Photovoltaic system and communication method

Abstract

The application discloses a photovoltaic system and a communication method, comprising: a plurality of optimizers and at least two inverters: a first inverter and a second inverter; the input end of the first inverter is connected with a plurality of optimizers connected in series, and the input end of the second inverter is connected with a plurality of optimizers connected in series; the input end of each optimizer is connected with a photovoltaic module; the first inverter and the second inverter are neighbors; the first inverter reads a neighbor network table from the second inverter, and selects an optimal frequency band as a working frequency band according to the neighbor network table; the neighbor network table comprises a current working frequency band of a neighbor inverter; the first inverter judges whether the working frequency band conflicts with the working frequency band of the second inverter, if the working frequency band conflicts with the working frequency band of the second inverter, the first inverter and the second inverter compete for the working frequency band according to a priority, and the party failing in the competition re-reads the neighbor network table and re-selects the working frequency band. The scheme solves the problem of communication signal coupling, and the instruction issued by the inverter can reach the corresponding optimizer.

Description

Technical Field

[0001] This application relates to the field of photovoltaic technology, specifically to a photovoltaic system and communication method. Background Technology

[0002] A photovoltaic system generally includes photovoltaic modules, optimizers, and inverters. The input of the optimizer is used to connect to the corresponding photovoltaic module, and the outputs of multiple optimizers are connected in series to the input of the inverter.

[0003] A typical photovoltaic system or power station includes many inverters. Installing all inverters together or placing all power lines in the same trench or cable tray can easily lead to communication signal coupling problems due to the close proximity of the inverters or power lines and the fact that the photovoltaic system uses PLC for communication, which is a high-frequency carrier communication.

[0004] For example, in actual operation, the inverter needs to send commands to the optimizer at its input end, but due to communication signal coupling problems, the commands may be sent to optimizers connected to other inverters, making it impossible to set the parameters of the corresponding optimizer, and may even cause the entire power plant to fail. Summary of the Invention

[0005] In view of this, this application provides a photovoltaic system and communication method that can solve the problem of communication signal coupling, thereby preventing the instructions issued by the inverter from failing to reach the corresponding optimizer.

[0006] This application provides a photovoltaic system, including: a plurality of optimizers and at least two inverters; the at least two inverters include: a first inverter and a second inverter;

[0007] The input of the first inverter is connected to multiple optimizers connected in series, and the input of the second inverter is also connected to multiple optimizers connected in series; the input of each optimizer is used to connect to the corresponding photovoltaic module.

[0008] The first inverter and the second inverter are neighbors;

[0009] The first inverter is used to read the neighbor network table from the second inverter and select the optimal frequency band as the operating frequency band according to the neighbor network table; the neighbor network table includes the current operating frequency bands of the neighbor inverters.

[0010] The first inverter determines whether its operating frequency band conflicts with that of the second inverter. If there is a conflict, the first and second inverters compete for the operating frequency band according to their priority. The one that loses the competition rereads the neighbor network table and selects a new operating frequency band.

[0011] Preferably, the first inverter and the second inverter compete for the operating frequency band according to priority, specifically including:

[0012] Priority is determined by the size of the beacon sequence number, the number of optimizers connected to the inverter, and the size of the power line carrier communication PLC communication identifier; the larger the beacon sequence number, the better the priority; the larger the number of optimizers, the higher the priority; and the larger the power line carrier communication PLC communication identifier, the higher the priority.

[0013] The inverter with higher priority successfully competes for the operating frequency band.

[0014] Preferably, the first inverter and the second inverter determine their priority based on the beacon sequence number, the number of optimizers connected to the inverters, and the size of the power line carrier communication PLC communication identifier, specifically including:

[0015] If at least one of the following is greater than that of the second inverter: the size of the beacon sequence number of the first inverter, the size of the number of optimizers connected to the inverter, and the size of the power line carrier communication PLC communication identifier, then the priority of the first inverter is determined to be higher than that of the second inverter.

[0016] Preferably, each inverter includes a power line communication PLC master node; the multiple optimizers connected in series at the input of each inverter include a power line communication PLC slave node;

[0017] The PLC master node and PLC slave node communicate via the operating frequency band.

