Method for extracting parameters of three-diode model of photovoltaic cell

Abstract

The invention discloses a method for extracting parameters of a three-diode model of a photovoltaic cell, and the method comprises the steps: building a three-diode equivalent circuit model of the photovoltaic cell, and determining a plurality of to-be-recognized parameters of the photovoltaic cell according to the three-diode equivalent circuit model; output current-voltage I-V curve data of the three-diode equivalent circuit model are obtained, and the curve data at least comprise three feature point data, namely open circuit point voltage, short circuit point current and voltage and current of the maximum power point; and solving the three-diode equivalent circuit model based on the obtained I-V curve data, and obtaining an optimal solution of the to-be-identified parameters. The whole parameter extraction step has no matrix inversion operation and no random search process, the calculation complexity is low, continuous automatic model monitoring can be realized, and a parameter feasible region does not need to be manually set.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic power generation technology, and in particular to a method for extracting parameters of a three-diode equivalent circuit model of a photovoltaic cell. Background Technology

[0002] With the development of photovoltaic technology, the energy conversion efficiency of monocrystalline silicon photovoltaic cells is gradually approaching the Shockley limit. However, during the operation of these high-efficiency silicon photovoltaic cells, in addition to radiative or indirect recombination, Auger recombination inevitably occurs, causing the equivalent ideality factor of the photovoltaic cell to be less than 1. Therefore, based on the traditional photovoltaic model, the influence of Auger recombination is further considered, and a three-diode equivalent circuit model is proposed, as shown in the attached figure. Figure 1 As shown, three diodes represent the effects of indirect recombination, radiative recombination, and Auger recombination, respectively, with corresponding ideality factors of [missing information]. =2, =1, =2 / 3. The current-voltage (IV) relationship of the three-diode model can be obtained using Kirchhoff's current law as follows:

[0003]

[0004] The model parameters include: For photocurrent, , , These are the reverse saturation currents of the three diodes, For series resistance, For bypass resistance; other constants include: q = 1.602 × 10 -19 C is the unit charge, k = 1.3806503 × 10 -23 J / K is Boltzmann's constant, and T is the cell temperature on the Kelvin scale. This refers to the number of individual solar cells connected in series within a photovoltaic module. For a single photovoltaic cell, =1. However, existing technologies present certain difficulties in extracting parameters from a three-diode model. For example, regarding matrix decomposition techniques, due to... and A difference of 3 times makes the matrix elements The value at the short circuit point is 10. 0 Order of magnitude, and The value at the open point is 10. 18 Significant differences in magnitude can cause singularities when inverting matrices. Similarly, in metaheuristic optimization algorithms, the huge difference in the exponent term (e) can lead to underfitting. Furthermore, metaheuristic optimization algorithms also suffer from high computational complexity and non-convergence. SUMMARY

[0005] The present application aims to at least partially solve the technical problems existing in the related art.

[0006] The present application aims to at least partially solve the technical problems existing in the related art.

[0007] To achieve the above-mentioned purpose, the present application provides a method for extracting parameters of a three-diode equivalent circuit model of a photovoltaic cell, comprising the following steps:

[0008] S1, establishing a three-diode equivalent circuit model of a photovoltaic cell, and determining a plurality of to-be-identified parameters of the photovoltaic cell according to the three-diode equivalent circuit model;

[0009] S2, obtaining output current-voltage I-V curve data of the three-diode equivalent circuit model, wherein the curve data comprises at least three characteristic point data, open-circuit point voltage , short-circuit point current , voltage and current of the maximum power point;

[0010] S3, solving the three-diode equivalent circuit model based on the obtained I-V curve data to obtain an optimal solution of the to-be-identified parameters.

[0011] Further preferred technical solutions of the present application are that the three-diode equivalent circuit model comprises three diodes, an ideal current source, a parallel resistor and a series resistor, wherein the ideal current source, the three diodes and the parallel resistor are connected in parallel with the series resistor.

