Wind and snow coupling testing device and method for integrated photovoltaic support

Abstract

The invention discloses an integrated photovoltaic support wind and snow coupling testing device and method.The testing device comprises a box body and a measuring assembly, a snowfall simulation mechanism is arranged at the top of the box body with an air inlet and an air outlet formed in the left side and the right side, and an aeroelastic model is arranged at the bottom of the box body and comprises a supporting plate, a supporting frame and a photovoltaic panel; the supporting plate is connected with a bottom plate of the box body through an angle adjusting mechanism; the method comprises the following steps: manufacturing a testing device; the inclination angle of the photovoltaic panel is adjusted, and the dynamic response of the photovoltaic panel in the wind environment and the wind and snow environment is tested; and obtaining a load combination effect value of the photovoltaic panel under the wind and snow coupling effect according to the test data. A photovoltaic support and an integrated photovoltaic module are simulated by making an aeroelastic model, the size of a wind load and a snow load of a photovoltaic panel in a wind and snow coupling environment and parameters under the wind load are obtained, and a wind and snow coupling load combination effect value is obtained. According to the method, the fluid-solid coupling effect between the wind and snow and the photovoltaic module can be comprehensively considered, and the actual behavior of the photovoltaic module under the wind and snow effect is truly reflected.

Description

Technical Field

[0001] The present invention belongs to the technical field of photovoltaic support dynamics testing, and in particular relates to an integrated photovoltaic support wind-snow coupling testing device and method. Background Art

[0002] With the rapid development of my country's photovoltaic industry, numerous problems have arisen during the construction and maintenance of photovoltaic power stations. Failure of the connection points between modules and brackets in strong winds, leading to damage to the photovoltaic system, is a common occurrence. To address these issues, technicians have developed integrated photovoltaic modules. These modules utilize boltless, snap-on steel frames, replacing the aluminum alloy frames of traditional modules. These modules are installed using ground-mounted assembly and crane-mounted installation, significantly increasing construction efficiency.

[0003] Wind tunnel tests are often used in engineering to test the wind resistance of structures. Aeroelastic model testing is an important testing method conducted in wind tunnel laboratories. It simulates the dynamic response process of structures under real wind environments based on similarity theory.

[0004] The current load combination method in existing specifications is for building structures. Given that the main loads during the operation of integrated photovoltaic modules are self-weight load, wind load and snow load, and the wind-snow coupling effect is not considered in the building structure, it is obviously inappropriate to apply the building structure load combination method to photovoltaics. Currently, there is a need for a technology to study the wind-snow coupling load combination of photovoltaic modules. Summary of the Invention

[0005] In order to solve the above problems, the present invention provides an integrated photovoltaic support wind-snow coupling test device and method.

[0006] To achieve the above object, the technical solutions adopted by the present invention are as follows:

[0007] An integrated photovoltaic bracket wind and snow coupling test device includes a box that can be placed in a wind tunnel and a measuring component, wherein the box is provided with an air inlet and an air outlet on the left and right sides, the top of the box is provided with a simulated snowfall mechanism, and the bottom of the box is provided with an aeroelastic model, the aeroelastic model includes a support frame for simulating the photovoltaic bracket and a photovoltaic panel for simulating an integrated photovoltaic component, the support frame is arranged on a support plate, and the support plate is connected to the bottom plate of the box through an angle adjustment mechanism, and the photovoltaic panel is arranged on the support frame; the measuring component is used to test the displacement of the aeroelastic model and the snow distribution on the surface of the photovoltaic panel in a windy and snowy environment, as well as the wind pressure coefficient of the photovoltaic bracket in a windy environment.

[0008] Furthermore, the simulated snowfall mechanism includes a snowmaking machine, a snowfall simulator and a track. The track is arranged at the top of the box, and the snowfall simulator is arranged at the bottom of the snowmaking machine. The snowmaking machine can move along the track, and the snow falls on the photovoltaic panel by adjusting the distance between the snowfall simulator and the photovoltaic panel.

[0009] Furthermore, the rotating mechanism includes a turntable and a rotating motor. The turntable is arranged in the middle of the support plate, and the rotating motor is arranged below the bottom of the support plate. The output end of the rotating motor is connected to the turntable. The photovoltaic panel is rotated by the rotating mechanism to simulate different wind directions.

[0010] Furthermore, the left end of the support plate is provided with flat plate one and the right end is provided with flat plate two, and the flat plate one and flat plate two are respectively rotatably connected to the two ends of the support plate; the angle adjustment mechanism includes a telescopic rod, a slide rail and a slider, the telescopic rod is arranged between flat plate two and flat plate three on the right side of the support plate, the upper end of the telescopic rod is connected to flat plate two, and the lower end of the telescopic rod is connected to flat plate three, the bottom of flat plate three is slidably matched with the slide rail through a slider, and the slide rail is arranged on the bottom plate of the box body, and the inclination angle of the support plate is adjusted by the angle adjustment mechanism, which is used to simulate application scenarios with undulating terrain.

[0011] Furthermore, the box body is made of steel plate, the outer side of the steel plate is provided with a heat insulation board, and the side wall of the box body is provided with an observation window.

[0012] Furthermore, rollers are provided at the bottom of the box.

