Flexible direct current submodule networking topology based on instruction shortest path

Abstract

The invention relates to a flexible direct-current sub-module networking topology based on an instruction shortest path, and belongs to the field of flexible direct-current power transmission of a power system. In combination with the number of power modules, a communication network topology model which is in a cube shape as far as possible is constructed according to a networking topology design rule, and a starting point sub-module on each edge of the topology model is selected. The shortest path from each module in the topology to the starting point sub-module is selected based on the shortest path algorithm so as to obtain the shortest path to the valve control device, the physical length of the path is considered, and various factors such as the path reliability and the bandwidth utilization rate are comprehensively considered, so that the optimal communication path can be calculated, and the communication efficiency is improved. And the data transmission efficiency and reliability are improved. According to the technical scheme, the complex communication network topology structure can be visually presented, operation and maintenance personnel can know the specific situation of each communication path, the operation and maintenance personnel can better understand and monitor the operation state of the whole system, and powerful support is provided for follow-up troubleshooting and performance adjustment and optimization.

Description

Technical Field

[0001] This invention relates to a flexible DC submodule networking topology based on the shortest path of instructions, belonging to the field of flexible DC transmission in power systems. Background Technology

[0002] In existing flexible DC valve control equipment, the main control chassis is the core control unit of the entire system. It is responsible for receiving various instructions, parameter settings, and monitoring requirements from external or internal sources, and for performing overall scheduling and management of the power system based on this information. The main control chassis sends control signals to the sub-modules in the flexible DC valve control equipment. These signals include, but are not limited to, switch control, controlling the opening and closing of sub-modules, operating mode switching, and adjusting the operating mode of sub-modules according to system requirements, such as constant voltage, constant current, and constant power; protection commands; and sending protection commands to sub-modules when abnormalities (such as over-temperature, over-voltage, and over-current) are detected, so that the sub-modules enter a safe state.

[0003] The commands issued by the valve control device are encoded and sent to each submodule. After successful verification, the submodule extracts the command subdata related to itself based on its own identification information and executes the corresponding operation. After executing the command, the submodule generates corresponding status data and sends it to the valve control system. This status data is used to characterize the actual working status and performance parameters of the submodule.

[0004] As can be seen from the above, communication between valve control equipment and sub-modules is crucial during the operation of power systems. A fast and complete overall communication link is one of the key requirements for valve control equipment. The integrity and length of the communication link between the main control chassis and the sub-modules affect the control effect and efficiency of the valve control equipment on the sub-modules.

[0005] In the current field of flexible DC valve control equipment, the number of submodules in different power systems typically varies. There is insufficient research on designing a network topology with the shortest communication path, particularly regarding the complex communication links between the control cabinet and submodules. This is mainly reflected in the inability to clearly define specific communication paths and the inability to effectively evaluate and optimize the performance of these paths. This problem not only affects the reliability and efficiency of data transmission but also increases the complexity of system fault diagnosis and maintenance. Summary of the Invention

[0006] The purpose of this invention is to provide a flexible linear submodule networking topology based on the shortest command path, in order to solve the problems of unclear definition of complex communication link paths between control chassis and submodules in valve control equipment, the inability to effectively evaluate and optimize the performance of communication link paths, which leads to a decrease in the reliability and efficiency of data transmission, and increases the complexity of system fault diagnosis and maintenance.

[0007] To achieve the above objectives, the present invention includes:

[0008] The flexible linear submodule networking topology based on the shortest instruction path of the present invention includes multiple submodules as communication nodes in the network. Each communication node is arranged in a two-dimensional array and each communication node is connected to the communication nodes in its four neighboring domains.

[0009] The rows and columns of the two-dimensional array are determined with the goal of minimizing the product of the rows and columns of the two-dimensional array, and the product is greater than or equal to the total number of sub-modules and the absolute value of the difference between the rows and columns is less than or equal to 1.

[0010] The first and last rows, and the first and last columns of the two-dimensional array each have at least one sub-module for direct communication with the valve control. The sub-module for direct communication with the valve control is called the starting sub-module.

[0011] For non-starting submodules, the shortest path in the communication path to each starting submodule is calculated as the final path. The non-starting submodules use this final path to interact with the valve control.

[0012] Furthermore, each of the first and last rows, and the first and last columns of the two-dimensional array has only one starting sub-module, which is located at the very center or near the center of the first and last rows and the first and last columns, respectively.

