Optimization design method for front frame of wind turbine

Abstract

The present invention discloses a method for optimizing the design of a front frame of a wind turbine generator set, and specifically relates to the technical field of design of a front frame of a wind turbine generator set. The method comprises: dividing the front frame into three parts, namely a load-bearing section, a fixed section and a connecting section, according to the position of the load, respectively changing the elastic modulus of the load-bearing section, the fixed section and the connecting section to perform a static stiffness analysis of the load component of the front frame, and optimizing the load-bearing section, the fixed section and the connecting section according to the results of the static stiffness analysis. In this solution, the front frame is divided into three parts, namely a load-bearing section, a fixed section and a connecting section, and the static stiffness analysis of the load component of the front frame is performed by respectively changing the elastic modulus of each section, and the front frame is optimized according to the analysis results. The matching degree between the various parts is higher, and the distribution of materials and structures is more reasonable. Under the premise of ensuring the strength of the front frame, the weight of the front frame can be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of wind turbine front frame design, and in particular to a wind turbine front frame optimization design method. Background Art

[0002] The front frame is a vital component in a wind turbine. There are many other components connected to the front frame. For a direct-drive wind turbine, the front part is connected to the weight of the generator and the load of the hub blades through the main bearing, and the rear part is connected to the weight of the generator and other components through the rear frame. The bottom is indirectly fixed to the tower through the yaw bearing, and a yaw motor is installed on the side.

[0003] The stability of the front frame structure is related to the stable operation of the entire generator set, so the front frame must have sufficient strength. At present, the domestic design technology for the front frame of wind turbines is still immature, the process is not comprehensive, the safety margin of the front frame is usually large, and there are many unreasonable aspects in the structure and material distribution. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for optimizing the design of the front frame of a wind turbine in order to overcome the defects in the prior art that the safety margin of the front frame is usually large and there are many unreasonable aspects in the structure and material distribution.

[0005] The present invention solves the above technical problems through the following technical solutions:

[0006] A wind turbine front frame optimization design method, comprising:

[0007] According to the load action position, the front frame is divided into three parts: the load-bearing section, the fixed section and the connecting section;

[0008] Performing static stiffness analysis of load components on the front frame by respectively changing the elastic moduli of the loaded section, the fixed section, and the connecting section;

[0009] The load-bearing section, the fixed section, and the connecting section are optimized and designed respectively according to the static stiffness analysis results.

[0010] Existing front frame design methods do not consider whether the stiffness matching between various sections of components often results in a certain section having high stiffness and using a lot of materials, but not bearing the corresponding force, resulting in material waste and increased weight. In this solution, the front frame is divided into three parts: a load-bearing section, a fixed section, and a connecting section according to the load application position. The static stiffness analysis of the load components of the front frame is performed by changing the elastic modulus of each section respectively, and the optimization is performed based on the analysis results. This results in a higher matching degree between the various parts and a more reasonable distribution of materials and structures. Under the premise of ensuring the strength of the front frame, the weight of the front frame can be reduced.

[0011] Preferably, performing static stiffness analysis of load components on the front frame by respectively changing the elastic modulus of the loaded section, the fixed section, and the connecting section includes:

[0012] Apply a load component to the hub center of the wind turbine;

[0013] The elastic moduli of the load-bearing section, the fixed section, and the connecting section are changed respectively, and the rate of change of the overall static stiffness of the front frame is calculated.

[0014] In this solution, the load component is applied to the hub center, which is consistent with the actual load distribution of the wind turbine.

[0015] Preferably, before the step of respectively changing the elastic moduli of the loaded section, the fixed section and the connecting section and calculating the rate of change of the overall static stiffness of the front frame, the step further includes:

[0016] calculating deformation amounts of a plurality of test points of the loaded section after applying the load components;

[0017] The test point with the largest deformation among the test points is determined as a reference point, and the overall static stiffness of the front frame is calculated according to the deformation of the reference point.

[0018] In this scheme, taking the point with the maximum deformation as the reference point, the rate of change of the overall static stiffness of the front frame is more obvious.

