A three-phase current compensation method and compensation system

Abstract

The present invention provides a three-phase current compensation method and compensation system, which belong to the field of smart grid technology. By collecting the current three-phase current at the location of each SVG unit and using a pre-trained prediction model to predict the future unbalanced amount, the early prediction of future compensation needs is achieved. At the same time, the central controller generates a compensation current instruction including current instructions and future instructions according to the operating parameters and prediction results of each SVG unit, ensuring that each SVG unit can work together to complete the compensation task of the three-phase unbalanced current, solving the problems of limited compensation effect and lack of collaborative control mechanism in the existing three-phase current compensation method, improving the three-phase balance of the power system, and ensuring the safe and stable operation of the power grid.

Description

Technical Field

[0001] The present invention relates to the technical field of smart grids, and in particular to a three-phase current compensation method and a compensation system. Background Art

[0002] In the power system, the balance of three-phase current is one of the key factors to ensure the stable operation of the power grid and the quality of power. However, in actual operation, due to the influence of various factors, such as the existence of a large number of single-phase loads, the asynchronous start and stop of electrical equipment, and the unbalanced characteristics of specific loads such as electrified railways and AC arc furnaces, the three-phase current imbalance phenomenon is common. This imbalance will not only lead to an increase in negative sequence current in the power grid, but may also cause a series of problems such as equipment overheating, voltage fluctuations, and power factor reduction, which seriously affect the safety and economy of the power system.

[0003] Traditional three-phase current compensation methods mainly rely on distribution companies to make the loads of each phase as symmetrical as possible when installing distribution equipment, and to reduce three-phase imbalance by reasonably arranging the load operation time, etc. However, since users' electricity consumption behavior is difficult to predict and changes frequently, these methods have limited effects in practical applications and it is difficult to completely solve the three-phase imbalance problem.

[0004] Therefore, it is necessary to provide a three-phase current compensation method and compensation system to solve the above technical problems. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a three-phase current compensation method and compensation system, which not only improves the accuracy and efficiency of compensation, but also enhances the flexibility and scalability of the system by adopting a central controller and multiple SVG units to work together.

[0006] The present invention provides a three-phase current compensation method, which is configured with a central controller and a plurality of SVG units that perform data communication with the central controller, wherein the central controller is used to distribute compensation instructions to the plurality of SVG units to achieve collaborative operation among the plurality of SVG units to complete compensation of three-phase unbalanced current. The compensation method comprises the following steps:

[0007] Collecting the current three-phase current at the location of each SVG unit, and when detecting that the current three-phase current is unbalanced, calculating the current unbalance amount to be compensated;

[0008] Input the current three-phase current into a pre-trained prediction model to perform imbalance prediction at a prediction time, and output a prediction result, wherein the prediction result is a future imbalance amount to be compensated;

[0009] Based on the operating parameters of each SVG unit, the central controller generates a compensation current instruction for each SVG unit according to the future unbalance amount to be compensated and the current unbalance amount, wherein the compensation current instruction includes a current instruction and a future instruction;

[0010] According to the current instruction, the SVG unit generates a first current compensation current to offset the current unbalanced amount of the current three-phase current;

[0011] According to the future instruction, the SVG unit generates a future compensation current and waits, and when the predicted time is reached, determines whether the current instruction newly generated at the predicted time is consistent with the future instruction. If they are consistent, compensation is performed according to the future compensation current. If they are not consistent, the SVG unit regenerates a second current compensation current for compensation according to the current instruction newly generated at the predicted time.

[0012] Preferably, the collecting of the current three-phase current at the location of each SVG unit and, when it is detected that the current three-phase current is unbalanced, calculating the current unbalance amount to be compensated includes:

[0013] Each SVG unit monitors the instantaneous value of the three-phase current at its location and transmits it to the central controller for preliminary processing;

[0014] In the central controller, identifying whether there is an imbalance by a symmetrical component method;

[0015] When it is detected that the current three-phase current is unbalanced, the current unbalance amount to be compensated is calculated based on the instantaneous power theory method.

