Method for constructing dynamic coupled thermal-electric model of floating photovoltaic module

Abstract

The application provides a construction method of a dynamic coupling thermal-electric model of a floating photovoltaic module, comprising the following steps: constructing a power generation model based on a five-parameter single-diode equivalent circuit physical model of the photovoltaic module; establishing a thermal model according to the internal structure of the photovoltaic module, the layout form of the photovoltaic module in a water area, and the heat exchange mode of the photovoltaic module with the surrounding environment; inputting meteorological environment parameters, parameters of the photovoltaic module, and temperatures of each layer of the photovoltaic module at the i moment into the power generation model to obtain power, wherein i is greater than or equal to 0, and i=0 represents an initialized photovoltaic module; inputting heat transfer data of the photovoltaic module in different layout forms in the water area, the meteorological environment parameters, the parameters of the photovoltaic module, and the power into the thermal model to output the temperatures of each layer of the photovoltaic module at the i+1 moment in different layout forms; and obtaining the dynamic coupling thermal-electric model under the condition that the difference between the temperatures of each layer of the photovoltaic module at the i+1 moment and the temperatures at the i moment is less than a preset threshold.

Description

Technical Field

[0001] This invention belongs to the field of clean energy and photovoltaic power generation technology, and in particular relates to a method for constructing a dynamic coupling thermo-electric model of a floating photovoltaic module. Background Technology

[0002] Today, we are at a critical juncture in the energy system transition, and the transition to an ideal net-zero carbon society requires efficient and inexpensive renewable energy. Against this backdrop, the rapid development of the photovoltaic (PV) industry has driven innovation in PV module deployment methods. The emergence of floating PV modules allows them to be deployed on the surface of water bodies such as lakes, reservoirs, ponds, and nearshore waters. However, current research on floating PV modules often neglects the relationship between their thermal and electrical properties, making it impossible to accurately calculate their thermoelectric characteristics. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a method for constructing a dynamic coupling thermo-electric model for floating photovoltaic modules, aiming to solve these problems. The technical solution provided by this invention is as follows.

[0004] According to an embodiment of the present invention, a method for constructing a dynamic coupling thermo-electric model of a floating photovoltaic module includes: constructing a power generation model suitable for a floating photovoltaic module based on a five-parameter single-diode equivalent circuit physical model of the photovoltaic module; and establishing a thermal model suitable for a floating photovoltaic module based on the internal structure of the photovoltaic module, the layout of the photovoltaic module in the water area, and the heat exchange mode between the photovoltaic module and the surrounding environment. This thermal model is used to characterize the energy balance between the layers of the photovoltaic module.

[0005] The following iterative calculation steps are performed to establish a dynamic coupled thermo-electric model for floating photovoltaic modules: Meteorological environmental parameters, photovoltaic module parameters, and the temperature of each layer of the photovoltaic module at time i are input into the power generation model to obtain the power of the photovoltaic module at time i, where i≥0, and i=0 indicates initialization of the photovoltaic module; Heat transfer data of the photovoltaic module in different deployment configurations in the water area, meteorological environmental parameters, photovoltaic module parameters, and power are input into the thermal model to output the temperature of each layer of the photovoltaic module at time i+1 under different deployment configurations; If the difference between the temperature of each layer of the photovoltaic module at time i+1 and the temperature at time i is less than a preset threshold, a dynamic coupled thermo-electric model associated with the thermal model and the power generation model is obtained.

[0006] In embodiments of the present invention, a power generation model suitable for floating photovoltaic modules is constructed based on the five-parameter single-diode equivalent circuit model of a photovoltaic module. Furthermore, based on the structural characteristics of the photovoltaic module and its deployment in the water area, its heat exchange mechanism is analyzed. A thermal model is established considering the multi-layered structure within the photovoltaic module and its correlation with heat conduction, convection, and radiation under different deployment configurations, based on energy balance. During power generation, the photovoltaic module releases heat, which is transferred outwards layer by layer, affecting the module's operating state. Therefore, in establishing the dynamic coupled thermo-electric model of the floating photovoltaic module, meteorological environmental parameters, photovoltaic module parameters, and the photovoltaic module's temperature at time i (i≥0, i=0 indicates initialization of the photovoltaic module) are input into the electrical model, allowing the calculation of the photovoltaic module's power at time i. Subsequently, heat transfer data, meteorological parameters, and photovoltaic module parameters under different deployment configurations in water were input into the thermal model. Based on the multi-layered structure and different deployment configurations of the photovoltaic module, the thermal model could obtain the temperature of each layer of the photovoltaic module at time i+1. The power generation model was iteratively updated while simultaneously updating the temperature of each layer within the photovoltaic module until the difference between the temperature of each layer at time i+1 and the temperature at time i was less than or equal to a preset threshold. This established a dynamically coupled thermo-electrical model associated with both the thermal and power generation models. This dynamically coupled thermo-electrical model fully considers the thermal and electrical feedback relationship of floating photovoltaic modules, achieving coupled analysis of thermal and electrical characteristics. It fills the gap in the effective evaluation of thermal and electrical properties of photovoltaic modules under different deployment configurations, contributing to the accurate evaluation of the performance of floating photovoltaic modules and facilitating their further promotion. Attached Figure Description

[0007] Figure 1 This is a schematic diagram illustrating heat transfer of photovoltaic modules in different deployment configurations within a water area, as described in an embodiment of the present invention.

[0008] Figure 2 This is a schematic diagram of the process for constructing a dynamic coupling thermo-electric model of a photovoltaic module in an embodiment of the present invention;

[0009] Figure 3A This is a comparison chart of the measured power and temperature of the photovoltaic module in spring in Embodiment 1 of the present invention with the power and temperature output by the dynamic coupled thermo-electric model.

[0010] Figure 3B This is a comparison chart of the measured power and temperature of the photovoltaic module in summer in Embodiment 1 of the present invention with the power and temperature output by the dynamic coupled thermo-electric model.

[0011] Figure 3CThis is a comparison chart of the measured power and temperature of the photovoltaic module in autumn in Embodiment 1 of the present invention with the power and temperature output by the dynamic coupled thermo-electric model.

[0012] Figure 3D This is a comparison chart of the measured power and temperature of the photovoltaic module in winter in Embodiment 1 of the present invention with the power and temperature output by the dynamic coupled thermo-electric model. Detailed Implementation

[0013] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the invention. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the invention for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0014] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "comprising" as used herein indicates the presence of features, steps, or operations, but does not exclude the presence or addition of one or more other features.

