A double-sided photovoltaic module multi-peak parameter calculation method based on a double-diode model

Abstract

This invention belongs to the field of photovoltaic power generation technology, proposing a method for calculating multi-peak parameters of bifacial photovoltaic modules based on a dual-diode model. This method is based on the equivalent circuit of a solar cell with dual diodes, establishes a multi-peak output characteristic model of bifacial photovoltaics using Kirchhoff's current law, introduces the Lambert-W function to simplify the equations, and considers the voltage superposition characteristics of normal and shaded cells to construct a string output model. Addressing the multi-peak nonlinear characteristics of the module output under shading conditions, in... I-V Selection of curve "positive + negative" and "positive + positive" intervals A 1 to H The photogenerated current is obtained by solving a system of simultaneous equations using first-order characteristic data points. I ph Diode reverse saturation current I o1 / I o2 Diode ideality factor n 1 / n 2. Series resistor R s and parallel resistors R sh There are seven parameters in total. This method not only improves the power generation efficiency and reliability of photovoltaic systems, but also provides quantitative theoretical support for engineering applications such as intelligent operation and maintenance and fault diagnosis. It has significant engineering value and industrial significance for promoting the development of the photovoltaic industry towards higher efficiency and intelligence.

Description

Technical Field

[0001] This invention belongs to the field of photovoltaic power generation technology and relates to a method for calculating multi-peak parameters of bifacial photovoltaic systems based on a dual-diode model. Background Technology

[0002] In recent years, against the backdrop of a growing global awareness of energy transition and sustainable development, domestic interest in photovoltaic power generation, a new energy sector with enormous potential, has continued to rise. Numerous enterprises, research institutions, and investors have keenly recognized the broad development prospects of photovoltaic power generation and have increased their investment in this field, attracting a continuous influx of massive research and development funds.

[0003] Bifacial photovoltaic (PV) modules, as an innovative and efficient photovoltaic power generation device, have demonstrated unique advantages in the field of solar energy utilization. Their core working principle lies in the fact that, like traditional PV modules, they not only directly receive sunlight from the front and convert it into electricity, but also cleverly utilize the characteristic of receiving reflected light from the back of the module, achieving increased power generation. In practical applications, reflected light from the ground, building surfaces, or other objects can be effectively captured and utilized by the back of the bifacial PV module, significantly improving overall power generation efficiency and providing strong support for the large-scale application of photovoltaic power generation and increased energy output. However, the output characteristics of bifacial PV modules are not static but are influenced by a variety of complex factors, exhibiting obvious multi-peak nonlinear characteristics. The unevenness of light distribution is one of the key factors affecting its output characteristics. In real-world environments, due to terrain undulations, building obstructions, uneven cloud distribution, etc., the intensity and angle of sunlight hitting the bifacial PV module will vary, resulting in different amounts of light received by different parts of the module. Temperature gradients are also significant. Photovoltaic modules generate heat during operation, and the temperature of different parts of the module may vary due to factors such as heat dissipation conditions and light intensity, thus affecting its electrical performance. In addition, shading conditions also have a significant impact on the output characteristics of bifacial photovoltaic modules. When part of the module is shaded by shadows, dust, or other objects, the current output of the shaded area will be suppressed, while the unshaded area can still generate electricity normally. This local shading will cause complex changes in the overall current-voltage (IV) characteristics of the module, and consequently, the module parameters will also change.

[0004] This invention provides a method for calculating multi-peak parameters of bifacial photovoltaic systems based on a dual-diode model. It calculates photovoltaic module parameters (photocurrent IT) using the module's output characteristic data. ph Diode reverse saturation current I o1, I o2 Diode ideality factors n1, n2, and series resistance R s Parallel resistor Rsh This method not only improves the power generation efficiency and reliability of photovoltaic systems, but also provides a theoretical basis for engineering applications such as intelligent operation and maintenance and fault diagnosis, which is of great significance for promoting the development of the photovoltaic industry towards high efficiency and intelligence. Summary of the Invention

[0005] The purpose of this invention is to provide a method for calculating multi-peak parameters of bifacial photovoltaic modules based on a dual-diode model. The specific steps are as follows:

[0006] Step 1: Based on the dual-diode equivalent circuit of the solar cell, establish a multi-peak output characteristic model of bifacial photovoltaic.

