A floating photovoltaic time-domain hydrodynamic performance comparative analysis method and system

Abstract

The application discloses a kind of floating photovoltaic time domain hydrodynamic performance comparative analysis method and system, the method of the present application includes obtaining the frequency domain calculation result of floating photovoltaic;Based on the frequency domain calculation result, the hydrodynamic performance of floating photovoltaic under different arrangements is analyzed under the action of irregular wave to obtain the hydrodynamic calculation result of floating photovoltaic;Wherein, the hydrodynamic performance of floating photovoltaic includes motion response condition, connecting structure stress and mooring cable tension;The hydrodynamic calculation result of floating photovoltaic in different arrangements is compared and analyzed to obtain comparative analysis result.The hydrodynamic calculation result of FPV in different arrangements can be designed more stable, more safe floating photovoltaic system by comparative analysis.

Description

Technical Field

[0001] This invention relates to the field of hydrodynamic performance analysis technology, and in particular to a method and system for comparative analysis of the time-domain hydrodynamic performance of floating photovoltaic systems. Background Technology

[0002] In floating photovoltaic (FPV) systems, the design of the floating structure must consider long-term hydrological loads from wind and waves, as well as short-term concentrated loads under extreme weather conditions. This requires establishing hydrodynamic numerical models to study the coupling effects between the structure and the mooring system, between multiple floating structures, and between the structure and the dynamic environment. Combined with physical model experiments, load studies on the floating structure under various combinations of wind, waves, and currents are also necessary. Material selection and durability are crucial: FPV systems require materials capable of meeting 20-30 year service life requirements. Simultaneously, photovoltaic modules and electrical equipment must possess superior weather resistance to withstand harsh marine hydrological and meteorological conditions, such as high temperatures, wind, waves, salt spray, ocean currents, corrosion, biofouling, and extreme natural disasters. Mooring system design is essential: the mooring system must stably anchor the FPV system and withstand the effects of ocean dynamics such as waves. This involves the tension calculation and design of mooring cables to ensure system stability and safety. Environmental impact assessment is also critical: FPV systems may impact the marine ecosystem, such as the potential impact on benthic organisms, plankton, and marine fisheries due to their coverage of large sea areas. Therefore, further demonstration and environmental monitoring and ecological protection measures are needed when designing for large-scale development. Operation and maintenance challenges: Floating offshore facilities require strict consideration of system safety monitoring and contingency plans. The operation and maintenance design needs to facilitate on-site monitoring and replacement of critical and vulnerable components. Furthermore, the dismantling and detachment of floating equipment will affect surrounding waterways and the safe operation of submarine cables, vessels, and dock facilities. Summary of the Invention

[0003] The present invention aims to at least partially solve one of the technical problems in the related art.

[0004] To address this, the present invention proposes a comparative analysis method for the time-domain hydrodynamic performance of floating photovoltaic systems. By comparing and analyzing the hydrodynamic calculation results of FPVs in different arrangements, a more stable and safer floating photovoltaic system can be designed.

[0005] Another objective of this invention is to propose a comparative analysis system for the time-domain hydrodynamic performance of floating photovoltaic systems.

[0006] To achieve the above objectives, this invention proposes a method for comparative analysis of the time-domain hydrodynamic performance of floating photovoltaic systems, comprising:

[0007] Obtain the frequency domain calculation results of the floating photovoltaic system;

[0008] Based on the frequency domain calculation results, the hydrodynamic performance of floating photovoltaic systems under different arrangements is analyzed under the action of irregular waves to obtain the hydrodynamic calculation results of floating photovoltaic systems; wherein, the hydrodynamic performance of floating photovoltaic systems includes motion response, stress on the connecting structure and mooring cable tension.

[0009] The hydrodynamic calculation results of the floating photovoltaic system in different arrangements were compared and analyzed to obtain the comparative analysis results.

[0010] To achieve the above objectives, this invention proposes a floating photovoltaic time-domain hydrodynamic performance comparative analysis system, comprising:

[0011] The frequency domain calculation result acquisition module is used to acquire the frequency domain calculation results of floating photovoltaic systems.