[0015] When using expressions such as "at least one of A, B, and C," the expression should generally be interpreted in accordance with the meaning commonly understood by a person skilled in the art (e.g., "a system having at least one of A, B, and C" should include, but is not limited to, systems having A alone, having B alone, having C alone, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.). When using expressions such as "at least one of A, B, or C," the expression should generally be interpreted in accordance with the meaning commonly understood by a person skilled in the art (e.g., "a system having at least one of A, B, or C" should include, but is not limited to, systems having A alone, having B alone, having C alone, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.).

[0016] It is well known that high temperatures in photovoltaic (PV) modules negatively impact the semiconductors within them, reducing their lifespan and conversion efficiency. The deployment of floating PV modules near water bodies may lead to lower operating temperatures, raising concerns about their impact on efficiency, a key reason for their significant attention. However, whether lower operating temperatures are a common characteristic of all floating PV modules remains controversial, and their thermal and electrical performance advantages are questioned. Furthermore, research methods for floating PV modules often neglect the relationship between their thermal and electrical properties, or analyze them in isolation. Existing modeling and simulation methods for coupled thermo-electrical characteristics primarily target traditional (land-based) PV modules, simplifying the model to varying degrees and ignoring some heat transfer mechanisms, such as heat exchange between the PV module and the surrounding aquatic environment. This results in existing models failing to adequately consider the coupling and feedback relationships between the thermal and electrical properties of PV modules in aquatic environments, thus hindering accurate evaluation of PV module characteristics.

[0017] In response, this invention fully considers the heat transfer mechanism of floating photovoltaic modules in aquatic environments under different deployment forms, and couples the thermal and electrical performance feedback relationship of photovoltaic modules. Based on this, a method for constructing a dynamic coupled thermal-electric model of floating photovoltaic modules is established, which can realize dynamic and accurate evaluation of the performance of floating photovoltaic modules.

[0018] Specifically, the present invention provides a method for constructing a dynamic coupling thermo-electric model of a floating photovoltaic module, comprising: constructing a power generation model suitable for floating photovoltaic modules based on a five-parameter single-diode equivalent circuit physical model of the photovoltaic module; and establishing a thermal model suitable for floating photovoltaic modules based on the internal structure of the photovoltaic module, the layout of the photovoltaic module in water, and the heat exchange mode between the photovoltaic module and the surrounding environment. This thermal model is used to characterize the energy balance between the layers of the photovoltaic module. Subsequently, the following iterative calculation steps are performed to establish a dynamic coupled thermo-electric model for the floating photovoltaic module: meteorological environmental parameters, photovoltaic module parameters, and the temperature of each layer of the photovoltaic module at time i are input into the power generation model to obtain the power of the photovoltaic module at time i, where i≥0 and i=0 indicates the initialization of the photovoltaic module; heat transfer data of the photovoltaic module in different deployment forms in the water area, meteorological environmental parameters, photovoltaic module parameters, and power are input into the thermal model to output the temperature of each layer of the photovoltaic module at time i+1 under different deployment forms; if the difference between the temperature of each layer of the photovoltaic module at time i+1 and the temperature at time i is less than or equal to a preset threshold, a dynamic coupled thermo-electric model associated with the thermal model and the power generation model is obtained.

[0019] In an embodiment of the present invention, meteorological environmental parameters, photovoltaic (PV) module parameters, and the temperature of the PV module at time i are input into an electrical model established based on a five-parameter single-diode equivalent circuit physical model of the PV module. The power of the PV module at time i can be calculated, where i ≥ 0. i = 0 indicates initialization of the PV module, and the initial temperature of each layer of the PV module can be the ambient temperature. Subsequently, heat transfer data of the PV module under different deployment configurations in the water area, meteorological environmental parameters, and PV module parameters are input into a thermal model. Based on the multi-layered structure of the PV module and its different deployment configurations, the thermal model can obtain the temperature of each layer of the PV module at time i+1. The thermal model establishes a characterization of the energy balance between the layers of the PV module based on the internal structure of the PV module, its deployment configuration in the water area, and the heat exchange method between the PV module and the surrounding environment. By iteratively updating the power of the power generation model and the temperature of each layer of the PV module, until the difference between the temperature of each layer of the PV module at time i+1 and the temperature at time i is less than or equal to a preset threshold, a dynamically coupled thermo-electric model associated with the thermal model and the power generation model is established. This dynamic coupled thermo-electric model fully considers the thermal and electrical feedback relationship of floating photovoltaic modules, realizes the coupled analysis of thermal and electrical performance, fills the gap in the effective evaluation of thermal and electrical properties of photovoltaic modules under different deployment forms, helps to achieve accurate evaluation of the performance of floating photovoltaic modules, and is also conducive to the further promotion of floating photovoltaic modules.

[0020] According to an embodiment of the present invention, before performing the iterative steps, the method further includes: presetting the time increment Δt for establishing the dynamically coupled thermo-electric model and the end time t. max This serves as the calculation parameter for the iterative calculation step. The method for constructing the dynamic coupled thermo-electric model of the floating photovoltaic module further includes: ensuring that the end time t of the dynamic coupled thermo-electric model is greater than or equal to a preset end time t. max In this case, the dynamic coupling thermo-electric model is used to output the power of the photovoltaic module, the temperature of each layer of the photovoltaic module, the current-voltage curve, and the power-voltage curve.

[0021] In an embodiment of the present invention, when the temperature difference between each layer of the photovoltaic module at time i+1 and at time i is less than or equal to a preset threshold, after establishing the dynamic coupled thermo-electric model, the end time of the dynamic coupled thermo-electric model has not yet reached the preset end time t. maxAt this point, iterative calculations are performed on the power generation model and the thermal model using each time increment Δt as the time increment for iterative calculations. The power generation model is used to calculate the saturation current, open-circuit voltage, short-circuit current, and threshold (e.g., maximum) power point voltage and current of the photovoltaic module; the thermal model calculates and outputs the temperature of each layer of the photovoltaic module. This iterative calculation is performed continuously with time increments Δt until the time increment is greater than or equal to the preset end time t for establishing the dynamically coupled thermo-electric model. max Stop the iterative calculation. This method can improve the accuracy of calculations such as output power and photovoltaic module temperature in the dynamically coupled thermo-electric model, which is beneficial for more accurate evaluation of the thermal and electrical performance of photovoltaic modules. It should be noted that the calculation of the power generation model and the thermal model can be carried out within a single time increment Δt, or iterative calculations can be performed over a duration containing multiple time increments Δt.

