Distributed photovoltaic-based string design method and device

Abstract

The invention relates to the technical field of solar photovoltaic power generation, and discloses a string design method and device based on distributed photovoltaic, and the method comprises the steps: setting assembly parameters, inverter parameters and slope parameters; generating all possible string combinations according to the component parameters, the inverter parameters and the slope parameters; screening out string combinations meeting electrical characteristic constraints and string design rules from all possible string combinations; optimizing the string combination meeting the screening condition according to a preset optimization logic; and sequencing the optimized string combination according to a preset string rule, and determining an optimal string mode. Manual calculation design is replaced by algorithm development and an automatic system, and the design period is shortened. Design rules are unified, scheme differences caused by manual subjectivity are eliminated, design efficiency and accuracy of the photovoltaic power station are improved, dependence on judgment and design of a manual supervisor is reduced, and therefore project cost and risks are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of solar photovoltaic power generation, and in particular to a distributed photovoltaic string design method and device. Background Art

[0002] With the rapid development of photovoltaic power generation technology, distributed photovoltaics have captured a significant market share in the PV industry. Residential distributed photovoltaics, a key application scenario, have long faced economic imbalances due to small installed capacity, high design precision requirements, and high equipment costs. String design, a key component of system performance, safety, and economics, not only improves power generation efficiency and reduces losses, but also reduces the number of devices, extends equipment life, simplifies operation and maintenance, and reduces equipment acquisition and long-term maintenance costs. However, due to the complex rooftop distribution in residential scenarios, string designs must be tailored to the orientations and inclinations of different arrays of photovoltaic modules. For economic reasons, these arrays must be connected to a single inverter with a limited number of MPPT inputs. Based on existing common design methods and specifications, even if a certain amount of power generation is sacrificed through string design, it is still cheaper than increasing equipment costs. However, this strategy has been widely adopted due to computational complexity and the lack of unified standards. Summary of the Invention

[0003] In view of this, the present invention provides a distributed photovoltaic string design method and device to solve the problems of high calculation difficulty and lack of unified standards in existing general design methods.

[0004] In a first aspect, the present invention provides a method for designing distributed photovoltaic strings, the method comprising:

[0005] Set component parameters, inverter parameters and slope parameters;

[0006] generating all possible string combinations according to the component parameters, the inverter parameters, and the slope parameters;

[0007] Filter out the string combinations that meet the electrical characteristic constraints and string design rules from all possible string combinations;

[0008] Optimize the string combinations that meet the screening conditions according to the preset optimization logic;

[0009] Sort the optimized string combinations according to the preset string grouping rules to determine the best string grouping method.

[0010] This paper provides a distributed photovoltaic string design method that replaces manual calculations and design with algorithm development and automated systems, shortening the design cycle. Unified design rules eliminate design variations caused by human subjectivity, improving the efficiency and accuracy of photovoltaic power station design, and reducing reliance on human judgment, thereby lowering project costs and risks.

[0011] In an optional embodiment, generating all possible string combinations according to the component parameters, the inverter parameters, and the slope parameters includes:

[0012] Generate an initial combination using a generative algorithm, wherein the initial combination satisfies a preset generation rule;

[0013] Using a lexicographical algorithm, the elements in the initial combination are gradually adjusted to generate all possible string combinations.

[0014] In an optional embodiment, selecting a string combination that meets electrical characteristic constraints and string design rules from all possible string combinations includes:

[0015] Calculate the difference between the maximum non-zero string and the minimum non-zero string in all string combinations, and select the string combination whose difference is not greater than the maximum high and low voltage difference of the string;

[0016] Calculate the difference between the maximum non-zero string and the minimum non-zero string in the same MPPT, and select the string combination whose difference is not greater than the maximum difference between the strings in the MPPT;

[0017] Obtain the input current of each MPPT and select the string combination whose input current is not greater than the preset input current;

[0018] The input power of each MPPT is obtained, and a string combination whose input power is not greater than a preset input power is selected.

[0019] In an optional embodiment, the string combinations that meet the screening conditions are optimized according to a preset optimization logic, including:

[0020] Traverse all string combinations that meet the screening conditions, perform summation on any string combinations in the string mode, filter out the string combinations that satisfy the sum of the strings equal to the number of main slope components, and put them into the first set;

[0021] Sum any combination of strings in the first set, assign the main slope attribute to the string combination whose sum is equal to the number of main slope components, assign the secondary slope attribute to the remaining string combinations, assign the mixed string attribute to any string with the secondary slope attribute, and put the string combination with the attribute into the second set.

[0022] In an optional embodiment, optimizing the string combinations that meet the screening conditions according to a preset optimization logic further includes:

[0023] Compare all string combinations in the second set, select the string combination with the smallest string size, and put it into the third set;

[0024] Comparing the number of 0s in all string combinations in the third set, and writing the string combination with the largest number of 0s into the fourth set;

[0025] Comparing the number of non-zero values ​​in all string combinations in the fourth set, and writing the string combination with the least number of non-zero values ​​into the fifth set;

[0026] Comparing all string combinations in the fifth set, selecting a string combination with the least string loops, and writing the string combination into the sixth set;

[0027] Comparing all string grouping methods in the sixth set, calculating the variance of the non-zero numbers in each MPPT in each string grouping method, and selecting the string grouping method with the smallest variance and writing it into the seventh set;

[0028] Compare all string grouping methods in the seventh set, count the number of 0s in the MPPT of the smallest string in each string grouping method, select the string grouping method with the largest number, and write it into the eighth set;

[0029] Compare all string grouping modes in the eighth set, calculate the variance between the number of non-zero numbers in each MPPT in each string grouping mode, select the string grouping mode with the smallest variance, and write it into the ninth set.