[0012] The hydrodynamic analysis module is used to analyze the hydrodynamic performance of floating photovoltaic systems under different arrangements based on the frequency domain calculation results to obtain the hydrodynamic calculation results of the floating photovoltaic system; wherein, the hydrodynamic performance of the floating photovoltaic system includes motion response, stress on the connecting structure and mooring cable tension.

[0013] The results comparison and analysis module is used to compare and analyze the hydrodynamic calculation results of the floating photovoltaic system in different arrangements to obtain the comparison and analysis results.

[0014] The floating photovoltaic time-domain hydrodynamic performance comparison analysis method and system of this invention improves energy utilization efficiency, saves land resources, enhances system stability and safety, reduces construction and operation costs, and improves system durability and maintainability.

[0015] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0016] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0017] Figure 1 This is a flowchart of a method for comparative analysis of the time-domain hydrodynamic performance of floating photovoltaic systems according to an embodiment of the present invention;

[0018] Figure 2 This is a coordinate system definition diagram according to an embodiment of the present invention;

[0019] Figure 3 This is a diagram showing the numbering of coordinate systems and mooring cables in a single-module simulation according to an embodiment of the present invention;

[0020] Figure 4This is a diagram showing the numbering of the coordinate system and mooring cable in a dual-module simulation according to an embodiment of the present invention;

[0021] Figure 5 This is a diagram defining the connection structure numbers according to an embodiment of the present invention;

[0022] Figure 6 This is a numerical calculation model diagram of the connection structure according to an embodiment of the present invention;

[0023] Figure 7 This is a time-history curve of a partial connection structure according to an embodiment of the present invention;

[0024] Figure 8 This is a diagram showing the numbering of the coordinate system and mooring cables in a six-module simulation according to an embodiment of the present invention;

[0025] Figure 9 The diagram shows the arrangement of each connecting structure in the reference dual-module arrangement according to an embodiment of the present invention. Each connecting structure with a direction parallel to the wave direction is selected for analysis. The diagram shows the connection structure numbering.

[0026] Figure 10 This is a time-history curve diagram of the lower part of the connection structure in the multi-module arrangement according to an embodiment of the present invention;

[0027] Figure 11 This is a comparative analysis diagram of the maximum mooring tension of three different mooring cable arrangements according to an embodiment of the present invention;

[0028] Figure 12 This is a force comparison analysis diagram of the connection structure according to an embodiment of the present invention;

[0029] Figure 13 This is a structural diagram of a floating photovoltaic time-domain hydrodynamic performance comparison and analysis system according to an embodiment of the present invention. Detailed Implementation

[0030] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0031] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0032] The following describes, with reference to the accompanying drawings, a method and system for comparative analysis of the time-domain hydrodynamic performance of floating photovoltaic systems according to embodiments of the present invention.

[0033] The comparative analysis method of the time-domain hydrodynamic performance of floating photovoltaic systems according to embodiments of the present invention is as follows: Figure 1 As shown, it includes:

[0034] S1, obtain the frequency domain calculation results of the floating photovoltaic system;

[0035] S2, Based on the frequency domain calculation results, the hydrodynamic performance of floating photovoltaic systems under different arrangements is analyzed under the action of irregular waves to obtain the hydrodynamic calculation results of floating photovoltaic systems; wherein, the hydrodynamic performance of floating photovoltaic systems includes motion response status, stress on the connecting structure and mooring cable tension.

[0036] S3, compare and analyze the hydrodynamic calculation results of the floating photovoltaic system in different arrangements to obtain the comparative analysis results.

[0037] Specifically, assume that the irregular wave is composed of a series of regular waves with different amplitudes, frequencies, and phases superimposed, where the different phases reflect the randomness of the irregular wave. The formula for an irregular wave is:

[0038]

[0039] In the formula: η is the free wave surface height distribution function, an is the amplitude of a series of regular waves; ωn is the circular frequency period of a series of waves; εn is the phase of a series of waves.