[0019] Preferably, the optimizing design of the load-bearing section, the fixed section, and the connecting section respectively according to the static stiffness analysis result includes:

[0020] Set the stiffness matching range based on lightweight goals and front frame structure;

[0021] respectively calculating the change rates of the overall static stiffness of the loaded section, the fixed section, and the connecting section after the elastic modulus is changed;

[0022] If the absolute value of the change rate is within the stiffness matching range, no optimization is required;

[0023] If the absolute value of the change rate is less than the stiffness matching range, reducing the stiffness of the corresponding loaded section, the fixed section, or the connecting section;

[0024] If the absolute value of the change rate exceeds the stiffness matching range, the stiffness of the corresponding loaded section, the fixed section, or the connecting section is increased.

[0025] In this solution, the stiffness matching range is set according to the lightweight goal and the front frame structure to suit the actual situation. By comparing the change rate of the overall static stiffness of the front frame with the stiffness matching range, targeted adjustments can be made to each section.

[0026] Preferably, the optimizing design of the load-bearing section, the fixed section, and the connecting section according to the static stiffness analysis results further includes:

[0027] After the design is optimized, the strength and fatigue life of the front frame are checked;

[0028] If the strength check or fatigue life check fails, the optimization design shall be re-performed;

[0029] If the strength check and fatigue life check are passed, the optimized design is completed.

[0030] In this solution, it is ensured that the front frame after optimized design can meet the strength verification and fatigue life verification.

[0031] Preferably, if the absolute value of the change rate is less than the stiffness matching range, reducing the stiffness of the corresponding loaded section, the fixed section, or the connecting section includes:

[0032] The optimized location is determined based on the direction of the load component.

[0033] In this solution, the optimized position is more precise.

[0034] Preferably, determining the optimized position according to the direction of the load component includes:

[0035] Material is reduced in the direction of the load component where the absolute value of the change rate is smaller than the stiffness matching range.

[0036] Preferably, if the absolute value of the change rate exceeds the stiffness matching range, increasing the stiffness of the corresponding loaded section, the fixed section, or the connecting section includes:

[0037] The optimized location is determined based on the direction of the load component.

[0038] In this solution, the optimized position is more precise.

[0039] Preferably, determining the optimized position according to the direction of the load component includes:

[0040] Material is added in the direction of the load component where the absolute value of the change rate exceeds the stiffness matching range.

[0041] Preferably, the load-bearing section is the front flange of the front frame, the fixing section is the bottom of the front frame, and the connecting section is the middle portion between the load-bearing section and the fixing section of the front frame.

[0042] The positive progress of the present invention is that the existing front frame design method does not consider whether the stiffness matching between the various sections of the components is achieved, which often results in a certain section having a large stiffness and using a lot of material, but not being able to withstand the corresponding force, resulting in material waste and increased weight. In this solution, the front frame is divided into three parts: a load-bearing section, a fixed section, and a connecting section. The static stiffness analysis of the load components of the front frame is performed by changing the elastic modulus of each section respectively, and the front frame is optimized based on the analysis results. This results in a higher matching degree between the various sections and a more reasonable distribution of materials and structures. Under the premise of ensuring the strength of the front frame, the weight of the front frame can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a structural diagram of a front frame of a wind turbine generator set according to a preferred embodiment of the present invention;

[0044] Figure 2 A schematic diagram of load components of a front frame optimization design method according to a preferred embodiment of the present invention;

[0045] Figure 3 This is a flow chart of a method for optimizing the design of a front frame of a wind turbine generator set according to a preferred embodiment of the present invention;

[0046] Figure 4 This is a flow chart of optimizing the design of the load-bearing section, the fixed section, and the connecting section respectively according to the static stiffness analysis results of a preferred embodiment of the present invention;

[0047] Figure 5 This is a data graph showing the effect of changing the elastic modulus of the loaded section, fixed section, and connecting section on the overall static stiffness change rate of the front frame.

[0048] Loading section 100

[0049] Connecting section 200

[0050] Fixed section 300

[0051] Hub Center 400 DETAILED DESCRIPTION

[0052] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples.

[0053] like Figures 1-4 As shown, in this embodiment, a method for optimizing the front frame of a wind turbine generator system includes:

[0054] Step 10: Divide the front frame into three parts according to the load acting position: the load-bearing section 100, the fixed section 300 and the connecting section 200.

