A method and system for reducing the load of a wind turbine

Abstract

The present invention discloses a method and a system for reducing the load of a wind turbine, which includes arranging a plurality of sensor strain gauges on the wind turbine blades and arranging two hydraulic cylinders inside the generator of the wind turbine; using the plurality of sensor strain gauges to measure the deformation of the blades in real time, and then calculating the magnitude and direction of the real-time wind load on the wind turbine blades according to the deformation; controlling the two hydraulic cylinders to apply thrust and reaction forces in the opposite directions to the generator housing and the gearbox housing respectively according to the magnitude and direction of the real-time wind load on the wind turbine blades, thereby generating two axial forces, and using the bending moments generated by the two axial forces respectively in the opposite direction of the wind load to offset the wind load, and finally realizing the reduction of the load on the top of the wind turbine tower. The present invention can effectively reduce the load on the top of the tower, and further achieve the purposes of reducing the weight of the tower and reducing the cost per kilowatt-hour of the wind turbine.

Description

Technical Field

[0001] The present invention relates to the technical field of wind turbines, and in particular to a method and a system for reducing the load of a wind turbine. Background Art

[0002] With the rapid development of wind power generation in China, wind turbines are gradually developing towards the trend of large-scale, and the cost per kilowatt-hour of the wind turbines is also continuously increasing. The key to reducing the cost per kilowatt-hour lies in the cost of the wind turbines. The tower barrel is an important part of the wind turbine, and its cost accounts for a large part of the total cost of the wind turbine. The weight of the tower barrel directly determines the cost of the wind turbine. The tower barrel mainly bears the load of the unit and transfers the load to the foundation. Under the condition that the external load of the wind turbine is determined, if a unit no longer transfers too much load to the tower barrel, the load-bearing requirement of the tower barrel can be reduced, and then the weight of the tower barrel can be reduced, so as to achieve the purpose of reducing the manufacturing cost of the tower barrel. At present, the load reduction technology for the tower barrel mainly reduces the load of the tower barrel by optimizing the controller or absorbing energy through a damper. These two methods both belong to indirect load reduction. Indirect load reduction is limited by indirect factors, which will cause a certain deviation between the expected load reduction amplitude of the tower barrel and the actual load reduction amplitude. At present, there is no method that can directly reduce the load at the top of the tower barrel. Summary of the Invention

[0003] The purpose of the present invention is to overcome the deficiencies of the prior art, and provide a method and a system for reducing the load of a wind turbine, which can effectively reduce the load at the top of the tower barrel, and then achieve the purpose of reducing the weight of the tower barrel and the cost per kilowatt-hour of the wind turbine.

[0004] The first purpose of the present invention is to provide a method for reducing the load of a wind turbine.

[0005] The second purpose of the present invention is to provide a system for reducing the load of a wind turbine.

[0006] The first purpose of the present invention can be achieved by adopting the following technical solutions:

[0007] A method for reducing the load of a wind turbine, comprising:

[0008] Arranging a plurality of sensor strain gauges at the tip, middle and root positions of the wind turbine blade respectively, and arranging two hydraulically actuated cylinders connected in series inside the generator of the wind turbine, wherein one hydraulically actuated cylinder is fixed on the side wall of the gearbox housing inside the generator, and the piston rod of the other hydraulically actuated cylinder abuts against the inner wall of the generator housing;

[0009] Using the plurality of sensor strain gauges to measure the deformation amounts of the blade tip, middle and root in real time, and then calculating the magnitude and direction of the real-time wind load of the wind turbine blade according to the deformation amounts measured in real time;

[0010] According to the magnitude and direction of the real-time wind load on the wind turbine blade, two hydraulic cylinders are controlled to apply thrust and reaction forces in the opposite directions to the generator housing and the gearbox housing respectively, thereby generating two axial forces. The bending moments opposite to the wind load direction generated by the two axial forces are used to offset the wind load, and finally the reduction of the tower top load of the wind turbine is achieved.

