A bidirectional cable net flexible photovoltaic support system and a bidirectional pre-tension collaborative optimization method

Abstract

The application discloses a bidirectional cable net flexible photovoltaic support system and a bidirectional pre-tension force collaborative optimization method, and relates to the technical field of photovoltaic power generation. The support system comprises a plurality of orthogonally arranged main bearing cables and secondary bearing cables, each set of tetrahedral connection domain is connected with the main bearing cable and the secondary bearing cable through a four-vertex clamping structure, a rigid space orthogonal bidirectional cable net is formed, and a photovoltaic module is fixed to the secondary bearing cable and forms an installation inclination angle through a cable end vertical height difference. The optimization method firstly determines a structural target working state, establishes a parameterized numerical model to construct a fast mapping relationship between the pre-tension force and the working state, combines four types of constraints to construct a bidirectional pre-tension force collaborative safety domain, and finally inversely solves an optimal pre-tension force combination. The application improves the bidirectional cable net collaborative stress performance and torsional stiffness through the tetrahedral rigid node, realizes accurate pre-tension force configuration in combination with the collaborative optimization method, and effectively improves the structural stability of the large-span flexible support and the component posture control precision.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic power generation technology, and in particular to a bidirectional cable-net flexible photovoltaic support system and a bidirectional pretension synergistic optimization method. Background Technology

[0002] In photovoltaic new energy projects, flexible photovoltaic supports are effectively applied in special scenarios such as mines and valleys due to their large span, low foundation requirements, and strong adaptability to complex terrain. The bidirectional cable-net flexible photovoltaic support system forms a spatially coordinated force-bearing structure through a bidirectional load-bearing cable system. Compared with traditional unidirectional cable-net supports, it not only improves overall stiffness and load distribution capacity but also enhances structural robustness, making it the preferred support system for large-span and complex terrain photovoltaic projects.

[0003] However, the longitudinal and transverse load-bearing cables of the bidirectional cable-net flexible photovoltaic support system are coupled, and their pretension level directly affects the initial attitude of the cable net, the structural forming state, and the internal force distribution and deflection response under conditions such as wind and snow. If the bidirectional pretension configuration is unreasonable, it can easily lead to uneven cable force distribution, excessive local deformation, and structural attitude deviation, affecting the safety of the support system and the operating performance of the photovoltaic modules. At the same time, most of the existing bidirectional cable net intersections adopt a hinged structure, which has insufficient node stiffness and is prone to torsional misalignment and cable slippage, making it difficult to ensure the coordinated force-bearing efficiency of the bidirectional cable system. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a bidirectional cable-net flexible photovoltaic support system, comprising main load-bearing cables, secondary load-bearing cables, tetrahedral connecting domains, main cable columns, main cable anchors, secondary cable columns, and secondary cable anchors. Multiple main and secondary load-bearing cables are provided. The main load-bearing cables are arranged parallel to each other longitudinally, with both ends supported by main cable columns and anchored to the foundation by main cable anchors. Multiple tetrahedral connecting domains are provided. In each tetrahedral connecting domain, two opposite vertices are fixedly connected to one main load-bearing cable, and the other two opposite vertices are fixedly connected to one secondary load-bearing cable, with the two vertices located on opposite sides of the main load-bearing cable. The tetrahedral connecting domains form a spatially orthogonal bidirectional cable net between the main and secondary load-bearing cables. Photovoltaic modules are fixed to the secondary load-bearing cables in a continuous array. The secondary cable columns support the ends of the secondary load-bearing cables at their transverse ends and are anchored to the foundation by secondary cable anchors, forming an end anchoring structure together with the main cable columns and main cable anchors.

[0005] Furthermore, the main load-bearing cable bears the vertical load transmitted by the secondary load-bearing cable and provides longitudinal torsional stiffness. The secondary load-bearing cable directly bears the self-weight of the photovoltaic module and forms the installation tilt angle of the photovoltaic module through the height difference between the two ends. The main load-bearing cable and the secondary load-bearing cable form a spatially coordinated force-bearing system through rigid coupling of the tetrahedral connection domain.