[0040] This invention uses the JONSWAP spectrum for numerical simulation, and its expression is as follows:

[0041]

[0042] In the formula: γ is the peak rise period, σ is the spectral type parameter, when the wave frequency ω is greater than ωp, σ = 0.09; otherwise, σ = 0.07. A = 1 - 0.287ln(γ) is a dimensionless parameter;

[0043] The JONSWAP spectrum is a three-parameter spectrum, mainly determined by the significant peak height HS, the peak period Tp, and the peak elevation factor γ. The relationship between the three is as follows:

[0044]

[0045] Floating photovoltaic systems are typically deployed in shallow nearshore waters. The shallow water wave spectrum is expressed as the product of the deep water wave spectrum and a dimensionless function of the water depth (kd):

[0046] S(ω)=Φ(kd)S0(ω) (5.4)

[0047] In the formula: S0(ω) is the deep-water wave spectrum, a dimensionless function:

[0048]

[0049] The dimensionless quantity in the formula is:

[0050]

[0051] Based on the above theory and measured data, the diving wave spectrum TMA spectrum is obtained:

[0052] S(f)=Φ(kd)S j (f)

[0053] In the formula, Sj(f) is the Jonswap spectrum; Φ(kd) is the correction function, and the suggested formula is:

[0054]

[0055] In the formula: k, d, and f satisfy the dispersion relation.

[0056] Furthermore, a lumped mass model is used to solve for the anchor chain force. This method considers the elongation deformation of the anchor chain while neglecting its bending and torsional stiffness. The central idea is to simplify the anchor chain into a series of massless spring-connected mass points, with the mass of each element evenly distributed among adjacent nodes. According to the principle of static equilibrium, its equilibrium equations are:

[0057] Horizontal direction T j cosr j =T j-1 cosr j-1 (5.9)

[0058] Vertical T j sinr j =T j-1 sinr j-1 +w j (5.10)

[0059] Where Tj is the tension between node j+1; rj is the angle between the j-th segment and the horizontal direction; and wj is the mass of particle j in water.

[0060] The boundary conditions for the uppermost endpoint are:

[0061]

[0062] Where: A is the equivalent cross-sectional area of ​​the anchor chain; E is the elastic modulus of the anchor chain; T is the horizontal force.

[0063] In a multi-module layout, all modules have identical configurations. A global coordinate system OXYZ and local coordinate systems OkXkYkZk for the entire floating photovoltaic system are established, as shown below. Figure 2The overall coordinate system OXYZ is located at the center of the floating photovoltaic system. The local coordinate systems OkXkYkZk of each module are located at the centroid of each module. There are two identical connectors between modules. Each module and the connection structure are represented by Mk (k = 1, 2, ..., n) and Ci (i = 1, 2, ..., 4n-4), where k is the module number and i is the connection structure number.

[0064] Assuming the connecting structure only restricts linear displacement between floating photovoltaic (PV) models, allowing angular displacement, and the connecting structure only bears the force caused by linear displacement, neglecting the torque caused by angular displacement, each floating PV module not only bears wave loads but also the forces transmitted between the modules and the connecting structure. Each module undergoes complex six-freedom operations.

[0065] Degree of motion, introducing the system's degree of freedom vector u k =[u 1 u 2 u 3 u 4 u 5 u 6}:

[0066]

[0067] In the formula: u 1 ~u 6 These represent the six degrees of freedom motion of module Mk: sway, roll, heave, pitch, pitch and yaw.

[0068] Suppose the i-th connection point is located on the k-th module. Then the motion of this connection point can be expressed as:

[0069]

[0070] iii

[0071] In the formula, xk, yk, and zk are the distances from connection point i to the origin of the local coordinate system of module k. The forces generated by the motion of two adjacent modules are:

[0072]

[0073] In the formula, K is the stiffness matrix of the connecting structure, and kx, ky, and kz are the values ​​of the three linear displacement directions, respectively. Δuk,k+1 is the relative displacement between module k and module k+1, which can be expressed as:

[0074]

[0075] In the diagram, i and j are the nodes of the i-th connection structure located in modules k and k+1, respectively, and Tc is the transformation matrix.

[0076] In one embodiment of the present invention, time-domain hydrodynamic analysis is performed on floating photovoltaic systems at similar locations under different arrangement schemes based on frequency-domain hydrodynamic calculation results.

[0077] A time-domain numerical calculation model for a single-module floating photovoltaic system was established. Mooring parameters and relevant sea state parameters were set for the established model. The coordinate system and mooring cable numbering in the single-module simulation are shown below. Figure 3 As shown.