[0030] In an optional embodiment, the string combinations that meet the screening conditions are sorted according to the preset string grouping rules to determine the best string grouping method, including:

[0031] For each string mode in the ninth set, the strings in each MPPT are sorted from left to right in the order of primary, secondary, and mixed, and the sorted strings are recorded in the tenth set;

[0032] The mixed string components in the first string grouping method among all the string grouping methods in the tenth set are changed to a combination of the main slope components of the mixed string and the auxiliary slope components of the mixed string, and this combination method is determined as the optimal string grouping method. The number of mixed string components is equal to the sum of the number of main slope components of the mixed string and the number of auxiliary slope components of the mixed string.

[0033] In a second aspect, the present invention provides a distributed photovoltaic string design device, the device comprising:

[0034] Setting module, used to set component parameters, inverter parameters and slope parameters;

[0035] A generating module, configured to generate all possible string combinations according to the component parameters, the inverter parameters and the slope parameters;

[0036] A screening module is used to select string combinations that meet electrical characteristic constraints and string design rules from all possible string combinations;

[0037] Optimization module, used to optimize the string combination that meets the screening conditions according to the preset optimization logic;

[0038] The sorting module is used to sort the optimized string combinations according to the preset string grouping rules and determine the best string grouping method.

[0039] This invention provides a distributed photovoltaic string design device that replaces manual calculations and design through algorithm development and automated systems, shortening the design cycle. Unified design rules eliminate design variations caused by human subjectivity, improving the efficiency and accuracy of photovoltaic power station design, and reducing reliance on human judgment, thereby lowering project costs and risks.

[0040] In a third aspect, the present invention provides a computer device comprising: a memory and a processor, the memory and the processor being communicatively connected to each other, the memory storing computer instructions, and the processor executing the computer instructions to execute the distributed photovoltaic string design method according to the first aspect or any corresponding embodiment thereof.

[0041] In a fourth aspect, the present invention provides a computer-readable storage medium having computer instructions stored thereon, the computer instructions being used to enable a computer to execute the distributed photovoltaic string design method according to the first aspect or any corresponding embodiment thereof.

[0042] In a fifth aspect, the present invention provides a computer program product comprising computer instructions for causing a computer to execute the distributed photovoltaic string design method according to the first aspect or any corresponding embodiment thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0044] Figure 1 is a flow chart of a distributed photovoltaic string design method according to an embodiment of the present invention;

[0045] Figure 2 2. Schematic diagram of a string inverter connected to a photovoltaic power station according to an embodiment of the present invention;

[0046] Figure 3 2. It is a schematic diagram of a maximum power point tracking curve along with string voltage and current according to an embodiment of the present invention;

[0047] Figure 4 is a structural block diagram of a distributed photovoltaic string design device according to an embodiment of the present invention;

[0048] Figure 5 Schematic diagram of the hardware structure of a computer device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0049] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0050] Based on existing general PV string design methods and specifications, even if it is economically cheaper to sacrifice some power generation through string design than to increase equipment costs, the widespread promotion of this strategy faces the following problems due to the difficulty of calculation and the lack of unified standards:

[0051] 1. Complex business scenarios: Existing string design specifications and calculation methods cannot meet the calculation requirements when photovoltaic panels with different inclination angles and azimuth angles are connected to the same string, which affects business expansion.

[0052] 2. Low design efficiency: Conventional string group calculations and mixed string calculations are based on manual experience and calculations, which are labor-intensive and inefficient, making it difficult to quickly respond to complex scenario requirements.

[0053] 3. Insufficient standardization: Different designers have different understandings of constraints, resulting in the lack of unified design specifications.

[0054] 4. Simulation difficulties: Existing PV power station simulation software and tools, such as PVsyst, cannot directly simulate the relatively optimal solution after string grouping and string mixing, and cannot be used in household scenarios that pursue economic efficiency.

[0055] 5. Economic imbalance: Excessive pursuit of power generation efficiency leads to an increase in the number of inverters, or excessive losses lead to substandard economic performance.

[0056] To this end, this application needs to build an automatic calculation system through the application of innovative technologies to solve the problems of low design efficiency and inconsistent output solutions under the design model that relies on manual experience, as well as low system efficiency and high system costs due to unreasonable design.

[0057] According to an embodiment of the present invention, an embodiment of a distributed photovoltaic string design method is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0058] In this embodiment, a distributed photovoltaic string design method is provided, which can be used for the above-mentioned electronic terminals, such as computers, mobile phones, etc. Figure 1 is a flow chart of a distributed photovoltaic string design method according to an embodiment of the present invention. Figure 1 As shown, the process includes the following steps:

[0059] Step S1, setting component parameters, inverter parameters and slope parameters.

[0060] Specifically, initialize and set the following variable parameters: a) Component parameters: ① Component specifications ② Maximum difference between MPPT strings on the same path ③ Bluetooth operating range ④ Operating current ⑤ Operating temperature ⑥ Extremely high temperature ⑦ Extremely high temperature ⑧ Voltage temperature coefficient ⑨ Current temperature coefficient ⑩ Current temperature coefficient. b) Inverter parameters: ① Maximum connectable power ② Minimum connectable power ③ Maximum DC input voltage ④ Minimum DC input voltage ⑤ Maximum MPPT voltage ⑤ Minimum MPPT voltage ⑥ Maximum high and low voltage difference between strings. c) Slope parameters: ① Array orientation: Quantitatively set based on the east, south, west, or north slope and the building's orientation angle. ② Primary and secondary slope determination: Quantified based on the relationship between the array's east, south, west, or north slope and the building's orientation angle. Slope parameters also include: Slope information and number: specifically, including ① Slope orientation angle ② Slope orientation ③ Primary and secondary slope attributes ④ Number of components ④ Component inclination angle. After setting these parameters, collect building information and determine the building's slope type. Such as single slope, double slope, multi-slope, etc., according to different slope types, calculate slope parameters such as orientation angle, azimuth angle, number of components, component parameters, total number of strings, etc.

