A real-time wind turbine tower section load inversion method based on angular displacement

Abstract

The application discloses a kind of real-time wind turbine tower section load inversion methods based on angular displacement, comprising the following steps: by tower top thrust, bending moment load establishes the mathematical model of tower section angular displacement;Based on the mathematical model of step 1, the tower top thrust, bending moment calculation model based on angular displacement is inverted;Real-time angular displacement of two different sections of tower is measured by sensor, and the real-time thrust, bending moment of tower top is obtained by the calculation method of step 2;According to the translation theorem of force, the real-time thrust and bending moment of each tower section are calculated;Based on real-time thrust and bending moment, according to tower design specification, real-time checking is carried out on tower;The comparison result is compared with the preset index;The comparison result is given to wind turbine control system, so as to realize tower load control and reduce unit load.It can control tower operating load in real time, and ensure the normal operation of wind turbine.

Description

Technical Field

[0001] This invention relates to the field of wind power generation tower technology, and in particular to a real-time wind turbine tower section load inversion method based on angular displacement. Background Technology

[0002] With the rapid development of the wind power industry, reducing construction costs and improving power generation efficiency have become the core ways to enhance the economic viability of wind power. In order to reduce the cost per kilowatt-hour of wind power and improve product profitability, domestic and foreign wind power companies are gradually developing larger and lighter blades, and in order to capture better wind resources, they are also required to continuously break through the height barrier of towers.

[0003] Large-capacity wind turbines operate under greater loads. Furthermore, the taller towers also face the challenge of resonance. If the tower load exceeds limits, there is a risk of turbine collapse or even total loss of life. To ensure the normal operation of wind turbines, reduce tower safety hazards, and lower the ultimate load on the turbine, it is necessary to monitor the tower load and implement real-time load reduction control for the tower.

[0004] Currently, strain gauge measurement is the recognized primary method for directly measuring loads. Its main principle is based on the change in resistance caused by mechanical deformation, thus obtaining the stress at the measuring point. It is a microscopic measurement method. However, for towers, the tower load can only be inferred from the stress at the strain gauge measuring point, which is affected by the tower's geometry and the location of the measuring point. Furthermore, this method can only measure bending moment, not thrust. Additionally, strain gauges are constrained by environmental factors and circuit conditions. Therefore, a new method is needed to monitor tower loads. Summary of the Invention

[0005] The purpose of this invention is to provide a real-time wind turbine tower section load inversion method based on angular displacement, which can control the tower operating load in real time and ensure the normal operation of the wind turbine.

[0006] The technical solution adopted in this invention is as follows:

[0007] A method for real-time load inversion calculation of towers based on angular displacement includes the following steps:

[0008] Step 1: Establish a mathematical model of the angular displacement of the tower section using the tower top thrust and bending moment load;

[0009] Step 2: Based on the mathematical model in Step 1, derive the calculation model for tower top thrust and bending moment based on angular displacement;

[0010] Step 3: Measure the real-time angular displacement of two different sections of the tower using sensors, and obtain the real-time thrust and bending moment at the top of the tower using the calculation method in Step 2;

[0011] Step 4: Calculate the real-time thrust and bending moment of each tower section according to the law of translation of forces;

[0012] Step 5: Based on real-time thrust and bending moment, perform real-time verification of the tower according to the tower design specifications;

[0013] Step 6: Compare the verification calculation results with the preset indicators;

[0014] Step 7: The comparison results are fed into the wind turbine generator control system to achieve tower load control and reduce the unit load.

[0015] The primary function of wind turbines during operation is to convert the kinetic energy of moving air, i.e., wind energy, into electrical energy. Wind turbines are subjected to various stresses and loads during operation. Load analysis is crucial for equipment structural design. Wind turbine loads are mainly divided into aerodynamic loads and moment of inertia loads. Aerodynamic loads include steady-state wind and shear wind, while moment of inertia loads include centrifugal force and gravity. The loads experienced by the turbine throughout its entire lifespan are dynamic due to environmental changes and varying operating conditions. Therefore, this solution uses angular displacement for real-time macroscopic measurement of the tower to obtain bending moment and thrust. This method is unaffected by tower geometry, measurement point location, environmental factors, or power line constraints. It allows for early detection and timely handling of load anomalies, avoiding additional costs due to delayed maintenance. This effectively improves the safety performance of wind turbine towers, preventing overloading and ensuring stable wind power generation.

