Wind turbine generator vibration detection device

Abstract

The invention belongs to the technical field of wind turbine generator operation and maintenance, and particularly relates to a wind turbine generator vibration detection device which comprises a base. A vibration detection unit including a vibration sensor; the energy collecting part comprises a multi-order cantilever beam array and an energy storage capacitor, and a piezoelectric plate is arranged on the multi-order cantilever beam array and used for converting mechanical vibration energy into electric energy; the rectifying part is used for converting the alternating current output by the piezoelectric plate into one-way current; through the integrated design of broadband energy harvesting, mechanical rectification and self-energized monitoring, full-scene vibration detection of key components of the wind turbine generator is realized, and the problems that an existing device is dependent on power supply, narrow in frequency band adaptation and poor in reliability in a severe environment are solved. Vibration detection, energy collection and rectification are highly coordinated in spatial layout, mechanical transmission and energy flow direction, and are physically isolated from a power supply circuit, so that the performance is improved, mutual interference is avoided, and real high-integration and high-reliability self-energized detection is realized.

Description

Technical Field

[0001] This invention belongs to the field of wind turbine operation and maintenance, specifically a wind turbine vibration detection device. Background Technology

[0002] During long-term operation, key components of wind turbines, such as the drivetrain (gearbox, generator), tower, and blade roots, can experience wear, fatigue cracks, and other failures due to mechanical vibration. Problems like blade stall flutter and tower bending vibration can not only reduce power generation efficiency but, in severe cases, lead to turbine shutdown or even structural collapse. Therefore, real-time vibration monitoring of wind turbines is necessary, involving the collection and analysis of mechanical vibration signals from key components to diagnose early-stage faults such as bearing damage and imbalance.

[0003] Since offline detection cannot meet the needs of real-time early warning, most existing wind turbines adopt online vibration detection technology. Sensor systems are installed on the components of the wind turbine, and vibration data of the components are collected in real time through vibration sensors. The detection data is then transmitted to the terminal of the operation and maintenance center via wired or wireless transmission. In this way, staff can remotely monitor the operation status of the wind turbine in real time.

[0004] However, existing technologies still have some shortcomings: some devices rely on external cables for power supply, which makes wiring difficult and costly in offshore or remote onshore wind farms; some devices use disposable batteries for power supply, which have limited endurance and usually need to be replaced every 3-6 months, resulting in high operation and maintenance costs; existing wind turbine technology for online detection is limited by power supply methods or environmental adaptability, and these defects directly restrict the reliability and economy of wind turbine vibration monitoring.

[0005] Therefore, the present invention provides a vibration detection device for wind turbine generators. Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, at least one technical problem raised in the background art is solved.

[0007] The technical solution adopted by the present invention to solve its technical problem is as follows: The wind turbine vibration detection device of the present invention includes a base disposed at the measured area of ​​the wind turbine, and further includes: The vibration detection unit includes a vibration sensor that collects vibration data from the wind turbine generator. The vibration detection unit also includes a processing module and a communication module for processing the vibration data. An energy harvesting unit includes a multi-stage cantilever beam array and an energy storage capacitor. The multi-stage cantilever beam array is equipped with a piezoelectric element, which converts the mechanical vibration energy of the multi-stage cantilever beam array into electrical energy and stores it in the energy storage capacitor to power the vibration detection unit. The rectifier is connected to the piezoelectric element via a wire and converts the alternating current output by the piezoelectric element into a unidirectional current.

[0008] Preferably, the sensing surface of the vibration sensor is rigidly connected to the base and perpendicular to the vibration direction of the wind turbine, with an error of no more than 5°.

[0009] Preferably, the multi-stage cantilever beam array includes several cantilever beams of different lengths, each corresponding to a different resonant frequency, capturing different broadband vibration energies, and the several cantilever beams are evenly distributed in a ring.

[0010] Preferably, the energy harvesting unit further includes: A mass block is slidably disposed at the end of the cantilever beam, and the contact surface between the mass block and the cantilever beam is provided with a damping structure. A positioning spring is installed between the cantilever beam and the mass block.

[0011] Preferably, the energy harvesting unit further includes: An installation groove is formed on the cantilever beam; A clamping mechanism is used to fix the piezoelectric sheet in the mounting groove.

[0012] Preferably, the rectifier section includes: A sealed housing with an internal cavity; Two contacts are respectively located at both ends of the cavity. The input terminals of the two contacts are connected to the positive electrode of the piezoelectric element, and the connection is open and closed. The output terminals of the two contacts are connected to the positive electrode of the energy storage capacitor. The negative electrode of the energy storage capacitor is connected to the negative electrode of the vibration detection unit through a common ground wire. The negative electrode of the piezoelectric element is connected to the common ground wire.

[0013] Preferably, the rectifier section further includes: A swing arm disposed within the housing is oscillating, with the bottom end of the swing arm inserted into the cavity; A connector is provided at the bottom of the swing arm. The connector is made of conductive material. After the swing arm swings, the connector alternately contacts the two contacts, filling the gap between the contact input end and the positive electrode of the piezoelectric element, so that the contact is connected to the piezoelectric element circuit.

