[0032] Based on this, the geometric dimensions of the piezoelectric transducer component and the electromagnetic transducer component are adjusted to keep the piezoelectric-electromagnetic composite vibration energy harvester in a stable state.

[0033] Furthermore, the radius of the housing is greater than the length of the piezoelectric cantilever beam, and the geometric centers of the piezoelectric transducer component and the electromagnetic transducer component are on a straight line.

[0034] Furthermore, the cam is in the shape of a handle with one end thin and the other end thick, the thin end is connected to the rotating shaft, and the other end is connected to the connecting rod. When the connecting rod is moved by the sliding block, the cam tends to rotate, driving the rotating shaft to rotate.

[0035] Furthermore, the vibration energy of the piezoelectric cantilever beam and the electromagnetic coil is collected synchronously. When the shaft rotates and the magnets approach each other, the repulsive force generated between the magnetic poles causes the aluminum substrate to bend and the spring to reciprocate and extend. The bending of the aluminum substrate drives the bending of the piezoelectric ceramic piece to generate electrical energy, and the reciprocating linear motion of the spring causes the moving magnet to cut the magnetic lines of force in the coil, generating an induced electromotive force.

[0036] Compared with the prior art, the present invention has the following significant advantages:

[0037] 1. The present invention changes the nonlinear magnetic force between the magnet mass block at the end of the piezoelectric cantilever beam and the moving magnet at the spring end by rotating the shaft, which can continuously adjust the resonant frequency of the piezoelectric-electromagnetic coupling vibration energy harvesting device, improve the vibration energy harvesting effect, and collect vibration energy to the greatest extent.

[0038] 2. The present invention designs multi-directional energy collection in the magnetic part, which improves the utilization rate of the magnetic force in the electromagnetic part of the piezoelectric-electromagnetic coupling vibration energy collection device.

[0039] 3. The piezoelectric cantilever beam and electromagnetic coil in the present invention have a stable structure, are easy to assemble and manufacture, and are suitable for working under low-frequency and large-amplitude vibration conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 Schematic diagram of the overall structure of the piezoelectric electromagnetic composite vibration energy harvester.

[0041] Figure 2 Schematic diagram of the fixing bracket for the piezoelectric electromagnetic composite vibration energy harvester.

[0042] Figure 3 Schematic diagram of the piezoelectric electromagnetic composite vibration energy harvester shell.

[0043] Figure 4 Schematic diagram of the motion conversion component of the piezoelectric electromagnetic composite vibration energy harvester Figure 1 .

[0044] Figure 5 Schematic diagram of the motion conversion component of the piezoelectric electromagnetic composite vibration energy harvester Figure 2 .

[0045] Figure 6 Schematic diagram of the piezoelectric transducer component of the piezoelectric electromagnetic composite vibration energy harvester.

[0046] Figure 7 Schematic diagram of the electromagnetic transducer component of the piezoelectric electromagnetic composite vibration energy harvester. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0048] like Figures 1-6 As shown, a piezoelectric electromagnetic composite vibration energy harvester includes a fixed bracket 1, a shell 2, a motion conversion component 3, a piezoelectric transducer component 4 and an electromagnetic transducer component 5.

[0049] The fixed bracket 1 is mainly composed of a base plate 1-1, a fixed plate 1-2, and a fixed plate 1-3, which are fixed to the base plate 1-1 with screws 1-6 and screws 1-4 respectively. The other ends of the fixed plates 1-2 and 1-3 are connected to the rotating shaft 3-1 and the sliding block 3-6 respectively.

[0050] Housing 2 is a hollow, cylindrical structure. Mounting bracket 2-2 is welded to the edge of housing 2 via screws 2-4. A rotating shaft 3-1 is mounted perpendicular to housing 2, ensuring that the bottom of the shaft 3-1 does not contact the inner bottom of housing 2. Shaft 3-1 is rotationally connected to housing 2 via a deep-groove ball bearing 3-4, which reduces friction during rotation.

[0051] The structure of the motion transducer assembly 3 is as follows: Figure 4-Figure 5 As shown, it includes a sliding block 3-6, a connecting rod 3-8, a cam 3-2 and a rotating shaft 3-1, a bearing 3-7 connects the sliding block 3-6 and the connecting rod 3-8, a screw 3-9 connects the connecting rod and the cam, and a deep groove ball bearing 3-4 and a piezoelectric transducer assembly clamping frame 3-5 are installed in the middle and lower parts of the rotating shaft 3-1.

[0052] The cam 3-2 is in the shape of a handle with one end thin and the other end thick. The thin end is fixedly connected to the rotating shaft 3-1 and is screwed to the top of the rotating shaft 3-1 by a bolt 3-3; the other end of the cam 3-2 is connected to the connecting rod 3-8 by a screw 3-9.

