A vortex-induced vibration type bladeless wind power generation device with a magnetic tuning structure and a control method thereof

Abstract

This invention discloses a bladeless wind turbine with a magnetically tuned structure and its control method, belonging to the field of wind power generation and distributed energy equipment technology. The device includes a power generation module and a power regulation module. The power generation module includes a vibration module and a stator coil assembly. The vibration module includes a flexible central shaft, a wind-receiving mast, a permanent magnet assembly, and a slider. The wind-receiving mast generates vortex-induced lateral vibration under wind flow, driving the permanent magnet assembly to cut the stator coil assembly to generate electricity. The power regulation module obtains the vortex shedding frequency based on the external wind speed and adjusts the slider position to change the equivalent cantilever length of the flexible central shaft, matching the natural frequency of the vibration module with the vortex shedding frequency to increase power generation. Furthermore, it generates a PWM signal through PI control to drive a DC-DC converter, achieving maximum power output and constant voltage power supply. This invention features good low-wind-speed adaptability and low operation and maintenance costs, making it suitable for distributed generation and microgrid scenarios.

Description

Technical Field

[0001] This invention belongs to the field of wind power generation and distributed energy equipment technology, specifically relating to a vortex-induced vibration bladeless wind power generation device with a magnetic tuning structure and its control method. Background Technology

[0002] Wind energy, as a clean and renewable energy source, has broad development prospects in both centralized and distributed applications. Existing distributed wind power generation equipment mainly uses bladed horizontal-axis or vertical-axis wind turbines. While these devices are technologically mature, they still present challenges in scenarios with limited land resources or high noise and safety requirements, such as large footprint, high operating noise, high starting wind speeds, numerous maintenance components, and insufficient environmental compatibility.

[0003] In recent years, bladeless wind power generation technology has attracted attention due to its simplified structure, absence of high-speed rotating blades, lower noise, and suitability for deployment in complex low-altitude wind fields. These devices typically utilize the Karman vortex street formed by fluid flowing around a cylinder to induce structural vibrations, which are then converted into electrical energy to generate electricity. However, existing bladeless wind power generation devices still have the following shortcomings: First, their frequency-locked operating range is narrow, making it difficult to adapt to random fluctuations in natural wind speeds, thus limiting the effective power generation wind speed range; second, they are difficult to start up under low wind speed conditions, resulting in insufficient utilization of wind energy at low wind speeds.

[0004] Therefore, there is an urgent need to propose a bladeless wind power generation device that can solve the above-mentioned technical problems. Summary of the Invention

[0005] To address the problems in the prior art, this invention provides a vortex-induced vibration bladeless wind power generation device with a magnetic tuning structure and its control method.

[0006] The technical solution of the present invention is as follows: In a first aspect, the present invention discloses a vortex-induced vibration bladeless wind power generation device with a magnetic tuning structure, including an upper base, a lower base, a power generation module and a power regulation module; the power generation module includes a vibration module and a stator coil assembly fixedly connected to the upper base, the vibration module including a flexible central shaft vertically mounted on the lower base, a wind-receiving mast fixedly connected to the flexible central shaft, a permanent magnet assembly capable of vibrating with the wind-receiving mast, and a slider, the slider being sleeved on the flexible central shaft below the wind-receiving mast, and transitionally engaging with the flexible central shaft and capable of moving up and down along the flexible central shaft; The wind-driven mast generates vortex-induced lateral vibration under the influence of the airflow, which in turn drives the permanent magnet assembly to vibrate synchronously. At this time, the magnetic field lines of the permanent magnet assembly alternately cut the stator coil assembly to generate alternating current, which is then output to the power regulation module. The stator coil assembly and the permanent magnet assembly constitute the power generation unit. The power regulation module includes a maximum power point tracking (MPPT) control unit and a DC-DC converter unit. The MPPT control unit is used to obtain the incoming wind speed from the outside in real time, obtain the vortex shedding frequency based on the wind speed, adjust the position of the slider to change the equivalent cantilever length of the flexible central axis, so that the natural frequency of the vibration module is equal to the vortex shedding frequency, thereby maximizing the power generation of the power generation unit. It is also used to convert the AC power into stable DC power, and perform PI control according to the voltage and current corresponding to the DC power to generate PWM signals for the power devices in the DC-DC converter unit, so that the power generation unit operates in the maximum power output state. The DC-DC converter unit is used to convert the stable DC power into constant DC power under the control of the PWM signal and output it to the outside.

[0007] Furthermore, the wind-receiving mast is a cylindrical body with a cross-section that gradually decreases from top to bottom, and the cylindrical body is a hollow structure with a closed bottom and an open top; the wind-receiving mast is fixed to the flexible central axis only at the lower end face; the wind-receiving mast is made of carbon fiber composite material or glass fiber composite material.