[0014] Preferably, the rectifier section further includes: Two steel balls, made of ferromagnetic material, are slidably disposed within the cavity. The steel balls are separately disposed from the contact point to fill the connection between the contact input end and the positive electrode of the piezoelectric element, thereby enabling the contact point to be connected to the piezoelectric element circuit. Two coils wound around the two ends inside the cavity form an excitation zone. When the coils are energized, they drive the steel balls to move, causing the two sets of steel balls to alternately contact the contacts. The two ends of the coils are respectively connected to the positive and negative poles of the piezoelectric sheet. A return spring used to move the steel ball away from the contact point.

[0015] Preferably, the vibration sensor is powered by an independent battery, its ground wire is physically isolated from the common ground wire, and multiple sets of the piezoelectric elements are connected in parallel.

[0016] Preferably, the two steel balls are located in the middle of the cavity, and the two coils are an integrated wire structure, with the two coils wound in opposite directions.

[0017] The beneficial effects of this invention are as follows: 1. The wind turbine vibration detection device of the present invention integrates multiple cantilever beams of different lengths through a multi-stage variable stiffness piezoelectric vibrator design, and is equipped with a sliding tungsten steel mass block to achieve full-frequency vibration energy coverage of -Hz. Furthermore, the combination of springs and damping avoids cantilever beam breakage caused by high-frequency impacts, ensuring energy capture stability under different operating conditions.

[0018] 2. The wind turbine vibration detection device of this invention is equipped with a ball-bearing mechanical rectifier. A miniature coil drives a steel ball to reciprocate through an alternating magnetic field, achieving unidirectional mechanical conduction, improving energy conversion efficiency, and reducing circuit size. This not only avoids the effects of high temperature and salt spray on electronic components but also replaces adhesive bonding with wedge-shaped piezoelectric fixing, reducing the piezoelectric element detachment rate and greatly improving the device's lifespan and long-term operational reliability in harsh environments such as high temperature, high humidity, and salt spray.

[0019] 3. The wind turbine vibration detection device of this invention achieves full-scenario vibration detection of key components of wind turbines through an integrated design of wideband energy harvesting, mechanical rectification, and self-powered monitoring. This solves the problems of existing devices such as power supply dependence, narrow frequency band compatibility, and poor reliability in harsh environments. Vibration detection, energy harvesting, and rectification are highly coordinated in spatial layout, mechanical transmission, and energy flow, and are physically isolated from the power supply circuit. This improves performance while avoiding mutual interference, achieving truly high integration, high reliability, and self-powered detection. The device has a compact overall structure, is easy to install, and has high energy conversion efficiency. It can be widely used in onshore, offshore, and floating wind farms, providing strong support for predictive maintenance of wind turbines. Attached Figure Description

[0020] The invention will now be further described with reference to the accompanying drawings.

[0021] Figure 1 This is a partial schematic diagram of the assembly state of the invention with the tower of the wind turbine; Figure 2 This is an exploded view of the internal structure of the base, the base, and the expansion sleeve of the present invention; Figure 3 This is a 3D view of the internal structure of the base; Figure 4 This is a cross-sectional view of the rectifier section in Embodiment 4 of the present invention; Figure 5 This is a rear view of the installation structure of the mass block and cantilever beam; Figure 6 This is a front view of the piezoelectric element and cantilever beam mounting structure; Figure 7 This is a perspective view of the steel ball, coil, and contact points in Embodiment 4 of the present invention; Figure 8 This is a perspective view of the connector and contact points according to Embodiment 3 of the present invention; In the diagram: 1. Base; 2. Vibration detection unit; 21. Vibration sensor; 3. Energy harvesting unit; 31. Multi-stage cantilever beam array; 32. Piezoelectric element; 33. Energy storage capacitor; 34. Mass block; 35. Positioning spring; 36. Mounting slot; 37. Clamping mechanism; 4. Rectifier unit; 41. Housing; 42. Cavity; 43. Contact; 44. Swing rod; 45. Connector; 46. Steel ball; 47. Coil; 48. Return spring; 5. Expansion sleeve; 6. Extension contact. Detailed Implementation

[0022] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0023] Example 1 like Figure 1-6 As shown in the figure, a wind turbine vibration detection device according to an embodiment of the present invention includes a base 1 disposed at the measured area of ​​the wind turbine, and further includes: Vibration detection unit 2 includes a vibration sensor 21, which collects vibration data of the wind turbine. The vibration detection unit 2 also includes a processing module and a communication module for processing the vibration data. The energy harvesting unit 3 includes a multi-stage cantilever beam array 31 and an energy storage capacitor 33. The multi-stage cantilever beam array 31 is provided with a piezoelectric element 32, which converts the mechanical vibration energy of the multi-stage cantilever beam array 31 into electrical energy and stores it in the energy storage capacitor 33 to power the vibration detection unit 2. The rectifier 4 is connected to the piezoelectric element 32 via a wire, and converts the alternating current output by the piezoelectric element 32 into a unidirectional current.

