A design method and system for photovoltaic power generation systems suitable for polar regions

Abstract

This invention discloses a design method and system for a photovoltaic power generation system suitable for polar regions, comprising: generating an irradiance time series; setting a set of pitch angles for individual solar cell modules; setting a set of combined units, calculating the coupled average daily power curve of each combined unit at the current pitch angle, until the combined unit set is traversed; selecting the smallest combined unit; obtaining the smallest combined unit corresponding to each pitch angle; selecting the smallest combined unit with the largest coupled average daily power as the optimal combined unit; and topologically connecting multiple optimal combined units as needed to obtain a photovoltaic power generation system. This invention considers a minimum combined unit for convenient on-site installation in polar regions, while outputting a stable daily power curve. The designed photovoltaic power generation system has a smoother output and higher average power compared to general methods, reducing curtailment rate, increasing photovoltaic utilization, and reducing efficiency losses caused by inconsistencies.

Description

Technical Field

[0001] This invention relates to photovoltaic power generation technology, and in particular to a design method and system for photovoltaic power generation systems suitable for polar regions. Background Technology

[0002] Polar photovoltaic (PV) power generation systems refer to systems that utilize solar energy to generate electricity in polar regions. The extreme cold, strong winds, and polar days and nights of these regions place high demands on the design and operation of PV power generation systems. Polar PV power generation systems can provide clean, reliable, and sustainable energy for polar scientific research, exploration, and military activities, and also provide valuable data for polar environmental protection and climate change research. The main components of a polar PV power generation system include solar cell modules, support structures, controllers, inverters, batteries, and loads. Among these, the solar cell modules are the core components, and their performance and lifespan directly affect the efficiency and reliability of the entire system. The unique natural conditions of Antarctica present several challenges for constructing large-scale PV power generation systems, such as the low altitude of the sun and the existence of polar days and nights. Therefore, special design is required for the PV power generation system, which will directly affect the overall system's usability and power generation efficiency. Summary of the Invention

[0003] Purpose of the invention: The purpose of this invention is to provide a design method and system for photovoltaic power generation systems suitable for polar regions.

[0004] Technical solution: The present invention provides a design method for a photovoltaic power generation system suitable for polar regions, comprising the following steps:

[0005] S1. Create an irradiance data table for the area where the photovoltaic power generation system is to be installed, and generate an irradiance time series.

[0006] S2, Set the set of pitch angles for a single solar cell module;

[0007] S3. Based on the number of individual solar cell modules in each combined unit, set up a combined unit set, calculate the average daily power curve of the coupling of each combined unit at the current pitch angle, until the combined unit set has been traversed.

[0008] S4. Select the combination unit with the smallest variance of the coupled average daily power curve at the current pitch angle as the minimum combination unit;

[0009] S4. Traverse all pitch angles in the pitch angle set to obtain the minimum combined unit corresponding to each pitch angle; select the minimum combined unit with the largest coupled average daily power as the optimal combined unit.

[0010] S5. Connect multiple optimal combination units in a topology as needed to obtain a photovoltaic power generation system.

[0011] Furthermore, in step S1, an irradiance data table is created for the area where the photovoltaic power generation system will be installed, and an irradiance time series is generated, specifically as follows:

[0012] Irradiance data for the area where the photovoltaic power generation system will be installed is obtained from NASA irradiance data based on preset regional latitude, longitude, altitude, and sampling interval information and stored in a table; the irradiance data includes diffuse irradiance data and direct irradiance data;

[0013] Read data within a set start and end time range from the irradiance data table to generate an irradiance data time series.

[0014] Furthermore, in step S2, the pitch angle set is [0°-90°].

[0015] Furthermore, in step S3, each solar cell module in the combined unit has the same pitch angle.

[0016] Furthermore, in step S3, the coupled average daily power curve of each combined unit is calculated at the current pitch angle, specifically as follows:

[0017] The solar elevation angle and solar azimuth angle data are obtained as dependent variables. At the same time, the azimuth angle of the solar cell module, the elevation angle of the solar cell module, the height of the solar cell module above the ground, and the surface albedo are set to obtain the irradiance received by the surface of a single solar cell module.