[0078] The single-module floating photovoltaic system exhibits distinct sway, heave, roll, and pitch motion responses under given operating conditions. Due to wind, wave, and current loads, the floating photovoltaic system shows significant sway and heave deviations of 0.61m and 2.51m, respectively. In the heave response, the amplitude is 0.77m. Due to the unique triangular configuration, the pitch response amplitude is 3.74°, representing 45.2% of the roll response amplitude. In the yaw response, the floating photovoltaic system exhibits a yaw deviation of 0.62°.

[0079] In a single-module arrangement, the maximum mooring tension of each mooring cable is calculated. Mooring cables 1-5 and 1-6, positioned on the wave-facing side of the floating photovoltaic system with a 90° wave angle, have maximum mooring tensions of 1023 kN and 976 kN, respectively, with safety factors of 5.47 and 5.74. Mooring cable 1-5, located at the edge of the triangular float, has a maximum mooring tension 10.3% greater than that of mooring cable 1-6. Mooring cable 1-4, positioned on the wave-shielded side of the floating photovoltaic system, has a maximum mooring tension of only 51 kN, and is essentially unloaded during the simulation.

[0080] A dual-module floating photovoltaic time-domain numerical calculation model was established. Mooring system parameters and relevant sea state parameters were set for the established model. The coordinate system and mooring cable numbering in the dual-module simulation are shown below. Figure 4 As shown. Module 1 is selected for analysis based on its placement.

[0081] The motion response of the dual-module floating photovoltaic system is as follows: In the sway response, the sway deviation of the floating photovoltaic system is 0.05m, and the motion response amplitude is 0.06m. In the yaw response, the floating photovoltaic system exhibits a large yaw deviation of 1.75m, with a motion response amplitude of 0.38m. In the heave response, the heave response amplitude of the floating photovoltaic system is 1.29m. Similar to the results under the single-module arrangement, the floating photovoltaic system exhibits a relatively significant yaw motion response under a 90° wave, with a response amplitude of 5.63°, which is 57.9% of the yaw motion response amplitude. Due to the symmetry of the dual-module arrangement, the floating photovoltaic system does not show a significant deviation in the bow roll response, with a motion response amplitude of 0.51°.

[0082] In the dual-module arrangement, the dual-module floating photovoltaic system is symmetrically arranged with waves at a 90° angle. Therefore, there are four mooring cables at both the wave-facing and wave-shielded sections. The mooring cables 2-2 and 2-6, located on the edge of the floating photovoltaic triangle, have significantly higher maximum mooring tensions than the others. Mooring cable 2-6 has a maximum mooring tension of 1478 kN and a safety factor of 3.79, which is 93.2% higher than that of mooring cable 2-4. The maximum mooring tensions at the wave-facing section differ significantly. Mooring cable 2-2 has a maximum mooring tension of 1467 kN, which is 27.1% higher than that of mooring cable 2-1. At the wave-shielded section, the maximum mooring tensions do not differ significantly. Mooring cable 2-3 has a maximum mooring tension of 771 kN, which is only 0.7% higher than that of mooring cable 2-4.

[0083] In a dual-module floating photovoltaic array, the modules are connected by rubber rings to form a floating photovoltaic array. While the rubber rings cannot be directly created in AQWA, nonlinear anchor chains can be defined in the software. When simulating the rubber ring connections, the shape of the rubber rings can be ignored, and only their mechanical properties are considered, assuming the rubber rings are nonlinear elastic ropes. Their mechanical property expressions are as follows:

[0084] F = 250948.13x + 103599.03x 2 -36533.76.x 3 +6490.89.x 4 -381.28.x 5 (6.7)

[0085] In numerical calculations, the dual-module floating photovoltaic inter-plane collision protection pad can be built in AQWA. Since the collision protection pad is also made of rubber, the definitions of the relevant parameters of the rubber ring can refer to the above formulas. The definition of its connection structure number and the numerical calculation model are shown below. Figure 5 and Figure 6 .