[0061] Among them, the string inverter has multiple input interfaces, each of which contains one positive and one negative, called a string loop. For example, a 50kW inverter usually has 8 or 10 inputs. The string inverter usually has a two-stage structure. The front stage is a voltage stabilization circuit, which is composed of a single or multiple string loops in parallel. Its main function is maximum power point tracking (MPPT) and stabilizing the DC bus voltage. The back stage is an inverter circuit, whose main function is to convert DC power into AC power. The inverter has an input parameter called the number of MPPT paths. Due to different technical routes of different manufacturers, one MPPT path is connected to 1, 2, 3 or more strings, and multiple input string loops are connected in parallel to form an MPPT loop. For a schematic diagram of the string inverter connected to a photovoltaic power station, see Figure 2 .

[0062] MPPT is the core technology in photovoltaic power generation systems. It refers to adjusting the output power of the photovoltaic array according to different external environmental characteristics such as ambient temperature and light intensity. Its core task is to adjust the working point of the inverter so that the photovoltaic string can output the maximum power. The output characteristics of photovoltaic modules are determined by the PV curve (power-voltage curve) and the IV curve (current-voltage curve). The maximum power point (MPPT) is located at the top of the PV curve. The string circuit of the inverter does not necessarily work alone, but the MPPT circuit works independently. Different MPPTs can connect modules of different brands and different powers, and the number of strings can also be different without affecting each other. For a schematic diagram of the maximum power point tracking curve with the string voltage and current, please refer to Figure 3 .

[0063] The impact of selecting MPPT circuits on system power generation: If the photovoltaic array includes multiple directions and multiple components, the more MPPTs, the better from the perspective of solving the mismatch problem; if the photovoltaic array has the same direction and components, the fewer MPPTs, the better from the perspective of stability and efficiency, because the more MPPTs, the higher the system cost, the worse the stability, and the greater the loss.

[0064] Step S2: Generate all possible string combinations based on component parameters, inverter parameters, and slope parameters.

[0065] Specifically, a generative algorithm is used to generate the initial combination, and then a lexicographic order is used to generate all possible combinations, aiming to improve the algorithm efficiency and generation quality and realize hierarchical data management.

[0066] Step S3 , selecting a string combination that meets electrical characteristic constraints and string design rules from all possible string combinations.

[0067] Specifically, before selecting string combinations, it is necessary to determine whether the generated string combinations are a non-empty set. If so, step S3 is executed to verify the validity of the combinations based on whether they meet the electrical characteristic constraints and string design rules, thereby selecting string combinations that meet the electrical characteristic constraints and string design rules. If not, the string design process ends immediately.

[0068] Furthermore, the string design rules are as follows: ① Whether the number of mixed strings meets the design requirements ② Different array components are connected to different MPPTs as much as possible ③ Mixed strings are connected to a single MPPT as much as possible ④ The number of components connected to each string is evenly distributed ⑤ Each string is evenly distributed with each MPPT ⑥ Output is sorted according to the array (inclination, azimuth) ⑦ The fewer mixed strings, the better ⑧ Definition of string rules, etc.

[0069] Specifically, the process of stringing PV modules needs to take into account electrical matching, shadow blocking, safety standards, and the actual environment. According to the national standard GB50797-2012 Photovoltaic Power Station Design Specification and revised version, in a PV array, the electrical performance parameters of each PV module in the same PV module string should be kept consistent, and the number of PV modules in series should be calculated according to the following formula.

[0070]

[0071] Where: K v K is the open circuit voltage temperature coefficient of the photovoltaic module; v ' is the working voltage temperature coefficient of the photovoltaic module; N is the number of photovoltaic modules in series (N is rounded up); t is the extreme low temperature under the working conditions of the photovoltaic module (℃); t' is the extreme high temperature under the working conditions of the photovoltaic module (℃); V dcmax is the maximum DC input voltage allowed by the inverter (V); V mpptma is the maximum value of the inverter MPPT voltage (V); V mpp1min is the minimum value of the inverter MPPT voltage (V); V oe is the open circuit voltage of the photovoltaic module (V); V pm is the operating voltage of the photovoltaic module (V). In actual application, there are many ways to string the components of the inverter. Assuming that there are i MPPTs, the i-th MPPT can connect j strings, and the maximum number of strings is N min ≤N i-j ≤N max or N i-j =0 Each string can be combined with any value within this range to select the dual-slope power station parameters that meet the conditions: the number of main slope components is recorded as N 主 , the number of auxiliary slope components is recorded as N 副 , the number of mixed strings is recorded as N 混 , initial value N 混0=0, the number of main slope components of the mixed string N 主混 Initial value N 主混0 = 0. In the embodiment of the present invention, the sum of all strings is defined as the sum of the components in the project: ∑N i-j =N 1-1 +N 1-2 +N 2-1 +N 2-2 +..+N n-2 .

[0072] The electrical characteristic constraints are as follows: ① The maximum and minimum number of strings must be met, allowing users to customize settings based on the power generation loss range. ② The non-zero high and low voltage difference between strings meets the inverter access requirements. ③ The high and low voltage difference between strings within the same MPPT channel meets the inverter access requirements. ④ The input current of each MPPT channel meets the inverter access requirements. ⑤ The input power of each MPPT channel meets the inverter access requirements.

[0073] Specific: (1) String power and current upper limit requirements

[0074] If the input current or power exceeds the range, the MPPT will not work properly, resulting in reduced efficiency. System safety: Input current or power exceeding the limit may cause the inverter to overheat, overload, or be damaged. Component matching: The string current and power within the same MPPT circuit should be as consistent as possible to avoid power loss. The inverter current and power limits are as follows:

[0075] I total ≤I mppt_max (1-3)

[0076] P total ≤P mppt_max (1-4)

[0077] Where, I total is the total current; P total is the total power; P mppt_max is the maximum input power of the inverter MPPT; I mppt_max is the maximum input current of the inverter MPPT.