[0018] The power generation of a single solar cell module is calculated based on the irradiance received on the surface of the module.

[0019] Based on the power generation curve of a single solar cell module, the coupled average daily power curve for each type of combined unit is calculated:

[0020] p_av=(p1+p2+…+p k ) / K

[0021] Where p_av represents the coupled average daily power curve of the combined unit, p1, p2, ..., p k These represent the average daily power curves of the solar cell modules at each azimuth angle in the combined unit, where K is the number of solar cell modules in the combined unit.

[0022] Furthermore, the specific calculation method for the irradiance received on the surface of a single solar cell module is as follows:

[0023] Based on the azimuth angle, elevation angle, height of the solar cell module above the ground, surface albedo, and direct and diffuse irradiance data read from the irradiance data table for the photovoltaic power generation area to be installed, the array plane irradiance received by the front and rear surfaces of a single solar cell module is calculated using the pvfactors model of the pvfactors_timeseries function. This yields the calculated irradiance values ​​received by the front and rear surfaces of a single solar cell module.

[0024] Furthermore, the specific calculation method for the power generation of a single solar cell module is as follows:

[0025] The temperature of the surface of a single solar cell module is calculated based on the irradiance received by the surface of the module, as well as ambient temperature and wind speed data.

[0026] Furthermore, the formula for calculating the DC power of a single solar cell module is as follows:

[0027]

[0028] Among them, P dc It is the DC power of a single solar cell module, G poaeff It is the irradiance received by the surface of a single solar cell module, P dc0 It is the DC rated power of a single solar cell module, γ pdc It is the temperature coefficient of a single solar cell module, T cell It is the surface temperature of a single solar cell module, T ref This is the standard test condition temperature.

[0029] Furthermore, when selecting single-glass solar cell modules, G poaeff It is the irradiance received by the front surface of a single solar cell module;

[0030] When selecting double-glass solar cell modules, G poaeff It is the sum of the irradiance received by the front surface and the irradiance received by the rear surface of a single solar cell module.

[0031] Furthermore, the method for topologically connecting multiple optimal combination units is as follows: each optimal combination unit faces the same side in the same string.

[0032] The present invention provides a photovoltaic power generation system design system suitable for polar regions, comprising:

[0033] The irradiance time series generation unit is used to create an irradiance data table for the area where a photovoltaic power generation system is to be installed, and to generate an irradiance time series.

[0034] Pitch angle set generation unit, used to set the pitch angle set of a single solar cell module;

[0035] The unit for calculating the average daily power curve of the combined unit is used to set up a set of combined units based on the number of individual solar cell modules in each combined unit, and calculate the average daily power curve of each type of combined unit at the current pitch angle until the entire set of combined units has been traversed.

[0036] The minimum combined unit determination unit is used to select the combined unit with the smallest variance of the coupled average daily power curve at the current pitch angle as the minimum combined unit;

[0037] The optimal combination unit is determined by traversing all pitch angles in the pitch angle set to obtain the minimum combination unit corresponding to each pitch angle; the minimum combination unit with the largest coupled average daily power is selected as the optimal combination unit.

[0038] A photovoltaic power generation system building unit is used to topologically connect multiple optimal combination units as needed to obtain a photovoltaic power generation system.

[0039] Beneficial effects: Compared with the prior art, the advantages of the present invention are:

[0040] (1) This invention realizes the entire process of photovoltaic power generation system design in polar regions through a special design method, providing a reference for the establishment of photovoltaic power stations in polar regions.

[0041] (2) The minimum combination scheme designed in this invention is more conducive to polar construction and transportation.

[0042] (3) The photovoltaic power generation system designed in this invention has a smoother output and a higher average power compared to the general method, which reduces the curtailment rate and increases the utilization rate of photovoltaics.

