Photovoltaic system, photovoltaic string identification method, electronic device and storage medium

Abstract

The present invention provides a photovoltaic system, a photovoltaic string identification method, an electronic device and a storage medium, and relates to the field of photovoltaic technology. The system includes multiple photovoltaic strings, an inverter, and a central controller. Each photovoltaic string includes at least three photovoltaic units, each photovoltaic unit is equipped with a STA, and the photovoltaic unit is used to convert the radiation energy of sunlight into direct current; the inverter is connected to multiple photovoltaic strings, and is used to convert the direct current output by the photovoltaic unit into alternating current and output it. The present invention constructs an efficient and accurate photovoltaic system by introducing multiple photovoltaic strings, inverters, central controllers and other components. The system uses the STA on the photovoltaic unit to send and receive power carrier signals, and by comparing the signal strength, it can quickly and accurately determine the string relationship between photovoltaic units without relying on complex attenuation thresholds.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic technology, and in particular to a photovoltaic system, a photovoltaic string identification method, an electronic device and a storage medium. Background Art

[0002] The photovoltaic system is a power generation system that directly converts solar energy into electrical energy. The photovoltaic system generally includes photovoltaic strings connected in series by photovoltaic units and inverters. In the actual deployment of the photovoltaic system, in order to improve the efficiency of energy conversion and the convenience of management, the photovoltaic units are usually deployed as different photovoltaic strings. The photovoltaic units in the same photovoltaic string are connected in series, and different strings are connected to the inverter respectively. After the photovoltaic system is installed, the deployment mode information needs to be input into the central controller to facilitate the central controller to manage the photovoltaic units of different photovoltaic strings. As the scale of the photovoltaic system expands, the number of photovoltaic units included in the photovoltaic system increases, and the corresponding strings also increase. Therefore, how to efficiently and accurately confirm the string information of the photovoltaic unit is an urgent problem to be solved. Summary of the invention

[0003] To this end, embodiments of the present invention provide a photovoltaic system, a photovoltaic string identification method, an electronic device and a storage medium, which are used to solve the problem in the prior art of how to efficiently and accurately confirm the string information of photovoltaic units when the scale of the photovoltaic system is expanded so that the central controller can effectively manage and optimize the control.

[0004] In order to solve the above problems, an embodiment of the present invention provides a photovoltaic system, which includes a plurality of photovoltaic strings, an inverter, and a central controller; the photovoltaic strings are respectively connected to the inverter and the central controller, the inverter is used to convert the direct current output by the photovoltaic strings into alternating current and output it, and the central controller is used to monitor and adjust the photovoltaic strings; each of the photovoltaic strings includes at least three photovoltaic units, each of the photovoltaic units includes an STA and one or more photovoltaic modules connected to the STA, and the photovoltaic modules are used to convert the radiation energy of sunlight into direct current;

[0005] The STA of each photovoltaic unit is used to receive the first power carrier signal of the same signal strength sent by the STA of other photovoltaic units, and compare the received signal strengths to obtain the first STA identification information with the strongest signal strength and its corresponding first signal strength value, as well as the second STA identification information with the second strongest signal strength and its corresponding second signal strength value; wherein, the first power carrier signal includes the identification information of the STA that sends the first power carrier signal, the first STA identification information refers to the identification information of the STA corresponding to the strongest signal strength in the received signal, and the second STA identification information refers to the identification information of the STA corresponding to the second strongest signal strength in the received signal;

[0006] The STA of each photovoltaic unit is also used to send a second power carrier signal to the central controller; wherein the second power carrier signal includes the identification information of the STA sending the second power carrier signal, and the first STA identification information and the second STA identification information obtained by the STA;

[0007] The central controller is further configured to receive the second power carrier signal sent by the STA of each photovoltaic unit, and determine the photovoltaic string to which each photovoltaic unit belongs according to the identification information therein.

[0008] Preferably, the central controller is used to receive the second power carrier signal sent by the STA of each photovoltaic unit, and determine the photovoltaic string to which each photovoltaic unit belongs according to the identification information therein, specifically for:

[0009] If a second power carrier signal and another second power carrier signal have the same identification information, then the photovoltaic units corresponding to all the identification information contained in the corresponding two second power carrier signals are the same photovoltaic string.

[0010] Preferably, the central controller is used to receive the second power carrier signal sent by the STA of each photovoltaic unit, and determine the photovoltaic string to which each photovoltaic unit belongs according to the identification information therein, specifically for:

[0011] If the second power carrier signal sent by the STA of a certain photovoltaic unit and the second power carrier signal sent by the STA of another photovoltaic unit have at least two identical identification information, the corresponding two photovoltaic units are the same photovoltaic string.

[0012] Preferably, the central controller is further used to count the number of occurrences of each identification information in the second power carrier signal of each photovoltaic string, and determine the starting photovoltaic unit or the ending photovoltaic unit corresponding to each photovoltaic string according to the statistical result.

[0013] Preferably, the central controller is used to determine the starting photovoltaic unit or the ending photovoltaic unit corresponding to each photovoltaic string according to the statistical results, specifically for:

[0014] According to the statistical results, if a certain identification information appears twice, the photovoltaic unit corresponding to the certain identification information is a starting end photovoltaic unit or an ending end photovoltaic unit.