[0086] Statistics on the stress of each connecting structure in the floating photovoltaic (PV) system. Observing the data in the table, it can be seen that the maximum stress values ​​of connecting structures No. 1 and No. 4 in the floating PV system are greater than those of other connecting structures. Connecting structure No. 1, which is in direct contact with the waves, experiences a more significant stress compared to other connecting structures. The maximum stress value of connecting structure No. 1 is 957 kN, meeting the strength requirements for connecting structures. Connecting structure No. 3, located in the middle of the floating PV system, experiences a maximum stress of 273 kN, only 28.5% of that of connecting structure No. 1. Floating PV systems experience significant yaw motion when facing 90° waves downwards. Connecting structures No. 1 and No. 4, located on the outermost side of the floating PV system, are the most important connecting structures in the dual-module floating PV system.

[0087] The time-history curves of the force changes of connecting structures 1 and 2 are shown below. Figure 7 During the simulation, the stress on connection structure 2 was relatively stable and there were no obvious sudden changes. However, the stress on connection structure 1 changed more drastically than that on connection structure 2. In the later stage of the simulation, connection structure 1 experienced the maximum stress value.

[0088] A six-module floating photovoltaic time-domain numerical calculation model was established. The coordinate system and mooring cable numbering in the six-module simulation are shown in [reference needed]. Figure 8 As shown. Module 6 is selected for analysis based on its placement.

[0089] The six-degree-of-freedom motion response curves of a six-module floating photovoltaic system. The amplitudes of the swaying and yaw motion responses of the floating photovoltaic system are also relatively smaller compared to the motion response amplitudes in other directions.

[0090] The motion response of the six-module floating photovoltaic system was analyzed. In the sway response, the sway deviation was 0.62m, and the motion response amplitude was 0.21m. In the yaw response, the floating photovoltaic system exhibited a significant yaw deviation of 1.84m, with a motion response amplitude of 0.32m. In the heave response, the heave response amplitude was 0.87m. Similar to the results under a single-module arrangement, the floating photovoltaic system showed a relatively significant sway response under a 90° wave, with a response amplitude of 3.36°, representing 57.4% of the yaw response amplitude. In the bow roll response, the six-module floating photovoltaic system did not show a significant deviation, but the maximum extreme value of the motion response reached 1.32°, with a motion response amplitude of 0.80°.

[0091] The maximum tension of each mooring cable in the six-module layout is as follows: Based on the mooring cable placement, mooring cables 3-9 to 3-12 are all located at the wave-facing position of the floating photovoltaic system. Among them, the maximum mooring tension of mooring cable 3-11 is significantly higher than the other mooring cables, with a maximum tension of 1111 kN and a safety factor of 5.04, meeting the specifications. The maximum mooring tension of mooring cable 3-3 at the wave-facing position is 113 kN, which is 44.5% higher than the maximum tension of other mooring cables at the wave-facing positions.

[0092] The six-module floating photovoltaic array is composed of modules connected by rubber rings. For these rubber ring connections, a non-linear anchor chain is defined in the software. When simulating the rubber ring connections, the shape of the rubber rings can be ignored, and only mechanical properties are considered; the rubber rings are assumed to be a non-linear anchor chain. Due to the large number of connection structures in the six modules, each connection structure needs to be classified during the analysis. Referring to the arrangement of connection structures in the dual-module layout, connection structures with their arrangement direction parallel to the wave direction are selected for analysis. The connection structure numbers are listed below. Figure 9 .

[0093] Statistics on the stress of various connection structures of the floating photovoltaic system under 90° wave conditions. Observing the data in the table, it can be seen that the maximum stress values ​​of connection structures No. 1 and No. 8 in the floating photovoltaic system are greater than those in other conditions. The maximum stress value of connection structure No. 1 is 1452 kN, while the maximum stress of connection structure No. 6 is only 22.3% of that of connection structure No. 1. Connection structure No. 1 is in direct contact with the waves, therefore the stress is more pronounced compared to other connection structures. The connection structures of the floating photovoltaic system located on both sides of the floating body experience more significant stress than other connection structures.

