Operation control method and device for vertical axis wind turbine generator

Abstract

The invention discloses an operation control method and device for a vertical axis wind turbine generator, and belongs to the technical field of wind power generation. The method comprises the steps that a pitch angle of a lower blade is driven to be gradually increased to a preset angle at a preset angular speed through a variable pitch controller; when the rotating speed of the wind wheel reaches the cut-in rotating speed, the optimal tip speed ratio is tracked until the rotating speed of the wind wheel rises to the rated rotating speed; when the rotating speed of the wind wheel reaches the rated rotating speed, the rotating speed of the wind wheel is stabilized at the rated rotating speed; when the driving torque under the action of the aerodynamic load continuously exceeds the rated torque of the generator and the rotating speed of the generator reaches an early-warning rotating speed threshold value, a shutdown control strategy is triggered; and under the shutdown control strategy, the connection between the generator and the power grid is cut off, and mechanical braking is applied, so that the wind wheel stops rotating. According to the technical scheme, smooth starting of the wind wheel, stable operation at the rated rotating speed and safe shutdown in the fault state are achieved, the starting and stopping capacity and power stability of the unit are effectively improved, the wind speed application range is expanded, and it is guaranteed that the whole-process operation of the unit is safe and reliable.

Description

Technical Field

[0001] This invention relates to the technical field of wind power generation, and in particular to an operation control method and device for a vertical axis wind turbine. Background Technology

[0002] Wind power, as a clean energy source, boasts advantages such as high efficiency, greenness, and low carbon footprint. Driven by the global energy transition, it has become a crucial pillar of renewable energy development. Existing wind turbine units mainly include horizontal-axis and vertical-axis wind turbine units. Horizontal-axis wind turbine units have traditionally dominated the market due to their high aerodynamic efficiency and large single-unit capacity. However, with the rapid development of offshore wind power technology in recent years, vertical-axis wind turbine units have gradually regained industry attention due to their characteristics, such as no need for active yaw alignment, relatively simple structure, lower maintenance costs, smaller wake effect, and suitability for cluster deployment. Nevertheless, vertical-axis wind turbine units still face challenges in practical applications, including lower efficiency (aerodynamic power coefficient typically less than 0.3), complex operation and control, and insufficient reliability. This has resulted in their share of global installed capacity being less than 2%, limiting their widespread adoption.

[0003] Currently, the mainstream vertical axis wind turbine structures are mostly Φ-type or H-type. These types of units generally lack effective aerodynamic regulation capabilities and rely mainly on generator torque control for operation. This not only places high demands on generator performance but also presents difficulties during unit startup and shutdown, and there is a lack of countermeasures for fault conditions. How to achieve engineering controllability throughout the entire operation process of vertical axis wind turbines has become an urgent issue for the industry. Summary of the Invention

[0004] This invention provides a method and apparatus for operating control of a vertical axis wind turbine, which enables smooth start-up, stable rated speed and safe shutdown in case of failure, effectively improves power stability and wind speed adaptability, reduces ultimate load, and ensures safe operation of the vertical axis wind turbine throughout the entire process.

[0005] According to a first aspect of the present invention, an operation control method for a vertical axis wind turbine is provided, the operation control method for the vertical axis wind turbine includes: During the unit startup phase, after releasing the mechanical brake of the wind turbine and confirming that the wind speed has reached the cut-in wind speed, the pitch angle of the blades is gradually increased to the preset angle by driving the pitch controller at a predetermined angular velocity to form a drag-type wind turbine to increase aerodynamic force. Once the wind turbine speed reaches the cut-in speed, the pitch angle of the lower blade is adjusted to the minimum pitch angle and maintained, and the optimal tip speed ratio is tracked until the wind turbine speed rises to the rated speed. When the wind turbine speed reaches the rated speed, the wind turbine speed is stabilized at the rated speed, and the pitch angle of the lower blade is maintained at the minimum pitch angle until the generator output torque reaches the rated torque. When the driving torque under aerodynamic load continuously exceeds the rated torque of the generator and the generator speed reaches the warning speed threshold, the shutdown control strategy is triggered to increase the pitch angle of the lower blade to suppress the wind turbine speed and establish a closed-loop control between the wind turbine speed and the pitch angle to make the wind turbine enter a deceleration state. Under the shutdown control strategy, the pitch angle of the lower blades is continuously increased until the blades are fully retracted, and the generator torque is gradually reduced. Once the wind turbine speed drops to a safe shutdown speed, the connection between the generator and the power grid is disconnected and a mechanical brake is applied to stop the wind turbine from rotating.

[0006] In one embodiment, the unit start-up phase includes: Release the mechanical brake on the wind turbine, and start the start-up control after confirming that the wind speed has reached the cut-in wind speed and the unit's self-test is normal; The pitch controller drives the lower blades to gradually increase the pitch angle to a preset angle at a predetermined angular velocity, forming a drag-type wind turbine to increase aerodynamic force and drive the wind turbine to rotate faster. When the wind turbine speed rises to the cut-in speed, the startup process ends and the wind turbine enters the normal power generation operation phase.

[0007] In one embodiment, the control during the normal power generation operation phase includes: Under low wind speed conditions, the reference speed of the pitch controller is set as the cut-in speed, and the maximum torque output of the generator is limited by the optimal torque coefficient. At the same time, the pitch angle of the lower blade is kept at the minimum pitch angle to maximize aerodynamic power and promote the continuous acceleration of the wind turbine. Under medium wind speed conditions, the reference speed of the pitch controller is switched to the rated speed, and the pitch angle of the lower blade is maintained at the minimum pitch angle. When the wind turbine speed reaches the rated speed but the generator output power has not yet reached the rated power, the generator output is increased to increase the wind turbine output power. Under high wind speed conditions, the wind turbine speed is stabilized at the rated speed by generator torque control, and the pitch angle of the lower blade is gradually increased by the pitch controller to limit the wind turbine output power within the rated power range for smooth operation.

[0008] In one embodiment, it also includes: When the wind turbine speed or generator speed is detected to reach the warning speed threshold, or when a power grid fault causes the generator to lose load, overspeed suppression control is immediately executed. By increasing the pitch angle of the lower blades, additional aerodynamic drag is applied to the wind turbine to suppress the speed from continuing to rise. The warning speed threshold is higher than the rated speed. The closed-loop shutdown control strategy is initiated to establish a negative feedback control relationship between the wind turbine speed and the pitch angle. The pitch angle of the lower blade is continuously increased to the fully retracted position at a predetermined pitch angle velocity, while the generator torque is gradually reduced to gradually decrease the wind turbine speed. When the wind turbine speed drops to the safe shutdown speed, disconnect the generator from the power grid and apply a mechanical brake to stop the wind turbine.

[0009] In one embodiment, it also includes: The vertical axis wind turbine adopts a segmented blade structure design, consisting of upper blades, middle blades and lower blades connected in sequence by rigid connectors. The lower blade is equipped with a pitch drive mechanism, which drives the lower blade to rotate around its longitudinal axis through a worm gear transmission to change the pitch angle. The aerodynamic power of the wind turbine is controlled by adjusting the pitch angle of the lower blades.

[0010] In one embodiment, it also includes: By monitoring the wind turbine speed in real time, the current operating conditions of the unit can be identified. When the unit is starting up, the wind turbine's starting acceleration capability at low wind speeds can be improved by using partial pitch adjustment in conjunction with generator torque regulation. Under normal power generation conditions, the pitch angle of the lower blades and the torque output of the generator are adjusted in coordination according to the wind speed range to improve the aerodynamic power output at medium wind speeds, reduce the wind turbine load at high wind speeds, and maintain stable output power. In the event of a fault shutdown, the turbine speed is rapidly reduced by combining the Pitch-Kick technology and the closed-loop shutdown control strategy to ensure safe shutdown of the unit. The Pitch-Kick technology refers to a control strategy that achieves rapid speed reduction by superimposing an additional pitch angle on the pitch control output.