[0008] Furthermore, the permanent magnet assembly includes multiple annular permanent magnets, with adjacent annular permanent magnets forming magnetic attraction or magnetic repulsion pairings; wherein, all annular permanent magnets are fixed to the inner wall of the wind-receiving mast, or some annular permanent magnets are fixed to the inner wall of the wind-receiving mast, and the remaining permanent magnets are sleeved and fixed on a flexible central shaft, so that the permanent magnet assembly can follow the vibration of the wind-receiving mast. The stator coil assembly includes an upper stator coil and a lower stator coil connected in series in the vertical direction. The stator coil is arranged coaxially with the flexible central shaft. During the vibration of the wind-driven mast, the flexible central shaft does not contact the stator coil assembly and the two do not interfere with each other. During the vibration process, the permanent magnet assembly is always within the effective magnetic coupling range of the stator coil assembly.

[0009] Secondly, the present invention also discloses a power generation control method for the power generation device, comprising the following steps: 1) The maximum power point tracking control unit obtains the incoming wind speed from the outside in real time, and obtains the vortex shedding frequency based on the wind speed. Then, it adjusts the position of the slider to change the equivalent cantilever length of the flexible central shaft, and / or adjusts the position of the counterweight to change the equivalent mass of the vibration module, so that the natural frequency of the vibration module is equal to the vortex shedding frequency, thereby maximizing the power generation of the power generation unit. 2) The wind-driven mast generates vortex-induced lateral vibration under the influence of the wind flow, which in turn drives the permanent magnet assembly to vibrate synchronously. At this time, the magnetic field lines of the permanent magnet assembly alternately cut the stator coil assembly to generate alternating current, which is then output to the maximum power tracking control unit. 3) The maximum power point tracking control unit converts the AC power into stable DC power, and then performs PI control based on the voltage and current corresponding to the DC power to generate PWM signals for the power devices in the DC-DC converter unit, so that the power generation unit operates in the maximum power output state; then the DC-DC converter unit converts the stable DC power into constant DC power under the control of the PWM signal and outputs it to the outside; wherein, the PWM signal is used to control the on-time ratio of the power devices.

[0010] Furthermore, when the incoming wind speed is lower than the preset vibration threshold of the wind-receiving mast, the conduction time ratio of the power device is adjusted to the preset minimum value, the slider is adjusted to the position where the equivalent stiffness of the vibration module is minimized, and the counterweight is adjusted to the position where the equivalent mass of the vibration module is maximized. When the incoming wind speed exceeds the safe vibration threshold of the wind-receiving mast or when abnormal sudden changes in the output voltage or frequency of the power generation device are detected, the conduction time ratio of the power device is adjusted to the preset maximum value, the slider is adjusted to the position where the equivalent stiffness of the vibration module reaches the maximum, and the counterweight is adjusted to the position where the equivalent mass of the vibration module reaches the minimum.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: 1) The bladeless structure with vortex-induced vibration is adopted, eliminating high-speed rotating blades, which significantly reduces noise and environmental risks and improves the adaptability of deployment in parks, building perimeters and densely populated areas; 2) The present invention uses a wind-receiving mast, a flexible central shaft and a slider assembly (i.e., slider) and a counterweight assembly (i.e. counterweight block) to form an adjustable vibration body. By changing the position of the auxiliary constraint, the problem that the natural frequency of the existing bladeless wind power generation device is difficult to adjust with the wind speed is solved, thereby expanding the available wind speed range and improving the energy utilization efficiency under low wind speed and variable wind speed conditions. 3) This invention employs a permanent magnet assembly and a stator coil assembly to form a power generation unit. The maximum power point tracking control unit adjusts the conduction time ratio of the power devices in the DC-DC converter unit in real time, matching the electromagnetic damping of the power generation unit with the structural vibration state. This improves the conversion efficiency of mechanical energy to electrical energy and enhances output stability, even when the power generation unit operates at maximum power output. Furthermore, the gearless direct-drive power generation unit composed of the permanent magnet assembly and stator coil assembly reduces mechanical transmission links, lowering friction loss and maintenance costs. 4) The present invention simultaneously introduces wind speed closed-loop, maximum power point tracking and electromagnetic damping adjustment into the control method. Therefore, it can assist in vibration in the low wind speed stage, maintain frequency matching in the variable wind speed stage, and limit amplitude in a timely manner under abnormal operating conditions, thus taking into account both power generation efficiency and structural safety. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the overall structure of the vortex-induced vibration bladeless wind power generation device of the present invention. Figure 2 This is a cross-sectional view of the mechanical structure and key components of the vortex-induced vibration bladeless wind power generation device of the present invention. Figure 3 This is an overall perspective view of the vortex-induced vibration bladeless wind power generation device of the present invention. Figure 4 This is a schematic diagram of the control structure for generating PWM signals for power devices in a DC-DC converter unit using a voltage tracking control circuit, as described in this invention. Detailed Implementation

[0013] The present invention will be further described and illustrated below with reference to specific embodiments. The embodiments described are merely examples of the content of this disclosure and do not limit the scope of the invention. The technical features of each embodiment in the present invention can be combined accordingly, provided that there is no mutual conflict.