[0013] Furthermore, the measurement component includes a displacement meter, an acceleration sensor and a laser total station scanner. The displacement meter is used to collect the displacement of the photovoltaic panel surface, the acceleration sensor is used to monitor the acceleration of the photovoltaic panel, and the laser total station scanner is used to measure the thickness of snow on the photovoltaic panel.

[0014] The present invention also provides an integrated photovoltaic support wind and snow coupling test method, comprising the following steps:

[0015] (1) Produce the above-mentioned integrated photovoltaic bracket wind and snow coupling test device;

[0016] (2) Adjust the tilt angle of the photovoltaic panel and test the dynamic response of the photovoltaic panel under wind and snow conditions, including the displacement or acceleration of the photovoltaic panel;

[0017] (3) Calculate the combined load effect of photovoltaic panels under wind and snow coupling scenarios based on test data;

[0018] The calculation formula for the wind load on photovoltaic panels is as follows:

[0019]

[0020] The calculation formula for the snow load on photovoltaic panels is as follows:

[0021] ω×k;

[0022] When the wind load is greater than the snow load, the wind load plays a dominant role, and the formula for the combined load on the photovoltaic panel is as follows:

[0023]

[0024] When the wind load is less than the snow load, the snow load plays a dominant role, and the formula for the combined load on the photovoltaic panel is as follows:

[0025]

[0026] Where: F D Combined effect value of wind-snow coupled load, N;

[0027] D ZG is the deadweight load of the photovoltaic bracket and integrated photovoltaic module, N;

[0028] υ s is the wind pressure coefficient of the photovoltaic panel, obtained by using a rigid model pressure test;

[0029] σ1 is the standard deviation of the displacement or acceleration time history of the photovoltaic panel in the wind-snow coupling scenario, measured by a displacement meter or accelerometer;

[0030] σ2 is the average displacement or acceleration of the photovoltaic panel under the wind-snow coupling scenario, measured by a displacement meter or accelerometer;

[0031] ρ is the air density;

[0032] U S Count the maximum wind speed in the past 25 years for the weather station where the photovoltaic project is located;

[0033] s is the altitude of the meteorological station where the PV project is located;

[0034] z is the altitude of the centerline of the integrated photovoltaic module;

[0035] α is the surface roughness index, α is 0.15;

[0036] ω is the maximum snow pressure within 25 years collected by the meteorological station where the PV project is located;

[0037] k is the snow distribution coefficient on the surface of the photovoltaic panel in the wind-snow coupled scenario, which is calculated based on the thickness of snow on the photovoltaic panel.

[0038] Furthermore, the method for making the gas-elastic model is as follows:

[0039] Determine the geometric scale ratio of the aeroelastic model to be 1:n; determine the similarity parameters of the photovoltaic panel in the aeroelastic model according to the geometric scale ratio of 1:n;

[0040] The similarity parameters include dimensionless frequency, Froude number, Cauchy number, density ratio and damping ratio. According to the similarity criterion, the dimensionless frequency, Froude number, Cauchy number, density ratio and damping ratio of the photovoltaic panel and the integrated photovoltaic module prototype all meet a similarity ratio of 1:1.

[0041] The Froude number formula is Where U is the average wind speed at the height of the integrated photovoltaic module, g is the acceleration of gravity, and B is the chord length of the integrated photovoltaic module. B satisfies the geometric scale ratio 1:n, and the g ratio is 1:1. The ratio of the aeroelastic model to the actual wind speed U of the integrated photovoltaic module is determined to be

[0042] The dimensionless frequency formula is Where f is the vibration frequency of the integrated photovoltaic module, B is the chord length of the integrated photovoltaic module, and U is the average wind speed at the height of the integrated photovoltaic module; B satisfies the geometric scale ratio 1:n, and the wind speed U ratio is The ratio of the vibration frequency of the aeroelastic model to the integrated photovoltaic module is The vibration frequency is the inverse of the period, the period ratio is equal to the time ratio, and is taken as

[0043] The Cauchy number formula is Where E is the elastic modulus of the integrated photovoltaic module, ρ is the air density, U is the average wind speed at the height of the integrated photovoltaic module, and the wind speed U ratio is The air density ρ ratio is 1:1, and the elastic modulus ratio of the photovoltaic panel and the integrated photovoltaic module in the aeroelastic model is determined to be 1:n;

[0044] The density ratio formula is ρ is the air density, ρ s is the density of each component; the air density ρ ratio is 1:1, and the density ratio of the aeroelastic model and the components of the integrated photovoltaic module is 1:1;

[0045] According to the above similar parameters, the geometric scale ratio of the photovoltaic panel in the aeroelastic model is determined to be 1:n, and the time ratio is The mass ratio per unit length is 1:n 2 , the vibration frequency ratio is The bending stiffness ratio is 1:n 5 , the tensile stiffness ratio is 1:n 3 .

[0046] Furthermore, the photovoltaic panels of the aeroelastic model are connected to the support frame through purlins. The support frame includes a column and an oblique beam on its top. The middle part of the oblique beam is connected to the lower part of the column through an oblique brace, and the oblique beam is connected to the column through a connecting piece. An inter-column support is provided between the columns on the same side of the high and low sides, and a base is provided at the bottom of the column. A middle beam is provided between the side beams on the high and low sides of the integrated photovoltaic component, and the middle beam is arranged between two purlins. Longitudinal beams are provided on the oblique sides of both sides of the integrated photovoltaic component.