[0011] According to a second aspect of the present invention, an operation control device for a vertical axis wind turbine is provided, comprising: The start-up module is used to release the mechanical brake of the wind turbine and confirm that the wind speed has reached the cut-in wind speed during the start-up phase of the unit. Then, through the pitch controller, it drives the blade pitch angle to gradually increase to the preset angle at a predetermined angular velocity to form a drag-type wind turbine to increase aerodynamic force. The adjustment module is used to adjust the pitch angle of the lower blade to the minimum pitch angle and maintain it after the wind turbine speed reaches the cut-in speed, and to track the optimal tip speed ratio until the wind turbine speed rises to the rated speed. The stabilization module is used to stabilize the wind turbine speed at the rated speed when the wind turbine speed reaches the rated speed, and to maintain the pitch angle of the lower blade at the minimum pitch angle until the generator output torque reaches the rated torque. The deceleration module is used to trigger a shutdown control strategy when the driving torque under aerodynamic load continuously exceeds the rated torque of the generator and the generator speed reaches the warning speed threshold. This strategy increases the pitch angle of the lower blade to suppress the wind turbine speed and establishes a closed-loop control between the wind turbine speed and the pitch angle to make the wind turbine enter a deceleration state. The stop module is used to continuously increase the pitch angle of the lower blades until the blades are fully retracted under the shutdown control strategy, and gradually reduce the generator torque. After the wind turbine speed drops to the safe shutdown speed, the generator is disconnected from the grid and a mechanical brake is applied to stop the wind turbine from rotating.

[0012] In one embodiment, when the starting module, the adjustment module, the stabilization module, the deceleration module, and the stop module are controlled to execute, they implement any of the above-described operation control methods for vertical axis wind turbines.

[0013] According to a third aspect of the present invention, an electronic device is provided, comprising: a communication interface, a processor, and a memory; The memory is used to store program instructions, which, when executed by the processor that is connected to the memory via the communication interface, implement any of the above-described operation control methods for vertical axis wind turbines.

[0014] According to a fourth aspect of the present invention, a computer-readable storage medium is provided, on which computer program instructions are stored, which, when executed by a computer (e.g., a processor in a computer), implement any of the above-described operation control methods for vertical axis wind turbine generators.

[0015] In summary, this invention provides an operation control method and apparatus for a vertical axis wind turbine. The method includes: during the turbine startup phase, after releasing the mechanical brake on the wind turbine and confirming that the wind speed has reached the cut-in wind speed, driving the pitch angle of the lower blades to gradually increase to a preset angle via a pitch controller at a predetermined angular velocity, forming a drag-type wind turbine to increase aerodynamic force; when the wind turbine speed reaches the cut-in speed, adjusting the pitch angle of the lower blades to the minimum pitch angle and maintaining it, tracking the optimal tip speed ratio until the wind turbine speed rises to the rated speed; when the wind turbine speed reaches the rated speed, stabilizing the wind turbine speed at the rated speed and maintaining the pitch angle of the lower blades... The pitch angle is maintained at the minimum pitch angle until the generator output torque reaches the rated torque. When the driving torque under aerodynamic load continuously exceeds the generator's rated torque and the generator speed reaches the warning speed threshold, a shutdown control strategy is triggered. This increases the pitch angle of the lower blades to suppress the turbine speed and establishes a closed-loop control between the turbine speed and the pitch angle to induce deceleration. Under the shutdown control strategy, the pitch angle of the lower blades is continuously increased until the blades are fully retracted, and the generator torque is gradually reduced. Once the turbine speed drops to a safe shutdown speed, the connection between the generator and the grid is disconnected, and a mechanical brake is applied to stop the turbine. The technical solution of this application achieves smooth turbine startup, stable operation at rated speed, and safe shutdown under fault conditions through local pitch control and speed-torque coordinated control. This effectively improves the unit's start-up and shutdown capabilities and power stability, expands the wind speed adaptation range, reduces ultimate loads, and ensures safe and reliable operation of the entire unit.

[0016] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and drawings.

[0017] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 A flowchart of an operation control method for a vertical axis wind turbine provided as an embodiment of the present invention; Figure 2 A flowchart of another operation control method for a vertical axis wind turbine provided as an embodiment of the present invention; Figure 3 A flowchart of another operation control method for a vertical axis wind turbine provided as an embodiment of the present invention; Figure 4 A flowchart of another operation control method for a vertical axis wind turbine provided as an embodiment of the present invention; Figure 5 A flowchart of another operation control method for a vertical axis wind turbine provided as an embodiment of the present invention; Figure 6 A flowchart of another operation control method for a vertical axis wind turbine provided as an embodiment of the present invention; Figure 7 A structural diagram of an operation control device for a vertical axis wind turbine provided as an embodiment of the present invention; Figure 8 A structural diagram of an electronic device provided as an embodiment of the present invention; Figure 9 A schematic diagram of a vertical axis wind turbine structure provided for an embodiment of the present invention; Figure 10 A schematic diagram of another pitch actuator structure provided for an embodiment of the present invention; Figure 11 A schematic diagram of a vertical axis wind turbine operation control method provided for an embodiment of the present invention; Figure 12 A schematic diagram of wind turbine speed and power control curves provided for embodiments of the present invention; Figure 13 A schematic diagram of the Pitch-Kick control logic provided for an embodiment of the present invention; Figure 14 A schematic diagram of the basic closed-loop shutdown control logic provided for an embodiment of the present invention; Figure 15 A schematic diagram of the control logic for unit startup provided in an embodiment of the present invention; Figure 16 A schematic diagram of the control logic for normal shutdown provided in an embodiment of the present invention; Figure 17 This is a schematic diagram of the emergency stop control logic provided for an embodiment of the present invention. Detailed Implementation

[0020] The features and exemplary embodiments of various aspects of this application will be described in detail below. To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain this application and not to limit it. For those skilled in the art, this application can be implemented without some of these specific details. The following description of the embodiments is merely to provide a better understanding of this application by illustrating examples.

[0021] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0022] To facilitate understanding, the relevant terms are explained below: Cut-in wind speed refers to the minimum ambient wind speed required for the unit to start up and operate stably. The cut-in speed n1 refers to the minimum stable speed that the wind turbine should reach before being integrated into normal power generation control; The pitch controller is used to adjust the pitch angle of the blades according to a predetermined pitch angular velocity; deg / s is a unit of angular velocity (degrees per second), used to limit the speed of pitch control. The rated speed is nr; Tip speed ratio (TSR) is the ratio of tip linear velocity to incoming air velocity, used to constrain the optimal aerodynamic efficiency trajectory; The optimal torque coefficient kopt is used to limit the maximum torque of the generator in the low wind speed range; The pitch controller is responsible for outputting the target pitch angle; The torque controller achieves closed-loop stability of speed and power by adjusting the electromagnetic torque of the generator.

[0023] like Figure 1 As shown, the present invention provides an operation control method for a vertical axis wind turbine, the operation control method for the vertical axis wind turbine includes: In step S11, during the unit startup phase, after releasing the mechanical brake of the wind turbine and confirming that the wind speed has reached the cut-in wind speed, the pitch angle of the blades is gradually increased to a preset angle by driving the pitch controller at a predetermined angular velocity to form a drag-type wind turbine to increase aerodynamic force. In step S12, when the wind turbine speed reaches the cut-in speed, the pitch angle of the lower blade is adjusted to the minimum pitch angle and maintained, and the optimal tip speed ratio is tracked until the wind turbine speed rises to the rated speed. In step S13, when the wind turbine speed reaches the rated speed, the wind turbine speed is stabilized at the rated speed, and the pitch angle of the lower blade is maintained at the minimum pitch angle until the generator output torque reaches the rated torque. In step S14, when the driving torque under the aerodynamic load continuously exceeds the rated torque of the generator and the generator speed reaches the warning speed threshold, the shutdown control strategy is triggered to increase the pitch angle of the lower blade to suppress the wind turbine speed and establish a closed-loop control between the wind turbine speed and the pitch angle to make the wind turbine enter a deceleration state. In step S15, under the shutdown control strategy, the pitch angle of the lower blade is continuously increased until the blade is fully retracted, and the generator torque is gradually reduced. After the wind turbine speed drops to the safe shutdown speed, the connection between the generator and the power grid is disconnected and a mechanical brake is applied to stop the wind turbine from rotating.