[0078] (2) Requirements for differences in electrical parameters within the string

[0079] If the voltage differences between strings within the same MPPT circuit are too large, the MPPT cannot optimize the operating point of all strings simultaneously. Instead, the MPPT selects a compromise operating point, causing some strings to fail to operate at their maximum power point, thereby reducing system efficiency. Inverters typically have voltage and current input range protection mechanisms. Excessive string voltage differences may trigger these protection mechanisms, causing the inverter to shut down.

[0080] a) Voltage difference limitation: Assume that the voltage of string 1 is V1, the voltage of string 2 is V2, and V1≠V2. MPPT will select V mppt As the operating point, the total power loss of string 1 and string 2 is as follows. It is usually required that the voltage difference between strings in the same MPPT circuit does not exceed 5% or 10% (the specific value depends on the inverter model)

[0081] P loss1 =P max1 -P(V mppt ) (1-5)

[0082] P total_loss =P loss1 +P loss2 (1-6)

[0083]

[0084] Where, P loss1 、P loss2 is the power loss of string 1 and string 2; P total_loss is the power loss of the strings in the same MPPT; V1 and V2 are the string voltages in the same MPPT circuit; ΔV is the maximum high and low voltage difference of the string; P max1 is the maximum power of string 1; V mppt is the voltage when MPPT is at the maximum power point; P(V mppt ) is the power at V(mppt).

[0085] b) Current Difference Limitation: If the string currents differ significantly, the string with the lower current will limit the output current of the entire circuit, further increasing power losses. This difference value, ΔI, can be set manually.

[0086] Step S4: Optimize the string combinations that meet the screening conditions according to the preset optimization logic.

[0087] Specifically, multi-dimensional screening criteria are set, with power generation as the core indicator, while also considering factors such as string power matching, MPPT operating voltage range, and line losses. String combinations with similar power and high matching of current and voltage parameters are prioritized to ensure that strings connected to the same MPPT can operate within the optimal efficiency range, thereby improving MPPT efficiency.

[0088] Step S5: sorting the optimized string combinations according to the preset string grouping rules to determine the best string grouping method.

[0089] Specifically, possible strings are sorted according to pre-defined string grouping rules, and valid string combinations are output. For example, the strings within each MPPT can be sorted from left to right in the order of primary, secondary, and mixed.

[0090] This paper provides a distributed photovoltaic string design method that replaces manual calculations and design with algorithm development and automated systems, shortening the design cycle. Unified design rules eliminate design variations caused by human subjectivity, improving the efficiency and accuracy of photovoltaic power station design, and reducing reliance on human judgment, thereby lowering project costs and risks.

[0091] In an optional embodiment, step S2 includes:

[0092] Step S21: Generate an initial combination using a generative algorithm, where the initial combination satisfies a preset generation rule.

[0093] Specifically, in the generative algorithm, reducing the number of invalid combinations through combinatorial initialization is an optimization strategy that aims to improve algorithm efficiency and generation quality. In the generative algorithm, the use of combinatorial initialization can reduce invalid combinations, improve algorithm efficiency, and enhance generation quality. Implementation method: a) Use a generative algorithm to generate a set of initial combinations, and pre-generate a set of meaningful initial combinations based on a certain rule. These combinations can cover the key features of the problem space while avoiding invalid or redundant combinations. b) Define screening conditions, and define which combinations are valid based on the design principle of the string, such as whether the string rules, the maximum and minimum string differences are met; whether the physical characteristics, voltage, current, power and other restrictions are met. Filter combinations that meet the string c) Introduce the optimization mechanism of the fast averaging method in the generation process to further reduce the number of invalid combinations.

[0094] Step S22: Using a lexicographical algorithm, gradually adjust the elements in the initial combination to generate all possible string combinations.

[0095] Specifically, lexicographically generated combinations are an iterative generation method that gradually adjusts the elements in the combination to generate all possible combinations. For example, the combination is initialized to the minimum value (such as [1, 2, ..., k]). An element that can be increased is found, increased, and subsequent elements are adjusted to the increasing minimum value. This step is repeated until no new combinations can be generated.

[0096] Utilizing modular encapsulation, the overall string combination, single-channel MPPT string, and individual string are each encapsulated into a container object. This container object is used to encapsulate data from different levels of combinations and nests them as attributes of the previous level, meaning that one container object can serve as an attribute of another container object. This nested structure allows data to be organized in a hierarchical manner, making it easier to manage and operate. Each container type has insertion / extraction methods configured according to relevant rules for adding (storing) or removing (removing) data. These methods contain specific logic to ensure that only string combinations that meet the conditions enter the subsequent screening process.

[0097] In an optional embodiment, step S3 includes:

[0098] Step S31 , calculating the difference between the maximum non-zero string and the minimum non-zero string in all string combinations, and screening out string combinations whose difference is not greater than the maximum high and low voltage difference of the strings.

[0099] Specifically, the screening condition in this step is: (maximum non-zero string - minimum non-zero string) * extremely low temperature operating voltage of all strings ≤ maximum high and low voltage difference ΔV of the string.

[0100] The filter expression is as follows:

[0101] (N max -N min )*V pm_lowtem. ≤ΔV,N max ≠0, N min ≠0 (1-8)

[0102] Where N max is the maximum number of strings, N max =rounddown(MPPT voltage maximum V mpptmax / very low temperature operating voltage); N min is the minimum number of strings, N min =roundup(MPPT voltage minimum value V mpptmin / Extremely high temperature operating voltage; V pm_lowtem For the extremely low temperature working voltage, the extremely low temperature working voltage V pm_lowtem = Peak operating voltage V pm *[1+(extreme low temperature - 25)*voltage temperature coefficient / 100].