[0047] Furthermore, the wind pressure coefficient is completed by a rigid model pressure test, the rigid model aeroelastic model is made of rigid components, and the surface of the photovoltaic panel is provided with a pressure measuring hole; a wind pressure sensor is used to test the wind pressure coefficient of the photovoltaic panel.

[0048] Compared with the prior art, the present invention has the following technical advances:

[0049] This method simulates photovoltaic racks and integrated photovoltaic modules by creating an aeroelastic model. A wind-snow coupling scenario is simulated within the enclosure. The wind and snow loads on the photovoltaic panels in this wind-snow coupling environment are then tested and calculated. Key parameters such as displacement, acceleration, and stress under wind load are then determined, ultimately yielding the combined effect of the wind-snow coupling load. This method comprehensively accounts for the fluid-structure coupling effect between wind and photovoltaic modules, thereby more realistically reflecting the actual behavior of photovoltaic modules under wind. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention.

[0051] In the attached figure:

[0052] Figure 1 A schematic structural diagram of an integrated photovoltaic support wind-snow coupling test device provided by an embodiment of the present invention;

[0053] Figure 2 This is a schematic diagram of the installation of an existing integrated photovoltaic module on a photovoltaic bracket;

[0054] Figure 3 for Figure 2 Schematic diagram of the coordination between the integrated photovoltaic modules and the side beams;

[0055] Figure 4 for Figure 2 Schematic diagram of the connection between the center purlin and the longitudinal beam;

[0056] Figure 5 for Figure 2 Schematic diagram of the coordination between the center oblique beam and the purlin;

[0057] Figure 6 for Figure 2 Schematic diagram of the connection between the central column and the inclined beam;

[0058] Figure 7 A comparison of the first-order mode formations of the integrated photovoltaic module prototype and the aeroelastic model;

[0059] Figure 8 A comparison of the second-order modal formations of the integrated photovoltaic module prototype and the aeroelastic model;

[0060] In the picture:

[0061] 1-diagonal beam; 2-purlin; 3-photovoltaic panel; 4-side beam; 5-longitudinal beam; 6-middle beam; 7-column; 8-column support; 9-diagonal brace; 10-address; 11-connector; 12-plate four; 13-snowfall simulator; 14-slider; 15-rotating motor; 16-support frame; 17-telescopic rod; 18-roller; 19-snowmaking machine; 20-track; 21-box; 22-support plate; 23-turntable; 24-plate one; 25-plate two; 26-slide rail; 27-plate three. DETAILED DESCRIPTION

[0062] The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments. The embodiments of the present invention will be described below with reference to the accompanying drawings.

[0063] like Figure 1 The device, shown in Figure 2, is a wind-snow coupling test device for an integrated photovoltaic rack. The device comprises a housing 21 capable of being placed in a wind tunnel and a measurement assembly. The housing 21 is provided with air inlets and outlets on both sides, a simulated snowfall mechanism is located on the top of the housing 21, and an aeroelastic model is located at the bottom of the housing 21. The aeroelastic model comprises a support frame 16 for simulating the photovoltaic rack and a photovoltaic panel 3 for simulating the integrated photovoltaic assembly. The support frame 16 is mounted on a support plate 22, which is connected to the housing 21 via an angle adjustment mechanism. The photovoltaic panel 3 is mounted on the support frame 16. The measurement assembly is used to measure the displacement of the aeroelastic model, the distribution of snow accumulation on the photovoltaic panel surface, and the wind pressure coefficient experienced by the photovoltaic rack in windy conditions. Placing the housing containing the aeroelastic model and the simulated snowfall mechanism in a wind tunnel can simulate both wind and snow conditions, and test the wind load and snow load on the photovoltaic panel in a wind-snow coupling environment, as well as the combined effect of the wind-snow coupling load.

[0064] During specific production, the simulated snowfall mechanism includes a snowmaking machine 19, a snowfall simulator 13, and a track 20. The track 20 is set at the top of the box 21, and the snowfall simulator 13 is set at the bottom of the snowmaking machine 19. The snowmaking machine 19 can move along the track 20, and snow can fall on the photovoltaic panel 3 by adjusting the distance between the snowfall simulator 13 and the photovoltaic panel 3. Among them, the snowmaking machine and the snowfall simulator are both existing technologies and will not be described in detail here. Multiple snowfall simulators are set, and the amount of snow in the test process can be simulated by the number of snowfall simulators turned on and the amount of snow generated by the snowfall simulators, thereby simulating different basic snow pressures. Under different wind speed conditions, it can ensure that snow falls on the surface of the photovoltaic panel. At the same time, the snowfall simulator can move along the top track. When the wind speed is high, the snowfall simulator is farther away from the air-elastic model, and when the wind speed is low, the snowfall simulator is closer to the air-elastic model.

[0065] As a preferred structure, the rotating mechanism includes a turntable 23 and a rotating motor 15. The turntable 23 is arranged in the middle of the support plate 22, and the rotating motor 15 is arranged below the bottom of the support plate 22. The output end of the rotating motor 15 is connected to the turntable 23. The photovoltaic panel 3 is rotated by the rotating mechanism to simulate different wind directions and realize the adjustment of different wind direction angles.

