A method and system for calculating irradiance of a bifacial photovoltaic module

Abstract

The application discloses a kind of double-sided photovoltaic module irradiance calculation method, it is characterized in that, including the following steps: step 1, establish the two-dimensional projection geometric model of photovoltaic array, support structure and ground, according to solar hour angle and geographical position, calculate solar elevation angle and azimuth, and utilize two-dimensional projection geometric model, judge whether ground is covered by the shadow of photovoltaic array under current solar position, and generate shade state flag;Step 2, the visual angle factor between each radiation surface is calculated using Hottel cross line method;Step 3, based on light intersection detection algorithm, the shading of support main shaft to direct radiation and ground reflected radiation on the front side is judged, and the front side irradiance and back side irradiance are calculated respectively;Step 4, the front side irradiance and back side irradiance are synthesized into equivalent total irradiance, to significantly improve the accuracy of double-sided photovoltaic module receiving irradiance.

Description

Technical Field

[0001] This invention relates to the field of photovoltaics, and specifically to a method and system for calculating the irradiance of a bifacial photovoltaic module. Background Technology

[0002] Industry estimates suggest that bifacial modules currently account for over 60% of global photovoltaic (PV) capacity. With their widespread application in PV power plants, the demand for high-precision simulations of their power generation has increased significantly to support the design and optimization of PV systems. However, existing simulation tools often have limitations in modeling accuracy or engineering practicality, making it difficult to quickly and reliably calculate the power generation of specific bifacial PV modules in real-world scenarios. The key issues are inaccurate calculations of backsheet irradiance and shading from the mounting system, leading to inaccurate power generation calculations for this type of module.

[0003] To address this issue, a method for calculating the irradiance of bifacial photovoltaic modules is proposed. This method utilizes the Hottel cross-line method to calculate the viewing angle factor between each radiating surface, thereby calculating the back-side irradiance at the cell level, providing a meaningful solution for the engineering design of bifacial photovoltaic power plants. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a method and system for calculating the irradiance of bifacial photovoltaic modules, thereby significantly improving the accuracy of the irradiance received by bifacial photovoltaic modules.

[0005] The technical solution of this invention is: a method for calculating the irradiance of a bifacial photovoltaic module, comprising the following steps: Step 1: Establish a two-dimensional projection geometric model of the photovoltaic array, support structure, and ground. Calculate the solar altitude angle and azimuth angle based on the solar hour angle and geographical location. Using the two-dimensional projection geometric model, determine whether the ground is covered by the shadow of the photovoltaic array under the current solar position, and generate a shading status indicator and name it. If in the shadows, =1, otherwise =0, and its calculation formula is as follows:

[0006] Step 2: Calculate the viewing angle factor between each radiating surface using the Hottel cross-line method; Step 3: Based on the optical cross-section detection algorithm, determine the obstruction of the main shaft of the support to the direct radiation and the reflected radiation from the ground, and calculate the front irradiance respectively. I front With back irradiance I rear ; Step 4: Combine the front irradiance and the back irradiance to form an equivalent total irradiance.I equiv .

[0007] Furthermore, step 1 also includes calculating the ground-received irradiance. I ground This value includes direct irradiance, annular irradiance, and isotropic sky irradiance. The weight of the sky scattering component is determined by the sky openness coefficient of the unshaded ground. Decide.

[0008] Furthermore, in step 2, the Hottel cross-line method is used to calculate the viewing angle factor F for any two parallel or approximately parallel surface segments. A1→A2 : In the two-dimensional projection plane, determine the coordinates A(x) of the endpoint of surface segment 1. A ,z A ) and B(x B ,z B ), and the endpoint coordinates C(x) of surface segment 2. C ,z C ) and D(x D ,z D ); Calculate the distances AD, BC, AC, and BD of the four intersecting line segments, and substitute them into the intersection formula:

[0009] Furthermore, The formula is calculated using the Hottel view factor model as follows:

[0010] in It is the number of the array row in front of the current row; It is the number of array rows following the current row; It is the first x One front-row perspective factor, among which It is the current row itself; It is the first y A rear-row perspective factor; and The calculation formula is as follows:

[0011] In the formula As a general subscript, it represents any row in a photovoltaic array; for example... This represents the point on the ground where the light rays from the lowest point of the photovoltaic cell and the highest point of the adjacent preceding photovoltaic cell are projected.