[0024] Specifically, the vibration detection unit 2, energy harvesting unit 3, and rectifier unit 4 are all located inside the base 1. The base 1 is made of aluminum alloy, preferably 3mm thick, which is lightweight and rigid. The vibration sensor 21 can be an FBG fiber Bragg grating sensor, a MEMS microelectromechanical system accelerometer, or a piezoelectric accelerometer, to directly sense vibration acceleration, velocity, or displacement, thereby collecting vibration data of the wind turbine. The vibration sensor 21 is located in the vibration-sensitive area on the base, directly contacting the measured components in the wind turbine, such as the tower wall and the surface of the gearbox bearing housing. The base of the vibration sensor 21 is connected to the base 1 by threads, and a 0.5mm thick silicone pad is added to the contact surface to ensure rigid vibration transmission and isolate high-frequency noise, avoiding noise interference with detection accuracy.

[0025] The processing module includes an edge computing unit, which receives and processes the detection data output by the vibration sensor 21. The vibration sensor 21 converts mechanical vibration into an analog electrical signal of 0-3.3V, with a sampling rate set to 1kHz and a circuit impedance matching of 50Ω to avoid distortion during signal transmission. The analog signal is transmitted to the edge computing unit through shielded twisted-pair cable. The edge computing unit filters, amplifies, and extracts features from the signal to obtain the key vibration parameters of the monitored component. The communication module adopts a wireless communication transmission architecture, such as using ZigBee wireless transmission technology, to reduce wiring costs. At the same time, a data encryption mechanism is designed to ensure transmission security. The communication module transmits the processed detection data to an external operation and maintenance system so that staff can receive and view the vibration detection data of the wind turbine on a terminal.

[0026] A multi-stage cantilever beam array 31 is arranged around the vibration sensor 21, and both are mounted on the base 1 with a distance of ≤8mm between them to ensure synchronous capture of vibration energy and avoid energy transfer delay. The piezoelectric element 32 is made of PZT-5H material. After bending deformation, the piezoelectric element 32 generates alternating current: when the PZT-5H piezoelectric element 32 is squeezed by the bending deformation of the cantilever beam, the internal crystal lattice is polarized, and equal and opposite charges are generated on the surface, forming an alternating electric field with the same frequency as the vibration frequency. This alternating voltage / current is formed by leading it out through the electrodes. Through the cooperation of the multi-stage cantilever beam array 31 and the piezoelectric element 32, the vibration energy is converted into electrical energy, realizing the energy capture function.

[0027] In this embodiment, the rectifier 4 can be an electronic rectifier located on the base 1, which rectifies the output current of the piezoelectric element 32. The piezoelectric element 32 generates alternating positive and negative current, which must be converted into direct current with a single direction by the rectifier 4 in order to charge the energy storage capacitor 33 and thus power the electronic device.

[0028] The energy storage capacitor 33 can be a 100μF / 50V miniature energy storage capacitor 33, configured with a DC-DC voltage regulator module. The energy storage capacitor 33 is fixed by epoxy resin potting with a potting thickness of 2mm.

[0029] The working process of this detection device is as follows: When the wind turbine is running, the target monitoring components (such as gearbox and tower) vibrate: transmission chain vibration, such as the characteristic frequency vibration of the high-speed shaft bearing of the gearbox at 200-800Hz, and the vibration of gear meshing at 200-500Hz. The vibration of the wind turbine is transmitted to the device base 1 through the tower or gearbox. The vibration sensor 21 senses the vibration, outputs an analog signal, which is converted into a digital signal by the processing module and then sent to the terminal of the external operation and maintenance system through the wireless communication module to complete the detection cycle. The vibration of the wind turbine is synchronously transmitted to the cantilever beam, causing the cantilever beam to bend and vibrate, which causes the piezoelectric sheet 32 ​​to deform and generate an alternating voltage. The alternating voltage is input to the rectifier for rectification: the rectified DC power is stored in the energy storage capacitor 33 to power the processing module and communication module in the vibration detection unit 2.

[0030] In another embodiment, the sensing surface of the vibration sensor 21 is rigidly connected to the base 1 and is perpendicular to the vibration direction of the wind turbine, with an error of no more than 5°.

[0031] Specifically, the perpendicularity error between the sensor's sensing surface and the vibration direction is ≤5° to ensure that the vibration signal is transmitted without attenuation.

[0032] like Figure 5-6 As shown, the multi-stage cantilever beam array 31 includes several cantilever beams of different lengths, each corresponding to a different resonant frequency, capturing different broadband vibration energies, and the several cantilever beams are evenly distributed in a ring.

[0033] Specifically, the multi-stage cantilever beam array 31 includes at least three sets of cantilever beams of different lengths. The cantilever beams are rectangular thin sheets with lengths of 25mm, 35mm, and 45mm, corresponding to resonant frequencies of 15Hz, 25Hz, and 35Hz, respectively. The cantilever beam structure is a composite structure: the top and bottom are metal electrode layers, such as nickel or silver, and the middle layer is PZT-5H ceramic material. The roots of the cantilever beams are fixed to the base 1 by laser welding or other methods to ensure lossless transmission of vibrational energy.