[0012] As a preferred, the three-diode equivalent circuit model is represented as:

[0013]

[0014] wherein, is the output current, is the output voltage, is the photo-generated current, , , are the reverse saturation currents of the three diodes respectively, is the series resistor, is the parallel resistor; =2, =1, =2 / 3 are ideal factors of the three diodes respectively, q=1.602×10 -19C is the unit charge amount, k = 1.3806503 x 10 -23 J / K is the Boltzmann constant, T is the battery temperature in Kelvin, is the number of cells in series in the photovoltaic module.

[0015] As preferred, the to-be-identified parameters are series resistance , parallel resistance , photo-generated current and reverse saturation current of three diodes , , .

[0016] As preferred, step S3 solves the three-diode equivalent circuit model based on the obtained I-V curve data to obtain the optimal solution of the to-be-identified parameters, specifically: selecting series resistance and parallel resistance as the loop variables, obtaining the analytical expression of the to-be-identified parameters by using the data of three characteristic points, and then calculating the fitting error of the output current, selecting the set of parameters with the minimum fitting error as the optimal model parameters.

[0017] As preferred, step S3 is specifically:

[0018] S301, input I-V curve data;

[0019] S302, set the reciprocal of , , and The maximum number of loops is and , and calculate the maximum value and , , and the step size , ;

[0020] S303, set The initial loop count i = 0;

[0021] S304, set =i x ;

[0022] S305, set The initial loop count j = 0;

[0023] S306, set =j x , = 1 / ;

[0024] S307, according to , and short-circuit current Calculate photocurrent ;

[0025] S308. Calculate the reverse saturation current of the three diodes based on the photovoltaic cell's operating states at open circuit and maximum power point. , and ;

[0026] S309. Calculate the root mean square error (RMSE) of the output current based on the model parameters.

[0027] S310. Let j = j + 1, and repeat steps S306-S309 until... Greater than Filter out the model with the smallest RMSE and save the corresponding model parameters;

[0028] S311. Let i = i + 1, and repeat steps S304-S310 until... Greater than The minimum RMSE is selected, and the corresponding model parameters are output as the optimal parameter values.

[0029] Preferably, in step S302 and maximum value , and step size , The specific calculation formula is as follows:

[0030]

[0031] .

[0032] Preferably, the photogenerated current in step S307 The calculation formula is:

[0033] .

[0034] Preferably, the reverse saturation current of the three diodes is... , and The calculation formula is:

[0035]

[0036]

[0037]

[0038] Among them, A, B, , , As an intermediate variable, specifically:

[0039]

[0040]

[0041]

[0042]

[0043] .

[0044] Preferably, the root mean square error (RMSE) of the output current fitting in step S309 is calculated as follows:

[0045] when , and When any one of them is less than zero, the root mean square error (RMSE) of the fit is infinite.

[0046] when , and When all parameters are greater than zero, the current at the short-circuit point, maximum power point, and open-circuit point is calculated based on the current parameter values, and then the root mean square error (RMSE) of the output current is calculated.

[0047]

[0048] in, , and These represent the currents calculated based on the current parameter values ​​at the short-circuit point, maximum power point, and open-circuit point, respectively.

[0049] Beneficial effects: The entire parameter extraction process of this invention does not involve matrix inversion, and there are no problems such as matrix singularity or numerical overflow in the numerical calculation process; there is no random search process, the computational complexity is low, and there are no underfitting or non-convergence problems of metaheuristic algorithms; continuous automated model monitoring can be achieved without manually setting the feasible region of parameters. Attached Figure Description

[0050] Appendix Figure 1 This is the equivalent circuit model of a photovoltaic cell with three diodes.

[0051] Appendix Figure 2 This is a flowchart of the algorithm for extracting parameters from a photovoltaic three-diode model according to the present invention.

[0052] Appendix Figure 3 Example 1: Root Mean Square Error (RMSE) of Photovoltaic Cells as a Perspective of Parameters and The changes.

[0053] Appendix Figure 4 The data points of the IV curve measured in the photovoltaic cell experiment of Example 1 and the model fitting results are shown.

