Maximum power point tracking method, photovoltaic system, storage medium and program product

Abstract

The embodiment of the invention discloses a maximum power point tracking method, a photovoltaic system, a storage medium and a program product. The method comprises the steps that a first current and voltage curve obtained through forward scanning of a photovoltaic module and a second current and voltage curve obtained through reverse scanning of the photovoltaic module are obtained; determining a plurality of voltage intervals based on the first current-voltage curve and the second current-voltage curve; determining key parameters of a maximum power point tracking algorithm corresponding to each voltage interval; the key parameters at least comprise one or more of disturbance compensation, a power threshold value and waiting duration; the waiting time length is the waiting time length for acquiring power after the photovoltaic module is disturbed; and determining the maximum output power of the photovoltaic module based on the key parameters corresponding to each voltage interval and a maximum power point tracking algorithm.

Description

TECHNICAL FIELD

[0001] The present application relates to, but is not limited to, the technical field of photovoltaic technology, and particularly relates to a maximum power point tracking method, a photovoltaic system, a storage medium and a program product. BACKGROUND

[0002] In the related art, the tracking scheme of the maximum power point tracking (MPPT) algorithm is mainly adapted to crystalline silicon components, and the hysteresis effect of photovoltaic components is not considered. Therefore, when the existing maximum power point tracking algorithm is used to track the photovoltaic components with the hysteresis effect, the accuracy of the tracked optimal power point is poor, and even the optimal power point cannot be tracked. SUMMARY

[0003] Therefore, the embodiments of the present application provide at least a maximum power point tracking method, a photovoltaic system, a storage medium and a program product.

[0004] The technical scheme of the embodiments of the present application is implemented as follows:

[0005] On the one hand, the embodiments of the present application provide a maximum power point tracking method, which comprises: obtaining a first current-voltage curve of a photovoltaic component obtained through forward scanning and a second current-voltage curve obtained through reverse scanning; determining a plurality of voltage intervals based on the first current-voltage curve and the second current-voltage curve; determining the key parameters of the maximum power point tracking algorithm corresponding to each voltage interval; the key parameters at least include one or more of the following: perturbation compensation, power threshold and waiting time; the waiting time is the waiting time for obtaining the power after the maximum power point tracking algorithm perturbs the photovoltaic component; and determining the maximum output power of the photovoltaic component based on the key parameters corresponding to each voltage interval and the maximum power point tracking algorithm.

[0006] In the embodiments of the present application, firstly, the first current-voltage curve and the second current-voltage curve of the photovoltaic component can be used to determine a plurality of voltage intervals, so that the different degrees of hysteresis effect of the photovoltaic component in the process of voltage change can be reflected through the plurality of voltage intervals. Then, the maximum output power of the photovoltaic component is determined based on the key parameters corresponding to each voltage interval and the maximum power point tracking algorithm, so that the different degrees of hysteresis effect in the process of voltage change are fully considered. Therefore, under different degrees of hysteresis, the maximum power point tracking algorithm and the corresponding key parameters that are suitable for the degree of hysteresis can be selected by dynamically adjusting the applied maximum power point tracking algorithm and the corresponding key parameters, so that the maximum output power of the photovoltaic component can be efficiently tracked, the tracking accuracy of the maximum output power of the photovoltaic component is improved, and the power generation performance of the photovoltaic component is improved.

[0007] In some embodiments, based on the first current-voltage curve and the second current-voltage curve, a plurality of voltage intervals are determined, including: the first current-voltage curve and the second current-voltage curve are correspondingly divided into a plurality of voltage intervals; wherein, for the same voltage interval, the voltage range corresponding to the first current-voltage curve and the voltage range corresponding to the second current-voltage curve are consistent.

[0008] In the above embodiment, by the current difference between the first current-voltage curve and the second current-voltage curve of the photovoltaic module, the first current-voltage curve and the second current-voltage curve can be divided into a plurality of voltage intervals, so that the different degrees of hysteresis effect of the photovoltaic module in the process of voltage change can be reflected through the plurality of voltage intervals.

[0009] In some embodiments, the first current-voltage curve and the second current-voltage curve are correspondingly divided into a plurality of voltage intervals, including: a plurality of first currents corresponding to the first current-voltage curve and a plurality of second currents corresponding to the second current-voltage curve are respectively obtained at a preset voltage interval; the current difference between the first current and the second current at the same voltage is determined; based on the size relationship between the plurality of current differences and the preset at least one first difference threshold, the first current-voltage curve and the second current-voltage curve are correspondingly divided into a plurality of voltage intervals.

[0010] In the above embodiment, first, based on the current difference between the first current and the second current, and the preset at least one first difference threshold, the first current-voltage curve and the second current-voltage curve are correspondingly divided into a plurality of voltage intervals; then, since each first difference threshold is a change threshold of the hysteresis degree of the photovoltaic module in the running process, each voltage interval obtained by the division corresponds to different hysteresis degrees of the photovoltaic module, so that different voltage intervals can be configured with the maximum power point tracking algorithm and the corresponding key parameters suitable for the voltage interval.

[0011] In some embodiments, based on the first current-voltage curve and the second current-voltage curve, a plurality of voltage intervals are determined, including: determining a first power-voltage curve corresponding to the first current-voltage curve, and a second power-voltage curve corresponding to the second current-voltage curve; the first power-voltage curve and the second power-voltage curve are correspondingly divided into a plurality of voltage intervals; wherein, for the same voltage interval, the voltage range corresponding to the first power-voltage curve and the voltage range corresponding to the second power-voltage curve are consistent.

[0012] In the above embodiment, first, the first power-voltage curve and the second power-voltage curve can be divided into multiple voltage intervals by the power difference between the first power-voltage curve and the second power-voltage curve, so that the different degrees of hysteresis of the photovoltaic module in the process of voltage change can be reflected by the multiple voltage intervals, and thus the maximum power point tracking algorithm and the key parameters suitable for the hysteresis degree can be selected under different hysteresis degrees, so as to realize efficient tracking of the maximum output power of the photovoltaic module, improve the tracking accuracy of the maximum output power of the photovoltaic module, and further improve the power generation performance of the photovoltaic module.

[0013] In some embodiments, the first power-voltage curve and the second power-voltage curve are correspondingly divided into multiple voltage intervals, including: obtaining multiple first powers corresponding to the first power-voltage curve and multiple second powers corresponding to the second power-voltage curve at a preset voltage interval; determining the power difference between the first power and the second power at the same voltage; and based on the size relationship between the multiple power differences and at least one second difference threshold, the first power-voltage curve and the second power-voltage curve are correspondingly divided into multiple voltage intervals.

[0014] In the above embodiment, first, the first power-voltage curve and the second power-voltage curve are correspondingly divided into multiple voltage intervals based on the power difference between the first power and the second power and at least one second difference threshold; then, since each second difference threshold is a change threshold of the hysteresis degree of the photovoltaic module in the running process, each voltage interval obtained by the division corresponds to a different hysteresis degree of the photovoltaic module, so that the maximum power point tracking algorithm and the corresponding key parameters suitable for the voltage interval can be configured for different voltage intervals.

[0015] In some embodiments, the first current-voltage curve and the second current-voltage curve are correspondingly divided into multiple first voltage intervals; the first power-voltage curve and the second power-voltage curve are correspondingly divided into multiple second voltage intervals; and interval operations are performed on the multiple first voltage intervals and the multiple second voltage intervals to determine the multiple voltage intervals.

[0016] In the above embodiment, first, the photovoltaic module is divided into multiple first voltage intervals by considering the different degrees of hysteresis of the photovoltaic module in the current dimension; then, the photovoltaic module is divided into multiple second voltage intervals by considering the different degrees of hysteresis of the photovoltaic module in the power dimension; and finally, interval operations are performed on the multiple first voltage intervals and the multiple second voltage intervals to determine the multiple voltage intervals, so that the degrees of hysteresis of the photovoltaic module in the current dimension and in the power dimension are comprehensively considered, and the multiple voltage intervals obtained make the division of the voltage intervals of the photovoltaic module more precise, thereby improving the tracking accuracy of the maximum output power of the photovoltaic module.