[0043] (4) The topology of the photovoltaic power generation system designed in this invention ensures the consistency of the same string and reduces the efficiency loss caused by inconsistency. Attached Figure Description

[0044] Figure 1 This is a flowchart of a photovoltaic power generation system design method according to an embodiment of the present invention;

[0045] Figure 2 This is the daily power curve of the smallest combined unit according to an embodiment of the present invention;

[0046] Figure 3 This is a photovoltaic power generation system topology according to an embodiment of the present invention. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of the present invention clearer, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Examples of these preferred embodiments are illustrated in the drawings. The embodiments of the present invention shown in and described with reference to the drawings are merely exemplary, and the present invention is not limited to these embodiments.

[0048] It should also be noted that, in order to avoid obscuring the invention with unnecessary details, only the structures and / or processing steps closely related to the solution according to the invention are shown in the accompanying drawings, while other details that are not closely related to the invention are omitted.

[0049] In view of the technical problems mentioned in the background, the present invention provides the following specific embodiments.

[0050] The present invention provides a design method for a photovoltaic power generation system applicable to polar regions. First, based on latitude and longitude information, the irradiance information of the area where the photovoltaic power generation system is to be installed is obtained, and the photovoltaic output power of a single solar cell module under different orientations and pitch angles is analyzed. Then, based on the photovoltaic output power of a single solar cell module, a minimum combined unit is considered to facilitate on-site installation in polar regions, while simultaneously outputting a stable daily power curve.

[0051] like Figure 1 As shown, the present invention provides a design method for a photovoltaic power generation system suitable for polar regions, which specifically includes the following steps:

[0052] S1. Create an irradiance data table for the area where the photovoltaic power generation system is to be installed, and generate an irradiance time series.

[0053] First, NASA irradiance data (including diffuse and direct irradiance data, with a sampling interval of 1 hour) is obtained based on the specific latitude, longitude, and altitude information of the area where the photovoltaic power generation system to be installed is located. A table is created using the DataFrame function, and meteorological data such as irradiance is stored in it. Irradiance data within the set start and end time range is read from the irradiance data table to generate an irradiance data time series.

[0054] S2. Set the pitch angle set for a single solar cell module [0°-90°];

[0055] S3. Based on the number of individual solar cell modules in each combined unit, set up a combined unit set, calculate the average daily power curve of the coupling of each combined unit at the current pitch angle, until the combined unit set has been traversed.

[0056] By acquiring solar altitude angle and solar azimuth angle data as dependent variables, and simultaneously setting the azimuth angle, altitude angle, height of the solar panel above the ground, and surface albedo, the irradiance received by a single solar panel surface is obtained. Based on the irradiance received by a single solar panel surface, the power generation of a single solar panel can be calculated through a series of functions. Specifically:

[0057] Based on the azimuth angle, elevation angle, height of the solar cell module above the ground, surface albedo, and direct and diffuse irradiance data read from the irradiance data table for the area where photovoltaic power generation is to be installed, the plane-of-array irradiance received by the front and rear surfaces of a single solar cell module is calculated using the pvfactors model of the pvfactors_timeseries function. This yields the calculated values ​​of the irradiance received by the front and rear surfaces of a single solar cell module.

[0058] The temperature of a solar cell module is calculated using the Faiman model with the temperature.faiman function. Based on the calculated irradiance received by the front and rear surfaces of a single solar cell module, as well as ambient temperature and wind speed data, the temperature of the surface of a single solar cell module is calculated using the temperature.faiman function.

[0059] The `pvsystem.pvwatts_dc` function is used to calculate the DC power of a solar panel. The formula for calculating the DC power of a single solar panel is:

[0060]

[0061] Among them, P dc It is the DC power of a single solar cell module, G poaeff It is the irradiance received by the surface of a single solar cell module, P dc0 It is the DC rated power on the nameplate, γ pdc It is the temperature coefficient (unit: 1 / C, typically -0.002 to -0.005 per degree Celsius), T cell It is the surface temperature of a single solar cell module, T ref This is the reference temperature (usually set to 25℃).