[0066] In a specific embodiment of the present invention, Figure 1 As shown, the support plate 22 is provided with a first plate 24 at the left end and a second plate 25 at the right end. The first and second plates 24 and 25 are rotatably connected to the ends of the support plate 22, respectively. The angle adjustment mechanism includes a telescopic rod 17, a slide rail 26, and a slider 14. The telescopic rod 17 is disposed between the second plate 25 and the third plate 27 on the right side of the support plate 22. The upper end of the telescopic rod 17 is connected to the second plate 25, and the lower end of the telescopic rod 17 is connected to the third plate 27. The bottom of the third plate 27 slides with the slide rail 26 via the slider 14. The slide rail 26 is disposed on the bottom plate of the box 21. The angle adjustment mechanism adjusts the tilt angle of the support plate 22 to simulate an application scenario with undulating terrain. To the right of the second plate 25 is the fourth plate 12. When the second plate 25 is approximately equal in height to the first and fourth plates 24 and 12, the three can be in the same plane. The telescopic rod can be adjusted in height using a hydraulic cylinder or a pneumatic cylinder. By adjusting the height of the telescopic rod, the slope of the support plate can be adjusted. The test slope can be increased step by step starting from zero degrees to simulate actual mountain scenes with different slopes.

[0067] Furthermore, the test device must be used in conjunction with a low-temperature wind tunnel to simulate the low temperatures and corresponding wind conditions found in snowy environments. Rollers at the bottom of the box are used to roll the device into the low-temperature wind tunnel for testing. Specifically, the box 21 is constructed from steel plate, with insulation panels installed on the outside for thermal insulation. Rollers 18 are installed at the bottom of the box 21, and observation windows are provided on the side walls for easy observation of the interior.

[0068] During wind tunnel testing, a simulated snowfall mechanism is required to simulate the geometric parameters, motion parameters, dynamic parameters, accumulation pattern, and time scale of snow particles. Only when these similarities are met can the wind-blown snow phenomenon be simulated. Snow particles are artificially created using a snowmaker. The angle of repose, cohesive properties, and time-varying / temperature-dependent characteristics of the artificial snow particles better meet the accuracy requirements of wind-blown snow testing. In windy weather, the incoming wind moves along the surface of the photovoltaic panel from the windward end to the leeward end. The tilt of the photovoltaic panel and the effects of wind-blown snow cause uneven snow distribution on the panel surface. This test device can be used to study the snow accumulation distribution on the photovoltaic panel surface and determine the snow accumulation distribution coefficient under wind-snow coupled conditions. Furthermore, the device can also determine the snow accumulation distribution on the photovoltaic panel under wind-blown snow conditions under both flat and mountainous conditions by adjusting the slope of the slope.

[0069] In the specific design, the measurement component includes a displacement meter, an acceleration sensor and a laser total station scanner. The displacement meter is used to collect the displacement of the photovoltaic panel surface, the acceleration sensor is used to monitor the acceleration of the photovoltaic panel, and the laser total station scanner is used to measure the thickness of the snow on the photovoltaic panel, and the snow distribution coefficient is obtained by calculation (this is a prior art and will not be described in detail here). During the wind tunnel test, a displacement meter that can be used in a low-temperature environment is used to collect the displacement of the photovoltaic panel surface, and an acceleration sensor used in a low-temperature environment is used to monitor the acceleration of the key node area. The vibration of the photovoltaic panel can be tested by both displacement and acceleration. Among them, the snow distribution coefficient is the ratio of the weight of snow on the photovoltaic module with a certain inclination angle to the weight of snow on the horizontal plane. Due to the influence of structural inclination, wind-blown snow and support structure vibration, the snow on the photovoltaic module will slide to a certain extent, resulting in different snow distribution. The snow distribution on the photovoltaic module can be measured and calculated by a laser total station scanner.

[0070] The above-mentioned integrated photovoltaic bracket wind and snow coupling test device can be used to test the dynamic response of photovoltaic panels under different wind direction angles and different slope scenes (including flat land), and the dynamic amplification coefficient of the structure can be obtained through dynamic response analysis. The dynamic response and dynamic amplification coefficient of photovoltaic panels in pure wind and wind and snow environments can be tested. The dynamic amplification coefficient is the following formula: In a windy environment, photovoltaic panels will produce a vibration pattern similar to the original structure. The dynamic amplification coefficient of the structure can be obtained through dynamic displacement analysis. At the same time, snow will accumulate on the surface of the photovoltaic panels in a windy and snowy environment. The low temperature environment will change the material properties of the photovoltaic panels. In this low-temperature windy and snowy environment, the dynamic response of the photovoltaic panels will also change accordingly. The size of the dynamic amplification coefficient of the photovoltaic panels in the windy and snowy environment can be tested.

[0071] In addition, the above-mentioned test device is used to test the snow distribution coefficient of photovoltaic panels under wind-snow coupled conditions. This is because fixed photovoltaic brackets will vibrate under the action of wind. The vibration of the photovoltaic brackets causes snow to slide off the surface of the photovoltaic modules. Since photovoltaic brackets use less steel than building structures and are relatively flexible, they are prone to wind-induced vibration. Therefore, this test is very necessary for photovoltaic brackets. By rotating the turntable, the snow distribution of photovoltaic brackets can be tested under multiple wind angles. If conditions permit, sharp wedges and rough elements can be placed in front of the test device to simulate a certain degree of wind field. The wind field adopts Class B wind field to simulate application scenarios such as mountains, grasslands, and deserts.