[0015] An embodiment of the present invention provides a photovoltaic string identification method, which is applied to a photovoltaic system, wherein the photovoltaic system includes a plurality of photovoltaic strings, an inverter, and a central controller; the photovoltaic strings are respectively connected to the inverter and the central controller, the inverter is used to convert the direct current output by the photovoltaic strings into alternating current and output it, and the central controller is used to monitor and adjust the photovoltaic strings; each of the photovoltaic strings includes at least three photovoltaic units, the photovoltaic units include an STA and one or more photovoltaic modules connected to the STA, and the photovoltaic modules are used to convert solar energy into direct current; the method includes:

[0016] The STA of each photovoltaic unit sends a first power carrier signal with the same signal strength; wherein the first power carrier signal includes identification information of the STA sending the first power carrier signal;

[0017] The STA of each photovoltaic unit receives the first power carrier signal sent by the STA of other photovoltaic units, and compares the received signal strengths to obtain the first STA identification information with the strongest signal strength and its corresponding first signal strength value, as well as the second STA identification information with the second strongest signal strength and its corresponding second signal strength value; wherein the first STA identification information refers to the identification information of the STA corresponding to the strongest signal strength in the received signal, and the second STA identification information refers to the identification information of the STA corresponding to the second strongest signal strength in the received signal;

[0018] The STA of each photovoltaic unit sends a second power carrier signal to the central controller; wherein the second power carrier signal includes the identification information of the STA sending the second power carrier signal, and the first STA identification information and the second STA identification information obtained by the STA;

[0019] The central controller receives the second power carrier signal sent by the STA of each photovoltaic unit, and determines the photovoltaic string to which each photovoltaic unit belongs according to the identification information therein.

[0020] Preferably, determining the photovoltaic string to which each photovoltaic unit belongs according to the identification information thereof includes:

[0021] If a second power carrier signal and another second power carrier signal have the same identification information, then the photovoltaic units corresponding to all the identification information contained in the corresponding two second power carrier signals are the same photovoltaic string.

[0022] Preferably, the determining the photovoltaic string to which each photovoltaic unit belongs according to the identification information thereof includes:

[0023] If the second power carrier signal sent by the STA of a certain photovoltaic unit and the second power carrier signal sent by the STA of another photovoltaic unit have at least two identical identification information, the corresponding two photovoltaic units are the same photovoltaic string.

[0024] Preferably, the method further comprises:

[0025] The central controller counts the number of occurrences of each identification information in the second power carrier signal of each photovoltaic string, and determines the starting photovoltaic unit or the ending photovoltaic unit corresponding to each photovoltaic string according to the statistical result.

[0026] Preferably, the step of determining the starting photovoltaic unit or the ending photovoltaic unit corresponding to each photovoltaic string according to the statistical results specifically includes:

[0027] According to the statistical results, if a certain identification information appears twice, the photovoltaic unit corresponding to the certain identification information is a starting end photovoltaic unit or an ending end photovoltaic unit.

[0028] An embodiment of the present invention further provides an electronic device, comprising a processor, a memory and a bus system, wherein the processor and the memory are connected via the bus system, the memory is used to store instructions, and the processor is used to execute the instructions stored in the memory to implement the above-mentioned photovoltaic string identification method.

[0029] An embodiment of the present invention further provides a computer storage medium, wherein the computer storage medium stores a computer software product, wherein the computer software product includes several instructions for enabling a computer device to execute the above-mentioned photovoltaic string identification method.

[0030] It can be seen from the above technical solutions that the present invention has the following beneficial effects:

[0031] (1) High accuracy: The present invention determines the string relationship between photovoltaic units by directly comparing the strength of the received power carrier signal, without setting and relying on complex attenuation thresholds. Since the attenuation threshold is affected by many factors (such as the strength of the transmitted signal, the length of the power line, the system layout environment, etc.), its setting is often not accurate enough, which can easily lead to errors in string judgment. The present invention only compares the signal strength, avoiding the interference of these external factors and improving the accuracy of judgment.

[0032] (2) High efficiency: Traditional string identification methods require complex calculation and judgment processes, while the present invention is simple and direct. It can quickly determine the string relationship of photovoltaic units by simply comparing signal strength, greatly improving the operating efficiency of the system.

[0033] (3) Wide applicability: The present invention does not rely on specific system layout or environmental factors and is applicable to photovoltaic system layouts in various situations. Regardless of the size of the photovoltaic system, the length of the power line, and the layout environment, the method of the present invention can effectively perform string identification.

[0034] (4) High reliability: The present invention can couple the power carrier signal transmitted between photovoltaic units through power lines by introducing a magnetic ring, thereby improving the transmission quality and stability of the signal and further enhancing the reliability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the implementation cases of the present invention or the technical solutions in the prior art, the following is a brief description of the drawings required for use in the embodiments. By referring to the drawings, the features and advantages of the present invention will be more clearly understood. The drawings are schematic and should not be understood as limiting the present invention in any way. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

[0036] Figure 1 A schematic diagram of the structure of a photovoltaic system provided in an embodiment;

[0037] Figure 2 A schematic structural diagram of a photovoltaic system including five photovoltaic units provided in an embodiment;

[0038] Figure 3 The figure is a flow chart of a photovoltaic string identification method provided in an embodiment. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Embodiment 1