[0054] Appendix Figure 5 Example 2: Root Mean Square Error (RMSE) of Photovoltaic Module as a Perspective of Parameters and The changes.

[0055] Appendix Figure 6 The results show the IV feature points and model fitting results of the photovoltaic module experimental measurements in Example 2.

[0056] Appendix Figure 7 The results show the light and temperature conditions, IV feature points, and model parameter extraction results of the outdoor continuous test of the photovoltaic module in Example 3. Detailed Implementation

[0057] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, embodiments of this invention, and should not be construed as limiting the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. In the description of this invention, it should be understood that the terminology used is for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0058] The following is combined with Figures 1-7 The present invention describes a method for extracting parameters of a three-diode model of a photovoltaic cell, the specific steps of which are as follows:

[0059] S1. Establish a three-diode equivalent circuit model of the photovoltaic cell, and determine several parameters of the photovoltaic cell to be identified based on the three-diode equivalent circuit model;

[0060] The equivalent circuit model of three diodes includes: three diodes, an ideal current source, a parallel resistor, and a series resistor. The ideal current source, the three diodes, and the parallel resistor are connected in parallel and then connected in series with the series resistor.

[0061] The circuit model is represented as follows:

[0062]

[0063] in, For output current, For output voltage, For photocurrent, , , These are the reverse saturation currents of the three diodes, For series resistance, These are parallel resistors; =2, =1, =2 / 3 are the ideal factors for the three diodes respectively, q=1.602×10 -19 C is the unit charge, k = 1.3806503 × 10 -23 J / K is Boltzmann's constant, and T is the cell temperature on the Kelvin scale. This refers to the number of individual solar cells connected in series in a photovoltaic module.

[0064] The parameter to be identified is the series resistance. Parallel resistors Photocurrent and the reverse saturation current of the three diodes , , .

[0065] S2. Obtain the output current-voltage (IV) curve data of the three-diode equivalent circuit model. The curve data includes at least three characteristic point data points, including the open-circuit voltage. Short-circuit current Voltage at maximum power point and current ;

[0066] S3. Solve the equivalent circuit model of the three diodes based on the obtained IV curve data to obtain the optimal solution of the parameters to be identified. Specifically, select the series resistance and parallel resistance as loop variables, use the three feature point data to obtain the analytical expression of the parameters to be identified, then calculate the fitting error of the parameters to be identified, and select the set of parameters with the smallest fitting error as the optimal model parameters.

[0067] S301. Input IV curve data;

[0068] S302, Setting The reciprocal of is , and The maximum number of loops are respectively and and calculate and maximum value , and step size , The specific calculation formula is as follows:

[0069]

[0070] ;

[0071] S303, Settings Initial loop count i = 0;

[0072] S304, Settings =i× ;

[0073] S305, Settings The initial loop count j = 0;

[0074] S306, Settings =j× , = 1 / ;

[0075] S307, according to , and short-circuit current Calculate photocurrent :

[0076] ;

[0077] S308. Calculate the reverse saturation current of the three diodes based on the photovoltaic cell's operating states at open circuit and maximum power point. , and The specific calculation formula is as follows:

[0078]

[0079]

[0080]

[0081] Among them, A, B, , , As an intermediate variable, specifically:

[0082]

[0083]

[0084]

[0085]

[0086] ;

[0087] S309, Root mean square error (RMSE) of the fit of the output current calculated from the basic model parameters;

[0088] when , and When any one of them is less than zero, the root mean square error (RMSE) of the output current fitting is infinite.

[0089] when , and When all parameters are greater than zero, the current at the short-circuit point, maximum power point, and open-circuit point is calculated based on the current parameter values, and then the root mean square error (RMSE) of the output current is calculated.

[0090]

[0091] in, , and These are the currents calculated based on the current parameter values ​​at the short-circuit point, maximum power point, and open-circuit point, respectively.