[0053] Slider 3-6 is fixed vertically to the vibrating device. When the device vibrates, slider 3-6 generates linear motion. Connecting rod 3-8 connects slider 3-6 and cam 3-2. Cam 3-2, connected to connecting rod 3-8 via screw 3-9, tends to rotate, driving shaft 3-1. The thin inner and thick outer shape of cam 3-2 results in uneven mass distribution, with the center of mass positioned closer to the outer side of cam 3-2, making it easier for shaft 3-1 to rotate. The motion conversion assembly converts the linear motion of the slider caused by the device's vibration into rotational motion.

[0054] Piezoelectric transducer assembly 4 such as Figure 6 As shown, the piezoelectric cantilever beam is comprised of a piezoelectric cantilever beam mounted around a rotating shaft 3-1, a magnetic mass block 4-3, an aluminum substrate 4-1, and a piezoelectric ceramic sheet 4-2. The aluminum substrate 4-1 is fixed in the center, in the center groove of the piezoelectric transducer assembly holder 3-10. The piezoelectric ceramic sheet 4-2 is adhered to both sides of the aluminum substrate 4-1, close to the aluminum substrate 4-1. The magnetic mass block 4-3 is adhered to the free end of the piezoelectric cantilever beam. As the rotating shaft 3-1 rotates, the repulsive force between the magnets causes the aluminum substrate 4-1 to gradually bend and deform, driving the attached piezoelectric ceramic sheet 4-2 to bend and deform. This creates a potential difference across the material due to the positive piezoelectric effect. The electrical energy generated is then conducted away through a wire using the electrical conductivity of the aluminum substrate 4-1. This occurs until the equilibrium position between the magnets is restored, and the aluminum substrate 4-1 and piezoelectric ceramic sheet 4-2 return to their original shape.

[0055] Electromagnetic transducer assembly 5 such as Figure 7 As shown, the structure includes a spring 5-2, a coil 5-1, and a moving magnet 5-3. The moving magnet 5-3 of the electromagnetic transducer assembly 5 and the magnetic mass 4-3 of the piezoelectric transducer assembly 4 are installed with the same poles and at the same height. One end of the spring is fixed to the inner side of the housing 2, and the other end of the spring is connected to the moving magnet 5-3. The coil 5-1 surrounds the spring 5-2 and the moving magnet 5-3, and the axis direction of the coil 5-1, the moving magnet 5-3, and the spring 5-2 is perpendicular to the housing 2. Due to the repulsive force of the magnets, the spring 5-2 undergoes reciprocating expansion and contraction motion, and the moving magnet 5-3 moves back and forth inside the coil 5-1, causing the magnetic flux inside the coil 5-1 to change, and the coil 5-1 to generate an induced electromotive force.

[0056] Coil 5-1 is wound around the moving magnet 5-3 and spring 5-2 in multiple layers, starting from one end and wrapping around the surface. After reaching the other end of the spring 5-2 and moving magnet 5-3, it is then wound back toward the original end, repeating this process. The radius of the housing 2 is greater than the length of the piezoelectric cantilever beam, and the geometric centers of the piezoelectric transducer assembly 4 and the electromagnetic transducer assembly 5 are aligned.

[0057] Multiple piezoelectric transducer assemblies 4 and electromagnetic transducer assemblies 5 are distributed circumferentially around the housing 2. The number of piezoelectric transducer assemblies 4 and electromagnetic transducer assemblies 5 can be selected arbitrarily; in this embodiment, four are used as an example. Multiple piezoelectric cantilever beams are vertically fixed around the rotating shaft 3-1 and are evenly spaced. When static, the piezoelectric cantilever beams are connected between the edge of the rotating shaft 3-1 and the magnetic mass 4-3 at both ends by applying static tension to the rotating shaft 3-1 and the magnetic mass 4-3. Multiple electromagnetic transducer assemblies 5 are vertically connected to the inner side of the housing and are evenly spaced. The free end of the spring 5-2 is connected to the moving magnet 5-3. A coil 5-1 is fixed around the spring 5-1 and the moving magnet 5-3.