[0006] Furthermore, the tetrahedral connection domain includes four rigid rods, a connecting sleeve, a connecting cover plate, and connecting bolts. The inner ends of the four rigid rods converge and are fixed to the outer wall of the connecting sleeve, while the outer ends extend to form the four vertices of the spatial tetrahedron. The connecting sleeves at the four vertices are fixedly connected to the connecting cover plate, and the connecting cover plate is fastened to the connecting bolts to clamp the main load-bearing cable and the secondary load-bearing cable.

[0007] Furthermore, the main cable columns and secondary cable columns are made of concrete or steel to bear vertical pressure and horizontal shear force. The main cable anchors and secondary cable anchors are made of cables or tie rods to bear only axial tension. The top elevation of the secondary cable column is adjusted according to the end elevation of the secondary load-bearing cable to adapt to the installation inclination angle.

[0008] On the other hand, the present invention provides a bidirectional preload co-optimization method, comprising the following steps: Determine the target operating state of the bidirectional cable net support system; Establish a numerical model of the two-way cable net support system, and input the geometry, load, materials and constraints; Construct a rapid mapping model between cable prestress and structural working state; Constructing a bidirectional cable-stayed prestressed collaborative safety domain; Within the collaborative safety domain, determine the bidirectional preload combination that meets the target working state requirements.

[0009] Furthermore, there is a coupled and synergistic relationship between the pretension of the main load-bearing cable and the pretension of the secondary load-bearing cable. When the pretension of the main load-bearing cable increases, the overall stiffness of the structure increases, and the required pretension of the secondary load-bearing cable decreases accordingly. When the pretension of the secondary load-bearing cable increases, the lateral constraint effect is enhanced, and the required pretension of the main load-bearing cable decreases accordingly. Based on the synergistic function relationship between the two, the pretension is synergistically configured.

[0010] Furthermore, the structural working state includes one or more of the following: mid-span vertical deflection, structural torsion angle, cable resistance partial factor, and structural dynamic characteristics. A structural response sample set is generated by systematically sampling the bidirectional preload parameter space, and a fast mapping model is constructed based on the sample set to achieve rapid prediction of the structural working state.

[0011] Furthermore, the bidirectional preload collaborative safety domain is jointly defined by the upper limit boundary of cable force under wind pressure conditions, the lower limit boundary of cable force under wind suction conditions, the control boundary of photovoltaic array torsional deformation, and the control boundary of anchorage structure bearing capacity.

[0012] Furthermore, the four types of boundaries are mapped to the parameter space formed by the pretension of the main load-bearing cable and the pretension of the secondary load-bearing cable, forming a closed cooperative safety domain. Pretension combinations located outside the cooperative safety domain are determined to be infeasible solutions.

[0013] Furthermore, the bidirectional preload combination that satisfies the target working state is obtained by using the fast mapping model inversion. This combination is then mapped to the cooperative safety domain for verification. If the combination is within the safety domain, it is determined as the design preload combination. If the combination is outside the safety domain, it is iteratively corrected until both the target working state and the safety domain constraints are satisfied.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention employs an orthogonal bidirectional cable net structure combined with a tetrahedral rigid connection domain. By clamping and fixing the primary and secondary cables at the four vertices of the tetrahedron, the rigid intersection of the primary and secondary cables is achieved. This transforms the traditional hinged nodes into spatial rigid nodes, significantly improving the in-plane and out-of-plane stiffness and torsional performance of the nodes. It avoids cable slippage and torsional misalignment, achieving efficient synergistic force distribution between the primary and secondary cables. Overall, it enhances the vertical stiffness and morphological stability of the support system, making it suitable for applications with large spans and complex terrains.

[0015] 2. This invention directly forms the installation tilt angle of photovoltaic modules by the height difference between the two ends of the secondary load-bearing cable, eliminating the need for additional tilt adjustment components, simplifying the upper node structure, reducing material usage and construction complexity, and allowing for flexible adjustment of the column top elevation to adapt to different terrain elevation differences and tilt angle requirements.

[0016] 3. The bidirectional pretension synergistic optimization method proposed in this invention fully considers the coupling and synergistic effect of the pretension of the primary and secondary cables, constructs a synergistic safety domain under multiple working conditions, and solves the optimal pretension combination by combining the target working state inversion. Compared with the traditional forward design method, it can directly ensure the rationality of the photovoltaic module installation posture and structural stress, avoid the problem of excessive cable force or cable slack caused by single working condition design, and improve the operational safety of the structure under complex wind loads.