[0040] In order to solve the problem in the prior art of how to efficiently and accurately confirm the string information of photovoltaic units when the scale of photovoltaic systems is expanded, so that the central controller can effectively manage and optimize the control. Figure 1As shown, an embodiment of the present invention proposes a photovoltaic system, which includes a central controller, multiple photovoltaic strings, inverters, etc.; the photovoltaic string is composed of multiple photovoltaic units connected in series, and the photovoltaic unit includes a station module (STA) and one or more photovoltaic modules connected to the STA. The STA is used to monitor or optimize the parameters of the photovoltaic modules. The STA can be a photovoltaic monitor or a photovoltaic optimizer; the inverter is used to convert the direct current generated by the photovoltaic string into alternating current. The central controller is connected to the photovoltaic string and the inverter, and is used to collect the operating status and parameter information of the photovoltaic system in real time. The STAs communicate bidirectionally through power lines, and the STAs and the central controller communicate bidirectionally through power lines. The modules in the photovoltaic system work together through a specific connection method to achieve the operating efficiency and stability of the entire photovoltaic system.

[0041] In the embodiment of the present application, each photovoltaic string includes at least three photovoltaic units, each photovoltaic unit includes a STA and one or more photovoltaic modules connected to the STA, and the photovoltaic modules are used to convert the radiation energy of sunlight into direct current;

[0042] The STA of each photovoltaic unit is used to receive the first power carrier signal of the same signal strength sent by the STA of other photovoltaic units, and compare the received signal strengths to obtain the first STA identification information with the strongest signal strength and its corresponding first signal strength value, as well as the second STA identification information with the second strongest signal strength and its corresponding second signal strength value. The first power carrier signal includes the identification information of the STA that sends the first power carrier signal, where the identification information of the STA can be the logical address, media access control address (MAC) address or STA serial number of the STA. Each photovoltaic unit has unique identification information, and the identification information of different photovoltaic units is different. The first STA identification information refers to the identification information of the STA corresponding to the strongest signal strength in the received signal. The second STA identification information refers to the identification information of the STA corresponding to the second strongest signal strength in the received signal.

[0043] The STA of each photovoltaic unit is also used to send a second power carrier signal to the central controller, wherein the second power carrier signal includes the STA identification information sending the second power carrier signal, and the first STA identification information and the second STA identification information obtained by the STA;

[0044] The central controller is connected to the photovoltaic strings and is used to receive the second power carrier signal sent by the photovoltaic units on all photovoltaic strings, and determine the photovoltaic string to which each photovoltaic unit belongs according to the identification information therein.

[0045] Specifically, in the embodiment of the present application, the central controller includes a magnetic ring, which is coupled to the power line of the photovoltaic string, and then the central controller can receive or send signals by inductive coupling of the magnetic ring. The magnetic ring further enhances the reliability and coverage of signal transmission, so that the system can operate stably in various environments.

[0046] From the above technical solution, it can be seen that the present invention provides a photovoltaic system, which constructs an efficient and accurate photovoltaic system by introducing multiple photovoltaic strings, inverters, central controllers and other components. The system uses the STA on the photovoltaic unit to send and receive power carrier signals, and by comparing the signal strength, it can quickly and accurately determine the string relationship between photovoltaic units without relying on complex attenuation thresholds. In addition, through the centralized management of the central controller, efficient monitoring and management of photovoltaic strings are achieved, thereby improving the performance and reliability of the entire photovoltaic system.

[0047] Figure 1 A schematic diagram of a photovoltaic system provided in an embodiment of the present application. The photovoltaic system is used to convert the radiation energy of sunlight into electrical energy. Figure 1 As shown in the figure, A1, A2 to An are photovoltaic units, belonging to one photovoltaic string, and B1, B2 to Bn are also photovoltaic units, belonging to another photovoltaic string. The upper side is the central controller, and the connecting part is the magnetic ring, which is mounted on the photovoltaic string. Among them, the photovoltaic unit is installed with a STA (monitor or optimizer) to support the power line bidirectional data transmission function; the central controller (also supports the power line bidirectional data transmission function, the inverter is connected to the photovoltaic string, and its function is to convert the DC power generated by the photovoltaic unit into AC power.

[0048] It should be noted that although Figure 1 Only a photovoltaic system including two photovoltaic strings is shown in the figure, but the number of photovoltaic strings can be set according to actual needs, and the photovoltaic system can include multiple photovoltaic strings. A photovoltaic string includes multiple photovoltaic units (including at least three photovoltaic units). Multiple photovoltaic units in the same photovoltaic string are connected in series to form a DC high-voltage string, which is connected to an inverter. The inverter is used to convert the DC power output by the photovoltaic unit into AC power and input the AC power into the grid.

[0049] Optionally, the photovoltaic unit includes a photovoltaic module and STA, the photovoltaic module may be a solar panel, and the STA may adjust the output power (voltage amplitude and current amplitude of direct current) of the photovoltaic module so that the output power of the photovoltaic module reaches a maximum power to improve the utilization rate of the photovoltaic module.

[0050] In this embodiment, the central controller is also used to count the number of times each identification information appears in the second power carrier signal of each photovoltaic string, and determine the starting photovoltaic unit or the ending photovoltaic unit corresponding to each photovoltaic string according to the statistical results.

[0051] Specifically, according to the statistical results, if a certain identification information appears twice, the photovoltaic unit corresponding to the certain identification information is the starting end photovoltaic unit or the ending end photovoltaic unit.

[0052] In this embodiment, the central controller is further configured to generate a unique string identification code for each determined photovoltaic string, and send the string identification code to each photovoltaic unit so that the photovoltaic unit can identify the photovoltaic string to which it belongs.