[0012] Furthermore, in step 3, the back irradiance I rear Components of direct sunlight from the back of the sky I b,rear Backscattering sky component I d,rear Interrow front surface reflection component I row,ref and the ground reflection component on the back I g,rear It consists of four superimposed components, and is calculated separately for each battery cell: Among them, the component of direct sunlight on the back side I b,rear It exists only when the solar altitude angle is very low and the back of the component can be directly exposed to sunlight; Backscattering sky component I d,rear Calculate the area of ​​the solar cells that can be covered by the heat dissipation radiation from the sky. After determining the obstruction caused by the front and rear rows of components and brackets, use the cross-line method to calculate the viewing angle factor corresponding to this area. Multiply by DHI to get the result, as shown in the formula below:

[0013] Interrow front surface reflection component I row,ref Considering the radiation reflected from the front surface of the rear row of modules to the back of the cell; calculate the viewing angle factor of the cell relative to the front surface of the rear row of modules:

[0014] Backside ground reflection component I g,rear Calculate the total ground-received irradiance I ground :

[0015] in, Direct irradiance, For circumpolar irradiance, For isotropic sky diffuse irradiance, The solar zenith angle; The viewing factor of the target area behind and the unobstructed ground consists of two parts: The first part is the non-shaded area directly below the front row of components in the target area on the back, referred to as... :

[0016] The second part consists of the target area on the back and the non-shaded area behind the shadow area, referred to as... :

[0017] The cumulative ground-reflected irradiance is calculated, and its viewing angle factor to the back of the solar cell is calculated using the cross-line method. :

[0018] Considering the impact of the support structure on irradiance, the irradiance of the unshaded areas is summed up:

[0019] in, The total irradiance received by the ground. This refers to the ground reflectivity.

[0020] Furthermore, the total backplane irradiance of a single cell is calculated: the component of direct sky illumination on the backplane is considered. I b,rear Backscattering sky component I d,rear Interrow front surface reflection component I row,ref and the ground reflection component on the back I g,rear The four components are added together to obtain the back irradiance at the center point of the battery. The calculation formula is as follows:

[0021] The average back-side irradiance of the module is calculated by averaging or weighted averaging the back-side irradiance of all representative cells on the module, resulting in the module-level effective back-side irradiance used for subsequent electrical performance calculations. :

[0022] in, The number of photovoltaic cells, The irradiance on the back of any single photovoltaic cell.

[0023] Furthermore, in step 3, the total irradiance on the front side... Direct component from the front Front scattering component and the frontal ground reflection component synthesis; The view factor of the frontal target area and the unobstructed ground unit consists of the following two parts. The first part is the non-shaded area directly below the front-row components of the target area. The formula is as follows:

[0024] The second part consists of the frontal target area and the non-shaded area behind the shadow area. The formula is as follows:

[0025] In the formula and This is a generic symbol that represents the designation of any row of components that has a reflective irradiance effect on the front of the current nth row. Ground received irradiance and viewing angle factor of the target area on the front of the component Depend on and Composition, namely: ; For S g For a ground surface with irradiance = 0, the relationship between the ground received irradiance and the viewing factor of the target area on the front of the component is calculated. The product of these components yields the frontal ground reflection component:

[0026] in The total irradiance received by the ground. This refers to the ground reflectivity.

[0027] Furthermore, there is a superposition of positive radiation:

[0028] in The irradiance shielding coefficient for different support structures.

[0029] Furthermore, the calculated frontal irradiance With back irradiance Combined, utilizing the dihedral factor Obtain the equivalent total irradiance The calculation formula is as follows:

[0030] A system for calculating the irradiance of a bifacial photovoltaic module includes a meteorological data input module for accessing DNI, DHI, and solar position information; The geometric modeling module is used to establish the array's two-dimensional geometric projection; The perspective factor calculation module is implemented based on the cross-line method. The occlusion detection module is used to perform light intersection detection between the support and the shadow; The irradiance synthesis module is used to output the equivalent total irradiance.

[0031] The beneficial technical effects of this invention are: By combining the Hottel cross-line method with the bracket shading light intersection detection algorithm, a two-dimensional high-efficiency view factor model is constructed to calculate the effective irradiance of the front and back sides of the double-sided component. The shading judgment of the main beam structure of the bracket is also introduced, which significantly improves the accuracy and calculation efficiency of irradiance simulation.