[0016] Preferably, the calculation of the current imbalance amount to be compensated based on the instantaneous power theory method includes:

[0017] The instantaneous value of the three-phase current is converted into the current I in the two-phase stationary coordinate system by Clarke transformation. d and current I q , the formula for Clarke transformation is:

[0018]

[0019] Among them, I0 represents the zero sequence component, I a ,I b and I c Represents the current of phase A, phase B and phase C;

[0020] Using Park transformation, the current I d and current I q Converted to the rotating coordinate system, we get the positive sequence component and the negative sequence component, where the Clarke transformation formula is:

[0021]

[0022] Among them, I d+ and I q+ is the positive sequence component, I d- and I q- is the negative sequence component, ω is the fundamental angular frequency, and t is time;

[0023] The current unbalanced value I is calculated based on the negative sequence component, and the calculation formula is:

[0024]

[0025] Preferably, the inputting the current three-phase current into a pre-trained prediction model to perform imbalance prediction at a prediction time, and outputting a prediction result, wherein the prediction result is a future imbalance amount to be compensated, including:

[0026] Extracting the unbalanced characteristics of the current three-phase current;

[0027] The unbalanced characteristics of the current three-phase current are input into the prediction model for prediction, and a prediction result including the future unbalanced amount to be compensated is output, wherein the prediction model is a neural network model trained by historical data.

[0028] Preferably, based on the operating parameters of each SVG unit, the central controller generates a compensation current instruction for each SVG unit according to the future imbalance amount to be compensated and the current imbalance amount, including:

[0029] Collecting real-time operating parameters from all SVG units through the central controller;

[0030] Based on the operating parameters of each SVG unit, the central controller uses a distributed allocation strategy to allocate the current unbalanced amount to each SVG unit and obtains the allocation result;

[0031] generating a current instruction for each SVG unit based on the allocation result;

[0032] Future instructions are generated for each SVG unit based on the future imbalance amount to be compensated.

[0033] Preferably, the generation of the first current compensation current, the future compensation current and the second current compensation current all include:

[0034] The SVG unit receives and decodes the compensation current instruction from the central controller;

[0035] Convert the decoded compensation current command into a PWM signal;

[0036] Based on the converted PWM signal, the SVG unit is controlled to generate the required first current compensation current, future compensation current or second current compensation current.

[0037] Preferably, a numerical comparison method is used to determine whether the current instruction newly generated at the prediction time is consistent with the future instruction.

[0038] Preferably, the first current compensation current, the second current compensation current and the future compensation current all include current magnitude, current direction and phase.

[0039] The present invention also provides a three-phase current compensation system for executing a three-phase current compensation method, which is configured with a central controller and a plurality of SVG units communicating with the central controller, wherein the central controller is used to distribute compensation instructions to the plurality of SVG units to achieve collaborative operation among the plurality of SVG units to complete compensation of three-phase unbalanced current. The compensation system includes:

[0040] An unbalance quantification module is used to collect the current three-phase current at the location of each SVG unit, and when it is detected that the current three-phase current is unbalanced, calculate the current unbalance amount to be compensated;

[0041] An unbalance prediction module, used for inputting the current three-phase current into a pre-trained prediction model to perform unbalance prediction at a prediction time, and outputting a prediction result, wherein the prediction result is a future unbalance amount to be compensated;

[0042] A compensation instruction generation module, which is used for generating a compensation current instruction of each SVG unit based on the operating parameters of each SVG unit and the central controller according to the future unbalance amount to be compensated and the current unbalance amount, wherein the compensation current instruction includes a current instruction and a future instruction;

[0043] An instant compensation execution module, configured to cause the SVG unit to generate a first current compensation current according to the current instruction to offset a current unbalanced amount of the current three-phase current;

[0044] The future compensation adjustment module is used to generate a future compensation current and wait for the SVG unit according to the future instruction, and when the predicted time is reached, determine whether the current instruction newly generated at the predicted time is consistent with the future instruction. If they are consistent, compensation is performed according to the future compensation current. If they are not consistent, the SVG unit regenerates a second current compensation current for compensation according to the current instruction newly generated at the predicted time.

[0045] Compared with the related art, the three-phase current compensation method and compensation system provided by the present invention have the following beneficial effects:

[0046] The present invention collects the current three-phase current at the location of each SVG unit and uses a pre-trained prediction model to predict the future unbalanced amount, thereby realizing early prediction of future compensation needs. At the same time, the central controller generates compensation current instructions including current instructions and future instructions according to the operating parameters and prediction results of each SVG unit, ensuring that each SVG unit can work together to complete the compensation task of the three-phase unbalanced current, solving the problems of limited compensation effect and lack of collaborative control mechanism in the existing three-phase current compensation method, improving the three-phase balance of the power system, and ensuring the safe and stable operation of the power grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 A flow chart of a three-phase current compensation method provided by the present invention;

[0048] Figure 2 A module structure diagram of a three-phase current compensation system provided by the present invention. DETAILED DESCRIPTION

[0049] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only the parts related to the present invention, rather than all structures, are shown in the accompanying drawings. In addition, the embodiments of the present invention and the features in the embodiments may be combined with each other without conflict.