[0024] In one embodiment, to improve the aerodynamic efficiency and start-up / shutdown capability of vertical axis wind turbines and ensure the safety and stability of the units under different operating conditions, a systematic full-cycle operation control method is constructed. By introducing coordinated control mechanisms at each stage, including unit startup, normal power generation, fault response, and shutdown, the problems of complex operation control, strong startup dependence, and insufficient fault shutdown measures in existing technologies can be effectively solved. The vertical axis wind turbine structure on which this embodiment is based is as follows: Figure 9 As shown, the lower blades of this vertical axis wind turbine are equipped with a pitch actuator, which is driven by a pitch controller and can realize the full-process control of the wind turbine from startup, normal power generation to shutdown. The main structure of this vertical axis wind turbine includes: (1) The blades, as the main aerodynamic force providers, are divided into three parts: the upper blade (part 1), the middle blade (part 5), and the lower blade (part 8), which are connected by rigid connectors to reduce blade deformation and load during operation. Among them, the lower blade, in addition to providing aerodynamic force, is also the actuator for pitch control. Since the overall blade pitch control project is difficult to implement and has low reliability, and the pitch control mechanism is easier to maintain when it is closer to the lower end, the pitch control of the lower blade is used to achieve local pitch control of the vertical axis wind turbine for aerodynamic adjustment of the unit.

[0025] (2) The upper cross brace (part 3) and the lower cross brace (part 6) are mainly used to connect the blades and the hub (part 4). In order to reduce aerodynamic drag, airfoil-shaped fairings can be installed on the outside of the upper and lower supports.

[0026] (3) The main function of the rigid connecting parts (parts 2 and 7) is to connect the blades between different sections and the blades to the cross brace. The main function of rigid connecting part 2 is to connect the upper blade, the middle blade, and the upper support. The main function of rigid connecting part 7 is to connect the lower blade, the middle blade, and the lower support. At the same time, the pitch actuator is also installed at the location of part 7 and performs the pitching action through a worm gear mechanism. The structure of the pitch actuator is shown in the attached figure. Figure 10 As shown.

[0027] (4) The main bearing (component 10) is used to realize the rotation of the unit. The tower (component 9) is the main supporting component of the unit. The generator (component 11) is installed on the tower for the unit's power output and torque regulation.

[0028] This vertical axis wind turbine can achieve full-process control from start-up, normal power generation to shutdown, including the start-up phase, cut-in speed phase, rated speed cruise phase, overload warning phase, and shutdown deceleration phase, as shown in the attached diagram. Figure 11 As shown.

[0029] 1. Unit Start-up Phase. After releasing the mechanical brakes on the wind turbine and confirming that the ambient wind speed has reached the predetermined cut-in wind speed (i.e., the minimum wind speed at which the wind turbine can start and connect to the grid for power generation), the pitch controller is activated to gradually increase the pitch angle of the lower blades to a preset angle at a predetermined angular velocity. For example, in this embodiment, the lower blades rotate from their initial position to a pitch angle of approximately 90° at a speed of approximately 0.25 deg / s. By adjusting the pitch angle, the windward surface of the lower blades is increased, forming a drag-type wind turbine. This generates a larger drag torque through wind pressure to drive the wind turbine to rotate, thereby increasing the aerodynamic torque during the start-up phase and overcoming static resistance to allow the wind turbine to begin rotating slowly. Increasing the starting torque through pitch control effectively improves the problem of poor self-starting capability of traditional lift-type wind turbines.

[0030] 2. Cut-in Speed ​​Stage (Acceleration Stage). Once the wind turbine accelerates under wind power and reaches the unit's cut-in speed (the lowest speed at which the turbine begins to rotate stably and can drive the generator), the pitch angle of the lower blades is quickly adjusted back to the minimum pitch angle and maintained. Maximum aerodynamic efficiency is achieved when the lower blades are at the minimum pitch angle. After maintaining the minimum pitch angle, the control system begins to track the optimal tip speed ratio for acceleration control. The tip speed ratio λ is defined as the ratio of the linear velocity at the tip of the wind turbine blades to the current wind speed, i.e., λ = ωR / V, where ω is the angular velocity of the wind turbine, R is the blade radius, and V is the incoming wind speed. For a wind turbine, there exists an optimal tip speed ratio λ_opt such that the wind energy utilization coefficient C... p To reach its maximum value, the wind turbine maintains its rotor speed at the optimal tip speed ratio λ_opt as wind speed changes, ensuring it always captures energy from the wind with maximum efficiency, thus achieving maximum power point tracking. Therefore, during the acceleration process from the cut-in speed to the rated speed, the pitch controller keeps the lower blade at the minimum pitch angle, while adjusting the rotor acceleration through generator torque control, keeping the rotor operating near the optimal tip speed ratio until the rotor speed reaches the rated speed.

[0031] 3. Rated Speed ​​Cruise Phase. When the turbine speed increases and reaches the rated speed, the control system stabilizes the turbine speed at this rated speed. At this time, the pitch angle of the lower blades remains at the minimum pitch angle, and the turbine operates at its maximum aerodynamic power coefficient. As the wind speed further increases, the generator's output torque and power also increase. The turbine continues to operate at the rated speed until the generator's output torque reaches the unit's rated torque. In the normal power generation range at and below the rated wind speed, the control strategy is constant speed with variable torque. The aerodynamic torque is balanced by adjusting the generator's electromagnetic torque to keep the speed constant at the rated value while absorbing as much wind energy as possible. As the wind speed gradually increases from the cut-off value to the rated wind speed, the turbine can fully utilize wind energy to output power because the minimum pitch angle is maintained. When the wind speed reaches the rated wind speed, the generator reaches its rated power output, and the turbine enters a stable constant speed and constant power operation state. The control curves for turbine speed and power are shown in the attached figure. Figure 12 As shown.

[0032] 4. Overload Warning Stage: If the incoming wind speed increases and the aerodynamic load continues to exceed the rated operating conditions, for example, if the wind speed further increases causing the wind turbine to rotate at overspeed, the generator may already be operating at its rated torque or power limit and cannot balance the greater wind turbine driving force by increasing the electromagnetic torque. If the generator speed continues to rise and reaches a preset speed warning threshold, which is higher than the safety limit of the rated speed, a shutdown control strategy is immediately triggered. Under this shutdown control strategy, the pitch controller rapidly increases the pitch angle of the lower blades, yaws the blades towards the stall direction (i.e., retracts the blades) to increase the blade's angle of attack, thereby rapidly increasing aerodynamic drag to suppress the upward trend of the wind turbine speed. At the same time, the control system establishes a closed-loop control relationship between the wind turbine speed and the pitch angle, continuously adjusting the pitch angle opening based on the actual speed feedback, so that the wind turbine transitions from constant speed operation to a controlled deceleration state. Through the above closed-loop control, the pitch angle will automatically increase as the speed decelerates, forming negative feedback to reduce the wind turbine speed as quickly as possible, ensuring a smooth and controlled deceleration process. This overload warning stage marks the beginning of the wind turbine's protective shutdown process.

[0033] 5. Shutdown and Deceleration Phase. After implementing the shutdown control strategy described above, the pitch angle of the lower blades continues to gradually increase until the blades are fully retracted, reaching a 90° position where the blades are essentially parallel to the wind direction and bear almost no lift. In the fully retracted state, the aerodynamic torque on the rotor is significantly reduced, and the rotor will gradually decelerate using its own inertia and residual drag. Simultaneously, the control system gradually reduces the generator's electromagnetic torque, for example, by reducing the generator current according to a predetermined torque reduction slope, thus gradually weakening the electromagnetic damping of the generator on the rotor to avoid sudden torque changes causing shock. As the pitch angle is fully retracted and the generator torque decreases, the rotor speed will continue to decrease. When the rotor speed is detected to drop below the safe shutdown speed, i.e., below the speed at which mechanical braking can safely intervene, the control system disconnects the generator from the grid and then applies the mechanical brake to lock the rotor, ultimately stopping the rotor and completing the shutdown process. Through this phased shutdown control—first aerodynamic deceleration, then mechanical braking—the wind turbine can be safely and efficiently stopped under high wind or fault conditions, avoiding overspeed runaway and sudden stop impact.

[0034] The above-mentioned operation control method for vertical axis wind turbines realizes the automatic control of the entire process from start-up, normal operation to emergency shutdown of wind turbines, improves the self-starting and safe shutdown capabilities of vertical axis wind turbines, and takes into account the power output stability under various wind conditions.