[0032] This method includes the following steps: establishing a two-dimensional projection geometric model; calculating the viewing angle factors between the sky, the ground, and the components using the cross-line method; determining the shading of direct sunlight and reflected light from the ground by the main axis of the support based on the light intersection detection algorithm; and calculating the equivalent total irradiance for photovoltaic power prediction. This invention significantly improves the simulation accuracy of bifacial photovoltaic systems under complex shading conditions while ensuring engineering practicality.

[0033] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0034] Figure 1 This is a two-dimensional model diagram of the bifacial photovoltaic array of the present invention; Figure 2 This is a schematic diagram of the hemispherical space and solar angle of the present invention; Figure 3 This is the basic geometric diagram of the cross-line method of the present invention. Detailed Implementation

[0035] In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0036] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate for the embodiments of this application described herein.

[0037] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship described in the embodiments and shown in the accompanying drawings, or the orientation or positional relationship that the product of this invention is usually placed in during use. They are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0038] The ground plane is a horizontal line. The photovoltaic array is simplified to three rows of photovoltaic panels. Each panel is represented as a slanted rectangle. Key parameter annotation: h0 is the installation height, i.e., the vertical distance from the bottom end An of the panel to the ground. β The tilt angle of the photovoltaic panel.

[0039] Shaded Region: The shadow cast from the nth row of boards (An, Bn) onto the ground is labeled as the Shaded Region (SP), and its horizontal range is from Hn to In.

[0040] Unshaded Region 1 (US1): The area directly below the board, from Gn to Hn. Unshaded Region 2 (US2): The area between the right side of the shaded area and the next row of boards, from In to Gn+1. Figure 1 Each geometric intersection is systematically labeled with a letter and a subscript. These are not names, but coordinate points used to precisely describe the relationship between line segment lengths and angles in subsequent formulas.

[0041] like Figures 1-3 As shown, this invention specifically relates to a method for calculating the irradiance of a bifacial photovoltaic module, comprising the following steps: Step 1: Establish a two-dimensional projection geometric model of the photovoltaic array, support structure, and ground. Calculate the solar altitude angle and azimuth angle based on the solar hour angle and geographical location. Using the two-dimensional projection geometric model, determine whether the ground is covered by the shadow of the photovoltaic array under the current solar position, and generate a shading status indicator and name it. If in the shadows, =1, otherwise =0, and its calculation formula is as follows:

[0042] like Figure 2 The upper hemisphere is a hemispherical space. γs represents the solar azimuth angle to be calculated. αs represents the solar altitude angle to be calculated. θz represents the solar zenith angle to be calculated. This diagram shows the angle between the solar ray and the horizon after sunlight enters this space from a point on the hemisphere; this is the solar altitude angle. The solar azimuth angle γs is the angle between the solar ray's projection onto the ground and the north direction, with clockwise being the positive direction. The solar zenith angle θz and the solar altitude angle αs are complementary. Accurate calculations can be performed using parameters such as the latitude of the observation point, solar declination, and solar hour angle.

[0043] Furthermore, step 1 also includes calculating the ground-received irradiance. I ground This value includes direct irradiance, annular irradiance, and isotropic sky irradiance. The weight of the sky scattering component is determined by the sky openness coefficient of the unshaded ground. Decide.

[0044] Step 2: Calculate the viewing angle factor between each radiating surface using the Hottel cross-line method; Cross-line method: Two parallel surfaces or line segments: Figure 2 Draw two infinitely long, parallel line segments to represent two two-dimensional surfaces. These are the transmitting and receiving surfaces, respectively. Each line segment has two endpoints, for a total of four points, usually labeled A, B, C, and D in sequence. Surface 1 endpoints A and B. Surface 2 (representing a region of the ground or sky) endpoints C and D. The arrangement of these points makes line segments AB and CD approximately parallel and spaced apart in cross-section. AC and BD connect the endpoints of one surface to the more distant endpoint of the other surface; these two lines usually intersect. AD and BC connect the endpoints of one surface to the more nearby endpoint of the other surface.