[0053] In this embodiment, the STA of each photovoltaic unit is used to receive the first power carrier signal with the same signal strength sent by the STA of other photovoltaic units, and compare the received signal strengths to obtain the first STA identification information with the strongest signal strength and its corresponding first signal strength value, as well as the second STA identification information with the second strongest signal strength and its corresponding second signal strength value, specifically used for:

[0054] The STA of each photovoltaic unit receives the first power carrier signal with the same signal strength sent by the STA of other photovoltaic units;

[0055] Compare the signal strength of each received first power carrier signal, identify and record the identification information of the first STA with the strongest signal strength and its corresponding signal strength value, and at the same time, identify and record the identification information of the second STA with the second strongest signal strength and its corresponding signal strength value;

[0056] When a new first power carrier signal is received, the signal strength of the new signal is compared with the currently recorded first signal strength and second signal strength;

[0057] If the signal strength of the new signal is greater than the first signal strength and the second signal strength, the first STA identification information and its corresponding first signal strength value are updated, and the second STA identification information and its corresponding second signal strength value are updated at the same time, that is, the original first STA identification information becomes the second STA identification information, and the STA identification information corresponding to the new signal becomes the first STA identification information;

[0058] If the signal strength of the new signal is between the first signal strength and the second signal strength, the second STA identification information and its corresponding second signal strength value are updated, that is, the STA identification information corresponding to the new signal is changed to the second STA identification information;

[0059] If the signal strength of the new signal is less than or equal to the second signal strength currently recorded, no update is performed.

[0060] In this embodiment, the central controller is used to receive the second power carrier signal sent by the STA of all photovoltaic units, and determine the photovoltaic string to which each photovoltaic unit belongs based on the identification information therein. As an optional specific implementation, if a second power carrier signal and a second power carrier signal of another photovoltaic unit contain the same identification information, then the photovoltaic units corresponding to all the identification information contained in the two second power carrier signals are the same photovoltaic string. As an optional specific implementation, if at least two STA identification information in the second power carrier signal sent by the STA of a photovoltaic unit and the second power carrier signal sent by the STA of another photovoltaic unit are the same, then the two photovoltaic units are determined to be the same photovoltaic string. Embodiment 2

[0061] Combine the following Figure 2 , the implementation process of the method for identifying photovoltaic strings in a photovoltaic system provided in an embodiment of the present application is described. The working process of each device in the photovoltaic system can refer to the working process of the corresponding device in the embodiment of the method. Figure 3 A flow chart of a photovoltaic string identification method provided in an embodiment of the present application. Figure 3 As shown, the method includes:

[0062] Step S1: The STA of each photovoltaic unit sends a first power carrier signal with the same signal strength; wherein the first power carrier signal includes identification information of the STA sending the first power carrier signal;

[0063] Step S2: The STA of each photovoltaic unit receives the first power carrier signal sent by the STA of other photovoltaic units, and compares the received signal strengths to obtain the first STA identification information with the strongest signal strength and its corresponding first signal strength value, as well as the second STA identification information with the second strongest signal strength and its corresponding second signal strength value; wherein the first STA identification information refers to the identification information of the STA corresponding to the strongest signal strength in the received signal, and the second STA identification information refers to the identification information of the STA corresponding to the second strongest signal strength in the received signal;

[0064] Step S3: The STA of each photovoltaic unit sends a second power carrier signal to the central controller; wherein the second power carrier signal includes the identification information of the STA sending the second power carrier signal, and the first STA identification information and the second STA identification information obtained by the STA;

[0065] Step S4: the central controller receives the second power carrier signal sent by the STA of each photovoltaic unit, and determines the photovoltaic string to which each photovoltaic unit belongs according to the identification information therein.

[0066] It can be seen from the above technical solution that the present invention provides a photovoltaic string identification method, which sends and receives power carrier signals between photovoltaic units and uses the comparison of signal strength to determine the string relationship between each other, which has significant advantages. This method not only simplifies the process of photovoltaic string identification, but also improves the accuracy of identification. Compared with the traditional method based on attenuation threshold, the present invention does not need to consider factors such as the strength of the transmitted signal, the length of the power line, and the layout environment. It can quickly and accurately identify the photovoltaic string to which the photovoltaic unit belongs only by directly comparing the signal strength, which greatly improves the efficiency and stability of the photovoltaic system operation.

[0067] In step S1, the photovoltaic units in each photovoltaic string send a first power carrier signal of the same signal strength through their STA, wherein the first power carrier signal includes identification information of the STA that sends the first power carrier signal. The first power carrier signal of the same signal strength can be controlled by controlling the transmission power of the STA, that is, the STAs of all photovoltaic strings send power carrier signals with the same transmission power. As an optional specific implementation, the photovoltaic units may send the first power carrier signal in sequence by broadcasting, and the specific transmission order may be determined according to actual needs. As an optional specific implementation, the photovoltaic unit may send the first power carrier signal to the central controller, and other photovoltaic units may obtain the first power carrier signal by monitoring. It should be noted that when a photovoltaic unit is sending the first power carrier signal, other photovoltaic units may obtain the first power carrier signal being sent.