[0055] Specifically, if Figure 1As shown, the load-bearing section 100 is the front flange of the front frame. It supports the weight of the generator and the load of the hub blades via the main shaft. The fixed section 300 is the bottom of the front frame. The rear of the fixed section 300 supports the weight of the generator via the rear frame. The fixed section 300 is mounted on the yaw motor. The connecting section 200 is the middle portion between the load-bearing section 100 and the fixed section 300. In other words, the load-bearing section 100 supports the weight of the generator and the load of the hub blades via the main shaft. The fixed section 300 is mounted on the yaw motor and supports the weight of the generator via the rear frame. The connecting section 200 is located between the load-bearing section 100 and the fixed section 300, and the load-bearing section 100 and the fixed section 300 are connected by the connecting section 200.

[0056] Step 20: Perform static stiffness analysis of the load components of the front frame by changing the elastic moduli of the loaded section 100, the fixed section 300, and the connecting section 200 respectively.

[0057] Among them, the finite element analysis technology is used for analysis. When the elastic modulus of one section is changed, the elastic moduli of the other two sections do not change.

[0058] Step 30: Optimize the design of the loaded section 100, the fixed section 300, and the connecting section 200 according to the results of the static stiffness analysis. The optimization design is to adjust the stiffness of the loaded section 100, the fixed section 300, and the connecting section 200, respectively, that is, reduce or increase the stiffness of the loaded section 100, the fixed section 300, and the connecting section 200 according to the results of the static stiffness analysis.

[0059] Existing front frame design methods do not consider whether the stiffness matching between various sections of the components often results in a certain section having high stiffness and using a lot of material, but not bearing the corresponding force, resulting in material waste and increased weight. In this solution, the front frame is divided into three parts according to the load application position: a load-bearing section 100, a fixed section 300, and a connecting section 200. By changing the elastic modulus of each section, the static stiffness of the load component of the front frame is analyzed, and optimization is performed based on the analysis results. This improves the matching degree between the various sections and makes the distribution of materials and structures more reasonable. Under the premise of ensuring the strength of the front frame, the weight of the front frame can be reduced.

[0060] In this embodiment, the static stiffness analysis of the load components of the front frame is performed by changing the elastic modulus of the loaded section 100, the fixed section 300, and the connecting section 200 respectively, including:

[0061] A load component is applied to the hub center 400 of the wind turbine.

[0062] Among them, such as Figure 2As shown, the load components are six components Mx, My, Mz, with a magnitude of 10000 kNm and Fx, Fy, Fz, with a magnitude of 1000 kN, applied at 400 points in the center of the hub respectively. The hub (not shown in the figure) is connected to the loaded section 100.

[0063] The elastic moduli of the load-bearing section 100 , the fixed section 300 , and the connecting section 200 are changed respectively, and the change rate of the overall static stiffness of the front frame is calculated.

[0064] In this solution, a load component is applied to the hub center 400, which is consistent with the actual load distribution of the wind turbine.

[0065] In this embodiment, before the step of respectively changing the elastic modulus of the loaded section 100, the fixed section 300, and the connecting section 200 and calculating the rate of change of the overall static stiffness of the front frame, the following steps are further included:

[0066] Calculating the deformation of several test points of the loaded section 100 after applying the load components;

[0067] Among them, the deformation under six components is calculated separately.

[0068] The test point with the largest deformation among the test points is determined as a reference point, and the overall static stiffness of the front frame is calculated according to the deformation of the reference point.

[0069] In this scheme, taking the point with the maximum deformation as the reference point, the rate of change of the overall static stiffness of the front frame is more obvious.

[0070] like Figure 4 As shown, in this embodiment, the optimization design of the loaded section 100, the fixed section 300, and the connecting section 200 is performed based on the static stiffness analysis results, including:

[0071] Step 31: Set a stiffness matching range based on the lightweight target and the front frame structure.

[0072] Step 32: Calculate the change rate of the overall static stiffness of the loaded section 100, the fixed section 300, and the connecting section 200 after the elastic modulus is changed.

[0073] Step 34: If the absolute value of the change rate is within the stiffness matching range, no optimization is required.

[0074] Step 33: If the absolute value of the change rate is smaller than the stiffness matching range, the stiffness of the corresponding loaded section 100 , fixed section 300 , or connecting section 200 is reduced.