[0017] In some embodiments, the determining the key parameter of the maximum power point tracking algorithm corresponding to each voltage interval comprises: when the maximum power point tracking algorithm is single, determining the key parameter of the maximum power point tracking algorithm corresponding to each voltage interval; when the maximum power point tracking algorithm is multiple, determining the maximum power point tracking algorithm corresponding to each voltage interval, and determining the key parameter corresponding to the maximum power point tracking algorithm.

[0018] In the above embodiments, two different methods for determining the key parameter are proposed, so that the determination method of the key parameter can be matched according to the number of the maximum power point tracking algorithm, and the dynamic adjustment of the photovoltaic resistance to the maximum power point tracking algorithm and the corresponding key parameter under different hysteresis degrees is realized. When the maximum power point tracking algorithm is multiple, the maximum power point tracking algorithm corresponding to each voltage interval is determined first, and then the key parameter corresponding to the maximum power point tracking algorithm is determined, so as to solve the problem that the maximum power point tracking algorithm does not correspond to its key parameter.

[0019] In some embodiments, the first current-voltage curve obtained by forward scanning and the second current-voltage curve obtained by reverse scanning of the photovoltaic module comprise: receiving the first voltage and the first current measured by the inverter connected to the photovoltaic module in the forward scanning process, and the second voltage and the second current measured by the inverter in the reverse scanning process; determining the first current-voltage curve based on the first voltage and the first current; determining the second current-voltage curve based on the second voltage and the second current.

[0020] In the above embodiments, after receiving the first voltage and the first current measured by the inverter in the forward scanning process, and the second voltage and the second current measured by the inverter in the reverse scanning process, the first current-voltage curve and the second current-voltage curve can be obtained, so that through the first current-voltage curve and the second current-voltage curve, the change of the hysteresis effect of the photovoltaic module in the running process can be determined, and then the number of the first difference threshold or the second difference threshold can be determined.

[0021] In another aspect, the embodiments of the present application provide a photovoltaic system, which comprises a photovoltaic assembly and an inverter; the inverter comprises a control module and a detection module; wherein the inverter is connected with the photovoltaic assembly, the detection module is configured to perform forward scanning and reverse scanning on the photovoltaic assembly at a preset frequency, and output a first voltage and a first current measured in the forward scanning process and a second voltage and a second current measured in the reverse scanning process to the control module; the control module is configured to acquire a first current-voltage curve obtained through the forward scanning and a second current-voltage curve obtained through the reverse scanning; determine a plurality of voltage intervals based on the first current-voltage curve and the second current-voltage curve; determine a key parameter of a maximum power point tracking algorithm corresponding to each voltage interval; the key parameter comprises at least one or more of the following: perturbation compensation, power threshold and waiting time; the waiting time is a waiting time for acquiring power after the maximum power point tracking algorithm performs perturbation on the photovoltaic assembly; and determine a maximum output power of the photovoltaic assembly in each voltage interval based on the key parameter of the maximum power point tracking algorithm corresponding to each voltage interval.

[0022] In the embodiments of the present application, the first current and the first voltage output by the detection module can obtain a first current-voltage curve of the photovoltaic assembly, and the second current and the second voltage output by the detection module can obtain a second current-voltage curve of the photovoltaic assembly. In this way, the first current-voltage curve and the second current-voltage curve can determine a plurality of voltage intervals, so that the plurality of voltage intervals can reflect different degrees of hysteresis effects of the photovoltaic assembly in the process of voltage change. Then, the maximum output power of the photovoltaic assembly is determined based on the key parameter of the maximum power point tracking algorithm corresponding to each voltage interval. In this way, different degrees of hysteresis effects in the process of voltage change are fully considered, so that under different degrees of hysteresis, the maximum power point tracking algorithm and the corresponding key parameter suitable for the degree of hysteresis are selected by dynamically adjusting the applied maximum power point tracking algorithm and the corresponding key parameter, which can realize efficient tracking of the maximum output power of the photovoltaic assembly, improve the tracking accuracy of the maximum output power of the photovoltaic assembly, and further improve the power generation performance of the photovoltaic assembly.

[0023] In yet another aspect, the embodiments of the present application provide a computer readable storage medium having a computer program stored thereon, which is executed by the photovoltaic system to implement some or all of the steps of the above method.

[0024] In yet another aspect, the embodiments of the present application provide a computer program product comprising a computer program or instructions, which is executed by the photovoltaic system to implement some or all of the steps of the above method.

[0025] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, but not limiting the technical solutions of the present application. Attached Figure Description

[0026] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the specification, serve to explain the technical solutions of this application.

[0027] Figure 1 A schematic diagram illustrating the implementation process of a maximum power point tracking method provided in this application embodiment;

[0028] Figure 2 A schematic diagram of the current-voltage curve of a perovskite solar cell provided in this application embodiment. Figure 1 ;

[0029] Figure 3 A schematic diagram of the power-voltage curve of a perovskite solar cell provided in an embodiment of this application;

[0030] Figure 4 A schematic diagram of a photovoltaic system provided in an embodiment of this application;

[0031] Figure 5 A schematic diagram illustrating the hysteresis effect of a perovskite solar cell provided in an embodiment of this application;

[0032] Figure 6 A schematic diagram illustrating the implementation process of a perturbation observation method provided in an embodiment of this application;

[0033] Figure 7 A schematic diagram illustrating the implementation process of a maximum power point tracking method for a perovskite solar cell provided in this application embodiment;

[0034] Figure 8 A schematic diagram of the current-voltage curve of a perovskite solar cell provided in this application embodiment. Figure 2 ;

[0035] Figure 9 This is a comparison diagram of the output power obtained by the maximum power point tracking method proposed in this application and the output power obtained by related technologies, provided in an embodiment of this application. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application are further described in detail below with reference to the accompanying drawings and embodiments. The described embodiments should not be regarded as limitations on this application. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0037] In the following description, reference is made to "some embodiments" which describe only a subset of all possible embodiments, and which can be combined with each other and with other embodiments without conflicts.

[0038] It should be noted that the terms "first", "second", "third" and the like in the description do not denote any order, quantity, number or importance, but are used to distinguish one element from another, and can be understood as a specific order or sequence, if permitted, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein.

[0039] Those skilled in the art can understand that, unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art to which the embodiments of the present application belong. It should also be understood that terms such as those defined in a general dictionary should be understood as having a meaning consistent with that in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless specifically defined as such herein.

[0040] The embodiments of the present application provide a maximum power point tracking method, applied to a photovoltaic system, the photovoltaic system comprising a photovoltaic assembly and an inverter; the inverter comprising a detection module and a control module; the inverter being connected with the photovoltaic assembly; as shown in Figure 1 The maximum power point tracking method can comprise steps S101 to S104:

[0041] Step S101: obtaining a first current-voltage curve obtained by forward scanning of the photovoltaic assembly, and a second current-voltage curve obtained by reverse scanning of the photovoltaic assembly;

[0042] Here, the photovoltaic assembly refers to a component that converts sunlight into electrical energy using the photovoltaic effect; forward scanning refers to scanning from low voltage (or current) to high voltage (or current); reverse scanning refers to scanning from high voltage (or current) to low voltage (or current).

[0043] In some embodiments, the photovoltaic module can be selected from a photovoltaic cell with hysteresis effect, for example, a perovskite cell, a crystalline silicon cell with hysteresis effect. Further, the hysteresis effect is described as follows: during the charging and discharging process of the cell, the change of the cell voltage or open circuit voltage does not completely follow the change of the cell power, but there is a certain hysteresis. Specifically, when the cell power increases, the voltage rises slowly, that is, the voltage is low; when the cell power decreases, the voltage also decreases slowly, that is, the voltage is high. In the case of a perovskite solar cell, the hysteresis effect mainly manifests as the current-voltage curve obtained by forward scanning and the current-voltage curve obtained by reverse scanning do not completely coincide.

[0044] In some embodiments, in the case that the inverter supports scanning of the photovoltaic module, the inverter can perform forward scanning and reverse scanning on the photovoltaic module at a preset frequency.