[0058] Furthermore, the design process is as follows:

[0059] Step 1: Initialize the parameters according to the actual space requirements of the vibration energy harvester, including the mass of the magnet mass block M P , piezoelectric ceramic length l, width w, thickness h, moving magnet mass M EM , and coil length L;

[0060] Step 2: Equivalent the piezoelectric transducer component and the electromagnetic transducer component to a second-order system consisting of a spring-mass-damper, and construct the motion equations of the piezoelectric transducer component and the electromagnetic transducer component;

[0061] (1) Motion equation of piezoelectric transducer assembly:

[0062]

[0063] M P is the mass of the magnet mass block, u is the relative displacement of the magnet mass block, a is the external vibration acceleration, D P is the equivalent damping of the piezoelectric transducer component, K P is the equivalent stiffness of the piezoelectric transducer assembly, where: the mass of the magnet mass block: M P =ρ P V P ;

[0064] Equivalent stiffness of piezoelectric transducer assembly:

[0065] Equivalent damping of piezoelectric transducer assembly:

[0066] ρ P-Magnet mass density, V P -Magnet mass block volume, EI-bending stiffness, l-piezoelectric ceramic length, ρpiezoelectric ceramic density, vmagnet mass block vibration velocity, Apiezoelectric ceramic area, C d The drag coefficient of the magnet mass;

[0067] (2) Motion equation of electromagnetic transducer assembly:

[0068]

[0069] F mag =-k mag x m -αx m 3

[0070] M EM is the mass of the moving magnet, D EM is the equivalent damping of the electromagnetic transducer component, K EM is the equivalent stiffness of the electromagnetic transducer assembly, x(t) is the displacement of the moving magnet, k mag is the linear magnetic stiffness of the moving magnet, α is the nonlinear coefficient of the moving magnet, where: the equivalent stiffness of the electromagnetic transducer component is:

[0071] Equivalent damping of electromagnetic transducer assembly: -Magnetic force, d -Distance between the moving magnet and the magnet mass, R ext Coil external resistance, R coil The coil resistance, N, B and L are the number of coil turns, magnetic field strength and coil length respectively;

[0072] Step 3: The second-order system is in the state of underdamped decay oscillation stability at 0<ζ<1;

[0073]

[0074] Based on this, the geometric dimensions of the piezoelectric transducer component and the electromagnetic transducer component are adjusted to keep the piezoelectric-electromagnetic composite vibration energy harvester in a stable state.

[0075] In summary, when the device vibrates, slider 3-6 generates linear motion. The coupling between connecting rod 3-8 and cam 3-2 causes shaft 3-1 to rotate. When magnetic mass 4-3 and moving magnet 5-3 approach, a repulsive force is generated. Due to the magnetic force, piezoelectric ceramic 4-2 bends and spring 5-2 expands and contracts, causing the piezoelectric ceramic 4-2 to deform and generate electrical energy. Moving magnet 5-3 cuts through magnetic lines of force, generating an electromotive force. To determine the magnetic coupling between piezoelectric transducer assembly 4 and electromagnetic transducer assembly 5, separate analysis can be performed on both components to determine the repulsive force between the two magnets. This repulsive force can then be applied to both components to achieve the coupling effect.

[0076] In the process of converting vibration mechanical energy into electrical energy, the present invention effectively combines piezoelectric and electromagnetic transduction mechanisms to improve energy conversion efficiency and further improve collection efficiency.

[0077] The above-described embodiments merely represent implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A piezoelectric and electromagnetic composite vibration energy harvester, characterized in that: It includes a fixed bracket, a housing, a motion conversion component, a piezoelectric transducer component and an electromagnetic transducer component, wherein: The motion conversion assembly includes a rotating shaft mounted on the housing and arranged perpendicular to the housing, a cam fixedly mounted on the rotating shaft, a connecting rod and a sliding block rotatably connected to the cam. When the sliding block is subjected to external vibration, the sliding block moves linearly. Since the sliding block and the connecting rod, and the connecting rod and the cam are connected by bearings and screws, the cam tends to rotate, driving the rotating shaft to rotate. The piezoelectric transducer assembly includes a piezoelectric cantilever beam fixed on the rotating shaft and a magnetic mass block abutting the free end of the piezoelectric cantilever beam. The piezoelectric cantilever beam is vertically fixed around the rotating shaft. When the piezoelectric cantilever beam is static, its two ends are connected between the edge of the rotating shaft and the magnetic mass block by applying static tension to the rotating shaft and the magnetic mass block. The electromagnetic transducer assembly includes a spring fixedly mounted on a base, a coil, and a moving magnet connected to the spring. The spring is connected to the base, the free end of the spring is connected to the moving magnet, and the coil is fixed around the spring and the moving magnet.

2. The piezoelectric-electromagnetic composite vibration energy harvester according to claim 1, characterized in that: The piezoelectric cantilever beam consists of an aluminum substrate connected by a rotating shaft and piezoelectric ceramic sheets attached to the upper and lower sides of the aluminum substrate. When the aluminum substrate bends, the piezoelectric ceramic sheets are driven to bend.

