Piezoelectric-electromagnetic-friction composite energy collector for low-frequency motion of human body

Abstract

The invention discloses a piezoelectric-electromagnetic-friction composite energy collector for low-frequency movement of a human body. Belongs to the technical field of energy collection and comprises a fixing unit, a piezoelectric conversion unit, electromagnetic power generation units and friction power generation units, the piezoelectric conversion unit is installed on the upper side of the fixing unit, the electromagnetic power generation units are located on the two sides of the tail end of the piezoelectric conversion unit, and the friction power generation units are located between the piezoelectric conversion unit and the fixing unit. Through the multi-physical field coupling design, the piezoelectric effect, the electromagnetic induction and the triboelectrification effect are combined, low-frequency impact energy and vibration energy generated by human body movement can be efficiently collected, the structure is compact, and a lasting and stable self-powered solution can be provided for micro wearable equipment.

Description

Technical Field

[0001] This invention belongs to the field of energy harvesting technology, specifically a piezoelectric-electromagnetic-triboelectric composite energy harvester for low-frequency human motion. Background Technology

[0002] With the rapid development of microelectronic devices, wearable devices such as fitness trackers and smartwatches are becoming increasingly popular. Currently, wearable devices primarily rely on chemical batteries for power, which presents challenges such as frequent charging, battery life degradation, and environmental pollution, severely hindering their further development. Therefore, researchers are seeking a long-lasting, stable, and environmentally friendly energy replenishment strategy for wearable devices.

[0003] The human body, as an energy carrier with immense development potential, releases biomechanical energy throughout physiological behaviors such as respiration and limb movement. Related research indicates that the peak mechanical energy generated during human movement can reach tens of watts, providing innovative solutions to the energy problems of wearable devices. However, human movement is characterized by low frequency, complex movement patterns, and dispersed energy distribution. Therefore, how to efficiently harvest human movement energy and improve the energy density of the harvester has become a key research focus in current self-powered wearable device technology.

[0004] To address this issue, patent CN117254712A discloses a composite triboelectric-thermoelectric-piezoelectric wearable energy harvester and its preparation method. By coupling the three energy harvesting mechanisms of thermoelectricity, piezoelectricity, and triboelectricity, the efficiency of the harvester is improved, achieving the goal of comprehensively and efficiently harvesting human energy. Patent CN113037134A discloses a wearable multi-source environmental energy harvesting device that can simultaneously harvest vibration energy, solar energy, thermal energy, and radio frequency energy.

[0005] However, the above-mentioned wearable composite energy harvesting devices are heavily dependent on environmental conditions such as sunlight and temperature differences, and the manufacturing process is relatively complex. Therefore, there is a need for a device that can achieve efficient conversion of multiple energy sources through a single low-frequency human movement, in order to improve the efficiency of human energy harvesting and provide a long-lasting and stable power supply for wearable devices. Summary of the Invention

[0006] The purpose of this invention is to provide a piezoelectric-electromagnetic-triboelectric composite energy harvester for low-frequency human movement, in order to solve the shortcomings of low efficiency and complex structure of current self-powered energy harvesting devices in wearable devices. Through multi-physics field coupling design, the piezoelectric effect, electromagnetic induction and triboelectric effect are combined to efficiently collect the low-frequency impact energy and vibration energy generated by human movement, providing a long-lasting and stable self-powered solution for micro wearable devices.

[0007] A piezoelectric-electromagnetic-triboelectric composite energy harvester for low-frequency human motion includes a fixed unit, a piezoelectric conversion unit, an electromagnetic power generation unit, and a triboelectric power generation unit. The piezoelectric conversion unit is installed on the upper side of the fixed unit, the electromagnetic power generation unit is located on both sides of the end of the piezoelectric conversion unit, and the triboelectric power generation unit is located between the piezoelectric conversion unit and the fixed unit.