[0013] Furthermore, the final path is calculated as follows: first, the shortest path among the communication paths from a non-starting submodule to a starting submodule is calculated as the control path; then, the shortest path among the communication paths from a starting submodule to another starting submodule is also calculated as the control path, thus obtaining the same number of control paths as the number of starting submodules; then, the shortest path is selected from all control paths as the final path.

[0014] Furthermore, the shortest path is selected from all control paths based on the transmission rate and length of the lines between submodules.

[0015] Furthermore, Dijkstra, Floyd, Floyd-Warshall, or Bellman-Ford algorithms are used to calculate the shortest path in the communication path from a non-starting submodule to a starting submodule.

[0016] Furthermore, when the number of submodules in the first row, last row, first column, or last column is odd, the starting submodule is the submodule in the middle of that row or column; when the number of submodules in the first row, last row, first column, or last column is even, the starting submodule is either one of the two submodules in the middle of that row or column.

[0017] The beneficial effects of this invention are as follows:

[0018] The present invention discloses a flexible linear submodule network topology based on the shortest path of instructions, comprising multiple submodules as communication nodes in the network. These communication nodes are arranged in a two-dimensional array, with each node communicating with its four neighboring nodes. The goal is to minimize the communication path of each node, and each node has multiple paths connecting to other communication nodes. The rows and columns of the two-dimensional array are determined by minimizing the product of the rows and columns, and the product must be greater than or equal to the total number of submodules, and the absolute value of the difference between the rows and columns must be less than or equal to 1. This arrangement of the submodules in the two-dimensional array is maximized to form a "U" shape (square), laying the topological foundation for finding the shortest path. At least one submodule is located in the first and last rows, and in the first and last columns of the two-dimensional array, for communication with valves. The system establishes a direct communication connection with the valve control unit. The submodule used for this direct communication connection is the starting submodule. For non-starting submodules, the shortest path from the communication path to each starting submodule is calculated as the final path. These non-starting submodules use this final path to interact with the valve control unit. By constructing a flexible direct communication submodule topology, each submodule has four alternative shortest paths to communicate with the valve control unit via optical fiber. The shortest path is then selected as the communication path between the submodule and the valve control unit. Essentially, the starting submodule acts as a cluster center to group the non-starting submodules. Non-starting submodules closer to the starting submodule are grouped together, allowing them to communicate with the valve group via the grouped starting submodules. This significantly shortens communication time, simplifies fiber optic maintenance, and reduces operating costs. Attached Figure Description

[0019] Figure 1 This is a flowchart of the shortest path determination method of the present invention applicable to the shortest path of flexible submodule networking topology based on instruction;

[0020] Figure 2 This is a schematic diagram of the network topology design rules for the flexible straight submodule network topology based on the shortest instruction path of the present invention;

[0021] Figure 3 This is a schematic diagram of the shortest path obtained by the flexible straight submodule networking topology calculation based on the shortest path of instructions according to the present invention;

[0022] Figure 4 This is a schematic diagram of the shortest path in the flexible straight submodule network topology of the present invention when there is a faulty submodule;

[0023] Figure 5 This is a schematic diagram of a flexible linear submodule network topology composed of 24 submodules based on the shortest path of instructions. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings.

[0025] The concept of this invention is to assemble multiple sub-modules, which serve as communication nodes in a network, into a flexible linear sub-module topology according to the following rules: Each communication node is arranged in a two-dimensional array, and each communication node is connected to its four neighboring communication nodes; the rows and columns of the two-dimensional array are determined with the objective of minimizing the product of the rows and columns, and the product must be greater than or equal to the total number of sub-modules, and the absolute value of the difference between the rows and columns must be less than or equal to 1; at least one sub-module is located in the first and last rows, and in the first and last columns of the two-dimensional array for direct communication with the valve control device, and this sub-module for direct communication with the valve control device is called the starting sub-module; for non-starting sub-modules, the shortest path among the communication paths to each starting sub-module is calculated as the final path, and the non-starting sub-module uses this final path to interact with the valve control device. By constructing a flexible linear sub-module topology, each sub-module has four alternative shortest paths to communicate with the valve control device via optical fiber, shortening communication time and saving operating costs.