[0034] A single cantilever beam has only one resonant frequency, limiting its efficient power generation to a very narrow frequency range. Wind turbines, however, have a wide vibration frequency range, such as 2-50Hz, which a single beam cannot accommodate. This embodiment integrates three cantilever beams of different lengths and natural frequencies onto a single base 1. Each cantilever beam is equipped with a piezoelectric element 32 and a mass block 34. Thus, regardless of whether the vibration frequency is low (e.g., 15Hz), medium (e.g., 25Hz), or high (e.g., 35Hz), at least one cantilever beam is always in a resonant state, significantly widening the effective operating frequency band.

[0035] like Figure 5 As shown, the energy harvesting unit 3 further includes: A mass block 34 is slidably disposed at the end of the cantilever beam, and the contact surface between the mass block 34 and the cantilever beam is provided with a damping structure. A positioning spring 35 is provided between the cantilever beam and the mass block 34.

[0036] Specifically, the end of the cantilever beam is a free end, and the mass block 34 is preferably, but not limited to, made of tungsten steel. The free end and the mass block 34 adopt a spring-damping combination. The two ends of the positioning spring 35 are connected to the cantilever beam and the mass block 34 respectively. The spring stiffness is 2N / mm and the damping coefficient is 0.1Ns / m, forming a rigid fixed and flexible vibration structure to avoid high-frequency impact fracture. The mass blocks 34 on the three sets of cantilever beams weigh 5g, 8g, and 12g respectively, with a sliding stroke of 5mm. By adjusting the position of the mass blocks 34, the equivalent cantilever length of the cantilever beam is changed, thereby achieving full frequency band coverage of 10-50Hz, making it more applicable.

[0037] It should be noted that the mass block can be installed on the back or left and right side walls of the cantilever beam. The movement of the mass block 34 can be controlled by integrating a micro motor on the cantilever beam or by manual operation. By sliding the tungsten steel mass block 34 at the end of the cantilever beam, the resonant frequency of the cantilever beam can be adjusted to capture the mechanical energy of vibration in the full frequency band of 10-50Hz.

[0038] like Figure 6 As shown, the energy harvesting unit 3 further includes: A mounting groove 36 is formed on the cantilever beam; The piezoelectric sheet 32 ​​is fixed in the mounting groove 36 by the clamping mechanism 37.

[0039] Specifically, each cantilever beam has a mounting groove 36; the clamping mechanism 37 includes brass wedges and set screws. The wedges are located on both sides of the mounting groove 36. The brass wedges are pushed by the threaded set screws to press the piezoelectric sheet 32 ​​for clamping and fixing. The contact surface between the wedges and the piezoelectric sheet 32 ​​is covered with a 0.1mm thick silicone pad. The piezoelectric sheet 32 ​​is embedded in the mounting groove 36 of the cantilever beam and mechanically fixed by the wedge clamping mechanism 37, achieving adhesive-free assembly.

[0040] Example 2 like Figure 4 As shown in Comparative Embodiment 1, another embodiment of the present invention is as follows: the rectifier 4 includes: A sealed housing 41, wherein the interior of the housing 41 is provided with a cavity 42; Two contacts 43 are respectively located at both ends of the cavity 42. The input terminals of the two contacts 43 are connected to the positive terminal of the piezoelectric element 32, and the connection is controlled to open and close. The output terminals of the two contacts 43 are connected to the positive terminal of the energy storage capacitor 33. The negative terminal of the energy storage capacitor 33 is connected to the negative terminal of the vibration detection unit 2 through a common ground wire. The negative terminal of the piezoelectric element 32 is connected to the common ground wire.

[0041] Specifically, the housing 41 is fixed to the base 1 with screws. The housing 41 is made of insulating material. The cavity 42 is a cylindrical cavity with its axis perpendicular to the cantilever beam array, isolating it from the external environment. The sealed housing 41 isolates it from harsh environments such as salt spray and dust, making it suitable for offshore wind power scenarios. The internal cavity 42 provides a guide rail for the movement of the steel ball 46. The cavity 42 adopts a heat insulation design to prevent vibration heat sources from affecting the stability of the rectifier unit 4. The electrode contacts 43 are made of gold-plated copper sheets and are connected to the piezoelectric element 32 through wires. Both ends of the cavity 42 are provided with extension contacts 6 that are connected to the positive terminal of the piezoelectric element 32. The extension contacts 6 do not contact the contacts 43. The common ground wire is connected to the negative terminal of the piezoelectric element 32, the negative terminal of the energy storage capacitor 33, and the negative terminal of the communication module, forming a closed current loop. Initially, the two contacts 43 are disconnected from the positive electrode of the piezoelectric element 32. After one of the contacts 43 is closed and connected to the positive electrode of the piezoelectric element 32, the current generated by the piezoelectric element 32 is transmitted to the energy storage capacitor 33 through the contact 43.

[0042] It should be noted that the layout of public wiring and other circuits is a basic technique in circuit system installation. The distribution of wires and circuits is selected according to the specific product type. For the sake of the key structure in the application embodiment, the specific circuits such as wires are not shown in the attached drawings. It should be understood that those skilled in the art know and can implement the circuit installation.