[0103] In addition, the open circuit voltage at very low temperature = open circuit voltage V oc *[1+(extreme low temperature - 25)*voltage temperature coefficient / 100], recorded as V oc_lowtem. Extremely high temperature open circuit voltage = open circuit voltage V oc *(1+(extreme high temperature - 25)*voltage temperature coefficient / 100), recorded as V oc_highttem . Extremely high temperature working voltage = peak working voltage V pm *(1+(extreme high temperature - 25)*voltage temperature coefficient / 100), recorded as V pm_highttem .

[0104] Step S32: Calculate the difference between the maximum non-zero string and the minimum non-zero string in the same MPPT, and select a string combination whose difference is not greater than the maximum difference between the strings in the MPPT.

[0105] Specifically, the screening condition in this step is: (largest non-zero string - smallest non-zero string) within the same MPPT line ≤ the maximum difference ΔN between strings within the MPPT.

[0106] The filter expression is as follows:

[0107] (N i,max -N i,min )≤ΔN (1-9)

[0108] Where N i,max is the largest non-zero string; N i,min is the minimum non-zero string; ΔN is the maximum difference between strings within the MPPT.

[0109] Step S33: obtaining the input current of each MPPT, and screening out the string combination whose input current is not greater than the preset input current.

[0110] Specifically, the screening conditions in this step are: MPPTX The input current is less than the maximum input current I MPPTX,max .

[0111] The filter expression is as follows:

[0112] I MPPTX ≤I MPPTX,max (2-0)

[0113] Where, I MPPTX MPPTX input current = number of connected strings Xi greater than 0 * peak operating current l pm ;I MPPTX,max is the maximum input current of MPPTX.

[0114] Step S34: obtaining the input power of each MPPT, and screening out the string combination whose input power is not greater than the preset input power.

[0115] Specifically, the screening conditions in this step are: MPPTXThe input power is less than or equal to the maximum input power P. MPPTX,max . Record the string grouping method (combination method) output by this step and enter it into the set R{}.

[0116] The filter expression is as follows:

[0117] P MPPTX ≤P MPPTX,max (2-1)

[0118] Where, P MPPTX P is the MPPTX input power, MPPTX input power = the sum of the number of MPPTX strings in each path * module specifications; MPPTX,max is the maximum input power of MPPTX.

[0119] Denoted as the set R{a1,a2,...,a n}.

[0120] In an optional embodiment, step S4 includes:

[0121] Step S41, traverse all string combinations that meet the screening conditions, perform summation on any string combinations in the string mode, screen out string combinations that meet the requirement that the sum of the strings is equal to the number of main slope components, and put them into the first set.

[0122] Specifically, traverse the set R{a1, a2, ..., a n}. Perform summation on any string in the string mode to determine whether the sum of the strings is equal to N 主坡 .

[0123] The expression is as follows:

[0124] if(a i +a j )=N 主坡 , where i≠j

[0125] Denoted as set T0{b1,b2,...,b n} (2-2)

[0126] Step S42, sum up any combination of strings in the first set, assign the main slope attribute to the string combination whose sum is equal to the number of main slope components, assign the secondary slope attribute to the remaining string combinations, assign the mixed string attribute to any string with the secondary slope attribute, and put the string combinations with the attribute into the second set.

[0127] Specifically, judge T0{b1, b2, ..., b n} is φ. When T0 is a non-empty set, traverse the set T0. Sum any combination of strings in the string method, and the sum is equal to N 主Assign the main slope attribute to the string group, and assign the secondary slope attribute to the remaining strings. Assign the mixed string attribute to any string group with the secondary slope attribute, and each secondary slope string group may be a mixed string group. All combinations are placed in the second set. By assigning the slope attribute to each string group, the optimal string grouping method can be subsequently selected.

[0128] The expression is as follows:

[0129] If T0{b1,b2,...,b n}≠φ

[0130] Traverse T0{} (2-3)

[0131] if(a i +a j )=N 主坡 , where i≠j (2-4)

[0132] Record the set T1{c1,c2,...,c n}

[0133] Define N 副坡 =N 混串 (2-5)

[0134] Step S43: compare all string combinations in the second set, select the string combination with the smallest string value, and put it into the third set.

[0135] Specifically, all string configurations within set T1{} are compared, and the ones with the lowest string (mixed) ratio are selected and written into set T2{}. Because mixed string connections between the main and secondary slopes result in significant power loss, it is desirable to connect as few components as possible. This screening step allows for the selection of as few components as possible.

[0136] The expression is as follows:

[0137] T2{d1,d2,...,d n}=min T1{c1,c2,...,c n} (2-6)

[0138] Step S44 , comparing the number of 0s in all string combinations in the third set, and writing the string combination with the largest number of 0s into the fourth set.

[0139] Specifically, compare the number of zeros in all string configurations within set T2{} and write the configuration with the most zeros into set T3{}. Record the string configuration output from this step and enter it into set T3{}. This screening step selects the configuration with the highest average value for each string, ensuring optimal power generation while freeing up more MPPT connections for optimal combination screening.

[0140] The expression is as follows:

[0141] T3{e1,e2,...,e n}=max{Countif T2{d1, d2,...,d n}=0} (2-7)

[0142] Step S45 , comparing the number of non-zero values ​​in all string combinations in the fourth set, and writing the string combination with the least number of non-zero values ​​into the fifth set.

[0143] Specifically, compare the number of non-zero strings in the MPPT where the string (mixed) is located in all string modes in set T3{}, and write the combination mode with the least number of non-zero strings into set T4{}; if N 主混 = 0, then T3{} = T4{}. Record the string grouping method output in this step and record it in the set T4{}. By executing this step, you can place the hybrid string into a separate MPPT channel as much as possible, or place as few non-hybrid strings as possible into the same MPPT channel to reduce its impact on other strings.