[0094] In a multi-module layout, the stress conditions of the connection structures between the modules of a floating photovoltaic system are quite complex. The stress-time variation curves for connection structures 1 and 6 are shown below. Figure 10 Unlike the dual-module arrangement, the stress changes of connection structures 1 and 6 were unstable, with connection structure 1 experiencing its maximum stress during the mid-simulation period. Among the intermediate connection structures, connection structure 3, located between the two wave-facing modules, experienced a maximum stress of 807 kN, while connection structure 7, located between the two wave-damped modules, experienced a maximum stress of 323 kN. The maximum stress of connection structure 7 was 40.1% of that of connection structure 3.

[0095] The motion response time-history curves of floating photovoltaic systems under three different arrangements are shown. In the sway response, the sway deviation of the floating photovoltaic system in the single-module arrangement is significantly greater than the other two arrangements, with a deviation of 2.51m, which is 33.2% and 38.1% larger than that in the dual-module and six-module arrangements, respectively. However, the sway motion response of the floating photovoltaic system in the single-module and dual-module arrangements is equally severe, with basically the same response amplitude. In the heave response, the response amplitude of the floating photovoltaic system continuously increases with the increase in the number of modules. The motion response amplitude of the floating photovoltaic system in the six-module arrangement is 0.87m, which is 26.6% and 15.2% larger than that in the single-module and dual-module arrangements, respectively.

[0096] In the roll response, the roll motion response amplitudes of the floating photovoltaic system in single-module and dual-module arrangements were 8.28° and 8.71°, respectively, differing by only 4.1%. Due to the characteristics of the triangular configuration, the wind, wave, and current load distribution on the floating photovoltaic system is not uniform, resulting in a more pronounced motion response in the sway direction. The motion response of the floating photovoltaic system in the dual-module arrangement was the most severe, with a response amplitude of 5.04°, which was 19.9% ​​and 69.8% larger than that of the single-module and six-module arrangements, respectively. In the six-module arrangement, the pitch motion response amplitude of the floating photovoltaic system was smaller than that of the other two arrangements, with a response amplitude of 3.36°, which was 79.6% and 58.9% of that of the single-module and dual-module arrangements, respectively.

[0097] We compared and analyzed the mooring cables with the highest mooring tension at the wave-facing and wave-sheltering positions among the three overall arrangement schemes. Figure 11In a single-module layout, select mooring cable 1-6 at the wave-facing position and mooring cable 1-3 at the wave-covered position; in a double-module layout, select mooring cable 2-2 at the wave-facing position and mooring cable 2-7 at the wave-covered position; and in a six-module layout, select mooring cable 3-11 at the wave-facing position and mooring cable 3-3 at the wave-covered position.

[0098] Depend on Figure 10 It can be seen that the maximum mooring tension of the mooring cables at both the wave-facing and wave-covered positions in the dual-module arrangement is greater than that in the other two arrangements. The maximum mooring tension of the mooring cable at the wave-facing position is 1478 kN, which is 44.5% and 33.1% higher than that in the single-module and six-module arrangements, respectively. The maximum mooring tension of the mooring cable at the wave-covered position in the single-module and six-module arrangements is 101 kN and 113 kN, respectively, which is 13.1% and 14.7% of the maximum mooring tension at the wave-covered position in the dual-module arrangement. Although there are relatively more mooring cables on each module in the dual-module arrangement, the symmetry of the floating photovoltaic system in the dual-module arrangement is much lower than that in the single-module and six-module arrangements, and the influence of the multi-module coupling effect is relatively smaller. Therefore, the mooring cable at the wave-covered position of the floating photovoltaic system in the dual-module arrangement experiences more significant stress.

[0099] In the dual-module and six-module layouts, the maximum force on the connection structure with similar layout positions is selected for analysis, see [link to relevant documentation]. Figure 12 .

[0100] Depend on Figure 12 As shown in (a), the stress on each connecting structure in the six-module arrangement is more pronounced than that in the two-module arrangement. The maximum stress on connecting structure 1 is 51.7% greater than the maximum stress on the floating photovoltaic system in the two-module arrangement. In the six-module arrangement, connecting structures 2 and 3, located in the middle of the floating body, experience significant forces. The maximum stress on connecting structure 3 is 807 kN, reaching 63.7% of the maximum stress on connecting structure 4. This is due to the mutual coupling between the modules in the six-module arrangement.