[0072] The present invention also provides an integrated photovoltaic support wind and snow coupling test method, comprising the following steps:

[0073] (1) Produce the above-mentioned integrated photovoltaic bracket wind and snow coupling test device;

[0074] (2) Adjust the tilt angle of the photovoltaic panel on the aeroelastic model to test the dynamic response of the photovoltaic panel under wind and snow conditions, including the displacement or acceleration of the photovoltaic panel;

[0075] (3) Since the photovoltaic panels need to consider the snow load and temperature load acting on the photovoltaic panels during the wind-snow coupling process, which causes the dynamic characteristics of the photovoltaic panels to change, the dynamic amplification coefficient of the photovoltaic panels in the wind-snow coupling environment should be given. At the same time, the wind vibration coefficient (i.e., dynamic amplification coefficient) of the photovoltaic panels in the pure wind environment should be given. In addition, the distribution of snow on the photovoltaic panels in the wind environment will cause differences in the snow accumulation on the surface of the photovoltaic panels due to the wind-blown snow effect and wind-induced vibration. However, the wind-snow coupling effect of photovoltaic panels is not considered in the current Chinese "Building Structure Load Code" and the American Civil Engineering Code ASCE. The main loads of photovoltaic panels are their own gravity load, wind load, and snow load.

[0076] Calculate the combined load effect of the photovoltaic panel under the wind-snow coupling effect based on the test data in step (2);

[0077] The calculation formula for the wind load on photovoltaic panels is as follows:

[0078]

[0079] The calculation formula for the snow load on photovoltaic panels is as follows:

[0080] ω×k;

[0081] When the wind load is greater than the snow load, the wind load plays a dominant role, and the formula for the combined load on the photovoltaic panel is as follows:

[0082]

[0083] When the wind load is less than the snow load, the snow load plays a dominant role, and the formula for the combined load on the photovoltaic panel is as follows:

[0084]

[0085] Where: F D Combined effect value of wind-snow coupled load;

[0086] D ZG It is the deadweight load of the photovoltaic bracket and integrated photovoltaic modules;

[0087] υ s is the wind pressure coefficient of the photovoltaic panel, obtained by using a rigid model pressure test;

[0088] σ1 is the standard deviation of the displacement or acceleration time history of the photovoltaic panel in the wind-snow coupling scenario, measured by a displacement meter or accelerometer;

[0089] σ2 is the average displacement or acceleration of the photovoltaic panel under the wind-snow coupling scenario, measured by a displacement meter or accelerometer;

[0090] ρ is the air density;

[0091] U S Count the maximum wind speed in the past 25 years for the weather station where the photovoltaic project is located;

[0092] s is the altitude of the meteorological station where the PV project is located;

[0093] z is the altitude of the centerline of the integrated photovoltaic module;

[0094] α is the ground roughness index. Since photovoltaic power stations are generally located in open areas such as fields, mountains and deserts, α is taken as 0.15;

[0095] ω is the maximum snow pressure within 25 years collected by the meteorological station where the PV project is located;

[0096] k is the snow distribution coefficient on the surface of the photovoltaic panel in the wind-snow coupled scenario, which is calculated based on the thickness of snow on the photovoltaic panel.

[0097] The wind pressure coefficient is tested using a rigid model pressure test. The rigid model is constructed using rigid components. The difference between a rigid pressure-testing aeroelastic model and an aeroelastic model is that the rigid pressure-testing aeroelastic model uses completely rigid components instead of the scaled components of the aeroelastic model. Pressure holes are provided on the surface of the photovoltaic panel, and the displacement generated by wind loads is extremely small and negligible, making it suitable for testing the wind pressure coefficient of the photovoltaic panel. A wind pressure sensor is used to test the wind pressure coefficient of the photovoltaic panel. Since snow loads do not change the wind pressure coefficient of the photovoltaic panel, snow covering the photovoltaic panel surface will affect the test of the wind pressure coefficient of the photovoltaic panel. Therefore, this process only needs to be performed in a windy environment.

[0098] In a specific embodiment of the present invention, the method for making the gas-elastic model is as follows:

[0099] (1) Measure the main parameters of the aeroelastic model. In this embodiment, the photovoltaic panel 3 adopts a 2×7 photovoltaic unit arrangement. The distance between the front and rear columns is 2.197m. The fixed end span of the support frame is 5m, the cantilever end span is 1.557m, and the total length is 15.301m. The photovoltaic unit adopts 2.275m*1.132m*0.007m. The total chord length of the photovoltaic panel 3 is 4.566m. Figure 2-6 As shown, the photovoltaic panel 3 of the aeroelastic model is connected to the support frame through the purlin 2, and the support frame includes a column 7 and an inclined beam 1 on its top, the middle part of the inclined beam 1 is connected to the lower part of the column 7 through a diagonal brace 9, and the inclined beam 1 is connected to the column 7 through a connector 11; an inter-column support 8 is provided between the columns 7 on the same side on the high and low sides, and a base 10 is provided at the bottom of the column 7; a middle beam is provided between the side beams on the high and low sides of the photovoltaic panel, and the middle beam is arranged between the two purlins, and the oblique sides of the photovoltaic panel are provided with longitudinal beams 5, and the upper and lower horizontal sides are provided with side beams 4, and a plurality of middle beams 6 are provided between the side beams 4 on both sides. This embodiment uses a 2P dual-column photovoltaic support. The photovoltaic panels 3 are inserted into the longitudinal beams 5 of the steel frame. The steel frame is bolted to the purlins 2, which are fixed to the diagonal beams 1. The diagonal beams 1 are connected to the columns 7 via connectors. The bottom of the columns 7 is connected to the foundation. Diagonal braces 9 are installed between the columns 7 and the diagonal beams 1. These components are the main force transmission components. In addition, to ensure the stability of the overall structure, inter-column supports 8 and purlin 2 supports are also provided.

