Power control method of blade tip rotating wind turbine

Abstract

The invention discloses a power control method of a blade tip rotating wind turbine, which is characterized in that the wind turbine is adapted to different weathers by controlling the convergent convergent mode of a blade tip convergent mechanism, when a wind speed sensor detects that the wind speed exceeds the rated wind speed, the wind turbine enters a typhoon mode, and a wind turbine controller drives a telescopic convergent rod to contract; the folded blade tip section is collected towards the blade section; when the wind speed is between the rated wind speed and the cut-out wind speed, the wind turbine enters a power adjusting mode, and a controller of the wind turbine dynamically adjusts the stroke of a telescopic convergent rod of a blade tip convergent mechanism according to a power error signal; the output power is stabilized by changing the effective wind sweeping area of the folding blade tip section; when the wind speed is reduced to a safety threshold value, the wind turbine enters a reset mode, a telescopic convergent rod of the blade tip convergent mechanism extends to the maximum stroke, and the continuous aerodynamic configuration of the blade is recovered; the windward strategies of the blade section and the folding blade tip section are respectively controlled through a control means, so that the purpose of power control is achieved.

Description

Technical Field

[0001] The invention relates to a power control method, in particular to a power control method for a blade tip rotating wind turbine. Background Art

[0002] Wind energy is an important renewable energy source. Since the 1870s, the number of wind turbines installed has increased rapidly. The size of wind turbines has increased significantly. One of the notable features of low-speed wind turbines is that they have longer blades to increase the swept area. At the same time, offshore wind power is also developing rapidly, and the urgent need to reduce the Cost of Energy (COE) of offshore wind power has driven the continuous increase in the length of wind turbine blades. The above two scenarios are a microcosm of the industry demand for the increasing diameter of wind turbine rotors. The power of a single wind turbine is expected to reach the 10-20 MW level, and the rotor diameter will increase to the range of 150-250 m.

[0003] With the comprehensive development of offshore and offshore wind turbines, and the trend of large-scale wind turbines, the adaptability of wind turbines to typhoons has gradually become a major problem hindering the development of wind energy. Typhoons are destructive to wind turbines. According to the performance indicators of large wind turbines and the current typhoon forecast regulations in my country, typhoons that land in my country can generally be divided into three categories: benefit type, defense type and destructive type: (1) Benefit type: affected by the outer periphery of the typhoon, the maximum wind force is below level 10; (2) Defensive type: affected by the outer periphery of the typhoon, the maximum wind force is between level 10 and 11; (3) Destructive type: affected by the outer periphery of the typhoon, the maximum wind force is above level 12. Typhoons that cause damage to wind turbines are generally destructive typhoons. According to statistics, there are three main types of damage caused by typhoons to wind turbines: overall overturning, tower failure and blade damage. Among the blade damage, the damage to the blade tip is particularly serious. Under large typhoons, even if the wind turbine is unloaded by variable pitch, there is still a lot of force at the blade tip, which damages the blade tip. There are already many ways to protect the blade tips during typhoons, but these designs still have problems when the wind turbines become large, so innovative designs must be made. At the same time, due to the large size of the blades, real-time pitch changes will also cause some damage to the wind turbine when the wind speed is above the rated power. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the prior art and provide a power control method for a blade tip rotating wind turbine, which adapts to different climates by controlling the convergence transformation of the blade tip convergence mechanism into multiple modes; the wind turbine blades are divided into a folding blade tip section and two ends of a blade segment, and in extreme weather such as typhoon weather, the blade tip is controlled to converge in the direction of the blade, so as to achieve the purpose of protecting the blade tip under the typhoon. At the same time, due to the separation of the folding blade tip section and the blade segment, the wind turbine can separately control the windward strategies of the blade segment and the folding blade tip section through control means to achieve the purpose of power control.