[0017] 4. The end anchoring structure of the present invention adopts a force division mode of column bearing pressure and anchor bearing tension, which makes full use of the mechanical properties of materials, reduces redundant components and improves material utilization efficiency while ensuring structural safety. At the same time, it reduces the difficulty of on-site tensioning and debugging, and improves construction efficiency and engineering economy. Attached Figure Description

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments: Figure 1 This is a schematic diagram of the overall structure of the bidirectional cable-net flexible photovoltaic support system of the present invention; Figure 2 This is a side view of the main load-bearing cable of the bidirectional cable net flexible photovoltaic support system of the present invention; Figure 3 This is a side view of the secondary load-bearing cable of the bidirectional cable-net flexible photovoltaic support system of the present invention; Figure 4 This is an isometric view of the connection node between the main and secondary load-bearing cables of the present invention; Figure 5 This is a top view of the connection node between the main and secondary load-bearing cables of the present invention; Figure 6 This is a front view of the connection node between the main and secondary load-bearing cables of the present invention; Figure 7 This is a side view of the connection node between the main and secondary load-bearing cables of the present invention; Figure 8 This is a schematic diagram of the spatial structure of the rods in the tetrahedral connection domain of the present invention; Figure 9 This is a schematic diagram of the cross-sectional structure of the cable-rod connection node of the present invention; Figure 10 This is a side view of the cable and rod connection of the present invention; Figure 11 This is a top view of the cable and rod connection of the present invention; Figure 12 This is a flowchart of the pre-tension inversion process based on the target working state according to the present invention; Figure 13 This is a flowchart of the bidirectional pretension collaborative optimization method of the present invention.

[0019] In the diagram, 1. Main load-bearing cable; 2. Secondary load-bearing cable; 3. Tetrahedral connection area; 4. Main cable column; 5. Main cable anchor; 6. Secondary cable column; 7. Secondary cable anchor; 8. Photovoltaic module; 9. Rigid member; 10. Connecting sleeve; 11. Connecting cover plate; 12. Connecting bolt. Detailed Implementation

[0020] The specific embodiments of the present invention will be further described in detail with reference to the accompanying drawings.

[0021] like Figures 1 to 3 As shown, the bidirectional cable net flexible photovoltaic support system described in this embodiment is an orthogonal bidirectional spatial cable net structure, including multiple parallel main load-bearing cables 1, multiple parallel secondary load-bearing cables 2, several sets of tetrahedral connecting domains 3, and an end anchoring structure composed of main cable columns 4, main cable anchors 5, secondary cable columns 6, and secondary cable anchors 7. The photovoltaic modules 8 are laid and fixed above the secondary load-bearing cables 2. The main load-bearing cables 1 are made of high-strength galvanized steel strands, extending longitudinally in the north-south direction, and are arranged parallel at equal intervals according to a set spacing to form the main body of the longitudinal cable net. The two ends of each main load-bearing cable 1 are supported on the top of the main cable column 4, and are in force balance with the main cable anchor 5. The tension at the cable end is transferred to the ground anchoring foundation through the main cable anchor 5. The main load-bearing cables 1 are the main load-bearing components of the system, bearing all the vertical loads transmitted by the secondary load-bearing cables 2 and the photovoltaic modules 8, while providing longitudinal overall torsional stiffness and controlling the vertical deflection and torsional deformation of the cable net. Figure 2 The side view of the system along the direction of the main load-bearing cable 1 can intuitively show the force relationship between the sag of the main cable and the end anchorage. Figure 3The side view of the system along the direction of the secondary load-bearing cable 2 shows the arrangement of the inclination angle of the secondary cable and the lateral anchorage.

