Physical channel modeling method, device and system for low-voltage power line carrier communication

Abstract

The invention discloses a low-voltage power line carrier communication physical channel modeling method, device and system, and belongs to the low-voltage power line carrier communication technology. According to the method, channel models of bus type, tree type and daisy chain type power line network topologies are respectively constructed based on a transmission line theory, a low-voltage power line carrier communication channel parameter measuring device is used, and wide channel attenuation testing is carried out aiming at the network topologies. And finally, correcting the channel model in combination with measured data, and deeply analyzing channel characteristics under different network topology structures through the model. According to the method, channel attenuation of different power line topology networks is actually measured and analyzed, so that channel models of different topology structures are corrected, and more accurate and practical wiring suggestions can be provided. According to the method, the communication efficiency can be improved, the stability and reliability of the system can be enhanced, and powerful support is provided for optimization design of the low-voltage power line communication system.

Description

Technical Field

[0001] The present invention relates to the technical field of low-voltage power line carrier communication, and in particular to a method, device and system for modeling a physical channel of a low-voltage power line carrier communication. Background Art

[0002] With the rapid expansion and construction of smart grids, the application of low-voltage power line carrier communication technology in smart homes, centralized meter reading, distribution automation and other fields is increasing. However, the power line system has problems such as poor impedance matching, unpredictable noise interference, significant signal attenuation and frequent changes in channel characteristics. In addition, the signal is easily affected by factors such as high-intensity noise, variable network structure and random access of a large number of node users during transmission, which not only affects the stability and reliability of the distribution system, but also poses challenges to the research of power line carrier communication technology. Therefore, constructing an accurate power line carrier communication channel transmission model, determining the optimal signal transmission frequency based on frequency selectivity, analyzing the communication network structure and proposing a better line layout plan are of great theoretical and practical significance for promoting the advancement of power line carrier communication technology and its practical application.

[0003] Currently, most of the research on power line channel models relies on simulation software or its results cannot be directly applied to actual low-voltage lines, making it difficult to effectively guide the specific design of low-voltage power line communication systems. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and to provide a method, device and system for modeling a physical channel of a low-voltage power line carrier communication, so as to solve the problem that most of the research on power line channel models in the prior art relies on simulation software or its results and cannot be directly applied to actual low-voltage lines. In order to achieve the above object, the present invention adopts the following technical solutions: A low voltage power line carrier communication channel modeling method comprises the following steps: S1, obtaining global parameters of the low voltage power grid; S2, inputting the global parameters into three power line topology network structures to obtain a predicted attenuation value of each power line topology network structure; the three power line topology network structures include a bus type network channel model, a tree type network channel model and a daisy chain type network channel model; The acquisition process of the three power line topology networks is as follows: based on the transmission line model, three power line topology networks are constructed for the experimental low-voltage power line network structure; the channel attenuation of the bus network channel model, the tree network channel model and the daisy chain network channel model are measured respectively; the three power line topology networks are corrected respectively in combination with the measured data to obtain the three power line topology networks; the correction items include the attenuation value of the system itself, the influence value of the trunk line in the topology network on the attenuation, and the influence value of the branch line on the attenuation; S3, determining a power line topology network structure corresponding to the low voltage power grid based on the attenuation value.

[0005] A further improvement of the present invention is: Preferably, in S1, the global parameters of the low-voltage power grid include power line distribution parameters and load organization; the power line distribution parameters include resistance, inductance, capacitance and conductance values ​​per unit length of a uniform power transmission line.

[0006] Preferably, in S2, during the construction of the power line topology network, channel noise and interference factors are ignored, and the impedance of each branch node is adjusted by using a method in which the branch lines are equivalent to parallel loads.

[0007] Preferably, in S2, the measurement result of the power line topology network is presented in the form of an amplitude-frequency response curve.

[0008] Preferably, in S2, the formula for correcting the three power line topology networks respectively in combination with the measured data is:

[0009] Among them, X is the simulated channel attenuation data, and Y is the channel attenuation data based on the actual measurement of the system. is the system's own attenuation value, and are the total length of the trunk and the total length of the branches of the tested topology network, and The trunk length weight coefficient and branch length weight coefficient are fitted by the multivariate linear regression model respectively.

[0010] Preferably, the system's own attenuation is a weakening of the signal strength caused by the devices and connecting lines within the system.

[0011] Preferably, the weights in the topology trunk weighted attenuation and the topology branch weighted attenuation are obtained through a multiple linear regression model, and the multiple linear regression model is obtained based on actual measurement data.