[0022] For example, at the initial moment (i=0), the photovoltaic (PV) module has not yet started working, and the initial temperature of each layer of the PV module is the ambient temperature, such as 25℃. When the PV module starts working, the meteorological environmental parameters, the parameters of the PV module, and the initial temperatures of each layer of the PV module are input into the power generation model to obtain the power output during the PV module's working time (e.g., 10 minutes, i=10). As the PV module outputs electrical energy, heat transfer occurs simultaneously. By inputting the heat transfer data of the PV module in different deployment configurations in the water area, the meteorological environmental parameters, the parameters of the PV module, and the power output into the thermal model, the temperature of each layer of the PV module during the working time (e.g., 10 minutes, i=10) can be obtained. If the difference between the temperature of each layer of the PV module during the working time and the initial temperature of each layer of the PV module exceeds a preset threshold, then the temperature during the working time (e.g., 10 minutes, i=10) needs to be used as the new iterative calculation parameter to calculate the power output and temperature of each layer of the PV module during the new working time (e.g., after accumulating 20 minutes of operation, i=20). Through continuous iterative calculations, until the temperature difference between each layer of the photovoltaic module at time i+1 and at time i is less than or equal to a preset threshold, the dynamically coupled thermo-electric model associated with the thermal model and the power generation model is obtained. Furthermore, assuming the temperatures of each layer of the photovoltaic module converge, and the end time t of the dynamically coupled thermo-electric model is less than a preset end time t... max In the case of a single time increment Δt, the iteration is performed continuously until the end time t of the dynamically coupled thermo-electric model is greater than or equal to the preset end time t. max Then, through a dynamically coupled thermo-electric model, the power of the photovoltaic module, the temperature of each layer of the photovoltaic module, the current-voltage curve, and the power-voltage curve are output.

[0023] According to an embodiment of the present invention, taking a basic photovoltaic module unit as an example, the internal structure of the photovoltaic module includes: a glass layer, a first ethylene-vinyl acetate copolymer layer (EVA1 layer), a silicon wafer layer, a second ethylene-vinyl acetate copolymer layer (EVA2 layer), and a backsheet layer. Therefore, based on the heat exchange characteristics between the photovoltaic module and its surrounding environment under aquatic conditions, the layout of the photovoltaic module in the water area, and considering the internal structural composition of the photovoltaic module, the present invention analyzes the heat transfer mode of the photovoltaic module and establishes a five-layer thermal model, namely, a thermal model of the glass layer, EVA1 layer, silicon wafer layer, EVA2 layer, and backsheet layer. This thermal model is used to characterize the energy balance of each layer of the photovoltaic module. The parameters of the photovoltaic module include at least one of the following: the number of layers, the thickness of each layer, the material of each layer, the characteristics of each material, the characteristic parameters of the photovoltaic module, the layout of the photovoltaic module in the water area, the tilt angle of the photovoltaic module, and the panel area of ​​the photovoltaic module. For example: material properties include at least one of the following: material density, specific heat, and thermal conductivity; the number of layers in a photovoltaic module is, for example, five; characteristic parameters of a photovoltaic module include: the type of silicon wafer layer in the photovoltaic module (e.g., polycrystalline silicon), the number of photovoltaic modules, and at least one of the following: rated power, open-circuit voltage, short-circuit current, threshold (e.g., maximum) power point current, threshold (e.g., maximum) power point voltage, and power temperature coefficient. Gas phase environmental parameters include at least one of the following: ambient temperature, ambient temperature under the backsheet layer, water temperature, solar irradiance, and wind speed.

[0024] According to embodiments of the present invention, the power generation model applicable to floating photovoltaic modules is derived from the five-parameter single-diode equivalent circuit physical model of the photovoltaic module, resulting in a simplified engineering model suitable for floating photovoltaic modules. A simulation model is then built based on this simplified engineering model, which can be constructed using a programmable software platform. Further, the power generation model of the present invention includes a current model and a voltage model.

[0025] According to an embodiment of the present invention, meteorological environmental parameters, photovoltaic module parameters, and the temperatures of each layer of the photovoltaic module at time i are input into the power generation model to obtain the power of the photovoltaic module at time i, including: solar irradiance G, silicon wafer temperature T C Temperature coefficient of current And the current at the threshold (e.g., maximum) power point of the photovoltaic module under standard test conditions. Solar irradiance G ref Temperature T of photovoltaic modules ref The current is input into the power generation model to obtain the threshold power point current at time i under the silicon wafer temperature of the photovoltaic module. Where ref represents the standard test conditions. It should be noted that at the initial moment (i.e., when i=0), the photovoltaic module has not started working, and the temperature of the photovoltaic module at this time is the ambient temperature.

[0026] Specifically, the current at the threshold power point at the silicon wafer temperature of a photovoltaic module. It can be calculated using the current model shown in equation (1):

[0027] (1).

[0028] For example: solar irradiance G and silicon wafer temperature T after the photovoltaic module has been operating for 10 minutes. C Temperature coefficient of current Once input into the current model, the temperature of the silicon wafer layer of the photovoltaic module at time T can be calculated. C Current at the threshold power point at temperature .

[0029] The voltage temperature coefficient of photovoltaic modules Compensation coefficient Silicon wafer temperature T C Solar irradiance G, and the temperature T of the photovoltaic module under standard test conditions. ref Solar irradiance G ref and the voltage at the threshold power point of photovoltaic modules The voltage at the threshold power point at time i, when input into the power generation model, is obtained. The voltage at the threshold power point of the photovoltaic module at time i under the silicon wafer temperature can be calculated using the voltage model shown in equation (2):

[0030] (2).

[0031] Therefore, based on the current at the threshold power point and voltage The power of the photovoltaic module at time i is obtained, where the power P is calculated using the power generation model shown in equation (3):

[0032] (3).

[0033] According to embodiments of the present invention, a thermal model is used to characterize the energy balance between the layers of a photovoltaic module. Therefore, the thermal model for the five-layer structure of the photovoltaic module of the present invention includes: the energy balance equation of the glass layer, the energy balance equation of the first ethylene-vinyl acetate copolymer layer (EVA1), the energy balance of the silicon wafer layer, the energy balance of the second ethylene-vinyl acetate copolymer layer (EVA2), and the energy balance of the backsheet layer.

[0034] Specifically, the energy balance equation for the glass layer is used to characterize: the heat of the glass layer, the total amount of solar radiation absorbed by the glass layer, and the heat Q transferred between the glass layer and the first ethylene-vinyl acetate copolymer layer. EVA1_g The heat Q transferred between the glass layer and the sky by thermal radiationrad,g_sky And the heat Q transferred by thermal convection between the glass layer and the air. conv,g_a An energy balance exists.

[0035] The energy balance equation for the first ethylene-vinyl acetate copolymer layer is used to characterize: the heat of the first ethylene-vinyl acetate copolymer layer, and the heat Q transferred between the first ethylene-vinyl acetate copolymer layer and the silicon wafer layer through thermal conduction. C_EVA1 The heat Q transferred between the glass layer and the first ethylene-vinyl acetate copolymer layer through thermal conduction. EVA1_g An energy balance exists.