[0007] Step 2: To address the multi-peak output characteristics under occlusion conditions, a multi-peak parameter calculation method is proposed to calculate the model parameters corresponding to each peak.

[0008] Step 3: Based on the model parameters of each peak before the k-th peak, substitute the voltage of the separated data points into the relevant equations to calculate the model parameters corresponding to the k-th peak.

[0009] The multi-peak output characteristic model of bifacial photovoltaic in step one is established as follows:

[0010] (a) According to Kirchhoff's current law, the forward / reverse output characteristics of a solar cell can be obtained:

[0011]

[0012]

[0013] Where: I—solar cell output current, A; U—solar cell output voltage, V; n1, n2—diode ideality factor; V th —Thermal voltage of solar cell, V; U br — Diode reverse breakdown voltage, V.

[0014] (ii) By introducing the Lambert W function, while taking into account R sh and I ph I o1 I o2 We can obtain:

[0015]

[0016] In the formula: U cell_f —Solar cell forward output voltage, V; U cell_r —Reverse output voltage of solar cell, V;

[0017] (III) Output voltage U of the photovoltaic unit unit As a linear superposition of the output voltages of its internal batteries, according to equation (3), we can obtain:

[0018]

[0019] Where: m — number of normal batteries; —Number of batteries obstructed; —The forward output voltage of the shaded battery, in V; — Reverse output voltage of the shaded battery, V.

[0020] (iv) Analyzing the IV curve of a two-unit photovoltaic module in a bimodal state, the output characteristic model of the bifacial photovoltaic string is as follows:

[0021]

[0022] In the formula: i — the i-th unit; k — the k-th peak.

[0023] Step 2: Multi-peak separation based on the output characteristic model of bifacial photovoltaic modules

[0024] Each unit contains M solar cells. From equation (3), we can see that the output voltage U of the unit cells when they are all working normally is... unit·n .

[0025]

[0026] (v) As can be seen from equation (6), when the first peak contains m1 normal batteries, When the battery is blocked by a sheet, the output voltage of the module is U module , can be obtained :

[0027]

[0028] (vi) In the "forward + reverse" interval of the first peak (i.e., I) ph_1 >I module > >I turn1 Take three data points A1(U) a_1 ,I a_1 ), B1(U b_1 ,I b_1 ) and C1(U c_1 ,I c_1 Substituting A1 into equation (10), we get:

[0029]

[0030] Similarly, we can obtain ΔU b_1 , ΔU c_1 ,but , and for:

[0031]

[0032] (vii) To obtain more parameter information for the solar cells, the short-circuit current point (0, I) will be used. sc ), Open circuit voltage point (U) oc Substituting ,0) into equations (1) and (2), we get:

[0033]

[0034] (viii) Simplify equation (10)

[0035] Simplification principle: ,but

[0036] ,but

[0037] at the same time

[0038] We can obtain:

[0039]

[0040] (ix) In the "positive + positive" interval (i.e., I) ph_1 > >I module >I turn_1 Take five data points D1(U) d_1 ,I d_1 ), E1(U e_1 ,I e_1 ), F1(U f_1 ,I f_1 ), G1(U g_1 ,I g_1 ) and H1(U h_1 ,I h_1 )like Figure 3 Point D1(U) d_1 ,I d_1 Substituting the data into equation (1) and then into equation (10) and simplifying, we get:

[0041]

[0042] (x) Substitute equation (11) into equation (12) to eliminate I o1 ,remember for ,remember for ,remember for We can obtain:

[0043]

[0044] (xi) Taking the first derivative of the total differential of equation (1), we get:

[0045]

[0046] From equation (15), we can know that R s With any point (U) on the curve * ,I * ) dU / dI (i.e.) The relationship between ) and, combined with equation (121), eliminate I. o1 get:

[0047]

[0048] (xii) Substitute equation (15) into equation (14) to eliminate R. s And by R sh R sho We can obtain:

[0049]

[0050] In the formula: ——Eliminate R s After ; ——Eliminate R s After ;R sho —At the point of short-circuit current dU / dI.

