Double-end synchronous telescopic variable cross-section blade device of vertical axis wind turbine and control method thereof

Abstract

The invention discloses a double-end synchronous telescopic variable cross-section blade device of a vertical axis wind turbine and a control method of the double-end synchronous telescopic variable cross-section blade device, and belongs to the technical field of vertical axis wind turbines. Comprising a thick wing type bearing main body, a thin wing type telescopic blade section, a vertical axis wind turbine rotating shaft, an executing mechanism, a transmission mechanism, a locking positioning structure, a guiding and lapping structure, a wind speed detection module, a rotating speed detection module and a control unit. According to the H-shaped VAWT, the thin wing type telescopic blade sections which are symmetrically arranged are controlled to stretch out and draw back synchronously, the technical effect that the risks of mass center deviation and dynamic unbalance caused by mass distribution changes in the blade stretching-out and drawing-back process are reduced is achieved, and therefore the operation stability and reliability of the H-shaped VAWT under the rotating working condition are improved.

Description

Technical Field

[0001] This application belongs to the field of vertical axis wind turbine technology, specifically relating to a device for a double-end synchronous telescopic variable cross-section blade for an H-type vertical axis wind turbine and its control method. Background Technology

[0002] Wind turbines, as core equipment for converting wind energy into mechanical energy, occupy an important position in the field of new energy utilization. Among them, vertical axis wind turbines (VAWT) have shown broad application prospects in urban building environments with variable wind direction and high requirements for safety and aesthetics, as well as in distributed off-grid scenarios where installation and maintenance are inconvenient, due to their outstanding advantages such as strong versatility in wind reception, simple structure and manufacturing process, and wide range of wind speed and conditions.

[0003] Among various types of VAWTs, considering both their potential for large-scale development and overall operational performance, the straight-blade H-type VAWT is generally considered to be the most promising type. The core aerodynamic design of this type of wind turbine focuses on the matching of airfoil thickness and tip speed ratio (TSR, the dimensionless ratio of the wind turbine blade linear velocity to the incoming wind speed): thick airfoils have excellent flow adhesion capabilities, effectively suppressing dynamic stall and improving start-up performance and operational stability in the low to medium tip speed ratio range; while thin airfoils reduce the interaction between vortices through rapid vortex shedding in the high tip speed ratio range, which helps to improve flow separation on the blade surface, thereby improving lift-to-drag ratio and power output efficiency.

[0004] However, existing H-type VAWT blade designs still have significant limitations, making it difficult to meet the requirements for efficient and stable operation under a wide range of operating conditions. On the one hand, most designs adopt a single fixed airfoil or blade structure with a fixed thickness distribution. This design cannot simultaneously achieve anti-stall capability under low TSR conditions and high efficiency under high TSR conditions, resulting in a narrow applicable operating range for the wind turbine. In scenarios with frequent wind speed changes or large TSR ranges, it is prone to problems such as low aerodynamic efficiency and severe output fluctuations. For example, the lift-type VAWT with partially swept blades proposed in Chinese utility model patent CN209621520U, although improving some aerodynamic characteristics under complex wind conditions through local geometric optimization, still cannot achieve synergistic optimization for low and high TSR conditions due to the fixed blade geometry, making it difficult to cover the requirements of full-condition operation.

[0005] On the other hand, a few existing technologies disclose retractable wind turbine blade designs, attempting to adapt to different operating conditions by changing the blade shape. For example, Chinese invention patent CN113653591A discloses a retractable wind turbine blade with electrothermal anti-icing function. The retractable blade is installed inside the main blade by a sleeve sliding method, and the retraction is driven by an electric motor to change the blade length. Its core design goal focuses on electrothermal anti-icing and retraction, but does not provide a systematic solution for the rotational operating characteristics of H-type VAWTs.

[0006] Specifically, this type of solution has the following key drawbacks: First, it lacks a synchronous transmission mechanism adapted to the rotational characteristics of VAWT, which can easily cause changes in the mass distribution of the blades during the extension and retraction process, leading to the risk of dynamic imbalance. Furthermore, under the combined action of centrifugal load and aerodynamic force, the positional stability and structural reliability of the extension section are difficult to guarantee. Second, it lacks an effective locking and repositioning structure, which cannot cope with the impact of centrifugal load under rotational conditions, and the position of the extension section is prone to drift or backlash. Third, the transition between the extension section and the main blade lacks a continuous design, which can easily form steps or gaps, thereby inducing airflow separation, generating noise and additional pulsating loads, which in turn weakens the aerodynamic performance benefits.

[0007] In summary, existing technologies, whether fixed airfoil / fixed cross-section blades or traditional retractable blades, suffer from poor adaptability to wide operating conditions, insufficient dynamic stall suppression capabilities, suboptimal stability and reliability under rotating conditions, and difficulty in effectively guaranteeing aerodynamic benefits. These limitations fail to meet the practical requirements of H-type VAWTs for efficient, stable, and all-condition operation under complex wind conditions. Therefore, there is an urgent need to develop a dual-end synchronous retractable variable cross-section blade device for vertical axis wind turbines and its control method to address these issues. Summary of the Invention

[0008] This application provides a device for a vertical axis wind turbine with a dual-end synchronous telescopic variable cross-section blade and its control method, which has the advantages of improving the aerodynamic efficiency and operational stability of the blade under a wide range of operating conditions, reducing the risk of vibration and structural fatigue, and ensuring the continuity of the aerodynamic shape.