[0036] The energy balance equation for the silicon wafer layer is used to characterize: the heat of the silicon wafer layer, the total amount of solar radiation absorbed by the silicon wafer layer, the power generation, and the heat Q transferred between the first ethylene-vinyl acetate copolymer layer and the silicon wafer layer through thermal conduction. C_EVA1 The heat Q transferred between the silicon wafer layer and the second ethylene-vinyl acetate copolymer layer through thermal conduction. C_EVA2 An energy balance exists.

[0037] The energy balance equation for the second ethylene-vinyl acetate copolymer layer is used to characterize: the heat of the second ethylene-vinyl acetate copolymer layer, and the heat Q transferred between the silicon wafer layer and the second ethylene-vinyl acetate copolymer layer through thermal conduction. C_EVA2 The heat Q transferred between the backing layer and the second ethylene-vinyl acetate copolymer layer through thermal conduction. EVA2_BS An energy balance exists.

[0038] The energy balance of the backsheet layer is used to characterize: the heat of the backsheet layer, and the heat Q transferred between the backsheet layer and the second ethylene-vinyl acetate copolymer layer. EVA2_BS The heat Q transferred between the back panel and the surrounding environment BS_loss An energy balance exists.

[0039] Specifically, the calculation method for the energy balance equation of a five-layer photovoltaic module structure is as follows:

[0040] Glass layer: (4);

[0041] EVA1 layer: (5);

[0042] Silicon wafer layer: (6);

[0043] EVA2 layer: (7);

[0044] Backing layer: (8).

[0045] Among them, c p For specific heat, Where A is the thickness and A is the area of ​​the photovoltaic module panel. For density, For absorption rate, Let G be the transmittance, G be the solar radiation, P be the power of the photovoltaic module, and Q be the power output of the photovoltaic module. EVA1_g Q represents the heat transferred between the EVA1 layer and the glass layer through thermal conduction. rad,g_sky Q represents the heat transferred by thermal radiation between the glass layer and the sky. conv,g_a Q represents the heat transferred by thermal convection between the glass layer and the air. C_EVA1 Q represents the heat transferred between the silicon wafer layer and the EVA1 layer through thermal conduction. C_EVA2 Q represents the heat transferred between the silicon wafer layer and the EVA2 layer through thermal conduction. EVA2_BS Q represents the heat transferred between the EVA2 layer and the backsheet layer through thermal conduction. BS_loss BS represents the heat transferred between the backsheet layer of the photovoltaic module and the surrounding environment; T is temperature, t is time, rad is radiative heat transfer, conv is convective heat transfer, g is glass or glass layer, C is silicon material or silicon wafer layer, and BS is backsheet material or backsheet layer.

[0046] In equation (4), the heat Q transferred between the EVA1 layer and the glass layer is represented by thermal conduction. EVA1_g The result is obtained by the method shown in equation (9):

[0047] (9);

[0048] Among them, T EVA1 For the temperature of EVA1 layer, T g R is the temperature of the glass layer. EVA1_g This represents the thermal resistance between the EVA1 layer and the glass layer.

[0049] In equation (4), the heat Q transferred by thermal radiation between the glass layer and the sky is... rad,g_sky The result is obtained by the method shown in equation (10):

[0050] (10);

[0051] Among them, T sky For sky temperature, R rad,g_sky This represents the thermal resistance between the glass layer and the surrounding atmosphere.

[0052] In equation (4), the heat Q transferred by thermal convection between the glass layer and the air is... conv,g_a The result is obtained by the method shown in equation (11):

[0053] (11);

[0054] Among them, T amb R represents the ambient temperature.conv,g_a The convective thermal resistance of the glass layer.

[0055] In equation (5) or (6), the heat Q transferred between the silicon wafer layer and the EVA1 layer is determined by thermal conduction. C_EVA1 The result is obtained by the method shown in equation (12):

[0056] (12);

[0057] Among them, T C For silicon wafer layer temperature, R C_EVA1 This represents the thermal resistance between the silicon wafer layer and the EVA1 layer.

[0058] In equation (6) or (7), the heat Q transferred between the silicon wafer layer and the EVA2 layer is determined by thermal conduction. C_EVA2 The result is obtained by the method shown in equation (13):

[0059] (13);

[0060] Among them, T EVA2 For the temperature of EVA2 layer, R C_EVA2 This represents the thermal resistance between the silicon wafer layer and the EVA2 layer.

[0061] In equation (7) or (8), the heat Q transferred between the EVA2 layer and the backsheet layer is determined by thermal conduction. EVA2_BS The result is obtained by the method shown in equation (14):

[0062] (14);

[0063] Among them, T BS For backsheet temperature, R EVA2_BS This represents the thermal resistance between EVA2 and the backsheet layer.

[0064] Figure 1 This is a schematic diagram illustrating heat transfer of photovoltaic modules in different deployment configurations within a water area, as described in an embodiment of the present invention.

[0065] According to embodiments of the present invention, such as Figure 1 As shown, the deployment methods of photovoltaic (PV) modules in water bodies include: tilted PV modules (i.e., tilt angle θ > 0°), horizontal PV modules without contact with the water (i.e., tilt angle θ = 0°), and horizontal PV modules with the backsheet in direct contact with the water. These different deployment methods result in various forms of heat transfer Q between the module backsheet layer and the surrounding environment. BS_loss This leads to the heat transfer of the photovoltaic module backsheet layer affecting the temperature of the photovoltaic module silicon wafer layer and the heat transfer of the entire photovoltaic module, thereby affecting the accuracy of the dynamic coupling thermo-electric model evaluation.

[0066] According to an embodiment of the present invention, when the photovoltaic modules are arranged at an angle and the angle of tilt θ > 0°, the heat Q transferred between the module backsheet layer and the surrounding environment is... BS_loss This includes: the heat Q transferred by thermal convection between the backsheet layer and the air below the backsheet layer. conv,BS_ab The heat Q transferred by thermal radiation between the backing layer and the water body rad,BS_w .

[0067] Specifically, when the tilt angle θ of the photovoltaic modules is greater than 0°, Q BS_loss It can be calculated by the method shown in equation (15):

[0068] (15);

[0069] Among them, Q conv,BS_ab Q represents the heat transferred by thermal convection between the backsheet layer and the air below it. rad,BS_w The heat transferred by thermal radiation between the backing layer and the water body.