[0051] (xiii) Take point E(U) on the IV curve e_1 ,I e_1 Similarly, we can obtain:

[0052]

[0053] (XIV) To solve for the values ​​of n1 and n2, another equation is needed, so a point F(U) can be taken on the IV curve. f_1 ,I f_1 From this, we can obtain:

[0054]

[0055] (XV) Since the voltage at the data point is the sum of the voltages of the normal battery and the shielded battery, the data point... The output voltage of the battery with the sheet shielding can be expressed as equation (19):

[0056]

[0057] (xvi) Based on the above, the remaining characteristic parameters of the shielded battery can be calculated using equation (20):

[0058]

[0059] In the formula: —Data point D1 corresponds to The sheet blocks the battery output voltage, V; —Equivalent resistance of the battery at point G1, in Ω. , , and Similarly, we can obtain the following.

[0060] Based on the above analytical formula for the seven parameters of photovoltaic modules, the required data points are as follows:

[0061] ② Short-circuit current point (0, I sc Open circuit voltage point (U) oc ,0)

[0062] ② Short-circuit current point (0, I sc The attachment point (δU,I) sc +δI), where δU is the minimum step size of the modulation voltage value of the voltage modulation module; any point (U*, I*), this point can be close to U oc In practice, I* can be taken as 0.2I. sc ; and the attachment point (δU+ U*,δI+ I*) of (U*,I*), where δU is the minimum step size of the modulation voltage value of the voltage modulation module;

[0063] ①A1 point (U a_1 ,I a_1 The current I at that point a_1 Can approach I sc In reality, Ia_1 0.8 I can be taken. sc ;

[0064] ②B1 point (U b_1 ,I b_1 This point should maintain a certain distance from point A. In reality, I... b_1 0.6 I can be taken sc ;

[0065] ③C1 point (U c_1 ,I c_1 This point cannot be close to points A and B. (In reality, I) c_1 0.4 I can be taken. sc ;

[0066] ④D1 point (U d_1 ,I d_1 This point is located on the second peak, and can actually be taken as 0.3 I. sc ;

[0067] ⑤E1 point (U e_1 ,I e_1 This point is a characteristic point in the middle of the rapid current decay segment, and can be taken as 0.25 I. sc ;

[0068] ⑥F1 point (U f_1 ,I f_1 This point can actually be taken as 0.2 I. sc ;

[0069] ⑦G1 point (U g_1 ,I g_1 This point is higher than I. turn1 However, there is still a difference, which can actually be taken as 0.1 I. sc ;

[0070] ⑧H1 point (U h_1 ,I h_1 This point is close to point G1, so it can be taken. δI is a small positive value

[0071] (xvii) Combining the model parameters of a normal battery with the first k The model parameters of the 1-peak shaded battery can be used to isolate the output voltage U of the k-th peak. module_k As shown in equation (21). According to the method for calculating the first peak parameter, the characteristic parameters of the kth peak can be obtained by substituting the voltage of the separated data points into equations (8), (9), (20), and (21):

[0072] Attached Figure Description

[0073] Figure 1 Flowchart of the multi-peak parameter calculation method for bifacial photovoltaic modules according to an exemplary embodiment of this specification;

[0074] Figure 2 Equivalent circuit diagram of a photovoltaic module model described in an exemplary embodiment of this specification;

[0075] Figure 3 This specification includes an exemplary embodiment of a point-sampling plot for calculating model parameters using IV curves;

[0076] Figure 4 This specification provides an example bimodal curve; Detailed Implementation

[0077] This invention provides a method for calculating multi-peak parameters of bifacial photovoltaic modules using analytical methods. Further explanation is provided to clarify the objectives, technical solutions, and effects of this invention. The specific examples described in this invention are for illustrative purposes only and are not intended to limit the invention.

[0078] The invention will be further described below with reference to the accompanying drawings. The calculation process for multi-peak parameters of a bifacial photovoltaic module is as follows: Figure 1 As shown, the specific steps include:

[0079] Step 1: Based on the dual-diode equivalent circuit of the solar cell, establish a multi-peak output characteristic model of bifacial photovoltaic.

[0080] (I) Based on the equivalent circuit model of the solar cell module, Kirchhoff's current law is used to obtain the forward / reverse output characteristic equations of the photovoltaic cell. The equivalent circuit model of the bifacial photovoltaic module is as follows: Figure 2 As shown. The output characteristic model is as follows:

[0081]

[0082]

[0083] Among them I ph For photocurrent, I R I is the current flowing through the parallel resistor. o1 with I o2 The diode's reverse saturation current is given by n1 and n2, which are the diode's ideality factors. R s For series resistance, R sh Let I be the parallel resistor, U be the output current of the photovoltaic cell, q be the electron charge, k be the Boltzmann constant, and T be the temperature of the photovoltaic cell. In the following text, ... .