[0101] To facilitate the analysis of the maximum stress values ​​of each connection structure in the dual-module system and the connection structures between the wave-affected modules in the six-module system, the connection structure numbers in the dual-module floating photovoltaic system are redefined. Connection structure numbers 1, 2, 3, and 4 are redefined as connection structures 5, 6, 7, and 8. Figure 12 As shown in (b), except for connection structure No. 6, the maximum force on each connection structure in the six-module arrangement is also greater than that in the two-module arrangement. Among them, the maximum force on connection structure No. 8 is 1321kN, which is 47.9% greater than that in the two-module arrangement. The forces on the connection structures located in the middle of the float are basically the same in both the two-module and six-module arrangements. However, the maximum force on connection structure No. 6 in the two-module arrangement is only 6.4% greater than that in the six-module arrangement.

[0102] In summary, the motion response amplitude of the floating photovoltaic system in all three overall arrangement schemes of this invention meets the design requirements, ensuring the safety of the floating photovoltaic system under given sea conditions. The motion response amplitude of the floating photovoltaic system is relatively small in all three arrangements, and due to the influence of wind and current loads, the floating photovoltaic system exhibits significant offsets in the pitch and sway directions. Due to the special nature of the triangular configuration, the floating photovoltaic system shows a more pronounced motion response in the pitch direction. The pitch motion response amplitude of the floating photovoltaic system in the dual-module arrangement is 5.04°, which is 57.9% of the sway motion response amplitude. The maximum mooring tension of the mooring cable at the wave-facing location is greater in the dual-module arrangement compared to other arrangements, with the maximum mooring tension of mooring cable 2-6 reaching 1478 kN, and a safety factor of 3.79, meeting the design requirements. The maximum mooring tension of each mooring cable at the wave-facing location differs significantly in the dual-module arrangement, with the maximum mooring tension of mooring cable 2-2 reaching 1467 kN, which is 27.1% greater than that of mooring cable 2-1. In both dual-module and six-module arrangements, the maximum stress on the connecting structures of the floating photovoltaic system is located at the wave-facing side of the system. The maximum stress on the connecting structures located on both sides of the floating body's edge is significantly greater than that on other connecting structures. In the six-module arrangement, the maximum stress on the No. 1 connecting structure between the floating photovoltaic units is 1452 kN, which is 51.7% greater than the maximum stress on the connecting structures in the dual-module arrangement. Furthermore, in the six-module arrangement, the stress on the connecting structures between modules on the wave-facing side is more pronounced than that on the wave-damped side.

[0103] like Figure 13 As shown, to achieve the above objectives, this invention proposes a floating photovoltaic time-domain hydrodynamic performance comparison and analysis system 10, comprising:

[0104] Frequency domain calculation result acquisition module 100 is used to acquire the frequency domain calculation results of floating photovoltaic systems;

[0105] The hydrodynamic analysis module 200 is used to analyze the hydrodynamic performance of floating photovoltaic systems under different arrangements based on frequency domain calculation results under irregular wave action to obtain the hydrodynamic calculation results of the floating photovoltaic system; wherein, the hydrodynamic performance of the floating photovoltaic system includes motion response status, stress on the connecting structure and mooring cable tension.

[0106] The result comparison and analysis module 300 is used to compare and analyze the hydrodynamic calculation results of the floating photovoltaic system in different arrangements to obtain the comparison and analysis results.

[0107] The floating photovoltaic time-domain hydrodynamic performance comparison and analysis system according to an embodiment of the present invention

[0108] Improved energy efficiency: Offshore floating photovoltaic (FPV) systems can fully utilize the advantages of open sea surfaces, long hours of sunshine, and high radiation levels to improve the efficiency and output of photovoltaic power generation. Saved land resources: Offshore FPV systems do not require valuable land resources, which is a significant advantage, especially for coastal areas where land resources are scarce. Enhanced system stability and safety: By comparing and analyzing the hydrodynamic calculation results of FPV systems in different arrangements, more stable and safer floating photovoltaic systems can be designed. Reduced construction and operating costs. Improved system durability and maintainability: Selecting appropriate floating materials and structural designs can improve system durability and reduce maintenance costs.