[0016] In step 3, the tower design is mainly constrained by thrust and bending moment. The loads at each interface of the tower can be derived from the translation theorem of forces based on the top load. However, the top load inversion includes two unknowns: the top thrust and bending moment. Therefore, to solve the inversion equations, at least two input data points are required, namely, data from two cross-sections. In step 4, since the towers are currently all custom-designed, each tower section is designed based on the corresponding cross-sectional load. Therefore, to determine whether the tower is safe, it is necessary to calculate the load at each cross-section and verify each tower section.

[0017] Furthermore, in step 1, based on the tower top thrust, bending moment, and tower geometry parameters, and according to the force equilibrium theorem and the cantilever beam displacement calculation formula, the angular displacement of the first section of the tower is:

[0018]

[0019] Where θ1 is the angular displacement of the first section of the tower, l1 is the height of the first tower section, and l m Let m be the height of the m-th tower section, I1 be the moment of inertia of the first tower section, E1 be the elastic modulus of the first tower section, k be the total number of tower sections, and F be the thrust at the top of the tower.

[0020] Similarly, the angular displacement of the second section of the tower is:

[0021]

[0022] Where θ1 is the angular displacement of the first section of the tower, θ2 is the angular displacement of the second section of the tower, and l2 is the height of the second tower section. m Let m be the height of the m-th tower section, I2 be the moment of inertia of the second tower section, E2 be the elastic modulus of the second tower section, k be the total number of tower sections, and F be the thrust at the top of the tower.

[0023] Furthermore, by using analogy and deduction, the formula for calculating the angular displacement of any cross section can be obtained:

[0024] θ i =A i F+B i M

[0025] Among them: A i B i Parameters for angular displacement calculation:

[0026]

[0027] Among them, l n Let I be the height of the nth tower section. n Let E be the moment of inertia of the nth tower section. n Let be the elastic modulus of the nth tower section, k be the total number of tower sections, F be the tower top thrust, and M be the tower top bending moment.

[0028] In addition to constant cross-section towers, wind turbines also offer variable cross-section towers with tapered sections. If the nth tower section has a tapered cross-section, the moment of inertia can be expressed as:

[0029]

[0030] Where, d n1 Let d be the top diameter of the nth tower section. n2 Let t be the bottom diameter of the nth tower section. n Let be the thickness of the nth tower section.

[0031] Furthermore, in step 2, if the angular displacements of any two cross sections are known, the thrust and bending moment at the top of the tower can be obtained through the load inversion equations:

[0032]

[0033] Where F is the thrust at the top of the tower, N is the bending moment at the top of the tower, and θ i Let A be the angular displacement of a cross section. i B i Let θ be the parameter for calculating the angular displacement of a cross section.j For the angular displacement of another section, A j B j The parameters for calculating the angular displacement of another cross section.

[0034] Furthermore, in step 3, sensors can be placed at any two cross-sections of the tower to measure the angular displacement of the two cross-sections in real time. To improve measurement accuracy, the sensors are generally placed at the top of the tower and the tower cross-section adjacent to the top.

[0035] Furthermore, based on the above calculation method, by substituting the angular displacement calculation parameters and the measured angular displacement, the tower top loads F and M are calculated.

[0036] Furthermore, by applying the translation theorem of forces, the thrust and bending moment at any cross-section can be obtained:

[0037]

[0038] Among them, F i Let F be the thrust at this cross section, and M be the thrust at the top of the tower. i The bending moment at this section is M, and the bending moment at the top of the tower is l. m This is the height of the next cross section.

[0039] Furthermore, the tower section was checked in real time according to the tower design specifications, and the check (buckling, strength) coefficients λ for each section of the tower were calculated. i .

[0040] Furthermore, for the sake of unit operation safety, a comparison is made with the given verification index λ. The comparison result is then fed into the wind turbine generator control system. If λ... i If the value is less than λ, it indicates that the tower is safe and the unit can operate normally; otherwise, the control system needs to adjust the unit's operation to precisely reduce the tower load.

[0041] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0042] The present invention provides a real-time wind turbine tower section load inversion method based on angular displacement. The real-time load inversion calculation method based on angular displacement calculates the verification (buckling, strength) coefficients of each section of the tower and compares them with the given verification index, thereby achieving higher precision control of the unit, effectively solving the problem of real-time load control of the tower and ensuring the normal operation of the wind turbine. Attached Figure Description

[0043] The present invention will be described by way of example and with reference to the accompanying drawings, wherein:

[0044] Figure 1 This is a flowchart for angular displacement calculation.