[0012] Preferably, in S3, the bus-type network channel model is applicable to a low-voltage power grid with multiple nodes, the tree-type network channel model is applicable to a low-voltage power grid with an equal number of nodes, and the daisy-chain-type network channel model is applicable to a low-voltage power grid with a long communication distance.

[0013] A low voltage power line carrier communication channel modeling device, comprising: A collection unit, used for acquiring global parameters of the low voltage power grid; A prediction unit, used for inputting global parameters into three power line topology network structures to obtain a predicted attenuation value of each power line topology network structure; the three power line topology network structures include a bus type network channel model, a tree type network channel model and a daisy chain type network channel model; The acquisition process of the three power line topology networks is as follows: based on the transmission line model, three power line topology networks are constructed for the experimental low-voltage power line network structure; the channel attenuation of the bus network channel model, the tree network channel model and the daisy chain network channel model are measured respectively; the three power line topology networks are corrected respectively in combination with the measured data to obtain the three power line topology networks; the correction items include the attenuation value of the system itself, the influence value of the trunk line in the topology network on the attenuation, and the influence value of the branch line on the attenuation; The confirmation unit is used to determine the power line topology network structure corresponding to the low-voltage power grid based on the attenuation value.

[0014] A low-voltage power line carrier communication channel modeling system for implementing the above-mentioned modeling method comprises a DC power supply, a spectrum analyzer, a signal acquisition board, a signal processor and a host computer; the DC power supply, the spectrum analyzer and the signal acquisition board are simultaneously connected to the power line topology network structure by electrical signals, the signal acquisition board is connected to the signal processor by electrical signals, and the signal processor is connected to the host computer by electrical signals.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The invention discloses a method for modeling a low-voltage power line carrier communication channel. Based on the transmission line theory, the method constructs channel models of three types of power line network topologies, namely bus type, tree type and daisy chain type, respectively, and uses a low-voltage power line carrier communication channel parameter measurement device to perform extensive channel attenuation tests on the above-mentioned types of network topologies. Finally, the channel model is corrected in combination with measured data, and the channel characteristics under different network topologies are deeply analyzed through the model. This method measures and analyzes the channel attenuation of different power line topology networks, thereby correcting the channel models of different topological structures, and can provide more accurate and practical wiring suggestions. This method can not only improve communication efficiency, but also enhance the stability and reliability of the system, and provide strong support for the optimization design of low-voltage power line communication systems. These conclusions provide valuable references for the design and optimization of different types of power line carrier communication networks. It solves the problem that most current research on power line channel models relies on simulation software or its results cannot be directly applied to actual low-voltage lines. This method can improve the accuracy of the model, ensure better reflection of the actual situation, and provide a scientific basis and technical support for the design and optimization of low-voltage power line carrier communication systems.

[0016] The present invention also discloses a complete and independently deployable low-voltage power line carrier communication system, which can not only adapt to rapid installation and operation in a variety of environments, but also has the ability to evaluate communication performance and measure channel attenuation. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of a method for correcting a low voltage power line carrier communication channel model; Figure 2 It is a schematic diagram of a bus-type power line topology network; Figure 3 This is a schematic diagram of a tree-type power line topology network; Figure 4 It is a schematic diagram of a daisy chain power line topology network; Figure 5 It is a structural diagram of a low voltage power line carrier communication system; Figure 6 This is a bus simulation result diagram of Example 2; Figure 7 This is a tree-type simulation result diagram of Example 2; Figure 8 This is a diagram of the daisy chain simulation results of Example 2. DETAILED DESCRIPTION

[0018] In the following, the terms "first", "second", "third", and "fourth" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first", "second", "third", and "fourth" may explicitly or implicitly include one or more of the features.

[0019] The co-shooting method provided in the embodiment of the present application can be applied to terminal devices such as mobile phones, tablet computers, wearable devices, vehicle-mounted devices, augmented reality (AR) / virtual reality (VR) devices, laptop computers, ultra-mobile personal computers (UMPC), netbooks, personal digital assistants (PDA), etc. The embodiment of the present application does not impose any restrictions on the specific type of the terminal device.

[0020] It should be noted that the terms "first", "second", etc. in the specification and drawings of the present invention are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0021] A first aspect of the present invention provides a low voltage power line carrier communication channel modeling method, comprising the following steps: S1, obtaining global parameters of the low voltage power grid; S2, inputting the global parameters into three power line topology network structures to obtain a predicted attenuation value of each power line topology network structure; the three power line topology network structures include a bus type network channel model, a tree type network channel model and a daisy chain type network channel model; S3, determining a power line topology network structure corresponding to the low voltage power grid based on the attenuation value.

