Control method based on inverter, inverter and photovoltaic equipment

Abstract

The invention discloses a control method based on an inverter, the inverter and photovoltaic equipment. The method comprises the following steps: performing first curve scanning processing on the photovoltaic module to obtain power points corresponding to at least three working voltages of the photovoltaic module; determining a first voltage range according to the at least three power points; and in the first voltage range, performing disturbance processing on the working voltage of the photovoltaic module to obtain a first power point. First curve scanning processing is performed on a photovoltaic module, a plurality of power points are acquired, so that an approximate voltage interval where the maximum power point is located is quickly locked, and then disturbance processing is performed on working voltage of the photovoltaic module in the locked voltage interval to determine a first power point meeting the requirement of the maximum power point. The process of repeated adjustment in the whole voltage interval of the photovoltaic module is avoided, the adjustment times and time required for approaching the maximum power point are greatly reduced, and the speed of tracking the maximum power point is improved.

Description

Technical Field

[0001] This application relates to the field of photovoltaic technology, and in particular to a control method based on an inverter, an inverter, and photovoltaic equipment. Background Technology

[0002] An inverter is a device used to convert direct current (DC) to alternating current (AC). In photovoltaic (PV) power generation systems, an inverter refers to a PV inverter with MPPT (Maximum Power Point Tracking) functionality. MPPT controls the PV modules in the system to operate near their maximum power point, thereby maximizing the output power of the PV modules.

[0003] In related technologies, the incremental conductance method is usually used to implement the MPPT function. The incremental conductance method determines whether the current power point is on the left or right side of the PU characteristic curve of the photovoltaic module by comparing the sign relationship between the instantaneous conductance (I / V) and the change in conductance (dI / dV) in real time. This determines which direction the voltage should be adjusted in the next step, and finally approaches the point where dP / dV = 0, which is then taken as the maximum power point.

[0004] However, the incremental conductance method is slow in tracking the maximum power point. Summary of the Invention

[0005] This application provides a control method based on an inverter, an inverter, and photovoltaic equipment. The technical solution is as follows:

[0006] On the one hand, a control method based on an inverter is provided, wherein the inverter is connected to a photovoltaic module; the method includes:

[0007] The photovoltaic module is subjected to a first curve scanning process to obtain power points corresponding to at least three operating voltages of the photovoltaic module, wherein the power points indicate the output power of the photovoltaic module at the corresponding operating voltage; the first curve scanning process is used to control the operating voltage of the photovoltaic module to be gradually increased based on a first scanning step size;

[0008] A first voltage range is determined based on at least three power points, wherein the power change trend corresponding to the power points within the first voltage range is first increasing and then decreasing.

[0009] Within the first voltage range, the operating voltage of the photovoltaic module is perturbed to obtain a first power point, which meets the maximum power point requirement of the photovoltaic module.

[0010] The photovoltaic module is controlled to operate based on the first operating voltage corresponding to the first power point.

[0011] On the other hand, an inverter-based control device is provided, the device comprising:

[0012] A first control module is configured to perform a first curve scanning process on the photovoltaic module to obtain power points corresponding to at least three operating voltages of the photovoltaic module, wherein the power points indicate the output power of the photovoltaic module at the corresponding operating voltage; the first curve scanning process is configured to control the operating voltage of the photovoltaic module to be gradually increased based on a first scanning step size.

[0013] The first control module is configured to determine a first voltage range based on at least three power points, wherein the power change trend corresponding to the power points within the first voltage range is first increasing and then decreasing;

[0014] The second control module is used to perform perturbation processing on the operating voltage of the photovoltaic module within the first voltage range to obtain a first power point, wherein the first power point meets the maximum power point requirement corresponding to the photovoltaic module;

[0015] The second control module is used to control the operation of the photovoltaic module based on the first operating voltage corresponding to the first power point.

[0016] On the other hand, a controller is provided, the controller including a processor and a memory, the memory storing at least one program, the at least one program being loaded and executed by the processor to implement any of the inverter-based control methods described above.

[0017] On the other hand, an inverter is provided, the inverter including any of the controllers described above, the controller being used to execute any of the inverter-based control methods described above; the inverter includes a photovoltaic inverter.

[0018] On the other hand, a photovoltaic device is provided, the photovoltaic device comprising at least one set of interconnected inverters and photovoltaic modules; the inverter is any of the inverters described above.

[0019] On the other hand, a photovoltaic power generation system is provided, the photovoltaic power generation system including at least one photovoltaic device; the photovoltaic device is any of the photovoltaic devices described above.

[0020] The beneficial effects of the technical solutions provided in this application include at least the following:

[0021] By performing a first curve scan on the photovoltaic module and collecting multiple power points, the approximate voltage range (i.e., the first voltage range) where the maximum power point is located can be quickly identified. Then, within the identified voltage range, the operating voltage of the photovoltaic module is perturbed to determine the first power point that meets the requirements of the maximum power point. Finally, the photovoltaic module is controlled to operate at the first operating voltage corresponding to the first power point. Since the perturbation is only performed within the identified small voltage range, the process of repeatedly adjusting within the entire voltage range of the photovoltaic module is avoided. This significantly reduces the number of adjustments and the time required to approach the maximum power point, improves the speed of tracking the maximum power point, and thus enhances the power generation efficiency of the photovoltaic power generation system. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a structural block diagram of an inverter system provided in an exemplary embodiment of this application;

[0024] Figure 2 This is a schematic diagram of the PU characteristic curve of a photovoltaic module provided in an exemplary embodiment of this application;

[0025] Figure 3 This is a flowchart of an inverter-based control method provided in an exemplary embodiment of this application;

[0026] Figure 4 This is a schematic diagram of a first curve scanning process provided in an exemplary embodiment of this application;

[0027] Figure 5 This is a schematic diagram of a first curve scanning process provided in another exemplary embodiment of this application;

[0028] Figure 6 This is a flowchart of an inverter-based control method provided in another exemplary embodiment of this application;

[0029] Figure 7 This is a schematic diagram of the PU characteristic curve of a photovoltaic module provided in another exemplary embodiment of this application;

[0030] Figure 8 This is a flowchart of an inverter-based control method provided in yet another exemplary embodiment of this application;

[0031] Figure 9This is a schematic diagram of the state transition of a maximum power point tracking (MPPT) processing task provided in an exemplary embodiment of this application;

[0032] Figure 10 This is a flowchart of a maximum power point tracking (MPPT) processing task provided in an exemplary embodiment of this application;

[0033] Figure 11 This is a flowchart of a first curve scanning process provided in an exemplary embodiment of this application;

[0034] Figure 12 This is a flowchart illustrating a temporary state provided in an exemplary embodiment of this application;

[0035] Figure 13 This is a flowchart of a perturbation process provided in an exemplary embodiment of this application;

[0036] Figure 14 This is a schematic diagram of a disturbance processing procedure provided in an exemplary embodiment of this application;

[0037] Figure 15 This is a schematic diagram of a disturbance processing procedure provided in another exemplary embodiment of this application;

[0038] Figure 16 This is a schematic diagram of a disturbance processing procedure provided in yet another exemplary embodiment of this application;

[0039] Figure 17 This is a flowchart of a second curve scanning process provided in an exemplary embodiment of this application;

[0040] Figure 18 This is a schematic diagram of the Boost control process of a photovoltaic module provided in an exemplary embodiment of this application;

[0041] Figure 19 This is a structural block diagram of an inverter-based control device provided in an exemplary embodiment of this application;

[0042] Figure 20 This is a structural block diagram of a controller provided in an exemplary embodiment of this application;

[0043] Figure 21 This is a structural block diagram of an inverter provided in an exemplary embodiment of this application;

[0044] Figure 22 This is a structural block diagram of a photovoltaic device provided in an exemplary embodiment of this application;

[0045] Figure 23 This is a structural block diagram of a photovoltaic power generation system provided in an exemplary embodiment of this application. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0047] In this application, the terms "first" and "second" are used to distinguish between identical or similar items that have essentially the same function. It should be understood that there is no logical or temporal dependency between "first" and "second", nor is there any limitation on the quantity or execution order.

[0048] First, the inverter system that implements the inverter-based control method provided in this application will be introduced.

[0049] Please refer to Figure 1 The diagram illustrates a structural block diagram of an inverter system. The inverter system 100 includes: an inverter 110, PV (Photovoltaic) port 121 and PV2 port 122, a battery management system (BMS) 131 and a battery 132, an electricity meter 140, a power grid 150, a Wi-Fi (Wireless Fidelity) communication stick 161, and an energy management system (EMS) 162.

[0050] Inverter 110 connects to photovoltaic modules via PV ports ( Figure 1 (Not shown) Connection. The PV port includes... Figure 1 Regarding the PV1 port 121 and PV2 port 122 shown, it should be noted that... Figure 1 This explanation uses only two PV ports as an example. Depending on actual needs, the inverter system can contain more or fewer PV ports; this is not limited here. Optionally, each PV port connects to one or more photovoltaic modules. Optionally, the inverter 110 can be implemented as a Power Conversion System (PSC). The PSC is used to achieve bidirectional conversion of electrical energy between AC and DC, such as converting DC power generated by the photovoltaic modules or DC power released by battery 132 into AC power, and converting AC power from the grid 150 into DC power to charge battery 132.

[0051] Optionally, the photovoltaic module includes a solar panel. The solar panel is used to convert solar energy into direct current (DC), and then introduce the DC into the inverter system 100, such as storing the DC in battery 132, and / or converting the DC into alternating current (AC) by inverter 110 and supplying it to the load.

[0052] Optionally, battery 132 includes a lithium battery pack. Battery 132 is used to store excess electrical energy generated by the photovoltaic modules or electrical energy generated during off-peak hours of the grid 150, and release it when needed. Illustratively, when the photovoltaic modules generate a large amount of power, a portion of the electrical energy is converted by inverter 110 and supplied to the load. Figure 1 (Not shown), the remaining energy is stored in battery 132. When the photovoltaic module's power generation is low, the electrical energy stored in battery 132 is converted by inverter 110 and supplied to the load. Also, during off-peak hours when the grid 150 has lower electricity prices, battery 132 obtains electrical energy from the grid 150 through inverter 110 (i.e., charges from the grid 150); during peak hours when the grid 150 has higher electricity prices, the electrical energy stored in battery 132 is converted by inverter 110 and supplied to the load, thereby reducing the power consumption of the grid 150 during peak hours. Additionally, battery 132 can also supply power to the load through inverter 110 when the grid 150 experiences a power outage. Battery management system 131 monitors the voltage, current, temperature, and other states of battery 132 to ensure battery safety (preventing overcharging, over-discharging, and overheating) and optimize battery life.

[0053] The power grid 150 is a public power network. The alternating current generated by the power grid 150 can be directly supplied to the load, or it can be converted into direct current by the inverter 110 to charge the battery 132. In some embodiments, when the battery 132 is fully charged and the photovoltaic modules generate excess power, the excess power can be fed back to the power grid 150. The meter 160 is used to measure the electrical energy interaction between the inverter system 100 and the load and the power grid (such as obtaining power from the grid and supplying power to the grid).

[0054] The WIFI communication stick 161 connects to the inverter 110 to enable the inverter system 100 to network with the cloud 170. Users can remotely view the operating status of the inverter system 100 (such as real-time power generation, power consumption, battery status, etc.) through application clients installed on terminals (such as mobile phones, computers, etc.), and can also remotely set operating strategies (such as setting charging time periods). The energy management system 162 is used to intelligently dispatch energy based on photovoltaic output, battery status, power demand, and control commands from the application client (such as prioritizing photovoltaic power and storing surplus power in the battery).

[0055] In some embodiments, the inverter system 100 can be implemented as a home energy storage inverter system. In a home energy storage inverter system, the load can be implemented as household electrical appliances, such as televisions, refrigerators, air conditioners, etc.

[0056] In some embodiments, the inverter 110 includes at least: 1) a DC / AC inverter circuit responsible for converting direct current to alternating current; and 2) a controller for running control algorithms, such as the inverter-based control method provided in this application. Optionally, if the inverter 110 is implemented as an energy storage inverter, the inverter 110 further includes an AC / DC rectifier circuit responsible for converting alternating current to direct current.

[0057] Optionally, the controller includes an MPPT controller, which implements the MPPT function using the inverter-based control method provided in this application. The MPPT function controls the photovoltaic module to operate near its maximum power point, thereby maximizing the output power.

[0058] Regarding the maximum power point: the output power of a photovoltaic module is closely related to light intensity, temperature, and load impedance. Its output power (P) - operating voltage (U) characteristic curve is as follows: Figure 2 As shown, by Figure 2 It is known that the PU characteristic curve 200 of a photovoltaic module has a maximum power point (MPP), but this point will shift with environmental changes. For example, in the morning when sunlight is weak, the operating voltage corresponding to the MPP may be 30V; at noon when sunlight is strong, the operating voltage corresponding to the MPP may be 35V. Therefore, it is necessary to dynamically adjust the operating voltage of the photovoltaic module through a controller so that the photovoltaic module operates near the maximum power point.