[0018] Preferably, each inverter includes a component-level power electronic MLPE master controller;

[0019] The MLPE master controller is used to communicate with the WiNet module via the inverter's ARM.

[0020] The MLPE master controller is also used to communicate with the PLC master node;

[0021] The MLPE controller is also used to communicate with the inverter's DSP via the inverter's ARM.

[0022] This application also provides a communication method for a photovoltaic system, the photovoltaic system including: multiple optimizers and at least two inverters; the at least two inverters include: a first inverter and a second inverter; the input terminal of the first inverter is connected to multiple optimizers connected in series, and the input terminal of the second inverter is connected to multiple optimizers connected in series; the input terminal of each optimizer is used to connect to a corresponding photovoltaic module;

[0023] The method includes:

[0024] Read the neighbor network table from the second inverter and select the optimal frequency band as the operating frequency band based on the neighbor network table; the neighbor network table includes the current operating frequency bands of the neighbor inverters.

[0025] The first inverter determines whether its operating frequency band conflicts with that of the second inverter. If there is a conflict, the first and second inverters compete for the operating frequency band according to their priority. The one that loses the competition rereads the neighbor network table and selects a new operating frequency band.

[0026] Preferably, the competition for operating frequency bands based on priority includes:

[0027] Priority is determined by the size of the beacon sequence number, the number of optimizers connected to the inverter, and the size of the power line carrier communication PLC communication identifier; the larger the beacon sequence number, the better the priority; the larger the number of optimizers, the higher the priority; and the larger the power line carrier communication PLC communication identifier, the higher the priority.

[0028] Inverters with higher priority successfully compete for the operating frequency band. Priority is determined based on the beacon sequence number, the number of optimizers connected to the inverter, and the size of the power line carrier communication PLC communication identifier. Specifically, this includes:

[0029] If at least one of the following is greater than that of the second inverter: the size of the beacon sequence number of the first inverter, the size of the number of optimizers connected to the inverter, and the size of the power line carrier communication PLC communication identifier, then the priority of the first inverter is determined to be higher than that of the second inverter.

[0030] Preferably, each inverter includes a power line communication PLC master node; the multiple optimizers connected in series at the input of each inverter include a power line communication PLC slave node;

[0031] The PLC master node and PLC slave node communicate via the operating frequency band.

[0032] Preferably, the first inverter selects the optimal frequency band as the operating frequency band, enters a preset trial operation period, and leaves the operating frequency band after determining that there is a conflict in the operating frequency band and the preset trial operation period has ended.

[0033] Preferably, each inverter includes a component-level power electronic MLPE master controller;

[0034] The MLPE master controller is used to communicate with the WiNet module via the inverter's ARM.

[0035] The MLPE master controller is also used to communicate with the PLC master node;

[0036] The MLPE controller is also used to communicate with the inverter's DSP via the inverter's ARM.

[0037] Therefore, this application has the following beneficial effects:

[0038] The photovoltaic system provided in this application includes at least two inverters, each with its input terminal connected to multiple optimizers connected in series. The first inverter selects its operating frequency band based on a neighbor network table. When the operating frequency band conflicts with that of other inverters, each inverter competes to select its operating frequency band. The inverter with higher priority uses the optimal operating frequency band as the communication band with the optimizer, while the inverter with lower priority selects another operating frequency band. Ultimately, the operating frequency bands of each inverter are different, thus ensuring that when each inverter communicates with its corresponding optimizer, the communication signal uses a different operating frequency band, preventing communication signal coupling issues and ensuring that each inverter can accurately send instructions to its corresponding optimizer. Attached Figure Description

[0039] Figure 1 An architectural diagram of a photovoltaic system provided in this application embodiment;

[0040] Figure 2 A schematic diagram of another photovoltaic system provided in the embodiments of this application;

[0041] Figure 3 A schematic diagram of yet another photovoltaic system provided in this application embodiment;

[0042] Figure 4 A flowchart illustrating a communication method for a photovoltaic system provided in an embodiment of this application. Detailed Implementation

[0043] To enable those skilled in the art to better understand the technical solutions provided in the embodiments of this application, the application scenarios will be described below in conjunction with the accompanying drawings.