[0008] The fixing unit includes a base, fixing bolts, and a support frame. The support frame is fixedly installed at the right end of the base and is used to install the electromagnetic power generation unit. The piezoelectric conversion unit includes a cantilever beam, a piezoelectric sheet, a magnet one, and a magnet two. The cantilever beam is fixedly installed on the upper side of the fixing unit I by fixing bolts. The piezoelectric sheet is pasted on the upper surface of the cantilever beam. Magnet one is fixedly installed on the upper side of the free end of the cantilever beam. Magnet two is fixedly installed on the lower surface of the top of the support frame and is located above the vertical projection of magnet one. The magnetic poles of magnet one and magnet two are arranged with the same magnetic poles. The synergistic effect of the repulsive force between the magnetic poles and the elastic force of the cantilever beam causes the cantilever beam to generate large-scale nonlinear vibration to amplify the mechanical deformation and improve the energy harvesting efficiency of the piezoelectric conversion unit and the electromagnetic power generation unit.

[0009] The electromagnetic power generation unit includes two sleeves and two coils. The two sleeves are symmetrically installed inside the support frame, and the coils are sleeved on the sleeves. The central axis of the coils coincides with the position of the center of mass of the magnet when it is stationary, ensuring that the overall magnetic field distribution of the electromagnetic power generation unit is symmetrical and improving the total magnetic flux.

[0010] The triboelectric power generation unit includes a nylon friction ring, FEP film one, FEP film two, FEP film three, an FEP friction base, spring one, spring two, a mass block, a rolling ball, a rolling groove, and an insulating gasket. FEP film one and FEP film two are fixedly attached to the lower surface of the cantilever beam on one side, and connected to the cantilever beam on the other side via spring one and spring two. The mass block is fixedly installed at the ends of FEP film one and FEP film two. FEP film three is attached to the base surface. The FEP friction base is U-shaped and fixedly installed. On the base surface, an insulating pad is fixedly installed on the upper surface of the FEP friction base, and the bottom of the nylon friction ring is fixedly installed on the upper side of the insulating pad. The nylon friction ring has a rolling groove inside, and a rolling ball is installed in the rolling groove. The FEP film one and FEP film two convert the low-frequency vibration of the human body into the high-frequency friction response of the nylon friction ring under the nonlinear action of spring one, spring two and mass block, respectively. The rolling ball can convert the low-frequency impact of the human body into the high-frequency friction response of the nylon friction ring, increasing the contact area between the nylon friction ring and FEP film three and FEP friction base.

[0011] The fixing unit is used to fix the entire data acquisition device and can transmit low-frequency human motion or swaying excitation to each energy acquisition unit. The piezoelectric conversion unit can deform the cantilever beam and piezoelectric sheet under the action of external excitation and output electrical energy under the action of positive piezoelectric effect. Among them, magnet one and magnet two introduce large-scale nonlinear vibration, which improves the energy acquisition efficiency of the piezoelectric conversion unit. The electromagnetic power generation unit changes the magnetic flux through the interaction of magnet one and two sets of coils and outputs electrical energy based on the principle of electromagnetic induction. The nonlinear vibration of magnet one and magnet two also changes the frequency of magnetic flux change, which improves the energy acquisition efficiency of the electromagnetic power generation unit. The triboelectric power generation unit changes the frictional contact area between the nylon friction ring and FEP film one and FEP film two through the swaying of the cantilever beam caused by human motion, and changes the frictional contact area between the nylon friction ring and FEP film three and FEP friction base through the impact of the rolling ball, which improves the energy acquisition efficiency of the triboelectric power generation unit.

[0012] The working principle of this invention is as follows: When the human body is running, walking, or exercising, the fixed unit transmits the vibration and impact generated by the human body's movement to each energy harvesting unit. Under the action of the positive piezoelectric effect, the principle of electromagnetic induction, and the triboelectric effect, the harvester converts the mechanical energy of the human body's movement into electrical energy, realizing the piezoelectric-electromagnetic-triboelectric composite of the harvester.