[0070] The heat Q transferred by thermal radiation between the backing layer and the water body rad,BS_w The radiative heat transfer coefficient between the backplate layer and the water below the backplate layer Area A of photovoltaic module panel, backsheet temperature T BS Water temperature T w The calculation yielded the following result: Specifically, the heat Q transferred between the backing layer and the water body via thermal radiation. rad,BS_w The following calculation method is used to obtain the result:

[0071] (16);

[0072] in, For backsheet temperature, For water temperature, A is the radiative heat transfer coefficient between the backsheet layer and the water body below the backsheet layer, and A is the area of ​​the photovoltaic module panel.

[0073] Furthermore, the radiative heat transfer coefficient between the backplate layer and the water below the backplate layer The result is obtained by the method shown in equation (17):

[0074] (17);

[0075] in, The Stefan-Boltzmann constant is 5.67 × 10⁻⁶. -8 W / m 2 K 4 ), For the emissivity of the backsheet layer of photovoltaic modules, T BS For backsheet layer temperature, Tw The water temperature.

[0076] Furthermore, the emissivity of the backsheet layer of photovoltaic modules The result is obtained by the method shown in equation (18):

[0077] (18);

[0078] in, The emissivity of the backsheet layer, The emissivity of the water body.

[0079] The heat Q transferred by thermal convection between the backsheet layer and the air below the backsheet layer conv,BS_ab The convective heat transfer coefficient between the backplate layer and the air below the backplate layer Area A of photovoltaic module panel, backsheet temperature T BS Ambient temperature under the backsheet layer of photovoltaic modules Calculated.

[0080] Specifically, the heat Q transferred between the backsheet layer and the air below it via thermal convection. conv,BS_ab It is calculated by the method shown in equation (19) below:

[0081] (19);

[0082] in, For the ambient temperature under the backsheet layer of photovoltaic modules, T BS Where A is the backsheet temperature and A is the area of ​​the photovoltaic module panel. The convective heat transfer coefficient is the ratio of the backplate layer to the air below the backplate layer.

[0083] Furthermore, the convective heat transfer coefficient between the backplate layer and the air below the backplate layer... Including: the natural convection heat transfer coefficient between the backplate layer and the air below the backplate layer. Forced convection heat transfer coefficient between the back plate layer and the air below the back plate layer Among them, the natural convection heat transfer coefficient between the backplate layer and the air below the backplate layer. Based on the thermal conductivity k of air a Characteristic length L of photovoltaic modules, Nusselt number of natural convection in the backsheet layer. The forced convection heat transfer coefficient between the backplate layer and the air below the backplate layer is calculated. Based on the thermal conductivity k of air a Characteristic length L of photovoltaic modules, and Nusselt number of forced convection in the backsheet layer. Calculated.

[0084] Specifically, the convective heat transfer coefficient between the backplate layer and the air below the backplate layer. It can be calculated by the methods shown in equations (20) to (22) below:

[0085] (20);

[0086] (twenty one);

[0087] (twenty two);

[0088] in, The natural convection heat transfer coefficient between the backsheet layer and the air beneath the photovoltaic module backsheet layer. The forced convection heat transfer coefficient is the coefficient between the backsheet layer and the air beneath the photovoltaic module backsheet layer. The Nusselt number is the natural convection number of the backsheet layer. k is the Nusselt number for forced convection in the backplane layer. a Let L be the thermal conductivity of air, and L be the characteristic length of the photovoltaic module.

[0089] Furthermore, when the tilt angle of the photovoltaic modules is 2° < θ < 90°, the natural convection Nusselt number of the backsheet layer... It can be calculated by the methods shown in equations (23)-(25):

[0090] (twenty three);

[0091] (twenty four);

[0092] (25);

[0093] Where Ra is the Rayleigh number, Gr is the Grashof number, Pr is the Prandtl number, and g is the gravitational acceleration. θ is the isobaric volume expansion coefficient, and θ is the tilt angle of the photovoltaic module (i.e., the angle between the photovoltaic module and the horizontal plane). kinematic viscosity, k a The thermal conductivity of air. For density, Specific heat capacity.

[0094] When the tilt angle of the photovoltaic modules is 0° < θ ≤ 2°, the natural convection Nusselt number of the backsheet layer is... It can be calculated by the methods shown in equations (26)-(28):

[0095] (26);

[0096] (27);

[0097] (28).

[0098] Furthermore, when the tilt angle of the photovoltaic module is 0° < θ < 90°, the Nusselt number of forced convection in the backsheet layer of the photovoltaic module is... It can be calculated using the methods shown in equations (29) to (31):

[0099] (29);

[0100] , (30);

[0101] (31);

[0102] Where Re is the Reynolds number, and V mod Wind speed at the height where photovoltaic modules are installed.

[0103] According to an embodiment of the present invention, when the photovoltaic module is horizontally arranged and not in contact with water (i.e., the tilt angle θ of the photovoltaic module is 0°), a limited enclosed space is formed between the backsheet layer of the photovoltaic module, the float supporting the photovoltaic module, and the water surface. At this time, the heat Q transferred between the module backsheet layer and the surrounding environment... BS_loss This includes: the heat Q transferred by thermal radiation between the backing layer and the water body. rad,BS_w The heat Q transferred between the backing layer and the water body through thermal conduction between the gas interlayer and the water body. BS_a_w .

[0104] Specifically, when the tilt angle of the photovoltaic module is θ=0°, the heat Q transferred between the module backsheet layer and the surrounding environment is... BS_loss It can be represented as shown in equation (32):

[0105] (33);

[0106] Among them, Q BS_a_w Q represents the heat transferred between the backsheet layer and the water body through thermal conduction between the gas interlayer and the water body. rad,BS_w The heat transferred by thermal radiation between the backing layer and the water body.

[0107] Furthermore, the heat Q transferred by the backing layer and the water body through thermal radiation in equation (32) rad,BS_w The heat Q transferred between the backing layer and the water body through the gas interlayer can be calculated using the method shown in equation (16) above. BS_a_w The heat transfer coefficient h can be achieved by the backing layer through the air interlayer and the water body. BS_a_w Area A of photovoltaic module panel, backsheet temperature T BS Water temperature T wCalculated.

[0108] Specifically, the heat Q transferred between the backsheet layer and the water body through thermal conduction between the gas interlayer and the water body. BS_a_w It can be calculated by the method shown in equation (34):

[0109] (34);

[0110] Among them, h BS_a_w The heat transfer coefficient is the thermal conductivity of the backing layer through the air interlayer and the water.

[0111] Furthermore, the backing layer, through the air interlayer, has a heat transfer coefficient h with the water body. BS_a_w It can be calculated using the method shown in equation (35):

[0112] (35);

[0113] in, The distance from the backsheet of the floating photovoltaic module to the water surface, k a is the thermal conductivity of air.