[0068] In step S2, the STA of each photovoltaic unit receives the first power carrier signal sent by the STA of other photovoltaic units, and compares the received signal strengths to obtain the first STA identification information with the strongest signal strength and its corresponding first signal strength value, as well as the second STA identification information with the second strongest signal strength and its corresponding second signal strength value. It should be noted that the signal strength of the received signal reflects the strength of the received signal. In power carrier communication, the signal strength is determined by the received signal power, and its calculation formula is: RSSI=10lgP, where RSSI represents signal strength, and dB is often used as a unit of measurement; P is signal power, and the greater the signal power, the higher the signal strength. The signal power is determined by the PLC digital baseband algorithm and the analog front-end gain in the STA. The signal strength will attenuate with the transmission of the power line. The signal in the same group string is less interfered and lost during transmission, and the attenuation degree is relatively small; the signal transmission between different groups of photovoltaic units not only needs to pass through the power line, but also needs to be connected through the inverter or other equipment. Since the inverter or other equipment contains complex circuits and components, the signal will be greatly attenuated when passing through the inverter or other equipment.

[0069] Specifically, the STA of each photovoltaic unit will compare and update the first STA identification information with the strongest signal strength and its corresponding first signal strength value, and the second STA identification information with the second strongest signal strength and its corresponding second signal strength value in real time according to the strength of the received signal when receiving the first power carrier signal with the same signal strength sent by the STA of other photovoltaic units, specifically including:

[0070] The STA of each photovoltaic unit receives the first power carrier signal with the same signal strength sent by the STA of other photovoltaic units;

[0071] Compare the signal strength of each received first power carrier signal, identify and record the identification information of the first STA with the strongest signal strength and its corresponding signal strength value, and at the same time, identify and record the identification information of the second STA with the second strongest signal strength and its corresponding signal strength value;

[0072] When a new first power carrier signal is received, the signal strength of the new signal is compared with the currently recorded first signal strength and second signal strength;

[0073] If the signal strength of the new signal is greater than the first signal strength and the second signal strength, the first STA identification information and its corresponding first signal strength value are updated, and the second STA identification information and its corresponding second signal strength value are updated at the same time, that is, the original first STA identification information becomes the second STA identification information, and the STA identification information corresponding to the new signal becomes the first STA identification information;

[0074] If the signal strength of the new signal is between the first signal strength and the second signal strength, the second STA identification information and its corresponding second signal strength value are updated, that is, the STA identification information corresponding to the new signal is changed to the second STA identification information;

[0075] If the signal strength of the new signal is less than or equal to the second signal strength currently recorded, no update is performed.

[0076] In the photovoltaic system, since power line carrier communication (PLC) technology is used to transmit signals between different STAs, the signal strength will gradually attenuate as the transmission distance of the power line increases. For STAs in the same photovoltaic string, they are usually directly connected through short-distance cables or buses. This connection method makes the signal attenuation mainly depend on the relative position between the two - the closer the position, the smaller the attenuation; the farther the position, the greater the attenuation. But in general, the interference and loss of signal transmission in the same photovoltaic string are relatively small, and the attenuation is relatively light.

[0077] In contrast, the STA signal transmission between different PV strings not only has to cross the power line, but may also need to pass through the inverter or other electrical equipment, which contains complex circuits and components, which will significantly increase the signal attenuation. Therefore, the strongest signal received by a PV unit usually comes from the same PV string as the PV unit, and is likely to be emitted by adjacent or alternate PV units.

[0078] Specifically, the photovoltaic cells corresponding to the first signal strength value and the second signal strength value received by each photovoltaic cell are often adjacent to or interlaced with the cell (in most cases, they are adjacent, except at the head and tail of the photovoltaic string, where they may be interlaced). Therefore, the three photovoltaic cells are determined to be in the same photovoltaic string.

[0079] For example, as shown in Table 1 below, in a system including photovoltaic units A1 to A5 and B1 to B5, if the strongest signal received by photovoltaic unit A1 comes from A2 and A3, it can be inferred that A1, A2, and A3 are in the same photovoltaic string, and A2 and A3 are adjacent to A1. Similarly, if the strongest signal received by A3 comes from A2 and A4, it can also be confirmed that they are in the same photovoltaic string. Although A4 and A3 may not be directly adjacent, in actual applications, since the power lines of adjacent photovoltaic units in the same photovoltaic string are similar in length, the signal strength received by A3 from A4 will be greater than the signals of other non-adjacent units.

[0080] It should be noted that the above analysis is based on the direct relationship between signal attenuation and transmission distance and the connection method between devices, and assumes the consistency of power line length and physical location between photovoltaic units.

[0081] This application proposes an innovative method to determine whether three photovoltaic units belong to the same photovoltaic string by simply comparing signal strength. This method is simple and efficient and is widely applicable to various photovoltaic system layout scenarios. Compared with the commonly used method in the prior art to determine photovoltaic string information based on attenuation thresholds, this method has significant advantages.

[0082] The traditional method determines the connection relationship between photovoltaic units by setting the attenuation threshold. However, the determination of the attenuation threshold is affected by many factors, including the strength of the transmitted signal, the actual length of the power line in the system, the specific layout environment of the photovoltaic system, etc. The uncertainty and variability of these factors make the setting of the attenuation threshold complex and difficult to be accurate, which may lead to errors in the judgment of photovoltaic strings.