[0100] The above prototype data was used to establish a finite element model. Through modal analysis of vibration mode and the corresponding frequency of each vibration mode, the first-order frequency was 4.98Hz, the second-order frequency was 5.52Hz, and the vibration mode was as follows: Figure 7 、 8 shown.

[0101] (2) Ensure that the aeroelastic model is similar in appearance to the flat uniaxial photovoltaic bracket prototype. Determine the geometric scale ratio of the aeroelastic model based on the dimensions of the flat uniaxial photovoltaic bracket prototype and the cross-sectional dimensions of the wind tunnel laboratory. Determine the geometric dimensions of the aeroelastic model based on the scale ratio. The geometric scale ratio of the aeroelastic model is determined to be 1:10 based on the wind tunnel dimensions and wind speed ratio.

[0102] (3) Determine the dynamic characteristics of the aeroelastic model based on similarity criteria and similarity parameters;

[0103] The aeroelastic model needs to satisfy the following similarity relations:

[0104]

[0105] According to the bending stiffness formula:

[0106] C Ef =EI

[0107] The material selection and cross-sectional dimensions of the main bending members such as the frame 5, purlin 2, and diagonal beam 1 can be determined. The materials and cross-sectional dimensions of these members are shown in Table 2 below:

[0108] Aeroelastic model test parameters

[0109]

[0110] According to the first two-stage formations, the primary deformation is caused by bending of components such as the frame 5, purlin 2, and diagonal beam 1. The bending and tensile and compressive stiffness of columns 7 and diagonal braces 9 are both relatively high, and neither column 7 nor diagonal brace 9 experiences significant deformation in the first two stages. To ensure the required slenderness ratio of columns 7 and diagonal braces 9, their cross-sections can be larger. According to modal calculations, this has no significant impact on the formation and frequency of the aeroelastic model. Column 7 is constructed from stainless steel pipe with an outer diameter of 8mm and a thickness of 2mm. To facilitate drilling, diagonal braces 9 are replaced with L-shaped steel pipes measuring 3mm x 8mm and 0.6mm thick.

[0111] After the cross-sectional dimensions of the test frame model components are determined, a test scale model is established using finite element software. By adjusting the thickness of the photovoltaic panels of the aeroelastic model (adjusting the ratio of the stiffness and mass of the photovoltaic module 3), the formation and frequency of the aeroelastic model are made the same as those of the photovoltaic bracket prototype, such as Figure 7 、 8 The figure shows the formation comparison between the aeroelastic model and the prototype. The two have a high degree of similarity in formation. The first and second order frequencies of the aeroelastic model are 14.95Hz and 18.32Hz respectively, which basically meets the requirements. The similar ratio of , this method can be used to determine the thickness of the photovoltaic panel in the aeroelastic model.

[0112] for Figure 2The aeroelastic model shown here primarily consists of load-bearing components: the frame 5, purlins 2, diagonal beams 1, columns, and diagonal braces 9. The inter-column supports 8 and the purlin 2 supports are structural measures designed to enhance structural stability. Due to the shorter lengths of the components in the scaled model, these components do not significantly contribute to the model's load-bearing capacity. Because the inter-column supports 8 significantly disrupt airflow, they were simulated using ABS to maintain a similar aerodynamic shape.

[0113] (4) Design and manufacture gas-elastic models with similar proportions.

[0114] The similarity parameters include dimensionless frequency, Froude number, Cauchy number, density ratio and damping ratio. According to the similarity criterion, the dimensionless frequency, Froude number, Cauchy number, density ratio and damping ratio of the photovoltaic panel and the integrated photovoltaic module prototype all meet a similarity ratio of 1:1.

[0115] The Froude number formula is Where U is the average wind speed at the height of the integrated photovoltaic module, g is the acceleration of gravity, and B is the chord length of the integrated photovoltaic module. B satisfies the geometric scale ratio 1:n, and the g ratio is 1:1. The ratio of the aeroelastic model to the actual wind speed U of the integrated photovoltaic module can be determined to be

[0116] The dimensionless frequency formula is Where f is the vibration frequency of the integrated photovoltaic module, B is the chord length of the integrated photovoltaic module, and U is the average wind speed at the height of the integrated photovoltaic module; B satisfies the geometric scale ratio of 1:10, and the wind speed U ratio is The ratio of the vibration frequency of the aeroelastic model to the integrated photovoltaic module is The vibration frequency is the inverse of the period, the period ratio is equal to the time ratio, and is taken as