[0011] Furthermore, before the on-site hoisting of the wind turbine blade, multiple sensor strain gauges are respectively arranged at the corresponding positions of the blade tip, blade middle, and blade root. By calibrating the multiple sensor strain gauges, the relationship between the deformation of the sensor strain gauges and the external load of the blade is obtained.

[0012] Furthermore, the two hydraulic cylinders are respectively a first hydraulic cylinder and a second hydraulic cylinder. The rodless cavity of the first hydraulic cylinder is vertically connected to the rodless cavity of the second hydraulic cylinder. The first hydraulic cylinder is fixed on the side wall of the gearbox housing, and the piston rod of the second hydraulic cylinder vertically abuts against the inner wall of the generator housing.

[0013] The second object of the present invention can be achieved by adopting the following technical solutions:

[0014] A wind turbine load reduction system is applied to the above-mentioned wind turbine load reduction method, and includes a sensor module, a data processing module, a load reduction module, and a control module. The sensor module includes multiple sensor strain gauges, and the multiple sensor strain gauges are respectively arranged at the blade tip, blade middle, and blade root positions of the wind turbine blade for real-time measuring the deformation of the blade tip, blade middle, and blade root. The data processing module is communicatively connected to the sensor module for calculating the magnitude and direction of the real-time wind load on the wind turbine blade according to the real-time measured deformation. The load reduction module includes two hydraulically connected cylinders arranged inside the generator of the wind turbine. One of the hydraulic cylinders is fixed on the side wall of the gearbox housing inside the generator, and the piston rod of the other hydraulic cylinder abuts against the inner wall of the generator housing. The control module is communicatively connected to the data processing module for controlling the two hydraulic cylinders to apply thrust and reaction forces in the opposite directions to the generator housing and the gearbox housing respectively according to the magnitude and direction of the real-time wind load on the wind turbine blade, thereby generating two axial forces. The bending moments opposite to the wind load direction generated by the two axial forces are used to offset the wind load, and finally the reduction of the tower top load of the wind turbine is achieved.

[0015] Furthermore, the two hydraulic cylinders are respectively a first hydraulic cylinder and a second hydraulic cylinder. The rodless cavity of the first hydraulic cylinder is vertically connected to the rodless cavity of the second hydraulic cylinder. The first hydraulic cylinder is fixed on the side wall of the gearbox housing, and the piston rod of the second hydraulic cylinder vertically abuts against the inner wall of the generator housing.

[0016] Furthermore, 2 sensor strain gauges are respectively arranged at each position of the blade tip, blade middle, and blade root.

[0017] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0018] The present invention adopts a direct load reduction method, that is, first calculates the real-time wind load of the fan blade through the sensor strain gauge, and then offsets the wind load by applying the real-time load in the opposite direction through two hydraulically actuated cylinders connected in series arranged inside the generator, so as to achieve the purpose of reducing the load on the top of the tower barrel, and further achieve the purpose of reducing the weight of the tower barrel. After the weight of the tower barrel is reduced, the cost per kilowatt-hour of the wind turbine also decreases, greatly improving the competitiveness of the fan. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is the principle of the load reduction system of the present invention Figure 1 .

[0020] Figure 2 is the principle of the load reduction system of the present invention Figure 2 .

[0021] Figure 3 is the structural schematic diagram of the load reduction system of the present invention.

[0022] Figure 4 is the external view of the load reduction module of the present invention.

[0023] Figure 5 is the internal structure schematic of the load reduction module of the present invention Figure 1 .

[0024] Figure 6 is the internal structure schematic of the load reduction module of the present invention Figure 2 .