[0035] To control the overall load level on the vertical axis and extend the wind speed adaptability range, the main load reduction techniques used are as follows: To control the overall load level of the vertical axis wind turbine and expand its wind speed adaptability range, this embodiment adopts the following load reduction technology: 1) Pitch-Kick technology: Based on the rotational speed, the current operating state of the unit is identified. In the corresponding state, an additional pitch angle is superimposed on the pitch control output to instantaneously increase aerodynamic drag and suppress overspeed. The Pitch-Kick control logic is shown in the attached figure. Figure 13 As shown.

[0036] 2) Closed-loop shutdown technology: A closed-loop relationship between engine speed and pitch angle is established. With engine speed reduction as the control target, the pitch is gradually reduced according to a predetermined pitch angle rate. This technology is activated under specific fault conditions, effectively reducing the ultimate load on the hub. The closed-loop shutdown control logic is shown in the attached figure. Figure 14 As shown.

[0037] The specific operating condition control logic is as follows: (1) Unit startup (speed n) <n1): When the unit is in standby preparation mode, the mechanical brake on the turbine is first released, and the ambient wind speed is checked to determine if it has reached the cut-in wind speed. Simultaneously, the unit completes a self-check. Then, the pitch controller drives the lower blades to gradually increase the pitch angle to 90° at a fixed pitch angular velocity of 0.25 deg / s, causing the lower blades to form a drag-type turbine, thereby increasing aerodynamic forces to assist in the turbine speed increase. The control logic for unit startup is shown in the attached figure. Figure 15 As shown.

[0038] (2) Normal power generation (speed n1) <n<nr) A) Control Zone I: Low Wind Speed Under low wind speed conditions, the reference speed of the pitch controller is set to the cut-in speed n1, and the maximum torque limit of the generator is limited by the optimal torque coefficient kopt to achieve optimal torque control. To further increase the rotor speed, the output of the pitch controller is adjusted to the minimum pitch angle and maintained at that position, thereby ensuring that the rotor obtains maximum aerodynamic power.

[0039] B) Control Zone II: Moderate wind speed Under medium wind speed conditions, the reference speed of the pitch controller is set to the rated speed nr. To ensure stability during the turbine acceleration process, the minimum output of the pitch controller is limited to the minimum pitch angle. When the rotor or generator speed reaches the rated speed nr, but the generator output power has not yet reached the power level of control zone III, the pitch controller continues to keep the lower blade at the minimum pitch angle to ensure that the turbine can maintain stable operation and gradually increase power output.

[0040] C) Control Zone III: High Wind Speed Under high wind speed conditions, the reference speed of the pitch controller is set to the rated speed nr. The generator torque is adjusted by the torque controller to maintain the turbine speed at the rated speed. At the same time, the pitch controller gradually adjusts the pitch angle of the lower blades to keep the output power within the preset power range, thereby ensuring the safe and stable operation of the unit under high wind speed conditions.

[0041] (3) Overspeed condition Generator speed sensors are installed on both the high-speed and low-speed shafts to monitor the unit's operating status in real time. When either sensor detects that the generator speed has reached a preset warning speed threshold, the control system triggers a normal shutdown strategy, thereby ensuring that the unit can enter a controlled shutdown process in a timely and safe manner before the risk of overspeed occurs.

[0042] (4) Power grid failure When the generator torque and grid output power drop to zero, the pitch system is activated to aerodynamically brake the wind turbine. The control system invokes the torque control strategy under normal shutdown conditions and gradually increases the pitch angle from the initial position according to the set pitch rate until the generator speed drops to the target shutdown speed, thereby achieving smooth deceleration and shutdown of the unit.

[0043] (5) Generator short circuit When a generator experiences a short circuit, its output torque increases sharply at the moment of the short circuit, significantly exceeding the generator torque under normal operating conditions, and then decays exponentially over the duration of the short circuit. Upon detecting the short circuit, the control system immediately activates the pitch system, gradually increasing the pitch angle of the lower blades to create aerodynamic drag, thereby effectively braking the wind turbine and preventing speed loss due to abnormal electromagnetic torque.

[0044] (6) Normal shutdown and emergency shutdown During a normal shutdown operation, the pitch controller first drives the blades to gradually increase the pitch angle to the normal shutdown position at a predetermined pitch angular velocity of 0.25 deg / s, preferably a 90° pitch angle. Then, the generator output torque is gradually reduced according to a reference descent slope, causing the generator speed to drop below the minimum operating speed threshold. Once the speed condition is met, the control system disconnects the generator from the grid and, after disconnection, engages the mechanical braking device to apply final braking to the turbine, ensuring a smooth and reliable shutdown of the unit. The control logic for normal shutdown is shown in the attached figure. Figure 16 As shown.

[0045] In an emergency shutdown scenario, the pitch control system drives the blades to gradually increase the pitch angle to the shutdown position at a speed of 0.75 deg / s. Subsequently, the control system gradually reduces the generator output according to a preset torque gradient, while simultaneously engaging the mechanical brakes. When the pitch angle reaches 90°, the brakes are released, and the full braking process begins. Once the generator speed drops below the minimum operating speed, the connection between the generator and the grid is disconnected, and the mechanical brakes are finally engaged, ensuring a rapid and safe shutdown of the wind turbine. The control logic for the emergency shutdown is shown in the attached figure. Figure 17 As shown.

[0046] This embodiment proposes a control method for the entire operation of a vertical axis wind turbine by adopting coordinated control of speed, torque, and local pitch, which can achieve the following beneficial effects: (1) Improve the start-up and shutdown capability of vertical axis wind turbines. During the start-up phase of the unit under low wind speed conditions, the pitch angle of the lower blades is adjusted by local pitch control to form a drag-type structure at the bottom of the rotor, thereby increasing the overall aerodynamic force of the unit and assisting in the increase of rotor speed, thus achieving a smooth start-up. This can effectively overcome the problem of insufficient self-starting capability of traditional lift-type vertical axis wind turbines and reduce the dependence on the motor system.

[0047] (2) Ensure stable power output. During normal power generation, the aerodynamic power output is increased under medium wind speed conditions and the unit load is reduced and the power is maintained under high wind speed conditions through coordinated control of speed, torque and pitch. This effectively solves the problem of large aerodynamic fluctuations in vertical axis wind turbines during operation and enhances the adaptability of the unit under different wind speed ranges.

[0048] (3) Ensure safety under fault conditions. Under fault or extreme wind speed conditions, the turbine speed and blade pitch angle are controlled in a coordinated manner by adopting Pitch-Kick technology and closed-loop shutdown technology, which effectively adjusts the overall load level of the unit and expands the wind speed adaptability range, thereby ensuring that the unit can achieve safe and reliable operation in different wind speed ranges and under various fault conditions.

[0049] (4) Enhance active start-stop capability. By setting a pitch drive mechanism on the lower rigid connecting member, partial pitch of the lower blades is achieved, enabling the wind turbine to form a drag-type operating mode under specific operating conditions. During the start-up phase, when the wind turbine speed is lower than the equilibrium speed, partial pitch can increase aerodynamic force, thereby improving the unit's start-up capability; under high-speed operating conditions, partial pitch increases aerodynamic drag, thereby reducing the generator torque required for braking and improving the unit's active shutdown performance.

[0050] The technical solution in this embodiment achieves smooth start-up of the wind turbine during the startup phase, stable operation at rated speed, and safe shutdown under fault conditions through partial pitch control and speed-torque coordinated control. Based on the feasibility of engineering implementation and operational reliability requirements, this embodiment employs a partial blade pitch mechanism, ensuring aerodynamic adjustment capabilities while maintaining high reliability and maintainability. By real-time identification of the wind turbine speed, the operating status of the unit is determined, and coordinated speed-torque-pitch control is executed under different states, thereby achieving the goals of reducing ultimate loads, maintaining stable power output under high wind speeds, and achieving safe shutdown under fault conditions. Furthermore, by adjusting the partial pitch to make part of the wind turbine a drag-type vertical axis wind turbine, the self-starting capability of the unit can be improved at low speeds, and the shutdown capability can be enhanced at high speeds. In summary, the technical solution in this embodiment effectively improves the unit's start-up and shutdown capabilities and power stability, expands the wind speed adaptability range, reduces ultimate loads, and ensures the safety and reliability of the unit throughout the entire operation process.

[0051] In one embodiment, such as Figure 2 As shown, it also includes the following steps S21-S23: In step S21, the mechanical brake of the wind turbine is released, and the start-up control is started after confirming that the wind speed has reached the cut-in wind speed and the unit self-test is normal. In step S22, the pitch angle of the lower blade is gradually increased to a preset angle by the pitch controller at a predetermined angular velocity to form a drag-type wind turbine, thereby increasing aerodynamic force to drive the wind turbine to rotate faster. In step S23, when the wind turbine speed rises to the cut-in speed, the startup process ends and the normal power generation operation phase begins.