[0109] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0110] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

Claims

1. A method for comparative analysis of the time-domain hydrodynamic performance of floating photovoltaic systems, characterized in that, include: Obtain the frequency domain calculation results of the floating photovoltaic system; Based on the frequency domain calculation results, the hydrodynamic performance of floating photovoltaic systems under different arrangements is analyzed under the action of irregular waves to obtain the hydrodynamic calculation results of floating photovoltaic systems; wherein, the hydrodynamic performance of floating photovoltaic systems includes motion response, stress on the connecting structure and mooring cable tension. The hydrodynamic calculation results of the floating photovoltaic system in different arrangements were compared and analyzed to obtain the comparative analysis results.

2. The method according to claim 1, characterized in that, Assuming an irregular wave is composed of a superposition of regular waves with different amplitudes, frequencies, and phases, where the different phases reflect the randomness of the irregular wave, the formula for an irregular wave is: In the formula: η is the free wave surface height distribution function, an is the amplitude of a series of regular waves; ωn is the circular frequency period of a series of waves; εn is the phase of a series of waves.

3. The method according to claim 1, characterized in that, Numerical simulations were performed using the JONSWAP spectrum, and its expression is as follows: In the formula: γ is the peak rise period, and σ is the spectral type parameter; The JONSWAP spectrum is a three-parameter spectrum, determined by the significant peak height HS, the peak period Tp, and the peak elevation factor γ. The relationship between the three is as follows: The dimensionless quantity in the formula is: The diving wave spectrum TMA spectrum was obtained through theoretical and experimental data: S(f)=Φ(kd)S j (f) In the formula, Sj(f) is the Jonswap spectrum; Φ(kd) is the correction function, and the suggested formula is: In the formula: k, d, and f satisfy the dispersion relation.

4. The method according to claim 1, characterized in that, The anchor chain force is solved using a lumped mass model. According to the principle of static equilibrium, the equilibrium equation is: Horizontal direction: T j cosr j =T j-1 cosr j-1 Vertical: T j sinr j =T j-1 sinr j-1 +w j Where Tj is the tension between node j+1; rj is the angle between the j-th segment and the horizontal direction; and wj is the mass of particle j in water.

5. The method according to claim 4, characterized in that, The boundary conditions for the uppermost endpoint are: Where: A is the equivalent cross-sectional area of ​​the anchor chain; E is the elastic modulus of the anchor chain; T is the horizontal force.

6. The method according to claim 5, characterized in that, Assuming the connecting structure only restricts linear displacement between floating photovoltaic (PV) models but allows angular displacement, and the connecting structure only bears the force caused by linear displacement while ignoring the torque caused by angular displacement, each floating PV module not only bears wave loads but also the forces transmitted between the modules and the connecting structure. Each module undergoes complex six-degree-of-freedom motion, introducing the system's degree-of-freedom vector u. k ={u1, u2, u3, u4, u5, u6}: In the formula: u 1 ~u 6 These represent the six degrees of freedom motion of module Mk: sway, roll, heave, pitch, pitch and yaw.

7. The method according to claim 6, characterized in that, Assuming the i-th connection point is located on the k-th module, the motion of this connection point is expressed as: In the formula, Let i be the distance from the connection point i to the origin of the local coordinate system of module k; the force generated by the motion of two adjacent modules is: In the formula, K is the stiffness matrix of the connecting structure, and kx, ky, and kz are the values ​​of the three linear displacement directions, respectively. Δuk,k+1 is the relative displacement between module k and module k+1, expressed as: In the formula, i and j are the nodes of the i-th connection structure located in modules k and k+1, respectively, and Tc is the transformation matrix.

8. A comparative analysis system for the time-domain hydrodynamic performance of a floating photovoltaic system, characterized in that, include: The frequency domain calculation result acquisition module is used to acquire the frequency domain calculation results of floating photovoltaic systems. The hydrodynamic analysis module is used to analyze the hydrodynamic performance of floating photovoltaic systems under different arrangements based on the frequency domain calculation results to obtain the hydrodynamic calculation results of the floating photovoltaic system; wherein, the hydrodynamic performance of the floating photovoltaic system includes motion response, stress on the connecting structure and mooring cable tension. The results comparison and analysis module is used to compare and analyze the hydrodynamic calculation results of the floating photovoltaic system in different arrangements to obtain the comparison and analysis results.

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