[0009] This application provides a dual-end synchronous telescopic variable cross-section blade device for vertical axis wind turbines, the technical solution of which is as follows: The thick airfoil bearing body, as the main stress-bearing and load-bearing component of the blade, adopts a thick airfoil profile to improve the airflow adhesion and anti-stall performance under medium and low tip speed ratio conditions. Thin airfoil retractable blade segments are embedded inside the spanwise ends of the thick airfoil support body, and adopt a thin airfoil profile to extend under high tip speed ratio conditions to optimize the aerodynamic shape of the blades. The thick airfoil-shaped load-bearing body is fixedly installed on the vertical axis wind turbine shaft via a cross arm; An actuator, mounted on the thick airfoil-shaped support body, is used to provide the driving force for the extension and retraction of the thin airfoil-shaped retractable blade segment; The transmission mechanism is installed on the thick airfoil-shaped bearing body and connected to the actuator. It is used to transmit driving force to the thin airfoil-shaped retractable blade segment. The transmission mechanism is a synchronous transmission structure, so that the thin airfoil-shaped retractable blade segments at both ends can extend or retract synchronously. A locking and positioning structure is set between the thick airfoil-shaped load-bearing body and the thin airfoil-shaped retractable blade segment to achieve reliable locking and positioning when the thin airfoil-shaped retractable blade segment is fully retracted or extended into place. The guide and overlap structure is set at the junction of the thick airfoil-shaped load-bearing body and the thin airfoil-shaped retractable blade segment to achieve a continuous transition of the outer surfaces of the two after expansion and contraction. The wind speed detection module and the rotational speed detection module are installed on the vertical axis wind turbine shaft; The control unit is electrically connected to the wind speed detection module, the rotation speed detection module, and the actuator. It is used to receive detection signals and output control commands to drive the actuator to extend and retract the thin airfoil retractable blade segment through the transmission mechanism, and cooperate with the locking and positioning structure to achieve stable switching.

[0010] Furthermore, the airfoil of the thick airfoil bearing body is NACA0021 or an equivalent thick airfoil; the airfoil of the thin airfoil retractable blade segment is NACA0012 or an equivalent thin airfoil.

[0011] Furthermore, the synchronous transmission structure can be any one of the following: gear linkage mechanism, synchronous lead screw mechanism, synchronous belt / chain drive-dual slider mechanism, hydraulic / pneumatic linear actuation mechanism, and actuation mechanism based on shape memory alloy / magnetostriction.

[0012] Furthermore, the actuator is any one of a motor, hydraulic cylinder, pneumatic cylinder, shape memory alloy actuator, or magnetostrictive actuator.

[0013] Furthermore, the locking and positioning structure includes a locking pin and a locking groove. When the thin-wing retractable blade segment extends into position, the locking pin rotates out into the locking groove on the thin-wing retractable blade segment; when the thin-wing retractable blade segment retracts into position, the locking pin rotates back into the thick-wing bearing body.

[0014] Furthermore, the guiding and overlapping structure is a composite material elastic skin.

[0015] Furthermore, the maximum extension of the thin-bladed retractable blade segment is 20% to 35% of the blade spanwise height.

[0016] Furthermore, the wind speed detection module is any one of a three-cup anemometer, an ultrasonic anemometer, a hot-film anemometer, or a Pitot tube anemometer; the rotational speed detection module is any one of an encoder or a Hall sensor.

[0017] A control method for a vertical axis wind turbine with a dual-end synchronous telescopic variable cross-section blade device includes the following steps: S1: Real-time acquisition of incoming wind speed signal through wind speed detection module, and real-time acquisition of rotor angular velocity signal through rotation speed detection module; S2: The control unit calculates the tip speed ratio (TSR) based on the incoming airflow velocity signal and the rotor angular velocity signal. The calculation formula is as follows: , where ω is the rotor angular velocity, R is the rotor radius, and V is the incoming airflow speed; S3: The control unit determines the target extension position of the thin airfoil retractable blade segment based on the preset tip speed ratio (TSR) - extension ratio / extension length correspondence. S4: The control unit outputs control commands to drive the actuator to extend or retract the thin airfoil-shaped retractable blade segment along the spanwise direction through the transmission mechanism; S5: When the thin airfoil retractable blade segment reaches the target position, the locking and positioning structure is triggered to complete the locking in place; S6: Set hysteresis interval, minimum hold time or amplitude limiting protection strategy during the control process to avoid frequent switching near the critical tip speed ratio.

[0018] Furthermore, the relationship between tip speed ratio (TSR) and extension ratio / extension length in step S3 is as follows: when the TSR is less than 20% of the optimal TSR, the thin airfoil retractable blade segment is fully retracted and fits into the thick airfoil supporting body; when the TSR is in the range from the lowest TSR to the highest TSR, the actuator extends the thin airfoil blade step by step according to the calculated value and provides real-time feedback on the position to achieve closed-loop correction; when the TSR is more than 20% of the optimal TSR, the thin airfoil retractable blade segment extends to the maximum extension amount.