[0059] The flow of the inverter-based control method provided in this application is described below.

[0060] Based on the above introduction, Figure 3 This is a flowchart of an inverter-based control method provided in an embodiment of this application, which is applied to, for example... Figure 1 The following explanation uses an inverter (specifically, a controller within the inverter) as an example, where the inverter is connected to photovoltaic modules. The method includes steps 310 to 340.

[0061] Step 310: Perform a first curve scan on the photovoltaic module to obtain the power points corresponding to at least three operating voltages of the photovoltaic module.

[0062] The power point indicates the output power of a photovoltaic module at the corresponding operating voltage.

[0063] The first curve scanning process is used to control the operating voltage of the photovoltaic module to be gradually increased based on the first scanning step size.

[0064] The following explanation uses the i-th and (i+1)-th operating voltages as examples to illustrate the first curve scanning process provided in this application. i is a positive integer.

[0065] Step 1 Obtain the i-th operating voltage; control the operation of the photovoltaic module based on the i-th operating voltage to obtain the i-th power point.

[0066] Step 2 Perform the i-th voltage boost operation on the i-th operating voltage to obtain the (i+1)-th operating voltage; control the operation of the photovoltaic module based on the (i+1)-th operating voltage to obtain the (i+1)-th power point.

[0067] The boost voltage corresponding to the i-th voltage boost operation is determined by the reference voltage corresponding to the first scan step size.

[0068] The (i+1)th working voltage is the sum of the ith working voltage and the boost voltage corresponding to the ith voltage boost operation.

[0069] Optionally, if i = 1, then the first working voltage is the reference voltage corresponding to the first scan step, denoted as V.

[0070] In the above embodiments, a progressive voltage adjustment curve scanning process is defined. By gradually increasing the operating voltage, blind disturbances are avoided, thus improving efficiency. The voltage increase operation is determined by the reference voltage corresponding to the first scanning step size, ensuring the uniformity of the power point data and providing reliable data support for subsequently determining the first voltage range, reducing range misjudgments caused by data clutter.

[0071] In some embodiments, the photovoltaic module has a maximum operating voltage and a minimum operating voltage. The operating voltage determined based on a first scan step size is voltage-limited based on the maximum and minimum operating voltages to obtain a limited operating voltage. The photovoltaic module is then controlled to operate based on the limited operating voltage to obtain the corresponding power point. Schematic example, taking the i-th operating voltage, voltage limiting is performed on the i-th operating voltage based on the maximum and minimum operating voltages to obtain the limited i-th operating voltage. The photovoltaic module is then controlled to operate based on the limited i-th operating voltage to obtain the corresponding power point. Specifically, when the calculated i-th operating voltage is less than the minimum operating voltage, the minimum operating voltage is used as the processed i-th operating voltage; when the calculated i-th operating voltage is greater than the maximum operating voltage, the maximum operating voltage is used as the processed i-th operating voltage.

[0072] The method for gradually increasing the operating voltage of a photovoltaic module based on a first scan step size includes at least one of the following:

[0073] Method 1: Based on the same first scan step size, control the operating voltage of the photovoltaic module to be gradually increased.

[0074] Optionally, the boost voltage corresponding to the (i+1)th voltage boost operation is equal to the boost voltage corresponding to the ith voltage boost operation. For illustration, if the first operating voltage is the reference voltage V corresponding to the first scan step size, then the second operating voltage is 2V, the third operating voltage is 3V, and so on; these details will not be elaborated here.

[0075] Method 2: By gradually increasing the first scan step size, the operating voltage of the photovoltaic module is controlled to gradually increase.

[0076] Optionally, the boost voltage corresponding to the (i+1)th voltage boost operation = N × the boost voltage corresponding to the ith voltage boost operation, where N is an integer greater than 1. For illustration, taking N=2 as an example, if the first working voltage is the reference voltage V corresponding to the first scan step, then the second working voltage is V+V=2V, the third working voltage is 2V+2V=4V, etc.; or the second working voltage is V+2V=3V, the third working voltage is 3V+4V=7V, etc., which will not be elaborated here.

[0077] Optionally, the voltage boosting operation corresponds to a maximum boosting voltage. If the boosting voltage calculated based on "N × boosting voltage corresponding to the i-th voltage boosting operation" is greater than or equal to the maximum boosting voltage, then the boosting voltage corresponding to the (i+1)-th voltage boosting operation is equal to the maximum boosting voltage.

[0078] It should be noted that the above example of the method for gradually increasing the operating voltage of a photovoltaic module based on the first scan step size is merely illustrative and is not intended to limit the scope of this application.

[0079] In some embodiments, performing the i-th voltage boost operation on the i-th operating voltage to obtain the (i+1)-th operating voltage includes: acquiring one or more operating parameters of the photovoltaic module under current environmental conditions; the operating parameters include at least one of the following: ambient temperature, irradiance, and the current open-circuit voltage of the photovoltaic module; determining a first scan step size based on the one or more operating parameters; and performing the i-th voltage boost operation on the i-th operating voltage based on a dynamic reference voltage. A dynamic adaptive adjustment of the scan step size is introduced, enabling optimization of the scanning process based on real-time environmental conditions (such as temperature and irradiance). Using a smaller step size under low irradiance can improve scanning accuracy, while using a larger step size under high irradiance can accelerate scanning speed, thereby achieving an intelligent balance between accuracy and efficiency and improving the adaptability and performance of MPPT.

[0080] In some embodiments, the first scan step size is dynamically adjusted based on the real-time power change rate of the photovoltaic module; wherein: when the absolute value of the power change rate of two adjacent power points is greater than a preset change threshold, the first scan step size is reduced; when the absolute value of the power change rate of two adjacent power points is less than or equal to the preset change threshold, the first scan step size is increased.

[0081] In some embodiments, a first curve scan process is performed on the photovoltaic module; if the photovoltaic module meets the first scan completion condition, the first curve scan process is stopped, and the power points corresponding to at least three operating voltages of the photovoltaic module are obtained.

[0082] Optionally, the conditions for completing the first scan include at least one of the following:

[0083] (1) The current operating voltage of the photovoltaic module is less than the minimum operating voltage of the photovoltaic module.

[0084] (2) The current operating current of the photovoltaic module is greater than the maximum operating current of the photovoltaic module.

[0085] (3) The operating voltage setting is less than the minimum operating voltage of the photovoltaic module. That is, the operating voltage that the controller will set for the photovoltaic module in the next step is less than the minimum operating voltage of the photovoltaic module.

[0086] (4) The output power of the photovoltaic module is greater than the maximum output power (such as the rated power) of the photovoltaic module.

[0087] (5) The DC bus voltage is greater than the maximum bus voltage. The maximum bus voltage refers to the highest voltage threshold set for the bus.

[0088] (6) The output power corresponding to the current operating voltage of the photovoltaic module is less than the output power corresponding to the previous operating voltage of the photovoltaic module. For illustration, during the first curve scanning process, if the current output power of the photovoltaic module is less than the previous output power of the photovoltaic module, it indicates that the maximum power point has been passed. Therefore, the first curve scanning process can be stopped, and all scanned power points can be recorded as at least three power points.

[0089] Among them, the first scan completion conditions (1)-(5) can be regarded as a safety protection mechanism for photovoltaic modules. The purpose is to stop the first curve scan process during the first curve scan process when the photovoltaic module is in an abnormal operating state or exceeds the safe range to prevent equipment damage.

[0090] In some embodiments, the first curve scanning process further includes: recording the output current corresponding to each operating voltage point; plotting and analyzing the real-time current-voltage curve; if the current-voltage curve shows multiple steps or abnormal steep drops, it is determined that there is a local shadow or fault in the photovoltaic module, and a fault alarm is generated.

[0091] In some embodiments, the first curve scanning process is a bidirectional scan. Optionally, performing the first curve scanning process on the photovoltaic module includes: controlling the operating voltage of the photovoltaic module to gradually increase from the starting voltage to the first voltage threshold with a first scan step size, completing the first unidirectional scan, and recording the first set of power points; controlling the operating voltage of the photovoltaic module to gradually decrease from the first voltage threshold to the second voltage threshold with a third scan step size, completing the second unidirectional scan, and recording the second set of power points; wherein, the power points corresponding to at least three operating voltages are determined by the first set of power points and the second set of power points; the first scan step size and the third scan step size may be the same or different.

[0092] In some embodiments, before performing the first curve scanning process on the photovoltaic module, the method further includes: triggering the first curve scanning process in response to detecting that the output power change rate of the photovoltaic module has continuously exceeded a power change threshold for a preset duration; setting a scan start voltage based on the historical optimal operating voltage, wherein the scan start voltage is lower than the historical optimal operating voltage; and performing the first curve scanning process starting from the scan start voltage. This embodiment only starts when a significant change in illumination is detected, saving energy and reducing unnecessary operations. Starting the scan from a point slightly lower than the historical optimal voltage allows for rapid approximation of the MPP region under the current environment, greatly improving the efficiency of the scanning process.

[0093] In some embodiments, during the execution of the first curve scanning process, the output power fluctuation value of the photovoltaic module is monitored in real time; when the output power fluctuation value exceeds the fluctuation threshold for a preset number of consecutive times, the first curve scanning process is paused and the current scanning position is recorded; after the output power fluctuation value is less than or equal to the fluctuation threshold and continues for a preset duration, the first curve scanning process is continued from the current scanning position, and the first scanning step size is temporarily reduced to M% of the original step size, where M is less than 100.

[0094] Step 320: Determine the first voltage range based on at least three power points.

[0095] The power change trend corresponding to the power point within the first voltage range is first increasing and then decreasing. That is, the first voltage range is the voltage range that includes the maximum power point.

[0096] Optionally, the last of at least three power points is set as the first target power point. The first target power point is the power point corresponding to the current operation of the photovoltaic module. Schematic, the first target power point corresponds to the first target operating voltage and the first target output power, that is, the current operating voltage of the photovoltaic module is the first target operating voltage, and the current output power is the first target output power.

[0097] In some embodiments, determining the first voltage range based on at least three power points includes at least one of the following:

[0098] Scenario 1 The power change trend corresponding to at least three power points shows an increase followed by a decrease, indicating that the maximum power point is included within at least three power points. The first voltage range is determined within the voltage range corresponding to at least three power points.

[0099] In some embodiments, at least three power points are traversed from back to front. The first power point whose output power is less than or equal to the first target output power is taken as the second target power point. The second target power point corresponds to the second target operating voltage and the second target output power. Then, the voltage range between the second target operating voltage and the first target operating voltage is the first voltage range. For illustration, please refer to [reference needed]. Figure 4 When the first curve scanning process stops, the last power point is point c. Assuming that the voltage corresponding to point c is Vc, the range B between V0 and Vc can be determined as the first voltage range.

[0100] In other embodiments, the voltage range corresponding to at least three power points is directly set as the first voltage range.

[0101] Optionally, when performing perturbation processing in step 330, the first target working voltage is set as the "first working voltage" as described below. Then, the first perturbation direction corresponding to the first target working voltage is the negative direction, and the first perturbation step size corresponding to the first target working voltage can be set as the first preset perturbation step size, such as 10.

[0102] Scenario 2 If the power change trend of at least three power points shows a monotonically increasing trend, it means that at least three power points are all located to the left of the maximum power point. This determines that the first voltage range is to the right of the voltage range corresponding to at least three power points. In other words, the operating voltage corresponding to the maximum power point among the at least three power points is less than or equal to the minimum voltage corresponding to the first voltage range.

[0103] In some embodiments, the voltage range between the first target operating voltage and the second preset voltage is used as the first voltage range. Optionally, the second preset voltage is the open-circuit voltage of the photovoltaic module. Optionally, when performing perturbation processing in step 330, if the first target operating voltage is set as the "first operating voltage" described below, then the first perturbation direction corresponding to the first target operating voltage is the positive direction, and the first perturbation step size corresponding to the first target operating voltage can be set as the second preset perturbation step size, such as 15. The first preset perturbation step size and the second preset perturbation step size can be the same or different, which is not limited here.

[0104] In other embodiments, the voltage range between the first target operating voltage and the first disturbance voltage is used as the first voltage range. Optionally, the first disturbance voltage is the disturbance voltage obtained after performing a preset disturbance operation on the first target operating voltage. The preset disturbance operation corresponds to a preset disturbance direction and a preset disturbance step size. The preset disturbance direction is a positive direction, and the preset disturbance step size can be the same as or different from the second preset disturbance step size mentioned above. Optionally, for a detailed description of the preset disturbance operation, please refer to the description of the disturbance operation in step 330, which will not be repeated here. Optionally, when performing disturbance processing in step 330, if the first disturbance voltage is set to the "first operating voltage" mentioned below, then the first disturbance direction corresponding to the first disturbance voltage is a negative direction, and the first disturbance step size can be set to a third preset disturbance step size, such as 10. The third preset disturbance step size and the first preset disturbance step size can be the same as or different, which is not limited here. For illustration, please refer to Figure 5 When the first curve scanning process stops, the last power is point d. Assuming that the voltage corresponding to point d is Vd, the range D to the right of Vd can be determined as the first voltage range.