[0052] In one embodiment, during the standby preparation state, the mechanical brake of the wind turbine is first released. The main control system then determines whether the ambient wind speed has reached the cut-in wind speed based on anemometer and wind vane data. Simultaneously, it completes self-checks and interlock checks. Self-check items include, but are not limited to: generator power unit and braking system readiness; normal power supply and communication status of the pitch drive mechanism; valid signals from the speed sensor and pitch angle sensor; no obstructions around the wind turbine; and temperature, humidity, and vibration thresholds within the tower within permissible ranges. Only when all the above conditions are met does the control system enter the startup control step to ensure the safety and controllability of the startup process.

[0053] The pitch controller is then activated, driving the lower blades to gradually increase the pitch angle at a fixed pitch angular velocity. In this embodiment, the pitch angle is preferably smoothly increased from the initial position to a preset angle at a rate of 0.25 deg / s, preferably 90°. As the pitch angle increases, the windward surface and drag component of the lower blades rise, and the lower half of the rotor transforms into a drag-type aerodynamic characteristic, thereby providing higher aerodynamic driving torque under low wind speed conditions, enabling the rotor to overcome static friction and transmission resistance to achieve start-up and acceleration. To avoid electromagnetic back torque inhibiting rotor acceleration, the generator adopts a current-limiting or low-torque mode during this stage, retaining only the minimum necessary electromagnetic damping to stabilize the acceleration process; simultaneously, the speed signal is collected to limit the amplitude and slope of the pitch angle increase, preventing local overload caused by transient gusts.

[0054] After the turbine speed climbs over time and reaches the cut-in speed n1, the control system determines that the start-up target has been achieved. It then terminates the drag-type start-up phase and switches to the preparation state for lift-type high-efficiency operation. The lower blade pitch angle is quickly and smoothly adjusted from the preset angle to the minimum pitch angle and maintained, restoring the blade lift coefficient and wind energy utilization coefficient to a range conducive to efficient energy capture. Simultaneously, the main controller sets the control target to track the optimal tip speed ratio (TSR). That is, in the subsequent acceleration phase, torque control is used to keep the turbine operating near the optimal tip speed ratio λ_opt to achieve maximum power point tracking. As the speed further increases and approaches the rated speed nr, it gradually transitions to constant speed control and, in conjunction with PI regulation, stabilizes at the rated point, thus laying the initial conditions for entering normal power generation operation.

[0055] If the wind speed drops below the cut-in wind speed for a duration exceeding the preset time during pitch angle adjustment, or if the speed increase rate is lower than the threshold, the control system will maintain the current pitch angle and enter a wind observation delay. If the conditions are still not met after the delay, the pitch angle will be adjusted back to the safe angle according to the predetermined slope and the mechanical brake will be reapplied, terminating the start-up process. If a short-term gust of wind causes speed fluctuations when approaching n1, the oscillation will be suppressed by limiting the pitch angular velocity and cooperating with the generator's slight damping until the speed stably crosses the criterion window of n1, and then the control phase will be switched.

[0056] In summary, the technical solution in this embodiment enables reliable self-starting of vertical axis wind turbines under low wind speed conditions, reduces dependence on the motor system, and achieves feasibility and ease of maintenance with minimal structural modifications.

[0057] In one embodiment, such as Figure 3 As shown, it also includes the following steps S31-S33: In step S31, under low wind speed conditions, the reference speed of the pitch controller is set to the cut-in speed, and the maximum torque output of the generator is limited by the optimal torque coefficient. At the same time, the pitch angle of the lower blade is kept at the minimum pitch angle to maximize aerodynamic power and promote the continuous acceleration of the wind turbine. In step S32, under medium wind speed conditions, the reference speed of the pitch controller is switched to the rated speed, and the pitch angle of the lower blade is maintained at the minimum pitch angle. When the wind turbine speed reaches the rated speed but the generator output power has not yet reached the rated power, the generator output is increased to increase the wind turbine output power. In step S33, under high wind speed conditions, the wind turbine speed is stabilized at the rated speed by generator torque control, and the pitch angle of the lower blade is gradually increased by the pitch controller to limit the wind turbine output power within the rated power range for smooth operation.

[0058] In one embodiment, the control system divides the operating range into three conditions—low wind speed, medium wind speed, and high wind speed—based on wind speed, rotational speed, and power feedback, and sets corresponding switching criteria and parameter limits to ensure stable power, controllable load, and continuous transition.

[0059] In low wind speed conditions, the goal is to improve aerodynamic efficiency and promote turbine acceleration. The reference speed of the pitch controller is set to the cut-in speed n1. The maximum electromagnetic torque of the generator is limited by the optimal torque coefficient kopt to avoid excessive electromagnetic damping that inhibits speed rise. Simultaneously, the lower blade is kept at the minimum pitch angle, placing it in the lift-type high-efficiency range to maximize aerodynamic power. Torque control is used to accelerate along the optimal tip speed ratio (TSR) trajectory, and PI tracking and pre-filtering are used to reduce the impact of disturbances on the speed, allowing the speed to smoothly approach the rated speed nr without significant overshoot.

[0060] Upon entering the medium wind speed operating condition, the reference speed of the pitch controller is switched to the rated speed nr, and the minimum pitch angle of the lower blade is maintained. If the speed has stabilized at the rated speed nr but the generator output power is still lower than the rated power, the electromagnetic torque is gradually increased according to the set slope until the rated value is reached. To avoid frequent switching and low-frequency oscillations near the rated speed nr, a speed dead zone and duration threshold are set, and anti-saturation treatment is adopted for the integral circuit to make the power compensation process continuous and controllable.

[0061] In high wind speed conditions, the control objective shifts to power limiting and load reduction. The pitch controller maintains its reference speed at the rated speed (nr), while the torque controller stabilizes the speed. As wind speed increases, the pitch controller, based on rate limits and up / down slope constraints, gradually increases the pitch angle of the lower blades, reducing lift and increasing aerodynamic drag, thus keeping the unit's output power within the rated power range. This ensures both the upper power limit and grid connection stability, while effectively suppressing peak loads on the blades, hub, and drivetrain, delaying fatigue accumulation and improving overall reliability. When wind speed decreases or power deviates from the preset range, the electromagnetic torque is adjusted first according to priority, then the pitch angle is smoothly adjusted back to ensure a smooth transition back to medium or low wind speed conditions. If the measured operating speed exceeds the warning threshold of the rated speed (nr) or an abnormal disturbance occurs, the protection process is initiated according to the higher-level strategy.

[0062] In one embodiment, such as Figure 4 As shown, it also includes the following steps S41-S43: In step S41, when the wind turbine speed or generator speed is detected to reach the warning speed threshold, or when a power grid fault causes the generator to lose load, overspeed suppression control is immediately executed. By increasing the pitch angle of the lower blade, additional aerodynamic drag is applied to the wind turbine to suppress the speed from continuing to rise. The warning speed threshold is higher than the rated speed. In step S42, a closed-loop shutdown control strategy is initiated to establish a negative feedback control relationship between the wind turbine speed and the pitch angle. The pitch angle of the lower blade is continuously increased to the fully retracted position at a predetermined pitch angle velocity, while the generator torque is gradually reduced to gradually decrease the wind turbine speed. In step S43, when the wind turbine speed drops to the safe shutdown speed, the connection between the generator and the power grid is disconnected and a mechanical brake is applied to stop the wind turbine.

[0063] In one embodiment, for the shutdown process of the unit under fault or overspeed risk, a closed-loop control strategy based on the coordination of pitch control and torque control can ensure the safe deceleration and shutdown of the unit under abnormal conditions.

[0064] Fault Triggering and Overspeed Suppression. When the monitoring system detects that the rotor speed or generator speed has reached a preset warning speed threshold, which is higher than the rated speed to ensure early intervention of protection mechanisms, or when the generator loses load due to a power grid fault, the control system immediately enters protection mode. At this time, overspeed suppression control is executed first. The pitch controller rapidly increases the pitch angle of the lower blades, adding a certain increment to the original pitch command, causing the blades to gradually shift to a drag-type operating mode. The increased aerodynamic drag can weaken the rotor's acceleration trend in a short time, thus preventing the speed from continuing to rise and exceeding structural limits.