[0117] The Cauchy number formula is Where E is the elastic modulus of the integrated photovoltaic module, ρ is the air density, U is the average wind speed at the height of the integrated photovoltaic module, and the wind speed U ratio is The air density ρ ratio is 1:1, and the elastic modulus ratio of the photovoltaic panel and the integrated photovoltaic module in the aeroelastic model is determined to be 1:10;

[0118] The density ratio formula is ρ is the air density, ρ s is the density of each component; the air density ρ ratio is 1:1, and the density ratio of the aeroelastic model and the components of the integrated photovoltaic module is 1:1;

[0119] According to the above similar parameters, the geometric scale ratio of the photovoltaic panel in the aeroelastic model is determined to be 1:10, and the time ratio is The mass ratio per unit length is 1:10 2 , the vibration frequency ratio is Bending stiffness ratio is 1:10 5 , the tensile stiffness ratio is 1:10 3 .

[0120] In the aeroelastic model, the top of the column is connected to the inclined beam 1 with a triangular connector 11. The top of the column is connected to the triangular connector 11 with an M4 bolt through a hole. The top of the triangular connector 11 is connected to the inclined beam 1 by welding. The two sides of the aeroelastic model diagonal brace 9 are bent and attached to the surface of the inclined beam 1 and the rear column respectively. Holes are punched at the connection position of the components and connected with bolts. The frame 5, purlin 2 and inclined beam 1 of the aeroelastic model are connected by welding. The photovoltaic panel 3 and the frame 5 are connected with acrylic structural adhesive. The inter-column support 8 is tied to the column 7 with nylon rolled tape, and the excess nylon rolled tape is cut off.

[0121] This method places a box containing an aeroelastic model in a wind tunnel, uses a simulated snowfall mechanism and the wind tunnel to simulate a snowstorm scenario, and uses the aeroelastic model to simulate photovoltaic racks and integrated photovoltaic modules. This method then measures the wind and snow loads on the panels under a wind-snow coupled environment, along with their wind-loaded parameters, and ultimately, the combined wind-snow coupled load effect. This method comprehensively considers the fluid-structure coupling effects between wind and snow and photovoltaic panels, accurately reflecting the actual behavior of photovoltaic racks under wind and snow, thus providing data support for photovoltaic projects in wind-snow environments.

[0122] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. An integrated photovoltaic support wind and snow coupling test device, characterized by: It includes a box that can be placed in a wind tunnel and a measuring component, wherein the box is provided with air inlets and air outlets on the left and right sides, the top of the box is provided with a simulated snowfall mechanism, and the bottom of the box is provided with an aeroelastic model, the aeroelastic model includes a support frame for simulating a photovoltaic bracket and a photovoltaic panel for simulating an integrated photovoltaic component, the support frame is arranged on a support plate, and the support plate is connected to the bottom plate of the box through an angle adjustment mechanism, and the photovoltaic panel is arranged on the support frame; the measuring component is used to test the displacement of the aeroelastic model and the distribution of snow on the surface of the photovoltaic panel in a windy and snowy environment, as well as the wind pressure coefficient of the photovoltaic bracket in a windy environment.

2. The integrated photovoltaic support wind and snow coupling test device according to claim 1, characterized in that: The simulated snowfall mechanism includes a snowmaking machine, a snowfall simulator and a track. The track is arranged on the top of the box, and the snowfall simulator is arranged at the bottom of the snowmaking machine. The snowmaking machine can move along the track, and snow falls on the photovoltaic panel by adjusting the distance between the snowfall simulator and the photovoltaic panel.

3. The integrated photovoltaic support wind and snow coupling test device according to claim 1, characterized in that: The rotating mechanism includes a turntable and a rotating motor. The turntable is arranged in the middle of the support plate, and the rotating motor is arranged below the bottom of the support plate. The output end of the rotating motor is connected to the turntable. The photovoltaic panel is rotated by the rotating mechanism to simulate different wind directions.

4. The integrated photovoltaic support wind and snow coupling test device according to claim 1, characterized in that: The left end of the support plate is provided with flat plate one, and the right end is provided with flat plate two, and the flat plate one and flat plate two are respectively rotatably connected to the two ends of the support plate; the angle adjustment mechanism includes a telescopic rod, a slide rail and a slider, the telescopic rod is arranged between flat plate two and flat plate three on the right side of the support plate, the upper end of the telescopic rod is connected to flat plate two, and the lower end of the telescopic rod is connected to flat plate three, the bottom of flat plate three is slidably matched with the slide rail through a slider, and the slide rail is arranged on the bottom plate of the box body. The inclination angle of the support plate is adjusted by the angle adjustment mechanism, which is used to simulate application scenarios with undulating terrain.

5. The integrated photovoltaic support wind and snow coupling test device according to claim 1, characterized in that: The box body is made of steel plates, a heat-insulating plate is provided on the outer side of the steel plates, an observation window is provided on the side wall of the box body, and rollers are provided on the bottom of the box body.

6. The integrated photovoltaic support wind and snow coupling test device according to claim 1, characterized in that: The measurement component includes a displacement meter, an acceleration sensor and a laser total station scanner. The displacement meter is used to collect the displacement of the photovoltaic panel surface, the acceleration sensor is used to monitor the acceleration of the photovoltaic panel, and the laser total station scanner is used to measure the thickness of snow on the photovoltaic panel.