[0026] An implementation method for a flexible linear submodule networking topology based on the shortest command path:

[0027] like Figure 1 As shown, the design of the flexible linear submodule network topology based on the shortest path of instructions and the determination of the shortest path in the topology are performed:

[0028] (1) Design the network topology of the flexible linear submodule based on the shortest path of instructions according to the following rules:

[0029] The communication nodes in the network are arranged in a two-dimensional array, and each communication node is connected to the communication nodes in its four neighboring domains. The number of rows and columns of the two-dimensional array is determined with the goal of minimizing the product of the number of rows and columns of the two-dimensional array, and the product is greater than or equal to the total number of communication nodes, and the absolute value of the difference between the number of rows and columns is less than or equal to 1, so that the two-dimensional array composed of communication nodes is arranged in a "U" shape (square) to the greatest extent.

[0030] The first and last rows, and the first and last columns of the two-dimensional array each have at least one communication node for direct communication with the valve control. The communication node used for direct communication with the valve control is called the starting communication node.

[0031] For non-starting communication nodes, the shortest path among the communication paths to each starting communication node is calculated as the final path. The non-starting communication nodes use this final path to interact with the valve control.

[0032] The design rules of the flexible straight submodule network topology based on the shortest instruction path in this embodiment are explained by taking a submodule as a specific example of a communication node.

[0033] Let N be the number of submodules. When N is not a square number, construct a flexible linear submodule network topology based on the shortest instruction path. In a two-dimensional array, if the remaining sub-modules cannot form a complete edge of the two-dimensional array: First, arrange them one by one along the y-axis in the last column of the topology, and finally form... A two-dimensional array; if The two-dimensional array is first arranged sequentially along the x-axis in the last row of the two-dimensional array, ultimately forming... A two-dimensional array.

[0034] Edge selection of a two-dimensional array composed of an odd number of sub-modules An even number of submodules form the starting power block, and the edge composed of an even number of submodules is selected as the first... or the Each submodule serves as the starting submodule of the corresponding edge (that is, the two middle submodules of each even-numbered submodule edge).

[0035] When N is a square number, constructing the submodule Two-dimensional array. When N is a square number and When the number is odd, the first edge of each of the four edges of the two-dimensional array is... Each submodule serves as the starting module for each edge, connecting to the valve control command fiber; when N is a perfect square and When the number is even, the first edge of each of the four sides of the two-dimensional array is... or the Each submodule (that is, the two middle submodules of each even-numbered submodule edge) serves as the starting submodule for each edge.

[0036] In other words, the starting sub-modules of the two-dimensional array are located at the middle or near the middle of the first and last rows, and the first and last columns of the two-dimensional array, respectively.

[0037] As an improved implementation, when determining the starting submodule for each even-numbered edge in the topology, the submodule with the smaller index is selected as the starting submodule.

[0038] In the two-dimensional array, the starting submodule of each edge is connected to the corresponding valve control command fiber. This rule can expand the submodule connection to the maximum extent in a "U" shape, which makes it easy to calculate the shortest path of the flexible straight submodule network topology connected to the valve control command fiber based on the shortest path of the command.

[0039] like Figure 2As shown, assume there are a total of n*m (m≥n) power modules, and the external valve-controlled optical fiber is connected to the starting sub-module of each side of the network topology.

[0040] N=24 is used as an example to illustrate the network topology design rules in this step:

[0041] 24 sub-modules form a 4*5 two-dimensional array. Since 24 > 4*5 = 20, the 24 sub-modules are divided into 4*5 + 4 sub-modules. The remaining 4 modules are placed in the row below the 4th row of the two-dimensional array to form the 5th row. The sub-module at the middle of each edge is taken as the starting sub-module and connected to the corresponding optical fiber, as shown below. Figure 5 As shown.

[0042] (2) Design the actual network topology of the sub-modules according to the network topology design rules, and arrange the communication status of each sub-module in a fixed manner according to the topology design valve control sending command communication protocol.

[0043] (3) Construct a weighted directed graph based on the network topology, taking the starting submodule of each edge in the two-dimensional array as the starting point and each non-starting submodule as the ending point, and using the communication status bits as weights. The weight for normal communication status is set to 1, and the weight for abnormal communication status is set to positive infinity.

[0044] (4) Use shortest path algorithms, including but not limited to Dijkstra, Floyd, Floyd-Warshall, Bellman-Ford, etc., to calculate the shortest path from each starting point to each ending point (1 to n); each non-starting point submodule has multiple paths to the starting point submodule. Compare the lengths of each path, and the shortest path from the starting point submodule to the corresponding non-starting point submodule for the valve control command is called the control path.