[0084] (ii) By introducing the Lambert W function, while taking into account R sh R s and I ph I o1 I o2 Equations (1) and (2) can be expressed as:

[0085]

[0086] In the formula: U cell_f —Solar cell forward output voltage, V; U cell_r —Reverse output voltage of solar cell, V;

[0087] (III) Output voltage U of the photovoltaic unit unit It is a linear superposition of the output voltages of its internal batteries. When all batteries are in normal condition, the normal batteries exhibit positive output characteristics; when some batteries in the photovoltaic unit are shaded, their output current I... unit Greater than the photocurrent generated by the blocking When the battery is shaded, it exhibits reverse output characteristics; when the unit output current I... unit Less than the photocurrent generated by the blocking When the photovoltaic cell is shaded, it exhibits positive output characteristics. The photovoltaic unit output characteristic model is as follows:

[0088]

[0089] (iv) Taking a two-unit photovoltaic module as an example, when the units are shaded to varying degrees, the module's output characteristics can exhibit single-peak or multi-peak behavior. Analyzing the IV curve of this bimodal state, there are three possible states. In the first peak: when I... ph >I module >I turn1 At that time, all batteries in Unit 1 are operating normally, exhibiting positive output characteristics; in the second peak: when I turn1 >I module When I is blocked, the battery in unit 2 exhibits reverse output characteristics; turn1 > >I module At that time, the shaded cells in Unit 2 exhibit positive output characteristics. The output characteristic model of the bifacial photovoltaic module is as follows:

[0090]

[0091]

[0092]

[0093]

[0094]

[0095] By comprehensively analyzing equations (5) to (7) above, we can obtain the output characteristic model of the bifacial photovoltaic string:

[0096]

[0097]

[0098] Step Two: Based on the component output characteristic model, it is known that there is a superposition between its internal characteristics and external output form. Therefore, multi-peak separation is proposed to calculate the characteristic parameters of the multi-peak state of the bifacial photovoltaic module. In the multi-peak output characteristic curve of the photovoltaic string, a module composed of X two-unit modules will have a maximum of 2X peaks. Identify potential peak intervals and select 8 data points within each interval, as shown below. Figure 3 As shown. A bimodal curve. Figure 4 For example, the characteristic parameters of "Unit 1" are calculated using the 8 data points of the first peak; then, combined with the parameters of the first peak, the output voltage of the 8 data points of the second peak under the same current is calculated, the double peak is separated into a single peak, and the characteristic parameters of "Unit 2" are calculated.

[0099] (v) When a cell is shaded in the module and the shading state of each cell is the same, its IV characteristic curve also exhibits a single-peak state. Based on the single-peak parameter calculation method, a single-peak parameter calculation method applicable to the shading state is proposed. Taking a two-cell module as an example, each cell contains M solar cells. From equation (3), it can be seen that the output voltage U when all cells in the cell are working normally is... unit·n :

[0100]

[0101] (vi) As can be seen from equation (6), when the first peak contains m1 normal cells, When the battery is blocked by a sheet, the output voltage of the module is U module We can obtain ΔU:

[0102]

[0103] (vii) Equation (11) is about , , A three-variable linear equation. In the "positive + negative" interval of the first peak (i.e., I... ph_1 >I module > >I turn1 Take three data points A1(U) a_1 ,I a_1 ), B1(U b_1 ,I b_1 ) and C1(U c_1 ,I c_1 Substituting A1 into equation (11), we get:

[0104]

[0105] Similarly, we can obtain , .

[0106] (8) , and for:

[0107]

[0108] (ix) Taking the first derivative of the total differential of equation (1), we get:

[0109]

[0110] By finding a common denominator and simplifying equation (14), equation (14) can be transformed into:

[0111]

[0112] (x) To obtain more parameter information for solar cells, the short-circuit current point... Substituting into equations (1) and (15), we get:

[0113]

[0114]

[0115] In equation (17) At the point of short-circuit current ,and The value can be calculated from equation (18). In the calculation, samples need to be taken near the short-circuit current point. point.