[0044] See Figure 1 This figure is an architectural diagram of a photovoltaic system provided in an embodiment of this application.

[0045] For ease of explanation, let's start with an inverter as an example.

[0046] Inverter 100 includes inverter circuitry, Module Level Power Electronics (MLPE) controller, and ARM.

[0047] The input of the inverter circuit is connected to multiple optimizers connected in series, such as optimizer 10, optimizer 20, and so on up to optimizer N0. The input of each optimizer is connected to the corresponding photovoltaic module. The outputs of the multiple optimizers are connected in series at the input of the inverter circuit, which can increase the input voltage of the inverter.

[0048] However, a photovoltaic system includes multiple inverters, and the input of each inverter is connected to multiple optimizers. When the inverter sends a command to the optimizer, since the operating frequency bands are the same in the traditional system, there is coupling interference between the communication signals. This causes the inverter to send a command to the optimizer connected to other inverters instead of the optimizer connected to itself.

[0049] To solve the above technical problems, the photovoltaic system provided in this application embodiment has each inverter competing for the operating frequency band, and the operating frequency bands of each inverter are different. This ensures that when each inverter communicates with the corresponding optimizer, the operating frequency band used for the communication signal is different, so there will be no problem of communication signal coupling, and each inverter can accurately send instructions to the corresponding optimizer.

[0050] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the embodiments of this application will be further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0051] See Figure 2 This figure is a schematic diagram of another photovoltaic system provided in an embodiment of this application.

[0052] The photovoltaic system provided in this embodiment includes: multiple optimizers and at least two inverters; the at least two inverters include: a first inverter 100 and a second inverter 200;

[0053] For ease of description, let's take a photovoltaic system with two inverters as an example. "Two inverters" refers to any inverter in the photovoltaic system. For example, for the first inverter 100, the second inverter 200 represents any neighboring inverter of the first inverter 100. It should be understood that the first inverter 100 can have one or more neighboring inverters. However, when there are multiple neighboring inverters, the working principle of each neighboring inverter is the same as that of the second inverter. Therefore, we will use one neighboring inverter as an example for introduction.

[0054] The input terminal of the first inverter 100 is connected to multiple optimizers connected in series, such as optimizer 10, optimizer 20 up to optimizer N0; the input terminal of the second inverter 200 is connected to multiple optimizers connected in series, such as optimizer 11, optimizer 21 up to optimizer N1; the input terminal of each optimizer is used to connect to the corresponding photovoltaic module (not shown in the figure).

[0055] Inverter 100 and inverter 200 are neighbors. It should be understood that any given inverter may have multiple neighboring inverters; this example only uses one inverter as a neighbor.

[0056] The first inverter 100 reads the neighbor network table from the second inverter 200 and selects the optimal frequency band as the operating frequency band based on the neighbor network table. The neighbor network table includes the current operating frequency bands of neighboring inverters. Since the neighbor network table includes the operating frequency bands of neighboring inverters, operating frequency bands not included in the neighbor network table are idle frequency bands. Idle frequency bands can be selected first as the operating frequency band. Alternatively, the frequency band with the best communication performance can be selected as the operating frequency band.

[0057] The first inverter 100 determines whether its operating frequency band conflicts with that of the second inverter 200. If both inverters operate on the same frequency band, a conflict is considered to exist. If a conflict occurs, the first inverter 100 and the second inverter 200 compete for the operating frequency band according to their priorities. The inverter that loses the competition rereads its neighbor network table; for example, it might be either the first inverter or the second inverter that rereads its neighbor network table, and then selects a new operating frequency band. In other words, when operating frequency bands conflict, the inverter with lower priority must relinquish its operating frequency band and select another frequency band. This ensures that each inverter operates on a different frequency band.

[0058] It should be understood that each inverter in a photovoltaic system sends messages in real time. Therefore, each inverter can obtain the operating frequency band of other inverters through the neighbor network table. If the frequency bands are the same, there will be a conflict.