[0045] Furthermore, in step 2, the Hottel cross-line method is used to calculate the viewing angle factor F for any two parallel or approximately parallel surface segments. A1→A2 : In the two-dimensional projection plane, determine the coordinates A(x) of the endpoint of surface segment 1. A ,z A ) and B(x B ,z B ), and the endpoint coordinates C(x) of surface segment 2. C ,z C ) and D(x D ,z D ); Calculate the distances AD, BC, AC, and BD of the four intersecting line segments, and substitute them into the intersection formula:

[0046] Furthermore, The formula is calculated using the Hottel view factor model as follows:

[0047] in It is the number of the array row in front of the current row; It is the number of array rows following the current row; It is the first x One front-row perspective factor, among which It is the current row itself; It is the first y A rear-row perspective factor; and The calculation formula is as follows:

[0048] In the formula As a general subscript, it represents any row in a photovoltaic array; for example... This represents the point on the ground where the light rays from the lowest point of the photovoltaic cell and the highest point of the adjacent preceding photovoltaic cell are projected.

[0049] Step 3: Based on the optical cross-section detection algorithm, determine the obstruction of the main shaft of the support to the direct radiation and the reflected radiation from the ground, and calculate the front irradiance respectively. I front With back irradiance I rear ; Furthermore, in step 3, the back irradiance I rear Components of direct sunlight from the back of the sky I b,rear Backscattering sky component I d,rear Interrow front surface reflection component I row,ref and the ground reflection component on the back I g,rear It consists of four superimposed components, and is calculated separately for each battery cell: Among them, the component of direct sunlight on the back side I b,rear It exists only when the solar altitude angle is very low and the back of the component can be directly exposed to sunlight; Backscattering sky component I d,rear Calculate the area of ​​the solar cells that can be covered by the heat dissipation radiation from the sky. After determining the obstruction caused by the front and rear rows of components and brackets, use the cross-line method to calculate the viewing angle factor corresponding to this area. Multiply by DHI to get the result, as shown in the formula below:

[0050] Interrow front surface reflection component I row,ref Considering the radiation reflected from the front surface of the rear row of modules to the back of the cell; calculate the viewing angle factor of the cell relative to the front surface of the rear row of modules:

[0051] Backside ground reflection component I g,rear Calculate the total ground-received irradiance I ground :

[0052] in, Direct irradiance, For circumpolar irradiance, For isotropic sky diffuse irradiance, The solar zenith angle; The viewing factor of the target area behind and the unobstructed ground consists of two parts: The first part is the non-shaded area directly below the front row of components in the target area on the back, referred to as... :

[0053] The second part consists of the target area on the back and the non-shaded area behind the shadow area, referred to as... :

[0054] The cumulative ground-reflected irradiance is calculated, and its viewing angle factor to the back of the solar cell is calculated using the cross-line method. :

[0055] Considering the impact of the support structure on irradiance, the irradiance of the unshaded areas is summed up:

[0056] in, The total irradiance received by the ground. This refers to the ground reflectivity.

[0057] Furthermore, the total backplane irradiance of a single cell is calculated: the component of direct sky illumination on the backplane is considered. I b,rear Backscattering sky component I d,rear Interrow front surface reflection component I row,ref and the ground reflection component on the back I g,rear The four components are added together to obtain the back irradiance at the center point of the battery. The calculation formula is as follows:

[0058] The average back-side irradiance of the module is calculated by averaging or weighted averaging the back-side irradiance of all representative cells on the module, resulting in the module-level effective back-side irradiance used for subsequent electrical performance calculations. :

[0059] in, The number of photovoltaic cells, The irradiance on the back of any single photovoltaic cell.

[0060] Furthermore, in step 3, the total irradiance on the front side... Direct component from the front Front scattering component and the frontal ground reflection component synthesis; Direct frontal component : The projection of the normal direct irradiance (DNI) onto the normal direction of the module's front surface, calculated based on the solar position. The level of reduction of this component at the cell location is determined based on the type of shading.

[0061] Frontal scattering component The Perez anisotropic scattering model is used to convert the horizontal surface scattered irradiance (DHI) to the tilted surface scattered irradiance. This component is generally not significantly affected by local shading of the support structure.

[0062] Frontal ground reflection component : Calculate the reflection contribution of the unobstructed ground unit to the front of the component.