[0092] S310. Let j = j + 1, and repeat steps S306-S309 until... Greater than Filter out the model with the smallest RMSE and save the corresponding model parameters;

[0093] S311. Let i = i + 1, and repeat steps S304-S310 until... Greater than The minimum RMSE is selected, and the corresponding model parameters are output as the optimal parameter values.

[0094] The specific steps of the present invention are described below with reference to specific embodiments:

[0095] Example 1: Parameters were extracted for the high-efficiency monocrystalline silicon HIT photovoltaic cell developed by LONGi Green Energy Technology Co., Ltd. The cell efficiency was 26.3%, and its IV curve was measured and certified by the Hamelin Solar Energy Research Institute (ISFH). The characteristic point data of the IV curve and the test conditions are shown in Table 1.

[0096] Table 1. Characteristic point data and test conditions of the IV curve of photovoltaic cell in Example 1

[0097]

[0098] like Figure 2 As shown, the specific steps for extracting the parameters of the three-diode model in Example 1 are as follows:

[0099] Step 1: Input IV curve data, including open-circuit point voltage. = 0.75 V, short-circuit current = 40.49 mA / cm 2 Maximum power point voltage =0.677 V and current = 38.85 mA / cm 2 .

[0100] Step 2, record The reciprocal of is (Right now = 1 / ),set up and Maximum number of loops =300 and =300, and calculate and The maximum value and step size are as follows:

[0101]

[0102]

[0103] Step 3, settings The initial value of the loop counter is i=0.

[0104] Step 4, settings =i× ,judge Is it greater than If yes, proceed to step 13; otherwise, proceed to step 5. Taking an initial value of i=0 as an example, the process will proceed to step 5. When the loop reaches i=301, it will jump to step 13.

[0105] Step 5, settings The initial value of the loop counter is j=0.

[0106] Step 6, Settings =j× ,judge Is it greater than If yes, proceed to step 12; otherwise, proceed to step 7. Taking an initial value of j=0 as an example... =0, less than After assessment, the next step will be step 7. When j=51, =0.4051 kΩ -1 still smaller than After assessment, the next step will be step 7. When j=301, =2.4306 kΩ -1 greater than After assessment, the next step will be to step 12.

[0107] Step 7, Calculate = 1 / And calculate based on the operating state of the photovoltaic cells under short circuit. During a short circuit (V=0, I= Since the diode is not turned on, the diode current can be ignored, thus obtaining the calculation. The method is as follows:

[0108]

[0109] Taking i=0 and j=0 as an example, =0, = +∞, = 40.49 mA / cm 2 Let's take i=100 and j=50 as an example again. =6.2844×10 -4 kΩ, =2.4686 kΩ, =40.5003 mA / cm 2 .

[0110] Step 8: Calculate based on the photovoltaic cell's operating states at open circuit and maximum power point. , , At the open circuit point of the photovoltaic cell (V= (I=0) and maximum power point (V= , I= Based on the IV relationship, two equations can be obtained. The power reaches its extreme value at the maximum power point, i.e., d(IV) / dV| V=Vmp =0, therefore we can obtain a total of 3 equations, and we can solve them using these 3 equations. , , For convenience, intermediate variables A and B are introduced. , , :

[0111]

[0112]

[0113]

[0114]

[0115]

[0116] Further calculations , , as follows:

[0117]

[0118]

[0119]

[0120] Taking i=0 and j=0 as an example, we calculate A=5.2626×10 5 B = 2.1782 × 10 6 , =1.6400 mA / cm 2 , =40.4900 mA / cm 2 , =1.4745 mA / cm 2 , =1.4065×10 -6 mA / cm 2 , = 1.7714×10 -12 mA / cm 2 , =2.8080×10 -18 mA / cm 2 Taking i=100 and j=50 as an example again, A=8.4630×10 5 B = 2.1782 × 10 6 , =1.3662 A, =40.1965 mA / cm2, =1.5193 mA / cm2, =5.1806×10 -6 mA / cm 2 , =–1.0763×10 -11 mA / cm 2 , =7.7386×10 -18 mA / cm 2 .