[0062] Based on the irradiance received by the front surface of a single solar cell module and the surface temperature of the single solar cell module calculated in the above steps, the DC power generation of the single solar cell module is calculated using the pvsystem.pvwatts_dc function.

[0063] If the solar cell module is a single-glass solar cell module, then the G in the above formula for calculating the DC power of a single solar cell module... poaeff G represents the irradiance received by the front surface of a single solar cell module. If the solar cell module is a double-glass solar cell module, then G in the above formula for calculating the DC power of a single solar cell module... poaeff It is the sum of the irradiance received on the front surface and the irradiance received on the rear surface of a single solar cell module.

[0064] Based on the power generation curve of a single solar cell module, the coupled average daily power curve for each type of combined unit is calculated:

[0065] p_av=(p1+p2+…+p k ) / K

[0066] Where p_av represents the coupled average daily power curve of the combined unit, p1, p2, ..., p k These represent the average daily power curves of the solar cell modules at each azimuth angle, and K is the number of solar cell modules in the combined unit.

[0067] The present invention provides a photovoltaic power generation system design system suitable for polar regions, comprising:

[0068] The irradiance time series generation unit is used to create an irradiance data table for the area where a photovoltaic power generation system is to be installed, and to generate an irradiance time series.

[0069] Pitch angle set generation unit, used to set the pitch angle set of a single solar cell module;

[0070] The unit for calculating the average daily power curve of the combined unit is used to set up a set of combined units based on the number of individual solar cell modules in each combined unit, and calculate the average daily power curve of each type of combined unit at the current pitch angle until the entire set of combined units has been traversed.

[0071] The minimum combined unit determination unit is used to select the combined unit with the smallest variance of the coupled average daily power curve at the current pitch angle as the minimum combined unit;

[0072] The optimal combination unit is determined by traversing all pitch angles in the pitch angle set to obtain the minimum combination unit corresponding to each pitch angle; the minimum combination unit with the largest coupled average daily power is selected as the optimal combination unit.

[0073] A photovoltaic power generation system building unit is used to topologically connect multiple optimal combination units as needed to obtain a photovoltaic power generation system.

[0074] Example:

[0075] Based on the set of pitch angles, the pitch angle of each individual solar cell module is set. Further, within the pitch angle set [0°-90°], the pitch angle of each individual solar cell module is set to b degrees to prepare for finding the optimal pitch angle. The pitch angle of each solar cell module in the combined unit is the same.

[0076] Set the number of solar cell modules in the current combined unit and determine the azimuth angle of each solar cell module. Further, based on the combination quantity set [1-K], set the number of solar cell modules in the combined unit and determine the azimuth angle of each solar cell module. K solar cell modules form a circle, meaning the azimuth angle of the kth module is α = 0 + 360 / K*k.

[0077] Calculate the coupled average daily power curve of all solar cell modules in the combined unit. Further, set the surface albedo parameter in the `pvfactors_timeseries` function. Because the surface of new and old snow differs, the albedo varies. The optimal albedo setting is 0.8, but in practice, it can be set to a value appropriate to the actual situation. Further, generate the irradiance time series `g` received by the panel at the corresponding solar location. Further, determine the type of solar cell module. The optimal solar cell module type is a double-glass solar cell module because the high albedo of Antarctic snow allows backsheet power generation to increase overall power output. However, in practice, any suitable solar cell module can be selected based on actual conditions. Further, set the inverter losses according to the selected inverter datasheet. The optimal inverter loss setting is 0.83, but in practice, any loss can be set to match the actual losses. Obtain the average daily power curves of k arrays with different orientations based on the photoelectric conversion efficiency of the double-glass photovoltaic panels (inverter function) and the generated irradiance sequence `g`, as shown below. Figure 2 The curves in the illustrated embodiment. p_av represents the average daily power curve of the combined unit, p1 to p k These represent the average daily power curves of the solar cell modules at each azimuth angle in the combined unit.