[0116]

[0117] Then open circuit voltage point Substituting into equation (1), we get:

[0118]

[0119] (xi) Equations (16) and (19) can eliminate We get the following formula:

[0120]

[0121] (xii) Simplify equation (20)

[0122] Simplification principle: ,but

[0123] ,but

[0124] We can obtain:

[0125]

[0126] (xiii) Usually yes of The relationship between the two can be approximated by equation (21). For ease of calculation, the following text will use... Rewritten .

[0127]

[0128] Eliminating by combining equation (21) and equation (22) ,get:

[0129]

[0130] Equation (23) eliminates one of the seven parameters. This reflects the reverse saturation current of the diode. Diode ideality factor The relationship with output characteristics, i.e. .

[0131] (xiv) From equation (15), we can see that With any point place The relationship, and We can obtain:

[0132]

[0133] Equation (24) eliminates one of the seven parameters. This reflects the series resistance Diode reverse saturation current Diode ideality factor The relationship with output characteristics, i.e. In equation (20), The value can be calculated using equation (21):

[0134]

[0135] (XV) In the "positive + positive" interval (i.e., I) ph_1 > >I module >I turn1 Take five data points D1(U) d_1 ,I d_1 ), E1(U e_1 ,I e_1 ), F1(U f_1 ,I f_1 ), G1(U g_1 ,I g_1 ) and H1(U h_1 ,I h_1 Since the voltage at each data point is the sum of the voltages of the normal battery and the shielded battery, the data points... The output voltage of the battery with the sheet shielding is:

[0136]

[0137] (xvi) Take point D1(U) on curve IV. d_1 ,I d_1 Substituting into equation (1), we get:

[0138]

[0139] Substituting equation (27) into equation (16) and eliminating ,get:

[0140]

[0141] Simplifying equation (28), we have ,but ,get:

[0142]

[0143] Equation (29) eliminates one of the seven parameters. This reflects the reverse saturation current of the diode. Diode ideality factor Series resistor The relationship with output characteristics, i.e. .

[0144] (17) Formula (23) Substitution formula (29) In the middle, eliminate ,get:

[0145]

[0146] Eliminate I o1 ,remember for ,remember for ,remember for We can obtain: Equation (30) can be simplified to:

[0147]

[0148] (18) The value on the right side of equation (31) is a constant. To solve this problem, a point E(U) can be taken on the IV curve. e_1 ,I e_1 Then, according to steps (sixteen) and (seventeen), we obtain:

[0149]

[0150] From equations (31) and (32), we can obtain:

[0151]

[0152] (19) Eliminate I according to equations (23) and (24) o1 We can obtain:

[0153]

[0154] Equation (34) is the series resistance R s The expression for the diode ideality factors n1, n2, i.e., R s=l(u,i;n1,n2). Will R s Substituting =l(u,i;n1,n2) into... and In the middle, eliminate R s They are then recorded as follows: and So far, only the unknown parameters n1 and n2 are included.

[0155] (20) R s Substituting =l(u,i;n1,n2) into equation (33) eliminates R. s This yields an equation containing only unknowns n1 and n2:

[0156]

[0157] Equation (35) is denoted as equation ①.

[0158] (21) To solve for the values ​​of n1 and n2, another equation is needed, so a point F(U) can be taken on the IV curve. f_1 ,I f_1 According to steps (sixteen) and (seventeen), we can obtain:

[0159]

[0160] Then, by following steps (sixteen), (seventeen), and (eighteen), we can obtain the second equation:

[0161]

[0162] Equation (37) is denoted as equation ②.

[0163] (22) By combining equation ① and equation ②, the values ​​of n1 and n2 can be solved.

[0164] (23) Using equations (22) and (23) Find the reverse saturation current of the diode. :

[0165]

[0166]

[0167] (24) Using formula (24) Find the series resistance :

[0168]

[0169] In conclusion:

[0170]

[0171] In the formula: —Data point D1 corresponds to The sheet blocks the battery output voltage, V; —Equivalent resistance of the battery at point G1, in Ω. , , and Similarly, we can obtain the following.

[0172] The remaining five characteristic parameters of the shielded battery can be calculated using equation (41).