3. The piezoelectric-electromagnetic composite vibration energy harvester according to claim 1, characterized in that: The outer shell is a hollow structure with a cylindrical appearance; the rotating shaft and the outer shell are connected by a bearing to reduce the friction when the rotating shaft rotates, and the central axis of the outer shell is parallel to the central axis of the rotating shaft.

4. The piezoelectric-electromagnetic composite vibration energy harvester according to claim 2, characterized in that: The piezoelectric cantilever beam is fixedly connected to the rotating shaft via a clamping frame arranged on the rotating shaft.

5. The piezoelectric-electromagnetic composite vibration energy harvester according to claim 1, characterized in that: The spring, the moving magnet and the coil are distributed on the inner side of the shell close to the rotating shaft.

6. The piezoelectric-electromagnetic composite vibration energy harvester according to claim 5, characterized in that: The moving magnet and the magnetic mass block are of the same size and have the same poles. The coil is wound around the moving magnet and the spring in a multi-layer winding manner, starting from one end and winding around the surface. After reaching the other end of the spring and the moving magnet, it is wound back towards the original end, and so on.

7. The piezoelectric-electromagnetic composite vibration energy harvester according to claim 6, characterized in that: The design process is as follows: Step 1: Initialize the parameters according to the actual space requirements of the vibration energy harvester, including the mass of the magnet mass block M P , piezoelectric ceramic length l, width w, thickness h, moving magnet mass M EM , and coil length L; Step 2: Equivalent the piezoelectric transducer component and the electromagnetic transducer component to a second-order system consisting of a spring-mass-damper, and construct the motion equations of the piezoelectric transducer component and the electromagnetic transducer component; (1) Motion equation of piezoelectric transducer assembly: M P is the mass of the magnet mass block, u is the relative displacement of the magnet mass block, a is the external vibration acceleration, D P is the equivalent damping of the piezoelectric transducer component, K P is the equivalent stiffness of the piezoelectric transducer assembly, where: the mass of the magnet mass block: Mx = ρ P V P ; Equivalent stiffness of piezoelectric transducer assembly: Equivalent damping of piezoelectric transducer assembly: ρ P -Magnet mass density, V P -Magnet mass block volume, EI-bending stiffness, l-piezoelectric ceramic length, ρpiezoelectric ceramic density, vmagnet mass block vibration velocity, Apiezoelectric ceramic area, C d The drag coefficient of the magnet mass; (2) Motion equation of electromagnetic transducer assembly: F mag =-k mag x m -αx m 3 M EM is the mass of the moving magnet, D EM is the equivalent damping of the electromagnetic transducer component, K EM is the equivalent stiffness of the electromagnetic transducer assembly, x(t) is the displacement of the moving magnet, k mag is the linear magnetic stiffness of the moving magnet, α is the nonlinear coefficient of the moving magnet, where: the equivalent stiffness of the electromagnetic transducer component is: Equivalent damping of electromagnetic transducer assembly: d - distance between the moving magnet and the magnet mass, R ext Coil external resistance, R coil The coil resistance, N, B and L are the number of coil turns, magnetic field strength and coil length respectively; Step 3: The second-order system is in the state of underdamped decay oscillation stability at 0<ζ<1; Based on this, the geometric dimensions of the piezoelectric transducer component and the electromagnetic transducer component are adjusted to keep the piezoelectric-electromagnetic composite vibration energy harvester in a stable state.

8. The piezoelectric-electromagnetic composite vibration energy harvester according to claim 3, characterized in that: The radius of the shell is greater than the length of the piezoelectric cantilever beam, and the geometric centers of the piezoelectric transducer component and the electromagnetic transducer component are on a straight line.

9. The piezoelectric-electromagnetic composite vibration energy harvesting device according to claim 1, characterized in that: The cam is in the shape of a handle with one end thin and the other end thick. The thin end is connected to the rotating shaft, and the other end is connected to the connecting rod. When the connecting rod is moved by the sliding block, the cam has a rotation tendency, driving the rotating shaft to rotate.

10. The piezoelectric-electromagnetic composite vibration energy harvester according to claim 1, characterized in that: The vibration energy of the piezoelectric cantilever beam and the electromagnetic coil is collected synchronously. When the shaft rotates and the magnets approach each other, the repulsive force generated between the magnetic poles causes the aluminum substrate to bend and the spring to reciprocate and extend. The bending of the aluminum substrate drives the bending of the piezoelectric ceramic piece to generate electrical energy, and the reciprocating linear motion of the spring causes the moving magnet to cut the magnetic lines of force in the coil, generating an induced electromotive force.

Images