[0078] p_av=(p1+p2+…+p k ) / K

[0079] Variance determination of average daily power curve. Further, iterate through the set of combination quantities [1-8] for the variance and mean of average daily power, select the photovoltaic array with the smaller variance and the largest mean, and determine the minimum number of combination unit blocks k_min, such as... Figure 2 Curve 1 in the illustrated embodiment. Figure 2 The blue curve represents the average daily power curve for a minimum number of unit cells with 3 cells, the orange curve represents the average daily power curve for a minimum number of unit cells with 4 cells, the green curve represents the average daily power curve for a minimum number of unit cells with 5 cells, the red curve represents the average daily power curve for a minimum number of unit cells with 6 cells, the purple curve represents the average daily power curve for a minimum number of unit cells with 8 cells, and the brown curve represents the average daily power curve for a horizontally placed solar cell module, used for comparison.

[0080] Select the number of combined units with the smallest variance.

[0081] Iterate through all pitch angles. Further, record the current variance, the minimum combined unit pitch angle, and the number of solar cell modules. Iterate through the pitch angle set [0° - 90°] in 1-degree increments.

[0082] Determine the pitch angle with the maximum average daily power curve. Further, compare the number of solar cell modules and pitch angle combinations with the smallest daily average power variance in the pitch angle set, and obtain the smallest combined unit with the largest average power among those with the smallest final daily average power variance as the smallest component module of the final photovoltaic power generation system.

[0083] like Figure 3 The illustrated embodiment uses a minimum unit k_min = 3 and a pitch angle of 90 degrees as an example. The triangle in the diagram represents a minimum unit, where faces 11 and 12, facing the same direction, belong to the same group. 13 represents the spacing between two minimum units, which can be designed according to actual conditions; the optimal embodiment for the Kunlun Station area is 5 meters.

Claims

1. A design method for a photovoltaic power generation system suitable for polar regions, characterized in that, Includes the following steps: S1. Create an irradiance data table for the area where the photovoltaic power generation system is to be installed, and generate an irradiance time series. S2, Set the set of pitch angles for a single solar cell module; S3. Based on the number of individual solar cell modules in each combined unit, set up a combined unit set, calculate the average daily power curve of the coupling of each combined unit at the current pitch angle, until the combined unit set has been traversed. The coupling average daily power curve for each unit combination at the current pitch angle is calculated as follows: The solar elevation angle and solar azimuth angle data are obtained as dependent variables. At the same time, the azimuth angle of the solar cell module, the elevation angle of the solar cell module, the height of the solar cell module above the ground, and the surface albedo are set to obtain the irradiance received by the surface of a single solar cell module. The power generation of a single solar cell module is calculated based on the irradiance received on the surface of the module. Based on the power generation curve of a single solar cell module, the coupled average daily power curve for each type of combined unit is calculated: ， in, The average daily power curve representing the coupled unit. , ,..., These represent the average daily power curves of the solar cell modules at each azimuth angle in the combined unit. This refers to the number of solar cell modules in the combined unit; S4. Select the combination unit with the smallest variance of the coupled average daily power curve at the current pitch angle as the minimum combination unit; S4. Traverse all pitch angles in the pitch angle set to obtain the minimum combined unit corresponding to each pitch angle; select the minimum combined unit with the largest coupled average daily power as the optimal combined unit. S5. Connect multiple optimal combination units in a topology as needed to obtain a photovoltaic power generation system.

2. The design method for a photovoltaic power generation system suitable for polar regions according to claim 1, characterized in that, In step S1, an irradiance data table for the area where the photovoltaic power generation system will be installed is created, and an irradiance time series is generated, specifically as follows: Irradiance data for the area where the photovoltaic power generation system will be installed is obtained from NASA irradiance data based on preset regional latitude, longitude, altitude, and sampling interval information and stored in a table; irradiance data includes diffuse irradiance data and direct irradiance data; data within a set start and end time range is read from the irradiance data table to generate an irradiance data time series.