[0022] In some embodiments of the present invention, in S1, the global parameters of the low voltage power grid include: the global parameters include two parts: power line distribution parameters and load resistance. The power line distribution parameters mainly include resistance, inductance, capacitance and conductance values ​​per unit length of a uniform power transmission line.

[0023] After the global parameters, the parameters required by different types of topology networks are also different. The parameters required for bus topology include: number of nodes, trunk length, and branch length. The parameters required for tree topology include: number of nodes, trunk length, number of branches, and branch length. The parameters required for daisy chain topology include: number of links, link length, number of branches on the link, and branch length. The total communication distance of the daisy chain topology is the sum of all link lengths.

[0024] In S2, the three power line topology network structures are pre-built models. The specific construction process is as follows: S201, based on the transmission line theory, three power line network topology channel models are constructed, namely bus type, tree type and daisy chain type. The schematic diagrams of the bus type, tree type and daisy chain type network topology are shown in the figure below. Figure 2 , Figure 3 , Figure 4 shown.

[0025] S202, using a low voltage power line carrier communication channel parameter measurement device, a wide range of channel attenuation tests were conducted for each type of network topology mentioned above; S203, the channel model is calibrated in combination with the measured data, and the channel characteristics under different network topologies are deeply analyzed through the model. This series of steps is aimed at improving the accuracy of the model and ensuring that it can better reflect the actual situation, thereby providing a scientific basis and technical support for the design and optimization of low-voltage power line carrier communication systems.

[0026] In some implementation schemes of the present invention, in S201, in the power line carrier communication channel model constructed based on the transmission line theory, the influence of channel noise and interference factors is not considered for the time being. Using MATLAB software, the channel models under three network topologies of bus type, tree type and daisy chain type are simulated and studied. The simulation results are presented in the form of amplitude-frequency response curves, and the average signal attenuation value in the specified frequency band is calculated to intuitively show the characteristic differences of the channels under different topological structures. It should be noted that in practical applications, power line networks usually present a complex multi-port structure, and the two-port network (2PN) is used as a basic unit. The power transmission lines inside it are considered to be evenly distributed, and the transmission constant and characteristic impedance can be calculated with the help of transmission line theory. For complex networks with more branches, the method of "branch lines are equivalent to parallel loads" is adopted. By iteratively adjusting the impedance of each sub-branch node, it is simplified to a parallel load form in order to calculate the overall transmission function. Based on this, channel modeling is performed on three typical topologies of bus type, tree type and daisy chain type, and simulation is performed using MATLAB software. The simulation results are displayed through the amplitude-frequency response curve and the average signal attenuation degree in the specified frequency band.

[0027] In some embodiments of the present invention, in S202, the power line carrier communication channel parameter measurement principle prototype is a complete and independently deployable low-voltage power line carrier communication system, consisting of a DC power supply, a signal processing board, a signal acquisition board, a power line carrier topology network, a spectrum analyzer, a host computer, etc., and has the ability to evaluate communication performance and measure channel attenuation.

[0028] The physical channel parameter measurement system for low-voltage power line carrier communication was built to test the direct attenuation of the system and the channel attenuation under different power line parameters. In order to compare the impact of different wiring layouts on channel characteristics under the three power line topologies of bus, tree, and daisy chain, the channel attenuation values ​​under different trunk lengths, different numbers of nodes, and different branch lengths were tested under each topology type.

[0029] In some embodiments of the present invention, in S203, the modified channel model introduces the attenuation of the measurement principle prototype itself and the attenuation caused by the power line topology network on the basis of the original transmission line model without adding external noise and interference, so as to compensate for the influence of channel interference and environmental noise. In this way, the model more accurately reflects the channel characteristics in the actual communication environment, and improves the practicality and reliability of the model.