[0114] According to an embodiment of the present invention, when the photovoltaic modules are arranged horizontally and the backsheet layer of the photovoltaic modules is in direct contact with the water body, the heat Q transferred between the module backsheet layer and the surrounding environment is... BS_loss This includes: the heat Q transferred between the backing layer and the water body through thermal conduction. BS_w The heat Q transferred by thermal convection between the backing layer and the water body conv,BS_w .

[0115] Specifically, when the backsheet layer of a photovoltaic module is in direct contact with water, the heat Q transferred between the module's backsheet layer and the surrounding environment... BS_loss It can be calculated by the method shown in equation (36):

[0116] (36);

[0117] Among them, Q BS_w The heat transferred between the backing layer and the water body, Q conv,BS_w The heat transferred between the backing layer and the water body via thermal convection.

[0118] Furthermore, the heat Q transferred between the backing layer and the water body through thermal conduction... BS_w The thermal conductivity k of the backing layer BS Backing layer thickness Area A of photovoltaic module panel, backsheet temperature T BS Water temperature T w The calculation yielded the following result: Specifically, the heat Q transferred between the backing layer and the water body via thermal conduction. BS_wIt can be calculated using the method shown in equation (37):

[0119] (37);

[0120] Where, k BS For the thermal conductivity of the backing layer, Where A is the thickness of the backsheet layer, A is the area of ​​the photovoltaic module panel, and T is the thickness of the backsheet layer. w For water temperature, T BS This refers to the temperature of the backsheet layer.

[0121] Furthermore, the heat Q transferred by thermal convection between the backsheet layer and the water body below the backsheet layer. conv,BS_w The convective heat transfer coefficient between the backplate layer and the water body can be used to determine the heat transfer efficiency. Area A of photovoltaic module panel, backsheet temperature T BS Water temperature T w Calculated.

[0122] Specifically, the heat Q transferred by thermal convection between the backsheet layer and the water body below the backsheet layer. conv,BS_w It can be calculated using the method shown in equation (38):

[0123] (38);

[0124] in, Where A is the convective heat transfer coefficient between the backsheet layer and the water body, and T is the area of ​​the photovoltaic module panel. W For water temperature, T BS This refers to the temperature of the backsheet layer.

[0125] Furthermore, the convective heat transfer coefficient between the backing layer and the water body It can be calculated using the method shown in equation (39):

[0126] (39);

[0127] Where, k w The thermal conductivity of water, The Nusselt number represents the heat transfer between the backplate layer and the water body via convection.

[0128] Furthermore, the Nusselt number of convective heat transfer between the backplate layer and the water body... It can be calculated using the method shown in equation (40):

[0129] (40);

[0130] in, For the kinematic viscosity of water, For the thermal diffusivity of water, The Reynolds number represents the heat transfer between the backplate layer and the water body via convection.

[0131] Reynolds number of convective heat transfer between the backplate layer and the water body It can be calculated using the method shown in equation (41):

[0132] (41);

[0133] Among them, V w For the flow rate of water, This is the kinematic viscosity of water.

[0134] To make the technical solution of the present invention clearer, the following detailed description is provided in conjunction with specific embodiments and accompanying drawings.

[0135] Example 1

[0136] The floating photovoltaic (PV) modules used in this embodiment 1 are monitored by real-time monitoring equipment installed in City X, Province X. This real-time monitoring equipment includes an IV curve detector for PV power generation monitoring, a meteorological element monitoring station, temperature sensors for the PV modules, water temperature sensors, and an environmental element monitoring device beneath the PV module backsheet layer. The IV curve detector monitors parameters including the PV module current-voltage curve (IV curve), power-voltage curve (PV curve), threshold (e.g., maximum) power point voltage, threshold (e.g., maximum) power point current, open-circuit voltage, and short-circuit current. The meteorological element monitoring station monitors meteorological environmental parameters including irradiance, irradiance at the PV module tilt angle, temperature, humidity, wind speed, wind direction, and rainfall. The data acquisition frequency of all the monitoring equipment used is on the order of minutes.

[0137] The photovoltaic module used in Example 1 has a five-layer internal structure, including a glass layer, an EVA1 layer, a silicon wafer layer, an EVA2 layer, and a backsheet layer. A thermal model is established based on this five-layer structure, in which heat is transferred layer by layer. The following assumptions are made: (i) energy transfer is one-dimensional and time-varying; (ii) heat conduction is uniform along the length and width of the photovoltaic module; (iii) the temperature at the center point of each layer represents the average temperature of that layer; (iv) there is no contact resistance between the layers within the photovoltaic module; (v) there is no heat transfer along the sides of the photovoltaic module; and (vi) the EVA1 layer does not absorb solar radiation. Based on these assumptions, aside from the small amount of solar radiation absorbed by the glass layer, some solar radiation enters the silicon wafer layer to generate electricity through a photoelectric reaction, while the remainder is converted into heat and conducted outwards layer by layer. For floating photovoltaic modules with different deployment configurations, the heat conducted from inside the photovoltaic module undergoes different forms of heat transfer with the external environment, involving heat conduction, heat convection, and heat radiation.

[0138] Therefore, based on the heat exchange characteristics between the photovoltaic module and the surrounding environment under aquatic conditions, the layout of the photovoltaic module in the water, the heat transfer mode of the photovoltaic module, and the internal structure of the photovoltaic module, this invention establishes a five-layer structure (i.e., glass layer, EVA1 layer, silicon wafer layer, EVA2 layer, and backsheet layer). This thermal model is used to characterize the energy balance of each layer of the photovoltaic module, where the energy balance of each layer of the photovoltaic module is shown in equations (4) to (8) above. Furthermore, starting from the five-parameter single-diode equivalent circuit physical model of the photovoltaic module, a power generation model suitable for the photovoltaic module is established. Combining the thermal model and the power generation model, a dynamic coupling thermo-electric model suitable for the photovoltaic module is established.

[0139] Figure 2 This is a schematic diagram of the process for constructing a dynamic coupling thermo-electric model of a photovoltaic module in an embodiment of the present invention.

[0140] like Figure 2 As shown, establishing a dynamic coupled thermo-electric model for photovoltaic modules includes steps S1-S10.

[0141] Step S1: Preset the time increment Δt and end time t for establishing the dynamic coupled thermo-electric model. max , which serve as the calculation parameters for establishing the iterative calculation steps of the dynamic coupling thermo-electric model of photovoltaic modules.

[0142] Step S2: Initialize the temperature and time of each layer of the photovoltaic module.

[0143] Step S3: Input meteorological environmental parameters and photovoltaic module parameters.