[0105] In the above embodiments, two possible scenarios in the first curve scanning process are handled separately. If the trend is monotonically increasing, it indicates that the MPP is at a higher voltage. In this case, perturbation processing is performed in the higher voltage range to ensure that the MPP is not missed. If the trend first increases and then decreases, the voltage range containing the MPP has been successfully found. In this case, perturbation is performed within the locked voltage range to improve the overall search efficiency.

[0106] The embodiments in this application are mainly illustrated using the above-described case one as an example.

[0107] In some embodiments, after obtaining at least three power points, noise filtering is performed on the power points. The noise filtering process includes: calculating the deviation between the power value of each power point and the average power value of two adjacent power points; if the deviation is greater than a deviation threshold, the power point is discarded, and a new power point is added based on linear interpolation. Based on the processed power points, the step of determining a first voltage range is performed.

[0108] Step 330: Within the first voltage range, perform perturbation processing on the operating voltage of the photovoltaic module to obtain the first power point.

[0109] The first power point meets the maximum power point requirement corresponding to the photovoltaic module. The perturbation process includes at least two perturbation operations; the maximum power point requirement includes at least one of the following:

[0110] (1) After N consecutive perturbation operations, the absolute value of the power difference between the current output power of the photovoltaic module and the previous output power of the photovoltaic module is less than the first power threshold; N is an integer greater than 1. Optionally, the first power threshold can be set to 0 or a value greater than 0.

[0111] (2) After N consecutive disturbance operations, the absolute value of the voltage difference between the current operating voltage of the photovoltaic module and the previous operating voltage of the photovoltaic module is less than a first voltage threshold. Optionally, the first voltage threshold can be set to 0 or a value greater than 0.

[0112] In some embodiments, after N consecutive perturbation operations, if the absolute value of the power difference between the current output power of the photovoltaic module and the previous output power of the photovoltaic module is less than a first power threshold, and the absolute value of the voltage difference between the current operating voltage of the photovoltaic module and the previous operating voltage of the photovoltaic module is less than a first voltage threshold, the power point corresponding to the current operating voltage of the photovoltaic module is taken as the first power point.

[0113] Optionally, after N consecutive perturbation operations, if the current output power of the photovoltaic module is equal to the previous output power of the photovoltaic module, and the current operating voltage of the photovoltaic module is equal to the voltage difference between the previous operating voltage of the photovoltaic module, the power point corresponding to the current operating voltage of the photovoltaic module is taken as the first power point.

[0114] The above scheme clearly defines the maximum power point requirement, avoiding infinite loops or premature termination of the disturbance process. The use of a criterion that shows very small changes over N consecutive cycles improves anti-interference capabilities, prevents misjudgments of finding the MPP due to transient noise or fluctuations, and increases the stability and reliability of disturbance handling.

[0115] In some embodiments, the perturbation operation is used to adjust the operating voltage of the photovoltaic module according to the current perturbation step size and perturbation direction, and to determine the next perturbation step size and perturbation direction according to the difference between the output power of the photovoltaic module before adjustment and the output power of the photovoltaic module after adjustment.

[0116] The perturbation processing procedure provided in this application will be explained below using the j-th perturbation operation out of at least two perturbation operations as an example. j is a positive integer.

[0117] Step 1 Based on the j-th perturbation direction and the j-th perturbation step size, perform the j-th perturbation operation on the j-th operating voltage of the photovoltaic module to obtain the (j+1)-th operating voltage; control the operation of the photovoltaic module based on the (j+1)-th operating voltage to obtain the (j+1)-th output power.

[0118] Optionally, when the j-th disturbance direction is positive, the reference voltage corresponding to the j-th disturbance step is added to the j-th operating voltage to obtain the (j+1)-th operating voltage. When the j-th disturbance direction is negative, the reference voltage corresponding to the j-th disturbance step is subtracted from the j-th operating voltage to obtain the (j+1)-th operating voltage.

[0119] Optionally, when j=1, that is, when the j-th working voltage is the first working voltage, the first working voltage can be the working voltage of the photovoltaic module when the first curve scanning process stops, such as the first target working voltage or the first disturbance voltage mentioned above. The first disturbance direction and the first disturbance step size corresponding to the first working voltage have been explained in step 320 above, and will not be repeated here.

[0120] Optionally, when j > 1, the steps for determining the j-th disturbance direction and j-th disturbance step size corresponding to the j-th operating voltage are as follows: Based on the difference between the j-th output power and the (j-1)-th output power, determine the j-th disturbance direction and j-th disturbance step size. The explanation of this step can be found in step 2 above, and will not be repeated here.

[0121] Step 2. If the (j+1)th output power meets the maximum power point requirement, the (j+1)th output power is taken as the first power point.

[0122] Step 3 If the (j+1)th output power does not meet the maximum power point requirement, the (j+1)th perturbation direction and the (j+1)th perturbation step size are determined based on the difference between the (j+1)th output power and the jth output power. Based on the (j+1)th perturbation direction and the (j+1)th perturbation step size, perturbation processing is continued to obtain the first power point.

[0123] The above scheme refines the perturbation process. If the power increases, the perturbation continues in the same direction; if the power decreases, the perturbation is carried out in the opposite direction to achieve automatic approximation of MPP.

[0124] In some embodiments, the (j+1)th perturbation value is determined based on a first power difference between the (j+1)th output power and the jth output power.

[0125] Optionally, if the (j+1)th disturbance value is greater than or equal to the first preset value (e.g., 0), the (j+1)th disturbance direction is determined to be positive; if the (j+1)th disturbance value is less than the first preset value, the (j+1)th disturbance direction is determined to be negative.

[0126] Optionally, the perturbation step size is the same for each perturbation operation, which can be set to a preset perturbation step size, i.e., the (j+1)th perturbation step size is the preset perturbation step size. Alternatively, the (j+1)th perturbation step size can be determined based on the perturbation coefficient and the (j+1)th perturbation value; illustratively, the perturbation coefficient is represented by k, where k > 0 and k is a preset system value, such as k being set to 0.16. Optionally, k is associated with the power level, and different power levels correspond to different k, which is not limited here.

[0127] Optionally, obtain the first voltage difference between the (j+1)th operating voltage and the jth operating voltage; determine the first ratio between the (j+1)th disturbance value and the first voltage difference; and determine the (j+1)th disturbance step size based on the disturbance coefficient and the first ratio. (Illustrative example)

[0128] In the above embodiments, the perturbation step size for the next step is determined based on the ratio of the power difference to the voltage difference. A larger ratio indicates a greater distance from the MPP, allowing for a larger step size; a smaller ratio indicates proximity to the MPP, requiring a smaller step size. This achieves adaptive optimization of the step size, accelerating the tracking process and reducing steady-state losses.

[0129] Optionally, the method for determining the (j+1)th perturbation value includes at least one of the following:

[0130] Method 1 The first power difference between the (j+1)th output power and the jth output power is defined as the (j+1)th perturbation value. Illustratively, the (j+1)th perturbation value = (j+1)th output power - jth output power.

[0131] Method 2 Calculate the first power difference between the (j+1)th output power and the jth output power; calculate the second power difference between the jth output power and the (j-1)th output power; determine the (j+1)th perturbation value based on the first power difference and the second power difference. Illustratively, the difference between the first power difference and the second power difference is calculated as the (j+1)th perturbation value, i.e., the (j+1)th perturbation value = ((j+1)th output power - jth output power) - (jth output power - (j-1)th output power).

[0132] In some embodiments, determining the (j+1)th perturbation step size further includes: establishing a perturbation step size prediction model based on the output power change rate and operating voltage change rate of the photovoltaic module; inputting the (j+1)th output power, the jth output power, the (j+1)th operating voltage, and the jth operating voltage into the perturbation step size prediction model to obtain the predicted value of the (j+1)th perturbation step size; the perturbation step size prediction model is trained using historical operating data of the photovoltaic module.

[0133] In some embodiments, the perturbation process further includes: real-time monitoring of the output power change rate of the photovoltaic module; if the output power change rate exceeds a preset threshold, determining that a sudden change in illumination conditions has occurred; interrupting the current perturbation process and restarting the first curve scan process to quickly track the new maximum power point. The starting voltage for restarting the first curve scan process is determined based on the functional relationship between the historical operating voltage data of the photovoltaic module recorded before the sudden change and the current illumination intensity.

[0134] Step 340: Control the operation of the photovoltaic module based on the first operating voltage corresponding to the first power point.

[0135] Optionally, a first operating current is determined based on a first operating voltage corresponding to a first power point; a first control signal is determined based on the first operating current, the first control signal being used to control the duty cycle of the Boost circuit corresponding to the photovoltaic module, thereby changing the impedance of the photovoltaic module to control its operating voltage and operating current; based on the first control signal, the photovoltaic module is controlled to operate at the first operating voltage and the first operating current. Illustratively, the Boost circuit adjusts the impedance at its input terminal by controlling the duty cycle of its switching transistor, thereby determining the magnitude of the current drawn from the photovoltaic module, ultimately stabilizing the terminal voltage of the photovoltaic module. The first control signal can be implemented as a duty cycle adjustment signal required to control the Boost switching transistor, such as a pulse width modulation (PWM) control waveform. When the Boost circuit duty cycle increases, the switching transistor's on-time becomes longer, the inductor's energy storage increases, and the Boost circuit draws more current from the photovoltaic module, causing the photovoltaic module's operating voltage to decrease. Conversely, when the Boost circuit duty cycle decreases, the current drawn from the photovoltaic module decreases, and its operating voltage increases.

[0136] In summary, the inverter-based control method provided in this application quickly locks down the approximate voltage range (i.e., the first voltage range) where the maximum power point is located by performing a first curve scan on the photovoltaic module and collecting multiple power points. Then, within the locked voltage range, the operating voltage of the photovoltaic module is perturbed to determine the first power point that meets the requirements of the maximum power point. Finally, the photovoltaic module is controlled to operate at the first operating voltage corresponding to the first power point. Since the perturbation is only performed within the locked small voltage range, the process of repeatedly adjusting within the entire voltage range of the photovoltaic module is avoided, significantly reducing the number of adjustments and time required to approach the maximum power point, improving the speed of tracking the maximum power point, and thus improving the power generation efficiency of the photovoltaic power generation system.

[0137] In some embodiments, after perturbation processing is performed on the operating voltage of the photovoltaic module, a second curve scan processing is also required periodically on the photovoltaic module. Figure 6 This is a flowchart of an inverter-based control method provided in an embodiment of this application, such as... Figure 6 As shown, after step 330 or step 340, the following steps 350 to 380 are also included.

[0138] Step 350: While the photovoltaic module is in the first scan cycle at the current moment, perform the second curve scan process.

[0139] The second curve scanning process is used to control the gradual increase of the photovoltaic module's operating voltage based on a second scan step size. Optionally, the operating voltage of the photovoltaic module is controlled to increase gradually based on the same second scan step size. Alternatively, the operating voltage of the photovoltaic module is controlled to increase gradually by progressively increasing the second scan step size.

[0140] The second curve scanning process may be the same as or different from the first curve scanning process. For a description of the second curve scanning process, please refer to the explanation in step 310; it will not be repeated here. The first scan step size and the second scan step size may be the same or different. Schematic, if the first scan step size corresponds to a maximum boost voltage, then the second scan step size can be set to the maximum boost voltage.

[0141] In some embodiments, the duration of the first scan cycle is adaptively set based on the historical power fluctuation data of the photovoltaic module; the historical power fluctuation data includes the power standard deviation and power change frequency within a preset time period; wherein, when the power standard deviation is greater than a preset standard deviation threshold or the power change frequency is greater than a preset frequency threshold, the first scan cycle is shortened; otherwise, the first scan cycle is extended.

[0142] In some embodiments, after stopping the first curve scanning process, the second curve scanning process is started at the start time of the first scanning cycle after a preset period of time; wherein, the preset period of time can be set to a relatively long duration, such as 30 minutes. Alternatively, the second curve scanning process is started at the start time of the first scanning cycle after a preset period of time, starting from the stop time of the disturbance processing (or the time when the photovoltaic module begins to operate at the first power point).

[0143] Step 360: Determine the second voltage range based on the power point obtained from the second curve scanning process.

[0144] The power change trend corresponding to the power point within the second voltage range is first increasing and then decreasing. That is, the second voltage range includes the voltage range containing the maximum power point. For details on determining the second voltage range, please refer to the explanation of determining the first voltage range in step 320; it will not be repeated here.

[0145] In some embodiments, when the photovoltaic module meets the second scan completion conditions, the second curve scan process is stopped, and a second voltage range is determined based on the power point obtained from the second curve scan process; the second scan completion conditions include at least one of the following:

[0146] (1) The voltage difference between the current operating voltage of the photovoltaic module and the maximum operating voltage of the photovoltaic module is greater than the first preset voltage.