[0022] Multiple sets of tetrahedral connection domains 3 are arranged at intervals along the length of each main load-bearing cable 1. Two opposite vertices of each tetrahedral connection domain 3 are fixedly connected to a longitudinal main load-bearing cable 1, and the other two opposite vertices are fixedly connected to a transverse secondary load-bearing cable 2. The two secondary cable connection vertices are located on opposite sides of the main load-bearing cable 1. The tetrahedral connection domains 3 achieve rigid intersection and spatial orthogonal arrangement of the bidirectional cables at the nodes. The multi-view morphology of the main and secondary load-bearing cable connection nodes is as follows: Figures 4 to 7 As shown, where Figure 4 The isometric drawings of the main and secondary load-bearing cable connection nodes can intuitively present the spatial assembly relationship between the bidirectional cable and the tetrahedral connection domain 3; Figure 5 The top view of the connection nodes of the main and secondary load-bearing cables can clearly show the planar shape and node distribution pattern of the orthogonal arrangement of the bidirectional cables; Figure 6 The front view of the connection node between the main and secondary load-bearing cables can show the vertical structure of the node and the vertical positional relationship between the cable body; Figure 7 The side view of the connection node between the primary and secondary load-bearing cables can show the logic behind the vertical height difference and inclination angle between the secondary load-bearing cable 2 and the primary load-bearing cable 1.

[0023] The secondary load-bearing cable 2 also uses high-strength galvanized steel strand, extending laterally in an east-west direction, passing through the tetrahedral connecting regions 3 at the corresponding positions of each main load-bearing cable 1, and together with multiple longitudinal main load-bearing cables 1, forming a continuous orthogonal bidirectional cable net. The photovoltaic modules 8 are directly fixed to the upper edge of the secondary load-bearing cable 2 by aluminum alloy clamp fasteners, and are continuously laid along the direction of the secondary cable to form a complete photovoltaic array. By setting the vertical height difference between the corresponding tetrahedral connecting regions 3 at both ends of the same secondary load-bearing cable 2, the secondary load-bearing cable 2 can form a set tilt angle in the lateral direction, thereby ensuring that the photovoltaic modules 8 achieve the designed installation tilt angle, eliminating the need for additional tilt angle supports and simplifying the upper structure. The secondary load-bearing cable 2 directly bears the self-weight, snow load, and local wind pressure and wind suction load of the photovoltaic module 8. At the same time, it forms a lateral constraint on the main load-bearing cable 1 through lateral tension, limiting the out-of-plane swing and torsional deformation of the main cable. The main load-bearing cable 1 provides vertical support for the secondary load-bearing cable 2. The two are rigidly coupled through the tetrahedral connection domain 3 to form a spatially coordinated force-bearing system, which significantly improves the overall stiffness and anti-instability capability compared with the unidirectional cable system.

[0024] The tetrahedral connection domain 3 serves as a transfer hub for bidirectional cable forces, uniformly transferring the vertical and horizontal loads of the secondary load-bearing cable 2 to the main load-bearing cable 1. Simultaneously, it constrains the relative rotation and slippage of the bidirectional cables at the nodes, avoiding problems such as torsional misalignment and cable slippage that are prone to occur at hinged nodes, thus ensuring the stability of the cable net node geometry. For example... Figures 8 to 11As shown, the tetrahedral connection domain 3 consists of four rigid rods 9, a connecting sleeve 10, a connecting cover plate 11, and connecting bolts 12, forming a spatial tetrahedral rigid node. Figure 8 This is a schematic diagram of the spatial structure of the rods in the tetrahedral connection domain. The rigid rods 9 are made of Q355 seamless steel pipes. The inner ends of the four rigid rods 9 meet at a set spatial angle and are welded and fixed to the outer wall of the central connecting sleeve 10. The outer ends of the four rods extend outward to form the four vertices of the spatial tetrahedron.

[0025] Figure 9 This is a schematic diagram of the cross-sectional structure of the cable and rod connection node. Connecting sleeves 10 and connecting cover plates 11 are provided at each of the four vertices. The connecting sleeves 10 and connecting cover plates 11 are fixedly fitted together and fastened by 8.8 grade high-strength connecting bolts 12. The main load-bearing cable 1 and the secondary load-bearing cable 2 are respectively inserted to achieve a reliable rigid connection between the cable body and the tetrahedral node. Figure 10 This is a side view of the cable and rod connection. Figure 11 This is a top view of the cable-rod connection, which can show the clamping and assembly relationship between the cable and the node, the bolt arrangement, and the spatial angle of the rod from different dimensions. This structure can achieve balanced transmission of multi-directional forces at the node through the axial force transmission of the rigid rod 9, while also possessing excellent torsional and bending stiffness, effectively constraining the spatial deformation of the node.