[0065] Closed-loop shutdown process. After completing the initial overspeed suppression action, the control system further activates the closed-loop shutdown control strategy. By real-time acquisition of the turbine speed, a negative feedback relationship is established between the turbine speed and the pitch angle. When the speed is too high, the pitch angle is automatically increased; when the speed decreases and stabilizes, the increase in the pitch angle slows down accordingly. Throughout the process, the pitch angle of the lower blades continuously increases at a preset pitch rate until it reaches the fully retracted position, preferably 90°. Simultaneously, the generator torque gradually decreases according to a reference descent slope to avoid system shock caused by sudden changes in electromagnetic damping. This allows the turbine to gradually reduce its speed with a smooth deceleration trajectory, without drastic fluctuations.

[0066] Safe shutdown and mechanical braking. As the turbine speed gradually decreases and falls below the set safe shutdown speed, the control system disconnects the generator from the grid to prevent reverse power flow or unstable power input. Simultaneously, the turbine's mechanical braking system is activated to completely release the remaining rotational inertia, ensuring the turbine comes to a complete stop. This phased strategy of first using pneumatic control and then mechanical braking not only avoids mechanical shock caused by sudden stopping but also reduces the ultimate load on the hub and drivetrain.

[0067] The technical solution in this embodiment enables the controllable shutdown of vertical axis wind turbines under fault conditions. It has the advantages of fast response, smooth deceleration, and controllable load, and is especially suitable for complex conditions such as sudden wind speed changes, power grid faults, and generator short circuits.

[0068] In one embodiment, such as Figure 5 As shown, it also includes the following steps S51-S53: In step S51, the vertical axis wind turbine adopts a segmented blade structure design, consisting of an upper blade, a middle blade, and a lower blade connected in sequence by rigid connectors. In step S52, the lower blade is equipped with a pitch drive mechanism, which drives the lower blade to rotate around its longitudinal axis through worm gear transmission to change the pitch angle. In step S53, the aerodynamic power of the wind turbine is controlled by adjusting the pitch angle of the lower blade.

[0069] In one embodiment, the vertical axis wind turbine adopts a segmented blade structure. The upper, middle, and lower blades are sequentially connected by rigid connectors and form an integral load-bearing frame with the upper / lower cross braces and hub. A pitch actuator is integrated at the lower rigid connector, preferably a motor-worm gear transmission: the motor output, after reduction, drives the worm gear, which in turn rotates the meshing worm wheel around the longitudinal axis of the blade, thus adjusting the pitch angle of the lower blade. The worm gear's self-locking characteristic ensures that the current pitch angle is maintained even under power failure or impact loads. Combined with an angle encoder, mechanical limit switches, and electrical travel switches, a closed-loop position and extreme safety redundancy are formed. To reduce additional aerodynamic drag and rain / fog erosion, the actuator and transmission components are housed within a streamlined lower fairing. The interfaces feature protective seals and maintainable quick-release structures for easy on-site maintenance and replacement.

[0070] At the control level, the lower blade, as the sole pitch actuator, receives pitch angle commands from the pitch controller and executes them at predetermined pitch angular velocities (preferably 0.25 deg / s for normal shutdown and 0.75 deg / s for emergency shutdown). In low wind speeds, the system maintains the pitch angle at its minimum to achieve lift-type efficient operation; during startup or overspeed suppression, it increases the pitch angle as instructed, causing some blades to switch to drag-type operation to increase aerodynamic drag or starting torque. Thus, aerodynamic torque control is achieved using pitch angle adjustment as a single input channel, forming a coordinated control chain of speed-torque-pitch with generator torque control. In low wind speeds, torque is limited and the minimum pitch angle is used to accelerate to rated speed; in medium wind speeds, constant speed power compensation is implemented; in high wind speeds, the pitch angle is gradually increased under constant speed conditions to limit power and reduce load. To suppress coupled oscillations, pitch commands employ rate limiting, different up and down slopes, and small signal dead zones; to ensure positioning accuracy, the angle closed loop incorporates pre-filtering and anti-integral saturation strategies.

[0071] In terms of engineering implementation and calibration, the pitch angle travel preferably covers the range from the minimum pitch angle to 90° pitch retraction. During startup, the pitch angle is smoothly increased from the minimum to approximately 90° to form a drag-type rotor. During normal power generation, the minimum pitch angle is maintained to maximize aerodynamic efficiency. When the warning speed threshold is triggered or a power grid fault / generator short circuit occurs, a closed-loop shutdown process is entered. The pitch is continuously retracted to 90° at a predetermined pitch rate, and the electromagnetic torque is simultaneously reduced by the slope. After the speed drops to the safe shutdown threshold, the system disconnects and engages the mechanical brake to achieve a smooth shutdown. To improve reliability, the pitch drive link is equipped with temperature rise and current monitoring, out-of-step detection, and fault return-to-zero logic. Once an abnormal position or drive overload is detected, the system will retract the pitch to a safe position at a limited rate and simultaneously issue an alarm signal. The technical solution in this embodiment can ensure effective regulation of aerodynamic power by the lower blade pitch, and provide a consistent execution interface and safety interlocks in each stage of startup, normal power generation, and fault shutdown.

[0072] In one embodiment, such as Figure 6As shown, it also includes the following steps S61-S63: In step S61, the current operating condition of the unit is identified by real-time monitoring of the wind turbine speed. Under the unit startup condition, the startup acceleration capability of the wind turbine is improved by local pitch adjustment in conjunction with generator torque regulation. In step S62, under normal power generation conditions, the pitch angle of the lower blade and the torque output of the generator are adjusted in coordination according to the wind speed range to improve the aerodynamic power output at medium wind speeds, reduce the wind turbine load at high wind speeds, and maintain stable output power. In step S63, under fault shutdown conditions, the turbine speed is rapidly reduced by combining the Pitch-Kick technology and closed-loop shutdown control strategy to ensure safe shutdown of the unit. The Pitch-Kick technology refers to a control strategy that achieves rapid speed reduction by superimposing an additional pitch angle on the pitch control output.

[0073] In one embodiment, by employing differentiated control strategies at different operational stages, safe and stable operation of the wind turbine is achieved throughout the entire process from startup and normal power generation to fault shutdown. The turbine rotational speed is used as the monitoring quantity to determine whether the unit is in startup, power generation, or fault condition, and based on this, local pitch control and generator torque control are dynamically activated to achieve aerodynamic power regulation and operational state switching.

[0074] During the turbine startup phase, the rotor speed is low and has not yet reached the cut-in speed. At this time, relying solely on the electromagnetic torque provided by the generator is often insufficient to overcome static friction and transmission resistance, resulting in inadequate self-starting performance. This embodiment, by monitoring the rotor speed in real time and confirming that the turbine is in startup condition, implements a local pitch and torque coordination strategy. The pitch angle is gradually increased by the pitch drive mechanism of the lower blades, creating a drag-type characteristic at the bottom of the rotor, thereby increasing overall aerodynamic force and enhancing the rotor's starting torque. Simultaneously, the generator control system operates in a limited torque mode, providing only a small amount of electromagnetic damping to avoid inhibiting the acceleration process. The rotor can achieve smooth acceleration under low wind speed conditions until the speed reaches the cut-in speed n1, successfully entering the normal power generation operating range.

[0075] When the turbine speed exceeds the cut-in speed and gradually stabilizes, the control system determines that the unit has entered normal power generation conditions based on wind speed and speed feedback. In the low wind speed range, the system maintains the minimum pitch angle of the lower blades, operating in lift mode. The optimal torque coefficient kopt is used to limit the maximum generator torque, ensuring the turbine accelerates along the optimal tip speed ratio trajectory and improving aerodynamic efficiency. In the medium wind speed range, when the turbine speed approaches the rated speed nr, the pitch controller switches the reference speed to nr, and the blades continue to maintain the minimum pitch angle. If the generator output power has not yet reached the rated power, the electromagnetic torque is gradually increased until the power is compensated. In the high wind speed range, when the wind speed exceeds the rated wind speed, the torque controller maintains stable turbine operation near nr, while the pitch controller gradually increases the pitch angle of the lower blades to limit power within the rated range, while simultaneously reducing the peak load on the blades and drive train. The unit can achieve efficient and stable power output under different wind speed conditions.