[0144] The expression is as follows:

[0145] T4{}=min{Countif T3{d1, d2,...,d n}≠0} (2-8)

[0146] When N 主混 =0, T4{f1, f2, ..., f n}=T3{d1,d2,...,d n} (2-9)

[0147] Step S46 , comparing all string combinations in the fifth set, selecting the string combination with the least string loops, and writing it into the sixth set.

[0148] Specifically, all string configurations within set T4{} are compared. When both (primary) and (secondary) strings exist in the MPPT, MPPTi-j = 1 for that path; otherwise, j = 0. The ij values ​​of each MPPT within each string configuration are summed, and this is used as the j for that string configuration. The string configuration with the smallest j is selected and written into set T5{}. Because the amount of radiation received by the main and secondary slope components varies at different times of the day, it is necessary to separate the main and secondary slope strings as much as possible and connect them to different MPPTs to ensure MPPT efficiency.

[0149] The expression is as follows:

[0150]

[0151] T5{g1,g2,...,g n}=min {α j} (3-1)

[0152] Step S47 , comparing all string modes in the sixth set, calculating the variance of the non-zero numbers in each MPPT in each string mode, and selecting the string mode with the smallest variance to write into the seventh set.

[0153] Specifically, all string configurations in set T5{} are compared, the variance of the non-zero values ​​within each MPPT path within each string configuration is calculated, and the string configuration with the smallest variance (evenly distributed) is selected and added to set T6{}. This step allows strings to be connected to as many MPPT paths as possible, reducing inter-string interference and improving MPPT efficiency.

[0154] The expression is as follows:

[0155] T6{h1,h2,...,h n}=min T5{D(g1),D(g2),...,D(g n )} (3-2)

[0156] Among them, D(g n ) represents g n The variance of .

[0157] Step S48, compare all string grouping modes in the seventh set, count the number of 0s in the MPPT where the smallest string in each string grouping mode is located, select the string grouping mode with the largest number, and write it into the eighth set.

[0158] Specifically, the number of 0s in the MPPT of the smallest string in each string mode is β. i , sum it up to get the β of the string mode i , filter out β i The maximum string configuration is written as set T7{}. Because the MPPT operating voltage is limited by the lower-voltage string, connect the smallest possible number of strings to a single MPPT, or connect as few strings as possible to the same MPPT, to improve MPPT efficiency.

[0159] The expression is as follows:

[0160]

[0161] T7{i1,i2,...,i n}=max{β i} (3-4)

[0162] Step S49: compare all string modes in the eighth set, calculate the variance between the number of non-zero values ​​in each MPPT in each string mode, select the string mode with the smallest variance, and write it into the ninth set.

[0163] Specifically, the variance of the number of non-zero values ​​within each MPPT path within each string configuration is calculated for all string configurations within set T7{}. The string configuration with the smallest variance (even distribution) is selected and stored in set T8{}. This step ensures that the number of strings within the MPPT path is as uniform as possible, minimizing the problem of reduced MPPT efficiency caused by inter-string power generation differences due to excessive strings connected to a single MPPT path.

[0164] The expression is as follows:

[0165] T8{j1,j2,...,j n}=min T7{D(i1), D(i2),...,D(i n )} (3-5)

[0166] Among them, D(i n ) means i n The variance of .

[0167] In an optional embodiment, step S5 includes:

[0168] Step S51 , sort the strings in each MPPT in each string mode in the ninth set from left to right in the order of primary-primary-secondary-mixed, and record the sorted strings in the tenth set.

[0169] Specifically, for each string configuration within set T8{}, the strings within each MPPT path are sorted from left to right in the order of primary, secondary, and mixed. The sorted strings are then entered into set T9{}. This sorting of strings by attribute is then used to identify the optimal string configuration.

[0170] The expression is as follows:

[0171] T9{k1,k2,...,k n}=Rank T8{j1,j2,...,j n} (3-6)

[0172] Step S52, changing the mixed string components in the first string grouping method among all the string grouping methods in the tenth set to a combination of the main slope components of the mixed string and the auxiliary slope components of the mixed string, and determining this combination method as the optimal string grouping method, and the number of mixed string components is equal to the sum of the number of main slope components of the mixed string and the number of auxiliary slope components of the mixed string.

[0173] Specifically, change the (mixed) in the first string mode of all string modes in the set T9{} to [main(N 主混 )+Pair(N 混 -N 主混 )], which is the best string mode for final output. By changing the mixed string output mode to the main and auxiliary ramp access mode, readability is improved. Example: 14 (main) + 0 / 14 (auxiliary + 0) / 14 (mixed), N 主混 =2, according to the string method, N 混 =14; calculate N 混 -N 主混 =12: After rewriting, the string formula is: 14 (primary) + 0 / 14 (secondary + 0) / 14 (primary 2 + secondary 12).

[0174] The main technical effects of the technical solution of this application include the following aspects:

[0175] 1. Social Benefits: This technology can improve the efficiency and accuracy of photovoltaic power plant design, reducing reliance on human judgment in design, thereby lowering project costs and risks, ensuring system power generation efficiency, and enhancing market competitiveness. Furthermore, this technology can contribute to environmental protection, promoting the development of renewable energy, reducing reliance on traditional energy sources, and thus reducing environmental pollution and energy consumption.

[0176] 2. Economic Benefits: Traditional manual design methods require significant time and technical expertise. However, this calculation method, combined with design software, can instantly calculate the optimal solution with a response time of 1-2 seconds, significantly improving design efficiency. It also maximizes the number of PV panels that can be connected to a single inverter, reducing the total number of inverters and project costs. Furthermore, this technology precisely controls power generation losses caused by string connections within an acceptable loss range, facilitating the operation and maintenance of PV power plants, reducing operating and maintenance costs, and ultimately improving economic benefits.