[0147] Indicatively, during the first curve scanning process, when the operating voltage of the photovoltaic module is adjusted to be close to (maximum operating voltage - voltage difference), it indicates that the entire range of the PU characteristic curve of the photovoltaic module has been basically scanned, thus effectively preventing the determined first power point from being a local maximum power point and avoiding the misconception of falling into local peaks. For example... Figure 7 As shown, when the photovoltaic module's PU characteristic curve 700 contains two peak points (point a and point b) due to cloudy or rainy weather, partial shading, or other reasons, where point a is the maximum power point, the voltage range containing the maximum power point a can be determined from the PU characteristic curve 700 through the second curve scanning process using the method provided in this application, thereby accurately tracking the maximum power point.

[0148] (2) The current operating current of the photovoltaic module is greater than the product between the maximum operating current of the photovoltaic module and the first current coefficient.

[0149] (3) The current operating current of the photovoltaic module is less than the product between the minimum operating current of the photovoltaic module and the second current coefficient.

[0150] (4) The output power of the photovoltaic module is greater than the product of the maximum output power of the photovoltaic module and the power coefficient.

[0151] Step 370: Within the second voltage range, perform perturbation processing on the operating voltage of the photovoltaic module to obtain the second power point.

[0152] The second power point meets the maximum power point requirement for photovoltaic modules.

[0153] For details on the second power point, please refer to the explanation of determining the first power point in step 330; it will not be repeated here.

[0154] Step 380: Control the operation of the photovoltaic module based on the second operating voltage corresponding to the second power point.

[0155] Optionally, a second operating current is determined based on a second operating voltage corresponding to a second power point; a second control signal is determined based on the second operating current, the second control signal being used to control the duty cycle of the Boost circuit corresponding to the photovoltaic module, thereby changing the impedance of the photovoltaic module to control the operating voltage and operating current of the photovoltaic module; and the photovoltaic module is controlled to operate at the second operating voltage and the second operating current based on the second control signal.

[0156] In summary, the method provided in this application adds a timed curve scanning process (i.e., a second curve scanning process) after the perturbation processing. Compared with the second curve scanning process, it focuses on avoiding the omission of global peaks caused by incomplete scanning. Especially for scenarios where shadow occlusion and other factors cause multiple peaks in the PU characteristic curve, it can completely cover all potential peak ranges, ensuring that subsequent perturbation processing can lock the global maximum power point rather than local peaks, thus significantly improving tracking accuracy.

[0157] This is illustrative; please refer to it. Figure 8 The flowchart of a control method based on an inverter provided in this application includes the following steps 801 to 806.

[0158] Step 801: Upon receiving a curve scan instruction, perform a first curve scan process on the photovoltaic module.

[0159] The power point indicates the output power of the photovoltaic module at the corresponding operating voltage; the first curve scanning process is used to control the operating voltage of the photovoltaic module to be gradually increased based on the first scanning step size.

[0160] In some embodiments, when the inverter system (or controller) is in standby mode, if a curve scan command is received, a first curve scan process is performed on the photovoltaic module.

[0161] Step 802: If the photovoltaic module meets the first curve scanning conditions, stop the first curve scanning process and determine the first voltage range based on the power point obtained from the first curve scanning process.

[0162] The power change trend corresponding to the power point within the first voltage range is first increasing and then decreasing.

[0163] Step 803: When the current time reaches the time of the delay disturbance, perform disturbance processing on the operating voltage of the photovoltaic module within the first voltage range to obtain the first power point; control the operation of the photovoltaic module based on the first operating voltage corresponding to the first power point.

[0164] Step 804: While the photovoltaic module is in the first scan cycle at the current moment, perform the second curve scan process.

[0165] The second curve scanning process is used to control the gradual increase of the operating voltage of the photovoltaic module based on the second scanning step size.

[0166] The first scanning cycle has a preset cycle duration. In other words, in this application, after the perturbation process is performed, the photovoltaic module will be subjected to a second curve scanning process at each preset cycle duration to re-track the maximum power point.

[0167] Step 805: If the photovoltaic module meets the second curve scanning conditions, stop the second curve scanning process and determine the second voltage range based on the power point obtained from the second curve scanning process.

[0168] Among them, the power change trend corresponding to the power point in the second voltage range is first increasing and then decreasing.

[0169] Step 806: When the current time reaches the time of the delay disturbance, perform disturbance processing on the operating voltage of the photovoltaic module within the second voltage range to obtain the second power point; control the operation of the photovoltaic module based on the second operating voltage corresponding to the second power point.

[0170] The second power point meets the maximum power point requirement for photovoltaic modules.

[0171] The inverter-based control method provided in this application can be applied to the maximum power point tracking (MPPT) processing task of photovoltaic modules. The following section combines... Figures 9-18 Let me introduce it.

[0172] (I) Maximum Power Point Tracking (MPPT) Processing Task Flow.

[0173] Figure 9 This diagram illustrates the state transitions for the Maximum Power Point Tracking (MPPT) processing task provided in this application. Figure 9 As shown, when the controller is in standby state 910, if a curve scan command is received, the controller enters curve scan state 920. In curve scan state 920, the controller performs the first curve scan process described above. Optionally, when the controller is in standby state 910, if the operating voltage of the photovoltaic module is detected to have returned to normal, a curve scan command is triggered; or, the controller is in standby state 910 for a preset standby time, a curve scan command is triggered; or, the controller receives a curve scan command sent from the cloud, etc., which are not limited here.

[0174] If the photovoltaic module meets the conditions for completing the first scan, the first curve scan processing is stopped, and the controller enters a pause state 930. If the controller remains in the pause state 930 for a duration equal to the delay period (i.e., the "current moment reaches the delay disturbance moment" mentioned above), the controller enters a maximum power point tracking (MPPT) state 940. In MPPT state 940, the controller performs the aforementioned disturbance processing to determine the first power point that meets the maximum power point requirements. Then, the controller performs this process at preset intervals (i.e., ... Figure 9 When the periodic scan time is up, the system enters periodic scan state 950. In periodic scan state 950, the controller performs the second curve scan process described above.

[0175] When the photovoltaic module meets the conditions for completing the second scan, the second curve scan process is stopped, and the controller enters a pause state 930. After the controller remains in the pause state 930 for the required delay time, it enters the maximum power point tracking (MPPT) state 940. In the final MPPT state 940, the controller performs the aforementioned perturbation process to determine a second power point that meets the MPPT requirements. Each cycle, the controller cyclically switches between "MPPT state 940 - cycle scan state 950 - pause state 930".

[0176] In the maximum power point tracking state 940, if the controller stops due to a fault or is in a power-off state, the controller enters the standby state 910. At this time, the controller will re-enter the curve scanning state 920 according to the received curve scanning command. Then, in the curve scanning state 920, the controller performs the first curve scanning process mentioned above. The subsequent process is described above and will not be repeated here.

[0177] Figure 10 A flowchart of the maximum power point tracking (MPPT) processing task provided in this application is shown, which includes the following steps:

[0178] Step 1: Begin.

[0179] Begin the maximum power point tracking (MPPT) processing task provided in this application.

[0180] Step 2: Calculate power periodically.

[0181] The real-time PV power of the photovoltaic module is calculated at fixed intervals (e.g., every 200 milliseconds). For illustration, PV voltage and PV current are collected at fixed intervals, and the PV power is calculated using the formula: "PV power = PV voltage × PV current". Here, PV voltage and PV current are the operating voltage and current of the photovoltaic module, and PV power is the output power of the photovoltaic module.

[0182] Step 3: Run the MPPT algorithm.

[0183] The MPPT algorithm is the inverter-based control method provided in this application. Running the MPPT algorithm means that the MPPT controller runs the MPPT algorithm.

[0184] Step 4: Record the PV power, PV voltage, and PV current of the previous and current measurements.

[0185] During the MPPT algorithm operation, the PV power, PV voltage, and PV current collected in step 2 are recorded for comparison and judgment of power change trends.

[0186] Step 5: Record the current bus voltage.

[0187] During the MPPT algorithm operation, the current bus voltage is recorded to prevent overvoltage or undervoltage.

[0188] Step 6: Record the maximum power value.

[0189] During the MPPT algorithm operation, the maximum power value currently collected is recorded. The method for recording the maximum power value is as follows: compare the previous PV power collected in step 4 with the current PV power. If the previous PV power is greater than the current PV power, update the maximum power value to the previous PV power; if the previous PV power is less than or equal to the current PV power, update the maximum power value to the current PV power.

[0190] Step 7: Process MPPT commands.

[0191] MPPT refers to the MPPT controller, also known as the controller mentioned above. MPPT instructions include, but are not limited to, at least one of the following: power-off instructions, curve scan instructions, and parallel instructions.

[0192] Step 8: Determine if a shutdown command has been received.

[0193] That is, to determine whether the MPPT controller has received a shutdown command.

[0194] Step 9: If yes, command Boost to shut down, MPPT will enter standby mode, and MPPT will be in standby state.

[0195] If the MPPT controller receives a shutdown command, it commands the Boost circuit to shut down, and the MPPT controller enters standby mode. In the inverter, Boost refers to the Boost circuit, which is the core component for achieving Maximum Power Point Tracking (MPPT). By adjusting the duty cycle of the Boost circuit, the MPPT controller can change the impedance of the photovoltaic module, thereby controlling the module's operating voltage and current.

[0196] Step 10: MPPT power limiting processing.

[0197] Optionally, if the MPPT controller enters step 10 after receiving a shutdown command, the MPPT power limiting process means that the MPPT controller gradually reduces the operating voltage of the photovoltaic module by adjusting the duty cycle of the Boost circuit, so that the PV power of the photovoltaic module gradually decreases from the current value to a safe threshold (such as close to zero), rather than directly cutting off the power output, so as to avoid drastic fluctuations in the bus voltage (overvoltage or undervoltage) due to sudden power changes.

[0198] Step 11: If not, determine whether a curve scan command has been received.

[0199] If the MPPT controller does not receive a shutdown command, determine whether the MPPT has received a curve scan command.

[0200] Step 12: If yes, determine whether it is in factory DC mode.

[0201] If the MPPT controller receives a curve scan command, it determines whether the inverter is in factory DC mode. Factory DC mode refers to a specific DC operating mode adopted by the inverter during factory testing or commissioning.

[0202] Step 13: If yes, command Boost to enter constant current mode, MPPT to enter constant current scanning mode, and MPPT to enter curve scanning mode.

[0203] If the inverter is in factory DC mode, the Boost controller is commanded to enter constant current mode, and the MPPT controller enters constant current scanning mode. The MPPT controller is in curve scanning mode. The specific steps include the following:

[0204] (1) Set a current setting value (usually starting from 0).

[0205] (2) The Boost circuit will adjust its duty cycle to stabilize the operating current of the photovoltaic module at this current setting value.

[0206] (3) In order to maintain constant current output, the operating voltage of the photovoltaic module will automatically stabilize at a corresponding value.

[0207] (4) Record the PV voltage, PV current and PV power at this time, and you will get a point on the PU characteristic curve.

[0208] (5) Then, increase the current setting value by one step and repeat steps (2)-(4) until the entire preset current range is scanned to obtain a more complete PU characteristic curve of the photovoltaic module, thereby finding the maximum power point.

[0209] Optionally, if step 10 is entered in the factory DC mode, the MPPT power limiting process means that the MPPT controller adjusts the duty cycle of the Boost circuit to stabilize the operating current of the photovoltaic module at the current set value, thereby achieving power limiting.

[0210] Step 14: If not, command Boost to enter constant voltage mode, MPPT to enter scanning mode, and MPPT to enter curve scanning mode.

[0211] If the inverter is not in factory DC mode, the Boost controller is commanded to enter constant voltage mode, and the MPPT controller enters scan mode. The MPPT controller is in curve scan mode. The specific steps include the following:

[0212] (1) Obtain the voltage setting value (i.e., the working voltage determined based on the first scan step size above).

[0213] (2) The Boost circuit will adjust its duty cycle to stabilize the operating voltage of the photovoltaic module at this voltage setting value.

[0214] (3) In order to maintain constant voltage output, the operating current of the photovoltaic module will automatically stabilize at a corresponding value.

[0215] (4) Record the PV voltage, PV current and PV power at this time, so that a point on the power-voltage curve is obtained.

[0216] (5) Then, obtain the next voltage setting value and repeat steps (2)-(4) until the first scan completion condition is met.

[0217] Optionally, if step 10 is entered in non-factory DC mode, then MPPT power limiting means that the MPPT controller adjusts the duty cycle of the Boost circuit to stabilize the operating voltage of the photovoltaic module at the voltage set value, thereby achieving power limiting.

[0218] Step 15: If not, determine whether a parallel connection command has been received.

[0219] If the MPPT controller does not receive a curve scan command, determine whether the MPPT controller has received a parallel command.

[0220] Step 16: If yes, the command Boost parallel will be executed, and MPPT will enter a waiting command state.