[0019] The beneficial effects of this application are:

[0020] 1. The thin-bladed retractable blade segments of this application are preferably located at both ends of the thick-bladed main blade (i.e., near the upper and lower ends of the blade), and symmetrical or synchronous extension and retraction at both ends are achieved through a synchronous transmission mechanism. Symmetrical / synchronous extension and retraction reduces the risk of center of mass shift and dynamic imbalance caused by changes in mass distribution during blade extension and retraction, thereby improving the operational stability and reliability of the H-type VAWT under rotating conditions. The synchronous transmission mechanism can be implemented using gear linkages, double rack and pinion gears, synchronous lead screws, or other equivalent synchronization methods to ensure that the extension amounts of the thin-bladed segments at both ends are consistent or proportionally consistent, thus guaranteeing the repeatability of the variable cross-section shape.

[0021] 2. This application provides an elastic skin at the junction of the thick airfoil-type load-bearing body and the thin airfoil-type retractable blade segment to achieve a continuous transition of the outer surface after the extension and retraction of the two, to limit the motion trajectory of the thin airfoil segment and to achieve a continuous transition of the shape after extension / retraction, thereby reducing the additional separation and noise risks caused by steps / gaps, and thus improving the feasibility and stability of the aerodynamic benefits brought by extension and retraction.

[0022] 3. This application proposes a composite variable cross-section blade structure for a straight-blade H-type vertical axis wind turbine. The blade includes a thick airfoil support body and a thin airfoil retractable blade segment disposed inside the thick airfoil support body. The thin airfoil retractable blade segment extends or retracts along the blade spanwise (height direction) to achieve adjustable equivalent airfoil thickness distribution and effective aerodynamic height. Under low wind speed or low TSR conditions (TSR below 20% of the optimal TSR), the control system causes the thin airfoil retractable blade segment to fully retract along the spanwise direction. The thin airfoil retractable blade segment fits snugly against the thick airfoil support body, and the blade as a whole presents a thick airfoil structure to improve airflow adhesion, self-starting performance, and effectively suppress dynamic stall. Under medium-high wind speed or high TSR conditions (TSR above 20% of the optimal TSR), the thin airfoil blade gradually extends, with a maximum extension of 20% to 35% of the blade spanwise height. Thus, under different tip speed ratio conditions, it takes into account both the adhesion / anti-stall capability under low TSR and the high lift-to-drag ratio efficiency under high TSR.

[0023] 4. To prevent the telescopic section from drifting or shifting back under centrifugal load and aerodynamic force, this invention incorporates a locking and positioning structure. When the thin airfoil telescopic blade segment extends, the actuator synchronously controls the locking pin to rotate out to the locking groove on the thin airfoil telescopic blade segment. When the thin airfoil telescopic blade segment retracts, the actuator synchronously controls the locking pin to rotate back into the thick airfoil segment, ensuring that the thin airfoil segment is reliably locked at the critical position of "fully retracted / extended in place," and maintaining positioning accuracy during multiple switching operations, thereby ensuring aerodynamic consistency and long-term operational reliability.

[0024] 5. The control unit of this application is electrically connected to the wind speed detection module, the rotational speed detection module, and the actuator, respectively. Preferably, the rotational speed signal is further collected, and the extension control command is output based on the tip speed ratio (TSR) or its equivalent operating state quantity to realize closed-loop adaptive adjustment of "operating state - extension ratio / extension length - aerodynamic shape". The hysteresis range, minimum holding time, or limiting strategy can be set to avoid frequent switching near the critical wind speed / TSR, thereby improving control stability and actuator life. Attached Figure Description

[0025] For ease of explanation, this application is described in detail below with reference to specific embodiments and accompanying drawings.

[0026] Figure 1This is a structural schematic diagram of the present application (thin-wing retractable blade segment in retracted state). Figure 2 This is a structural schematic diagram of this application (thin-wing retractable blade segment in extended state). Figure 3 This is a structural schematic diagram of the thick airfoil load-bearing body and the thin airfoil retractable blade segment in this application; Figure 4 This is a schematic diagram of the locking pin rotating when the thin-bladed retractable blade segment of this application is retracted by half; Figure 5 This is a schematic diagram showing the locking pin unscrewing when the thin-bladed retractable blade segment of this application is half-extended; Figure 6 This is a schematic diagram of the locking groove on the thin-bladed retractable blade segment of this application; Figure 7 This is a schematic diagram of the control unit structure of this application; Figure 8 This is a schematic diagram of the wind speed detection module in this application being a three-cup anemometer; Figure 9 This is a schematic diagram of the elastic skin state when the thin-winged retractable blade segment in this application contracts; Figure 10 This is a schematic diagram of the flexible over-elastic skin state when the thin-wing retractable blade segment extends in this application; Figure 11 This is a schematic diagram of the flexible over-elastic skin state when the thin-wing retractable blade segment extends in this application; Figure 12 This application describes the power coefficient of the H-type VAWT with different blades as a function of tip speed ratio. Figure 13 This is a schematic diagram of the synchronous transmission structure of the technical solution of this application when it is a gear and connecting rod mechanism.