[0075] Step 35: If the absolute value of the change rate exceeds the stiffness matching range, the stiffness of the corresponding loaded section 100, fixed section 300, or connecting section 200 is increased.

[0076] In this solution, the stiffness matching range is set according to the lightweight goal and the front frame structure to suit the actual situation. By comparing the change rate of the overall static stiffness of the front frame with the stiffness matching range, targeted adjustments can be made to each section.

[0077] Preferably, if the absolute value of the change rate exceeds the stiffness matching range, increasing the stiffness of the corresponding loaded section 100 or fixed section 300 or connecting section 200 includes:

[0078] The optimized location is determined based on the direction of the load component.

[0079] In this solution, the optimized position is more precise.

[0080] Determining the optimized location based on the direction of the load component includes:

[0081] Add material in the direction of the load component where the absolute value of the rate of change exceeds the stiffness matching range.

[0082] In this embodiment, if the absolute value of the change rate is less than the stiffness matching range, reducing the stiffness of the corresponding loaded section 100, fixed section 300, or connecting section 200 includes:

[0083] The optimized location is determined based on the direction of the load component.

[0084] In this solution, the optimized position is more precise.

[0085] In this embodiment, determining the optimized location according to the direction of the load component includes:

[0086] Material is reduced in the direction of the load component where the absolute value of the rate of change is less than the stiffness matching range.

[0087] In this embodiment, the data of the rate of change of the overall static stiffness of the front frame is as follows: Figure 5 shown.

[0088] Specifically, the stiffness matching range is set to 5%-15% based on the lightweight target and the front frame structure, such as Figure 5 As shown, the absolute values ​​of the change rates exceed the stiffness matching range in the Mz and Fy directions of the loaded segment 100 and in the Mx and My, Fx and Fz directions of the connecting segment 200.

[0089] For the Mz direction of the loaded section 100, the moment of inertia of the bending section about the Z axis is Iz = ht 3 / 12, where h is the height of the loaded section 100 and t is the thickness of the loaded section 100. To improve the bending stiffness under Mz, the thickness of the front flange should be increased. The Fy load and Mz load on the loaded section 100 have the same effect, so the optimization design for the Fy direction is the same as that for the Mz direction.

[0090] Because the My and Mz loads are similar in magnitude, that is, the bending moments of the connecting section 200 in all directions of the circumference are also similar, a circular cross section is selected when designing the connecting section 200. For the Mx direction of the connecting section 200, the moment of inertia of the torsional section Ip=π(D 4 -d 4 ) / 32, where D is the outer diameter of the connecting section 200 ring, and d is the inner diameter of the connecting section 200 ring. To improve the torsional rigidity of the connecting section 200, D should be appropriately increased. To avoid additional bending moment, the intersection of the connecting section 200 and the fixed section 300 should be near the yaw slider screw fixing point.

[0091] Regarding the My direction of connecting segment 200, referring to the formulas for the moment of inertia of the bending section about the y-axis and parallel displacement, it can be seen that Iy is approximately proportional to the square of the upper cross-sectional area. Therefore, to improve the bending stiffness of connecting segment 200 under the action of My, the size of the opening in the upper portion of connecting segment 200 should be reduced, and the upper cross-sectional area should be increased. The Fx and Fz loads on connecting segment 200 have the same effect as the My load, so the optimization design for the Fx and Fz directions is the same as for the Mz direction.

[0092] By changing the elastic modulus of the fixed section 300, except for the load component in the Mz direction, the absolute value of the change rate of the overall static stiffness under the other load components is smaller than the stiffness matching range. Therefore, the thickness of the fixed section 300 can be appropriately reduced during design, thereby reducing the stiffness.

[0093] In this embodiment, optimizing the design of the loaded section 100, the fixed section 300, and the connecting section 200 based on the static stiffness analysis results further includes:

[0094] After optimizing the design, the strength and fatigue life of the front frame are checked;

[0095] If the strength check or fatigue life check fails, the optimization design shall be re-performed;

[0096] If the strength check and fatigue life check are passed, the optimized design is completed.

[0097] In this solution, it is ensured that the front frame after optimized design can meet the strength verification and fatigue life verification.