[0063] The view factor of the frontal target area and the unobstructed ground unit consists of the following two parts. The first part is the non-shaded area directly below the front-row components of the target area. The formula is as follows:

[0064] The second part consists of the target area in front and the non-shaded area behind the shadow area. The formula is as follows:

[0065] In the formula and This is a generic symbol that represents the designation of any row of components that has a reflective irradiance effect on the front of the current nth row. Ground received irradiance and viewing angle factor of the target area on the front of the component Depend on and Composition, namely: ; For S g For a ground surface with irradiance = 0, the relationship between the ground received irradiance and the viewing factor of the target area in front of the component is calculated. The product of these components yields the frontal ground reflection component:

[0066] in The total irradiance received by the ground. This refers to the ground reflectivity.

[0067] Furthermore, there is a superposition of positive radiation:

[0068] in The irradiance shielding coefficients for different support structures.

[0069] Considering the impact of the support structure on irradiance: a conventional support structure has an equivalent irradiance loss of about 0.53%, a double main beam support structure has an equivalent irradiance loss of about 0.25%, and the loss of a single main beam support structure is negligible.

[0070] Step 4: Combine the front irradiance and the back irradiance to form an equivalent total irradiance. I equiv .

[0071] Furthermore, the calculated frontal irradiance With back irradiance Combined, utilizing the dihedral factor Obtain the equivalent total irradiance The calculation formula is as follows:

[0072] In the formula, This is the difaciality factor, which typically ranges from 0.65 to 0.75, depending on the component type.

[0073] A system for calculating the irradiance of a bifacial photovoltaic module includes a meteorological data input module for accessing DNI, DHI, and solar position information; The geometric modeling module is used to establish the array's two-dimensional geometric projection; The perspective factor calculation module is implemented based on the cross-line method. The occlusion detection module is used to perform light intersection detection between the support and the shadow; The irradiance synthesis module is used to output the equivalent total irradiance.

[0074] The above embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and are not intended to limit it. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the scope of the technology disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the scope of protection of the present invention.

Claims

1. A method for calculating the irradiance of a bifacial photovoltaic module, characterized in that, Includes the following steps: Step 1: Establish a two-dimensional projection geometric model of the photovoltaic array, support structure, and ground. Calculate the solar altitude angle and azimuth angle based on the solar hour angle and geographical location. Using the two-dimensional projection geometric model, determine whether the ground is covered by the shadow of the photovoltaic array under the current solar position, and generate a shading status indicator and name it. If in the shadows, =1, otherwise =0, and its calculation formula is as follows: ； Step 2: Calculate the viewing angle factor between each radiating surface using the Hottel cross-line method; Step 3: Based on the optical cross-section detection algorithm, determine the obstruction of the main shaft of the support to the direct radiation and the reflected radiation from the ground, and calculate the front irradiance respectively. I front With back irradiance I rear ; Step 4: Combine the front irradiance and the back irradiance to form an equivalent total irradiance. I equiv .

2. The method for calculating the irradiance of a bifacial photovoltaic module according to claim 1, characterized in that, Step 1 also includes calculating the ground-received irradiance. I ground This value includes direct irradiance, annular irradiance, and isotropic sky irradiance. The weight of the sky scattering component is determined by the sky openness coefficient of the unshaded ground. Decide.

3. The method for calculating the irradiance of a bifacial photovoltaic module according to claim 2, characterized in that, In step 2, the Hottel cross line method is used to calculate the viewing angle factor F for any two parallel or approximately parallel surface segments. A1→A2 : In the two-dimensional projection plane, determine the coordinates A(x) of the endpoint of surface segment 1. A ,z A ) and B(x B ,z B ), and the endpoint coordinates C(x) of surface segment 2. C ,z C ) and D(x D ,z D ); Calculate the distances AD, BC, AC, and BD of the four intersecting line segments, and substitute them into the intersection formula:

4. The method for calculating the irradiance of a bifacial photovoltaic module according to claim 3, characterized in that, The formula is calculated using the Hottel view factor model as follows: ； in It is the number of the array row in front of the current row; It is the number of array rows following the current row; It is the first x One front-row perspective factor, among which It is the current row itself; It is the first y A rear-row perspective factor; and The calculation formula is as follows: ； In the formula As a general subscript, it represents any row in a photovoltaic array; for example... This represents the point on the ground where the light rays from the lowest point of the photovoltaic cell and the highest point of the adjacent preceding photovoltaic cell are projected.