[0030] In some implementation schemes of the present invention, in S203, the modified channel attenuation model comprehensively considers four factors: the original simulated channel attenuation, the prototype system's own attenuation, the topological trunk weighted attenuation, and the topological branch weighted attenuation. Among them, the weights of the trunk attenuation and the branch attenuation are obtained by applying a multivariate linear regression model based on the actual measurement data. This model is intended to more accurately reflect the channel attenuation in the actual communication environment and provide reliable theoretical support for the performance evaluation and optimization design of the power line carrier communication system. Specifically, the original simulated channel attenuation is the network signal attenuation calculated without adding interference and noise according to the specific topological structure, the electrical characteristics of the transmission line, the power line length, the load impedance and other basic channel parameters. This value is difficult to reflect the real channel characteristics, because there are multipath attenuation, attenuation caused by conjugate mismatch and channel noise in the real power line network, and the signal will be affected by these interferences and thus affect the communication quality. The basic transmission line model used in the present invention does not consider the noise and interference model, so the value obtained is the energy attenuation caused by signal transmission under ideal conditions. Specifically, the system's own attenuation refers to the signal strength weakening phenomenon caused by components such as the equipment and its connecting lines inside the system, excluding the influence of the power line topology network. This attenuation is due to the natural attenuation caused by factors such as impedance mismatch and line loss when the signal passes through these components.

[0031] Specifically, the attenuation of the power line topology network can be divided into two parts: trunk attenuation and branch attenuation. Through the analysis of measured data, it is found that the actual signal attenuation value of the power line topology network is not linearly related to the increase in the number of interface circuit boards and the length of the cable. In addition, in different types of topologies, the changes in the number of interface boards and the changes in cable length have different effects on signal attenuation. In view of this, when analyzing the attenuation of the power line topology network, it is subdivided into two parts: the attenuation caused by the trunk length and the attenuation caused by the branch nodes, so as to more accurately understand how various factors affect the transmission quality of the signal. This method helps to reveal the specific mechanism of signal attenuation under different topologies and provide a scientific basis for optimizing the design of communication systems.

[0032] More specifically, the modified channel attenuation model integrates four key factors: the initial simulated channel attenuation, the attenuation of the measurement system itself, the weighted attenuation of the topological structure trunk, and the weighted attenuation of the topological structure branch. Among them, the weights of the trunk and branch attenuation are determined by fitting the multivariate linear regression model using the actual measured data.

[0033]

[0034] Formula (1) shows the correction method of the channel attenuation model, where X is the simulated channel attenuation data, and Y is the channel attenuation data based on the actual measurement of the system. is the system's own attenuation value, obtained by direct test of the prototype. and are the total length of the trunk and the total length of the branches of the tested topology network, and The trunk length weight coefficient and branch length weight coefficient are fitted by the multivariate linear regression model respectively. By comparison, the influence of the trunk and branch on channel attenuation under each topology can be analyzed, and then the wiring suggestions that are more in line with the topology can be inferred.

[0035] In some embodiments of the present invention, by comparing and analyzing the modified channel attenuation models of the three topological structures of bus type, tree type and daisy chain type, it is found that in the bus topological structure, the influence of the trunk part on signal attenuation is significantly higher than that of the branch node part; in the tree topological structure, the channel attenuation coefficient of the trunk is also greater than the attenuation coefficient of the branch; in contrast, in the daisy chain structure, the influence of the branch on the overall attenuation of the system is more significant. The following conclusions are drawn: bus-type networks and tree-type networks are more suitable for circuit application scenarios with a large number of nodes. When the number of nodes is the same, the channel attenuation of the tree-type network is less than that of the bus-type network. Therefore, in multi-node application scenarios, the tree-type topology can be given priority. However, when the network has high requirements for communication distance, the daisy chain topology should be given priority because it performs better in long-distance communication. In some implementation schemes of the present invention, in S3, during the operation, the on-site staff can select a power line topology network structure suitable for the low-voltage power grid according to actual conditions.

[0036] A second aspect of the present invention discloses a low voltage power line carrier communication channel modeling device, comprising: A collection unit, used for acquiring global parameters of the low voltage power grid; A prediction unit, used for inputting global parameters into three power line topology network structures to obtain a predicted attenuation value of each power line topology network structure; the three power line topology network structures include a bus type network channel model, a tree type network channel model and a daisy chain type network channel model; The acquisition process of the three power line topology networks is as follows: based on the transmission line model, three power line topology networks are constructed for the experimental low-voltage power line network structure; the channel attenuation of the bus network channel model, the tree network channel model and the daisy chain network channel model are measured respectively; the three power line topology networks are corrected respectively in combination with the measured data to obtain the three power line topology networks; the correction items include the attenuation value of the system itself, the influence value of the trunk line in the topology network on the attenuation, and the influence value of the branch line on the attenuation; The confirmation unit is used to determine the power line topology network structure corresponding to the low-voltage power grid based on the attenuation value.