[0177] 3. Technical Benefits: This method leverages automated design software to design and optimize PV power plants with greater precision, efficiency, and intelligence, thereby improving plant efficiency and power generation. Therefore, this technology can enhance the design and technical content of PV power plants, driving the development and innovation of PV power plant technology.

[0178] This embodiment also provides a distributed photovoltaic string design device for implementing the aforementioned embodiments and preferred implementations. Details already described are omitted. As used below, the term "module" may refer to a combination of software and / or hardware that implements a predetermined function. While the devices described in the following embodiments are preferably implemented using software, implementation using hardware, or a combination of software and hardware, is also possible and contemplated.

[0179] This embodiment provides a distributed photovoltaic string design device, such as Figure 4 As shown, including:

[0180] The acquisition module 401 is used to acquire component parameters, inverter parameters and slope parameters.

[0181] The generation module 402 is used to generate all possible string combinations according to component parameters, inverter parameters and slope parameters.

[0182] The screening module 403 is configured to screen out, from all possible string combinations, string combinations that meet electrical characteristic constraints and string design rules.

[0183] The optimization module 404 is used to optimize the string combinations that meet the screening conditions according to the preset optimization logic.

[0184] The sorting module 405 is used to sort the optimized string combinations according to the preset string grouping rules to determine the best string grouping method.

[0185] The further functional description of each of the above modules and units is the same as that of the above corresponding embodiments and will not be repeated here.

[0186] The distributed photovoltaic string design device in this embodiment is presented in the form of a functional unit, where the unit refers to an ASIC (Application Specific Integrated Circuit) circuit, a processor and memory that executes one or more software or fixed programs, and / or other devices that can provide the above functions.

[0187] This invention provides a distributed photovoltaic string design device that replaces manual calculations and design through algorithm development and automated systems, shortening the design cycle. Unified design rules eliminate design variations caused by human subjectivity, improving the efficiency and accuracy of photovoltaic power station design, and reducing reliance on human judgment, thereby lowering project costs and risks.

[0188] The embodiment of the present invention also provides a computer device having the above Figure 4 The distributed photovoltaic string design device shown.

[0189] See also Figure 5 , Figure 5 is a structural diagram of a computer device provided by an optional embodiment of the present invention, such as Figure 5As shown, the computer device includes: one or more processors 10, memory 20, and interfaces for connecting various components, including high-speed interfaces and low-speed interfaces. Various components utilize different buses to communicate with each other and can be installed on a common mainboard or installed in other ways as needed. The processor can process the instructions executed in the computer device, including instructions stored in the memory or on the memory to display the graphical information of the GUI on an external input / output device (such as, a display device coupled to the interface). In some optional embodiments, if necessary, multiple processors and / or multiple buses can be used together with multiple memories and multiple memories. Equally, multiple computer devices can be connected, and each device provides part of the necessary operations (for example, as a server array, a group of blade servers, or a multi-processor system). Figure 5 A processor 10 is taken as an example.

[0190] The processor 10 may be a central processing unit, a network processor, or a combination thereof. The processor 10 may further include a hardware chip. The hardware chip may be an application-specific integrated circuit, a programmable logic device, or a combination thereof. The programmable logic device may be a complex programmable logic device, a field programmable gate array, a general purpose array logic, or any combination thereof.

[0191] The memory 20 stores instructions that can be executed by at least one processor 10, so that the at least one processor 10 executes the method shown in the above embodiment.

[0192] The memory 20 may include a program storage area and a data storage area, wherein the program storage area may store an operating system and application programs required for at least one function; the data storage area may store data created based on the use of the computer device, etc. In addition, the memory 20 may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some optional embodiments, the memory 20 may optionally include a memory remotely located relative to the processor 10, and these remote memories may be connected to the computer device via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0193] The memory 20 may include a volatile memory, such as a random access memory; the memory may also include a non-volatile memory, such as a flash memory, a hard disk or a solid-state drive; the memory 20 may also include a combination of the above types of memory.

[0194] The computer device further includes an input device 30 and an output device 40. The processor 10, the memory 20, the input device 30 and the output device 40 may be connected via a bus or other means. Figure 5 The bus connection is taken as an example.

[0195] The input device 30 can receive input digital or character information and generate key signal input related to user settings and function control of the computer device, such as a touch screen, a keypad, a mouse, a trackpad, a touch pad, an indicator stick, one or more mouse buttons, a trackball, a joystick, etc. The output device 40 can include a display device, an auxiliary lighting device (e.g., an LED), and a tactile feedback device (e.g., a vibration motor). The above-mentioned display device includes but is not limited to a liquid crystal display, a light emitting diode, a display, and a plasma display. In some optional embodiments, the display device can be a touch screen.

[0196] The embodiment of the present invention also provides a computer-readable storage medium. The above-mentioned method according to the embodiment of the present invention can be implemented in hardware, firmware, or implemented as a computer code that can be recorded in a storage medium, or implemented as a computer code that is originally stored in a remote storage medium or a non-temporary machine-readable storage medium and downloaded through a network and will be stored in a local storage medium, so that the method described herein can be stored in such software processing on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only storage memory, a random access memory, a flash memory, a hard disk or a solid-state drive, etc.; further, the storage medium can also include a combination of the above-mentioned types of memory. It can be understood that a computer, a processor, a microprocessor controller or programmable hardware includes a storage component that can store or receive software or computer code. When the software or computer code is accessed and executed by a computer, a processor or hardware, the method shown in the above embodiment is implemented.