[0083] In contrast, the method proposed in the present invention only relies on direct comparison of signal strengths between photovoltaic units, without the need to set complex attenuation thresholds. By simply comparing the signal strengths received by each photovoltaic unit, it is possible to quickly and accurately determine which photovoltaic units belong to the same photovoltaic string. This method not only simplifies the operation process, but also improves the accuracy and efficiency of judgment, and is particularly suitable for photovoltaic system application scenarios that require high real-time performance and accuracy.

[0084] In summary, the present application determines the string relationship between a photovoltaic unit and adjacent photovoltaic units by comparing signal strengths, which not only avoids the judgment errors caused by improper attenuation threshold setting in traditional methods, but also simplifies and improves the efficiency of photovoltaic string identification.

[0085] Table 1

[0086]

[0087] In step S3, each photovoltaic unit sends a second power carrier signal to the central controller through its STA, wherein the second power carrier signal includes the STA identification information that sends the second power carrier signal, and the first STA identification information and the second STA identification information that it obtains.

[0088] In the embodiment of the present application, each photovoltaic unit can identify the other two photovoltaic units in the same photovoltaic string, and send the identification information of this string to the central controller. Specifically, when photovoltaic unit A1 determines that it belongs to the same photovoltaic string as A2 and A3, it will send information containing the identification of these three photovoltaic units (such as a1, a2, and a3) to the central controller. Similarly, photovoltaic unit A2 will also send identification information containing A1, A2, and A3 to the central controller. Similarly, after photovoltaic unit B1 determines that it belongs to the same photovoltaic string as B2 and B3, it will send identification information containing B1, B2, and B3 to the central controller.

[0089] In addition, in order to ensure the accuracy and reliability of the information, a checksum may be added or other data verification techniques may be used when sending the information so that the central controller can verify the information after receiving it.

[0090] In summary, by sending the identification information of the PV string to which each PV unit belongs to the central controller, the system can establish a clear PV string network topology diagram, providing strong support for subsequent PV system management, monitoring and maintenance.

[0091] In step S4, the central controller receives the second power carrier signal sent by the STA of each photovoltaic unit, and determines the photovoltaic string to which each photovoltaic unit belongs according to the identification information therein.

[0092] As an optional specific implementation manner, determining the photovoltaic string to which each photovoltaic unit belongs according to the identification information thereof includes:

[0093] If a second power carrier signal and another second power carrier signal have the same identification information, then the photovoltaic units corresponding to all the identification information contained in the corresponding two second power carrier signals are the same photovoltaic string.

[0094] Specifically, when the central controller receives multiple second power carrier signals and finds that two or more of the second power carrier signals contain the same identification information, it can be inferred that the photovoltaic units corresponding to all the identification information in these signals belong to the same photovoltaic string. For example, if the second power carrier signal sent by A1 contains identification information a1, a2, and a3, and the second power carrier signal sent by A4 contains identification information a4, a3, and a5, since both signals contain a3, it can be judged that the photovoltaic units corresponding to the identification information a1, a2, a3, a4, and a5 (i.e., A1, A2, A3, A4, and A5) belong to the same photovoltaic string. The key here is that each second power carrier signal not only contains the identification information of the photovoltaic unit that sends the signal, but may also contain the identification information of other photovoltaic units in the same photovoltaic string. Since the photovoltaic units in the photovoltaic string are connected in series, as long as there is common identification information in two or more second power carrier signals, it can be considered that the photovoltaic units corresponding to all the listed identification information in these signals belong to the same photovoltaic string.

[0095] The central controller is responsible for receiving and processing all second power carrier signals. It constructs the topological structure of the photovoltaic string by analyzing the identification information contained in the signal. As shown in Table 1, the central controller can determine that A1, A2, A3, A4, and A5 are the same photovoltaic string, B1, B2, B3, B4, and B5 are another photovoltaic string, and so on based on the received power carrier signal.

[0096] As an optional specific implementation manner, determining the photovoltaic string to which each photovoltaic unit belongs according to the identification information thereof includes:

[0097] If the second power carrier signal sent by the STA of a certain photovoltaic unit and the second power carrier signal sent by the STA of another photovoltaic unit have at least two identical identification information, the corresponding two photovoltaic units are the same photovoltaic string.

[0098] Specifically, if the second power carrier signal sent by the STA of a photovoltaic unit and the second power carrier signal sent by the STA of another photovoltaic unit contain at least two identical STA identification information, the two photovoltaic units are deemed to belong to the same photovoltaic string. For example, the second power carrier signal sent by A1 contains STA identification information a1, a2, and a3, and the second power carrier signal sent by A3 contains STA identification information a3, a2, and a4. Since the two share STA identification information a2 and a3, A1 and A3 are determined to be the same photovoltaic string. In this process, the central controller first analyzes the identification information in the power carrier signal, and then determines the group string affiliation of the photovoltaic unit based on this information.

[0099] In actual photovoltaic operation systems, due to the complex and changeable environment, the power carrier signal may be subject to various interferences, resulting in errors in the received information. For example, A3 should obtain STA identification information a2 and a4 under normal circumstances, but due to interference, it may mistakenly obtain a2 and b1, and send a power carrier signal containing a3, a2, and b1 accordingly. In this case, according to the judgment rule, A1 and A3 will still be regarded as the same photovoltaic string, because at least two STA identification information in their signals are the same, but A1, A2, A3, and B1 will not be judged as the same photovoltaic string, thereby avoiding the string determination error caused by the acquisition error in step S2, that is, avoiding the chain reaction caused by a single error. In particular, only when another photovoltaic unit (such as B1) also has a similar error, and its signal contains the same STA identification information (such as a3) as the error signal of A3, it is possible to mistakenly regard A3 and B1 as the same string. However, since the probability of this double error is low, the system can more reliably avoid such misjudgment.