[0121] Step 9, based on model parameters , , , , , Calculate the root mean square error (RMSE) of the output current fitting. Determine... , , If all values ​​are greater than 0, set the root mean square error (RMSE) to infinity (+∞); otherwise, calculate the model currents at the short-circuit point, maximum power point, and open-circuit point based on the current parameter values ​​(denoted as ). , and ), and calculate the root mean square error (RMSE):

[0122]

[0123] Taking i=0, j=0 as an example, since , , All are greater than 0, resulting in RMSE = 2.4395. Taking i = 100 and j = 50 as another example, since... Since it is less than 0, we set RMSE to +∞.

[0124] Step 10: Determine if RMSE is minimized. If so, accept the current parameter value as the optimal parameter value; otherwise, no action is required.

[0125] Step 11: Set j = j + 1 and jump to step 6.

[0126] Step 12, set i = i + 1, and jump to step 4.

[0127] Step 13: End the loop and output the optimal parameter values.

[0128] Example 1: The RMSE (logarithm of Log10) of a photovoltaic cell varies with the cycle counts i and j (i.e., varies with the cycle counts i and j). and = The changes are shown in the attached document. Figure 3 As shown in the figure, the pure white area represents RMSE of +∞. By comparison, it was found that the RMSE is minimized when i=13 and j=0, and the optimal model parameters at this point are shown in Table 2. The fitting curves plotted based on the optimal model parameters are attached. Figure 4 As shown, the fitted curve matches the experimentally measured data points very well, verifying the feasibility of the present invention.

[0129] Table 2. Optimal values ​​of parameters for the three-diode model of photovoltaic cell in Example 1

[0130]

[0131] Example 2: Parameters were extracted for the double-sided glass n-type silicon photovoltaic module developed by SunEvo Solar. The module is named "EVO6N-750W" and consists of 66 cells connected in series. It has an efficiency of 24.1%. Its IV curve characteristic point data and test conditions are shown in Table 3.

[0132] Table 3. Characteristic point data and test conditions of the photovoltaic module IV curve in Example 2

[0133]

[0134] The specific steps for extracting the parameters of the three-diode model in Example 2 are as follows:

[0135] Step 1: Input the characteristic point data of the IV curve, including the open-circuit voltage. =50.77 V, short-circuit current =18.71 A, maximum power point voltage =42.68 V and current = 17.58 A.

[0136] Step 2, record The reciprocal of is (Right now = 1 / ),set up and Maximum number of loops =300 and =300, and calculate and The maximum value and step size are as follows:

[0137]

[0138]

[0139] Step 3, settings The initial value of the loop counter is i=0.

[0140] Step 4, settings =i×Δs, judge Is it greater than If yes, proceed to step 13; otherwise, proceed to step 5. Taking the initial value i=0 as an example, the system will proceed to step 5, while when the loop reaches i=301, it will jump to step 13.

[0141] Step 5, settings The initial value of the loop counter is j=0.

[0142] Step 6, Settings =j× ,judge Is it greater than If yes, proceed to step 12; otherwise, proceed to step 7. Taking an initial value of j=0 as an example... =0, less than Based on the judgment, the next step will be step 7. When j=51, =0.0044Ω -1 still smaller than Based on the judgment, the next step will be step 7, and when j=301, =0.0266Ω -1 greater than After assessment, the next step will be to step 12.

[0143] Step 7, Calculate = 1 / And calculate based on the operating state of the photovoltaic cells under short circuit. During a short circuit (V=0, I= Since the diode is not turned on, the diode current can be ignored, thus obtaining the calculation. The method is as follows:

[0144]

[0145] Taking i=0 and j=0 as an example, =0, = +∞, = 18.7100 A. Taking i=100 and j=50 as another example, =0.1539Ω, =0.0044Ω, =18.7227 A.