[0025] Figure 7 is the force deformation diagram of the sensor strain gauge of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0027] Such as Figures 1 to 6As shown in the figure, this embodiment provides a load reduction system for a wind turbine, which includes a sensor module, a load reduction module, a data processing module, and a control module. The sensor module includes a plurality of sensor strain gauges 1, which are respectively arranged at the tip, middle, and root positions of the wind turbine blade for real-time measurement of the deformation of the blade tip, middle, and root. The data processing module is communicatively connected to the sensor module and is used to calculate the magnitude and direction of the real-time wind load on the wind turbine blade according to the real-time measured deformation. The load reduction module includes two hydraulically actuators connected in series. The two hydraulically actuators are arranged inside the generator of the wind turbine. One hydraulically actuator is fixed on the side wall of the gearbox housing 5 inside the generator, and the piston rod of the other hydraulically actuator abuts against the inner wall of the generator housing 4. The control module is communicatively connected to the data processing module and is used to control the two hydraulically actuators to apply a thrust and a reaction force in the opposite direction to the generator housing 4 and the gearbox housing 5 respectively according to the magnitude and direction of the real-time wind load on the wind turbine blade, so as to generate two axial forces, and generate bending moments opposite to the wind load direction through the two axial forces to offset the wind load, and finally reduce the load on the top of the wind turbine tower.

[0028] Specifically, 2 sensor strain gauges 1 are respectively arranged at each of the tip, middle, and root positions of the blade.

[0029] Specifically, the two hydraulically actuators are respectively a first hydraulically actuator 2 and a second hydraulically actuator 3. The rodless chambers of the first hydraulically actuator 2 and the second hydraulically actuator 3 are vertically connected. The first hydraulically actuator 2 is fixed on the side wall of the gearbox housing 5, and the piston rod 303 of the second hydraulically actuator 3 vertically abuts against the inner wall of the generator housing 4.

[0030] The load reduction principle is specifically as follows: Hydraulic oil is injected through the oil inlet 201 of the first hydraulically actuator 2, then input to the oil inlet 301 of the second hydraulically actuator 3 through the oil outlet 202 of the first hydraulically actuator 2, and then flows out through the oil outlet 302 of the second hydraulically actuator 3. The pressure generated by the oil pressure is converted into a thrust acting on the generator housing 4 on the one hand, generating an axial force to resist the wind turbine bending moment, and on the other hand, acting on the gearbox housing 5 through the reaction force, and this reaction force will also generate an axial force, and this axial force will also generate an axial force to resist the wind turbine bending moment. The direction of the force is as shown by the arrow in Figure 2 The bending moments opposite to the wind load direction are generated through the two axial forces to offset the wind load, and finally the load on the top of the wind turbine tower is reduced.

[0031] This embodiment also provides a method for reducing the load of a wind turbine, including:

[0032] A plurality of sensor strain gauges are respectively arranged at the tip, middle and root positions of the wind turbine blade. Two hydraulically actuated cylinders connected in series are arranged inside the generator of the wind turbine. One of the hydraulically actuated cylinders is fixed to the side wall of the gearbox housing inside the generator, and the piston rod of the other hydraulically actuated cylinder abuts against the inner wall of the generator housing;

[0033] A plurality of sensor strain gauges are used to measure the deformation of the blade tip, middle and root in real time, and then the magnitude and direction of the real-time wind load on the wind turbine blade are calculated according to the measured deformation;

[0034] According to the magnitude and direction of the real-time wind load on the wind turbine blade, the two hydraulically actuated cylinders are controlled to apply thrust and reaction forces in the opposite directions to the generator housing and the gearbox housing respectively, so as to generate two axial forces. The two axial forces generate bending moments opposite to the wind load direction respectively to counteract the wind load, and finally the load on the top of the wind turbine tower is reduced.

[0035] Specifically, before the on-site hoisting of the wind turbine blade, a plurality of sensor strain gauges need to be arranged at the corresponding positions of the blade tip, middle and root in the laboratory in advance. By calibrating the plurality of sensor strain gauges, the relationship between the deformation of the sensor strain gauges and the external load of the blade is obtained. As Figure 7 shown, when the blade bears a load, the strain directions of the sensor strain gauges (shown by the arrows in the figure) are different. The laws of different loads and the deformation of the sensor strain gauges can be calibrated through several load tests.

[0036] The present invention adopts a direct load reduction method, and the designed value of the load reduction capacity is consistent with the actual load reduction capacity, and the performance is reliable. Moreover, by adopting the load reduction method of the present invention, the load on the tower can be reduced by about 1% - 20%, and the weight of the tower can be reduced by about 1% - 10%, which greatly improves the competitiveness of the wind turbine.