[0014] The purpose of this invention is to address the problems of narrow frequency locking range and insufficient low-wind-speed vibration start-up capability in existing bladeless wind power generation devices, and to provide a vortex-induced vibration bladeless wind power generation device with a magnetic tuning structure and its control method. This invention has the advantages of small footprint, low noise, simplified structure, strong adaptability to low wind speeds, low operation and maintenance costs, and suitability for deployment in gap wind farms such as parks, building perimeters, and road wind corridors. It can be used in distributed generation and microgrid scenarios.

[0015] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0016] like Figure 1 and Figure 2 As shown, the vortex-induced vibration bladeless wind power generation device with magnetic tuning structure of the present invention includes a base, an external support, a flexible central shaft, a wind-receiving mast, a counterweight assembly, a slider assembly, a power generation unit, and a power regulation module. The base includes an upper base and a lower base, and the external support is disposed between the upper base and the lower base and fixedly connected to the upper base and the lower base. The flexible central shaft, the wind-receiving mast, the counterweight assembly, the slider assembly, and the power generation unit constitute the power generation module.

[0017] Regarding the spatial positions of each component, in one embodiment, the wind-receiving mast is vertically positioned at the top of the device, and the flexible central shaft is vertically installed at the center of the lower base and fixedly connected to the wind-receiving mast. Together, they constitute the main vibrating component and do not undergo relative movement or rotation. The external support is independently configured from the flexible central shaft and the wind-receiving mast. The power generation unit is located in the central region of the flexible central shaft and includes a moving permanent magnet assembly and a fixed stator coil assembly. The moving permanent magnet assembly is fixedly connected to the inner wall of the wind-receiving mast and moves synchronously with the vibration of the wind-receiving mast. The stator coil assembly is fixedly connected to the upper base via hooks and remains stationary.

[0018] The base provides overall support and anti-overturning capacity, and serves as the mounting foundation for the external support, flexible central shaft, and power generation unit. The external support is mounted on the base and forms a static frame independent of the vibrating components. The flexible central shaft is vertically positioned in the middle of the lower base, with its lower portion (approximately one-third from bottom to top) fixedly connected to the solid part of the wind-receiving mast (i.e., the lower end of the wind-receiving mast). A retaining spring is used to limit and position the wind-receiving mast, ensuring a rigid connection between the flexible central shaft and the mast. A slider assembly is fitted onto the flexible central shaft below the connection point between the wind-receiving mast and the flexible central shaft, and can move up and down along the flexible central shaft. A counterweight assembly is mounted on the flexible central shaft above the connection point between the wind-receiving mast and the flexible central shaft, and can move up and down along the flexible central shaft. The wind-receiving mast is located within the external support and serves as... The main components are subject to wind vibration. The power generation unit is located between the flexible central shaft and the wind-receiving mast. The radial direction of the stator coil assembly is consistent with the radial direction of the flexible central shaft, and the permanent magnet assembly and the stator coil assembly are arranged opposite each other along the radial direction of the stator coil assembly. The stator coil assembly is fixedly connected to the upper base via hooks and does not contact or interfere with the flexible central shaft, the wind-receiving mast, or the permanent magnet assembly during movement. The stator coil assembly includes an upper stator coil and a lower stator coil connected in series in the vertical direction. The radial directions of both the upper and lower stator coils are consistent with the radial direction of the flexible central shaft. Therefore, in terms of dimensional relationships, the inner diameter of the stator coil... The outer diameter is greater than the maximum outer diameter of the flexible central shaft under the maximum vibration displacement envelope, and a radial safety clearance δ of not less than 5 mm is reserved between the two. ,in The equivalent cantilever length is the flexible central axis. This refers to the deflection angle of the flexible central axis, specifically the angle of deflection from the constrained position of the slider assembly. This is the deflection angle during normal operation of this device. The typical angle is 5° to 10°. This device is not intended for use in severe weather conditions such as typhoons; therefore, angles exceeding this range are not considered. In the event of natural disasters, a protective cover should be used to protect the wind power generation device, or the device should be moved indoors. The vibration module consists of a flexible central shaft, a wind-receiving mast, a counterweight assembly, a slider assembly, and a permanent magnet assembly.

[0019] The wind-receiving mast is preferably made of carbon fiber composite material and can be an inverted frustum or other slender member with a cross-section that varies along the height direction. In a preferred embodiment of the invention, the wind-receiving mast is a cylindrical body with a cross-section that gradually decreases from top to bottom, and the cylindrical body is a hollow structure with a closed bottom and an open top.