[0045] In some embodiments, in the case that the inverter does not support scanning of the photovoltaic module, the first current-voltage curve and the second current-voltage curve obtained under the initial standard test condition of the photovoltaic module can be used as the reference curve for subsequent operations.

[0046] In some embodiments, the photovoltaic module can also be periodically subjected to offline forward scanning and reverse scanning, that is, the photovoltaic module is subjected to forward scanning and reverse scanning when the photovoltaic module is disconnected from the inverter. The first current-voltage curve and the second current-voltage curve obtained by offline scanning can be used as the reference curve for subsequent operations.

[0047] In some embodiments, the first current-voltage (IV) curve can be obtained based on the first voltage and the first current of the photovoltaic module measured during the forward scanning process; the second current-voltage curve can be obtained based on the second voltage and the second current of the photovoltaic module measured during the reverse scanning process.

[0048] In some embodiments, the forward scanning can be scanning in the direction from 0 volt (V) to the open circuit voltage; the reverse scanning can be scanning in the direction from the open circuit voltage to 0 V.

[0049] Taking a perovskite solar cell as an example, the first current-voltage curve and the second current-voltage curve are described as follows: Figure 2 As shown in FIG. 1, the dashed line represents the first current-voltage curve, and the solid line represents the second current-voltage curve. It can be seen that the first current-voltage curve and the second current-voltage curve do not completely coincide, and the perovskite solar cell has hysteresis effect.

[0050] Step S102: determining a plurality of voltage intervals based on the first current-voltage curve and the second current-voltage curve;

[0051] In some embodiments, the step S102 can include: dividing the first current-voltage curve and the second current-voltage curve into a plurality of voltage intervals; wherein, for the same voltage interval, the voltage range corresponding to the first current-voltage curve and the voltage range corresponding to the second current-voltage curve are consistent.

[0052] Here, the plurality of voltage intervals refers to at least two voltage intervals, for example, 2 voltage intervals, 5 voltage intervals.

[0053] In some embodiments, the first current-voltage curve and the second current-voltage curve are plotted in the same coordinate, and the current difference between the first current-voltage curve and the second current-voltage curve can reflect the hysteresis effect of the photovoltaic module. For example, when the current difference is large, it indicates that the hysteresis effect of the photovoltaic module is serious, and when the current difference is 0, it indicates that the photovoltaic module does not currently have a hysteresis effect.

[0054] In some embodiments, the first current-voltage curve and the second current-voltage curve are divided based on different degrees of hysteresis effect.

[0055] It should be noted that the plurality of voltage intervals includes a plurality of forward scanning intervals corresponding to the first current-voltage curve and a plurality of reverse scanning intervals corresponding to the second current-voltage curve, wherein the plurality of forward scanning intervals and the plurality of reverse scanning intervals correspond one-to-one, that is, the interval range of the plurality of forward scanning intervals is the same as the interval range of the plurality of reverse scanning intervals.

[0056] In some embodiments, first, a plurality of first voltages are obtained in the first current-voltage curve in a voltage range of 0 volts (V) - open circuit voltage (Voc) with a preset voltage interval; a plurality of second voltages are obtained in the second current-voltage curve in a voltage range of open circuit voltage - 0V with a preset voltage interval; wherein the plurality of first voltages and the plurality of second voltages correspond one-to-one, that is, the voltage values corresponding to the plurality of first voltages are equal to the voltage values corresponding to the plurality of second voltages. Then, the first current corresponding to each first voltage and the second current corresponding to each second voltage are determined; finally, the current difference between each first current and the second current corresponding to the first current is determined.

[0057] In some embodiments, the first current-voltage curve and the second current-voltage curve can be divided into a plurality of voltage intervals based on the current difference and at least one first difference threshold.

[0058] In the above embodiments, the first current-voltage curve and the second current-voltage curve of the photovoltaic module can be divided into a plurality of voltage intervals through the current difference between the first current-voltage curve and the second current-voltage curve, so that the plurality of voltage intervals can reflect different degrees of hysteresis effect of the photovoltaic module during voltage change.

[0059] Step S103: determining a key parameter of the maximum power point tracking algorithm corresponding to each voltage interval; the key parameter at least includes one or more of the following: perturbation compensation, power threshold and waiting time; the waiting time is the waiting time for obtaining power after the maximum power point tracking algorithm perturbs the photovoltaic module;

[0060] Here, the maximum power point tracking algorithm is the core technology in the photovoltaic system, which aims to adjust the output power of the photovoltaic module according to different environmental temperature, light intensity and other characteristics of the outside world, so that it always remains in the maximum power output state. The perturbation compensation refers to the value of the perturbation signal applied to the operating voltage or current of the photovoltaic module; the power threshold is used to set when the maximum power point tracking algorithm stops tracking or adjusts the working point of the maximum power point tracking algorithm.

[0061] In some embodiments, when the maximum power point tracking algorithm is single, the key parameter corresponding to each voltage interval can be preset.

[0062] In some embodiments, a plurality of difference value intervals can be determined based on at least one preset first difference value threshold, and then the key parameter corresponding to each first difference value interval can be preset.

[0063] For example, when the plurality of first difference value thresholds is 2, the first difference value interval, the second difference value interval and the third difference value interval can be determined, each difference value interval corresponds to a different degree of hysteresis effect of the photovoltaic module, so that the key parameter corresponding to each difference value interval can be set in advance based on the hysteresis degree corresponding to the difference value interval.

[0064] In some embodiments, the difference value interval corresponding to each voltage interval can be determined first, and then the key parameter corresponding to the difference value interval can be obtained based on the difference value interval.

[0065] In some embodiments, when the maximum power point tracking algorithm is multiple, the maximum power point tracking algorithm corresponding to each voltage interval can be preset, and the key parameter corresponding to the maximum power point tracking algorithm can be preset.

[0066] In some embodiments, a plurality of difference value intervals can be determined based on at least one preset first difference value threshold, and then the maximum power point tracking algorithm corresponding to each first difference value interval and the key parameter corresponding to the maximum power point tracking algorithm can be preset.

[0067] For example, when the plurality of first difference value thresholds is 1, the fourth difference value interval and the fifth difference value interval can be determined, each difference value interval corresponds to a different degree of hysteresis effect of the photovoltaic module, so that the maximum power point tracking algorithm adapted to each difference value interval and the key parameter corresponding to the tracking algorithm can be set in advance based on the hysteresis degree corresponding to each difference value interval.

[0068] In some embodiments, the difference interval corresponding to each voltage interval can be determined first, then the maximum power point tracking algorithm corresponding to the difference interval is obtained, and finally the key parameter corresponding to the maximum power point tracking algorithm is determined.

[0069] Step S104: determining the maximum output power of the photovoltaic module based on the key parameter and the maximum power point tracking algorithm corresponding to each voltage interval.

[0070] In some embodiments, when the maximum power point tracking algorithm is single, the maximum output power of the photovoltaic module is obtained by substituting the key parameter corresponding to each voltage interval into the maximum power point tracking algorithm.

[0071] In some embodiments, when the maximum power point tracking algorithm is multiple, the maximum output power of the photovoltaic module is obtained by substituting the key parameter corresponding to each voltage interval into the maximum power point tracking algorithm corresponding to the voltage interval.

[0072] In the embodiments of the present application, first, the first current-voltage curve and the second current-voltage curve of the photovoltaic module can be used to determine a plurality of voltage intervals, so that the different degrees of hysteresis effect of the photovoltaic module in the process of voltage change can be reflected through the plurality of voltage intervals; then, the maximum output power of the photovoltaic module is determined based on the key parameter and the maximum power point tracking algorithm corresponding to each voltage interval, so that the different degrees of hysteresis in the process of voltage change are fully considered, thereby under different degrees of hysteresis, the maximum power point tracking algorithm and the corresponding key parameter suitable for the degree of hysteresis are selected by dynamically adjusting the applied maximum power point tracking algorithm and the corresponding key parameter, the maximum output power of the photovoltaic module can be tracked efficiently, the tracking accuracy of the maximum output power of the photovoltaic module is improved, and the power generation performance of the photovoltaic module is improved.