[0013] The working principle of the piezoelectric conversion unit is as follows: When the low-frequency excitation generated by human movement is applied to magnet one, the cantilever beam undergoes bending deformation under the action of inertial force and gravity. Subsequently, the piezoelectric sheet attached to the upper surface of the cantilever beam also deforms, converting mechanical energy into electrical energy under the action of the positive piezoelectric effect. Then, under the action of the elastic restoring force of the cantilever beam, magnet one moves upward. Since magnet one and magnet two use the same magnetic configuration, the repulsive force between the magnetic poles, the elastic force of the cantilever beam, and the gravity of magnet one work together to construct a nonlinear dynamic structure. This structure causes the cantilever beam to generate large-amplitude nonlinear vibrations in the vertical direction, thus significantly amplifying the mechanical deformation of the cantilever beam. This further improves the energy conversion efficiency of piezoelectric conversion unit II.

[0014] The working principle of the electromagnetic power generation unit is the same as that of the piezoelectric conversion unit II. When the external low-frequency excitation causes the cantilever beam to vibrate, the magnet at the end of the cantilever beam cuts the magnetic lines of force, thereby changing the magnetic flux of the coil. According to Faraday's law of electromagnetic induction, this change in magnetic flux generates an alternating current in the coil, which efficiently converts mechanical energy into electrical energy. The nonlinear dynamic structure constructed by magnets one and two also accelerates the frequency of magnetic flux change, allowing magnet one to cut more magnetic lines of force, further improving the output electrical energy.

[0015] The first operating mode of the triboelectric generator unit is as follows: When a person walks or runs, generating a backward impact excitation, the rolling ball rolls to the right along the sliding groove under the action of the impact inertial force. During the rolling process, the nylon friction ring deforms under the action of the weight of the rolling ball, and comes into contact with the FEP friction base fixed on the base surface, generating friction. When the rolling ball moves to the bottom of the sliding groove, the nylon friction ring separates from the FEP friction base under the action of the insulating pad. When the human body moves and generates a backward impact, the inertial force of the mass block stretches the spring, causing the FE... When the P-film comes into contact with the nylon friction ring, the elastic force of the spring causes the FEP film to separate from the nylon friction ring. When the nylon friction ring periodically contacts and separates from the FEP film and the FEP friction base, based on the principle of triboelectric effect, electrons are transferred from the nylon friction ring to the FEP film and the FEP friction base. This causes the nylon friction ring to carry a static charge opposite to that of the FEP film and the FEP friction base. The resulting potential difference drives the generation of current, thereby effectively converting the impact mechanical energy of human movement into electrical energy.

[0016] The second working mode of the triboelectric power generation unit is as follows: When a human body is walking or running, generating a forward impact excitation, the rolling ball rolls to the left along the sliding groove under the action of the impact inertial force; similar to the first working mode, the nylon friction ring deforms during the rolling of the ball and comes into contact with the FEP friction base. When the rolling ball moves to the bottom of the sliding groove, the nylon friction ring separates from the FEP friction base under the action of the insulating pad; when the human body's movement generates a forward impact, the inertial force of the mass block stretches the second spring, causing the second FEP film to come into contact with the nylon friction ring. Under the action of the elastic restoring force of the second spring, the second FEP film separates from the nylon friction ring; when the nylon friction ring periodically contacts and separates from the second FEP film and the FEP friction base respectively, based on the principle of triboelectric effect, the impact mechanical energy of the human body movement is effectively converted into electrical energy.

[0017] The third operating mode of the triboelectric power generation unit is as follows: When a human body performs activities such as rope skipping or high jump, it generates vertical vibration excitation. This vibration excitation causes the cantilever beam to undergo a large downward deformation, and the nylon friction ring also deforms under the nonlinear impact of the cantilever beam. During the deformation process, the nylon friction ring contacts the FEP friction base and generates friction. When the human body's movement generates downward excitation, the mass block stretches springs one and two under the action of inertial force, causing FEP films one and two to contact the nylon friction ring. When the direction of the motion excitation changes to upward, FEP films one and two separate from the nylon friction ring under the action of the spring's elastic restoring force and the mass block's inertial force. At this time, the cantilever beam also deforms upward due to the upward vibration excitation, causing the nylon friction ring to return to its original shape and separate from the FEP friction base under the action of the insulating pad. The nylon friction ring periodically contacts and separates from FEP films one, two, and the FEP friction base, converting the vibration excitation generated by the motion into electrical energy under the action of triboelectric effect.