[0059] This application does not specifically limit the factors determining priority; it can be a single factor or a combination of multiple factors. For example, the number of optimizers connected to each inverter can be considered; the larger the number, the higher the priority. Other factors may also be included.

[0060] The photovoltaic system provided in this application includes at least two inverters. The input of each inverter is connected to multiple optimizers connected in series. The first inverter selects the operating frequency band according to the neighbor network table. When the operating frequency band conflicts with other inverters, each inverter selects the operating frequency band through competition. The inverter with higher priority uses the optimal operating frequency band as the frequency band for communication with the optimizer, while the inverter with lower priority selects other operating frequency bands. In the end, the operating frequency bands of each inverter are different. This ensures that when each inverter communicates with the corresponding optimizer, the operating frequency band used for communication signals is different, so there will be no communication signal coupling problem, and each inverter can accurately send instructions to the corresponding optimizer.

[0061] One possible implementation involves the first inverter 100 and the second inverter 200 competing for the operating frequency band based on priority, specifically including:

[0062] Priority is determined by the size of the beacon sequence number, the number of optimizers connected to the inverter, and the size of the power line carrier communication PLC communication identifier; the larger the beacon sequence number, the better the priority; the larger the number of optimizers, the higher the priority; and the larger the power line carrier communication PLC communication identifier, the higher the priority.

[0063] The inverter with higher priority successfully competes for the operating frequency band.

[0064] Among them, the Beacon serves as a signal to help users monitor server operating resources and perform data analysis.

[0065] The first inverter selects the optimal frequency band as the operating frequency band, enters a preset trial operation period, and leaves the operating frequency band after determining that the operating frequency band is conflicted and the preset trial operation period has ended.

[0066] The PLC communication identifier is a unique identifier for communication between the master PLC and the slave PLC. The master PLC is located on the inverter side, and the slave PLC is located on the optimizer side.

[0067] It should be understood that the PLC communication identifier is randomly generated. The Beacon frame sending period is greater than 0, for example, it can be set to 1 / 4 of the preset trial operation period. The purpose of setting the Beacon frame sending period is to periodically send Beacon frames for monitoring and data analysis of server operating resources.

[0068] Another possible implementation involves determining the priority of the first and second inverters based on the beacon sequence number, the number of optimizers connected to the inverters, and the size of the power line carrier communication PLC communication identifier. Specifically, this includes:

[0069] If at least one of the following is greater than that of the second inverter: the size of the beacon sequence number of the first inverter, the size of the number of optimizers connected to the inverter, and the size of the power line carrier communication PLC communication identifier, then the priority of the first inverter is determined to be higher than that of the second inverter. That is, if any one of the three factors of the first inverter is greater than that of the second inverter, then the first inverter is considered to have a higher priority.

[0070] For example, if the beacon sequence number of the first inverter is the same as that of the second inverter, and the power line carrier communication PLC communication identifier of the first inverter is the same as that of the second inverter, but the number of optimizers connected to the first inverter is greater than the number of optimizers connected to the second inverter, then the priority of the first inverter is higher than that of the second inverter.

[0071] The following is combined Figure 3 This section provides a detailed explanation of the working principle of photovoltaic systems.

[0072] See Figure 3 This figure is a schematic diagram of another photovoltaic system provided in an embodiment of this application.

[0073] For ease of description, the photovoltaic system provided in this embodiment will continue to be introduced using an inverter as an example.

[0074] Each inverter includes a power line communication PLC master node 40; multiple optimizers connected in series at the input of each inverter include a power line communication PLC slave node 30.

[0075] The PLC master node 40 and the PLC slave node 30 communicate using the operating frequency band obtained in the above embodiments.

[0076] Each inverter includes a component-level power electronics MLPE master controller 50;

[0077] MLPE main controller 50 is used to communicate with the WiNet module via the inverter's ARM;

[0078] The MLPE master controller 50 communicates with the slave PLC of the optimizer through the master node PLC.

[0079] The MLPE main controller 50 is also used to communicate with the inverter's DSP via the inverter's ARM.

[0080] The inverter's ARM and DSP can communicate via a custom Modbus protocol.