[0073] In some embodiments, dividing the first current-voltage curve and the second current-voltage curve into a plurality of voltage intervals can include steps S1021 to S1023:

[0074] Step S1021: obtaining a plurality of first currents corresponding to the first current-voltage curve and a plurality of second currents corresponding to the second current-voltage curve at a preset voltage interval, respectively;

[0075] Step S1022: determining the current difference between the first current and the second current under the same voltage;

[0076] Here, the calculation of the current difference is shown in formula (1):

[0077]

[0078] Where, σ I I represents the current difference. B I represents the first current. F This indicates the second current.

[0079] Step S1023: Based on the relationship between multiple current differences and at least one preset first difference threshold, the first current-voltage curve and the second current-voltage curve are respectively divided into multiple voltage intervals.

[0080] Here, size relationship usually refers to the comparison between numbers, which mainly reflects the relationship and properties between elements. It generally refers to the relationship of being greater than, equal to, and less than, or it can also refer to the relationship of being greater than or equal to and less than or equal to.

[0081] In some implementations, the determination of the number of first difference thresholds can be related to the hysteresis of the photovoltaic module. Taking perovskite solar cells as an example, for instance... Figure 2 As shown, the hysteresis of perovskite solar cells can be divided into three stages. In the first stage, no hysteresis or a slight hysteresis effect is observed, and the first current-voltage curve and the second current-voltage curve have a high degree of overlap. In the second stage, the hysteresis effect intensifies, and the first current-voltage curve and the second current-voltage curve have a low degree of overlap. In the third stage, the hysteresis effect is severe, and the first current-voltage curve and the second current-voltage curve have the lowest degree of overlap. Therefore, based on the hysteresis of perovskite solar cells, the number of the first difference thresholds can be determined to be 2.

[0082] For example, when the first difference thresholds are a1 and b1 respectively, when |σ I When | ≤ a1, determine the first interval; when a1 < |σ I When | ≤ b1, determine the second interval; when b1 < |σ I When |, determine the third interval. Here, a1 can take the value 5%, and b1 can take the value 10%.

[0083] In the above embodiments, firstly, based on the current difference between the first current and the second current, and at least one preset first difference threshold, the first current-voltage curve and the second current-voltage curve are divided into multiple voltage intervals. Then, since each first difference threshold is a threshold for the change in the hysteresis degree of the photovoltaic module during operation, each voltage interval obtained in this way corresponds to a different hysteresis degree of the photovoltaic module, thereby allowing the configuration of a maximum power point tracking algorithm and corresponding key parameters suitable for that voltage interval for different voltage intervals.

[0084] In some embodiments, the step S102 of determining the plurality of voltage intervals based on the first current-voltage curve and the second current-voltage curve can include steps S105 and S106:

[0085] The step S105 includes determining a first power-voltage curve corresponding to the first current-voltage curve, and a second power-voltage curve corresponding to the second current-voltage curve.

[0086] Here, the power-voltage (PV) curve is a graphical representation of the output power of a photovoltaic module as a function of voltage under specific illumination and temperature conditions, with the horizontal axis representing voltage (V) and the vertical axis representing power (P).

[0087] In some embodiments, first, a first power is obtained based on the first voltage and the first current of the photovoltaic module measured during the forward scanning process, and a second power is obtained based on the second voltage and the second current of the photovoltaic module measured during the reverse scanning process. Then, a first power-voltage curve is obtained based on the first power and the first voltage, and a second power-voltage curve is obtained based on the second power and the second voltage.

[0088] For example, a perovskite solar cell is taken as an example to illustrate the first power-voltage curve and the second power-voltage curve, as shown in FIG. 1, where the dashed line represents the first power-voltage curve and the solid line represents the second power-voltage curve. It can be seen that the first power-voltage curve and the second power-voltage curve do not completely coincide, and the perovskite solar cell has a hysteresis effect. Figure 3

[0089] The step S106 includes dividing the first power-voltage curve and the second power-voltage curve into a plurality of voltage intervals, and for the same voltage interval, the voltage range corresponding to the first power-voltage curve and the voltage range corresponding to the second power-voltage curve are consistent.

[0090] In some embodiments, the first power-voltage curve and the second power-voltage curve are plotted in the same coordinate, and the power difference between the first power-voltage curve and the second power-voltage curve can reflect the hysteresis effect of the photovoltaic module. For example, when the power difference is large, it indicates that the hysteresis effect of the photovoltaic module is serious, and when the power difference is 0, it indicates that the photovoltaic module does not currently have a hysteresis effect.

[0091] In some embodiments, the first power-voltage curve and the second power-voltage curve are divided based on different degrees of hysteresis effect.

[0092] ​It should be noted that the plurality of voltage intervals includes a plurality of first power voltage intervals corresponding to the first power voltage curve and a plurality of second power voltage intervals corresponding to the second power voltage curve, wherein the plurality of first power voltage intervals and the plurality of second power voltage intervals are one-to-one correspondence, that is, the interval range of the plurality of first power voltage intervals is the same as the interval range of the plurality of second power voltage intervals.

[0093] In some embodiments, first, a plurality of first voltages are obtained in the first power voltage curve at a preset voltage interval in the voltage range of 0 volt (V) - open circuit voltage; a plurality of second voltages are obtained in the second power voltage curve interval at a preset voltage interval in the voltage range of open circuit voltage - 0V; wherein the plurality of first voltages and the plurality of second voltages are one-to-one correspondence, that is, the voltage values corresponding to the plurality of first voltages are equal to the voltage values corresponding to the plurality of second voltages. Then, the first power corresponding to each first voltage is determined, and the second power corresponding to each second voltage is determined; finally, the power difference between each first power and the second power corresponding to the first power is determined.

[0094] In some embodiments, the first power voltage curve and the second power voltage curve can be divided into a plurality of voltage intervals based on the power difference and the preset at least one second difference threshold.

[0095] In the above embodiment, first, the first power voltage curve and the second power voltage curve of the photovoltaic module can be divided into a plurality of voltage intervals through the power difference between the first power voltage curve and the second power voltage curve, so that the different degrees of hysteresis effect of the photovoltaic module in the process of voltage change can be reflected through the plurality of voltage intervals, thereby selecting the maximum power point tracking algorithm and the key parameter suitable for the hysteresis degree under different hysteresis degrees, and the maximum output power of the photovoltaic module can be efficiently tracked, the tracking accuracy of the maximum output power of the photovoltaic module is improved, and the power generation performance of the photovoltaic module is improved.

[0096] In some embodiments, the step S106 of dividing the first power voltage curve and the second power voltage curve into a plurality of voltage intervals includes steps S1061 to S1063:

[0097] Step S1061: obtaining a plurality of first powers corresponding to the first power voltage curve and a plurality of second powers corresponding to the second power voltage curve at a preset voltage interval, respectively;

[0098] Step S1062: determining the power difference between the first power and the second power under the same voltage;

[0099] Here, the calculation of the power difference is shown in formula (2):

[0100]

[0101] wherein, σ p represents the current difference value, P B represents the first current, P F represents the second current.

[0102] Step S1063: based on the size relationship between the plurality of power difference values and the at least one preset second difference threshold, the first power-voltage curve and the second power-voltage curve are respectively divided into a plurality of voltage intervals.

[0103] In some embodiments, the determination of the number of second difference thresholds can be related to the hysteresis degree of the photovoltaic module. Taking a perovskite solar cell as an example, as shown in FIG. 6, it can be seen that the hysteresis degree of the perovskite solar cell can be divided into three stages. In the first stage, no hysteresis effect or slight hysteresis effect occurs, and the first power-voltage curve and the second power-voltage curve have a relatively high degree of coincidence. In the second stage, the hysteresis effect is enhanced, and the first power-voltage curve and the second power-voltage curve have a relatively low degree of coincidence. In the third stage, the hysteresis effect is serious, and the first power-voltage curve and the second power-voltage curve have the lowest degree of coincidence. Therefore, according to the hysteresis degree of the perovskite solar cell, the number of second difference thresholds can be determined as 2. Figure 3

[0104] For example, in the case where the second difference thresholds are a2 and b2 respectively, when |σ p |≤a2, the first interval is determined; when a2<|σ p |≤b2, the second interval is determined; and when b2<|σ p |, the third interval is determined. Wherein, a2 can take a value of 5%, and b2 can take a value of 10%.