[0173] Based on the above analytical formula for the seven parameters of photovoltaic modules, the required data points (such as...) Figure 3 As shown below:

[0174] ①A1 point (U a_1 ,I a_1 The current I at that point a_1 Can approach I sc In reality, I a_1 0.8 I can be taken. sc ;

[0175] ②B1 point (U b_1 ,I b_1 This point should maintain a certain distance from point A. In reality, I... b_1 0.6 I can be taken sc ;

[0176] ③C1 point (U c_1 ,I c_1 This point cannot be close to points A and B. (In reality, I) c_1 0.4 I can be taken. sc ;

[0177] ④D1 point (U d_1 ,I d_1 This point is located on the second peak, and can actually be taken as 0.3 I. sc ;

[0178] ⑤E1 point (U e_1 ,I e_1 This point is a characteristic point in the middle of the rapid current decay segment, and can be taken as 0.25 I. sc ;

[0179] ⑥F1 point (U f_1 ,I f_1 This point can actually be taken as 0.2 I.sc ;

[0180] ⑦G1 point (U g_1 ,I g_1 This point is higher than I. turn1 However, there is still a difference, which can actually be taken as 0.1 I. sc ;

[0181] ⑧H1 point (U h_1 ,I h_1 This point is close to point G1, so it can be taken. δI is a small positive value

[0182] Step 3: Using a bimodal curve ( Figure 4 Taking this as an example, combining the model parameters of a normal battery with the first k... The model parameters of the 1-peak shaded battery can be used to isolate the output voltage U of the k-th peak. module_k As shown in equation (42). According to the method for calculating the first peak parameter, the characteristic parameters of the kth peak can be obtained by substituting the voltage of the separated data points into equations (12), (13), (26), and (41).

[0183]

[0184] The above provides specific implementation methods for engineering applications, but the present invention is not limited to the described implementation methods. The basic principle and method of the present invention are based on the above basic scheme. Changes, modifications, substitutions, and variations in the implementation methods without departing from the principle and spirit of the present invention still fall within the protection scope of the present invention.

Claims

1. A method for calculating multi-peak parameters of bifacial photovoltaic modules based on a dual-diode model, characterized in that: Based on the dual-diode equivalent circuit of a solar cell, a multi-peak output characteristic model of bifacial photovoltaics is established. Multi-peak separation is then performed, and a single-peak parameter calculation method suitable for shading conditions is proposed. Using the first-peak parameter calculation method, the separated data points are substituted into relevant equations to calculate the parameters of the k-th peak. These characteristic parameters include (photocurrent Ik). ph Diode reverse saturation current I o1 I o2 Diode ideality factors n1, n2, and series resistance R s Parallel resistor R sh Where k is a positive integer, k≥1, and when k≥2, the first k-1 peaks refer to the first to (k-1)th peaks that have been calculated. The specific steps are as follows: Step 1: Based on the dual-diode equivalent circuit of the solar cell, establish a multi-peak output characteristic model of bifacial photovoltaic. Step 2: Perform multi-peak separation based on the component output characteristic model, and obtain a single-peak parameter calculation method applicable to the occlusion state based on the single-peak parameter calculation method. Step 3: Using the first peak parameter calculation method, substitute the voltage of the separated data points into the relevant equations to calculate the characteristic parameters of the kth peak.

2. According to the method described in claim 1, the bifacial photovoltaic multi-peak output characteristic model in step one is established as follows: (I) Based on Kirchhoff's current law, establish the forward / reverse output characteristic equations of the solar cell: Where: I—solar cell output current, A; U—solar cell output voltage, V; n1, n2—diode ideality factor; V th —Thermal voltage of solar cell, V; U br — Diode reverse breakdown voltage, V. (ii) By introducing the Lambert W function, while taking into account R sh and I ph I o1 I o2 We can obtain: In the formula: U cell_f —Solar cell forward output voltage, V; U cell_r —Reverse output voltage of solar cell, V; in (III) Output voltage U of the photovoltaic unit unit As a linear superposition of the output voltages of its internal batteries, according to equation (3), we can obtain: Where: m — number of normal batteries; —Number of batteries obstructed; —The forward output voltage of the shaded battery, in V; — Reverse output voltage of the shaded battery, V. (iv) Analyzing the IV curve of a two-unit photovoltaic module in a bimodal state, the output characteristic model of the bifacial photovoltaic string is as follows: In the formula: i — the i-th unit; k — the k-th peak.