[0018] The fourth operating mode of the triboelectric power generation unit is as follows: When a person performs actions such as playing ball or dancing, a combined excitation of impact and vibration is generated. Under this combined excitation, the cantilever beam generates a downward nonlinear impact, causing the nylon friction ring to deform. The left and right sliding of the rolling ball under the inertial impact further expands the deformation of the nylon friction ring, increasing the contact area between the nylon friction ring and the friction film. Under the inertial force of the mass blocks at the ends of FEP film one and FEP film two, springs one and two are stretched, causing FEP film one and FEP film two to come into contact and rub against the nylon friction ring. At this time, the nylon friction ring periodically contacts and separates from FEP film one, FEP film two, FEP film three and FEP friction base, respectively, converting the combined mechanical excitation into electrical energy under the triboelectric effect.

[0019] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention integrates piezoelectric, electromagnetic, and triboelectric power generation technologies. It triggers the piezoelectric effect and electromagnetic induction through the vibration of a cantilever beam, while simultaneously utilizing a rolling sphere, piezoelectric beam deformation, and spring extension to drive the nylon-FEP friction layer to generate triboelectric charges, achieving coordinated power generation through these three mechanisms. The system synchronously converts the vibrational energy generated by human movement into piezoelectric, electromagnetic, and triboelectric energy, forming a composite energy harvesting system.

[0020] This invention uses a rolling sphere as a mechanical frequency boosting structure. Its inertial motion can convert low-frequency vibrations of the human body into high-frequency nonlinear dynamic responses of the nylon friction ring. By increasing the contact area of ​​the friction layer and the deformation amplitude of the nylon friction ring, triboelectric power generation is efficiently triggered, breaking through the bottleneck of low energy conversion efficiency of traditional triboelectric nanogenerators under low-frequency conditions.

[0021] By setting up magnets 1 and 2 with the same poles placed opposite each other, a nonlinear magnetic system is constructed. The nonlinear dynamic structure is formed by the synergistic effect of the repulsive force between the magnetic poles, the elastic force of the cantilever beam, and the gravity of magnet 1. This increases the vibration amplitude of the piezoelectric beam in the vertical direction, causes the friction ring to produce greater deformation, and further improves the energy conversion efficiency of the piezoelectric conversion unit and the electromagnetic power generation unit.

[0022] This invention has a simple structure and low cost. It significantly improves the energy recovery efficiency of low-frequency vibration through multi-physics field coupling and is suitable for self-powered scenarios of wearable devices. Attached Figure Description

[0023] Figure 1 This is a three-dimensional schematic diagram of an embodiment of the present invention; Figure 2 This is a cross-sectional view of the data collector according to an embodiment of the present invention; Figure 3 This is an exploded view of the electromagnetic power generation unit according to an embodiment of the present invention; Figure 4 For this purpose Figure 1 Enlarged schematic diagram of the installation of the insulating gasket at point A; Figure 5 This is a schematic diagram of the first triboelectric power generation mode according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the second triboelectric power generation operation mode according to an embodiment of the present invention; Figure 7 This is a schematic diagram of the third triboelectric power generation mode according to an embodiment of the present invention.

[0024] Figure 8 This is a schematic diagram of the rolling ball on the right side in the fourth triboelectric power generation mode of this invention.

[0025] Figure 9 This is a schematic diagram of the rolling ball on the left side in the fourth triboelectric power generation mode of this invention.