[0020] The flexible central shaft, wind-receiving mast, and stator coil assembly preferably meet functional matching requirements in the vertical direction, but are not limited to a fixed length ratio. Specifically, the wind-receiving mast is located at the top of the device and forms the main wind-receiving vibration section; the flexible central shaft is fixedly connected to the wind-receiving mast and provides elastic deformation capability; the stator coil assembly consists of multiple coils connected in series, and is located in the corresponding area of ​​the power generation unit to ensure that the permanent magnet assembly remains within the effective magnetic coupling range of the coils during vibration, while avoiding interference between the stator coil assembly and other moving parts. Therefore, the vertical length and installation position of the three components should be comprehensively determined based on the vibration stroke, power generation requirements, and structural layout. The flexible central shaft may not pass through the stator coil assembly, but a longer central shaft usually increases the overall flexibility, making frequency modulation and vibration response more pronounced. If it does not pass through, the formula for calculating the inner diameter of the coil mentioned above can be ignored, and the inner diameter of the stator coil assembly is not strictly limited in this case.

[0021] Because the airflow forms alternating Kármán vortex streets on the leeward side of the mast after bypassing it (Kármán vortex streets refer to the alternating vortex sequences arranged in two staggered rows on the leeward side of a cylindrical, frustum-shaped, or other non-streamlined columnar structure when uniform airflow bypasses it), the mast experiences lateral vibration within a specific wind speed range. By designing the top diameter, bottom diameter, height, and mass distribution of the mast, the matching relationship between the natural frequency of its vibration module and the vortex shedding frequency of the Kármán vortex street can be adjusted, thereby improving the frequency locking range and resonance response. The vortex shedding frequency can be expressed as: in, The vortex shedding frequency; For incoming air velocity; These are Strauhal numbers; This represents the average diameter of the wind-receiving mast.

[0022] To achieve higher energy capture efficiency, it is preferable to set the natural frequency of the vibration module. With the vortex shedding frequency The following relationship must be satisfied: in, The equivalent stiffness of the fixed components involved in the vibration includes a flexible central shaft, a wind-receiving mast, a counterweight assembly, a slider assembly, and a permanent magnet assembly. The equivalent mass of the fixed components involved in the vibration is the sum of the masses of the flexible central shaft, the wind-receiving mast, the counterweight assembly, the slider assembly, and the permanent magnet assembly.

[0023] The flexible central shaft is fixedly connected to the lower base to form an elastic constraint system. The flexible central shaft transmits the vibrational displacement of the wind-receiving mast and allows the mast to sway or rotate during lateral vibrations. This invention adjusts the natural frequency by adjusting the positions of the counterweight assembly and the slider assembly. The bladeless wind power generation device of the present invention also includes a guide structure for vertically guiding and limiting the slider assembly, such as... Figure 1 As shown. The slider assembly slides into the guide structure and contacts or clearance-fits the flexible central shaft; by adjusting the position of the slider assembly along the height direction, the equivalent cantilever length of the flexible central shaft can be changed, thereby altering the natural frequency of the vibration module. To adapt to the average wind speed in different deployment environments (i.e., to adapt to the vortex shedding frequency) The slider assembly can be automatically adjusted using methods such as lead screw drive or linear motor drive.

[0024] Regarding the adjustment of the natural frequency of the vibration module, the mechanical structure mainly utilizes a counterweight assembly and a slider assembly. Both components can be used to adjust the natural frequency and can be used together or adjusted independently. The counterweight assembly is used to adjust the equivalent mass involved in the vibration. Specifically, by changing the axial installation height of the counterweight assembly on the flexible central shaft, the mass distribution and moment of inertia of the fixed components involved in the vibration can be altered, thereby changing the equivalent mass of the fixed components involved in the vibration and achieving the adjustment of the natural frequency of the vibration module. The counterweight assembly is located above the connection between the bottom of the wind-receiving mast and the flexible central shaft, and is fitted onto the flexible central shaft. A through hole is provided vertically at the center of the counterweight assembly to allow the flexible central shaft to pass through. The counterweight assembly and the flexible central shaft are fitted together, and the lower end of the counterweight assembly is secured by an elastic retaining ring to ensure that it does not fall down.

[0025] The slider assembly is located at the lower part of the flexible central axis and can be guided by a guide structure to move up and down along the flexible central axis, thereby changing the constrained position of the flexible central axis and thus changing the equivalent cantilever length of the flexible central axis. For a vibration module that is equivalent to a cantilever beam, the equivalent stiffness of its fixed components (i.e., the vibration module) participating in the vibration is... Equivalent cantilever length relative to the flexible central axis Inversely proportional, the best option satisfies ,in The elastic modulus of the material used to manufacture the flexible central shaft, Let be the moment of inertia of the cross section of the flexible central axis. Therefore, when the slider assembly moves downward along the flexible central axis, the equivalent cantilever length of the flexible central axis is... When increased, the equivalent stiffness of the vibration module Decrease, thereby reducing the natural frequency Lower it; conversely, the same applies. When the wind speed is low, the natural frequency of the vibration module needs to be lowered. Therefore, it is necessary to move the slider assembly downwards along the flexible central axis and / or adjust the counterweight assembly upwards along the flexible central axis. Moving the counterweight assembly upwards along the flexible central axis increases the equivalent mass of the vibration module. The movement method can be controlled by a controller based on the vortex shedding frequency determined by the externally acquired wind speed. Then, the slider assembly is moved downwards and / or the counterweight assembly is moved upwards using methods such as lead screw drive or linear motor drive, until the vortex falls off at a certain frequency. With natural frequency The amplitudes are nearly equal, meaning the wind-exposed mast reaches its maximum amplitude response under the Kármán vortex street effect. Similarly, when the wind speed is high, the natural frequency of the vibration module needs to be increased. The slider assembly is moved upward along the flexible central axis and / or the counterweight assembly is adjusted to move downward along the flexible central axis. In the initial state, the slider assembly is located in the middle of the guide structure or at a preset reference position, and the reference installation position of the counterweight assembly is located at the upper part of the part that is fixed between the flexible central axis and the bottom of the mast.