[0005] The object of the present invention is achieved by: a power control method for a blade tip rotating wind turbine, the wind turbine adapts to different climates by controlling the convergence transformation of the blade tip convergence mechanism to a plurality of modes; specifically comprising: When the wind speed sensor detects that the wind speed exceeds the rated wind speed, the wind turbine enters the typhoon mode, and the wind turbine controller drives the retractable convergence rod to converge the folded blade tip section toward the blade section; then the full blade is feathered 90°; the angle formed by the folded blade tip section and the blade section is A; When the wind speed is between the rated wind speed and the cut-out wind speed, the wind turbine enters the power regulation mode. The wind turbine controller dynamically adjusts the travel of the retractable convergence rod of the blade tip convergence mechanism according to the power error signal. The wind turbine controls the power of the wind turbine by controlling the angle A, so that the angle A varies within a certain range, and the output power is stabilized by changing the effective swept area of ​​the folded blade tip section. When the wind speed drops to the safety threshold, that is, the cut-out wind speed is reached, the wind turbine enters the reset mode, the retractable focusing rod of the blade tip focusing mechanism is extended to the maximum stroke, and the locking device locks the initial angle A of the blade to restore the continuous aerodynamic shape of the blade.

[0006] As a further limitation of the present invention, the blade tip convergence mechanism comprises a blade convergence support (1), a retractable convergence rod, a blade tip convergence support, a folding hinge, a blade segment, and a folding blade tip segment; one end of the blade convergence support is fixed to the blade segment, and the other end is hinged to one end of the retractable convergence rod; the other end of the retractable convergence rod is hinged to the blade tip convergence support, and the blade tip convergence support is fixed to the folding blade tip segment; the blade segment and the folding blade tip segment are connected by a folding hinge; the length of the folding blade tip segment is 15% to 25% of the total length of the blade, and an optical fiber strain sensor is pre-buried inside the folding blade tip segment to monitor stress distribution in real time; the folding hinge has a built-in electromagnetic damper to suppress flutter during the convergence process.

[0007] As a further limitation of the present invention, when the wind speed sensor detects a continuous wind speed ≥25 m / s, the wind turbine enters typhoon mode, and the blade tip convergence mechanism drives the retractable convergence rod through a hydraulic mechanism or a motor drive mechanism to adjust the angle A, so that the folded blade tip section converges toward the blade segment to an angle A≤45°, and then performs a 90° pitch change action to make the blade enter the feathering state.

[0008] As a further limitation of the present invention, the wind turbine enters a power regulation mode, and the controller of the wind turbine dynamically adjusts the stroke of the retractable focusing rod of the blade tip focusing mechanism according to the power error signal. The wind turbine controls the power of the wind turbine by controlling the angle A so that the angle A varies within the range of 60° to 120°.

[0009] As a further limitation of the present invention, the blade-on-blade convergence support and the blade-tip convergence support are both rotary hinge supports, and a bearing structure is provided inside.

[0010] As a further limitation of the present invention, the retractable retractable rod is at the minimum compression value when the wind turbine blades are in the retracted state, and the hydraulic latch locking device or the electromagnetic brake is activated to fix the retractable rod; when the wind turbine blades are in the unretracted state, the retractable rod is not completely fixed and has a certain movement margin, and power control is achieved by controlling the folding hinge to adjust the angle A.

[0011] The present invention adopts the above technical solution, and compared with the prior art, the beneficial effects are as follows: the blades of the wind turbine are divided into blade segments and folded blade tip segments, and the method of controlling the folded blade tip segments to converge controls the power and adapts the wind turbine to the typhoon climate; when a typhoon comes, the blade tip convergence mechanism will converge the folded blade tip segment to the blade segment, and the blade tip position of the wind turbine will be fully protected through the blade pitch function. In the case of blade tip convergence, the damage of the typhoon to the wind wheel will be reduced to a minimum. At the same time, due to the separation of the folded blade tip segment and the blade segment, the wind turbine can also realize the separation of the windward control of the blade segment and the folded blade tip segment at the rated wind speed, so that the entire wind turbine can stabilize the power by only controlling the smaller folded blade segment after the rated power, and can also minimize the damage to the blade tip under normal working conditions, and can also obtain greater efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the control process of the wind turbine implemented by the present invention; Figure 2 This is a front view of the blade tip of the present invention after convergence; Figure 3 It is a schematic diagram of different folded blade tip section positions and corresponding tangential force magnitudes of the present invention.