[0043] Example 3 like Figure 8 As shown in Comparative Embodiment 2, another embodiment of the present invention is as follows: the rectifier 4 further includes: A swing rod 44 is provided inside the housing 41, and the bottom end of the swing rod 44 is inserted into the cavity 42; A connector 45 is provided at the bottom of the swing arm 44. The connector 45 is made of conductive material. After the swing arm 44 swings, the connector 45 alternately contacts the two contacts 43, filling the connection between the input end of the contact 43 and the positive electrode of the piezoelectric element 32, so that the contact 43 and the piezoelectric element 32 are connected in circuit.

[0044] Specifically, in this embodiment, the rectifier 4 is a mechanical rectifier. The pendulum 44 is vertically positioned in the center of the cavity 42 and can swing slightly left and right. The connector 45 is fixed to both sides of the lower end of the conductive pendulum 44 as a counterweight, which can also increase the inertia of the pendulum 44. The piezoelectric sheet 32 ​​is connected to the circuit in the cavity 42 through a wire. After the connector 45 moves to the left or right end, it simultaneously contacts the extension contact 6 and the contact 43 on the same side to achieve circuit connection. The entire process is based on inertia, mechanical movement, and circuit switching. The fan vibration causes the piezoelectric sheet 32 ​​to generate electricity, which drives the pendulum 44 in the rectifier to swing. After the pendulum 44 swings, it alternately contacts the two electrodes to connect the circuit. Since both contacts 43 are connected to the positive terminal of the capacitor and the negative terminal of the capacitor is connected to the common ground wire, and the steel ball 46 alternately contacts the two contacts 43, the current always flows to the capacitor through a single contact 43 to achieve unidirectional rectification and avoid reverse discharge of the capacitor.

[0045] Example of a current loop: Connector 45 contacts left contact 43, positive current loop: piezoelectric element 32 positive terminal → connector 45 → left contact 43 → energy storage capacitor 33 positive terminal → energy storage capacitor 33 negative terminal → common ground wire → piezoelectric element 32 negative terminal; Connector 45 contacts right contact 43, reverse current loop: negative terminal of piezoelectric element 32 → common ground wire → negative terminal of energy storage capacitor 33 → positive terminal of energy storage capacitor 33 → right contact 43 → positive terminal of piezoelectric element 32.

[0046] The rectification principle is fundamental to rectification technology, so it will not be elaborated here.

[0047] In this embodiment, the same source, namely vibration, is used to simultaneously complete the functions of power generation and rectification through two parallel mechanical paths without consuming any external power, thus achieving self-powering capability. This is more suitable for the operating environment of wind turbine units where battery swapping is difficult.

[0048] Example 3 proposes a mechanical rectifier scheme, which can rectify the AC power output from the piezoelectric element 32. However, it still has some minor issues, such as: 1. The pendulum 44 needs to swing by vibration inertia. However, the vibration energy of wind power is mainly concentrated in the bearing housing / tower, such as the 30Hz meshing vibration of the gearbox. As an additional mechanical load, the pendulum 44 will divert 20-30% of the vibration energy, affecting the energy capture efficiency of the piezoelectric sheet 32.

[0049] 2. The vibration amplitude of the wind turbine is 0.1-10mm, and the number of daily swings of the 44-inch pendulum may be greater than 4×10. 6 The wear rate of contact 43 material is >0.5mg / 10. 6The contact resistance increased from 0.1Ω to 5Ω within one year. When the contact resistance was greater than 1Ω, the charging time of the energy storage capacitor 33 was extended by 50%, resulting in a 30% decrease in rectification efficiency.

[0050] 3. The natural frequency of the pendulum 44 cannot be completely consistent with the main vibration frequency band of the wind power, resulting in a mismatch. This causes the switching of the contact 43 to be reversed with the voltage polarity. For example, when the piezoelectric sheet 32 ​​outputs a positive voltage, the pendulum 44 fails to contact the corresponding contact 43 due to lag, causing this section of rectification to fail and affecting the charging effect of the energy storage capacitor 33.

[0051] To address these issues and further optimize energy harvesting performance, this application proposes Embodiment Four.

[0052] Example 4 like Figure 4 and 7 As shown in Comparative Embodiment 2, another embodiment of the present invention is as follows: the rectifier 4 further includes: Two steel balls 46 are slidably disposed in the cavity 42. The steel balls 46 are made of ferromagnetic material. The steel balls 46 are separately disposed from the contact 43 and fill the connection between the input end of the contact 43 and the positive electrode of the piezoelectric element 32, so that the contact 43 and the piezoelectric element 32 are connected in circuit. Two coils 47 are wound at both ends inside the cavity 42. The coils 47 form an excitation area. When the coils 47 are energized, they drive the steel balls 46 to move, causing the two sets of steel balls 46 and the contacts 43 to make alternating contact. The two ends of the coils 47 are respectively connected to the positive and negative poles of the piezoelectric sheet 32. A return spring 48 is used to move the steel ball 46 away from the contact 43.