[0026] The slider assembly is mainly used to adjust the equivalent stiffness of the vibration module by changing the equivalent cantilever length of the flexible central shaft, and belongs to the coarse adjustment mechanism for frequency regulation; adjusting the counterweight assembly to adjust the equivalent mass of the vibration module belongs to the fine adjustment mechanism for frequency regulation. Preferably, the slider assembly is adjusted first, and after the slider assembly is adjusted to the target range, the vertical position of the counterweight assembly is adjusted for fine adjustment, so that the natural frequency of the vibration module is closer to the actual vortex shedding frequency.

[0027] The outer diameter of the counterweight assembly is smaller than the inner diameter of the stator coil and the minimum passage inner diameter within the stator coil installation area, and the counterweight assembly cannot enter the stator coil and cause mechanical interference. Preferably, the counterweight assembly is made of a metallic material, such as steel, copper, tungsten alloy, or a combination thereof; the slider assembly can be made of wear-resistant engineering plastics, aluminum alloy, or steel to balance guiding accuracy, wear resistance, and structural strength.

[0028] The permanent magnet assembly comprises multiple ring-shaped permanent magnets. All of these ring-shaped permanent magnets can be fixed to the windward mast, or a portion can be fixed to the mast while the rest are rigidly connected to a flexible central shaft. The connection method is the same as for the counterweight assembly: a central opening allows the flexible central shaft to pass through, providing a smooth transition fit, and a retaining spring for vertical positioning. Adjacent ring-shaped permanent magnets can form magnetic attraction or magnetic repulsion pairs: magnetic repulsion pairs provide additional negative stiffness during small vibration displacement stages, helping to lower the vibration threshold; magnetic attraction pairs provide greater restoring force as vibration displacement increases, helping to suppress excessive amplitude and improve structural stability.

[0029] The wind-driven mast generates vortex-induced lateral vibration under the influence of the airflow, which in turn drives the permanent magnet assembly to vibrate synchronously. At this time, the magnetic field lines of the permanent magnet assembly alternately cut the stator coil assembly, generating an alternating electromotive force in the stator coil assembly, thereby outputting low-frequency alternating current to the power regulation module.

[0030] The power regulation module is electrically connected to the power generation unit and includes a rectifier unit, a filter unit, a voltage tracking control circuit, a DC-DC converter unit, and a controller, wherein the DC-DC converter unit is mapped to a variable load unit.

[0031] The controller acquires wind speed from the outside in real time, determines the vortex shedding frequency based on the wind speed, and then adjusts the position of the slider assembly to change the equivalent cantilever length of the flexible central axis. This ensures that the natural frequency of the vibration module is equal to the vortex shedding frequency, maximizing the power generation of the power generation module. The rectifier unit converts the low-frequency AC output from the power generation unit into pulsating DC; the filter unit smooths the voltage ripple of the pulsating DC and outputs a stable DC. Figure 4 As shown, the voltage tracking control circuit performs PI control based on the voltage and current corresponding to the stable DC current, generating a PWM signal for the power devices in the DC-DC converter unit. The DC-DC converter unit, under the control of the PWM signal, converts the stable DC current into a constant DC voltage and outputs it externally. In one embodiment of the invention, the voltage tracking control circuit acquires the voltage corresponding to the stable DC current. and current, and voltage reference value obtained based on MPPT algorithm. Then the voltage reference value With voltage Subtract the current and input the result to the PI controller for PI control, obtain the PWM signal of the power device in the DC-DC converter unit and output it to the power device.

[0032] like Figure 4 As shown, the DC-DC converter unit consists of capacitors connected in parallel. It consists of a boost converter circuit, which includes an inductor. ,diode ,capacitance ,resistance and power devices ,inductance One end is connected to the capacitor The connection, inductance The other end is connected to the diode. Positive electrode and power devices The collectors of the diodes are connected. The negative terminals are respectively connected to the capacitor one end and resistor One end is connected, power device emitter, capacitor The other end, capacitor The other end and resistor The other ends are connected to each other. Power devices The gate is used to receive PWM signals, which are PWM duty cycle signals used in power devices. The proportion of conduction time.