[0221] If the MPPT controller receives a parallel connection command, it instructs the Boost circuit to connect in parallel, and the MPPT controller enters a waiting command state. Boost parallel connection means that the current MPPT controller will operate in parallel with other MPPT controllers, ceasing to control the Boost circuit based on the results calculated by the current MPPT controller, and instead preparing to receive an external command to control the duty cycle of the Boost circuit, ensuring the photovoltaic modules operate at a specified voltage or power. The MPPT controller entering a waiting command state means that the current MPPT controller itself switches to a waiting command state, pausing the current active control logic (such as maximum power point tracking, curve scanning, etc.) until it receives a new control command (such as a shutdown command, curve scanning command, etc.), after which it will execute subsequent operations. Optionally, if step 10 is entered when the MPPT controller enters a waiting command state, then the MPPT power limiting process means that the MPPT controller limits the power according to the external command.

[0222] Optionally, if the MPPT controller does not wait for a command to proceed to step 10, the MPPT power limiting process refers to the MPPT controller making its own decision based on its internal MPPT algorithm and actively limiting the output power of the photovoltaic module by adjusting the duty cycle of the Boost circuit.

[0223] Step 17: End.

[0224] (II) The first curve scan processing flow in the maximum power point tracking (MPPT) processing task.

[0225] Figure 11 A flowchart of the first curve scanning process provided in this application is shown, which includes the following steps:

[0226] Step 1: Begin.

[0227] Optionally, the first curve scan process begins when the MPPT controller receives a curve scan command.

[0228] Step 2: Determine whether the conditions for stopping the scan are met.

[0229] The condition for stopping scanning is the same as the first scan completion condition mentioned above, which means determining whether the photovoltaic module meets the first scan completion condition.

[0230] Step 3: If not, set the PV reference value of Boost to equal the scan step size of MPPT.

[0231] If the photovoltaic module does not meet the conditions for completing the first scan, the PV reference value of the Boost is set to be equal to the scan step size of the MPPT. The PV reference value being equal to the scan step size of the MPPT means: previous PV reference value = current PV reference value - MPPT scan step size.

[0232] The PV reference value is the operating voltage of the photovoltaic module mentioned above. "Previous PV reference value = Current PV reference value - MPPT scan step size" means that the MPPT controller adds the reference voltage value corresponding to the MPPT scan step size to the previous PV reference value each time, thus obtaining the current PV reference value. This means that during each scan, the MPPT controller adds a scan step size to the previous voltage, gradually increasing the operating voltage to collect power points (power = voltage × current) at different voltages. The purpose is to gradually cover the operating voltage range of the photovoltaic module by continuously increasing the voltage, recording the power corresponding to each voltage, and accumulating data for subsequently determining the first voltage range where the maximum power point is located.

[0233] Step 4: Double the scan step size of MPPT.

[0234] That is, the scan step size of MPPT will double after each adjustment. For example, if the initial step size is ΔV1 = V, then the next step size is ΔV2 = 2V, the next one is ΔV3 = 4V, and so on. Here, V can be regarded as the "reference voltage corresponding to the first scan step size" mentioned above.

[0235] Step 5: The maximum scan step size limit for MPPT is Dmax.

[0236] Optionally, Dmax is set to 10, which is the maximum boost voltage mentioned above.

[0237] To illustrate, taking Dmax=10 as an example, Table 1 shows a schematic process of the first curve scanning process:

[0238] Table 1

[0239]

[0240] Step 6: If yes, MPPT enters a paused state.

[0241] If the photovoltaic module meets the conditions for the first scan to be completed, the MPPT controller enters a temporary state.

[0242] The process after entering the temporary state is as follows: Figure 12 As shown, Figure 12 A flowchart illustrating the temporary holding state provided in this application is shown, which includes the following steps:

[0243] Step 1: Begin.

[0244] If the photovoltaic module meets the first scan completion condition, the MPPT controller enters a pause state. Alternatively, if the photovoltaic module meets the second scan completion condition, the MPPT controller enters a pause state.

[0245] Step 2: Determine if the delay time has expired.

[0246] That is, it determines whether the duration for which the MPPT controller remains in the temporary state has reached the delay duration.

[0247] Step 3: If yes, enter maximum power point tracking mode.

[0248] If the MPPT controller remains in the paused state for the duration of the delay, the MPPT controller enters the maximum power point tracking state and ends the paused state.

[0249] Step 4: If not, end.

[0250] If the MPPT controller remains in the paused state for less than the required delay time, the process ends and periodically returns to step 2, "determine if the delay time has expired," until the MPPT controller remains in the paused state for the required delay time. In this case, the MPPT controller enters the maximum power point tracking state and ends the paused state.

[0251] (III) Disturbance handling process in the maximum power point tracking (MPPT) task.

[0252] Figure 13 A flowchart of the disturbance processing provided in this application is shown, which includes the following steps:

[0253] Step 1: Begin.

[0254] Step 2: Determine if MPPT is paused.

[0255] That is, determine whether the duration of the MPPT controller remaining in the pause state has reached the delay time: if it has, proceed to step 3 below. If it has not reached the delay time, end the process and periodically return to step 2 of (II) above, "determine whether the delay time has expired", until the duration of the MPPT controller remaining in the pause state reaches the delay time, then proceed to step 3 below.

[0256] Step 3: Determine if MPPT scanning is enabled.

[0257] That is, determine whether the MPPT controller is in the active state of the first curve scan processing. If the MPPT controller is in the active state of the first curve scan processing, the process ends, indicating that the MPPT controller is currently in the first curve scan processing flow. If the MPPT controller is not in the active state of the first curve scan processing, proceed to step 4.

[0258] Step 4: Determine if a periodic scan is in progress. If yes, end the process; otherwise, proceed to Step 5.

[0259] That is, determine whether the MPPT controller is in the second curve scan processing flow. If the MPPT controller is in the second curve scan processing flow, the process ends. If the MPPT controller is not in the second curve scan processing flow, proceed to step 5.

[0260] Step 5: Record the current PV voltage and the previous PV voltage.

[0261] The current PV voltage, which is the current operating voltage of the photovoltaic module, is represented by vpv_now; the previous PV voltage, which is the operating voltage of the photovoltaic module at the time of the last disturbance, is represented by vpv_last.

[0262] Step 6: Determine whether the power of the two PV channels has reached the power limit state.

[0263] If the power of both PV channels reaches the power limit state, proceed to step 7; if the power of both PV channels does not reach the power limit state, proceed to step 9.

[0264] To illustrate, the inverter is currently connected to two independent photovoltaic inputs (PV1, PV2). The MPPT controller needs to know the real-time power of both inputs, ppv1 and ppv2, and determine whether the power of the two inputs has reached the power limit state, that is, whether ppv1 + ppv2 is greater than or equal to Plimit (the maximum allowable output power of the whole machine).

[0265] Step 7: Set the PV voltage to the voltage that the current PV is tracking.

[0266] If ppv1+ppv2 is greater than or equal to Plimit, the Boost circuit adjusts the operating voltage of the photovoltaic module to the currently tracked PV voltage, i.e., vpv_now_trace, and then proceeds to step 8.

[0267] Step 8: Set MPPT_state to 0 and vpv_step = MIN_STEP.

[0268] After setting the PV voltage to the voltage that the current PV is tracking, set MPPT_state to 0, vpv_step = MIN_STEP, and then end.

[0269] Among them, setting MPPT_state to 0 and vpv_step = MIN_STEP (minimum perturbation step size) is used to prepare for restarting perturbation processing in the future.

[0270] Step 9: Determine whether the bus voltage has reached the maximum bus voltage when Boost is operating.

[0271] If the bus voltage reaches (is greater than or equal to) the maximum bus voltage when the Boost is operating, proceed to step 10; if the bus voltage does not reach (is less than) the maximum bus voltage when the Boost is operating, proceed to step 11.

[0272] Step 10: Set MPPT_state = 0 and vpv_step = MIN_STEP.

[0273] After determining that the bus voltage has reached (greater than or equal to) the maximum bus voltage when Boost is operating, set MPPT_state = 0, vpv_step = MIN_STEP, and then end.

[0274] Optionally, MIN_STEP can be set to 2.

[0275] Step 11: Determine if MPPT_state is equal to 0.

[0276] If MPPT_state equals 0, proceed to step 12; if MPPT_state does not equal 0, proceed to step 13.

[0277] Step 12: vpv_next=vpv_now_trace+step, MPPT_state=1.

[0278] When MPPT_state = 0, calculate the next target voltage (vpv_next) = current tracking voltage (vpv_now_trace) + perturbation step size (step), and set MPPT_state to 1. Then proceed to step 22.

[0279] It should be noted that vpv_now refers to the current real-time operating voltage of the photovoltaic module, while vpv_now_trace refers to the target voltage that the MPPT controller is currently tracking. It is the voltage value that the MPPT controller expects the photovoltaic module to operate at (i.e., the voltage setpoint to be adjusted to in the next step) calculated by the MPPT controller based on the disturbance handling logic.

[0280] Step 13: Determine if MPPT_state is equal to 1.

[0281] If MPPT_state is not equal to 0, then check if MPPT_state is equal to 1. If MPPT_state is equal to 1, proceed to step 14; if MPPT_state is not equal to 1, proceed to step 15.

[0282] Step 14: vpv_next=vpv_last_trace, MPPT_state=2.

[0283] When MPPT_state = 1, calculate the next target voltage (vpv_next) equal to the previous tracking voltage (vpv_now_trace), and set MPPT_state to 2. Then proceed to step 22.

[0284] It should be noted that vpv_last refers to the actual operating voltage of the photovoltaic module in the last operation, while vpv_last_trace refers to the target voltage that the MPPT controller tracked in the last operation. This is the voltage value that the MPPT controller expects the photovoltaic module to operate at, calculated by the disturbance handling logic (i.e., the voltage that the photovoltaic module was planned to reach in the previous step).

[0285] Step 15: Determine if MPPT_state is equal to 2.

[0286] If MPPT_state is not equal to 1, continue to check if MPPT_state is equal to 2. If MPPT_state is equal to 2, proceed to step 16; if MPPT_state is not equal to 2, proceed to step 21.

[0287] Step 16: Calculate the power change dppv.

[0288] When MPPT_state = 2, calculate the power change dppv. Optionally, dppv = (current power ppv_now - previous power ppv_last) - (previous power ppv_last - power two years ago ppv_last2).

[0289] Step 17: Variable step size correction.

[0290] Variable step size correction means dynamically adjusting the disturbance step size vpv_step according to the power change dppv. vpv_step = disturbance coefficient k × [dppv ÷ (current voltage vpv_now - previous voltage vpv_last)].

[0291] Step 18: Determine if dppv is greater than 0.

[0292] Based on the calculation result dppv from step 16, determine whether it is greater than 0.

[0293] Step 19: If dppv is greater than 0, move to the next point.

[0294] If dppv is greater than 0, it is determined that the previous disturbance direction (the positive disturbance in step 12) was correct, and the power is trending towards increasing. Therefore, the MPPT controller decides to maintain the same disturbance direction (continue to increase the voltage). Then, it proceeds to step 22.

[0295] Step 20: If dppv is not greater than 0, return to the previous point, MPPT_state = 0.

[0296] If dppv is not greater than (≤) 0, the direction of the previous disturbance (the positive disturbance in step 12) is determined to be incorrect. Therefore, the MPPT controller decides to reverse the disturbance (reduce the voltage) and resets MPPT_state to 0 to prepare for the next disturbance cycle. Then proceed to step 22.

[0297] Step 21: vpv_step = MAX_STEP, MPPT_state = 0.

[0298] If MPPT_state is not equal to 2, set vpv_step = MAX_STEP (maximum perturbation step size) and MPPT_state = 0. Then proceed to step 22.

[0299] Optionally, MAX_STEP can be set to 10.

[0300] Step 22: PV current and PV voltage limits.

[0301] Voltage limits include the minimum and maximum operating voltages of the photovoltaic module; current limits include the maximum and minimum operating currents of the photovoltaic module. If vpv_next exceeds the voltage limit, it is corrected to the nearest safe voltage value (e.g., if it is higher than the maximum voltage, it is set to the maximum voltage; if it is lower than the minimum voltage, it is set to the minimum voltage). If the expected current corresponding to vpv_next exceeds the current limit, the voltage target value is also adjusted (e.g., lowering the voltage to reduce the current, or raising the voltage to increase the current) to ensure that the current is within the safe range.

[0302] Step 23: End.

[0303] The following is combined with Figures 14-16 Here is an example of a specific perturbation processing method in this application:

[0304] like Figure 14 As shown, assuming that when the first curve scanning process (or the second curve scanning process) stops, the operating point of the photovoltaic module is power point a, and the first voltage range determined by the first curve scanning process is the voltage range between power point e and power point a (or the second voltage range determined by the second curve scanning process is the voltage range between power point e and power point a), then starting from power point a, a perturbation process is performed within the voltage range between power point e and power point a, which includes at least the following perturbation process:

[0305] Disturbance process 1:

[0306] Calculate the power ppv_now, vpv_now, and ipv_now at the current point (power, voltage, and current at point a), which is the PV power, PV voltage, and PV current corresponding to the current power point a.

[0307] vpv_now_trace=vpv_now; vpv_last_trace=vpv_last; vpv_last=0; vpv_last_trace=0;

[0308] MPPT_state = 0, so vpv_next = vpv_now_trace + step, where step defaults to -10 (tracing from right to left); then, set MPPT_state to 1;

[0309] Output the set value of the next VPV voltage: Output_set_vpv = vpv_next; theoretically, it will reach point B after control.