[0013] Among them, 1 is an upper convergence support, 2 is a telescopic convergence rod, 3 is a tip convergence support, 4 is a folding hinge, 5 is a blade segment, and 6 is a folding blade tip segment. DETAILED DESCRIPTION

[0014] like Figure 1 A power control method for a blade tip rotating wind turbine is shown, wherein the wind turbine adapts to different climates by controlling the blade tip convergence mechanism to change multiple modes, specifically including: When the wind speed sensor detects that the wind speed exceeds the rated wind speed, that is, when the continuous wind speed is ≥25 m / s, the wind turbine enters the typhoon mode, and the wind turbine controller drives the retractable convergence rod 2 to retract, so that the folded blade tip segment 6 converges toward the blade segment 5; then the full blade is feathered 90°; the angle formed by the folded blade tip segment 6 and the blade segment 5 is A; specifically, the blade tip convergence mechanism drives the retractable convergence rod 2 through a hydraulic mechanism or a motor drive mechanism to adjust the angle A, so that the folded blade tip segment 6 converges toward the blade segment 5 to an angle A≤45°; When the wind speed is between the rated wind speed and the cut-out wind speed, the wind turbine enters the power regulation mode, and the controller of the wind turbine dynamically adjusts the travel of the retractable convergence rod 2 of the blade tip convergence mechanism according to the power error signal. The wind turbine controls the power of the wind turbine by controlling the angle A, so that the angle A varies within the range of 60° to 120°, and the output power is stabilized by changing the effective swept area of ​​the folded blade tip section 6; When the wind speed drops to the safety threshold, that is, reaches the cut-out wind speed, the wind turbine enters the reset mode, the retractable focusing rod 2 of the blade tip focusing mechanism is extended to the maximum stroke, and the locking device locks the initial angle A of the blade to restore the continuous aerodynamic shape of the blade.

[0015] like Figure 2 As shown, the blade tip convergence mechanism includes a blade convergence support 1, a retractable convergence rod 2, a blade tip convergence support 3, a folding hinge 4, a blade segment 5, and a folding blade tip segment 6; one end of the blade convergence support 1 is fixed to the blade segment 5, and the other end is hinged to one end of the retractable convergence rod 2; the other end of the retractable convergence rod 2 is hinged to the blade tip convergence support 3, and the blade tip convergence support 3 is fixed to the folding blade tip segment 6; the blade segment 5 is connected to the folding blade tip segment 6 through a folding hinge 4; the length of the folding blade tip segment 6 is 15% to 25% of the total length of the blade, and an optical fiber strain sensor is pre-buried inside the folding blade tip segment 6 to monitor the stress distribution in real time; the folding hinge 4 has a built-in electromagnetic damper for suppressing flutter during the convergence process; the blade convergence support 1 and the blade tip convergence support 3 are both rotary hinge supports, and a bearing structure is provided inside to limit the horizontal and vertical displacement of the retractable convergence rod 2 and only allow rotation around the axis. The telescopic rod 2 is at its minimum compression value when the wind turbine blades are in the completed state of contraction. At this time, the hydraulic latch locking device or the electromagnetic brake is activated to fix the telescopic rod. When the wind turbine blades are in the uncontracted state, the telescopic rod is not completely fixed and has a certain movement margin. Power control is achieved by controlling the folding hinge 4 to adjust the angle A.

[0016] like Figure 3 As shown, when the folding tip section of a blade is in different folding shapes, the distribution of the tangential force per unit length of the corresponding blade changes greatly, indicating that the load and power of the blade can be adjusted by adjusting the folding tip section so that it can adapt to different climates.

[0017] The present invention provides a power control method for a blade tip rotating wind turbine, which adapts to different climates by controlling the convergence transformation of a blade tip convergence mechanism into multiple modes; the wind turbine blade is divided into a folding blade tip section and two ends of a blade segment, and in extreme weather such as typhoon weather, the blade tip is controlled to converge toward the blade direction, so as to achieve the purpose of protecting the blade tip under the typhoon, and at the same time, due to the separation of the folding blade tip section and the blade segment, the wind turbine can separately control the windward strategies of the blade segment and the folding blade tip section through control means, so as to achieve the purpose of power control.