[0033] Regarding the control method, the controller preferably employs the perturbation-observation method or the incremental conductance method to perform maximum power point tracking. That is, in this embodiment, the voltage reference value obtained based on the MPPT algorithm is obtained using the perturbation-observation method or the incremental conductance method. During device operation, the controller continuously corrects the voltage reference value according to the current output power change trend. This ensures that the electromagnetic damping of the power generation unit matches the current wind speed conditions.

[0034] At voltage reference value During the adjustment process, the controller calculates the current output power P based on the output voltage U and output current I of the power generation unit. The disturbance observation method is preferably used to execute the voltage reference value. Tracking: The controller acquires the output power of two adjacent outputs at a preset sampling period. If the current output power is greater than the other output power (i.e., the output power increases), the current voltage reference value plus a preset change range is used as the new voltage reference value. If the current output power is less than the other output power (i.e., the output power decreases), the current voltage reference value minus the preset change range is used as the new voltage reference value. If the current output power is equal to the other output power (i.e., the output power remains unchanged), the current voltage reference value is used as the new voltage reference value.

[0035] Besides the perturbation observation method, the incremental conductance method can also be used for maximum power point tracking. When using the incremental conductance method, the controller acquires voltage and current increments at a preset sampling period and calculates the incremental conductance based on these increments. Simultaneously, the controller obtains the instantaneous conductance at the current moment based on the voltage and current corresponding to the current DC current. The incremental conductance is compared with the instantaneous conductance at the current moment. If the incremental conductance is greater than the negative instantaneous conductance, the current operating point is determined to be to the left of the maximum power point, and the voltage reference value needs to be increased; that is, the current voltage reference value plus a preset change amplitude is used as the new voltage reference value. If the incremental conductance is less than the negative instantaneous conductance, the current operating point is determined to be to the right of the maximum power point, and the voltage reference value needs to be decreased; the current voltage reference value minus the preset change amplitude is used as the new voltage reference value. If the incremental conductance equals the negative instantaneous conductance, the current operating point is determined to have reached the maximum power point, and the voltage reference value remains unchanged; the current voltage reference value is used as the new voltage reference value, ensuring that the electromagnetic damping of the power generation unit matches the current structural vibration state. The above method can be used to match the electromagnetic damping of the power generation unit with the current structural vibration state.

[0036] During the low wind speed start-up phase, when the detected incoming wind speed is close to or slightly below the preset oscillation threshold, the controller adjusts the PWM duty cycle signal to the minimum to reduce the suppression effect of electromagnetic damping on oscillation; at the same time, it moves the slider assembly down to a low stiffness position to help the device enter a stable vibration state.

[0037] During the high wind speed protection phase, when the incoming wind speed is detected to be higher than the safety threshold, or when there is an abnormal sudden change in the output voltage or output frequency, the controller triggers the protection mode. It increases the electromagnetic damping by increasing the PWM duty cycle signal, and at the same time adjusts the slider assembly to the amplitude limiting position to suppress further increase in amplitude and reduce the risk of structural fatigue.

[0038] In one embodiment of the present invention, the present invention also provides a power generation control method using the power generation device, comprising the following steps: 1) The controller obtains the incoming wind speed from the outside in real time, and obtains the vortex shedding frequency based on the wind speed. Then, it adjusts the position of the slider to change the equivalent cantilever length of the flexible central shaft, and / or adjusts the position of the counterweight to change the equivalent mass of the vibration module, so that the natural frequency of the vibration module is equal to the vortex shedding frequency, thereby maximizing the power generation of the power generation unit. 2) The wind-driven mast generates vortex-induced lateral vibration under the influence of the wind flow, which drives the permanent magnet assembly to vibrate synchronously. At this time, the magnetic field lines of the permanent magnet assembly alternately cut the stator coil assembly to generate alternating current, which is then output to the rectifier unit. 3) The rectifier unit converts the AC power output from the generator unit into pulsating DC power. Then, the filter unit converts the pulsating DC power into stable DC power. Next, the voltage tracking control circuit performs PI control based on the voltage and current corresponding to the DC power to generate PWM signals for the power devices in the DC-DC converter unit, so that the generator unit operates in the maximum power output state. Then, under the control of the PWM signal, the DC-DC converter unit converts the stable DC power into constant DC power and outputs it to the outside. The PWM signal is used to control the on-time ratio of the power devices.

[0039] In one embodiment of the present invention, in step 3), a voltage reference value is obtained based on the MPPT algorithm, and then the voltage reference value is subtracted from the voltage corresponding to the DC current. The subtraction result and the current corresponding to the DC current are input to the PI controller for PI control to obtain the PWM signal of the power device in the DC-DC converter unit; wherein, the initial value of the voltage reference value is preset.

[0040] In one embodiment of the present invention, the voltage reference value obtained based on the MPPT algorithm is obtained based on the perturbation observation method or the conductance increment method.