[0105] In the above embodiment, first, based on the power difference value between the first power and the second power, and the at least one preset second difference threshold, the first power-voltage curve and the second power-voltage curve are respectively divided into a plurality of voltage intervals. Then, since each second difference threshold is a change threshold of the hysteresis degree of the photovoltaic module in the running process, each voltage interval obtained by the division corresponds to a different hysteresis degree of the photovoltaic module, so that the different voltage intervals can be configured with the maximum power point tracking algorithm and the corresponding key parameters suitable for the voltage interval.

[0106] In some embodiments, the above maximum power point tracking method can further comprise steps S107 to S109 after step S101:

[0107] Step S107: the first current-voltage curve and the second current-voltage curve are respectively divided into a plurality of first voltage intervals. ​

[0108] Step S108: dividing the first power voltage curve and the second power voltage curve into a plurality of second voltage intervals correspondingly;

[0109] Step S109: performing interval operation on the plurality of first voltage intervals and the plurality of second voltage intervals to determine a plurality of voltage intervals.

[0110] Here, the interval operation refers to performing intersection or union operation on the plurality of first voltage intervals and the plurality of second voltage intervals.

[0111] In some embodiments, intersection processing can be performed on the plurality of first voltage intervals and the plurality of second voltage intervals to determine the plurality of voltage intervals. In other embodiments, union processing can be performed on the plurality of first voltage intervals and the plurality of second voltage intervals to determine the plurality of voltage intervals.

[0112] In the above embodiments, first, the photovoltaic module is divided into a plurality of first voltage intervals by considering the different degrees of hysteresis effect of the photovoltaic module in the current dimension; then, the photovoltaic module is divided into a plurality of second voltage intervals by considering the different degrees of hysteresis effect of the photovoltaic module in the power dimension; finally, interval operation is performed on the plurality of first voltage intervals and the plurality of second voltage intervals to determine a plurality of voltage intervals. In this way, the degrees of hysteresis of the photovoltaic module in the current dimension and in the power dimension are comprehensively considered, and the plurality of voltage intervals obtained make the division of the voltage intervals of the photovoltaic module more precise, thereby improving the tracking accuracy of the maximum output power of the photovoltaic module.

[0113] In some embodiments, the step S103 of determining the key parameters of the maximum power point tracking algorithm corresponding to each voltage interval includes steps S1031 and S1032:

[0114] Step S1031: when the maximum power point tracking algorithm is single, determining the key parameters of the maximum power point tracking algorithm corresponding to each voltage interval;

[0115] Step S1032: when the maximum power point tracking algorithm is multiple, determining the maximum power point tracking algorithm corresponding to each voltage interval, and determining the key parameters corresponding to the maximum power point tracking algorithm.

[0116] In the above embodiments, two different methods of determining the key parameters are proposed, so that the determination method of the key parameters can be matched according to the number of the maximum power point tracking algorithm, and the dynamic adjustment of the maximum power point tracking algorithm and the corresponding key parameters of the photovoltaic resistance under different degrees of hysteresis is realized. When the maximum power point tracking algorithm is multiple, the maximum power point tracking algorithm corresponding to each voltage interval is determined first, and then the key parameters corresponding to the maximum power point tracking algorithm are determined, which solves the problem that the maximum power point tracking algorithm does not correspond to its key parameters.

[0117] In some embodiments, the step S101 of obtaining the first current-voltage curve obtained by the forward scanning and the second current-voltage curve obtained by the reverse scanning of the photovoltaic module comprises steps S1011-S1013:

[0118] The step S1011 comprises: receiving the first voltage and the first current measured by the inverter connected to the photovoltaic module in the process of the forward scanning and the second voltage and the second current measured by the inverter in the process of the reverse scanning, respectively.

[0119] In some embodiments, the inverter can perform the forward scanning and the reverse scanning on the photovoltaic module at a preset frequency.

[0120] The step S1012 comprises: determining the first current-voltage curve based on the first voltage and the first current.

[0121] The step S1013 comprises: determining the second current-voltage curve based on the second voltage and the second current.

[0122] In the above embodiments, after receiving the first voltage and the first current measured by the inverter in the process of the forward scanning and the second voltage and the second current measured by the inverter in the process of the reverse scanning, the first current-voltage curve and the second current-voltage curve can be obtained, so that the change of the hysteresis effect of the photovoltaic module in the process of operation can be determined by the first current-voltage curve and the second current-voltage curve, and then the number of selected first difference threshold or second difference threshold can be determined.

[0123] Embodiments of the present application provide a photovoltaic system, as shown in Figure 4 The photovoltaic system comprises a photovoltaic module 1 and an inverter 2; the inverter 2 comprises a control module 21 and a detection module 22; wherein,

[0124] The inverter 2 is connected to the photovoltaic module 1, the detection module 22 is configured to perform the forward scanning and the reverse scanning on the photovoltaic module at a preset frequency, and output the first voltage and the first current measured by the inverter in the process of the forward scanning and the second voltage and the second current measured by the inverter in the process of the reverse scanning to the control module.

[0125] The control module 21 is configured to acquire a first current-voltage curve of the photovoltaic module obtained through forward scanning and a second current-voltage curve obtained through reverse scanning; determine a plurality of voltage intervals based on the first current-voltage curve and the second current-voltage curve; determine a key parameter of a maximum power point tracking algorithm corresponding to each voltage interval; the key parameter at least includes one or more of the following: perturbation compensation, power threshold and waiting time; the waiting time is the waiting time for acquiring power after the maximum power point tracking algorithm performs perturbation on the photovoltaic module; and determine the maximum output power of the photovoltaic module based on the key parameter corresponding to each voltage interval and the maximum power point tracking algorithm.

[0126] In the embodiment of the present application, first, the first current-voltage curve of the photovoltaic module can be obtained through the first current and the first voltage output by the detection module, and the second current-voltage curve of the photovoltaic module can be obtained through the second current and the second voltage output by the detection module. In this way, through the first current-voltage curve and the second current-voltage curve, a plurality of voltage intervals can be determined, so that the different degrees of hysteresis effects of the photovoltaic module in the process of voltage change can be reflected through the plurality of voltage intervals. Then, the maximum output power of the photovoltaic module is determined based on the key parameter corresponding to each voltage interval and the maximum power point tracking algorithm. In this way, the different degrees of hysteresis effects in the process of voltage change are fully considered, so that under different degrees of hysteresis, the maximum power point tracking algorithm and the corresponding key parameter suitable for the degree of hysteresis can be selected by dynamically adjusting the applied maximum power point tracking algorithm and the corresponding key parameter, and the maximum output power of the photovoltaic module can be efficiently tracked, the tracking accuracy of the maximum output power of the photovoltaic module is improved, and the power generation performance of the photovoltaic module is improved.

[0127] The above maximum power point tracking method will be described in combination with a specific embodiment. In order to facilitate understanding, the photovoltaic cell is taken as a perovskite solar cell as an example, and the possible process suitable for the embodiment of the present application is introduced. However, it should be noted that the specific embodiment is only used to better illustrate the present application and does not constitute an improper limitation on the present application.

[0128] Due to interface defects, ion migration, and interface capacitance, perovskite solar cells exhibit a hysteresis effect different from crystalline silicon solar cells. Most existing maximum power point tracking (MPPT) algorithms for commonly used inverters are adapted to crystalline silicon solar cells, failing to consider the hysteresis effect of perovskite solar cells. This results in existing MPPT algorithms being unable to track the optimal power point of perovskite solar cells, or failing to track the optimal power point or exhibiting significantly different tracking accuracy compared to crystalline silicon solar cells under specific scenarios, such as low light or drastic irradiance changes. For example, some optimized perturbation-observation methods, such as the variable step perturbation-observation method, use large step scans to quickly approach the power peak when far from it, and switch to small step scans to reduce oscillations when approaching the power peak. However, this method does not fully consider the hysteresis characteristics of perovskite solar cells, potentially leading to situations where the optimal power point of the perovskite solar cell cannot be tracked.