[0081] Based on the photovoltaic system described in the above embodiments, this application also provides a communication method for the photovoltaic system, which will be described in detail below with reference to the accompanying drawings.

[0082] See Figure 4 The figure is a flowchart of a communication method for a photovoltaic system provided in an embodiment of this application.

[0083] The communication method for a photovoltaic system provided in this application embodiment includes: a plurality of optimizers and at least two inverters; the at least two inverters include: a first inverter and a second inverter; the input terminal of the first inverter is connected to a plurality of optimizers connected in series, and the input terminal of the second inverter is connected to a plurality of optimizers connected in series; the input terminal of each optimizer is used to connect to a corresponding photovoltaic module;

[0084] The method includes:

[0085] S401: Read the neighbor network table from the second inverter and select the optimal frequency band as the operating frequency band according to the neighbor network table; the neighbor network table includes the current operating frequency bands of the neighbor inverters.

[0086] S402: The first inverter determines whether its operating frequency band conflicts with that of the second inverter. If there is a conflict, the first inverter and the second inverter compete for the operating frequency band according to their priority. The one that loses the competition reads the neighbor network table again and selects a new operating frequency band.

[0087] Competition for operating frequency bands is based on priority, specifically including:

[0088] Priority is determined by the size of the beacon sequence number, the number of optimizers connected to the inverter, and the size of the power line carrier communication PLC communication identifier; the larger the beacon sequence number, the better the priority; the larger the number of optimizers, the higher the priority; and the larger the power line carrier communication PLC communication identifier, the higher the priority.

[0089] Inverters with higher priority successfully compete for the operating frequency band. Priority is determined based on the beacon sequence number, the number of optimizers connected to the inverter, and the size of the power line carrier communication PLC communication identifier. Specifically, this includes:

[0090] If at least one of the following is greater than that of the second inverter: the size of the beacon sequence number of the first inverter, the size of the number of optimizers connected to the inverter, and the size of the power line carrier communication PLC communication identifier, then the priority of the first inverter is determined to be higher than that of the second inverter.

[0091] Each inverter includes a power line communication PLC master node; multiple optimizers connected in series at the input of each inverter include a power line communication PLC slave node;

[0092] The PLC master node and PLC slave node communicate via the operating frequency band.

[0093] The first inverter selects the optimal frequency band as the operating frequency band, enters the preset trial operation period, and leaves the operating frequency band after determining that there is a conflict in the operating frequency band and the preset trial operation period has ended.

[0094] Each inverter includes a component-level power electronics (MLPE) master controller;

[0095] The MLPE master controller is used to communicate with the WiNet module via the inverter's ARM.

[0096] The MLPE master controller is also used to communicate with the PLC master node;

[0097] The MLPE main controller is also used to communicate with the inverter's DSP via the inverter's ARM.

[0098] The communication method provided in this application involves each inverter competing to select its operating frequency band. Inverters with higher priority use the optimal operating frequency band as the communication band with the optimizer, while inverters with lower priority select other operating frequency bands. Ultimately, the operating frequency bands of each inverter are different. This ensures that when each inverter communicates with its corresponding optimizer, the operating frequency band used for the communication signal is different, thus avoiding communication signal coupling issues and ensuring that each inverter can accurately send instructions to the corresponding optimizer.

[0099] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems or apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple, and relevant parts can be referred to the method section.

[0100] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A photovoltaic system, characterized in that, include: Multiple optimizers and at least two inverters; The at least two inverters include: a first inverter and a second inverter; each inverter includes a power line communication PLC master node; multiple optimizers connected in series at the input of each inverter include a power line communication PLC slave node; the PLC master node and the PLC slave node communicate via an operating frequency band; The input terminal of the first inverter is connected to multiple optimizers connected in series, and the input terminal of the second inverter is also connected to multiple optimizers connected in series; the input terminal of each optimizer is used to connect to a corresponding photovoltaic module. The first inverter and the second inverter are neighbors. The first inverter is used to read the neighbor network table from the second inverter and select the optimal frequency band as the operating frequency band according to the neighbor network table; the neighbor network table includes the current operating frequency bands of the neighbor inverters; The first inverter determines whether the operating frequency band conflicts with the operating frequency band of the second inverter. If there is a conflict, the first inverter and the second inverter compete for the operating frequency band according to priority. The party that loses the competition rereads the neighbor network table and reselects the operating frequency band.