[0053] Specifically, a 0.1mm gap is reserved between the steel ball 46 and the inner wall of the cavity 42 to allow for slight thermal expansion displacement and prevent structural jamming at high temperatures. The steel ball 46 is made of low-carbon steel, iron-nickel alloy, or other metals with strong magnetic adsorption capabilities, and is chrome-plated to reduce the coefficient of friction and improve wear resistance, adapting to the long-term high-frequency operation requirements of the device and ensuring smooth reciprocating motion. The two ends of the return spring 48 contact the steel ball 46 and the inner wall of the cavity 42, respectively. After the steel ball 46 moves to the left or right end, it simultaneously contacts the extension contact 6 and contact 43 on the same side, thus establishing circuit connection. Coil 47 is connected to piezoelectric element 32 via a rectifier bridge or diode to ensure unidirectional current flow and prevent short circuits. Coil 47 is made of enameled copper wire and is wound around the inner wall of cavity 42, close to both ends of cavity 42, forming two excitation zones. The piezoelectric voltage generates an alternating magnetic field in the excitation zones, driving steel ball 46. Return spring 48 is made of stainless steel wire and is located between the inner wall of cavity 42 and steel ball 46. When there is no magnetic field, it returns steel ball 46 to the center, preventing accidental contact of contact point 43. Coil 47 is directly wound around the inner wall of cavity 42, while steel ball 46 is located on an axial guide rail inside cavity 42. Steel ball 46 is within the winding area of ​​coil 47, and coil 47 encloses the movement space of steel ball 46. This design maximizes the utilization of the magnetic field: the magnetic field generated by coil 47 acts directly on steel ball 46, and the magnetic field strength is higher than that of the design where coil 47 and steel ball 46 are separated. This ensures that steel ball 46 can still be effectively driven when the piezoelectric output voltage is <5V under weak vibration, avoiding rectification failure and better meeting the requirements of low power consumption drive.

[0054] Forward voltage stage: Due to vibration deformation, the multi-stage cantilever piezoelectric element 32 outputs a positive alternating voltage, which is transmitted to the coil 47 through the wire. The positive voltage flows through the coil 47, generating an N-pole magnetic field in the left excitation zone and demagnetizing the right excitation zone. The N-pole magnetic field in the left excitation zone attracts the left steel ball 46 to move to the left and slide along the guide rail of the cavity 42 until it contacts the left contact 43. At the same time, the right steel ball 46 is kept in the middle under the action of the return spring 48 and does not contact the right contact 43. The positive current forms a loop through the left contact 43 → the positive terminal of the energy storage capacitor 33 → the negative terminal of the energy storage capacitor 33 → the common ground wire of the piezoelectric element 32, completing the rectification and storage of the positive half-cycle current.

[0055] Reverse voltage stage: Piezoelectric element 32 outputs reverse alternating voltage, and the current direction is reversed, flowing through coil 47; the reverse voltage causes the right excitation region of coil 47 to generate an S pole magnetic field, and the left excitation region to be demagnetized; the S pole magnetic field of the right excitation region attracts the right steel ball 46 to move to the right and contact the right contact 43; the left steel ball 46 is reset under the action of the reset spring 48 and disengages from the left contact 43; the reverse current forms a loop through the right contact 43 → positive terminal of energy storage capacitor 33 → negative terminal of energy storage capacitor 33 → common ground wire of piezoelectric element 32. Although the current polarity is reversed, because the contact 43 is fixedly connected to the positive terminal of the capacitor, the actual current still flows unidirectionally to the capacitor, completing the rectification and storage of the reverse half-cycle current.

[0056] Through the mechanical movement of the alternating contact between the double contacts 43 and the steel ball 46, the alternating current output by the piezoelectric is converted into a unidirectional pulsating current, which charges the energy storage capacitor 33, realizing a closed-loop self-powered system of energy capture-rectification-energy storage-power supply without the need for an external power source.

[0057] It should be noted that the mass of the steel ball 46, the magnetic field generated by the coil 47, and the force of the return spring 48 are selected according to the actual situation, so as to satisfy that "the magnetic field generated by the coil 47 can overcome the force of the return spring 48 and drive the steel ball 46 to move".

[0058] In another implementation, the vibration sensor 21 is powered by an independent battery, its ground wire is physically isolated from the common ground wire, and multiple sets of the piezoelectric elements 32 are connected in parallel.

[0059] Specifically, the vibration sensor 21 is powered by an independent 3.7V / 100mAh lithium battery, with a physical distance of ≥5mm between it and the energy harvesting unit 3 circuit to avoid affecting detection accuracy due to piezoelectric power fluctuations. It should be noted that, depending on the specific operating environment requirements, a lithium battery + solar auxiliary power supply solution can also be adopted, equipped with a charging management chip such as CN3052, to further ensure long-term stable power supply.

[0060] Multiple piezoelectric elements 32 are connected in parallel and input into a rectifier. The positive wires of all piezoelectric elements 32 are connected together to form a bus, and the negative wires of all piezoelectric elements 32 are connected together to form another bus. The two buses are connected to the energy harvesting unit 3 circuit, which can automatically collect the energy generated by all piezoelectric elements 32, realize energy superposition, and output a larger current. Moreover, each piezoelectric element 32 works independently and does not affect each other.

[0061] It should be noted that the parallel arrangement of piezoelectric elements 32 also includes methods such as rectifying each group of piezoelectric elements 32 independently before parallel connection, or adding diodes for isolation.