[0310] Record the power and voltage from the last test:

[0311] ppv_last2 = ppv_last = 0 (default is 0).

[0312] ppv_last = ppv_now(power at point a),

[0313] vpv_last2 = vpv_last = 0, the default value is 0.

[0314] vpv_last = vpv_now (voltage at point a),

[0315] ipv_last2 = ipv_last,

[0316] ipv_last = ipv_now (current at point a).

[0317] Disturbance process 2:

[0318] Calculate the power ppv_now, vpv_now, and ipv_now at the current point (power, voltage, and current at point b), which are the PV power, PV voltage, and PV current corresponding to the current power point b.

[0319] vpv_now_trace = vpv_now(voltage at point b); vpv_last_trace = vpv_last(voltage at point a);

[0320] MPPT_state = 1, so vpv_next = vpv_last_trace (return to point a); MPPT_state is set to 2;

[0321] Output the set value of the next VPV voltage: Output_set_vpv = vpv_next; theoretically, after control, it will return to point A;

[0322] Record the power and voltage from the last test:

[0323] ppv_last2 = ppv_last = power at point a.

[0324] ppv_last = ppv_now (power at point b),

[0325] vpv_last2 = vpv_last = voltage at point a.

[0326] vpv_last = vpv_now (voltage at point b),

[0327] ipv_last2 = ipv_last,

[0328] ipv_last = ipv_now.

[0329] Disturbance process 3:

[0330] Calculate the power ppv_now, vpv_now, and ipv_now at the current point (power, voltage, and current at point a), which is the PV power, PV voltage, and PV current corresponding to the current power point a.

[0331] vpv_now_trace = vpv_now(voltage at point b); vpv_last_trace = vpv_last(voltage at point a);

[0332] MPPT_state = 2; MPPT_state = 0, which means switching MPPT_state from 2 to 0;

[0333] Calculate the power at point a - power at point b - (power at point b - power at point a) = dppv = 2pa - 2pb < 0; step = 0.16 × dppv / (vpv_now_trace - vpv_last_trace); the calculated step here is < 0;

[0334] If dppv > 0, the power at point a is high, so continue tracing: vpv_next = vpv_now_trace + step (voltage at point a plus a step size); Trace_step (perturbation step size) = 1; if dppv < 0, the power at the previous point b is high, so return to the previous point b; vpv_next = vpv_last_trace (voltage at point b); MPPT_state = 0;

[0335] Output the set value of the next VPV voltage: Output_set_vpv = vpv_next; theoretically, after control, it returns to point B;

[0336] Record the power and voltage from the last test:

[0337] ppv_last2 = ppv_last = power at point b.

[0338] ppv_last = ppv_now(power at point a),

[0339] vpv_last2 = vpv_last = voltage at point b.

[0340] vpv_last = vpv_now (voltage at point a),

[0341] ipv_last2 = ipv_last,

[0342] ipv_last = ipv_now.

[0343] Disturbance process 4:

[0344] Calculate the power ppv_now, vpv_now, and ipv_now at the current point (power, voltage, and current at point b);

[0345] vpv_now_trace = vpv_now(voltage at point b); vpv_last_trace = vpv_last(voltage at point a);

[0346] MPPT_state = 0, so vpv_next = vpv_last_trace + step (the previous calculation result step < 0); MPPT_state = 1;

[0347] Output the set value of the next VPV voltage: Output_set_vpv = vpv_next; theoretically, it will reach point C after control.

[0348] Record the power and voltage from the last test:

[0349] ppv_last2 = ppv_last = power at point a.

[0350] ppv_last = ppv_now (power at point b),

[0351] vpv_last2 = vpv_last = voltage at point a.

[0352] vpv_last = vpv_now (voltage at point b),

[0353] ipv_last2 = ipv_last,

[0354] ipv_last = ipv_now.

[0355] Disturbance process 5:

[0356] Calculate the power ppv_now, vpv_now, and ipv_now at the current point (power, voltage, and current at point c), which are the PV power, PV voltage, and PV current corresponding to the current power point c.

[0357] vpv_now_trace = vpv_now(voltage at point C); vpv_last_trace = vpv_last(voltage at point B);

[0358] MPPT_state = 1, so vpv_next = vpv_last_trace (returning to the previous point b); MPPT_state is set to 2;

[0359] Output the set value of the next VPV voltage: Output_set_vpv = vpv_next; theoretically, after control, it returns to point B;

[0360] Record the power and voltage from the last test:

[0361] ppv_last2 = ppv_last = power at point b.

[0362] ppv_last = ppv_now (power at point c),

[0363] vpv_last2 = vpv_last = voltage at point b.

[0364] vpv_last = vpv_now (voltage at point C),

[0365] ipv_last2 = ipv_last,

[0366] ipv_last = ipv_now.

[0367] Disturbance process 6:

[0368] Calculate the power ppv_now, vpv_now, and ipv_now at the current point (power, voltage, and current at point b);

[0369] vpv_now_trace = vpv_now(voltage at point b); vpv_last_trace = vpv_last(voltage at point c);

[0370] MPPT_state = 2, MPPT_state = 0, which means switching MPPT_state from 2 to 0;

[0371] Calculate the power at point b - power at point c - (power at point c - power at point b) = dppv = 2pb - 2pc < 0; step = 0.16 × dppv / (vpv_now_trace - vpv_last_trace); the calculated step here is < 0.

[0372] If dppv > 0, the power at point b is high, so continue tracing: vpv_next = vpv_now_trace + step (voltage at point b plus a step size); MPPT_state = 1. If dppv < 0, the power at the previous point c is high, so return to the previous point c; vpv_next = vpv_last_trace (voltage at point c); MPPT_state = 0.

[0373] Output the next set value of the VPV voltage: Output_set_vpv = vpv_next. Theoretically, after control, it returns to point C.

[0374] Record the power and voltage from the last test:

[0375] ppv_last2 = ppv_last = power at point c.

[0376] ppv_last = ppv_now (power at point b),

[0377] vpv_last2 = vpv_last = voltage at point C.

[0378] vpv_last = vpv_now (voltage at point b),

[0379] ipv_last2 = ipv_last,

[0380] ipv_last = ipv_now.

[0381] Disturbance process 7:

[0382] Calculate the power ppv_now, vpv_now, and ipv_now at the current point (power, voltage, and current at point c);

[0383] vpv_now_trace = vpv_now(voltage at point C); vpv_last_trace = vpv_last(voltage at point B);

[0384] MPPT_state=0, so vpv_next=vpv_now_trace+step(<0)MPPT_state=1;

[0385] Output the set value of the next VPV voltage: Output_set_vpv = vpv_next; theoretically, it will reach point d after control.

[0386] Record the power and voltage from the last test:

[0387] ppv_last2 = ppv_last = power at point b.

[0388] ppv_last = ppv_now (power at point c),

[0389] vpv_last2 = vpv_last = voltage at point b.

[0390] vpv_last = vpv_now (voltage at point C),

[0391] ipv_last2 = ipv_last,

[0392] ipv_last = ipv_now.

[0393] Disturbance process 8:

[0394] Calculate the power ppv_now, vpv_now, and ipv_now at the current point (power, voltage, and current at point d), which are the PV power, PV voltage, and PV current corresponding to the current power point d.

[0395] vpv_now_trace = vpv_now(voltage at point d); vpv_last_trace = vpv_last(voltage at point c);

[0396] MPPT_state = 1, so vpv_next = vpv_last_trace (returning to the previous point c); MPPT_state = 2;

[0397] Output the next set value of the VPV voltage: Output_set_vpv = vpv_next. Theoretically, after control, it returns to point C.

[0398] Record the power and voltage from the last test:

[0399] ppv_last2 = ppv_last = power at point c.

[0400] ppv_last = ppv_now (power at point d),

[0401] vpv_last2 = vpv_last = voltage at point C.

[0402] vpv_last = vpv_now (voltage at point d),

[0403] ipv_last2 = ipv_last,

[0404] ipv_last = ipv_now.

[0405] Disturbance process 9:

[0406] Calculate the power ppv_now, vpv_now, and ipv_now at the current point (power, voltage, and current at point c), which are the PV power, PV voltage, and PV current corresponding to the current power point c.

[0407] vpv_now_trace = vpv_now(voltage at point C); vpv_last_trace = vpv_last(voltage at point D);

[0408] MPPT_state=2, MPPT_state=0;

[0409] Calculate the power at point c - power at point d - (power at point d - power at point c) = dppv = 2pc - 2pd < 0; step = 0.16 × dppv / (vpv_now_trace - vpv_last_trace), where step calculated here is < 0;

[0410] If dppv > 0, the power at the current point c is high, so continue tracing; vpv_next = vpv_now_trace + step (voltage at point b plus a step size); MPPT_state = 1; If dppv < 0, the power at the previous point d is high, so return to the previous point d; vpv_next = vpv_last_trace (voltage at point d); MPPT_state = 0;

[0411] Output the next set value of the VPV voltage: Output_set_vpv = vpv_next. Theoretically, after control, it returns to point d.

[0412] Record the power and voltage from the last test:

[0413] ppv_last2 = ppv_last = power at point c.

[0414] ppv_last = ppv_now (power at point d),

[0415] vpv_last2 = vpv_last = voltage at point C.

[0416] vpv_last = vpv_now (voltage at point d),

[0417] ipv_last2 = ipv_last,

[0418] ipv_last = ipv_now.

[0419] Disturbance process 10:

[0420] Calculate the power ppv_now, vpv_now, and ipv_now at the current point (power, voltage, and current at point d), which are the PV power, PV voltage, and PV current corresponding to the current power point d.

[0421] vpv_now_trace = vpv_now(voltage at point d); vpv_last_trace = vpv_last(voltage at point c);

[0422] MPPT_state=0, so vpv_next=vpv_now_trace+step(<0); MPPT_state=1;

[0423] Output the set value of the next VPV voltage: Output_set_vpv = vpv_next. Theoretically, this will reach point E after control.

[0424] Record the power and voltage from the last test:

[0425] ppv_last2 = ppv_last = power at point c.

[0426] ppv_last = ppv_now (power at point d),

[0427] vpv_last2 = vpv_last = voltage at point C.

[0428] vpv_last = vpv_now (voltage at point d),

[0429] ipv_last2 = ipv_last,

[0430] ipv_last = ipv_now.

[0431] Disturbance process 11:

[0432] Calculate the power ppv_now, vpv_now, and ipv_now at the current point (power, voltage, and current at point e), which are the PV power, PV voltage, and PV current corresponding to the current power point e.

[0433] vpv_now_trace = vpv_now (voltage at point e); vpv_last_trace = vpv_last (voltage at point d);

[0434] MPPT_state=1, so vpv_next=vpv_last_trace, MPPT_state=2;

[0435] Output the next set value of the VPV voltage: Output_set_vpv = vpv_next. Theoretically, after control, it returns to point d.

[0436] Record the power and voltage from the last test:

[0437] ppv_last2 = ppv_last = power at point d.

[0438] ppv_last = ppv_now (power at point e),

[0439] vpv_last2 = vpv_last = voltage at point d.

[0440] vpv_last = vpv_now (voltage at point e),

[0441] ipv_last2 = ipv_last,

[0442] ipv_last = ipv_now.

[0443] Disturbance process 12:

[0444] Calculate the power ppv_now, vpv_now, and ipv_now at the current point (power, voltage, and current at point d), which are the PV power, PV voltage, and PV current corresponding to the current power point d.

[0445] vpv_now_trace = vpv_now(voltage at point d); vpv_last_trace = vpv_last(voltage at point e);

[0446] MPPT_state=2, MPPT_state=0;

[0447] Calculate the power at point d - power at point e - (power at point e - power at point d) = dppv = 2pd - 2pe > 0; step = 0.16 × dppv / (vpv_now_trace - vpv_last_trace), where step calculated here is > 0;

[0448] If dppv > 0, the power at the current point d is high, so continue tracing: vpv_next = vpv_now_trace + step (voltage at point d plus a step size), MPPT_state = 1; if dppv < 0, the power at the previous point e is high, so return to the previous point e; vpv_next = vpv_last_trace (voltage at point e); MPPT_state = 0.

[0449] Continue perturbation until the maximum power point requirement is reached, then stop perturbation processing. As mentioned above, the maximum power point requirement includes:

[0450] After N consecutive perturbation operations, the absolute value of the power difference between the current output power and the previous output power of the photovoltaic module is less than a very small first power threshold; and the absolute value of the voltage difference between the current operating voltage and the previous operating voltage of the photovoltaic module is less than a very small first voltage threshold.

[0451] (iv) The second curve scan process in the maximum power point tracking (MPPT) processing task.

[0452] Figure 17 The flowchart of the second curve scanning process provided in this application includes the following steps:

[0453] Step 1: Begin.

[0454] Step 2: Determine if MPPT scanning is enabled.