[0197] A portion of the present invention may be applied as a computer program product, such as a computer program instruction, which, when executed by a computer, can call or provide the method and / or technical solution according to the present invention through the operation of the computer. Those skilled in the art should understand that the form in which the computer program instruction exists in a computer-readable medium includes, but is not limited to, a source file, an executable file, an installation package file, etc. Accordingly, the way in which the computer program instruction is executed by the computer includes, but is not limited to: the computer directly executes the instruction, or the computer compiles the instruction and then executes the corresponding compiled program, or the computer reads and executes the instruction, or the computer reads and installs the instruction and then executes the corresponding installed program. Here, the computer-readable medium may be any available computer-readable storage medium or communication medium that can be accessed by the computer.

[0198] This application first counts the orientation, inclination and installed capacity of each photovoltaic panel in the different arrays designed in the project, then combines and classifies photovoltaic panels with the same orientation and inclination, and selects the smallest inverter that can be connected based on the installed capacity and over-allocation ratio. Finally, the above information is input into the string calculation system proposed in this article. The system will automatically calculate the relatively optimal string solution based on the input parameters and provide a visual output result.

[0199] Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention. Such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A distributed photovoltaic string design method, characterized in that: The method comprises: Set component parameters, inverter parameters and slope parameters; generating all possible string combinations according to the component parameters, the inverter parameters, and the slope parameters; Filter out the string combinations that meet the electrical characteristic constraints and string design rules from all possible string combinations; Optimize the string combinations that meet the screening conditions according to the preset optimization logic; Sort the optimized string combinations according to the preset string grouping rules to determine the best string grouping method.

2. The distributed photovoltaic string design method according to claim 1, characterized in that: All possible string combinations are generated according to the component parameters, the inverter parameters, and the slope parameters, including: Generate an initial combination using a generative algorithm, wherein the initial combination satisfies a preset generation rule; Using a lexicographical algorithm, the elements in the initial combination are gradually adjusted to generate all possible string combinations.

3. The distributed photovoltaic string design method according to claim 1, characterized in that: Filter out the string combinations that meet the electrical characteristic constraints and string design rules from all possible string combinations, including: Calculate the difference between the maximum non-zero string and the minimum non-zero string in all string combinations, and select the string combination whose difference is not greater than the maximum high and low voltage difference of the string; Calculate the difference between the maximum non-zero string and the minimum non-zero string in the same MPPT, and select the string combination whose difference is not greater than the maximum difference between the strings in the MPPT; Obtain the input current of each MPPT and select the string combination whose input current is not greater than the preset input current; The input power of each MPPT is obtained, and a string combination whose input power is not greater than a preset input power is selected.

4. The distributed photovoltaic string design method according to claim 1, characterized in that: Optimize the string combinations that meet the screening conditions according to the preset optimization logic, including: Traverse all string combinations that meet the screening conditions, perform summation on any string combinations in the string mode, filter out the string combinations that satisfy the sum of the strings equal to the number of main slope components, and put them into the first set; Sum any combination of strings in the first set, assign the main slope attribute to the string combination whose sum is equal to the number of main slope components, assign the secondary slope attribute to the remaining string combinations, assign the mixed string attribute to any string with the secondary slope attribute, and put the string combination with the attribute into the second set.

5. The distributed photovoltaic string design method according to claim 4, characterized in that: Optimize the string combinations that meet the screening conditions according to the preset optimization logic, including: Compare all string combinations in the second set, select the string combination with the smallest string size, and put it into the third set; Comparing the number of 0s in all string combinations in the third set, and writing the string combination with the largest number of 0s into the fourth set; Comparing the number of non-zero values ​​in all string combinations in the fourth set, and writing the string combination with the least number of non-zero values ​​into the fifth set; Comparing all string combinations in the fifth set, selecting a string combination with the least string loops, and writing the string combination into the sixth set; Comparing all string grouping methods in the sixth set, calculating the variance of the non-zero numbers in each MPPT in each string grouping method, and selecting the string grouping method with the smallest variance and writing it into the seventh set; Compare all string grouping methods in the seventh set, count the number of 0s in the MPPT of the smallest string in each string grouping method, select the string grouping method with the largest number, and write it into the eighth set; Compare all string grouping modes in the eighth set, calculate the variance between the number of non-zero numbers in each MPPT in each string grouping mode, select the string grouping mode with the smallest variance, and write it into the ninth set.

6. The distributed photovoltaic string design method according to claim 5, characterized in that: Sort the string combinations that meet the screening conditions according to the preset string grouping rules and determine the best string grouping method, including: For each string mode in the ninth set, the strings in each MPPT are sorted from left to right in the order of primary, secondary, and mixed, and the sorted strings are recorded in the tenth set; The mixed string components in the first string grouping method among all the string grouping methods in the tenth set are changed to a combination of the main slope components of the mixed string and the auxiliary slope components of the mixed string, and this combination method is determined as the optimal string grouping method. The number of mixed string components is equal to the sum of the number of main slope components of the mixed string and the number of auxiliary slope components of the mixed string.

7. A distributed photovoltaic string design device, characterized in that: The device comprises: Setting module, used to set component parameters, inverter parameters and slope parameters; A generating module, configured to generate all possible string combinations according to the component parameters, the inverter parameters and the slope parameters; A screening module is used to select string combinations that meet electrical characteristic constraints and string design rules from all possible string combinations; Optimization module, used to optimize the string combination that meets the screening conditions according to the preset optimization logic; The sorting module is used to sort the optimized string combinations according to the preset string grouping rules and determine the best string grouping method.

8. A computer device, characterized in that: include: A memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the distributed photovoltaic string design method according to any one of claims 1 to 6 by executing the computer instructions.

9. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a computer to execute the distributed photovoltaic string design method according to any one of claims 1 to 6.

10. A computer program product, characterized in that The method comprises computer instructions for causing a computer to execute the distributed photovoltaic string design method according to any one of claims 1 to 6.

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