5. The method for calculating the irradiance of a bifacial photovoltaic module according to claim 2, characterized in that, In step 3, the back irradiance I rear Components of direct sunlight from the back of the sky I b,rear Backscattering sky component I d,rear Interrow front surface reflection component I row,ref and the ground reflection component on the back I g,rear It consists of four superimposed components, and is calculated separately for each battery cell: Among them, the component of direct sunlight on the back side I b,rear It exists only when the solar altitude angle is very low and the back of the component can be directly exposed to sunlight; Backscattering sky component I d,rear Calculate the area of ​​the solar cells that can be covered by the heat dissipation radiation from the sky. After determining the obstruction caused by the front and rear rows of components and brackets, use the cross-line method to calculate the viewing angle factor corresponding to this area. Multiply by DHI to get the result, as shown in the formula below: ； Interrow front surface reflection component I row,ref Considering the radiation reflected from the front surface of the rear row of modules to the back of the cell; calculate the viewing angle factor of the cell relative to the front surface of the rear row of modules: ； Backside ground reflection component I g,rear Calculate the total ground-received irradiance I ground : ； in, Direct irradiance, For circumpolar irradiance, For isotropic sky diffuse irradiance, The solar zenith angle; The viewing factor of the target area behind and the unobstructed ground consists of two parts: The first part is the non-shaded area directly below the front row of components in the target area on the back, referred to as... : ； The second part consists of the target area on the back and the non-shaded area behind the shadow area, referred to as... : ； The cumulative ground-reflected irradiance is calculated, and its viewing angle factor to the back of the solar cell is calculated using the cross-line method. : ； Considering the impact of the support structure on irradiance, the irradiance of the unshaded areas is summed up: ； in, The total irradiance received by the ground. This refers to the ground reflectivity.

6. The method for calculating the irradiance of a bifacial photovoltaic module according to claim 5, characterized in that, Calculate the total backplane irradiance of a single cell: include the component of direct sky illumination on the backplane. I b,rear Backscattering sky component I d,rear Interrow front surface reflection component I row,ref and the ground reflection component on the back I g,rear The four components are added together to obtain the back irradiance at the center point of the battery. The calculation formula is as follows: ； The average back-side irradiance of the module is calculated by averaging or weighted averaging the back-side irradiance of all representative cells on the module, resulting in the module-level effective back-side irradiance used for subsequent electrical performance calculations. : ； in, The number of photovoltaic cells, The irradiance on the back of any single photovoltaic cell.

7. The method for calculating the irradiance of a bifacial photovoltaic module according to claim 2, characterized in that, In step 3, the total irradiance of the front side Direct component from the front Front scattering component and the frontal ground reflection component synthesis; The view factor of the frontal target area and the unobstructed ground unit consists of the following two parts. The first part is the non-shaded area directly below the front-row components of the target area. The formula is as follows: ； The second part consists of the frontal target area and the non-shaded area behind the shadow area. The formula is as follows: ； In the formula and This is a generic symbol that represents the designation of any row of components that has a reflective irradiance effect on the front of the current nth row. Ground received irradiance and viewing angle factor of the target area on the front of the component Depend on and Composition, namely: ; For S g For a ground surface with irradiance = 0, the relationship between the ground received irradiance and the viewing factor of the target area on the front of the component is calculated. The product of these components yields the frontal ground reflection component: ； in The total irradiance received by the ground. This refers to the ground reflectivity.

8. The method for calculating the irradiance of a bifacial photovoltaic module according to claim 7, characterized in that, Frontal radiation superposition: ； in The irradiance shielding coefficient for different support structures.

9. The method for calculating the irradiance of a bifacial photovoltaic module according to claim 6, characterized in that, The calculated frontal irradiance With back irradiance Combined, utilizing the dihedral factor Obtain the equivalent total irradiance The calculation formula is as follows: 。 10. A system for calculating the irradiance of a bifacial photovoltaic module employs the method described in any one of claims 1-9, characterized in that, include: The meteorological data input module is used to access DNI, DHI, and solar position information; The geometric modeling module is used to establish the array's two-dimensional geometric projection; The perspective factor calculation module is implemented based on the cross-line method. The occlusion detection module is used to perform light intersection detection between the support and the shadow; The irradiance synthesis module is used to output the equivalent total irradiance.

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