[0018] The present invention is not limited to the above-mentioned embodiments. On the basis of the technical solution disclosed in the present invention, technicians in this field can make some substitutions and deformations to some technical features therein according to the disclosed technical content without creative labor, and these substitutions and deformations are all within the protection scope of the present invention.

Claims

1. A method for controlling the power of a blade tip rotating wind turbine, wherein the wind turbine adapts to different climates by controlling the blade tip convergence mechanism to change multiple modes, characterized in that: Specifically include: When the wind speed sensor detects that the wind speed exceeds the rated wind speed, the wind turbine enters the typhoon mode, and the wind turbine controller drives the retractable convergence rod (2) to retract, so that the folded blade tip section (6) converges toward the blade section (5); then the whole blade is feathered 90°; the angle formed by the folded blade tip section (6) and the blade section (5) is A; When the wind speed is between the rated wind speed and the cut-out wind speed, the wind turbine enters a power regulation mode, and the controller of the wind turbine dynamically adjusts the travel of the retractable convergence rod (2) of the blade tip convergence mechanism according to the power error signal. The wind turbine controls the power of the wind turbine by controlling the angle A, so that the angle A varies within a certain range, and the output power is stabilized by changing the effective swept area of ​​the folded blade tip section (6); When the wind speed drops to a safety threshold, i.e., reaches the cut-out wind speed, the wind turbine enters a reset mode, the retractable retracting rod (2) of the blade tip retracting mechanism is extended to the maximum stroke, and the locking device locks the initial blade angle A, thereby restoring the continuous aerodynamic shape of the blade.

2. A power control method for a blade tip rotating wind turbine according to claim 1, characterized in that: The blade tip convergence mechanism comprises a blade convergence support (1), a retractable convergence rod (2), a blade tip convergence support (3), a folding hinge (4), a blade segment (5), and a folding blade tip segment (6); one end of the blade convergence support (1) is fixed to the blade segment (5), and the other end is hinged to one end of the retractable convergence rod (2); the other end of the retractable convergence rod (2) is hinged to the blade tip convergence support (3), and the blade tip convergence support (3) is fixed to the folding blade tip segment (6); the blade segment (5) and the folding blade tip segment (6) are connected via the folding hinge (4); the length of the folding blade tip segment (6) is 15% to 25% of the total length of the blade, and an optical fiber strain sensor is pre-embedded in the folding blade tip segment (6) to monitor stress distribution in real time; the folding hinge (4) has a built-in electromagnetic damper to suppress flutter during the convergence process.

3. A power control method for a blade tip rotating wind turbine according to claim 2, characterized in that: When the wind speed sensor detects a continuous wind speed of ≥25 m / s, the wind turbine enters the typhoon mode, and the blade tip convergence mechanism drives the retractable convergence rod (2) through a hydraulic mechanism or a motor drive mechanism to adjust the angle A, so that the folded blade tip section (6) converges toward the blade section (5) to an angle A≤45°, and then performs a 90° pitch change action, so that the blade enters the feathering state.

4. A power control method for a blade tip rotating wind turbine according to claim 2, characterized in that: The wind turbine enters a power regulation mode, and the controller of the wind turbine dynamically adjusts the travel of the retractable convergence rod (2) of the blade tip convergence mechanism according to the power error signal. The wind turbine controls the power of the wind turbine by controlling the angle A, so that the angle A varies within the range of 60° to 120°.

5. The power control method of a blade tip rotating wind turbine according to claim 2, characterized in that: The blade-on-blade convergence support (1) and the blade-tip convergence support (3) are both rotary hinge supports, and a bearing structure is provided inside.

6. A power control method for a blade tip rotating wind turbine according to claim 2, characterized in that: The telescopic rod (2) is at its minimum compression value when the wind turbine blades are in a completed state of being retracted, at which time the hydraulic latch-type locking device or the electromagnetic brake is activated to fix the telescopic rod; when the wind turbine blades are in an unretracted state, the telescopic rod is not completely fixed and has a certain margin of motion, and power control is achieved by controlling the folding hinge (4) to adjust the angle A.

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