[0098] This embodiment optimizes the design of the front frame of a one-megawatt wind turbine, reducing its weight from 47.3 tons to 37.3 tons, a weight reduction of 10 tons, and a weight reduction rate of up to 21.1%.

[0099] Although specific embodiments of the present invention have been described above, those skilled in the art will appreciate that these are merely illustrative and that the scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, and such changes and modifications are intended to fall within the scope of the present invention.

Claims

1. A wind turbine front frame optimization design method, characterized in that: include: According to the load action position, the front frame is divided into three parts: the load-bearing section, the fixed section and the connecting section; Performing static stiffness analysis of load components on the front frame by respectively changing the elastic moduli of the loaded section, the fixed section, and the connecting section; According to the static stiffness analysis results, the load-bearing section, the fixed section, and the connecting section are optimized and designed respectively, specifically including: Set the stiffness matching range based on lightweight goals and front frame structure; respectively calculating the change rates of the overall static stiffness of the loaded section, the fixed section, and the connecting section after the elastic modulus is changed; The absolute values ​​of the change rates are compared within the stiffness matching range, and the stiffness of the loaded section, the fixed section, or the connecting section is adjusted according to the comparison result.

2. The wind turbine front frame optimization design method according to claim 1, characterized in that: Performing static stiffness analysis of load components on the front frame by respectively changing the elastic modulus of the loaded section, the fixed section, and the connecting section includes: Apply a load component to the hub center of the wind turbine; The elastic moduli of the load-bearing section, the fixed section, and the connecting section are changed respectively, and the rate of change of the overall static stiffness of the front frame is calculated.

3. The wind turbine front frame optimization design method according to claim 2, characterized in that: Before the step of respectively changing the elastic moduli of the loaded section, the fixed section, and the connecting section and calculating the rate of change of the overall static stiffness of the front frame, the step further includes: calculating deformation amounts of a plurality of test points of the loaded section after applying the load components; The test point with the largest deformation among the test points is determined as a reference point, and the overall static stiffness of the front frame is calculated according to the deformation of the reference point.

4. The wind turbine front frame optimization design method according to claim 1, characterized in that: The adjusting the stiffness of the loaded section, the fixed section, or the connecting section according to the comparison result specifically includes: If the absolute value of the change rate is within the stiffness matching range, no optimization is required; If the absolute value of the change rate is less than the stiffness matching range, reducing the stiffness of the corresponding loaded section, the fixed section, or the connecting section; If the absolute value of the change rate exceeds the stiffness matching range, the stiffness of the corresponding loaded section, the fixed section, or the connecting section is increased.

5. The wind turbine front frame optimization design method according to claim 4, characterized in that: If the absolute value of the change rate is less than the stiffness matching range, reducing the stiffness of the corresponding loaded section, the fixed section, or the connecting section includes: The optimized location is determined based on the direction of the load component.

6. The wind turbine front frame optimization design method according to claim 5, characterized in that: Determining the optimized position according to the direction of the load component includes: Material is reduced in the direction of the load component where the absolute value of the change rate is smaller than the stiffness matching range.

7. The wind turbine front frame optimization design method according to claim 4, characterized in that: If the absolute value of the change rate exceeds the stiffness matching range, increasing the stiffness of the corresponding loaded section, the fixed section, or the connecting section includes: The optimized location is determined based on the direction of the load component.

8. The wind turbine front frame optimization design method according to claim 7, characterized in that: Determining the optimized position according to the direction of the load component includes: Material is added in the direction of the load component where the absolute value of the change rate exceeds the stiffness matching range.

9. The wind turbine front frame optimization design method according to claim 1, characterized in that: The optimizing design of the load-bearing section, the fixed section, and the connecting section according to the static stiffness analysis results further includes: After the design is optimized, the strength and fatigue life of the front frame are checked; If the strength check or fatigue life check fails, the optimization design shall be re-performed; If both the strength check and fatigue life check pass, the optimized design is completed.

10. The wind turbine front frame optimization design method according to claim 1, characterized in that: The load-bearing section is the front flange of the front frame, the fixing section is the bottom of the front frame, and the connecting section is the middle portion between the load-bearing section and the fixing section of the front frame.

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