[0455] That is, determine whether the MPPT controller is in the active state of the first curve scan processing. If the MPPT controller is in the active state of the first curve scan processing, the process ends, indicating that the MPPT controller is currently in the first curve scan processing flow. If the MPPT controller is not in the active state of the first curve scan processing, proceed to step 3.

[0456] Step 3: If not, determine whether MPPT is in cyclic scanning standby mode.

[0457] If the MPPT controller is not in the active state of the first curve scan processing, determine whether the MPPT controller is in the cyclic scan standby state. If yes, proceed to step 6; otherwise, proceed to step 4.

[0458] Step 4: If not, determine whether MPPT is in a cyclic scan startup state.

[0459] If the MPPT controller is not in a cyclic scanning standby state, determine whether the MPPT controller is in a cyclic scanning start state. If yes, proceed to step 8; otherwise, proceed to step 5.

[0460] Step 5: If not, determine whether MPPT is in a cyclic scan state.

[0461] If it is determined that the MPPT controller is not in a cyclic scan start state, then determine whether the MPPT controller is in a cyclic scan in progress state. If yes, proceed to step 11; otherwise, proceed to step 14.

[0462] Step 6: If yes, determine if the scan cycle time has elapsed.

[0463] When the MPPT controller is determined to be in cyclic scanning standby mode, it checks whether the scan cycle time has elapsed, i.e., whether the current moment is within the first scan cycle. If yes, proceed to step 7; otherwise, end the current process.

[0464] Step 7: If the scan cycle time is up, set the scan status to MPPT start scan status.

[0465] That is, when it is determined that the current moment is in the first scan cycle, the scan state of the MPPT controller is set to MPPT start scan state, and then it ends.

[0466] Step 8: If MPPT is in a cyclic scan startup state, determine whether the scan startup conditions are met.

[0467] When it is determined that the MPPT controller is in a cyclic scanning standby state, it is checked whether the scanning start condition is met. If yes, proceed to step 9; otherwise, end the current process.

[0468] Step 9: If the scan start conditions are met, set the scan status to MPPT cyclic scan status.

[0469] When the scan initiation conditions are met, the MPPT controller's scan state is set to MPPT cyclic scan state. Illustratively, the scan initiation conditions include the photovoltaic module's current operating voltage being greater than or equal to the photovoltaic module's minimum operating voltage. Step 10: Set pv_set = pv_set + 10.

[0470] The second curve scan current voltage setting value pv_set is set to the previous voltage setting value pv_set + 10, which means the second scan step size is 10. It should be noted that this explanation only uses 10 as an example; the second scan step size can be set to other values ​​according to actual needs, and is not limited here.

[0471] After setting pv_set = pv_set + 10, the photovoltaic module is controlled to operate according to the current voltage setting value pv_set, and then the process ends.

[0472] In some embodiments, the second scan step size and the knight voltage corresponding to different cycles can be dynamically varied for the second scan step size. Illustratively, a neural network model (such as an LSTM or Transformer model) is pre-trained, and its inputs include: historical PV power sequences, ambient temperature, time of day, season, and the shape characteristics of the most recently scanned PU curve (such as the number of peaks and peak sharpness). The output of the neural network model is the starting voltage and the second scan step size for the next scan cycle.

[0473] Step 11: If MPPT is in cyclic scanning mode, determine whether the voltage, current or power has reached its maximum value.

[0474] When the MPPT controller is in a cyclic scanning state, it determines whether the voltage, current, or power of the current photovoltaic module has reached its maximum value.

[0475] In some embodiments, the maximum voltage of the photovoltaic module can be set to (maximum operating voltage + first preset voltage); the maximum current of the photovoltaic module can be set to (the product of the maximum operating current and the first current coefficient); the maximum power of the photovoltaic module can be set to (the product of the maximum output power and the power coefficient). For details, please refer to the description of the second scan completion conditions above, which will not be repeated here.

[0476] Step 12: If the voltage, current or power reaches its maximum value, set the scan state to MPPT standby state.

[0477] If any of the voltage, current, or power of the photovoltaic module reaches its maximum value, the MPPT controller's scanning state is set to MPPT standby state, and then the process ends.

[0478] Step 13: If the voltage, current or power has not reached its maximum value, set pv_set = pv_set + 10.

[0479] If the voltage, current, and power of the photovoltaic module have not reached their maximum values, set pv_set = pv_set + 10, control the photovoltaic module to operate according to the current voltage setting value pv_set, and then end.

[0480] Step 14: If MPPT is not in cyclic scanning mode, set the scanning mode to MPPT standby mode.

[0481] If it is determined that the MPPT controller is not in a cyclic scanning state, the scanning state is set to MPPT standby state, and then the process ends.

[0482] Step 15: End.

[0483] (v) Boost control process in maximum power point tracking (MPPT) processing task.

[0484] Figure 18 A schematic diagram of the Boost control process for the photovoltaic module provided in this application is shown. Figure 18 The photovoltaic automatic mode switching strategy shown is as follows: Two preset photovoltaic control modes are used: curve scanning mode and MPPT mode. Upon system startup or when the scan time expires, if the PV is normal, path 1 is used for PV control, performing curve scanning. Figure 18 As shown, the curve scanning unit 1802 is responsible for the curve scanning function (corresponding to the first curve scanning process and the second curve scanning process mentioned above). It quickly determines the voltage range including the maximum power point by gradually changing the power point of the photovoltaic module. During the curve scanning process, the voltage setting value output by the curve scanning unit 1802 is limited (Scan_Limit) to ensure that the voltage / current changes of the photovoltaic module are within a safe range (preventing overvoltage / overcurrent). Then, the curve scanning unit 1802 converts the limited voltage setting value into a corresponding current setting value Iref_pv, where Iref_pv represents the required current to reduce the photovoltaic voltage V. pv Adjust to the voltage setting after limiting.

[0485] After the curve scan is completed, PV control is performed using path 2 to handle disturbances. For example... Figure 18 As shown, the MPPT unit 1801 is responsible for the disturbance function (corresponding to the disturbance processing mentioned above), wherein the photovoltaic power calculation 1806 calculates the voltage V of the photovoltaic module in real time. pv and current I pv The MPPT unit 1801 calculates the voltage V in real time. pv and current I pv Determine the voltage setpoint V pv_ref The voltage setting value V pv_ref Will be related to real-time voltage V pv By comparison, the voltage difference (V) is obtained. pv_ref -V pv The voltage difference is input to the voltage loop PI controller 1803. When the voltage difference is greater than 0, the voltage loop PI controller 1803 outputs V. pv_ref The corresponding current setpoint Iref_pv; the voltage loop PI controller 1803 outputs V when the voltage difference is less than or equal to 0. pv The corresponding current setting value is Iref_pv.

[0486] The current setpoint Iref_pv will be related to the real-time current I. pv By comparison, the current difference (Iref_pv-I) is obtained. pv The current difference is input to the current loop PI controller 1804. When the current difference is greater than 0, the current loop PI controller 1804 outputs the current setpoint Iref_pv; when the voltage difference is less than or equal to 0, the current loop PI controller 1804 outputs the real-time current I. pv The current setpoint Iref_pv or the real-time current If pv Current limiting is performed to prevent excessive current from damaging the photovoltaic module or the Boost circuit. The current after current limiting is input to the modulation unit 1805, which generates a corresponding PWM control waveform based on the input current. The PWM control waveform controls the duty cycle of the Boost circuit, thereby changing the impedance of the photovoltaic module and controlling its operating voltage and current.

[0487] In summary, the method provided in this application achieves rapid, stable, and efficient maximum power point tracking (MPPT) for photovoltaic inverters through an optimized control approach. This application divides the entire MPPT process into two parts: first, curve scanning is performed to roughly locate the maximum power point range; then, a perturbation method is used for MPPT. During the initial operation of the inverter, curve scanning quickly brings the inverter close to the vicinity of the maximum power point. Near the maximum power point, a perturbation method is employed for tracking. By adding curve scanning before perturbation, the speed of the MPPT process is improved. Furthermore, this application provides timed curve scanning to avoid erroneous tracking of local maximum power points when the PU characteristic curve of the photovoltaic module has multiple peaks.

[0488] This is illustrative; please refer to it. Figure 19 It shows a structural block diagram of an inverter-based control device, which includes:

[0489] The first control module 1910 is used to perform a first curve scanning process on the photovoltaic module to obtain power points corresponding to at least three operating voltages of the photovoltaic module, wherein the power points indicate the output power of the photovoltaic module at the corresponding operating voltage; the first curve scanning process is used to control the operating voltage of the photovoltaic module to gradually increase based on a first scanning step size.

[0490] The first control module 1910 is used to determine a first voltage range based on at least three power points, wherein the power change trend corresponding to the power points within the first voltage range is first increasing and then decreasing.

[0491] The second control module 1920 is used to perform perturbation processing on the operating voltage of the photovoltaic module within the first voltage range to obtain a first power point, wherein the first power point meets the maximum power point requirement corresponding to the photovoltaic module.

[0492] The second control module 1920 is used to control the operation of the photovoltaic module based on the first operating voltage corresponding to the first power point.

[0493] In some embodiments, the first control module 1910 is configured to: acquire the i-th operating voltage; control the photovoltaic module to operate based on the i-th operating voltage to obtain the i-th power point; perform the i-th voltage boosting operation on the i-th operating voltage to obtain the (i+1)-th operating voltage; control the photovoltaic module to operate based on the (i+1)-th operating voltage to obtain the (i+1)-th power point; wherein the boosted voltage corresponding to the i-th voltage boosting operation is determined by the reference voltage corresponding to the first scan step size; wherein the (i+1)-th operating voltage is the sum of the i-th operating voltage and the boosted voltage corresponding to the i-th voltage boosting operation, and i is a positive integer.

[0494] In some embodiments, the first control module 1910 is configured to: perform the first curve scanning process on the photovoltaic module; and, if the photovoltaic module meets the first scan completion condition, stop the first curve scanning process to obtain the power points corresponding to at least three operating voltages of the photovoltaic module; the first scan completion condition includes at least one of the following:

[0495] The current operating voltage of the photovoltaic module is lower than the minimum operating voltage of the photovoltaic module;

[0496] The current operating current of the photovoltaic module is greater than the maximum operating current of the photovoltaic module;

[0497] The operating voltage setting value is less than the minimum operating voltage of the photovoltaic module;

[0498] The output power of the photovoltaic module is greater than the maximum output power of the photovoltaic module;

[0499] The DC bus voltage is greater than the highest bus voltage;

[0500] The output power corresponding to the current operating voltage of the photovoltaic module is less than the output power corresponding to the previous operating voltage of the photovoltaic module.

[0501] In some embodiments, the first control module 1910 is configured to: determine that the operating voltage corresponding to the maximum power point among the at least three power points is less than or equal to the minimum voltage corresponding to the first voltage range when the power change trend corresponding to the at least three power points is monotonically increasing; and determine the first voltage range within the voltage range corresponding to the at least three power points when the power change trend corresponding to the at least three power points is first increasing and then decreasing.

[0502] In some embodiments, the perturbation processing includes at least two perturbation operations; the second control module 1920 is configured to: perform a j-th perturbation operation on the j-th operating voltage of the photovoltaic module based on the j-th perturbation direction and the j-th perturbation step size to obtain the (j+1)-th operating voltage; control the operation of the photovoltaic module based on the (j+1)-th operating voltage to obtain the (j+1)-th output power; j is a positive integer; if the (j+1)-th output power meets the maximum power point requirement, take the (j+1)-th output power as the first power point; if the (j+1)-th output power does not meet the maximum power point requirement, determine the (j+1)-th perturbation direction and the (j+1)-th perturbation step size based on the difference between the (j+1)-th output power and the j-th output power; and continue to perform the perturbation processing based on the (j+1)-th perturbation direction and the (j+1)-th perturbation step size to obtain the first power point.

[0503] In some embodiments, the second control module 1920 is configured to: when the j-th disturbance direction is positive, add a reference voltage corresponding to the j-th disturbance step size to the j-th operating voltage to obtain the (j+1)-th operating voltage; and when the j-th disturbance direction is negative, reduce the reference voltage corresponding to the j-th disturbance step size to the j-th operating voltage to obtain the (j+1)-th operating voltage.

[0504] In some embodiments, the second control module 1920 is configured to: determine a (j+1)th disturbance value based on a first power difference between the (j+1)th output power and the jth output power; determine the (j+1)th disturbance direction as positive if the (j+1)th disturbance value is greater than or equal to a first preset value; determine the (j+1)th disturbance direction as negative if the (j+1)th disturbance value is less than the first preset value; obtain a first voltage difference between the (j+1)th operating voltage and the jth operating voltage; determine a first ratio between the (j+1)th disturbance value and the first voltage difference; and determine the (j+1)th disturbance step size based on the disturbance coefficient and the first ratio.

[0505] In some embodiments, the perturbation process includes at least two perturbation operations; the maximum power point requirement includes at least one of the following:

[0506] After N consecutive perturbation operations, the absolute value of the power difference between the current output power of the photovoltaic module and the previous output power of the photovoltaic module is less than a first power threshold; N is an integer greater than 1.