3. The design method for a photovoltaic power generation system suitable for polar regions according to claim 1, characterized in that, In step S2, the pitch angle set is [0°-90°].

4. The design method for a photovoltaic power generation system suitable for polar regions according to claim 1, characterized in that, In step S3, each solar cell module in the combined unit has the same pitch angle.

5. The design method for a photovoltaic power generation system suitable for polar regions according to claim 1, characterized in that, The specific method for calculating the irradiance received by the surface of a single solar cell module is as follows: Based on the azimuth angle, elevation angle, height of the solar cell module above the ground, surface albedo, and direct and diffuse irradiance data read from the irradiance data table for the photovoltaic power generation area to be installed, the array plane irradiance received by the front and rear surfaces of a single solar cell module is calculated using the pvfactors model of the pvfactors_timeseries function. This yields the calculated irradiance values ​​received by the front and rear surfaces of a single solar cell module.

6. The design method for a photovoltaic power generation system suitable for polar regions according to claim 1, characterized in that, The specific calculation method for the power generation of a single solar cell module is as follows: The temperature of the surface of a single solar cell module is calculated based on the irradiance received by the surface of the module, as well as ambient temperature and wind speed data. Furthermore, the formula for calculating the DC power of a single solar cell module is as follows: ， in, This is the DC power of a single solar cell module. It is the irradiance received by the surface of a single solar cell module. This is the DC rated power of a single solar cell module. It is the temperature coefficient of a single solar cell module. It is the surface temperature of a single solar cell module. This is the standard test condition temperature.

7. The design method for a photovoltaic power generation system suitable for polar regions according to claim 6, characterized in that, When selecting single-glass solar cell modules, It is the irradiance received by the front surface of a single solar cell module; When selecting double-glass solar cell modules, It is the sum of the irradiance received by the front surface and the irradiance received by the rear surface of a single solar cell module.

8. The design method for a photovoltaic power generation system suitable for polar regions according to claim 1, characterized in that, The method for topologically connecting multiple optimal combination units is as follows: each optimal combination unit faces the same side and is in the same string.

9. A design system for a photovoltaic power generation system suitable for polar regions, characterized in that, include: The irradiance time series generation unit is used to create an irradiance data table for the area where a photovoltaic power generation system is to be installed, and to generate an irradiance time series. Pitch angle set generation unit, used to set the pitch angle set of a single solar cell module; The unit for calculating the coupled average daily power curve of a combined unit is used to define a set of combined units based on the number of individual solar cell modules in each combined unit, and to calculate the coupled average daily power curve of each type of combined unit at the current pitch angle, until the entire set of combined units has been traversed. This includes: a coupled average daily power curve calculation unit, used to calculate the coupled average daily power curve of each type of combined unit at the current pitch angle, specifically: The solar elevation angle and solar azimuth angle data are obtained as dependent variables. At the same time, the azimuth angle of the solar cell module, the elevation angle of the solar cell module, the height of the solar cell module above the ground, and the surface albedo are set to obtain the irradiance received by the surface of a single solar cell module. The power generation of a single solar cell module is calculated based on the irradiance received on the surface of the module. Based on the power generation curve of a single solar cell module, the coupled average daily power curve for each type of combined unit is calculated: ， in, The average daily power curve representing the coupled unit. , ,..., These represent the average daily power curves of the solar cell modules at each azimuth angle in the combined unit. This refers to the number of solar cell modules in the combined unit; The minimum combined unit determination unit is used to select the combined unit with the smallest variance of the coupled average daily power curve at the current pitch angle as the minimum combined unit; The optimal combination unit is determined by traversing all pitch angles in the pitch angle set to obtain the minimum combination unit corresponding to each pitch angle; the minimum combination unit with the largest coupled average daily power is selected as the optimal combination unit. A photovoltaic power generation system building unit is used to topologically connect multiple optimal combination units as needed to obtain a photovoltaic power generation system.

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