[0041] Obtaining a voltage reference value based on the perturbation observation method includes: acquiring the output power corresponding to adjacent DC currents at a preset sampling period; if the output power increases, the current voltage reference value plus a preset change amplitude is used as the new voltage reference value; if the output power decreases, the current voltage reference value minus the preset change amplitude is used as the new voltage reference value; if the output power remains unchanged, the current voltage reference value is used as the new voltage reference value. Obtaining a voltage reference value based on the incremental conductance method includes: acquiring voltage and current increments at a preset sampling period, calculating the incremental conductance based on the voltage and current increments, and then acquiring the instantaneous conductance at the current moment; if the incremental conductance is greater than a negative instantaneous conductance, the current voltage reference value plus a preset change amplitude is used as the new voltage reference value; if the incremental conductance is less than a negative instantaneous conductance, the current voltage reference value minus the preset change amplitude is used as the new voltage reference value; if the incremental conductance is equal to a negative instantaneous conductance, the current voltage reference value is used as the new voltage reference value.

[0042] The device of this invention can be deployed as a distributed wind power generation unit on both sides of park roads, wind corridors between buildings, the edge of factory roofs, and other areas where traditional blade wind turbines are difficult to install. At the application level, the power output of the power generation device of this invention can be rectified and stabilized before being connected to external DC loads, and can be used in conjunction with photovoltaic systems, energy storage systems, and microgrid control systems to form a multi-energy complementary distributed energy supply solution.

[0043] This invention provides a bladeless wind turbine with a magnetically tuned vortex-induced vibration structure. By altering the equivalent stiffness and natural frequency of the vibration module through a slider assembly and adjusting the electromagnetic damping of the power generation unit through a power regulation module, the invention improves the low-wind-speed start-up capability, frequency locking capability under varying wind speeds, and output stability. The invention also provides a control method for the aforementioned device. Through closed-loop coordination of real-time wind speed acquisition, structural tuning, and the conduction time ratio of power devices, the vortex shedding frequency is kept close to the natural frequency of the vibration module, thereby improving vibration energy capture efficiency and power generation efficiency.

[0044] The above-described embodiments are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. Those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A bladeless wind power generation device with a magnetic tuning structure and vortex-induced vibration, characterized in that, It includes an upper base, a lower base, a power generation module, a maximum power point tracking control unit, and a DC-DC conversion unit; the power generation module includes a vibration module and a stator coil assembly fixedly connected to the upper base. The vibration module includes a flexible central shaft vertically mounted on the lower base, a wind-receiving mast fixedly connected to the flexible central shaft, a permanent magnet assembly capable of following the vibration of the wind-receiving mast, and a slider. The slider is sleeved on the flexible central shaft below the wind-receiving mast, and transitionally engages with the flexible central shaft and can move up and down along the flexible central shaft. The wind-driven mast generates vortex-induced lateral vibration under the influence of the airflow, which in turn drives the permanent magnet assembly to vibrate synchronously. At this time, the magnetic field lines of the permanent magnet assembly alternately cut the stator coil assembly to generate alternating current, which is then output to the maximum power tracking control unit. The stator coil assembly and the permanent magnet assembly constitute the power generation unit. The maximum power point tracking control unit is used to obtain the incoming wind speed from the outside in real time, obtain the vortex shedding frequency based on the wind speed, adjust the position of the slider to change the equivalent cantilever length of the flexible central shaft, so that the natural frequency of the vibration module is equal to the vortex shedding frequency, thereby maximizing the power generation of the power generation unit; and is used to convert the AC power into stable DC power, and perform PI control according to the voltage and current corresponding to the DC power to generate PWM signals for the power devices in the DC-DC converter unit, so that the power generation unit operates in the maximum power output state; the DC-DC converter unit is used to convert the stable DC power into constant DC power under the control of the PWM signal and output it to the outside.

2. The vortex-induced vibration bladeless wind power generation device according to claim 1, characterized in that, The wind-receiving mast is a cylindrical body with a cross-section that gradually decreases from top to bottom, and the cylindrical body is a hollow structure with a closed bottom and an open top; the wind-receiving mast is fixed to the flexible central axis only at the lower end face; the wind-receiving mast is made of carbon fiber composite material or glass fiber composite material.

3. The vortex-induced vibration bladeless wind power generation device according to claim 1, characterized in that, The device also includes an external bracket fixed between the upper and lower bases and a guide structure for vertically guiding and limiting the slider assembly.

4. The vortex-induced vibration type bladeless wind power generation device according to claim 1, characterized in that, The permanent magnet assembly includes multiple annular permanent magnets, with adjacent annular permanent magnets forming magnetic attraction or magnetic repulsion pairings; wherein, all annular permanent magnets are fixed to the inner wall of the wind-receiving mast, or some annular permanent magnets are fixed to the inner wall of the wind-receiving mast, and the remaining permanent magnets are sleeved and fixed on a flexible central shaft, so that the permanent magnet assembly can follow the vibration of the wind-receiving mast. The stator coil assembly includes an upper stator coil and a lower stator coil connected in series in the vertical direction. The stator coil is arranged coaxially with the flexible central shaft. During the vibration of the wind-driven mast, the flexible central shaft does not contact the stator coil assembly and the two do not interfere with each other. During the vibration process, the permanent magnet assembly is always within the effective magnetic coupling range of the stator coil assembly.