2. The photovoltaic system according to claim 1, characterized in that, The first inverter and the second inverter competing for the operating frequency band according to priority specifically includes: Priority is determined based on the Beacon sequence number, the number of optimizers connected to the inverter, and the power line carrier communication PLC communication identifier; the larger the Beacon sequence number, the higher the priority; the larger the number of optimizers, the higher the priority; and the larger the power line carrier communication PLC communication identifier, the higher the priority. The inverter with higher priority successfully competes for the operating frequency band.

3. The photovoltaic system according to claim 2, characterized in that, The first inverter and the second inverter are prioritized based on the beacon sequence number, the number of optimizers connected to the inverter, and the power line carrier communication PLC communication identifier. Specifically, this includes: If at least one of the following is greater than that of the second inverter: the size of the Beacon sequence number of the first inverter, the size of the number of optimizers connected to the inverter, and the size of the power line carrier communication PLC communication identifier, then the priority of the first inverter is determined to be higher than that of the second inverter.

4. The photovoltaic system according to claim 3, characterized in that, Each of the inverters includes a component-level power electronics (MLPE) master controller; The MLPE master controller is used to communicate with the WiNet module through the inverter's ARM; The MLPE master controller is also used to communicate with the PLC master node; The MLPE master controller is also used to communicate with the inverter's DSP through the inverter's ARM.

5. A communication method for a photovoltaic system, characterized in that, The photovoltaic system includes: multiple optimizers and at least two inverters; each inverter includes a power line communication (PLC) master node; the input of each inverter is connected to multiple optimizers connected in series, including a PLC slave node; the PLC master node and the PLC slave node communicate via an operating frequency band; the at least two inverters include: a first inverter and a second inverter; the input of the first inverter is connected to multiple optimizers connected in series, and the input of the second inverter is connected to multiple optimizers connected in series; the input of each optimizer is used to connect to a corresponding photovoltaic module; The method includes: Read the neighbor network table from the second inverter, and select the optimal frequency band as the operating frequency band according to the neighbor network table; the neighbor network table includes the current operating frequency bands of the neighbor inverters. The first inverter determines whether the operating frequency band conflicts with the operating frequency band of the second inverter. If there is a conflict, the first inverter and the second inverter compete for the operating frequency band according to priority. The party that loses the competition rereads the neighbor network table and reselects the operating frequency band.

6. The communication method according to claim 5, characterized in that, The process of competing for the operating frequency band based on priority specifically includes: Priority is determined based on the Beacon sequence number, the number of optimizers connected to the inverter, and the power line carrier communication PLC communication identifier; the larger the Beacon sequence number, the higher the priority; the larger the number of optimizers, the higher the priority; and the larger the power line carrier communication PLC communication identifier, the higher the priority. Inverters with higher priority successfully compete for the operating frequency band. Priority is determined based on the beacon sequence number, the number of optimizers connected to the inverter, and the size of the power line carrier communication PLC communication identifier. Specifically, this includes: If at least one of the following is greater than that of the second inverter: the size of the Beacon sequence number of the first inverter, the size of the number of optimizers connected to the inverter, and the size of the power line carrier communication PLC communication identifier, then the priority of the first inverter is determined to be higher than that of the second inverter.

7. The communication method according to claim 5 or 6, characterized in that, The first inverter selects the optimal frequency band as the operating frequency band, enters a preset trial operation period, and leaves the operating frequency band after determining that the operating frequency band is conflicted and the preset trial operation period has ended.

8. The communication method according to claim 5 or 6, characterized in that, Each of the inverters includes a component-level power electronics (MLPE) master controller; The MLPE master controller is used to communicate with the WiNet module through the inverter's ARM; The MLPE master controller is also used to communicate with the PLC master node; The MLPE master controller is also used to communicate with the inverter's DSP through the inverter's ARM.

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