[0026] In the diagram: Ⅰ—Fixing Unit: 101—Base; 102—Fixing Bolt; 103—Support Frame; Ⅱ—Piezoelectric Conversion Unit: 201—Cantilever Beam; 202—Piezoelectric Sheet; 203—Magnet 1; 204—Magnet 2; Ⅲ—Electromagnetic Power Generation Unit: 301—Sleeve; 302—Coil; Ⅳ—Triboelectric Power Generation Unit: 401—Nylon Friction Ring; 402—FEP Film 1; 403—FEP Film 2; 404—FEP Film 3; 405—FEP Friction Base; 406—Spring 1; 407—Spring 2; 408—Mass Block; 409—Rolling Ball; 410—Rolling Groove; 411—Insulating Gasket. Detailed Implementation

[0027] Please see Figure 1As shown, a piezoelectric-electromagnetic-triboelectric composite energy harvester for low-frequency human motion includes a fixed unit I, a piezoelectric conversion unit II, an electromagnetic power generation unit III, and a triboelectric power generation unit IV. The piezoelectric conversion unit II is installed on the upper side of the fixed unit I, the electromagnetic power generation unit III is located on both sides of the end of the piezoelectric conversion unit II, and the triboelectric power generation unit IV is located between the piezoelectric conversion unit II and the fixed unit I.

[0028] like Figure 2 As shown, the fixed unit I includes a base 101, fixing bolts 102, and a support frame 103. The support frame 103 is fixedly installed at the right end of the base 101 and is used to install the electromagnetic power generation unit III. The piezoelectric conversion unit II includes a cantilever beam 201, a piezoelectric sheet 202, a first magnet 203, and a second magnet 204. The cantilever beam 201 is fixedly installed on the upper side of the fixed unit I by fixing bolts 102. The piezoelectric sheet 202 is pasted on the upper surface of the cantilever beam 201. The first magnet 203 is fixedly installed on the upper side of the free end of the cantilever beam 201. The second magnet 204 is fixedly installed on the lower surface of the top of the support frame 103 and is located above the vertical projection of the first magnet 203. The magnetic poles of the first magnet 203 and the second magnet 204 are arranged with the same magnetic poles. The synergistic effect of the repulsive force between the magnetic poles and the elastic force of the cantilever beam 201 causes the cantilever beam 201 to generate large-scale nonlinear vibration to amplify the mechanical deformation and improve the energy harvesting efficiency of the piezoelectric conversion unit II and the electromagnetic power generation unit III.

[0029] like Figure 3 As shown, the electromagnetic power generation unit III includes two sleeves 301 and two coils 302. The two sleeves 301 are symmetrically installed inside the support frame 103. The coils 302 are sleeved on the sleeves 301. The central axis of the coils 302 coincides with the center of mass of the magnet 203 when it is stationary, ensuring that the overall magnetic field distribution of the electromagnetic power generation unit III is symmetrical and improving the total magnetic flux.

[0030] like Figure 2 and Figure 4As shown, the triboelectric power generation unit IV includes a nylon friction ring 401, FEP film one 402, FEP film two 403, FEP film three 404, an FEP friction base 405, a spring one 406, a spring two 407, a mass block 408, a rolling ball 409, a rolling groove 410, and an insulating gasket 411. One side of FEP film one 402 and FEP film two 403 are fixedly attached to the lower surface of the cantilever beam 201. The other side of FEP film one 402 and FEP film two 403 are connected to the cantilever beam 201 via spring one 406 and spring two 407. The mass block 408 is fixedly installed at the end of FEP film one 402 and FEP film two 403. FEP film three 404 is attached to the surface of the base 101. The FEP friction base 405... The 05 is U-shaped and fixedly installed on the surface of the base 101. The insulating pad 411 is fixedly installed on the upper surface of the FEP friction base 405. The bottom of the nylon friction ring 401 is fixedly installed on the upper side of the insulating pad 411. The nylon friction ring 401 has a rolling groove 410 inside, and a rolling ball 409 is provided in the rolling groove 410. The FEP film 1 402 and FEP film 2 403 convert the low-frequency vibration of the human body into the high-frequency friction response of the nylon friction ring 401 under the nonlinear action of the spring 1 406, the spring 2 407 and the mass block 408, respectively. The rolling ball 409 can convert the low-frequency impact of the human body into the high-frequency friction response of the nylon friction ring 401, increasing the contact area between the nylon friction ring 401 and the FEP film 3 404 and the FEP friction base 405.