[0076] When the wind turbine or generator speed exceeds the warning threshold, or when abnormal conditions such as grid faults or generator short circuits occur, the system automatically identifies and enters a fault shutdown mode. At this time, the control strategy switches from normal power generation to rapid deceleration and safe shutdown. First, using Pitch-Kick technology, an additional pitch angle is superimposed on the existing pitch angle command, rapidly increasing aerodynamic drag on the wind turbine to curb overspeeding. Then, a closed-loop shutdown process is initiated, establishing a negative feedback relationship between the wind turbine speed and the pitch angle, causing the pitch angle to gradually decrease to the full pitch position as the speed feedback occurs, while simultaneously reducing generator torque according to a reference gradient. When the wind turbine speed drops below the safe shutdown threshold, the control system disconnects the generator from the grid and engages the mechanical brakes, ultimately achieving a complete stop of the wind turbine. This ensures that the unit can shut down quickly and safely under fault or extreme wind speed conditions, avoiding damage to the unit structure caused by overspeed and load impacts.

[0077] By monitoring the wind turbine speed in real time, the operating conditions of the unit are accurately identified, and coordinated control of partial pitch and generator torque is implemented during startup, normal power generation, and fault shutdown. This enhances the self-starting capability at low wind speeds, maintains stable power output during normal operation, and rapidly reduces the speed during fault shutdown, thereby improving the safety and adaptability of the unit throughout the entire operation process.

[0078] In one embodiment, Figure 7 This is a block diagram illustrating an operation control device for a vertical axis wind turbine according to an exemplary embodiment. Figure 7 As shown, the operation control device of the vertical axis wind turbine includes a start module 71, an adjustment module 72, a stabilization module 73, a deceleration module 74, and a stop module 75.

[0079] The start-up module 71 is used to release the mechanical brake of the wind turbine and confirm that the wind speed has reached the cut-in wind speed during the start-up phase of the unit. Then, through the pitch controller, the pitch angle of the blades is gradually increased to a preset angle at a predetermined angular velocity to form a drag-type wind turbine to increase aerodynamic force. The adjustment module 72 is used to adjust the pitch angle of the lower blade to the minimum pitch angle and maintain it after the wind turbine speed reaches the cut-in speed, and to track the optimal tip speed ratio until the wind turbine speed rises to the rated speed. The stabilization module 73 is used to stabilize the wind turbine speed at the rated speed when the wind turbine speed reaches the rated speed, and maintain the pitch angle of the lower blade at the minimum pitch angle until the generator output torque reaches the rated torque. The deceleration module 74 is used to trigger a shutdown control strategy when the driving torque under aerodynamic load continuously exceeds the rated torque of the generator and the generator speed reaches the warning speed threshold. This strategy increases the pitch angle of the lower blade to suppress the wind turbine speed and establishes a closed-loop control between the wind turbine speed and the pitch angle to make the wind turbine enter a deceleration state. The stop module 75 is used to continuously increase the pitch angle of the lower blade until it is fully retracted under the shutdown control strategy, and gradually reduce the generator torque. After the wind turbine speed drops to the safe shutdown speed, the generator is disconnected from the grid and a mechanical brake is applied to stop the wind turbine from rotating.

[0080] The start-up module 71, adjustment module 72, stabilization module 73, deceleration module 74, and stop module 75 included in the block diagram of the operation control device for a vertical axis wind turbine are controlled to execute the operation control method for a vertical axis wind turbine described in any of the above embodiments.

[0081] like Figure 8 As shown, the present invention provides an electronic device 800, which includes: a communication interface, a processor 801, and a memory 802; The memory 802 stores program instructions. When executed by the processor 801, which is connected to the memory 802 via the communication interface, the program instructions, during the unit startup phase, release the mechanical brake on the wind turbine and confirm that the wind speed has reached the cut-in wind speed. Then, through the pitch controller, the pitch angle of the lower blades is gradually increased to a preset angle at a predetermined angular velocity to form a drag-type wind turbine and increase aerodynamic force. When the wind turbine speed reaches the cut-in speed, the pitch angle of the lower blades is adjusted to the minimum pitch angle and maintained, tracking the optimal tip speed ratio until the wind turbine speed rises to the rated speed. When the wind turbine speed reaches the rated speed, the wind turbine speed is stabilized at the rated speed. The generator speed is maintained at the minimum pitch angle until the generator output torque reaches the rated torque. When the driving torque under aerodynamic load continuously exceeds the rated torque of the generator and the generator speed reaches the warning speed threshold, a shutdown control strategy is triggered. The pitch angle of the lower blade is increased to suppress the rotor speed, and a closed-loop control between the rotor speed and the pitch angle is established to make the rotor enter a deceleration state. Under the shutdown control strategy, the pitch angle of the lower blade is continuously increased until the blades are fully retracted, and the generator torque is gradually reduced. After the rotor speed drops to the safe shutdown speed, the connection between the generator and the grid is disconnected and a mechanical brake is applied to stop the rotor from rotating.

[0082] This invention provides a computer-readable storage medium storing computer program instructions. When the computer program instructions are executed by a processor, during the unit startup phase, after releasing the mechanical brake of the wind turbine and confirming that the wind speed has reached the cut-in wind speed, the pitch angle of the lower blades is gradually increased to a preset angle via a pitch controller at a predetermined angular velocity, forming a drag-type wind turbine to increase aerodynamic force. Once the wind turbine speed reaches the cut-in speed, the pitch angle of the lower blades is adjusted to the minimum pitch angle and maintained, tracking the optimal tip speed ratio until the wind turbine speed rises to the rated speed. When the wind turbine speed reaches the rated speed, the wind turbine speed is stabilized at the rated speed, and... The pitch angle of the lower blade is maintained at the minimum pitch angle until the generator output torque reaches the rated torque. When the driving torque under aerodynamic load continuously exceeds the rated torque of the generator and the generator speed reaches the warning speed threshold, a shutdown control strategy is triggered to increase the pitch angle of the lower blade to suppress the wind turbine speed and establish a closed-loop control between the wind turbine speed and the pitch angle to make the wind turbine enter a deceleration state. Under the shutdown control strategy, the pitch angle of the lower blade is continuously increased until the blades are fully retracted, and the generator torque is gradually reduced. After the wind turbine speed drops to the safe shutdown speed, the connection between the generator and the grid is disconnected and a mechanical brake is applied to stop the wind turbine from rotating.

[0083] It should be understood that the specific features, operations, and details described above regarding the method of the present invention can also be similarly applied to the apparatus and system of the present invention, or vice versa. Furthermore, each step of the method of the present invention described above can be performed by a corresponding component or unit of the apparatus or system of the present invention.

[0084] It should be understood that the various modules / units of the device of the present invention can be implemented wholly or partially through software, hardware, firmware, or a combination thereof. Each module / unit can be embedded in the processor of a computer device in hardware or firmware form or independent of the processor, or it can be stored in the memory of a computer device in software form for the processor to call to execute the operation of each module / unit. Each module / unit can be implemented as an independent component or module, or two or more modules / units can be implemented as a single component or module.

[0085] In one embodiment, a computer device is provided, including a memory and a processor. The memory stores computer instructions executable by the processor, which, when executed by the processor, instruct the processor to perform steps of the methods of embodiments of the present invention. The computer device can be broadly categorized as a server, terminal, or any other electronic device with the necessary computing and / or processing capabilities. In one embodiment, the computer device may include a processor, memory, network interface, communication interface, etc., connected via a system bus. The processor of the computer device can be used to provide the necessary computing, processing, and / or control capabilities. The memory of the computer device may include a non-volatile storage medium and internal memory. The non-volatile storage medium may store an operating system, computer programs, etc. The internal memory can provide an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The network interface and communication interface of the computer device can be used to connect and communicate with external devices via a network. When the computer program is executed by the processor, it performs the steps of the methods of the present invention.

[0086] This invention can be implemented as a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, causes the steps of the methods of embodiments of the invention to be performed. In one embodiment, the computer program is distributed across multiple network-coupled computer devices or processors, such that the computer program is stored, accessed, and executed in a distributed manner by one or more computer devices or processors. A single method step / operation, or two or more method steps / operations, may be executed by a single computer device or processor or by two or more computer devices or processors. One or more method steps / operations may be executed by one or more computer devices or processors, and one or more other method steps / operations may be executed by one or more other computer devices or processors. One or more computer devices or processors may execute a single method step / operation, or execute two or more method steps / operations.