[0045] The control path from the starting submodule to each submodule plus the fiber optic length from the corresponding starting submodule to the valve control device is the shortest path from the valve control device to each submodule, which is called the final path.

[0046] In the two-dimensional array, the starting sub-modules corresponding to the four edges are all connected to the valve control device via optical fibers. The length difference between the four optical fibers can be ignored. The process of finding the final path from the valve control device to each sub-module in the two-dimensional array can be regarded as finding the control path among the paths from the sub-modules in the two-dimensional array to the four starting sub-modules.

[0047] When the control path length and the fiber length are almost the same, the path with the fastest transmission rate is selected as the final path based on the transmission rate of each fiber.

[0048] Configure communication protocols with the backend and send the shortest path to the backend for display according to the protocols; if the port communication status changes, recalculate the shortest path and send a communication abnormality alarm.

[0049] Taking a submodule number N of 25 as a specific implementation method, the shortest path determination method of the present invention applicable to flexible straight submodule fiber optic networking is described in detail below:

[0050] Design the network topology for a submodule with N=25 using network topology design rules:

[0051] like Figure 1 As shown, the number of submodules N is 25. A 5*5 two-dimensional array is formed according to a method for constructing a two-dimensional array of submodules in a flexible straight submodule networking topology implementation based on the shortest instruction path. The sequence number of each submodule is determined in order from top to bottom and from left to right.

[0052] The Floyd algorithm is used as a specific implementation of the shortest path algorithm to calculate the shortest path in a 5*5 two-dimensional array. Specifically, the shortest path from the starting sub-modules 3, 11, 15, and 23 in the two-dimensional array to each sub-module (sub-module 1 to sub-module 25) is calculated. The shortest path calculation results are as follows:

[0053] For the starting submodule 3, calculate the shortest path to each submodule and store it in the dist array:

[0054] path[2,3,-1,3,4,1,2,3,8,9,6,7,8,13,14,11,12,13,18,19,16,17,18,23,24];

[0055] dist[2,1,0,1,2,3,2,1,2,3,4,3,2,3,4,5,4,3,4,5,6,5,4,5,6];

[0056] For starting point 11:

[0057] path[6,1,2,3,4,11,6,7,8,9,-1,11,12,13,14,11,12,13,14,15,16,17,18,19,20,];

[0058] dist[2,3,4,5,6,1,2,3,4,5,0,1,2,3,4,5,2,3,4,5,2,3,4,5,6,];

[0059] For starting point 15:

[0060] path[2,3,4,5,10,7,8,9,10,15,12,13,14,15,-1,16,17,19,20,15,22,23,14,25,20,];

[0061] dist[6,5,4,3,2,5,4,3,2,1,4,3,2,1,0,5,4,3,2,1,6,5,4,3,2,];

[0062] Regarding starting point 23:

[0063] path[1,3,8,3,4,7,8,13,8,9,12,13,18,13,14,17,18,23,18,19,22,23,-1,23,24,];

[0064] dist[6,5,4,5,6,5,4,3,4,5,4,3,2,3,4,3,2,1,2,3,2,1,0,1,2,];

[0065] Taking the starting submodule 3 as an example, the path array stores the index of the previous submodule on the path from other submodules to the starting submodule 3. For example, path[0] = 2 means that the previous submodule on the path from module 1 (the array index starts from 0, and path[0] stores the value related to the first submodule) to the starting submodule 3 is submodule 2. path[1] = 3 means that the previous submodule on the path from submodule 2 to the starting submodule 3 is 3. We can get that the path from submodule 1 to the starting submodule 3 is 1 -> 2 -> 3, and the path length is 2; the path from submodule 2 to the starting submodule 3 is 2 -> 3, and the path length is 1. The dist array stores the shortest path length from each submodule to the starting submodule 3 calculated from the path array. From the simple calculation of the path array above, we can get that in the dist array: dist[0] = 2, dist[1] = 1. The calculation of the shortest path from other submodules to the starting submodule is calculated according to the corresponding path array, which will not be elaborated further.