[0144] Step S4: In the power generation model, calculate the voltage and current parameters under general conditions to obtain the power;

[0145] Step S5: Calculate the temperature of each layer of the photovoltaic module in the thermal model;

[0146] Step S6: Has the temperature of each layer converged? That is, is the difference between the temperature of each layer of the photovoltaic module at time i+1 (i≥0, i=0 indicates initialization of the photovoltaic module) and the temperature at time i less than or equal to a preset threshold? If the difference between the temperature of each layer of the photovoltaic module at time i+1 and the temperature at time i is greater than the preset threshold, proceed to step S7; if the difference between the temperature of each layer of the photovoltaic module at time i+1 and the temperature at time i is less than or equal to the preset threshold, proceed to step S8.

[0147] Step S7: with = The power and temperature of each layer of the photovoltaic module are calculated iteratively, where j>i, i≥0, j is a positive integer representing the number of iterations; i represents the operating time of the photovoltaic module.

[0148] Step S8: If the temperature difference between each layer of the photovoltaic module at time i+1 and at time i is less than or equal to a preset threshold, determine whether the end time t of the dynamic coupling thermo-electric model is greater than or equal to the preset end time t. max (t≥t) max ?) ? When the end time t of the dynamically coupled thermo-electric model is less than the preset end time t max In the case where the end time t of the dynamic coupling thermo-electric model is greater than or equal to the preset end time t, proceed to step S9; max In the case of S10, proceed to step S10.

[0149] Step S9: Use the preset time increment Δt as the step size, t= The power and temperature of each layer of the photovoltaic module are iteratively calculated using +△t (k≥0, representing time) until the end time t of the dynamic coupled thermo-electric model is greater than or equal to the preset end time t. max .

[0150] Step S10: Output power, temperature of each layer of the photovoltaic module, and plot current-voltage curves and power-voltage curves.

[0151] The material physical properties of each layer of the photovoltaic module of this invention are shown in Table 1.

[0152] Table 1

[0153]

[0154] This invention uses power generation monitoring data from a polycrystalline photovoltaic module with a rated power of 270Wp to verify the dynamic coupling thermo-electric model. Specifically, the characteristic parameters of the photovoltaic module are shown in Table 2.

[0155] Table 2

[0156]

[0157] In the area where the floating photovoltaic modules are located, real-time monitoring data of the floating photovoltaic systems on January 12, April 23, July 30, and September 14, 2021, were used to verify the dynamic coupling thermo-electric model of this invention. The test dates covered four local seasons: winter, spring, summer, and autumn. Specific verification results are as follows: Figures 3A-3D As shown.

[0158] Figure 3A This is a comparison chart of the measured power and temperature of the photovoltaic module in spring in Embodiment 1 of the present invention with the power and temperature output by the dynamic coupled thermo-electric model. Figure 3B This is a comparison chart of the measured power and temperature of the photovoltaic module in summer in Embodiment 1 of the present invention with the power and temperature output by the dynamic coupled thermo-electric model. Figure 3C This is a comparison chart of the measured power and temperature of the photovoltaic module in autumn in Embodiment 1 of the present invention with the power and temperature output by the dynamic coupled thermo-electric model. Figure 3D This is a comparison chart of the measured power and temperature of the photovoltaic module in winter in Embodiment 1 of the present invention with the power and temperature output by the dynamic coupled thermo-electric model.

[0159] like Figures 3A-3D As shown, the simulation calculation data of power and photovoltaic module temperature by the dynamic coupled thermo-electric model are consistent with the real-time monitoring data in different seasons, indicating that the accuracy of the output of the dynamic coupled thermo-electric model of the present invention is high. Table 3 shows the MAE (mean absolute error) and RMSE (standard error) of the dynamic coupled thermo-electric model of the present invention for photovoltaic module temperature and power on test days in four seasons.

[0160] Table 3

[0161]

[0162] As shown in Table 3, the dynamic coupled thermo-electric model of the present invention has low MAE (mean absolute error) and RMSE (standard error) for the temperature and power of photovoltaic modules in the four seasonal test days. The difference between the simulated power value of the dynamic coupled thermo-electric model and the real-time monitored power value is significantly less than 10%, which also shows the accuracy and reliability of the dynamic coupled thermo-electric model established by the present invention.

[0163] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for constructing a dynamic coupled thermal-electric model of a floating photovoltaic module, comprising: constructing a power generation model suitable for the floating photovoltaic module based on a five-parameter single-diode equivalent circuit physical model of the photovoltaic module; establishing a thermal model suitable for the floating photovoltaic module according to an internal structure of the photovoltaic module, a layout form of the photovoltaic module in a water area, and a heat exchange mode of the photovoltaic module with a surrounding environment, the thermal model being used to represent an energy balance between layers of the photovoltaic module; performing the following iterative calculation steps to establish the dynamic coupled thermal-electric model of the floating photovoltaic module: inputting meteorological environment parameters, parameters of the photovoltaic module, and temperatures of layers of the photovoltaic module at i-th moment into the power generation model to obtain a power of the photovoltaic module at i-th moment, wherein i≥0, and i=0 represents an initialized photovoltaic module; inputting heat transfer data of the photovoltaic module in different layout forms in the water area, the meteorological environment parameters, the parameters of the photovoltaic module, and the power into the thermal model to output temperatures of layers of the photovoltaic module at i+1-th moment in different layout forms; obtaining the dynamic coupled thermal-electric model associated with the thermal model and the power generation model when a difference between the temperatures of the layers of the photovoltaic module at i+1-th moment and at i-th moment is less than or equal to a preset threshold value; wherein the heat Q transferred from the backplane layer to the surrounding environment BS_loss comprises: In the case of the photovoltaic module is arranged with an inclination angle θ>0°, the heat Q transferred by the back sheet layer to the surrounding environment BS_loss comprising: the heat Q transferred by the back sheet layer to the air below the back sheet layer by heat convection conv,BS_ab and the heat Q transferred by the back sheet layer to the water body by heat radiation rad,BS_w ; or In the case of the photovoltaic module being arranged at an inclination angle θ = 0°, the heat Q transferred by the back sheet layer to the surrounding environment BS_loss comprising: the heat Q transferred by the back sheet layer to the thermal radiation of a water body rad,BS_w , the heat Q transferred by the back sheet layer to the thermal conduction between the gas interlayer and the water body BS_a_w ; or In the case that the backsheet layer of the photovoltaic module is in direct contact with a body of water, the heat Q transferred by the backsheet layer to the surrounding environment by heat conduction BS_loss comprising: the heat Q transferred by the backsheet layer to the body of water by heat conduction BS_w , the heat Q transferred by the backsheet layer to the body of water by heat convection conv,BS_w ; Wherein, the heat Q transferred by the heat convection of the backsheet layer and the air under the backsheet layer conv,BS_ab The heat convection coefficient of the backsheet layer and the air under the backsheet layer The area A of the photovoltaic module panel, the temperature T of the backsheet layer BS The ambient temperature under the backsheet layer of the photovoltaic module Calculated the heat Q transferred by the backsheet layer to the thermal radiation of the water body rad,BS_w by the backsheet layer and the water body below the backsheet layer , the area A of the photovoltaic module panel, the backsheet layer temperature T BS , the water body temperature T w calculated; The convection heat exchange coefficient of the backboard layer and air under the backboard layer The natural convection heat exchange coefficient of the backboard layer and air under the backboard layer The forced convection heat exchange coefficient of the backboard layer and air under the backboard layer ; Wherein, the natural convection heat exchange coefficient of the backboard layer and the air under the backboard layer The thermal conductivity coefficient k of the air a The characteristic length L of the photovoltaic module, the Nusselt number of the backboard layer natural convection Calculated The forced convection heat transfer coefficient of the back sheet layer and the air under the back sheet layer The thermal conductivity k of air a The characteristic length L of the photovoltaic module, the Nusselt number of the forced convection of the back sheet layer Calculated In the case that the photovoltaic module is arranged at an inclination angle of 2° < θ < 90°, the Nusselt number of the natural convection of the back sheet layer is represented as: ; or In the case that the photovoltaic module is arranged at an inclination angle of 0° < θ ≤ 2°, the Nusselt number of the natural convection of the back sheet layer is represented as: ; wherein Ra is a Rayleigh number; Wherein, the backboard layer transfers heat Q through gas interlayer and water body heat conduction BS_a_w The backboard layer transfers heat through gas interlayer and water body heat conduction coefficient h BS_a_w , the area A of the photovoltaic module panel, the backboard layer temperature T BS , the water body temperature T w The calculation is obtained.