[0129] The appearance of IV curves of perovskite solar cells is closely related to scanning conditions. Under different scanning conditions such as scanning speed, scanning direction, scanning step size, waiting time after scanning, heuristic voltage, light intensity, and source impedance, perovskite solar cells and crystalline silicon solar cells exhibit different IV curves.

[0130] like Figure 5 As shown, the IV curves of a perovskite solar cell are obtained by forward and reverse scanning. The horizontal axis represents voltage, and the vertical axis represents current. The dotted line represents the IV curve obtained by the reverse scanning of the perovskite solar cell, and the square line represents the IV curve obtained by the reverse scanning of the perovskite solar cell. It can be seen that there is a difference between the forward and reverse scanning of the perovskite solar cell with hysteresis effect. Since the maximum power point tracking algorithm has perturbations in different directions during the tracking process, applying the existing maximum power point tracking algorithm to the perovskite solar cell causes the perturbations to jump back and forth on the two IV curves, thus making it impossible to track the actual maximum power point.

[0131] Furthermore, while the initial hysteresis effect of perovskite solar cells can be reduced to a lower level through perovskite device design, the hysteresis effect may worsen during operation, leading to a decrease in the overlap between the forward and reverse IV curves. This results in a downward shift of the actual operating curve of the perovskite solar cell, further reducing the accuracy of the maximum power point tracking algorithm. Additionally, the hysteresis effect can also cause degradation of perovskite solar cells during operation, manifested as a decrease in the output power.

[0132] Here, the conventional perturbation method P&O method is introduced, and the step search is applied to the maximum power point tracking control of the photovoltaic system, which is called the perturbation and observation method. The main principle of the method is that the output voltage (or current) of the photovoltaic cell is first disturbed, then the output power change of the photovoltaic cell is observed, and the direction of the disturbance voltage (or current) is changed according to the trend of the output power change, so that the photovoltaic cell finally works at the maximum power point. Under normal conditions, the PV characteristic curve of the photovoltaic cell is a single-peak function with the maximum power point as the extreme value, that is, from the initial state, a limited change is made to the input signal each time, then the size and direction of the output change caused by the input signal change are measured, and finally the input of the controlled object is controlled in the required direction to adjust, thereby realizing self-optimizing control.

[0133] As shown in Figure 6 , the perturbation and observation method includes steps S601 to S609: step S601: measure I(K), U(K); here, the current value I(K) and the voltage value U(K) of the photovoltaic cell at the current time are obtained. Step S602: calculate P(K); step S603: P(K)>P(k-1); here, if yes, it is determined that the intersection point of the load characteristic and the photovoltaic cell characteristic is on the left side of the maximum power point, the voltage at the intersection point is increased through the maximum power point tracking control, and step S604 is entered; if no, it is determined that the intersection point of the load characteristic and the photovoltaic cell characteristic is on the right side of the maximum power point, the voltage at the intersection point is decreased through the maximum power point tracking control, and step S607 is entered. If the search process continues in this way, the system can finally track the maximum power point of the photovoltaic cell. Step S604: U(K)>U(k-1); here, if yes, step S605 is entered; if no, step S606 is entered. Step S605: Uref=Uref+△U; step S606: Uref=Uref-△U; step S607: U(K)<U(k-1); here, if yes, step S608 is entered; if no, step S609 is entered. Step S608: Uref=Uref-△U; step S609: Uref=Uref+△U.

[0134] The embodiments of the present application provide a maximum power point tracking method of a perovskite solar cell, as shown in Figure 7 , which can include steps S701 to S705:

[0135] Step S701: the perovskite solar cell is connected with an inverter and runs in a photovoltaic system;

[0136] Step S702: Based on the inverter IV scanning function, forward scanning and reverse scanning of the perovskite solar cell are performed to obtain the IV curve of the perovskite solar cell, including the first IV curve obtained by forward scanning and the second IV curve obtained by reverse scanning.

[0137] Here, the first IV curve obtained by forward scanning is also the first current-voltage curve in the above embodiment, and the second IV curve obtained by reverse scanning is also the second current-voltage curve in the above embodiment.

[0138] In implementation, the inverter IV scanning function is used to scan the perovskite solar cell at a certain scanning frequency to evaluate the performance of the perovskite solar cell. The scanning frequency can be 1 time / day or 1 time / week, and the application does not limit the setting of the scanning frequency, which can be set according to actual needs by those skilled in the art. The scanning includes forward scanning (0V to Voc) and reverse scanning (Voc to 0V) of the perovskite solar cell, and one forward scanning and reverse scanning are determined as a group.

[0139] The perovskite solar cell is connected to the maximum power point tracking module in the inverter to perform forward scanning and reverse scanning, and the IV curve of the perovskite solar cell at the current stage is obtained. The IV curve can describe the capacity, electrical parameter, hysteresis performance, and decay of the perovskite solar cell connected to the current maximum power point tracking module. The electrical parameter is a physical quantity describing the electrical characteristics of current, voltage, power, and the like in a circuit or electrical device; and the capacity represents the ability of the current perovskite module / string to store electrical energy.

[0140] Step S703: According to the forward scanning and reverse scanning curves, curve characteristic analysis is performed, and the curve is processed in sections.

[0141] Here, based on the IV curve of the perovskite solar cell, the current value and the power value of the perovskite solar cell at different voltage values can be obtained, so that the current change rule of the perovskite solar cell can be obtained, or the power change rule of the perovskite solar cell can be obtained, that is, the curve characteristic analysis is performed on the IV curve or the PV curve to obtain the current change rule or the power change rule of the perovskite solar cell. The PV curve is determined based on the IV curve. Further, according to the current change rule or the power change rule, the IV curve or the PV curve is processed in sections, so that the IV curve or the PV curve in each section has similar characteristics, and thus different key parameters or maximum power point tracking algorithms can be set for each section.

[0142] It should be noted that the widths of the sections can be consistent or inconsistent. The more the number of sections of the IV curve or the PV curve, the greater the calculation amount of the maximum power point tracking method, and the higher the accuracy.

[0143] Next, the segmentation method of the perovskite solar cell curve is described:

[0144] 1) Based on the IV curve: as shown in Figure 2 , first, for the voltage from 0V to Voc, at certain intervals, find the forward scan current (i.e. the first current) I B and the reverse scan current (i.e. the second current) I F corresponding to any point voltage U, calculate the difference between the forward and reverse scan currents σ I = (I B -I F ) / I B ; then, segment according to the value of σ I , when |σ I |≤a1, the corresponding characteristics of this section are: the coincidence degree of the forward and reverse scan currents is high; when a1<|σ I |≤b1, the corresponding characteristics of this section are: the coincidence degree of the forward and reverse scan currents is low; when b1<|σ I |, the corresponding characteristics of this section are: the coincidence degree of the forward and reverse scan currents is the lowest.

[0145] It should be noted that the values of a1 and b1 are set by those skilled in the art according to actual conditions. Those skilled in the art can increase the criterion interval according to actual conditions, i.e. divide the IV curve of the perovskite solar cell into more voltage interval sections.

[0146] 2) Based on the PV curve: first, according to the IV curve, multiply the current and voltage to obtain the power, and then obtain the PV curve of the perovskite solar cell; then, as shown in Figure 3 , for the voltage from 0V to Voc, at certain intervals, find the forward scan power (i.e. the first power) P B and the reverse scan power (i.e. the second power) P F corresponding to any point voltage U, calculate the difference between the forward and reverse scan powers σ P = (P B -P F ) / P B ; finally, segment according to the value of σ p , when |σ p |≤a2, the corresponding characteristics of this section are: the forward and reverse scan powers are close; when a2<|σ p |≤b2, the corresponding characteristics of this section are: there is a certain difference between the forward and reverse scan powers, and when b2<|σ p |, the corresponding characteristics of this section are: the difference between the forward and reverse powers is large.