[0037] The third aspect of the present invention discloses a low voltage power line carrier communication channel modeling system for implementing the above modeling method, referring to Figure 5 The system can measure the attenuation value of each power line topology network when constructing three power line topology networks in the early stage. It can also directly connect the topology structure corresponding to the built low-voltage power grid to the location of the power line topology network in actual application to measure the attenuation value. Specifically including: The low-voltage power line carrier communication physical channel parameter measurement principle prototype consists of a DC power supply, a signal processing board, a signal acquisition board, a power line topology network, a spectrum analyzer and a host computer. The power line topology network mainly includes an interface circuit board and a low-voltage power cable, wherein the interface circuit board is responsible for transmitting the signal of the load node in the topology network to the signal acquisition board. Each interface circuit board is equipped with four interfaces, namely, a power input port, a load port, a signal test port and a reserved port. The 24 signal acquisition boards are respectively connected to the 24 load nodes of the power line network topology. By adjusting the connection status between each load, different network topologies can be formed. The signal acquisition board and the signal processing board are connected through an SMA interface.

[0038] The acquisition circuit on the signal acquisition board is composed of six signal acquisition modules with the same structure, which can realize the selection and up-conversion functions of multi-node signals. Each signal acquisition board is responsible for selecting one signal from the four input signals and outputting it to the signal processing board as its input. The six signal acquisition boards share a crystal oscillator with an oscillation frequency of 800MHz as the local oscillator signal source, and the bandwidth of the bandpass filter is set to 180MHz.

[0039] The signal processing board is developed based on the TMS320C6678 floating-point DSP of the C6000 series and the Xilinx Artix-7 FPGA core processor, and has six input ports and one output port. The six input ports receive signals from six signal acquisition boards, while the output port can provide multi-carrier modulation signals in the range of 10~30MHz or 70~90MHz for simulating signal sources.

[0040] The spectrum analyzer is used to monitor the signal attenuation value in the topology network, providing intuitive data support for the analysis of channel characteristics. The FPGA and DSP development environments of the system are Xilinx's Vivado 2017 and TI's CodeComposer Studio 5.5.0, respectively, to ensure the efficiency of the collaborative work of software and hardware.

[0041] In the actual test process, the transmitter uses the test instrument to generate an analog signal source, which is input into the power line topology network through the interface circuit board, and a 30V DC voltage is provided by the DC power supply. After the 24 baseband signals enter the signal acquisition board, they are selected and up-converted and converted into six signals as the input of the signal processing board. After the signal processing board completes further signal processing, the computer extracts parameters and estimates channels of the processed signals, and displays channel characteristics through the Vivado platform and spectrum analyzer, providing strong support for the performance evaluation and optimization of the low-voltage power line carrier communication system.

[0042] A specific implementation example and a specific test example can be given later. It would be best if there are some simulation diagrams, or the presentation and comparison of data accuracy data.

[0043] Example 1 In this embodiment, a comparison of the data of the prototype measured and the modified simulation model in different topology types is given. From the test verification results, it can be seen that the error between the channel model simulation attenuation value and the measured channel attenuation value of the bus, tree, and daisy chain topology networks is less than 20%.

[0044] Table 1 Bus network test results

[0045] Table 2 Tree network test results

[0046] Table 3 Daisy chain network test

[0047] Example 2 Assume that there are currently the following communication requirements: the communication distance is 100m, the number of communication nodes in the system is 10, the distribution of each communication node in the system is relatively uniform, and the branch length of each communication node (that is, the distance from the communication trunk) is less than 3m. Under this communication requirement, the low-voltage power line carrier communication channel modeling device described in the second aspect of the present invention is used to simulate and study the three topological structures respectively, and compare the channel characteristics.

[0048] Enter the power line parameters in the bus type, tree type, daisy chain type and other topologies as required. In the bus type topology, according to the evenly distributed wiring requirements, a node can be set every 10m on the 100m trunk. According to the structural characteristics of the bus type topology, each node is connected to a branch, and the branch length can be set at will. In this example, the branch length is mostly set to 1m and 2m. A node in the tree type topology contains multiple secondary branches, so 5 nodes are set at equal distances on the trunk line, and 2 secondary branches are set on each node. Similarly, the branch length is mostly 1m and 2m. The daisy chain topology can be set to a three-chain type, and the lengths of the three links are set to 40m, 40m, and 20m respectively. 4, 4, and 2 nodes are set on the three links respectively, and the node branch lengths are also mostly set to 1m and 2m.