[0031] The fixing unit I is used to fix the entire data acquisition device and can transmit low-frequency human motion or swaying excitation to each energy acquisition unit; the piezoelectric conversion unit II can cause the cantilever beam 201 and piezoelectric plate 202 to deform under the action of external excitation, and output electrical energy under the action of positive piezoelectric effect. Among them, magnet one 203 and magnet two 204 introduce large-scale nonlinear vibration, which improves the energy acquisition efficiency of piezoelectric conversion unit II; the electromagnetic power generation unit III changes the magnetic flux through the interaction of magnet one 203 and two sets of coils 302, and outputs power based on the principle of electromagnetic induction. The nonlinear vibrations of magnet 203 and magnet 204 also change the frequency of magnetic flux change, thus improving the energy harvesting efficiency of electromagnetic power generation unit III. Triboelectric power generation unit IV changes the frictional contact area between nylon friction ring 401 and FEP film 402 and FEP film 2 403 by the swing of cantilever beam 201 caused by human movement, and changes the frictional contact area between nylon friction ring 401 and FEP film 3 404 and FEP friction base 405 by the impact of rolling ball 409, thus improving the energy harvesting efficiency of triboelectric power generation unit IV.

[0032] The working principle of this invention is as follows: When the human body is running, walking, or exercising, the fixed unit I transmits the vibration and impact generated by the human body's movement to each energy harvesting unit. Under the action of the positive piezoelectric effect, the principle of electromagnetic induction, and the triboelectric effect, the harvester converts the mechanical energy of the human body's movement into electrical energy, realizing the piezoelectric-electromagnetic-triboelectric composite of the harvester.

[0033] like Figure 2 and Figure 5 As shown, the working principle of piezoelectric conversion unit II is as follows: When the low-frequency excitation generated by human movement acts on magnet 203, the cantilever beam 201 undergoes bending deformation under the action of inertial force and gravity. Subsequently, the piezoelectric sheet 202 attached to the upper surface of the cantilever beam 201 also deforms, converting mechanical energy into electrical energy under the action of the positive piezoelectric effect. Then, under the action of the elastic restoring force of the cantilever beam 201, magnet 203 moves upward. Since magnet 203 and magnet 204 use the same magnetic configuration, the repulsive force between the magnetic poles, the elastic force of the cantilever beam 201, and the gravity of magnet 203 work together to construct a nonlinear dynamic structure. This structure causes the cantilever beam 201 to generate large-amplitude nonlinear vibrations in the vertical direction, thus significantly amplifying the mechanical deformation of the cantilever beam 201. This further improves the energy conversion efficiency of piezoelectric conversion unit II.

[0034] like Figure 3 As shown, the working principle of the electromagnetic power generation unit III is as follows: the excitation method is the same as that of the piezoelectric conversion unit II. When the external low-frequency excitation causes the cantilever beam 201 to vibrate, the magnet 203 placed at the end of the cantilever beam 201 cuts the magnetic lines of force, thereby changing the magnetic flux of the coil 302. According to Faraday's law of electromagnetic induction, this change in magnetic flux generates an alternating current in the coil 302, which efficiently converts mechanical energy into electrical energy. The nonlinear dynamic structure constructed by the magnet 203 and the magnet 204 also accelerates the frequency of magnetic flux change, allowing the magnet 203 to cut more magnetic lines of force, further improving the output electrical energy.