[0062] like Figure 4 and 7 As shown, the two steel balls 46 are located in the middle of the cavity 42, and the two coils 47 are an integrated wire structure, with the two coils 47 wound in opposite directions.

[0063] The steel ball 46 is initially located in the middle of the cavity 42 and moves only in one direction when driven by the magnetic field of the coil 47. The two contacts 43 will not be connected by the steel ball 46 at the same time. Therefore, there will be no situation where both contacts 43 are in contact with the steel ball 46 and a short circuit is formed. It can completely capture the energy of the positive and negative half cycles of the alternating current and avoid the energy waste of wiring with a single contact 43.

[0064] The two coils 47 are an integral structure formed by continuously winding the same enameled copper wire around the inner wall of the cavity 42. After the coils 47 are wound, the entire structure is fixed to the wall of the cavity 42 with insulating glue. Due to the difference in position between the left and right ends of the coils 47, they are naturally divided into a left excitation region and a right excitation region. This integrated coil 47 + dual excitation region design is to generate a magnetic field alternately at the left and right ends by changing the direction of the same current, rather than having the two coils 47 work separately. This avoids the cancellation of magnetic fields between the independent coils 47, reduces reliance on electronic components, simplifies the mechanical structure, and consumes no additional energy.

[0065] When current flows through a point where the magnetic field is strong at one end and weak at the other (equivalent demagnetization), the essence of this phenomenon is the superposition / cancellation effect of magnetic fields caused by opposite directions of flow. Forward current stage: Current flows in from the left excitation zone and out from the right excitation zone. Because the left and right directions are opposite, the magnetic field generated in the left zone is opposite to that in the right zone. The two cancel each other out in the middle of the cavity 42. However, the left zone is close to the left end, so the magnetic field is not completely canceled out, which is enough to attract the steel ball 46 at the left end. The right zone is far away from the steel ball 46 at the right end, so the magnetic field is completely canceled out and there is no driving force. Reverse current phase: The current direction reverses, the magnetic field in the right excitation zone is not completely canceled, attracting the right-end steel ball 46; the magnetic field in the left zone is canceled, and there is no driving force. This single-sided effective magnetic field design ensures that the steel ball 46 moves only in one direction, avoiding jamming caused by bidirectional forces.

[0066] This application, by setting up coil 47, utilizes a magnetic field to drive steel ball 46 to cooperate with contact 43, achieving the following functions: Non-contact energy conversion: Electromagnetic drive avoids mechanical wear, and steel ball 46 is only subjected to magnetic force, thus extending its lifespan. Deep synergy of vibration-energy-rectification: The multi-stage cantilever beam and steel ball 46 are mass-matched, and vibration energy directly drives rectification without the need for additional inertial mass, forming a closed loop of vibration energy harvesting → magnetic field drive → mechanical rectification, while saving the space required for installing pendulum rod 44.

[0067] Example 5 The detection device needs to be installed in the appropriate location and fixing method according to the different target monitoring components of the wind turbine. Taking the installation on the platform in the middle section of the tower as an example, the specific steps are as follows: Installation area pretreatment: First, the installation area of ​​the middle platform of the tower is pretreated: use a sandblasting tool to clean the outer wall of the tower, thoroughly remove rust, coating and impurities, expose the metal substrate, and ensure the fit of the subsequent expansion sleeve 5 with the outer wall of the tower to avoid vibration signal transmission attenuation. Non-damaging fixing of expansion sleeve 5: Insert the 45# steel expansion sleeve 5 into the pre-set installation hole of the tower. If there is no suitable existing maintenance hole, use a torque wrench to tighten the nuts at both ends of the expansion sleeve 5, so that the outer sleeve expands radially and forms an interference fit with the wall of the tower installation hole, so as to achieve non-damaging fixing of expansion sleeve 5 to the tower and avoid damage to the tower structure caused by traditional welding. The main body of the device is mounted and locked: the vibration detection unit 2, the energy harvesting unit 3, and the rectifier unit 4 are integrated on the base 1 to form the main body. The base 1 is slid along the T-shaped guide rail on the outer wall of the expansion sleeve 5 to the target installation position. The base 1 is equipped with locking and positioning devices to ensure the accurate installation position of the main body of the device. The base 1 is also equipped with a self-locking mechanism to mechanically lock the position of the base 1. The installation time of a single device is ≤3 minutes, which is convenient for on-site operation and maintenance personnel to deploy quickly.

[0068] If it needs to be installed on the drive chain or blade root, only the fixing position of the expansion sleeve 5 needs to be adjusted: When installing the drive chain, fix the expansion sleeve 5 to the outer wall of the bearing seat at the input / output end of the gearbox or the front and rear end covers of the generator; when installing the blade root, evenly arrange 3-4 expansion sleeves 5 and the main body of the device along the outer circumference of the bolt flange connecting the blade and the hub to ensure comprehensive acquisition of blade flapping / swaying vibration signals.