[0147] It should be noted that the values of a2 and b2 are set by those skilled in the art according to actual conditions. Those skilled in the art increase the criterion interval according to actual conditions, that is, the PV curve of the perovskite solar cell is divided into more voltage interval segments.

[0148] 3) Based on the IV curve and the PV curve: first, the IV curve and the PV curve are segmented respectively, and then the curve segment intervals of the IV curve and the PV curve are processed by intersection or union according to the curve segmentation of the IV curve and the PV curve.

[0149] The interval segment structure of the perovskite solar cell curve is as follows:

[0150] Interval segment 1: (0, V1)

[0151] Interval segment 2: (V1, V2)

[0152] …

[0153] Interval segment n-1: (Vn-1, Voc)

[0154] Step S704: identifying key parameters, setting corresponding algorithms or values of key parameters for each segment;

[0155] Here, the key parameters are adjustment parameters in the maximum power point tracking algorithm, which can be parameters such as perturbation step (i.e. voltage change, StepSize), power threshold (DeltaPmin), and waiting time (DelayTime).

[0156] Among them, the waiting time (DelayTime) is a new parameter, which represents the value waiting time of the power of the perovskite solar cell after each perturbation, which is not involved in the conventional maximum power point tracking algorithm of crystalline silicon solar cells. This is because the perovskite solar cell has a hysteresis effect. After the voltage of the perovskite solar cell is perturbed (i.e. after the voltage changes), the current of the perovskite solar cell needs a certain time to reach a new steady state, so the current value of the perovskite solar cell needs to be obtained after the current reaches the steady state, that is, the determination of the waiting time is related to the hysteresis of the perovskite solar cell.

[0157] It should be noted that the setting value of the key parameter or the value equation of the key parameter in each segment is set by those skilled in the art according to the state or operation rule of the perovskite solar cell.

[0158] Alternatively, the key parameter in each interval segment can be a specific value, and each key parameter is an array containing the value of a key parameter in each interval segment, for example:

[0159] StepSize: Array_StepSize: [s1, s2, s3, … sn]

[0160] DeltaPmin: Array_DeltaPmin: [d1, d2, d3, … dn]

[0161] DelayTime: Array_DelayTime: [t1, t2, t3, … tn]

[0162] Optionally, the key parameters in each interval are a calculation method, that is, the key parameters are calculated according to the sampling values in the running, in this case, each key parameter is a segmented function of a dependent variable. In implementation, the value of the key parameter can be obtained by multiplying a preset coefficient after performing arithmetic processing on all sampling values in the interval, wherein the arithmetic processing can be an average operation, a maximum value operation or a minimum value operation, etc.

[0163] Step S705: According to the setting of the key parameters, different or the same maximum power point tracking algorithm is adopted for each segment of the curve to perform maximum power point tracking.

[0164] Here, after the setting of the algorithm of the key parameters of each segment is completed, maximum power point tracking can be performed on each segment. Taking the same maximum power point tracking algorithm for each segment of the curve as an example, for example, when the voltage of the perovskite solar cell falls into the corresponding interval segment, the value of the key parameter of the interval segment is obtained, so that the value of the key parameter of each interval segment is substituted into the perturb and observe method, and finally the maximum output power of the perovskite solar cell can be obtained. Taking the different maximum power point tracking algorithms for each segment of the curve as an example, when the voltage of the perovskite solar cell falls into the corresponding interval segment, the corresponding maximum power point tracking algorithm and the value of the corresponding key parameter of the interval segment are obtained, so that the value of the key parameter of each interval segment is substituted into the maximum power point tracking algorithm corresponding to the interval segment, and finally the maximum output power of the perovskite solar cell can be obtained.

[0165] Next, the maximum power point tracking method of the perovskite solar cell described above is specifically illustrated, wherein the maximum power point tracking algorithm corresponding to each interval segment is the same.

[0166] Firstly, the IV scan function of the inverter is used to perform forward scanning and reverse scanning on the perovskite solar cell connected with the inverter to obtain the IV curve under the current state.

[0167] Secondly, the analysis of the IV curve shows that, as shown in FIG. 2, the IV curve of the perovskite solar cell is divided into three intervals, that is, interval 1, interval 2 and interval 3. Figure 8As shown, the IV curve is divided into three sections, which are interval section 1, interval section 2 and interval section 3. Among them, the curve corresponding to the forward scan and the curve corresponding to the reverse scan in the interval section 1 are close, that is, as the voltage changes, the current of the forward scan and the reverse scan is basically unchanged; the curve corresponding to the forward scan and the curve corresponding to the reverse scan in the interval section 2 are quite different, the hysteresis effect of the perovskite solar cell in this section is heavier, which is the maximum power point appearing area, which is the main working interval; in the interval section 3, as the voltage changes, the current of the forward scan and the reverse scan decreases rapidly.

[0168] Third, based on the above description method, the difference σ between the forward and reverse scan currents is calculated I = (I B -I F ) / I B , and the voltage is divided into three interval sections, which are:

[0169] Interval section 1: (0, 25)

[0170] Interval section 2: (25, 32)

[0171] Interval section 3: (32, 40)

[0172] Fourth, according to experience, the following key parameters are selected:

[0173] (1) Perturbation step: for interval section 1, a larger perturbation step of 2V is used; for interval section 2, a smaller perturbation step of 0.3V is used; for interval section 3, a larger perturbation step of 2V is used;

[0174] (2) Power threshold: for the maximum power point and its vicinity, that is, interval section 2, in order to improve the tracking accuracy, a smaller power threshold of 0.5W is used; for interval section 1 and interval section 3, a larger power threshold of 2W is used.

[0175] (3) Waiting time after perturbation: for interval section 1, the forward and reverse scan curves are basically coincident, and no waiting time after perturbation is set; for the regions with low coincidence degree of forward and reverse scan, that is, interval section 2 and interval section 3, the waiting time after perturbation can be added each time, which is 3s.

[0176] The intervals and the key parameters corresponding to each interval are brought into the maximum power point tracking algorithm to perform maximum power point tracking, as shown in Figure 9 It can be observed that under the same working conditions, the output power of the perovskite battery obtained based on the maximum power point tracking method proposed in the present application (i.e. the curve corresponding to the optimized maximum power point tracking algorithm in the figure) is greater than the output power of the perovskite battery obtained based on the related technology (i.e. the curve corresponding to the conventional maximum power point tracking algorithm in the figure), which improves the tracking accuracy of the maximum output power of the perovskite solar cell.

[0177] The maximum power point tracking method of the perovskite solar cell provided in the embodiments of the present application dynamically adjusts key parameters according to the voltage section, finally realizes efficient tracking of the maximum power point of the perovskite solar cell, improves the tracking accuracy of the maximum power point, and further improves the power generation performance of the perovskite solar cell.

[0178] It should be noted that, in the embodiments of the present application, if the state monitoring method is implemented in the form of a software function module and is sold or used as an independent product, it can also be stored in a computer-readable storage medium. Based on this understanding, the technical solutions of the embodiments of the present application can be embodied in the form of a software product, which is stored in a storage medium and includes a plurality of instructions for causing a photovoltaic system to execute all or part of the methods of the embodiments of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a magnetic disk or an optical disk, and various storage media that can store program codes. Thus, the embodiments of the present application are not limited to any specific hardware, software or firmware, or any combination of hardware, software and firmware.

[0179] The embodiments of the present application provide a computer-readable storage medium having a computer program stored thereon, the computer program being executed by a photovoltaic system to implement part or all of the steps of the above method. The computer-readable storage medium can be transitory or non-transitory.

[0180] The embodiments of the present application provide a computer program including computer-readable code, wherein a control module in a photovoltaic system executes part or all of the steps of the above method when the computer-readable code is running in the photovoltaic system.

[0181] The embodiments of the present application provide a computer program product including a computer program or instructions, which, when executed by a photovoltaic system, implement the steps of the above method.