[0037] The above is only a preferred embodiment of the present invention for a patent, but the protection scope of the present invention for a patent is not limited thereto. Any person skilled in the art within the scope disclosed by the present invention for a patent, according to the technical solution of the present invention for a patent and its inventive concept, makes equivalent substitutions or changes, all belong to the protection scope of the present invention for a patent.

Claims

1. A method for reducing the load of a wind turbine, characterized in that, Including: A plurality of sensor strain gauges are respectively arranged at the tip, middle, and root positions of the wind turbine blade. Two hydraulically actuated cylinders connected in series are arranged inside the generator of the wind turbine. One of the hydraulically actuated cylinders is fixed to the side wall of the gearbox housing inside the generator, and the piston rod of the other hydraulically actuated cylinder abuts against the inner wall of the generator housing. A plurality of sensor strain gauges are used to measure the deformation of the blade tip, middle, and root in real time, and then the magnitude and direction of the real-time wind load on the wind turbine blade are calculated according to the measured deformation. According to the magnitude and direction of the real-time wind load on the wind turbine blade, two hydraulically actuated cylinders are controlled to apply thrust and reaction forces in the opposite directions to the generator housing and the gearbox housing respectively, thereby generating two axial forces. The bending moments opposite to the wind load direction generated by the two axial forces are used to offset the wind load, and finally the reduction of the tower top load of the wind turbine tower is achieved.

2. The method for reducing the load of a wind turbine according to claim 1, characterized in that: Before the on-site hoisting of the wind turbine blade, a plurality of sensor strain gauges are respectively arranged at the corresponding positions of the blade tip, middle, and root. By calibrating the plurality of sensor strain gauges, the relationship between the deformation of the sensor strain gauges and the external load of the blade is obtained.

3. The method for reducing the load of a wind turbine according to claim 1, characterized in that: The two hydraulically actuated cylinders are respectively a first hydraulically actuated cylinder and a second hydraulically actuated cylinder. The rodless chambers of the first hydraulically actuated cylinder and the second hydraulically actuated cylinder are vertically connected. The first hydraulically actuated cylinder is fixed to the side wall of the gearbox housing, and the piston rod of the second hydraulically actuated cylinder vertically abuts against the inner wall of the generator housing.

4. A system for reducing the load of a wind turbine, characterized in that, Applied to the wind turbine load reduction method according to any one of claims 1 to 3, including a sensor module, a data processing module, a load reduction module, and a control module. The sensor module includes a plurality of sensor strain gauges, which are respectively arranged at the tip, middle, and root positions of the wind turbine blade for measuring the deformation of the blade tip, middle, and root in real time. The data processing module is communicatively connected to the sensor module for calculating the magnitude and direction of the real-time wind load on the wind turbine blade according to the measured deformation in real time. The load reduction module includes two hydraulically actuated cylinders connected in series, which are arranged inside the generator of the wind turbine. One of the hydraulically actuated cylinders is fixed to the side wall of the gearbox housing inside the generator, and the piston rod of the other hydraulically actuated cylinder abuts against the inner wall of the generator housing. The control module is communicatively connected to the data processing module for controlling the two hydraulically actuated cylinders to apply thrust and reaction forces in the opposite directions to the generator housing and the gearbox housing respectively according to the magnitude and direction of the real-time wind load on the wind turbine blade, thereby generating two axial forces. The bending moments opposite to the wind load direction generated by the two axial forces are used to offset the wind load, and finally the reduction of the tower top load of the wind turbine tower is achieved.

5. The system for reducing the load of a wind turbine according to claim 4, characterized in that: The two hydraulically actuated cylinders are respectively a first hydraulically actuated cylinder and a second hydraulically actuated cylinder. The rodless chambers of the first hydraulically actuated cylinder and the second hydraulically actuated cylinder are vertically connected. The first hydraulically actuated cylinder is fixed to the side wall of the gearbox housing, and the piston rod of the second hydraulically actuated cylinder vertically abuts against the inner wall of the generator housing.

6. The system for reducing the load of a wind turbine according to claim 4, characterized in that: Two sensor strain gauges are respectively arranged at each position of the blade tip, middle, and root.

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