[0026] The end anchoring structures are set at both the longitudinal and transverse ends of the bidirectional cable net. The main cable column 4 and the secondary cable column 6 can be made of steel pipe concrete columns or H-shaped steel columns, with the column base fixed to the top surface of the foundation, mainly bearing vertical pressure and horizontal shear force. The main cable anchor 5 and the secondary cable anchor 7 can be made of high-strength steel tie rods or prestressed cables, with the upper end connected to the anchoring end of the column and the lower end obliquely anchored to the ground foundation, bearing only axial tension. The division of force between column pressure bearing and anchor tension bearing can give full play to the mechanical properties of materials. The column top elevation of the secondary cable column 6 can be flexibly adjusted according to the end elevation of the secondary load-bearing cable 2, adapting to different component inclination angles and terrain elevation differences, realizing the overall anchoring and spatial shape fixation of the bidirectional cable net.

[0027] like Figure 12 , Figure 13 As shown, the bidirectional pretension synergistic optimization method described in this embodiment is implemented based on the aforementioned bidirectional cable-net flexible photovoltaic support system. Its core lies in driving the pretension design with structural target performance, fully revealing the synergistic coupling mechanism between the main load-bearing cable 1 and the secondary load-bearing cable 2. Among these... Figure 13 This is a flowchart of the bidirectional preload co-optimization method, covering the entire process from parameter modeling to result output; Figure 12This is a flowchart illustrating the pretension inversion process based on the target working state, presenting the closed-loop logic of inversion verification and iterative correction. Its working principle lies in the fact that the pretension Tm of the main load-bearing cable 1 and the pretension Ts of the secondary load-bearing cable 2 are not independent variables; they exhibit a significant coupling substitution effect: when the pretension Tm of the main load-bearing cable 1 increases, the overall vertical stiffness and torsional stiffness of the bidirectional cable net system significantly improve, while the structural deflection and torsional deformation decrease markedly, thus reducing the pretension Ts of the secondary load-bearing cable 2 required to maintain the target working state. Conversely, when the pretension Ts of the secondary load-bearing cable 2 increases, the constraint effect of the transverse cable net on the longitudinal cable net strengthens, improving the structural transverse stability and overall torsional performance, thus correspondingly reducing the pretension Tm of the main load-bearing cable 1 required to maintain the same target working state. Simultaneously, wind pressure conditions increase the internal forces within the cables, determining the upper limit of the allowable pretension; wind suction conditions offset part of the pretension, determining the lower limit of the allowable pretension. Combined with torsional control and anchorage bearing constraints, these factors collectively enclose a feasible range of pretension parameters.

[0028] In specific implementation, firstly according to Figure 13 The overall process clarifies the target working state parameters of the bidirectional cable-net flexible photovoltaic support, including the maximum deflection at mid-span, maximum torsion angle, cable force reserve coefficient, and structural dynamic characteristics. The target working state reflects the requirements for the installation safety and structural performance of the photovoltaic modules, and serves as the design driving basis for subsequent bidirectional pretension inversion. Subsequently, a parametric numerical model of the bidirectional cable-net system is established, and key design parameters are systematically sampled, including the pretension Tm of the longitudinal main load-bearing cable 1, the pretension Ts of the transverse secondary load-bearing cable 2, cable spacing, initial sag, and the effects of wind load and temperature. This generates a structural response sample library covering the entire design space, providing basic data for constructing the mapping model.

[0029] Based on sampled data, a rapid mapping model between bidirectional pretension and structural operating state is established. This model can predict structural deflection, torsion angle, cable force reserve, and dynamic characteristics under any pretension combination. Through the mapping model, the structural performance corresponding to the pretension combination can be quickly obtained, achieving efficient inversion analysis. On this basis, a bidirectional pretension collaborative safety domain is constructed. A two-dimensional parameter space is established with the pretension Tm of the main load-bearing cable 1 as the vertical axis and the pretension Ts of the secondary load-bearing cable 2 as the horizontal axis. Four types of constraint boundaries—upper limit of cable force under wind pressure condition, lower limit of cable force under wind suction condition, photovoltaic array torsional deformation control, and anchorage structure bearing capacity—are mapped to this parameter space, forming a closed feasible region, namely the collaborative safety domain. Pretension combinations located outside the collaborative safety domain are determined to be infeasible solutions.