[0146] Step 8: Calculate based on the photovoltaic cell's operating states at open circuit and maximum power point. , , At the open circuit point of the photovoltaic cell (V= (I=0) and maximum power point (V= , I= Based on the IV relationship, two equations can be obtained. The power reaches its extreme value at the maximum power point, i.e., d(IV) / dV| V=Vmp =0, therefore we can obtain a total of 3 equations, and we can solve them using these 3 equations. , , For convenience, intermediate variables A and B are introduced. , , :

[0147]

[0148]

[0149]

[0150]

[0151]

[0152] Further calculations , , as follows:

[0153]

[0154]

[0155]

[0156] Taking i=0 and j=0 as an example, we calculate A=2.9165×10 5 B = 3.1675 × 10 6 , =1.1300 A (amperes), =18.7100 A, =0.6985 A, =2.8868×10 -6 A, = 3.6337×10 -12 A, =–8.4616×10 - 19 A. Taking i=100 and j=50 as an example again, A=6.4759×10 5 B = 3.1675 × 10 6 , =0.9418 A, =18.4980 A, =0.7383 A, =7.0584×10 -7 A, = 1.0363×10 -12 A, =1.8454×10 -19 A.

[0157] Step 9, based on model parameters , , , , , Calculate the root mean square error (RMSE) of the output current fitting. Determine... , , If all values ​​are greater than 0, set the root mean square error (RMSE) to infinity (+∞); otherwise, calculate the model currents at the short-circuit point, maximum power point, and open-circuit point based on the current parameter values ​​(denoted as ). , and ), and calculate the root mean square error (RMSE):

[0158]

[0159] Taking i=0, j=0 as an example, since Since it's less than 0, we set RMSE to +∞. Let's take i=100 and j=50 as another example. , , All values ​​are greater than 0, and the calculated RMSE is 6.8033E-07.

[0160] Step 10: Determine if RMSE is minimized. If so, accept the current parameter value as the optimal parameter value; otherwise, no action is required.

[0161] Step 11: Set j = j + 1 and jump to step 6.

[0162] Step 12, set i = i + 1, and jump to step 4.

[0163] Step 13: End the loop and output the optimal parameter values. Example 2: The RMSE (logarithm of Log10) of the photovoltaic module increases with the loop counts i and j (i.e., increases with the number of iterations). and = The changes are shown in the attached document. Figure 5 As shown in the figure, the pure white area represents RMSE of +∞. By comparison, we can see that the RMSE is minimized when i=147 and j=163, and the optimal model parameters at this point are shown in Table 4. The fitting curves plotted based on the optimal model parameters are attached. Figure 6 As shown, the fitted curve fits the three feature point data very well, further verifying the feasibility of the present invention.

[0164] Table 4. Optimal values ​​of parameters for the three-diode model of the photovoltaic module in Example 2

[0165]

[0166] Example 3: Parameter extraction for the "HIT05662-Golden" photovoltaic module developed by the National Renewable Energy Laboratory (NREL) in the United States. Solar irradiance, module temperature, and module open-circuit voltage were measured continuously for 5 days in an outdoor environment. Short-circuit current Maximum power point voltage and current like Figure 7 As shown, the daily measurement time is from 6:00 AM to 6:00 PM, with a set of data recorded every 15 minutes. Based on the method of the present invention, the parameters of the three-diode model of Example 3 are extracted from these two hundred+ sets of feature point data, and the results are as follows. Figure 7 As shown, the component has a series resistor. When the light intensity is greater than 300W / m 2 Under certain conditions, the photocurrent is basically stable. The trend of change is consistent with the light irradiance, while the reverse saturation current... , , The invention exhibits regular periodic fluctuations as light and temperature change, which conforms to the laws of semiconductor physics and verifies the reliability of the invention under complex testing conditions.

[0167] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for extracting parameters of a three-diode model of a photovoltaic cell, characterized in that, Includes the following steps: S1. Establish a three-diode equivalent circuit model of the photovoltaic cell, and determine several parameters of the photovoltaic cell to be identified based on the three-diode equivalent circuit model; S2. Obtain the output current-voltage (IV) curve data of the three-diode equivalent circuit model. The curve data includes at least three characteristic point data points, including the open-circuit voltage. Short-circuit current Voltage at maximum power point and current ; S3. Solve the equivalent circuit model of the three diodes based on the obtained IV curve data to obtain the optimal solution for the parameters to be identified.