[0035] like Figure 4 and Figure 5As shown, the first working mode of the triboelectric power generation unit IV is as follows: When a human body is walking or running and generates a backward impact excitation, the rolling ball 409 rolls to the right along the sliding groove 410 under the action of the impact inertial force. During the rolling of the rolling ball 409, the nylon friction ring 401 is deformed by the gravity of the rolling ball 409 and comes into contact with the FEP friction base 405 fixed on the surface of the base 101 and generates friction. When the rolling ball 409 moves to the bottom position of the sliding groove 410, the nylon friction ring 401 separates from the FEP friction base 405 under the action of the insulating pad 411. When the human body moves and generates a backward impact, the inertial force of the mass block 408 stretches the spring 406, causing... The FEP film 402 comes into contact with the nylon friction ring 401, and the spring 406 causes the FEP film 402 to separate from the nylon friction ring 401. When the nylon friction ring 401 periodically contacts and separates from the FEP film 402 and the FEP friction base 405, based on the principle of triboelectric effect, this process causes electrons to transfer from the nylon friction ring 401 to the FEP film 402 and the FEP friction base 405, resulting in the nylon friction ring 401 carrying a static charge opposite to that of the FEP film 402 and the FEP friction base 405. The resulting potential difference drives the generation of current, thereby effectively converting the impact mechanical energy of human movement into electrical energy.

[0036] like Figure 6 As shown, the second working mode of the triboelectric power generation unit IV is as follows: When a person walks or runs, generating a forward impact excitation, the rolling ball 409 rolls to the left along the sliding groove 410 under the action of the impact inertial force; similar to the first working mode, during the rolling process of the rolling ball 409, the nylon friction ring 401 deforms and comes into contact with the FEP friction base 405. When the rolling ball 409 moves to the bottom of the sliding groove 410, the nylon friction ring 401 separates from the FEP friction base 405 under the action of the insulating pad 411. When the human body moves and generates a forward impact, the inertial force of the mass block 408 stretches the spring 407, causing the FEP film 403 to come into contact with the nylon friction ring 401. Under the elastic restoring force of the spring 407, the FEP film 403 separates from the nylon friction ring 401. When the nylon friction ring 401 periodically contacts and separates from the FEP film 403 and the FEP friction base 405, based on the principle of triboelectric effect, the impact mechanical energy of the human body movement is effectively converted into electrical energy.

[0037] like Figure 7As shown, the third working mode of the triboelectric power generation unit IV is as follows: When a human body performs activities such as rope skipping or high jump, it generates vertical vibration excitation; these vibration excitations cause the cantilever beam 201 to undergo a large downward deformation, and the nylon friction ring 401 also deforms under the nonlinear impact of the cantilever beam 201; during the deformation process, the nylon friction ring 401 contacts the FEP friction base 405 and generates friction; when the human body's movement generates downward excitation, the mass block 408 stretches the spring 406 and the spring 407 under the action of inertial force, causing the FEP film 402 and the FEP film 403 to contact the nylon friction ring 401, and when the movement excitation... When the excitation direction changes upward, FEP film 1 402 and FEP film 2 403 separate from the nylon friction ring 401 under the action of the spring elastic restoring force and the inertial force of the mass block 408. At this time, the cantilever beam 201 also deforms upward due to the upward vibration excitation, causing the nylon friction ring 401 to return to its original shape and separate from the FEP friction base 405 under the action of the insulating pad 411. The nylon friction ring 401 periodically contacts and separates from FEP film 1 402, FEP film 2 403 and FEP friction base 405 respectively, and converts the vibration excitation generated by the motion into electrical energy under the action of triboelectric effect.