[0069] Working Principle: This device is installed on key parts of the tower and blades via a clamp structure. When the wind turbine is running, its gearbox, tower, and other components vibrate, and this vibration is transmitted to the device through the base 1. The vibration sensor 21 detects the vibration and outputs an analog signal. After filtering, amplification, and feature extraction by the processing module, the signal is transmitted to the external operation and maintenance system via the wireless communication module. Simultaneously, the vibration energy drives the multi-stage cantilever beam array 31 to undergo bending vibration, which is converted into alternating current by the piezoelectric element 32. The alternating current is converted into direct current by the rectifier 4 and stored in the energy storage capacitor 33 to power the vibration detection unit 2, achieving closed-loop self-sustaining operation of detection and power supply. This device requires no external power supply and is suitable for long-term, unattended vibration monitoring scenarios for wind turbines.

[0070] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A vibration detection device for wind turbine generators, comprising a base (1) disposed at the measured area of ​​the wind turbine generator, characterized in that: Also includes: The vibration detection unit (2) includes a vibration sensor (21) that collects vibration data of the wind turbine generator. The vibration detection unit (2) also includes a processing module and a communication module for processing the vibration data. The energy harvesting unit (3) includes a multi-stage cantilever beam array (31) and an energy storage capacitor (33). The multi-stage cantilever beam array (31) is provided with a piezoelectric sheet (32). The piezoelectric sheet (32) converts the mechanical vibration energy of the multi-stage cantilever beam array (31) into electrical energy and stores it in the energy storage capacitor (33) to power the vibration detection unit (2). The rectifier (4) is connected to the piezoelectric element (32) via a wire, and converts the alternating current output by the piezoelectric element (32) into a unidirectional current.

2. The wind turbine vibration detection device according to claim 1, characterized in that: The sensing surface of the vibration sensor (21) is rigidly connected to the base (1) and is perpendicular to the vibration direction of the wind turbine, with an error of no more than 5°.

3. The wind turbine vibration detection device according to claim 2, characterized in that: The multi-stage cantilever beam array (31) includes several cantilever beams of different lengths, each corresponding to a different resonance frequency, capturing different broadband vibration energies, and the several cantilever beams are evenly distributed in a ring.

4. The wind turbine vibration detection device according to claim 3, characterized in that: The energy harvesting unit (3) also includes: A mass block (34) is slidably disposed at the end of the cantilever beam, and the contact surface between the mass block (34) and the cantilever beam is provided with a damping structure: A positioning spring (35) is provided between the cantilever beam and the mass block (34).

5. The wind turbine vibration detection device according to claim 4, characterized in that: The energy harvesting unit (3) also includes: An installation groove (36) is formed on the cantilever beam; The piezoelectric sheet (32) is fixed in the mounting groove (36) by the clamping mechanism (37).

6. The wind turbine vibration detection device according to claim 5, characterized in that: The rectifier (4) includes: A sealed housing (41) with a cavity (42) inside. Two contacts (43) are respectively located at both ends of the cavity (42). The input ends of the two contacts (43) are connected to the positive electrode of the piezoelectric sheet (32), and the connection is controlled to open and close. The output ends of the two contacts (43) are connected to the positive electrode of the energy storage capacitor (33). The negative electrode of the energy storage capacitor (33) is connected to the negative electrode of the vibration detection unit (2) through a common ground wire. The negative electrode of the piezoelectric sheet (32) is connected to the common ground wire.

7. A wind turbine vibration detection device according to claim 6, characterized in that: The rectifier (4) further includes: A swing rod (44) disposed inside the housing (41) is swung, with the bottom end of the swing rod (44) inserted into the cavity (42); A connector (45) is provided at the bottom of the swing rod (44). The connector (45) is made of conductive material. After the swing rod (44) swings, the connector (45) alternately contacts the two contacts (43) to fill the connection between the input end of the contact (43) and the positive electrode of the piezoelectric sheet (32), so that the contact (43) and the piezoelectric sheet (32) are connected in circuit.

8. A wind turbine vibration detection device according to claim 7, characterized in that: The rectifier (4) further includes: Two steel balls (46) are slidably disposed in the cavity (42). The steel balls (46) are made of ferromagnetic material. The steel balls (46) are separately disposed from the contact (43) to fill the connection between the input end of the contact (43) and the positive electrode of the piezoelectric sheet (32), so that the contact (43) and the piezoelectric sheet (32) are connected in circuit. Two sets of coils (47) are wound inside the cavity (42) at both ends. The coils (47) form an excitation zone. When the coils (47) are energized, they drive the steel balls (46) to move, causing the two sets of steel balls (46) and the contacts (43) to make contact alternately. The two ends of the coils (47) are respectively connected to the positive and negative poles of the piezoelectric sheet (32). A return spring (48) is used to move the steel ball (46) away from the contact (43).

9. A wind turbine vibration detection device according to claim 8, characterized in that: The vibration sensor (21) is powered by an independent battery, and its ground wire is physically isolated from the common ground wire. Multiple sets of the piezoelectric elements (32) are connected in parallel.

10. A wind turbine vibration detection device according to claim 9, characterized in that: The two steel balls (46) are located in the middle of the cavity (42), and the two coils (47) are an integrated wire structure, with the two coils (47) wound in opposite directions.

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