[0182] The computer program product can be specifically implemented by hardware, software or a combination thereof. In some embodiments, the computer program product is specifically embodied as a computer storage medium, and in other embodiments, the computer program product is specifically embodied as a software product, such as a software development kit (SDK) and the like.

[0183] It should be noted that the above-mentioned description of the various embodiments is inclined to emphasize the differences between the various embodiments, and the same or similar parts can be referred to each other. The above description of the storage medium, computer program and computer program product embodiments is similar to the description of the above method embodiments, and has similar beneficial effects as the method embodiments. For technical details not disclosed in the storage medium, computer program and computer program product embodiments of the present application, please refer to the description of the method embodiments of the present application.

[0184] It should be understood that the "one embodiment" or "an embodiment" mentioned throughout the specification means that the specific features, structures or characteristics related to the embodiment are included in at least one embodiment of the present application. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. In addition, these specific features, structures or characteristics can be combined in one or more embodiments in any suitable manner. It should be understood that the size of the sequence number of each step / process in various embodiments of the present application does not mean the order of execution, and the execution order of each step / process should be determined by its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application. The sequence number of the above embodiments of the present application is only for description, not representing the advantages and disadvantages of the embodiments.

[0185] It should be noted that in this paper, the term "include", "contain" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or includes elements inherent to such process, method, article or device. Without more limitations, the element defined by the sentence "including a…" does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0186] In several embodiments provided by the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. The above-described device embodiments are only schematic, for example, the division of units is only a logical function division, and actual implementation can have another division manner, such as: multiple units or components can be combined, or can be integrated into another system, or some features can be ignored, or not executed. In addition, the coupling or direct coupling or communication connection between the various components shown or discussed can be indirect coupling or communication connection through some interface, device or unit, which can be electrical, mechanical or other forms.

[0187] The units described as separate components above can or can not be physically separate, and the components displayed as units can or can not be physical units; they can be located in one place or distributed on multiple network units; and part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment.

[0188] In addition, each functional unit in each embodiment of the present application can be integrated into one processing unit, or each unit can be a separate unit, or two or more units can be integrated into one unit; the integrated unit can be realized in the form of hardware or in the form of hardware plus software functional unit.

[0189] Those skilled in the art can understand that all or part of the steps of the above method embodiments can be completed by program instruction related hardware, and the above program can be stored in a computer readable storage medium, and the program executes the steps including the above method embodiments when executed; and the above storage medium includes mobile storage equipment, read only memory (Read Only Memory, ROM), magnetic disc or optical disc and various storage program codes.

[0190] Alternatively, the integrated units of the present application, if implemented in the form of software functional modules and sold or used as independent products, can also be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application can be embodied in the form of software products, and the computer software products are stored in a storage medium, including a number of instructions to make a computer device (which can be a personal computer, a server, or a network device, etc.) execute all or part of the embodiments of the present application. The above storage medium includes mobile storage equipment, ROM, magnetic disc or optical disc and various storage program codes.

[0191] The above is only an embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed in the present application, which should be covered within the protection scope of the present application.

Claims

1. A maximum power point tracking method, characterized in that, The method includes: Obtain the first current-voltage curve of the photovoltaic module obtained by forward scanning, and the second current-voltage curve obtained by reverse scanning; Based on the first current-voltage curve and the second current-voltage curve, multiple voltage ranges are determined; Determine the key parameters of the maximum power point tracking algorithm corresponding to each voltage range; the key parameters include at least one or more of the following: disturbance compensation, power threshold, and waiting time; the waiting time is the waiting time for the maximum power point tracking algorithm to acquire power after disturbing the photovoltaic module; The maximum output power of the photovoltaic module is determined based on the key parameters corresponding to each voltage range and the maximum power point tracking algorithm.

2. The method based on claim 1, characterized in that, The determination of multiple voltage ranges based on the first current-voltage curve and the second current-voltage curve includes: The first current-voltage curve and the second current-voltage curve are divided into multiple voltage ranges; wherein, for the same voltage range, the voltage range corresponding to the first current-voltage curve and the voltage range corresponding to the second current-voltage curve are the same.

3. The method based on claim 2, characterized in that, The step of dividing the first current-voltage curve and the second current-voltage curve into multiple voltage intervals includes: Multiple first currents corresponding to the first current-voltage curve and multiple second currents corresponding to the second current-voltage curve are obtained at preset voltage intervals. Determine the current difference between the first current and the second current under the same voltage; Based on the relationship between the multiple current differences and at least one preset first difference threshold, the first current-voltage curve and the second current-voltage curve are respectively divided into multiple voltage intervals.

4. The method according to claim 1, characterized in that, The determination of multiple voltage ranges based on the first current-voltage curve and the second current-voltage curve includes: Determine the first power voltage curve corresponding to the first current-voltage curve, and the second power voltage curve corresponding to the second current-voltage curve; The first power voltage curve and the second power voltage curve are divided into multiple voltage ranges; wherein, for the same voltage range, the voltage range corresponding to the first power voltage curve and the voltage range corresponding to the second power voltage curve are the same.

5. The method according to claim 4, characterized in that, The step of dividing the first power voltage curve and the second power voltage curve into multiple voltage intervals includes: Multiple first powers corresponding to the first power voltage curve and multiple second powers corresponding to the second power voltage curve are obtained at preset voltage intervals. Determine the power difference between the first power and the second power under the same voltage; Based on the relationship between the power differences and at least one preset second difference threshold, the first power voltage curve and the second power voltage curve are respectively divided into multiple voltage intervals.

6. The method according to any one of claims 1 to 5, characterized in that, The method includes: The first current-voltage curve and the second current-voltage curve are respectively divided into multiple first voltage intervals; The first power voltage curve and the second power voltage curve are respectively divided into multiple second voltage intervals; A range operation is performed on the plurality of first voltage ranges and the plurality of second voltage ranges to determine a plurality of voltage ranges.

7. The method according to any one of claims 1 to 5, characterized in that, The key parameters for determining the maximum power point tracking algorithm corresponding to each voltage range include: When the maximum power point tracking algorithm is a single algorithm, the key parameters of the maximum power point tracking algorithm for each voltage range are determined. When there are multiple maximum power point tracking algorithms, determine the maximum power point tracking algorithm corresponding to each voltage range, and determine the key parameters corresponding to the maximum power point tracking algorithm.

8. The method according to any one of claims 1 to 5, characterized in that, The acquisition of the first current-voltage curve obtained by forward scanning of the photovoltaic module and the second current-voltage curve obtained by reverse scanning include: The inverter connected to the photovoltaic module receives a first voltage and a first current measured during the forward scan, and a second voltage and a second current measured during the reverse scan. Based on the first voltage and the first current, determine the first current-voltage curve; Based on the second voltage and the second current, a second current-voltage curve is determined.

9. A photovoltaic system, characterized in that, The photovoltaic system includes photovoltaic modules and an inverter; the inverter includes a control module and a detection module; wherein... The inverter is connected to the photovoltaic module. The detection module is used to perform forward and reverse scanning of the photovoltaic module at a preset frequency, and output the first voltage and first current measured by the photovoltaic module during the forward scanning process, and the second voltage and second current measured during the reverse scanning process to the control module. The control module is used to acquire a first current-voltage curve obtained by forward scanning of the photovoltaic module and a second current-voltage curve obtained by reverse scanning; determine multiple voltage ranges based on the first and second current-voltage curves; determine key parameters of the maximum power point tracking algorithm corresponding to each voltage range; the key parameters include at least one or more of the following: disturbance compensation, power threshold, and waiting time; the waiting time is the waiting time for the maximum power point tracking algorithm to acquire power after disturbing the photovoltaic module; and determine the maximum output power of the photovoltaic module based on the key parameters corresponding to each voltage range and the maximum power point tracking algorithm.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the photovoltaic system, it implements the steps of the method described in any one of claims 1 to 8.

11. A computer program product, comprising a computer program or instructions, characterized in that, When the computer program or instructions are executed by the photovoltaic system, they implement the steps of the method described in any one of claims 1 to 8.

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