[0087] It will be understood by those skilled in the art that the method steps of the present invention can be performed by a computer program instructing related hardware, such as a computer device or processor. The computer program may be stored in a non-transitory computer-readable storage medium, and its execution causes the steps of the present invention to be performed. Depending on the context, any references herein to memory, storage, databases, or other media may include non-volatile and / or volatile memory. Examples of non-volatile memory include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), flash memory, magnetic tape, floppy disk, magneto-optical data storage device, optical data storage device, hard disk, solid-state drive, etc. Examples of volatile memory include random access memory (RAM), external cache memory, etc.

[0088] The technical features described above can be combined arbitrarily. Although not all possible combinations of these technical features are described, any combination of these technical features should be considered to be covered by this specification, provided that such combination does not contain contradictions.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method of operating a vertical axis wind turbine, characterized by, The application relates to a wind turbine starting control method and device. In the starting stage, the mechanical brake of the wind wheel is released, and the pitch angle of the lower blades is gradually increased to a preset angle by a predetermined angular velocity to form a resistance type wind wheel to increase the aerodynamic force; When the wind wheel speed reaches the cut-in speed, the pitch angle of the lower blades is adjusted to the minimum pitch angle and kept, and the optimal tip speed ratio is tracked until the wind wheel speed rises to the rated speed; When the wind wheel speed reaches the rated speed, the wind wheel speed is stabilized at the rated speed, and the pitch angle of the lower blades is kept at the minimum pitch angle until the generator output torque reaches the rated torque; When the driving torque under the aerodynamic load continuously exceeds the rated torque of the generator and the generator speed reaches a pre-warning speed threshold, a shutdown control strategy is triggered, the pitch angle of the lower blades is increased to suppress the wind wheel speed, and a closed-loop control of the wind wheel speed and the pitch angle is established to make the wind wheel enter a deceleration state; In the shutdown control strategy, the pitch angle of the lower blades is continuously increased to the fully closed position, and the generator torque is gradually reduced, and after the wind wheel speed drops to a safe shutdown speed, the generator is disconnected from the power grid and the mechanical brake is applied to stop the wind wheel.

2. The method of operating a vertical axis wind turbine generator as defined in claim 1, wherein, The starting stage includes: The mechanical brake of the wind wheel is released, and after it is confirmed that the wind speed reaches the cut-in speed and the unit self-check is normal, the starting control is started; The pitch angle of the lower blades is gradually increased to a preset angle by a predetermined angular velocity to form a resistance type wind wheel to increase the aerodynamic force to drive the wind wheel to rotate at high speed; When the wind wheel speed rises to the cut-in speed, the starting process is ended and the normal power generation operation stage is entered.

3. The method of operating a vertical axis wind turbine generator as defined in Claim 2 wherein, The control of the normal power generation operation stage includes: In the low wind speed working condition, the reference speed of the pitch controller is set as the cut-in speed, the maximum torque output of the generator is limited by the optimal torque coefficient, and the pitch angle of the lower blades is kept at the minimum pitch angle to maximize the aerodynamic power and promote the continuous acceleration of the wind wheel; In the medium wind speed working condition, the reference speed of the pitch controller is switched to the rated speed, and the pitch angle of the lower blades is kept at the minimum pitch angle, and when the wind wheel speed reaches the rated speed but the generator output power has not reached the rated power, the generator output is continuously increased to increase the wind wheel output power; In the high wind speed working condition, the wind wheel speed is stabilized at the rated speed by the generator torque control, and the pitch angle of the lower blades is gradually increased by the pitch controller to limit the wind wheel output power within the rated power range for smooth operation.

4. The method of operating a vertical axis wind turbine generator as defined in claim 3 wherein, Further includes: When it is monitored that the wind wheel speed or the generator speed reaches a pre-warning speed threshold or the generator loses the load due to a power grid fault, an overspeed suppression control is immediately executed, the pitch angle of the lower blades is increased to apply additional aerodynamic resistance to the wind wheel to suppress the continuous rise of the speed, and the pre-warning speed threshold is higher than the rated speed; A closed-loop shutdown control strategy is started, a negative feedback control relationship between the wind wheel speed and the pitch angle is established, the pitch angle of the lower blades is continuously increased to the fully closed position at a predetermined pitch angular velocity, and the generator torque is gradually reduced, so that the wind wheel speed gradually decreases. When the wind wheel rotation speed is reduced to the safe stop rotation speed, the generator is disconnected from the power grid and the mechanical brake is applied to brake and stop the wind wheel.

5. The method of operating a vertical axis wind turbine generator as defined in claim 1, wherein, Further comprising: The vertical axis wind turbine adopts a segmented blade structure design, in which the upper blade, the middle blade and the lower blade are connected in sequence through rigid connecting pieces; The lower blade is provided with a variable pitch driving mechanism, which drives the lower blade to rotate around its longitudinal axis to change the pitch angle through a worm gear transmission; The control of the aerodynamic power of the wind wheel is realized by adjusting the pitch angle of the lower blade.

6. The method of operating a vertical axis wind turbine generator as defined in claim 4 wherein, Further comprising: By real-time monitoring of the wind wheel rotation speed, the current operating condition of the unit is identified, and in the unit starting condition, the starting acceleration capability of the wind wheel at low wind speed is improved by local variable pitch combined with generator torque adjustment; In the normal power generation condition, the pitch angle of the lower blade and the torque output of the generator are cooperatively adjusted according to the wind speed interval to improve the aerodynamic power output at medium wind speed, reduce the wind wheel load at high wind speed and maintain stable output power; In the fault shutdown condition, the wind wheel rotation speed is quickly reduced by combining the Pitch-Kick technology and the closed-loop shutdown control strategy to ensure the safe shutdown of the unit, and the Pitch-Kick technology refers to a control strategy for achieving rapid speed reduction by superimposing an additional pitch angle on the pitch control output.

7. An operating control device for a vertical axis wind turbine, characterized by Comprising: A starting module for, in the unit starting phase, removing the mechanical brake of the wind wheel and confirming that the wind speed reaches the cut-in wind speed, then driving the pitch angle of the lower blade to gradually increase to a preset angle at a predetermined angular velocity through the pitch controller to form a resistance type wind wheel to increase the aerodynamic force; An adjusting module for, when the wind wheel rotation speed reaches the cut-in rotation speed, adjusting the pitch angle of the lower blade to the minimum pitch angle and keeping it, and tracking the optimal tip speed ratio until the wind wheel rotation speed rises to the rated rotation speed; A stabilizing module for, when the wind wheel rotation speed reaches the rated rotation speed, stabilizing the wind wheel rotation speed at the rated rotation speed and maintaining the pitch angle of the lower blade at the minimum pitch angle until the generator output torque reaches the rated torque; A deceleration module for, when the driving torque under the action of the aerodynamic load continuously exceeds the rated torque of the generator and the generator rotation speed reaches a pre-warning rotation speed threshold, triggering a shutdown control strategy, increasing the pitch angle of the lower blade to suppress the wind wheel rotation speed, and establishing a closed-loop control of the wind wheel rotation speed and the pitch angle to make the wind wheel enter a deceleration state; A stopping module for, under the shutdown control strategy, continuously increasing the pitch angle of the lower blade to full feathering and gradually reducing the generator torque, and after the wind wheel rotation speed is reduced to the safe stop rotation speed, disconnecting the generator from the power grid and applying the mechanical brake to stop the rotation of the wind wheel.

8. The operating control device of the vertical axis wind turbine generator as claimed in claim 7, wherein: The starting module, the adjusting module, the stabilizing module, the deceleration module and the stopping module are controlled to execute the operation control method of the vertical axis wind turbine according to any one of claims 1 to 6.

9. An electronic device, comprising: Comprising: A communication interface, a processor and a memory; The memory is used to store program instructions, and the program instructions, when executed by the processor in communication connection with the memory through the communication interface, cause the electronic device to implement the operation control method of the vertical axis wind turbine according to any one of claims 1 to 6.

10. A computer-readable storage medium having stored thereon program instructions, wherein, The program instructions, when executed by a computer, cause the computer to implement the operation control method of the vertical axis wind turbine according to any one of claims 1 to 6.

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