[0027] In the diagram: 1. Thick airfoil-shaped load-bearing body; 2. Thin airfoil-shaped retractable blade segment; 3. Vertical axis wind turbine shaft; 4. Cross arm; 5. Actuator; 6. Transmission mechanism; 7. Locking pin; 8. Locking groove; 9. Guide and overlapping structure; 10. Control unit; 11. Wind speed detection module; 12. Upper connecting rod; 13. Drive gear; 14. Lower connecting rod. Detailed Implementation

[0028] The following are specific embodiments of this application, described in conjunction with the accompanying drawings, to further illustrate the technical solutions of this application. However, this application is not limited to these embodiments. Specific details, such as particular configurations and components, are provided in the following description merely to aid in a comprehensive understanding of the embodiments of this application. Therefore, those skilled in the art should understand that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of this application. Furthermore, for clarity and brevity, descriptions of known functions and structures have been omitted.

[0029] It should be noted that, where there is no conflict, the embodiments and features described in this application can be combined with each other.

[0030] like Figure 1-11 The specific embodiment of the vertical axis wind turbine double-end synchronous telescopic variable cross-section blade device shown includes: Thick airfoil bearing body 1, the airfoil of the thick airfoil bearing body 1 is NACA0021 or equivalent thick airfoil, as the main force and load-bearing component of the blade, adopts thick airfoil profile to improve airflow adhesion and anti-stall performance under medium and low blade tip speed ratio conditions. Thin airfoil retractable blade segment 2, the airfoil of thin airfoil retractable blade segment 2 is NACA0012 or equivalent thin airfoil, embedded in the spanwise ends of the thick airfoil bearing body 1, adopting a thin airfoil profile, used to extend under high tip speed ratio conditions to optimize the aerodynamic shape of the blade. The vertical axis wind turbine shaft 3, the thick airfoil bearing body 1 is arranged around the circumference of the vertical axis wind turbine shaft 3, and the thick airfoil bearing body 1 is fixedly installed to the vertical axis wind turbine shaft 3 through the cross arm 4; Actuator 5 is used to provide the driving force for the extension and retraction of the thin-bladed retractable blade segment; The transmission mechanism 6 is connected to the actuator 5 and is used to transmit the driving force to the thin airfoil retractable blade segment 2. The transmission mechanism 6 is a synchronous transmission structure, so that the thin airfoil retractable blade segments 1 at both ends can extend or retract synchronously. A locking and positioning structure is provided between the thick-wing-shaped load-bearing body 1 and the thin-wing-shaped retractable blade segment 2. It includes a locking pin 7 and a locking groove 8. When the thin-wing-shaped retractable blade segment 2 is extended into the position, the locking pin 7 is screwed out into the locking groove 8 on the thin-wing-shaped retractable blade segment 2. When the thin-wing-shaped retractable blade segment 2 is retracted into the position, the locking pin 7 is screwed back into the thick-wing-shaped load-bearing body 1. This structure is used to reliably lock and position the thin-wing-shaped retractable blade segment 2 when it is fully retracted or extended into the position, preventing the thin-wing-shaped retractable blade segment 2 from shifting during operation.

[0031] The guide and overlap structure 9, which is a composite material elastic skin, is located at the junction of the thick airfoil-shaped load-bearing body 1 and the thin airfoil-shaped retractable blade segment 2 to achieve a continuous transition of the outer surfaces of the two after expansion and contraction (e.g., Figures 9 to 11 (as shown) The wind speed detection module 11 and the rotation speed detection module are installed on the vertical axis wind turbine shaft 3; The control unit 10 is electrically connected to the wind speed detection module, the rotation speed detection module, and the actuator, respectively. It is used to receive detection signals and output control commands to drive the actuator 5 to extend and retract the thin airfoil retractable blade segment 2 through the transmission mechanism 6, and cooperate with the locking and positioning structure to achieve stable switching.

[0032] Specifically, the maximum extension of the thin-wing retractable blade segment 2 is 20% to 35% of the blade spanwise height.

[0033] Specifically, the above-mentioned vertical axis wind turbine double-end synchronous telescopic variable cross-section blade device has two typical operating states: (1) When the thin-bladed retractable blade segment 2 is in the retracted state (thick airfoil mode): When the wind turbine is in a low to medium TSR condition (e.g., below a certain threshold range of the optimal TSR), the control unit 10 drives the actuator 5 to retract the thin-bladed retractable blade segment 2 along the spanwise direction and embed it into the thick airfoil supporting body 1 (e.g. Figure 1 , Figure 4 (As shown). At this point, the blade shape is equivalent to a thick airfoil profile, which can enhance airflow adhesion, improve start-up / stall resistance, and suppress dynamic stall.