5. The vortex-induced vibration bladeless wind power generation device according to claim 4, characterized in that, The flexible central shaft may or may not pass through the stator coil assembly. When the flexible central shaft passes through the stator coil assembly, the inner diameter of the stator coil of the stator coil assembly is greater than or equal to the equivalent cantilever length of the flexible central shaft multiplied by the sine of the deflection angle of the flexible central shaft plus a preset radial safety gap.

6. The vortex-induced vibration bladeless wind power generation device according to claim 2, characterized in that, The vibration module also includes a counterweight, which is located on the flexible central axis above the connection point between the wind-receiving mast and the central axis of the flexible rod. The counterweight is in transition with the flexible central axis and can move up and down along the flexible central axis. By moving the counterweight, the equivalent mass of the vibration module can be changed, thereby changing the natural frequency of the vibration module. Moving the counterweight upward will increase the equivalent mass of the vibration module. Natural frequency The calculation formula is: ； in, This represents the equivalent stiffness of the vibration module. The equivalent mass of the vibration module; Moving the slider upwards reduces the equivalent cantilever length of the flexible central shaft, thereby increasing the equivalent stiffness of the vibration module.

7. A power generation control method using the power generation device of claim 6, characterized in that, Includes the following steps: 1) The maximum power point tracking control unit obtains the incoming wind speed from the outside in real time, and obtains the vortex shedding frequency based on the wind speed. Then, it adjusts the position of the slider to change the equivalent cantilever length of the flexible central shaft, and / or adjusts the position of the counterweight to change the equivalent mass of the vibration module, so that the natural frequency of the vibration module is equal to the vortex shedding frequency, thereby maximizing the power generation of the power generation unit. 2) The wind-driven mast generates vortex-induced lateral vibration under the influence of the wind flow, which in turn drives the permanent magnet assembly to vibrate synchronously. At this time, the magnetic field lines of the permanent magnet assembly alternately cut the stator coil assembly to generate alternating current, which is then output to the maximum power tracking control unit. 3) The maximum power point tracking control unit converts the AC power into stable DC power, and then performs PI control based on the voltage and current corresponding to the DC power to generate PWM signals for the power devices in the DC-DC converter unit, so that the power generation unit operates in the maximum power output state; then the DC-DC converter unit converts the stable DC power into constant DC power under the control of the PWM signal and outputs it to the outside; wherein, the PWM signal is used to control the on-time ratio of the power devices.

8. The power generation control method according to claim 7, characterized in that, In step 3), generating the PWM signal for the power devices in the DC-DC converter unit includes: The voltage reference value is obtained based on the MPPT algorithm. Then, the voltage reference value is subtracted from the voltage corresponding to the DC current. The subtraction result and the current corresponding to the DC current are input to the PI controller for PI control to obtain the PWM signal of the power device in the DC-DC converter unit. The initial value of the voltage reference value is preset.

9. The power generation control method according to claim 8, characterized in that, The voltage reference value obtained based on the MPPT algorithm is obtained based on the perturbation observation method or the incremental conductance method. Voltage reference values ​​are obtained based on the perturbation observation method, including: The output power corresponding to adjacent DC currents is obtained at a preset sampling period. If the output power increases, the current voltage reference value plus a preset change amplitude is used as the new voltage reference value; if the output power decreases, the current voltage reference value minus the preset change amplitude is used as the new voltage reference value; if the output power remains unchanged, the current voltage reference value is used as the new voltage reference value; the voltage reference value is obtained based on the incremental conductance method, including: The voltage and current increments are acquired at a preset sampling period, and the incremental conductance is calculated based on the voltage and current increments. Then, the instantaneous conductance at the current moment is acquired. If the incremental conductance is greater than the negative instantaneous conductance, the result of adding the preset change amplitude to the current voltage reference value is used as the new voltage reference value. If the incremental conductance is less than the negative instantaneous conductance, the result of subtracting the preset change amplitude from the current voltage reference value is used as the new voltage reference value. If the incremental conductance is equal to the negative instantaneous conductance, the current voltage reference value is used as the new voltage reference value.

10. The power generation control method according to claim 7, characterized in that, When the incoming wind speed is lower than the preset vibration threshold of the wind-receiving mast, the conduction time ratio of the power device is adjusted to the preset minimum value, the slider is adjusted to the position where the equivalent stiffness of the vibration module is minimized, and the counterweight is adjusted to the position where the equivalent mass of the vibration module is maximized. When the incoming wind speed exceeds the safe vibration threshold of the wind-receiving mast or when abnormal sudden changes in the output voltage or frequency of the power generation device are detected, the conduction time ratio of the power device is adjusted to the preset maximum value, the slider is adjusted to the position where the equivalent stiffness of the vibration module reaches the maximum, and the counterweight is adjusted to the position where the equivalent mass of the vibration module reaches the minimum.

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