[0045] Figure 2 This is a flowchart of a real-time wind turbine tower section load inversion method based on angular displacement.

[0046] Figure 3 This is a schematic diagram of the tower structure and parameters. Detailed Implementation

[0047] The present invention will now be described in detail with reference to the accompanying drawings.

[0048] All features disclosed in this specification, or all steps in all disclosed methods or processes, may be combined in any way, except for mutually exclusive features and / or steps.

[0049] Any feature disclosed in this specification, unless otherwise stated, may be replaced by other equivalent or similar features. That is, unless otherwise stated, each feature is merely one example of a series of equivalent or similar features.

[0050] A real-time wind turbine tower section load inversion method based on angular displacement. Figure 1 , Figure 2 The flowcharts shown are for calculating the tower's angular displacement and for a real-time tower load reduction control method based on angular displacement, and include the following steps:

[0051] Step 1: Establish a mathematical model of the tower section angular displacement using the tower top thrust and bending moment loads; based on the force equilibrium theorem and the cantilever beam displacement calculation formula, the angular displacement of the first section of the tower is:

[0052]

[0053] Where θ1 is the angular displacement of the first section of the tower, l1 is the height of the first tower section, and l m Let m be the height of the m-th tower section, I1 be the moment of inertia of the first tower section, E1 be the elastic modulus of the first tower section, k be the total number of tower sections, and F be the thrust at the top of the tower.

[0054] Similarly, the angular displacement of the second section of the tower is:

[0055]

[0056] Where θ1 is the angular displacement of the first section of the tower, θ2 is the angular displacement of the second section of the tower, and l2 is the height of the second section of the tower. m Let m be the height of the m-th tower section, I2 be the moment of inertia of the second tower section, E2 be the elastic modulus of the second tower section, k be the total number of tower sections, and F be the thrust at the top of the tower.

[0057] Furthermore, by using analogy and deduction, the formula for calculating the angular displacement of any cross section can be obtained:

[0058] θi =A i F+B i M

[0059] Among them: A i B i Parameters for angular displacement calculation:

[0060]

[0061] Among them, such as Figure 3 As shown, where l n Let I be the height of the nth tower section. n Let E be the moment of inertia of the nth tower section. n Let be the elastic modulus of the nth tower section, k be the total number of tower sections, F be the tower top thrust, and M be the tower top bending moment.

[0062] Specifically, in this embodiment, the tower top (section k) and the adjacent tower section (section k-1) are used as references, and the tower's elastic modulus is E = 2.1 × 10⁻⁶. 11 Pa.

[0063]

[0064]

[0065] In addition to constant cross-section towers, wind turbines also offer variable cross-section towers with tapered sections. If the nth tower section has a tapered cross-section, the moment of inertia can be expressed as:

[0066]

[0067] Where, d n1 Let d be the top diameter. n2 Let t be the base diameter. n For thickness.

[0068] Step 2: Based on the mathematical model in Step 1, derive the calculation model for tower top thrust and bending moment based on angular displacement;

[0069] If the angular displacements of any two cross sections are known, the thrust and bending moment at the top of the tower can be obtained through the load inversion equations:

[0070]

[0071] Step 3: Measure the real-time angular displacement of two different sections of the tower using sensors, and obtain the real-time thrust and bending moment at the top of the tower using the calculation method in Step 2;

[0072] Sensors are placed at any two cross-sections of the tower to measure the angular displacement of the two cross-sections in real time. To improve measurement accuracy, the sensors are placed at the top of the tower and the adjacent cross-section. One displacement sensor is placed at the top of the tower (first cross-section k) and the adjacent cross-section (second cross-section k-1). In the above specific embodiment, although the invention does not theoretically restrict the sensor placement, the tower top load is highly sensitive to angular deviations, so it is necessary to maximize the accuracy of the actual measuring instruments.

[0073] Furthermore, based on the above calculation method, by substituting the angular displacement calculation parameters and the measured angular displacement, the tower top loads F and M are calculated.