[0030] according to Figure 12The inversion process utilizes a fast mapping model, taking the target working state as input to invert and solve for the bidirectional pretension combination. By analyzing the impact of different combinations on structural performance, the synergistic coupling mechanism between the main load-bearing cable 1 and the secondary load-bearing cable 2 is revealed. The inverted pretension combination is mapped to a pre-constructed bidirectional pretension synergistic safety domain to determine its feasibility. If the combination is within the safety domain, the pretension can be directly used as the design value. If the combination is not within the safety domain, the pretension parameters are adjusted according to the nearest safety boundary condition. Iterative correction is performed based on the coupling relationship between the pretension Tm of the main load-bearing cable 1 and the pretension Ts of the secondary load-bearing cable 2. After each iteration, the structural working state is re-substituted into the fast mapping model to verify until the pretension combination simultaneously meets the target working state requirements and the safety domain boundary constraints.

[0031] When necessary, a multi-objective optimization strategy can be introduced, with the optimization objectives of minimizing structural deflection and balancing cable force utilization. This involves balancing performance indicators such as deflection, torsion angle, and cable force reserve. Under the premise of ensuring safety under all working conditions, the optimal bidirectional design preload combination is finally determined. The output results are used to guide cable tensioning operations during the construction phase and can also serve as a benchmark threshold for structural safety monitoring during the operation phase.

[0032] In practical engineering applications, this bidirectional cable-net flexible photovoltaic support system can adjust the span and spacing of the main load-bearing cables 1 according to the site topography, and flexibly adjust the elevation of the secondary cable columns 6 to adapt to the elevation differences of complex terrains such as mine pits, valleys, and tidal flats. This allows for the arrangement of large-span continuous photovoltaic arrays while reducing the number of intermediate columns. During system operation, the self-weight of the photovoltaic modules 8 and external wind and snow loads are first transferred to the secondary load-bearing cables 2. The secondary load-bearing cables 2 then evenly transfer the load to each main load-bearing cable 1 through the tetrahedral connection domains 3. The main load-bearing cables 1 then transfer the load to the main cable columns 4 and main cable anchors 5 at both ends, and finally to the foundation through the anchoring foundation. Lateral loads are borne by the lateral anchoring system composed of the secondary load-bearing cables 2, secondary cable columns 6, and secondary cable anchors 7. The bidirectional cable system achieves coordinated force distribution through rigid tetrahedral nodes, jointly resisting structural deformation and torsion, ensuring the operational accuracy of the photovoltaic modules 8 and the long-term structural stability.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A bidirectional cable-net flexible photovoltaic support system for supporting photovoltaic modules (8), characterized in that, It includes the main load-bearing cable (1), the secondary load-bearing cable (2), the tetrahedral connecting area (3), the main cable column (4), the main cable anchor (5), the secondary cable column (6), and the secondary cable anchor (7). Multiple main load-bearing cables (1) and multiple secondary load-bearing cables (2) are provided. The main load-bearing cables (1) are arranged in parallel along the longitudinal direction. Both ends are supported by the main cable column (4) and anchored to the foundation by the main cable anchor (5). Multiple tetrahedral connection domains (3) are provided. In each tetrahedral connection domain (3), two opposite vertices are fixedly connected to a main load-bearing cable (1), and the other two opposite vertices are fixedly connected to a secondary load-bearing cable (2) with the two vertices located on both sides of the main load-bearing cable (1). The main load-bearing cables (1) and the secondary load-bearing cables (2) are formed into a spatially orthogonal bidirectional cable net through the tetrahedral connection domains (3). The photovoltaic modules (8) are fixed on the secondary load-bearing cables (2) to form a continuous array. The secondary cable column (6) supports the end of the secondary load-bearing cable (2) at the transverse end and is anchored to the foundation by the secondary cable anchor (7). Together with the main cable column (4) and the main cable anchor (5), they form an end anchoring structure.