7. A wind-snow coupling test method for an integrated photovoltaic support, characterized in that: The following steps are involved: (1) Producing an integrated photovoltaic support wind and snow coupling test device as described in any one of claims 1 to 6; (2) Adjust the tilt angle of the photovoltaic panel and test the dynamic response of the photovoltaic panel under wind and snow conditions, including the displacement or acceleration of the photovoltaic panel; (3) Calculate the combined load effect of photovoltaic panels under wind and snow coupling scenarios based on test data; The calculation formula for the wind load on photovoltaic panels is as follows: The calculation formula for the snow load on photovoltaic panels is as follows: ω×k; When the wind load is greater than the snow load, the wind load plays a dominant role, and the formula for the combined load on the photovoltaic panel is as follows: When the wind load is less than the snow load, the snow load plays a dominant role, and the formula for the combined load on the photovoltaic panel is as follows: Where: F D Combined effect value of wind-snow coupled load, N; D ZG is the deadweight load of the photovoltaic bracket and integrated photovoltaic module, N; υ s is the wind pressure coefficient of the photovoltaic panel, obtained by using a rigid model pressure test; σ1 is the standard deviation of the displacement or acceleration time history of the photovoltaic panel in the wind-snow coupling scenario, measured by a displacement meter or accelerometer; σ2 is the average displacement or acceleration of the photovoltaic panel under the wind-snow coupling scenario, measured by a displacement meter or accelerometer; ρ is the air density; U S Count the maximum wind speed in the past 25 years for the weather station where the photovoltaic project is located; s is the altitude of the meteorological station where the PV project is located; z is the altitude of the centerline of the integrated photovoltaic module; α is the surface roughness index, α is 0.15; ω is the maximum snow pressure within 25 years collected by the meteorological station where the PV project is located; k is the snow distribution coefficient on the surface of the photovoltaic panel in the wind-snow coupled scenario, which is calculated based on the thickness of snow on the photovoltaic panel.

8. The wind-snow coupling test method for an integrated photovoltaic support according to claim 7, characterized in that: The method for making the gas-elastic model is as follows: Determine the geometric scale ratio of the aeroelastic model to be 1:n; determine the similarity parameters of the photovoltaic panel in the aeroelastic model according to the geometric scale ratio of 1:n; The similarity parameters include dimensionless frequency, Froude number, Cauchy number, density ratio and damping ratio. According to the similarity criterion, the dimensionless frequency, Froude number, Cauchy number, density ratio and damping ratio of the photovoltaic panel and the integrated photovoltaic module prototype all meet a similarity ratio of 1:

1. The Froude number formula is Where U is the average wind speed at the height of the integrated photovoltaic module, g is the acceleration of gravity, and B is the chord length of the integrated photovoltaic module. B satisfies the geometric scale ratio 1:n, and the g ratio is 1:

1. The ratio of the aeroelastic model to the actual wind speed U of the integrated photovoltaic module is determined to be The dimensionless frequency formula is Where f is the vibration frequency of the integrated photovoltaic module, B is the chord length of the integrated photovoltaic module, and U is the average wind speed at the height of the integrated photovoltaic module; B satisfies the geometric scale ratio 1:n, and the wind speed U ratio is The ratio of the vibration frequency of the aeroelastic model to the integrated photovoltaic module is The vibration frequency is the inverse of the period, the period ratio is equal to the time ratio, and is taken as The Cauchy number formula is Where E is the elastic modulus of the integrated photovoltaic module, ρ is the air density, U is the average wind speed at the height of the integrated photovoltaic module, and the wind speed U ratio is The air density ρ ratio is 1:1, and the elastic modulus ratio of the photovoltaic panel and the integrated photovoltaic module in the aeroelastic model is determined to be 1:n; The density ratio formula is ρ is the air density, ρ s is the density of each component; The air density ρ ratio is 1:1, and the density ratio of the aeroelastic model to the components of the integrated photovoltaic module is 1:1; According to the above similar parameters, the geometric scale ratio of the photovoltaic panel in the aeroelastic model is determined to be 1:n, the time ratio is 1:√n, and the unit length mass ratio is 1:n. 2 , the vibration frequency ratio is √n:1; the bending stiffness ratio is 1:n 5 , the tensile stiffness ratio is 1:n 3 .

9. The wind-snow coupling test method for an integrated photovoltaic support according to claim 7, characterized in that: The photovoltaic panels of the aeroelastic model are connected to the support frame through purlins. The support frame includes a column and an inclined beam on its top. The middle part of the inclined beam is connected to the lower part of the column through an inclined brace, and the inclined beam is connected to the column through a connecting piece; an inter-column support is provided between the columns on the same side of the high and low sides, and a base is provided at the bottom of the column; a middle beam is provided between the side beams on the high and low sides of the photovoltaic panel, and the middle beam is arranged between two purlins, and longitudinal beams are provided on the oblique sides of the photovoltaic panel.

10. The wind-snow coupling test method for an integrated photovoltaic support according to claim 7, characterized in that: The wind pressure coefficient is completed by a rigid model pressure test. The rigid model aeroelastic model is made of rigid components, and the surface of the photovoltaic panel is provided with a pressure measuring hole. The wind pressure coefficient of the photovoltaic panel is tested using a wind pressure sensor.

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