[0034] (2) When the thin airfoil retractable blade segment 2 is in the extended state (composite variable cross section mode): When the wind turbine is in a medium-high TSR condition (e.g., above a certain threshold range of the optimal TSR), the control unit 10 drives the actuator 5 to extend the thin airfoil retractable blade segment 2 out of the thick airfoil supporting body 1 (e.g., Figure 2 and Figure 5 This results in a composite variable cross-section structure: the middle section of the blade maintains a thick airfoil profile, while the extended portions at both ends have a thin airfoil profile, with the maximum extension being 20% ​​to 35% of the blade spanwise height. Through this composite shape, the equivalent thickness distribution and effective aerodynamic shape can be adjusted without changing the rotor radius, thereby improving the lift-to-drag ratio and power output capability under high TSR conditions, and improving end flow characteristics.

[0035] Specifically, the wind speed detection module 11 is any one of a three-cup anemometer, an ultrasonic anemometer, a hot-film anemometer, or a Pitot tube anemometer; the rotational speed detection module is an encoder or a Hall sensor. In this application, the wind speed detection module 11 is preferably a three-cup anemometer (such as...). Figure 8 As shown in the figure, the speed detection module is preferably an encoder.

[0036] Specifically, such as Figure 9-11 As shown, a composite elastic skin is set between the thick airfoil-shaped load-bearing body 1 and the thin airfoil-shaped retractable blade segment 2, so that the thin airfoil-shaped retractable blade segment 2 can extend or retract and transition continuously with the outer surface of the thick airfoil-shaped load-bearing body 1. This reduces the adverse effects of geometric abrupt changes such as steps and gaps on the boundary layer, and reduces the additional separation, noise and pulsating loads caused by them, thereby ensuring that the "benefits brought by variable geometry" are not offset by the shape discontinuity effect.

[0037] Specifically, such as Figure 12 As shown, the power coefficient variations of the constant cross-section blades (NACA0012, NACA0015, NACA0021) and the variable cross-section blades of this application under different TSRs are compared using computational fluid dynamics methods. Figure 12 It is evident that within the low to medium TSR range, the power coefficient of thick-airfoil blades is higher than that of thin-airfoil blades; conversely, within the higher TSR range, the power coefficient of thin-airfoil blades is higher than that of thick-airfoil blades. Variable-section blades maintain a relatively high power coefficient across a wide TSR range, demonstrating their adaptability to different operating conditions. This, in turn, helps to broaden the usable operating range of H-type VAWTs of the same scale and improve overall operational stability.

[0038] Specifically, the actuator 5 can be any one of a motor, hydraulic cylinder, pneumatic cylinder, shape memory alloy actuator, or magnetostrictive actuator. The synchronous transmission structure 6 can be any one of a gear linkage mechanism, synchronous lead screw mechanism, synchronous belt / chain drive-dual slider mechanism, hydraulic / pneumatic linear actuator, and actuator based on shape memory alloy / magnetostriction.

[0039] Specifically, the actuator 5 corresponds to the synchronous transmission structure 6. When the synchronous transmission structure 6 is a gear linkage mechanism, a synchronous lead screw mechanism, or a synchronous belt / chain drive-double slider mechanism, the actuator 5 is a motor; when the synchronous transmission structure 6 is a hydraulic linear actuation mechanism, the actuator 5 is a hydraulic cylinder; when the synchronous transmission structure 6 is a pneumatic linear actuation mechanism, the actuator 5 is a pneumatic cylinder; when the synchronous transmission structure 6 is an actuation mechanism based on shape memory alloys, the actuator 5 is a shape memory alloy actuator; when the synchronous transmission structure 6 is a magnetostrictive actuation mechanism, the actuator 5 is a magnetostrictive actuator.

[0040] Specifically, in this application, the actuator 5 is preferably a motor, and the synchronous transmission structure 6 is preferably a gear and linkage mechanism (such as...). Figure 13 (As shown). The gear linkage mechanism includes: a motor, a drive gear 13 connected to the motor output shaft, and an upper connecting rod 12 and a lower connecting rod 14 disposed on both sides of the drive gear and meshing with the drive gear. The two connecting rods are connected to the corresponding thin airfoil retractable blade segment 2.

[0041] When the synchronous transmission structure 6 is preferably a gear linkage mechanism, the working process of this application is as follows: the wind speed detection module 11 collects the wind speed signal, and the control unit 10 (which can calculate TSR in combination with the rotation speed signal) outputs control commands for the motor to rotate forward or backward; when the drive gear 13 rotates in the first direction, the upper linkage 12 and the lower linkage 14 move in opposite directions with equal strokes, thereby driving the thin airfoil retractable blade segment 2 to extend synchronously; when the drive gear 13 rotates in the reverse direction, the upper and lower linkages move in opposite directions with equal strokes, thereby driving the thin airfoil retractable blade segment 2 to retract synchronously.

[0042] The advantages of this scheme are: forced synchronization of the upper and lower (or both ends) extension sections is achieved through a single drive gear 13, resulting in good stroke consistency, which helps to reduce the risk of centroid shift and dynamic imbalance caused by extension; at the same time, the structure is compact and easy to arrange in the internal space of the blade.