2. The bidirectional cable-net flexible photovoltaic support system according to claim 1, characterized in that, The main load-bearing cable (1) bears the vertical load transmitted by the secondary load-bearing cable (2) and provides longitudinal torsional stiffness. The secondary load-bearing cable (2) directly bears the self-weight of the photovoltaic module (8) and forms the installation tilt angle of the photovoltaic module by connecting the height difference at both ends. The main load-bearing cable (1) and the secondary load-bearing cable (2) are rigidly coupled through the tetrahedral connection domain (3) to form a spatial collaborative force system.

3. The bidirectional cable-net flexible photovoltaic support system according to claim 1, characterized in that, The tetrahedral connection domain (3) includes four rigid rods (9), a connecting sleeve (10), a connecting cover plate (11), and a connecting bolt (12). The inner ends of the four rigid rods (9) converge and are fixed to the outer wall of the connecting sleeve (10), and the outer ends extend to form the four vertices of the spatial tetrahedron. The connecting sleeve (10) at the four vertices is fixedly connected to the connecting cover plate (11), and the connecting cover plate (11) is fastened to the connecting bolt (12) to clamp the main load-bearing cable (1) and the secondary load-bearing cable (2) respectively.

4. The bidirectional cable-net flexible photovoltaic support system according to claim 1, characterized in that, The main cable column (4) and the secondary cable column (6) are made of concrete or steel and bear vertical pressure and horizontal shear force. The main cable anchor (5) and the secondary cable anchor (7) are made of cables or rods and bear only axial tension. The top elevation of the secondary cable column (6) is adjusted according to the end elevation of the secondary load-bearing cable (2) to match the installation inclination angle.

5. A method for bidirectional pretension synergistic optimization of the bidirectional cable-net flexible photovoltaic support system according to any one of claims 1 to 4, characterized in that, Includes the following steps: Determine the target operating state of the bidirectional cable net support system; Establish a numerical model of the two-way cable net support system, and input the geometry, load, materials and constraints; Construct a rapid mapping model between cable prestress and structural working state; Constructing a bidirectional cable-stayed prestressed collaborative safety domain; Within the collaborative safety domain, determine the bidirectional preload combination that meets the target working state requirements.

6. The bidirectional preload co-optimization method according to claim 5, characterized in that, There is a coupling and synergistic relationship between the pretension of the main load-bearing cable (1) and the pretension of the secondary load-bearing cable (2). When the pretension of the main load-bearing cable (1) increases, the overall stiffness of the structure increases, and the required pretension of the secondary load-bearing cable (2) decreases accordingly. When the pretension of the secondary load-bearing cable (2) increases, the lateral constraint effect is enhanced, and the required pretension of the main load-bearing cable (1) decreases accordingly. The pretension is synergistically configured based on the synergistic function relationship between the two.

7. The bidirectional preload co-optimization method according to claim 5, characterized in that, The structural working state includes one or more of the following: mid-span vertical deflection, structural torsion angle, cable resistance partial factor, and structural dynamic characteristics. A structural response sample set is generated by systematically sampling the bidirectional preload parameter space. A fast mapping model is constructed based on the sample set to achieve rapid prediction of the structural working state.

8. The bidirectional preload co-optimization method according to claim 5, characterized in that, The bidirectional pretension cooperative safety domain is determined by the upper limit boundary of cable force under wind pressure conditions, the lower limit boundary of cable force under wind suction conditions, the control boundary of photovoltaic array torsional deformation, and the control boundary of anchorage structure bearing capacity.

9. The bidirectional preload co-optimization method according to claim 8, characterized in that, The four types of boundaries are mapped to the parameter space formed by the pretension of the main load-bearing cable (1) and the pretension of the secondary load-bearing cable (2), forming a closed cooperative safety domain. The pretension combination located outside the cooperative safety domain is determined to be an infeasible solution.

10. The bidirectional preload co-optimization method according to claim 5, characterized in that, The bidirectional preload combination that satisfies the target working state is obtained by using the fast mapping model inversion. The combination is then mapped to the cooperative safety domain for verification. If the combination is within the safety domain, it is determined as the design preload combination. If the combination is outside the safety domain, it is iteratively corrected until both the target working state and the safety domain constraints are satisfied.

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