[0049] The results are as follows Figure 6 , Figure 7 and Figure 8As shown. In the result evaluation module, you can read the channel attenuation value. The bus attenuation is about -43.04dB, the tree attenuation is -18.78dB, and the daisy chain attenuation is about -27.95dB. In this example, there are many communication nodes in the topology network, and the channel attenuation value of the tree topology is the most ideal, so the tree structure can be given priority.

[0050] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A low voltage power line carrier communication channel modeling method, characterized in that: The following steps are involved: S1, obtaining global parameters of the low voltage power grid; S2, inputting the global parameters into three power line topology network structures to obtain a predicted attenuation value of each power line topology network structure; the three power line topology network structures include a bus type network channel model, a tree type network channel model and a daisy chain type network channel model; The acquisition process of the three power line topology networks is as follows: based on the transmission line model, three power line topology networks are constructed for the experimental low-voltage power line network structure; the channel attenuation of the bus type network channel model, the tree type network channel model and the daisy chain type network channel model are measured respectively; The three power line topology networks are corrected by correction items in combination with the measured data to obtain the three power line topology networks; the correction items include the attenuation value of the system itself, the influence value of the main line on the attenuation in the topology network, and the influence value of the branch line on the attenuation; S3, determining a power line topology network structure corresponding to the low voltage power grid based on the attenuation value.

2. A low voltage power line carrier communication channel modeling method according to claim 1, characterized in that: In S1, the global parameters of the low-voltage power grid include power line distribution parameters and load organization; the power line distribution parameters include resistance, inductance, capacitance and conductance values ​​per unit length of a uniform power transmission line.

3. A low voltage power line carrier communication channel modeling method according to claim 1, characterized in that: In S2, during the construction of the three power line topology networks, channel noise and interference factors are ignored, and the impedance of each branch node is adjusted by using a method in which the branch lines are equivalent to parallel loads.

4. A low voltage power line carrier communication channel modeling method according to claim 1, characterized in that: In S2, the measurement result of the power line topology network is presented in the form of an amplitude-frequency response curve.

5. A low voltage power line carrier communication channel modeling method according to claim 1, characterized in that: In S2, the formulas for correcting the three power line topology networks respectively in combination with the measured data are: Among them, X is the simulated channel attenuation data, and Y is the channel attenuation data based on the actual measurement of the system. is the system's own attenuation value, and are the total length of the trunk and the total length of the branches of the tested topology network, and The trunk length weight coefficient and branch length weight coefficient are fitted by the multivariate linear regression model respectively.

6. A low voltage power line carrier communication channel modeling method according to claim 5, characterized in that: The system's own attenuation refers to the weakening of signal strength caused by the devices and connecting lines within the system.

7. A low voltage power line carrier communication channel modeling method according to claim 5, characterized in that: The trunk length weight coefficient and the branch length weight coefficient are obtained through a multiple linear regression model, and the multiple linear regression model is obtained based on actual measurement data.

8. A low voltage power line carrier communication channel modeling method according to claim 1, characterized in that: In S3, the bus-type network channel model is applicable to a low-voltage power grid with multiple nodes, the tree-type network channel model is applicable to a low-voltage power grid with an equal number of nodes, and the daisy-chain-type network channel model is applicable to a low-voltage power grid with a long communication distance.

9. A low voltage power line carrier communication channel modeling device, characterized in that: include: A collection unit, used for acquiring global parameters of the low voltage power grid; A prediction unit, used for inputting global parameters into three power line topology network structures to obtain a predicted attenuation value of each power line topology network structure; the three power line topology network structures include a bus type network channel model, a tree type network channel model and a daisy chain type network channel model; The acquisition process of the three power line topology networks is as follows: based on the transmission line model, three power line topology networks are constructed for the experimental low-voltage power line network structure; the channel attenuation of the bus network channel model, the tree network channel model and the daisy chain network channel model are measured respectively; the three power line topology networks are corrected respectively in combination with the measured data to obtain the three power line topology networks; the correction items include the attenuation value of the system itself, the influence value of the trunk line in the topology network on the attenuation, and the influence value of the branch line on the attenuation; The confirmation unit is used to determine the power line topology network structure corresponding to the low-voltage power grid based on the attenuation value.

10. A low voltage power line carrier communication channel modeling system for implementing the modeling method of claim 1, characterized in that: It includes a DC power supply, a spectrum analyzer, a signal acquisition board, a signal processor and a host computer; the DC power supply, the spectrum analyzer and the signal acquisition board are simultaneously connected to the power line topology network structure with electrical signals, the signal acquisition board is connected to the signal processor with electrical signals, and the signal processor is connected to the host computer with electrical signals.

Images