[0043] In other preferred embodiments, based on the above technical solution, the actuator 5 is a motor, and the synchronous transmission structure 6 is a synchronous lead screw mechanism.

[0044] Specifically, a motor and a lead screw-nut pair are used to convert the motor's rotary motion into linear motion, driving the thin-bladed retractable blade segment to extend / retract. To achieve synchronization at both ends, the following can be used: dual lead screw coaxial synchronization (gear synchronization / synchronous belt synchronization); or a symmetrical structure with one lead screw driving two sliders. The advantages of this scheme are large linear thrust, good position controllability, and easy integration with limit switches and position feedback.

[0045] In other preferred embodiments, based on the above technical solution, the actuator 5 is a motor, and the synchronous transmission structure 6 is a synchronous belt / chain drive-double slider mechanism.

[0046] Specifically, a motor drives two sliders to move symmetrically along a guide rail via a synchronous belt (or chain), connecting the upper and lower (two ends) thin-bladed retractable blade segments to achieve symmetrical extension and retraction. Advantages include low noise, a relatively flexible structure, and ease of long-distance power source placement and synchronization via belt / chain.

[0047] In other preferred embodiments, based on the above technical solution, the actuator 5 is a hydraulic cylinder / pneumatic cylinder, and the synchronous transmission structure 6 is a hydraulic / pneumatic linear actuator.

[0048] Specifically, extension / retraction is achieved through a valve-controlled system; synchronization at both ends can be achieved through parallel circuits, synchronizing valves, or mechanical linkages. The advantages are high output force and fast response, making it suitable for applications with large blades or requiring significant thrust.

[0049] In other preferred embodiments, based on the above technical solutions, the actuator 5 is a shape memory alloy actuator / the actuator is a magnetostrictive actuator, and the synchronous transmission structure 6 is an actuator based on shape memory alloy / magnetostriction.

[0050] Specifically, in small and medium-sized units or specific lightweight applications, shape memory alloys or magnetostrictive actuators can be used as actuating elements, combined with guiding and locking structures to achieve telescopic movements. This solution is suitable for applications with small strokes and high requirements for structural integration.

[0051] A control method for a vertical axis wind turbine with a dual-end synchronous telescopic variable cross-section blade device includes the following steps: S1: The wind speed detection module 11 collects the incoming wind speed signal in real time, and the rotor angular velocity signal is collected in real time through the rotation speed detection module. S2: Control unit 10 calculates the tip speed ratio (TSR) based on the incoming air velocity signal and the rotor angular velocity signal. The calculation formula is as follows: , where ω is the rotor angular velocity collected in real time by the rotation speed detection module, R is the rotor radius (known data), and V is the incoming wind speed collected in real time by the wind speed detection module 11; S3: The control unit 10 determines the target extension position of the thin airfoil retractable blade segment 2 according to the preset tip speed ratio TSR-extension ratio / extension length correspondence; S4: Control unit 10 outputs control commands to drive actuator 5 to extend or retract the thin airfoil retractable blade segment 2 along the spanwise direction via transmission mechanism 6; S5: When the thin-bladed retractable blade segment 2 reaches the target position, the locking and positioning structure is triggered to complete the locking in place; S6: Set hysteresis interval, minimum hold time or amplitude limiting protection strategy during the control process to avoid frequent switching near the critical tip speed ratio.

[0052] Specifically, in step S6, to avoid frequent switching near critical operating conditions, the present invention preferably sets a hysteresis range, minimum holding time, or amplitude limiting protection strategy: for example, setting an upper and lower threshold range centered on the optimal TSR (which can be "entering the retraction mode at a certain percentage below the optimal TSR and entering the extension mode at a certain percentage above the optimal TSR"), and adding a minimum holding time or amplitude limiting strategy to improve control stability and reduce the wear risk caused by frequent actuator movements.

[0053] Specifically, the relationship between tip speed ratio (TSR) and extension ratio / extension length in step S3 is as follows: when the TSR is less than 20% of the optimal TSR, the thin airfoil retractable blade segment 2 is fully retracted and fits into the thick airfoil supporting body 1; when the TSR is in the range from the lowest TSR to the highest TSR, the actuator 5 extends the thin airfoil retractable blade segment 2 step by step according to the calculated value, and provides real-time feedback on the position to achieve closed-loop correction; when the TSR is more than 20% of the optimal TSR, the thin airfoil retractable blade segment 2 extends to the maximum extension amount.

[0054] Specifically, "optimal TSR" refers to the tip speed ratio at which a vertical axis wind turbine achieves its maximum power coefficient under specific design conditions. When the actual tip speed ratio is much lower than this optimal value, it usually corresponds to low wind speeds or the wind turbine startup phase. Under this condition, the thin-bladed retractable blade segment 2 is completely retracted, so that the blade as a whole presents the thick airfoil profile provided by the thick airfoil supporting body 1. This thick airfoil profile has superior airflow adhesion and anti-stall performance under medium and low tip speed ratio conditions, which helps the wind turbine to start up smoothly and maintain stable operation at low wind speeds.