[0507] After N consecutive perturbation operations, the absolute value of the voltage difference between the current operating voltage of the photovoltaic module and the previous operating voltage of the photovoltaic module is less than a first voltage threshold.

[0508] In some embodiments, the first control module 1910 is configured to: perform a second curve scanning process on the photovoltaic module when the current moment is in a first scanning cycle, wherein the second curve scanning process is used to control the operating voltage of the photovoltaic module to gradually increase based on a second scanning step size; the second curve scanning process may be the same as or different from the first curve scanning process; determine a second voltage range based on the power point obtained by the second curve scanning process; the power change trend corresponding to the power point in the second voltage range is first increasing and then decreasing; the second control module 1920 is configured to: perform a disturbance processing on the operating voltage of the photovoltaic module within the second voltage range to obtain a second power point, wherein the second power point meets the maximum power point requirement corresponding to the photovoltaic module; and control the operation of the photovoltaic module based on the second operating voltage corresponding to the second power point.

[0509] In some embodiments, the first control module 1910 is configured to: stop the second curve scanning process when the photovoltaic module meets the second scan completion condition, and determine a second voltage range based on the power point obtained by the second curve scanning process; the second scan completion condition includes at least one of the following:

[0510] The voltage difference between the current operating voltage of the photovoltaic module and the maximum operating voltage of the photovoltaic module is greater than the first preset voltage;

[0511] The current operating current of the photovoltaic module is greater than the product of the maximum operating current of the photovoltaic module and the first current coefficient.

[0512] The current operating current of the photovoltaic module is less than the product of the minimum operating current of the photovoltaic module and the second current coefficient.

[0513] The output power of the photovoltaic module is greater than the product of the maximum output power of the photovoltaic module and the power coefficient.

[0514] In summary, the inverter-based control device provided in this application quickly locks down the approximate voltage range (i.e., the first voltage range) where the maximum power point is located by performing a first curve scan on the photovoltaic module and collecting multiple power points. Then, within the locked voltage range, the operating voltage of the photovoltaic module is perturbed to determine the first power point that meets the requirements of the maximum power point. Finally, the photovoltaic module is controlled to operate at the first operating voltage corresponding to the first power point. Since the perturbation is only performed within the locked small voltage range, the process of repeatedly adjusting within the entire voltage range of the photovoltaic module is avoided, significantly reducing the number of adjustments and time required to approach the maximum power point, improving the speed of tracking the maximum power point, and thus improving the power generation efficiency of the photovoltaic power generation system.

[0515] It should be noted that the specific limitations of the one or more inverter-based control device embodiments provided above can be found in the limitations of the inverter-based control method above, and will not be repeated here. Each module of the above device can be implemented entirely or partially through software, hardware, or a combination thereof. Each module can be embedded in the processor of the computer device in hardware form or independent of the processor, or stored in the memory of the computer device in software form, so that the processor can call and execute the corresponding operations of each module.

[0516] Figure 20 This is a structural block diagram of a controller provided in an embodiment of this application. See also... Figure 20 The controller 2000 includes a processor 2010 and a memory 2020; the memory 2020 stores at least one program, which is loaded and executed by the processor 2010 to implement any of the inverter-based control methods described above. As an example, the processor 2010 may be one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), controllers, microcontrollers, microprocessors, or other electronic components. The controller 2000 is a controller in an inverter.

[0517] This application embodiment also provides a computer-readable storage medium, which is a non-volatile storage medium, and the storage medium stores at least one program of a processor, which is configured to cause the processor to implement any of the above-described inverter-based control methods when executed by the processor.

[0518] Figure 21 This is a structural block diagram of an inverter provided in an embodiment of this application. See also... Figure 21The inverter 2100 includes a controller 2110 and an inverter circuit 2120 connected to the controller 2110. The inverter 2100 includes a photovoltaic inverter.

[0519] Figure 22 This is a structural block diagram of a photovoltaic device provided in an embodiment of this application. See also... Figure 22 In one example, the photovoltaic device 2200 includes at least one set of photovoltaic modules 2210 and inverters 2220 connected to each other. The inverters 2220 are any of the inverters described above. The inverters 2220 are capable of converting the direct current output from the photovoltaic modules 2210 into alternating current for output to the power grid or loads (such as electrical equipment).

[0520] Figure 23 This is a structural block diagram of a photovoltaic power generation system provided in an embodiment of this application. See also... Figure 23 The photovoltaic power generation system 2300 includes: grid / load 2301, inverter 2302, and inverter 2302 includes multiple MPPT controllers and photovoltaic modules PV connected to the multiple MPPT controllers respectively. Figure 23 The display shows m MPPT controllers, where m is an integer greater than 1.

[0521] The photovoltaic (PV) power generation system 2300 is a system that directly converts sunlight into electrical energy using photovoltaic (PV) modules. The grid / load 2301 is the output terminal of the PV power generation system, which can be the power grid or a directly connected load (such as a household appliance). The electrical energy generated by the PV power generation system 2300 is converted into alternating current (AC) by an inverter, which can then directly supply these loads or be connected to the grid. The inverter 2302 converts the direct current (DC) generated by the PV modules into alternating current (AC) for use by the power grid or loads. Optionally, the inverter 1302 can be implemented as any of the inverters shown above. An MPPT controller is used to maximize the power output of the PV modules. Each MPPT controller is connected to a group of PV modules, and the MPPT controller adjusts the voltage or current to ensure that the PV modules always operate at their maximum power point. The PV modules can be implemented as solar cells.

[0522] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0523] Those skilled in the art will understand that all or part of the steps of the above embodiments can be implemented by hardware or by a program instructing related hardware. The program can be stored in a computer-readable storage medium, such as a read-only memory, a disk, or an optical disk.

[0524] Those skilled in the art will recognize that the functions described in the embodiments of this application in one or more of the above examples can be implemented using hardware, software, firmware, or any combination thereof. When implemented using software, these functions can be stored in a computer-readable medium or transmitted as one or more instructions or code on a computer-readable medium. Computer-readable media include computer storage media and communication media, wherein communication media include any medium that facilitates the transfer of a computer program from one place to another. Storage media can be any available medium that can be accessed by a general-purpose or special-purpose computer.

[0525] The above description is merely an optional embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A control method based on an inverter, characterized in that, The inverter is connected to the photovoltaic module; the method includes: The photovoltaic module is subjected to a first curve scanning process to obtain power points corresponding to at least three operating voltages of the photovoltaic module, wherein the power points indicate the output power of the photovoltaic module at the corresponding operating voltage; the first curve scanning process is used to control the operating voltage of the photovoltaic module to be gradually increased based on a first scanning step size; A first voltage range is determined based on at least three power points, wherein the power change trend corresponding to the power points within the first voltage range is first increasing and then decreasing. Within the first voltage range, the operating voltage of the photovoltaic module is perturbed to obtain a first power point, which meets the maximum power point requirement of the photovoltaic module. The photovoltaic module is controlled to operate based on the first operating voltage corresponding to the first power point.

2. The method according to claim 1, characterized in that, The first curve scanning process performed on the photovoltaic module to obtain the power points corresponding to at least three operating voltages of the photovoltaic module includes: Obtain the i-th operating voltage; control the operation of the photovoltaic module based on the i-th operating voltage to obtain the i-th power point; The i-th operating voltage is subjected to the i-th voltage boosting operation to obtain the (i+1)-th operating voltage; the photovoltaic module is controlled to operate based on the (i+1)-th operating voltage to obtain the (i+1)-th power point; the boosting voltage corresponding to the i-th voltage boosting operation is determined by the reference voltage corresponding to the first scan step size; Wherein, the (i+1)th working voltage is the sum of the ith working voltage and the boost voltage corresponding to the ith voltage boost operation, and i is a positive integer.

3. The method according to claim 1, characterized in that, The first curve scanning process performed on the photovoltaic module to obtain the power points corresponding to at least three operating voltages of the photovoltaic module includes: The first curve scan process is performed on the photovoltaic module; If the photovoltaic module meets the first scan completion condition, the first curve scan process is stopped, and the power points corresponding to at least three operating voltages of the photovoltaic module are obtained; the first scan completion condition includes at least one of the following: The current operating voltage of the photovoltaic module is lower than the minimum operating voltage of the photovoltaic module; The current operating current of the photovoltaic module is greater than the maximum operating current of the photovoltaic module; The operating voltage setting value is less than the minimum operating voltage of the photovoltaic module; The output power of the photovoltaic module is greater than the maximum output power of the photovoltaic module; The DC bus voltage is greater than the highest bus voltage; The output power corresponding to the current operating voltage of the photovoltaic module is less than the output power corresponding to the previous operating voltage of the photovoltaic module.

4. The method according to any one of claims 1 to 3, characterized in that, Determining the first voltage range based on at least three power points includes: When the power change trend corresponding to the at least three power points is monotonically increasing, the operating voltage corresponding to the maximum power point among the at least three power points is determined to be less than or equal to the minimum voltage corresponding to the first voltage range. If the power change trend corresponding to the at least three power points is first increasing and then decreasing, the first voltage range is determined within the voltage range corresponding to the at least three power points.

5. The method according to any one of claims 1 to 3, characterized in that, The perturbation process includes at least two perturbation operations; The step of performing perturbation processing on the operating voltage of the photovoltaic module within the first voltage range to obtain the first power point includes: Based on the j-th perturbation direction and the j-th perturbation step size, the j-th perturbation operation is performed on the j-th operating voltage of the photovoltaic module to obtain the (j+1)-th operating voltage; the photovoltaic module is controlled to operate based on the (j+1)-th operating voltage to obtain the (j+1)-th output power; j is a positive integer; If the (j+1)th output power meets the maximum power point requirement, the (j+1)th output power is taken as the first power point; If the (j+1)th output power does not meet the maximum power point requirement, the (j+1)th perturbation direction and the (j+1)th perturbation step size are determined based on the difference between the (j+1)th output power and the jth output power; based on the (j+1)th perturbation direction and the (j+1)th perturbation step size, the perturbation processing is continued to obtain the first power point.

6. The method according to claim 5, characterized in that, The step of determining the (j+1)th perturbation direction and the (j+1)th perturbation step size based on the difference between the (j+1)th output power and the jth output power includes: The (j+1)th disturbance value is determined based on the first power difference between the (j+1)th output power and the jth output power; If the (j+1)th disturbance value is greater than or equal to a first preset value, the (j+1)th disturbance direction is determined to be a positive direction; if the (j+1)th disturbance value is less than the first preset value, the (j+1)th disturbance direction is determined to be a negative direction. Obtain the first voltage difference between the (j+1)th operating voltage and the jth operating voltage; determine the first ratio between the (j+1)th disturbance value and the first voltage difference; and determine the (j+1)th disturbance step size based on the disturbance coefficient and the first ratio.

7. The method according to any one of claims 1 to 3, characterized in that, The perturbation process includes at least two perturbation operations; the maximum power point requirement includes at least one of the following: After N consecutive perturbation operations, the absolute value of the power difference between the current output power of the photovoltaic module and the previous output power of the photovoltaic module is less than a first power threshold; N is an integer greater than 1. After N consecutive perturbation operations, the absolute value of the voltage difference between the current operating voltage of the photovoltaic module and the previous operating voltage of the photovoltaic module is less than a first voltage threshold.

8. The method according to any one of claims 1 to 3, characterized in that, After performing perturbation processing on the operating voltage of the photovoltaic module within the first voltage range, the method further includes: While the photovoltaic module is in the first scan cycle at the current moment, a second curve scan process is performed on the photovoltaic module. The second curve scan process is used to control the operating voltage of the photovoltaic module to gradually increase based on a second scan step size. The second curve scan process may be the same as or different from the first curve scan process. The second voltage range is determined based on the power points obtained from the second curve scanning process; the power change trend corresponding to the power points within the second voltage range is first increasing and then decreasing. Within the second voltage range, the operating voltage of the photovoltaic module is perturbed to obtain a second power point, which meets the maximum power point requirement of the photovoltaic module. The photovoltaic module is controlled to operate based on the second operating voltage corresponding to the second power point.

9. The method according to claim 8, characterized in that, The step of determining the second voltage range based on the power point obtained from the second curve scanning process includes: If the photovoltaic module meets the second scan completion condition, the second curve scan process is stopped, and a second voltage range is determined based on the power point obtained from the second curve scan process; the second scan completion condition includes at least one of the following: The voltage difference between the current operating voltage of the photovoltaic module and the maximum operating voltage of the photovoltaic module is greater than the first preset voltage; The current operating current of the photovoltaic module is greater than the product of the maximum operating current of the photovoltaic module and the first current coefficient. The current operating current of the photovoltaic module is less than the product of the minimum operating current of the photovoltaic module and the second current coefficient. The output power of the photovoltaic module is greater than the product of the maximum output power of the photovoltaic module and the power coefficient.

10. An inverter, characterized in that, The inverter includes a controller for executing the inverter-based control method as described in any one of claims 1 to 9; the inverter includes a photovoltaic inverter.

11. A photovoltaic device, characterized in that, The photovoltaic device includes at least one set of interconnected inverters and photovoltaic modules; the inverter is the inverter as described in claim 10.

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