[0074] In this embodiment, the first and second sensors measured real-time angular displacements of 2.4146° and 2.3931° at two cross-sections of the tower, respectively. The thrust and bending moment at the tower top can be obtained through the load inversion equations.

[0075]

[0076]

[0077] Step 4: Calculate the real-time thrust and bending moment of each tower section according to the law of translation of forces;

[0078] Using the translation theorem of forces, the thrust and bending moment at any cross section can be obtained:

[0079]

[0080] Step 5: Based on real-time thrust and bending moment, perform real-time verification of the tower according to tower design specifications; calculate the verification (buckling, strength) coefficients λ for each section of the tower. i Specifically, the main tower design standards include GL 2010 and IEC 61400-6-2020.

[0081] Step 6: Compare the verification calculation results with the preset indicators;

[0082] Step 7: The comparison results are fed into the wind turbine generator control system to achieve tower load control and reduce the unit load. For unit operational safety considerations, the results are compared with a given verification index λ. If λ... i If the value is less than λ, it indicates that the tower is safe and the unit can operate normally; otherwise, the control system needs to adjust the unit's operation to precisely reduce the tower load.

[0083] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

Claims

1. A real-time wind turbine tower section load inversion method based on angular displacement, characterized in that: Includes the following steps: Step 1: Establish a mathematical model of the tower section angular displacement using the tower top thrust and bending moment loads: Calculation formula for angular displacement of any section: in: , The calculation parameters for the angular displacement of this section are: in, Let n be the height of the nth tower section. Let n be the moment of inertia of the nth tower section. Let n be the elastic modulus of the tower section. The total number of tower cross sections, For the thrust at the top of the tower, For the bending moment at the top of the tower, This is the height of the next section after this section; Step 2: Based on the mathematical model in Step 1, derive the calculation model for the tower top thrust and bending moment based on angular displacement: The calculation formulas for the tower top thrust and bending moment are as follows: in, For the thrust at the top of the tower, For the bending moment at the top of the tower, For the angular displacement of a cross section, , Here are the parameters for calculating the angular displacement of a cross section. For the angular displacement of another section, , Parameters for calculating the angular displacement of another cross section; Step 3: Measure the real-time angular displacement of two different sections of the tower using sensors, and obtain the real-time thrust and bending moment at the top of the tower using the calculation method in Step 2; Step 4: Calculate the real-time thrust and bending moment of each tower section according to the law of translation of forces; Step 5: Based on real-time thrust and bending moment, perform real-time verification of the tower according to the tower design specifications; Step 6: Compare the verification calculation results with the preset indicators; Step 7: The comparison results are fed into the wind turbine generator control system to achieve tower load control and reduce the unit load.

2. The real-time wind turbine tower section load inversion method based on angular displacement as described in claim 1, characterized in that: When the When the tower section has a tapered cross-section, the moment of inertia is: in, Let n be the top diameter of the nth tower section. Let n be the bottom diameter of the nth tower section. Let be the thickness of the nth tower section.

3. The real-time wind turbine tower section load inversion method based on angular displacement as described in claim 1, characterized in that: In step 3, sensors are placed at any two cross-sections of the tower to measure the angular displacement of the two cross-sections in real time.

4. The real-time wind turbine tower section load inversion method based on angular displacement as described in claim 3, characterized in that: The sensors are positioned at the top of the tower and the adjacent tower section.

5. The real-time wind turbine tower section load inversion method based on angular displacement as described in claim 1, characterized in that: In step 4, the formulas for calculating the thrust and bending moment at any cross-section are as follows: in, Let F be the thrust at that cross section, and F be the thrust at the top of the tower. M is the bending moment at this section, and M is the bending moment at the top of the tower. The height of the next section after this section. This represents the total number of tower cross-sections.

6. The real-time wind turbine tower section load inversion method based on angular displacement as described in claim 1, characterized in that: In step 5, the tower is checked in real time according to the tower design specifications, and the check coefficients for each section of the tower are calculated. .

7. The real-time wind turbine tower section load inversion method based on angular displacement as described in claim 6, characterized in that: The verification coefficients include the buckling coefficient and the strength coefficient.

8. The real-time wind turbine tower section load inversion method based on angular displacement as described in claim 6, characterized in that: In step 7, the comparison results are given to the wind turbine generator control system. If This indicates that the tower is safe and the unit can operate normally; Conversely, the control system needs to adjust the unit's operation to precisely reduce the tower load.

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