2. The method of claim 1, wherein, before performing the iterative calculation steps, the method further comprises: The preset time increment Δt for establishing the dynamic coupled thermal-electric model and a preset end time t max , as a calculation parameter of the iteration calculation step; and the method further comprises: In a case where the end time t of the dynamic coupled thermal-electric model is greater than or equal to a preset end time t max , the power of the photovoltaic module, the temperature of each layer of the photovoltaic module, the current-voltage curve and the power-voltage curve are output by using the dynamic coupled thermal-electric model.

3. The method of claim 1, wherein, the internal structure of the photovoltaic module comprises a glass layer, a first ethylene-vinyl acetate copolymer layer, a silicon wafer layer, a second ethylene-vinyl acetate copolymer layer, and a backboard layer; the meteorological environment parameters comprise at least one of an ambient temperature, a temperature under the backboard layer, a water temperature, a solar irradiance, and a wind speed; the parameters of the photovoltaic module comprise at least one of a number of layers of the photovoltaic module, thicknesses of layers, materials of layers, characteristics of materials of layers, characteristic parameters of the photovoltaic module, a layout form of the photovoltaic module in the water area, an inclination angle of the photovoltaic module, and a panel area of the photovoltaic module.

4. The method of claim 3, wherein, inputting the meteorological environment parameters, the parameters of the photovoltaic module, and the temperatures of the layers of the photovoltaic module at i-th moment into the power generation model to obtain the power of the photovoltaic module at i-th moment comprises: Compensation of the voltage temperature coefficient of a photovoltaic module , the compensation coefficient , the temperature of the silicon wafer layer T C , the solar irradiance G, and the temperature T of the photovoltaic module under standard test conditions ref , the solar irradiance G ref and the voltage of the threshold power point of the photovoltaic module are input into a power generation model to obtain the voltage of the threshold power point of the photovoltaic module at the temperature of the silicon wafer layer at time i ; solar irradiance G, silicon wafer layer temperature T C , current temperature coefficient , and current of the threshold power point of the photovoltaic module under standard test conditions , solar irradiance G ref , temperature T of the photovoltaic module ref input into the power generation model to obtain the current of the threshold power point under the silicon wafer layer temperature of the photovoltaic module at the i moment ; current according to the threshold power point and voltage to obtain the power of the photovoltaic module at the instant i.

5. The method of claim 4, wherein, the thermal model comprises: An energy balance equation for the glass layer, for characterizing: the heat of the glass layer, the heat of the total solar radiation absorbed by the glass layer, the heat Q of the heat transfer by conduction between the glass layer and the first ethylene-vinyl acetate copolymer layer EVA1_g the heat Q of the heat transfer by thermal radiation between the glass layer and the sky rad,g_sky and the heat Q of the heat transfer by thermal convection between the glass layer and the air conv,g_a there is an energy balance; an energy balance equation for the first ethylene-vinyl acetate copolymer layer to account for: heat from the first ethylene-vinyl acetate copolymer layer, heat Q transferred by thermal conduction between the first ethylene-vinyl acetate copolymer layer and the silicon wafer layer C_EVA1 heat Q transferred by thermal conduction between the glass layer and the first ethylene-vinyl acetate copolymer layer EVA1_g there is an energy balance; An energy balance equation of the silicon wafer layer for representing: heat of the silicon wafer layer, heat transferred by the solar radiation absorbed by the silicon wafer layer, power generation, heat Q transferred by heat conduction between the first ethylene-vinyl acetate copolymer layer and the silicon wafer layer C_EVA1 heat Q transferred by heat conduction between the silicon wafer layer and the second ethylene-vinyl acetate copolymer layer C_EVA2 There is an energy balance; Energy balance equation for the second ethylene-vinyl acetate copolymer layer to account for: heat from the second ethylene-vinyl acetate copolymer layer, heat transferred by conduction between the silicon wafer layer and the second ethylene-vinyl acetate copolymer layer Q C_EVA2 heat transferred by conduction between the backsheet layer and the second ethylene-vinyl acetate copolymer layer Q EVA2_BS There is an energy balance; Energy balance of the backsheet layer for characterizing: heat of the backsheet layer, heat transferred by heat conduction between the backsheet layer and the second ethylene-vinyl acetate copolymer layer Q EVA2_BS heat transferred by heat conduction between the backsheet layer and the surrounding environment Q BS_loss There is an energy balance. 6.The method of claim 1, wherein: the heat Q transferred by the backsheet layer to the water body by thermal conduction BS_w by the thermal conductivity k of the backsheet layer BS the thickness of the backsheet layer the area A of the photovoltaic module panel, the temperature T of the backsheet layer BS the temperature T of the water body w calculated the heat Q convected by the backsheet layer to the water body below the backsheet layer conv,BS_w by the convective heat transfer coefficient between the backsheet layer and the water body , the area A of the photovoltaic module panel, the backsheet layer temperature T BS , the water body temperature T w is calculated.

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