3. According to claim 1, the method for calculating the single-peak parameter in step two is as follows: Each unit contains M solar cells. From equation (3), we can see that the output voltage U of the unit cells when they are all working normally is... unit·n . (v) As can be seen from equation (6), when the first peak contains m1 normal batteries, When the battery is blocked by a sheet, the output voltage of the module is U module , can be obtained : (vi) In the "forward + reverse" interval of the first peak (i.e., I) ph_1 >I module > >I turn1 Take three data points A1(U) a_1 ,I a_1 ), B1(U b_1 ,I b_1 ) and C1(U c_1 ,I c_1 Substituting A1 into equation (10), we get: Similarly, we can obtain ΔU b_1 ΔU c_1 ,but , and for: (vii) To obtain more parameter information for the solar cells, the short-circuit current point (0, I) will be used. sc ), Open circuit voltage point (U) oc Substituting ,0) into equations (1) and (2), we get: (viii) Simplify equation (10) Simplification principle: ,but ,but at the same time We can obtain: (ix) In the "positive + positive" interval (i.e., I) ph_1 > >I module >I turn_1 Take five data points D1(U) d_1 ,I d_1 ), E1(U e_1 ,I e_1 ), F1(U f_1 ,I f_1 ), G1(U g_1 ,I g_1 ) and H1(U h_1 ,I h_1 As shown in Figure 3. Place point D1(U) d_1 ,I d_1 Substituting the data into equation (1) and then into equation (10) and simplifying, we get: (x) Substitute equation (11) into equation (12) to eliminate I o1 ,remember for ,remember for ,remember for We can obtain: (xi) Taking the first derivative of the total differential of equation (1), we get: From equation (15), we can see that R s With any point (U) on the curve * ,I * ) dU / dI (i.e.) The relationship between ) and, combined with equation (121), eliminate I. o1 get: (xii) Substitute equation (15) into equation (14) to eliminate R. s And by R sh R sho We can obtain: In the formula: ——Eliminate R s After ; ——Eliminate R s After ;R sho —At the point of short-circuit current dU / dI. The derivative is obtained through numerical calculation using adjacent sampled data points. (xiii) Take point E(U) on the IV curve e_1 ,I e_1 Similarly, we can obtain: (XIV) To solve for the values ​​of n1 and n2, another equation is needed, so a point F(U) can be taken on the IV curve. f_1 ,I f_1 From this, we can obtain: (XV) Since the voltage at the data point is the sum of the voltages of the normal battery and the shielded battery, the data point... The output voltage of the battery with the sheet shielding can be expressed as follows: (xvi) Based on the above, the remaining characteristic parameters of the shielded battery can be calculated using equation (20): In the formula: —Data point D1 corresponds to The sheet blocks the battery output voltage, V; —Equivalent resistance of the battery at point G1, in Ω. , , and Similarly, we can obtain the following.

4. According to the analytical expression of the feature parameters in claim 3, the required data points are as follows: ①A1 point (U a_1 ,I a_1 The current I at that point a_1 Can approach I sc In reality, I a_1 0.8 I can be taken. sc ; ②B1 point (U b_1 ,I b_1 This point should maintain a certain distance from point A. In reality, I... b_1 0.6 I can be taken sc ; ③C1 point (U c_1 ,I c_1 This point cannot be close to points A and B. (In reality, I) c_1 0.4 I can be taken. sc ; ④D1 point (U d_1 ,I d_1 This point is located on the second peak, and can actually be taken as 0.3 I. sc ; ⑤E1 point (U e_1 ,I e_1 This point is a characteristic point in the middle of the rapid current decay segment, and can be taken as 0.25 I. sc ; ⑥F1 point (U f_1 ,I f_1 This point can actually be taken as 0.2 I. sc ; ⑦G1 point (U g_1 ,I g_1 This point is higher than I. turn1 However, there is still a difference, which can actually be taken as 0.1 I. sc ; ⑧H1 point (U h_1 ,I h_1 This point is close to point G1, so it can be taken. δI is a small positive value.

5. Combining the method described in claim 1 or 3, and combining the model parameters of a normal battery with the calculated first k... The model parameters of the 1-peak shaded battery can be used to isolate the output voltage U of the k-th peak. module_k As shown in equation (21). According to the method for calculating the first peak parameter, the characteristic parameters of the kth peak can be obtained by substituting the voltage of the separated data points into equations (8), (9), (20), and (21): 。

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