[0055] Specifically, when the tip speed ratio (TSR) is between the lowest and highest TSR, the actuator extends the thin-bladed retractable blade segment 2 step by step according to the calculated value, and provides real-time position feedback to achieve closed-loop correction. This range represents the main operating range of the vertical axis wind turbine. Within this range, to maximize wind energy capture efficiency, the extension amount of the thin-bladed retractable blade segment 2 needs to be precisely adjusted according to the real-time tip speed ratio (TSR). The term "step-by-step extension" means that the extension amount of the thin-bladed retractable blade segment is not all at once, but rather, based on the change in the tip speed ratio (TSR), the actuator 5 gradually drives the thin-bladed retractable blade segment 2 to extend or retract to the target position along the spanwise direction, according to the command output by the control unit 10.

[0056] Specifically, the minimum TSR refers to the minimum tip speed ratio threshold at which the wind turbine can maintain continuous and stable rotation and generate effective output power under the given conditions of structural parameters, generator load, and control strategy. It typically corresponds to the wind turbine's startup or low-wind-speed operation. When the tip speed ratio is below this minimum TSR, the wind turbine's startup efficiency decreases significantly, and the blades are prone to deep stall or unstable operation. The maximum TSR refers to the maximum tip speed ratio threshold at which the wind turbine can maintain stable operation for long or short periods, limited by structural strength, aerodynamic load, and safety requirements. It typically corresponds to high-wind-speed or light-load operation. When the tip speed ratio exceeds this maximum TSR, the blade aerodynamic load, centrifugal load, and structural stress increase significantly, potentially adversely affecting system safety and reliability. The minimum and maximum TSRs are not fixed constants but can be set or adaptively adjusted according to the wind turbine's specific dimensions, airfoil configuration, generator characteristics, and control objectives. Together, they define the main controllable operating range of the vertical axis wind turbine.

[0057] Specifically, when the tip speed ratio (TSR) is 20% higher than the optimal TSR, the thin-airfoil retractable blade segment 2 extends to its maximum extension. This operating condition typically corresponds to higher wind speeds. At high tip speed ratios, to reduce blade drag, improve aerodynamic efficiency, and prevent wind turbine overspeed, the thin-airfoil retractable blade segment 2 is fully extended to its maximum physical extension, resulting in a thinner blade with a higher aspect ratio. This thin airfoil profile effectively optimizes the aerodynamic shape of the blade under high tip speed ratio conditions, reducing aerodynamic drag and thus effectively controlling blade load and improving operational safety while ensuring wind energy capture.

[0058] Specifically, through the above technical solution, this application provides a refined and adaptive variable cross-section control strategy for vertical axis wind turbine blades. Under low tip speed ratio (TSR) conditions, by fully retracting the thin-bladed retractable blade segment 2, the blade adopts a thick airfoil shape, effectively improving the wind turbine's start-up performance and aerodynamic efficiency at low wind speeds, and avoiding stall. In the main operating range, through a step-by-step, closed-loop precise correspondence between the tip speed ratio (TSR) and the retraction ratio / extension length, the blade can dynamically adjust its aerodynamic shape according to real-time wind conditions and rotational speed, always maintaining it at or near the optimal aerodynamic efficiency point, thereby maximizing wind energy capture. Under high tip speed ratio conditions, the thin-bladed retractable blade segment 2 extends to its maximum extension, making the blade a thin airfoil shape, effectively reducing aerodynamic drag, controlling blade load, and ensuring the wind turbine's operational safety and stability at high wind speeds. Overall, this control method significantly improves the aerodynamic performance, energy capture efficiency, and operational reliability of vertical axis wind turbines across the entire operating range, while reducing unnecessary frequent switching and extending equipment lifespan.

[0059] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0060] In the description of this application, it should be understood that the terms "upper" and "lower" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0061] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0062] Those skilled in the art to which this application pertains may make various modifications or additions to the specific embodiments described, or adopt similar methods to replace them, without departing from the spirit of this application or exceeding the scope defined by the appended claims.

Claims

1. A double ended telescopic variable camber blade device for vertical axis wind turbines, characterised in that, The application relates to a vertical axis wind turbine blade with thick and thin airfoil profiles. The application comprises the following parts: a thick airfoil profile bearing main body serving as a main force bearing component of the blade, which adopts a thick airfoil profile to improve the air flow adhesion capacity and stall resistance performance under a medium and low tip speed ratio condition; thin airfoil profile retractable blade segments embedded in the inside of the two ends of the thick airfoil profile bearing main body in the spanwise direction, which adopt a thin airfoil profile and are used to be extended under a high tip speed ratio condition to optimize the blade aerodynamic shape; a vertical axis wind turbine rotating shaft, wherein the thick airfoil profile bearing main body is fixedly installed on the vertical axis wind turbine rotating shaft through a cross arm; an actuator installed on the thick airfoil profile bearing main body and used to provide a driving force for the extension and retraction of the thin airfoil profile retractable blade segments; a transmission mechanism installed on the thick airfoil profile bearing main body and connected with the actuator, which is used to transmit the driving force to the thin airfoil profile retractable blade segments, and the transmission mechanism is a synchronous transmission structure, so that the thin airfoil profile retractable blade segments at the two ends are synchronously extended or retracted; a locking and positioning structure arranged between the thick airfoil profile bearing main body and the thin airfoil profile retractable blade segments, which is used to reliably lock and position when the thin airfoil profile retractable blade segments are completely retracted or extended to the position; a guide and lapping structure arranged at the joint of the thick airfoil profile bearing main body and the thin airfoil profile retractable blade segments, which is used to realize the continuous transition of the outer surfaces after the extension and retraction of the two parts; a wind speed detection module and a rotating speed detection module arranged on the vertical axis wind turbine rotating shaft; 2. The double end synchronous telescopic variable camber blade arrangement for a vertical axis wind turbine as claimed in claim 1 wherein, a control unit electrically connected with the wind speed detection module, the rotating speed detection module and the actuator, which is used to receive detection signals and output control instructions, drive the actuator to drive the thin airfoil profile retractable blade segments to extend and retract through the transmission mechanism, and realize stable switching through cooperation with the locking and positioning structure.