[0100] By determining the string affiliation of PV units in this way, the topology of the PV system can be constructed more accurately and provide strong support for subsequent monitoring, management and maintenance.

[0101] As an optional specific implementation, the method of the present invention further includes after step S4: the central controller counts the number of times each STA identification information appears in the second power carrier signal of each photovoltaic string, and determines the starting photovoltaic unit or the ending photovoltaic unit corresponding to each photovoltaic string based on the statistical results.

[0102] Specifically, according to the statistical results, if a certain identification information appears twice, the photovoltaic unit corresponding to the certain identification information is the starting photovoltaic unit or the ending photovoltaic unit. For the photovoltaic units located at the starting end or the ending end of the photovoltaic string, since they each have only one adjacent photovoltaic unit, the number of times the STA identification information of the starting end or the ending photovoltaic unit appears in the second power carrier signal sent within the same photovoltaic string will be one less than the STA identification information of other photovoltaic units within the string. By analyzing the number of times these identification information appear, we can determine which STA identifications correspond to the photovoltaic units at the starting end or the ending end.

[0103] Taking the photovoltaic strings A1-A5 in Table 1 as an example, by counting the number of occurrences of the STA identification information in the second power carrier signal sent by each photovoltaic unit, we obtain: a1 appears 2 times, a2 appears 3 times, a3 appears 5 times, a4 appears 3 times, and a5 appears 2 times. Based on this information, it can be inferred that a1 and a5 correspond to the photovoltaic units at the starting end or the ending end of the photovoltaic string, respectively.

[0104] A photovoltaic string is composed of multiple photovoltaic units connected in series. The photovoltaic units in the same photovoltaic string share equal current, while the voltage is accumulated along the direction of the string. By determining the photovoltaic units at the starting and ending ends, we can more accurately evaluate the power stability and voltage range of the entire photovoltaic string, which is crucial for monitoring the performance of the entire photovoltaic string. For example, if the performance data of the photovoltaic unit at the starting or ending end is abnormal, this may indicate that there is a potential problem with the entire photovoltaic string and further inspection and maintenance are required. By analyzing the performance data of the photovoltaic units at the starting or ending end, we can understand the performance of the photovoltaic units at different positions of the string under conditions such as light and temperature, so as to optimize the string design and improve the string power generation efficiency.

[0105] As an optional specific implementation, after step S4, it also includes: the central controller generates a unique string identification code (String ID) for each determined photovoltaic string, and sends the string identification code to the corresponding photovoltaic unit; each photovoltaic unit stores the corresponding string identification code for communication between photovoltaic units or between photovoltaic units and the central controller. The photovoltaic unit in the embodiment of the present application stores the corresponding string identification code, so that the central controller can communicate more quickly during the communication process with the photovoltaic unit, avoiding delays caused by reading data. For example, the photovoltaic unit needs to disconnect the corresponding photovoltaic string due to an abnormality. At this time, the central controller can directly perform a fast shutdown operation of the photovoltaic string according to the string identification code contained in the abnormal information sent by the photovoltaic unit; and if the photovoltaic unit does not store the string identification code, the central controller needs to read the relevant data in the memory (for example, the corresponding table of identification information and string identification code) according to the identification information of the photovoltaic unit after receiving the information and determine the corresponding string identification code before the next related operation can be processed. Reading the data will cause a certain delay, thereby affecting the processing speed. It should be noted that the string identification code is the coding information used to uniquely identify the photovoltaic string. Each PV string is assigned a unique string identification code, which is used to distinguish different PV strings in the system. All PV cells in the same PV string share the same string identification code, while PV cells in different PV strings have different string identification codes. This design facilitates the central controller to manage and monitor the PV cells efficiently and orderly.

[0106] For example, in a photovoltaic system, suppose there are two photovoltaic strings, namely photovoltaic string A (including photovoltaic units A1, A2, A3, A4, A5) and photovoltaic string B (including photovoltaic units B1, B2, B3, B4, B5). In order to distinguish the two strings, the system will send the same string identification code Code1 to all photovoltaic units (A1, A2, A3, A4, A5) of photovoltaic string A, and send another different string identification code Code2 to all photovoltaic units (B1, B2, B3, B4, B5) of photovoltaic string B. In this way, the central controller can quickly and accurately identify the string to which each photovoltaic unit belongs based on the received string identification code, and then perform more refined management and monitoring of the photovoltaic system. Embodiment 3

[0107] An embodiment of the present invention further provides an electronic device, which includes a processor, a memory and a bus system, wherein the processor and the memory are connected via the bus system, the memory is used to store instructions, and the processor is used to execute the instructions stored in the memory to implement the above-mentioned photovoltaic string identification method. Embodiment 4

[0108] The embodiment of the present invention further provides a computer storage medium, which stores a computer software product. The computer software product includes several instructions for enabling a computer device to execute the above-mentioned photovoltaic string identification method.

[0109] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0110] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0111] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide for implementing the process in the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0112] It should be noted that the photovoltaic system embodiment, photovoltaic string identification method embodiment, electronic device embodiment and computer storage medium embodiment provided in the embodiments of the present application belong to the same concept; the technical features in the technical solutions recorded in each embodiment can be arbitrarily combined without conflict.