2. The method for extracting parameters of a photovoltaic cell three-diode model according to claim 1, characterized in that, The equivalent circuit model of the three diodes includes: three diodes, an ideal current source, a parallel resistor, and a series resistor, wherein the ideal current source, the three diodes, and the parallel resistor are connected in parallel and then connected in series with the series resistor.

3. The method for extracting parameters of a photovoltaic cell three-diode model according to claim 2, characterized in that, The equivalent circuit model of the three diodes is represented as follows: ； in, For output current, For output voltage, For photocurrent, , , These are the reverse saturation currents of the three diodes, For series resistance, These are parallel resistors; =2, =1, =2 / 3 are the ideal factors for the three diodes respectively, q=1.602×10 -19 C is the unit charge, k = 1.3806503 × 10 -23 J / K is Boltzmann's constant, and T is the cell temperature on the Kelvin scale. This refers to the number of individual cells connected in series in a photovoltaic module.

4. The method for extracting parameters of a photovoltaic cell three-diode model according to claim 3, characterized in that, The parameter to be identified is the series resistance. Parallel resistors Photocurrent and the reverse saturation current of the three diodes , , .

5. The method for extracting parameters of a photovoltaic cell three-diode model according to claim 4, characterized in that, Step S3 solves the equivalent circuit model of the three diodes based on the acquired IV curve data to obtain the optimal solution for the parameters to be identified. Specifically, the series resistance and parallel resistance are selected as loop variables, the analytical expression of the parameters to be identified is obtained using the data of the three feature points, the fitting error of the output current is calculated, and the set of parameters with the smallest fitting error is selected as the optimal model parameters.

6. The method for extracting parameters of a photovoltaic cell three-diode model according to claim 5, characterized in that, Step S3 is as follows: S301. Input IV curve data; S302, Setting The reciprocal of is , and The maximum number of loops are respectively and and calculate and maximum value , and step size , ; S303, Settings Initial loop count i = 0; S304, Settings =i× ; S305, Settings The initial loop count j = 0; S306, Settings =j× , = 1 / ; S307, according to , and short-circuit current Calculate photocurrent ; S308. Calculate the reverse saturation current of the three diodes based on the photovoltaic cell's operating states at open circuit and maximum power point. , and ; S309. Calculate the root mean square error (RMSE) of the output current based on the model parameters. S310. Let j = j + 1, and repeat steps S306-S309 until... Greater than Filter out the model with the smallest RMSE and save the corresponding model parameters; S311. Let i = i + 1, and repeat steps S304-S310 until... Greater than The minimum RMSE is selected, and the corresponding model parameters are output as the optimal parameter values.

7. The method for extracting parameters of a photovoltaic cell three-diode model according to claim 6, characterized in that, In step S302 and maximum value , and step size , The specific calculation formula is as follows: ； 。 8. The method for extracting parameters of a photovoltaic cell three-diode model according to claim 7, characterized in that, Photogenerated current in step S307 The calculation formula is: 。 9. The method for extracting parameters of a photovoltaic cell three-diode model according to claim 8, characterized in that, Three diodes reverse saturation current , and The calculation formula is: ； ； ； Among them, A, B, , , As an intermediate variable, specifically: ； ； ； ； 。 10. The method for extracting parameters of a photovoltaic cell three-diode model according to claim 9, characterized in that, The root mean square error (RMSE) of the output current fitting in step S309 is calculated as follows: when , and When any one of them is less than zero, the root mean square error (RMSE) of the fit is infinite. when , and When all parameters are greater than zero, the current at the short-circuit point, maximum power point, and open-circuit point is calculated based on the current parameter values, and then the root mean square error (RMSE) of the output current is calculated. ； in, , and These represent the currents calculated based on the current parameter values ​​at the short-circuit point, maximum power point, and open-circuit point, respectively.

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