3. The double end synchronous telescopic variable camber blade arrangement for vertical axis wind turbine as claimed in claim 1 wherein, The airfoil profile of the thick airfoil profile bearing main body is NACA0021 or an equivalent thick airfoil profile; the airfoil profile of the thin airfoil profile retractable blade segments is NACA0012 or an equivalent thin airfoil profile.

4. The double end synchronous telescopic variable camber blade arrangement for a vertical axis wind turbine as claimed in claim 3 wherein, The synchronous transmission structure is any one of a gear connecting rod mechanism, a synchronous screw mechanism, a synchronous belt / chain transmission-double sliding block mechanism, a hydraulic / pneumatic linear actuating mechanism and a shape memory alloy / magnetostrictive actuating mechanism.

5. The double end synchronous telescopic variable camber blade arrangement for a vertical axis wind turbine as claimed in claim 1, wherein, The actuator is any one of a motor, a hydraulic cylinder, a pneumatic cylinder, a shape memory alloy actuator or a magnetostrictive actuator.

6. The Double-End Synchronous Telescopic Variable Camber Blade Arrangement for Vertical Axis Wind Turbines as claimed in claim 1, wherein, The locking and positioning structure comprises a locking pin and a locking groove, wherein when the thin airfoil profile retractable blade segments are extended to the position, the locking pin is rotated into the locking groove on the thin airfoil profile retractable blade segments; and when the thin airfoil profile retractable blade segments are retracted to the position, the locking pin is rotated back to the inside of the thick airfoil profile bearing main body.

7. The Double-End Synchronous Telescopic Variable Camber Blade Arrangement for Vertical Axis Wind Turbines as claimed in claim 1, wherein, The guide and lapping structure is a composite material elastic skin.

8. The double end synchronous telescopic variable camber blade arrangement of the vertical axis wind turbine as claimed in claim 1 wherein, The maximum extension amount of the thin airfoil profile retractable blade segments is 20%-35% of the blade spanwise height.

9. A control method of the double end synchronous telescopic variable camber blade device of the vertical axis wind turbine as claimed in any one of the claims 1 to 8, wherein, The wind speed detection module is any one of a three-cup anemometer, an ultrasonic wind speed sensor, a hot film type wind speed sensor or a pitot tube type wind speed sensor; and the rotating speed detection module is any one of an encoder or a Hall sensor. The application further discloses a vertical axis wind turbine blade with thick and thin airfoil profiles. The application comprises the following steps: S1: collecting a coming flow wind speed signal in real time through a wind speed detection module and collecting a rotor angular velocity signal in real time through a rotating speed detection module; S2: the control unit calculates the tip speed ratio TSR according to the incoming flow wind speed signal and the rotor angular velocity signal, and the calculation formula is where ω is the rotor angular velocity, R is the rotor radius, and V is the incoming flow wind speed. S3: The control unit determines the target telescopic position of the thin airfoil telescopic blade segment according to a preset tip speed ratio TSR-telescopic ratio / extension length correspondence; S4: The control unit outputs a control instruction to drive the actuating mechanism to drive the thin airfoil telescopic blade segment to extend or retract along the span direction through the transmission mechanism; S5: When the thin airfoil telescopic blade segment reaches the target position, the locking positioning structure is triggered to complete the locking at the position; S6: A hysteresis interval, minimum holding time or amplitude limiting protection strategy is set in the control process to avoid frequent switching near the critical tip speed ratio.

10. The control method of the double end synchronous telescopic variable camber blade arrangement of the vertical axis wind turbine as claimed in claim 9, wherein, The tip speed ratio TSR-telescopic ratio / extension length correspondence in step S3 is as follows: when TSR is lower than 20% of the optimal TSR, the thin airfoil telescopic blade segment is completely retracted and adheres to the thick airfoil bearing main body; when TSR is in the interval from the minimum TSR to the maximum TSR, the actuating mechanism gradually extends the thin airfoil blade according to the calculated value, and real-time feedback position is realized to achieve closed-loop correction; when TSR is higher than 20% of the optimal TSR, the thin airfoil telescopic blade segment is extended to the maximum extension amount.

Images