[0066] Each submodule has a `dist` array connecting it to one of the four starting submodules (module 3, module 11, module 15, and module 23). Each array stores the length of the shortest path from each submodule in the two-dimensional array to that starting submodule. The final shortest path is selected by comparing the lengths of all the shortest paths from each submodule; this is the shortest path to be displayed in the backend. This shortest path is then uploaded to the backend. Figure 3 As shown, the submodules in the 5*5 two-dimensional array are divided into four parts, corresponding to the submodules with the shortest path from the starting submodules (numbered 5, 11, 15, and 23). Since the length difference of the four optical fibers is minimal, the shortest distance from the submodule to the valve control device can be simplified to the shortest distance from the submodule to the starting submodule.

[0067] When a submodule has the same shortest path to two or more starting submodules, it is necessary to compare the transmission rates of the optical fibers between the corresponding starting submodule and the valve control device, and select the starting submodule corresponding to the optical fiber with the fastest transmission rate as the starting submodule corresponding to this submodule.

[0068] The green path needs to be prioritized based on the transmission rate and fiber length of the four actual control paths. The path array above is temporarily prioritized by the sequence number. That is, when the control paths are the same, the control path corresponding to the starting submodule with the smaller sequence number is selected.

[0069] The system also provides a method for displaying the shortest path in the background under fault conditions. Assuming submodule 12 fails, the shortest path in the topology is recalculated, but the paths to and from submodule 12 are no longer calculated. The resulting shortest path displayed in the background is as follows: Figure 4 As shown.

[0070] This invention provides a flexible submodule network topology based on the shortest path of instructions. Combining the number of power modules and following network topology design rules, a communication network topology model is constructed that is as cubic as possible, and the starting submodule on each edge of the topology model is selected. Based on the network topology model and the starting submodule, a shortest path algorithm is used to select the shortest path from each module in the topology to the starting submodule, thus deriving the shortest path from each submodule to the valve control device. This algorithm considers not only the physical length of the path but also various factors such as path reliability and bandwidth utilization, thereby calculating the optimal communication path. Through this process, this invention not only achieves path optimization for the entire link but also significantly improves the efficiency and reliability of data transmission. It also provides path visualization functionality. Complex communication network topologies can be presented in an intuitive and easy-to-understand graphical manner, allowing maintenance personnel to clearly understand the specific situation of each communication path. This not only helps maintenance personnel better understand and monitor the operating status of the entire system but also provides strong support for subsequent troubleshooting and performance tuning.

Claims

1. A flexible linear submodule network topology based on instruction shortest path, comprising multiple submodules acting as communication nodes in the network, characterized in that, Each communication node is arranged in a two-dimensional array, and each communication node is connected to the communication nodes in its four neighboring domains. The rows and columns of the two-dimensional array are determined with the goal of minimizing the product of the rows and columns of the two-dimensional array, and the product is greater than or equal to the total number of sub-modules and the absolute value of the difference between the rows and columns is less than or equal to 1. The first and last rows, and the first and last columns of the two-dimensional array each have at least one sub-module for direct communication with the valve control. The sub-module for direct communication with the valve control is called the starting sub-module. For non-starting submodules, the shortest path in the communication path to each starting submodule is calculated as the final path. The non-starting submodules use this final path to interact with the valve control.

2. The flexible linear submodule networking topology based on the shortest instruction path according to claim 1, characterized in that, The first and last rows, and the first and last columns of the two-dimensional array each have only one starting sub-module, which is located at the very center or near the center of the first and last rows and the first and last columns, respectively.

3. The flexible linear submodule networking topology based on the shortest instruction path according to claim 1, characterized in that, The final path is calculated as follows: First, the shortest path among the communication paths from a non-starting submodule to a starting submodule is calculated as the control path. Then, the shortest path among the communication paths from a starting submodule to another starting submodule is also calculated as the control path. This process yields the same number of control paths as the number of starting submodules. Finally, the shortest path is selected from all control paths as the final path.

4. The flexible linear submodule networking topology based on the shortest instruction path according to claim 3, characterized in that, The shortest path is selected from all control paths based on the transmission rate and length of the lines between submodules.

5. The flexible linear submodule networking topology based on the shortest instruction path according to claim 3, characterized in that, The shortest path in the communication path from a non-starting submodule to a starting submodule is calculated using Dijkstra, Floyd, Floyd-Warshall, or Bellman-Ford algorithms.

6. The flexible linear submodule networking topology based on the shortest instruction path according to claim 2, characterized in that, When the number of submodules in the first row, last row, first column, or last column is odd, the starting submodule is the submodule in the middle of that row or column; when the number of submodules in the first row, last row, first column, or last column is even, the starting submodule is either one of the two submodules in the middle of that row or column.

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