[0113] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from them are still within the protection scope of the invention.

Claims

1. A photovoltaic system, characterized in that: It includes multiple photovoltaic strings, inverters, and a central controller. The photovoltaic strings are connected to the inverter and the central controller respectively. The inverter is used to convert the direct current output by the photovoltaic strings into alternating current and output it. The central controller is used to monitor and adjust the photovoltaic strings. Each photovoltaic string includes at least three photovoltaic units. Each photovoltaic unit includes an STA and one or more photovoltaic modules connected to the STA. The photovoltaic modules are used to convert the radiation energy of sunlight into direct current. The STA of each photovoltaic unit is used to receive the first power carrier signal of the same signal strength sent by the STA of other photovoltaic units, and compare the received signal strengths to obtain the first STA identification information with the strongest signal strength and its corresponding first signal strength value, as well as the second STA identification information with the second strongest signal strength and its corresponding second signal strength value; wherein the first power carrier signal includes the identification information of the STA that sends the first power carrier signal, the first STA identification information refers to the identification information of the STA corresponding to the strongest signal strength in the received signal, and the second STA identification information refers to the identification information of the STA corresponding to the second strongest signal strength in the received signal; The STA of each photovoltaic unit is also used to send a second power carrier signal to the central controller; wherein the second power carrier signal includes the identification information of the STA sending the second power carrier signal, and the first STA identification information and the second STA identification information obtained by the STA; The central controller is specifically used for: If the second power carrier signal sent by the STA of a certain photovoltaic unit and the second power carrier signal sent by the STA of another photovoltaic unit have at least two identical identification information, the corresponding two photovoltaic units are the same photovoltaic string.

2. The photovoltaic system according to claim 1, characterized in that: The central controller is further used to count the number of times each identification information appears in the second power carrier signal of each photovoltaic string, and determine the starting photovoltaic unit or the ending photovoltaic unit corresponding to each photovoltaic string according to the statistical result.

3. The photovoltaic system according to claim 2, characterized in that: The central controller is used to determine the starting photovoltaic unit or the ending photovoltaic unit corresponding to each photovoltaic string according to the statistical results, specifically for: According to the statistical results, if a certain identification information appears twice, the photovoltaic unit corresponding to the certain identification information is a starting end photovoltaic unit or an ending end photovoltaic unit.

4. A photovoltaic string identification method, characterized in that: The method is applied to a photovoltaic system, which includes a plurality of photovoltaic strings, an inverter, and a central controller; the photovoltaic strings are connected to the inverter and the central controller respectively, the inverter is used to convert the direct current output by the photovoltaic strings into alternating current and output it, and the central controller is used to monitor and adjust the photovoltaic strings; each photovoltaic string includes at least three photovoltaic units, and the photovoltaic units include an STA and one or more photovoltaic modules connected to the STA, and the photovoltaic modules are used to convert solar energy into direct current; the method includes: The STA of each photovoltaic unit sends a first power carrier signal with the same signal strength; wherein the first power carrier signal includes identification information of the STA sending the first power carrier signal; The STA of each photovoltaic unit receives the first power carrier signal sent by the STA of other photovoltaic units, and compares the received signal strengths to obtain the first STA identification information with the strongest signal strength and its corresponding first signal strength value, as well as the second STA identification information with the second strongest signal strength and its corresponding second signal strength value; wherein the first STA identification information refers to the identification information of the STA corresponding to the strongest signal strength in the received signal, and the second STA identification information refers to the identification information of the STA corresponding to the second strongest signal strength in the received signal; The STA of each photovoltaic unit sends a second power carrier signal to the central controller; wherein the second power carrier signal includes the identification information of the STA sending the second power carrier signal, and the first STA identification information and the second STA identification information obtained by the STA; The central controller receives the second power carrier signal sent by the STA of each photovoltaic unit, and determines the photovoltaic string to which each photovoltaic unit belongs according to the identification information therein; The step of determining the photovoltaic string to which each photovoltaic unit belongs according to the identification information includes: If the second power carrier signal sent by the STA of a certain photovoltaic unit and the second power carrier signal sent by the STA of another photovoltaic unit have at least two identical identification information, the corresponding two photovoltaic units are the same photovoltaic string.

5. The photovoltaic string identification method according to claim 4, characterized in that: The method further comprises: The central controller counts the number of occurrences of each identification information in the second power carrier signal of each photovoltaic string, and determines the starting photovoltaic unit or the ending photovoltaic unit corresponding to each photovoltaic string according to the statistical result.

6. The photovoltaic string identification method according to claim 4, characterized in that: Determining the starting photovoltaic unit or the ending photovoltaic unit corresponding to each photovoltaic string according to the statistical results specifically includes: According to the statistical results, if a certain identification information appears twice, the photovoltaic unit corresponding to the certain identification information is a starting end photovoltaic unit or an ending end photovoltaic unit.

7. An electronic device, characterized in that: The electronic device includes a processor, a memory and a bus system, the processor and the memory are connected through the bus system, the memory is used to store instructions, and the processor is used to execute the instructions stored in the memory to implement the photovoltaic string identification method according to any one of claims 4 to 6.

8. A computer storage medium, characterized in that: The computer storage medium stores a computer software product, and the computer software product includes a number of instructions for enabling a computer device to execute the photovoltaic string identification method according to any one of claims 4 to 6.

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