[0038] like Figure 8 and Figure 9 As shown, the fourth operating mode of the triboelectric power generation unit IV is as follows: When a person performs actions such as playing ball or dancing, a combined excitation of impact and vibration is generated. Under this combined excitation, the cantilever beam 201 generates a downward nonlinear impact, causing the nylon friction ring 401 to deform. The left and right sliding of the rolling ball 409 under the action of inertial impact further expands the deformation of the nylon friction ring 401, increasing the contact area between the nylon friction ring 401 and the friction film. Under the action of the inertial force of the mass block 408 at the end of FEP film one 402 and FEP film two 403, spring one 406 and spring two 407 are stretched, causing FEP film one 402 and FEP film two 403 to come into contact and rub against the nylon friction ring 401. At this time, the nylon friction ring 401 periodically contacts and separates from FEP film one 402, FEP film two 403, FEP film three 404 and FEP friction base 405, respectively, and converts the combined mechanical excitation into electrical energy under the action of triboelectric effect.

Claims

1. A piezoelectric-electromagnetic-triboelectric composite energy harvester for low-frequency human motion, characterized in that: It includes a fixed unit (Ⅰ), a piezoelectric conversion unit (Ⅱ), an electromagnetic power generation unit (Ⅲ), and a triboelectric power generation unit (Ⅳ). The piezoelectric conversion unit (Ⅱ) is installed on the upper side of the fixed unit (Ⅰ), the electromagnetic power generation unit (Ⅲ) is located on both sides of the end of the piezoelectric conversion unit (Ⅱ), and the triboelectric power generation unit (Ⅳ) is located between the piezoelectric conversion unit (Ⅱ) and the fixed unit (Ⅰ).

2. The piezoelectric-electromagnetic-triboelectric composite energy harvester for low-frequency human motion according to claim 1, characterized in that: The fixing unit (Ⅰ) includes a base (101), fixing bolts (102) and a support frame (103). The support frame (103) is fixedly installed at the right end of the base (101) and is used to install the electromagnetic power generation unit (Ⅲ). The piezoelectric conversion unit (II) includes a cantilever beam (201), a piezoelectric sheet (202), a magnet (203), and a magnet (204). The cantilever beam (201) is fixedly installed on the upper side of the fixed unit (I) by fixing bolts (102). The piezoelectric sheet (202) is pasted on the upper surface of the cantilever beam (201). The magnet (203) is fixedly installed on the upper side of the free end of the cantilever beam (201). The magnet (204) is fixedly installed on the lower surface of the top of the support frame (103) and located above the vertical projection of the magnet (203). The magnetic poles of the magnet (203) and the magnet (204) are arranged with the same magnetic poles. The electromagnetic power generation unit (Ⅲ) includes two sleeves (301) and two coils (302). The two sleeves (301) are symmetrically installed inside the support frame (103). The coils (302) are sleeved on the sleeves (301). The central axis of the coils (302) coincides with the center of mass of the magnet (203) when it is stationary. The triboelectric power generation unit (Ⅳ) includes a nylon friction ring (401), FEP film one (402), FEP film two (403), FEP film three (404), an FEP friction base (405), spring one (406), spring two (407), a mass block (408), a rolling ball (409), a rolling groove (410), and an insulating pad (411). One side of FEP film one (402) and FEP film two (403) are fixedly pasted to the lower surface of the cantilever beam (201), and the other side of FEP film one (402) and FEP film two (403) are connected to the cantilever beam (201) through spring one (406) and spring two (407). The mass block (408) is fixedly installed at the end of FEP film one (402) and FEP film two (403). FEP film three (404) is pasted on the surface of the base (101). The base (405) is U-shaped and fixedly installed on the surface of the base (101). The insulating pad (411) is fixedly installed on the upper surface of the FEP friction base (405). The bottom of the nylon friction ring (401) is fixedly installed on the upper side of the insulating pad (411). The nylon friction ring (401) is provided with a rolling groove (410) inside. The rolling groove (410) is provided with a rolling ball (409). The FEP film one (402) and FEP film two (403) convert the low-frequency vibration of the human body into the high-frequency friction response of the nylon friction ring (401) under the nonlinear action of the spring one (406), the spring two (407) and the mass block (408), respectively. The rolling ball (409) can convert the low-frequency impact of the human body into the high-frequency friction response of the nylon friction ring (401), increasing the contact area between the nylon friction ring (401) and the FEP film three (404) and the FEP friction base (405).

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