[0050] It should also be noted that, for ease of description, only the part relevant to the present invention but not all the content is shown in the accompanying drawings. It should be mentioned before discussing the exemplary embodiments in more detail that some exemplary embodiments are described as the processing or method described as a flow chart. Although the flow chart describes each operation (or step) as being processed sequentially, many operations therein can be implemented in parallel, concurrently or simultaneously. In addition, the order of each operation can be rearranged. When its operation is completed, the processing can be terminated, but it can also have additional steps not included in the accompanying drawings. The processing can correspond to a method, a function, a procedure, a subroutine, a subprogram, etc.

[0051] Embodiment 1

[0052] The present invention provides a three-phase current compensation method, which is configured with a central controller and a plurality of SVG units communicating with the central controller, wherein the central controller is used to distribute compensation instructions to the plurality of SVG units, so as to realize the collaborative operation among the plurality of SVG units to complete the compensation of the three-phase unbalanced current, with reference to Figure 1 As shown, the compensation method includes the following steps:

[0053] S1: collecting the current three-phase current at the location of each SVG unit, and when detecting that the current three-phase current is unbalanced, calculating the current unbalance amount to be compensated.

[0054] In this embodiment, first, each SVG (static var generator) unit continuously monitors the current of the three-phase grid through its built-in current sensor. These current sensors can capture the current waveforms of the three phases A, B, and C in real time, convert the analog signals into digital signals, and transmit them to the central controller through the data bus. After receiving these data, the central controller uses the symmetrical component method to analyze the three-phase current and identify whether there is an imbalance. Once an imbalance is detected, the central controller will start the imbalance calculation program and calculate the unbalanced current according to the imbalance definition formula, thereby determining the imbalance amount that needs to be compensated.

[0055] S2: Input the current three-phase current into a pre-trained prediction model to perform imbalance prediction at a prediction time, and output a prediction result, wherein the prediction result is a future imbalance amount that needs to be compensated.

[0056] In this embodiment, the central controller takes the acquired current three-phase current as input and sends it to a pre-trained machine learning model (such as a deep neural network). This model has been trained with a large amount of historical current three-phase current data and can predict the imbalance that may occur at a specific time point in the future. By predicting the future imbalance, compensation preparations can be made in advance, avoiding insufficient or excessive compensation due to response lag, and improving the accuracy of compensation and the stability of the system.

[0057] S3: Based on the operating parameters of each SVG unit, the central controller generates a compensation current instruction for each SVG unit according to the future imbalance amount to be compensated and the current imbalance amount, wherein the compensation current instruction includes a current instruction and a future instruction.

[0058] In this embodiment, the central controller comprehensively considers the operating parameters of the SVG unit and calculates the optimal compensation strategy. For the current unbalanced amount, a compensation current instruction is immediately generated and allocated to each SVG unit; for the future unbalanced amount, a future compensation instruction is generated and stored for standby use. The compensation current instruction contains the compensation current including the size, phase, direction and ID of the SVG unit, ensuring that the compensation current is accurately applied to the power grid. By dynamically allocating compensation resources, the intelligent scheduling of the SVG unit is realized, which not only meets the immediate compensation needs, but also reserves space for future imbalance compensation, enhancing the flexibility and economy of the system.

[0059] S4: According to the current instruction, the SVG unit generates a first current compensation current to offset the current unbalanced amount of the current three-phase current.

[0060] In this embodiment, after receiving the current instruction issued by the central controller, each SVG unit responds quickly, adjusts the control parameters of its internal inverter, generates a first current compensation current that is equal to the unbalanced current in magnitude and opposite in phase, and injects it into the power grid in real time to offset the impact of the unbalanced current. By instantly generating the compensation current, the current unbalanced state is quickly corrected, effectively reducing the risk of power quality deterioration and equipment damage.

[0061] S5: According to the future instruction, the SVG unit generates a future compensation current and waits, and when the predicted time is reached, determines whether the current instruction newly generated at the predicted time is consistent with the future instruction. If they are consistent, compensation is performed according to the future compensation current. If they are not consistent, the SVG unit regenerates a second current compensation current for compensation according to the current instruction newly generated at the predicted time.

[0062] In this embodiment, after receiving the future compensation instruction, the SVG unit prepares the compensation current in advance, but remains in standby mode before the actual compensation. When the predicted time point is reached, the central controller re-evaluates the grid status. If it is found that the current imbalance is consistent with the predicted future imbalance, the SVG unit will release the future compensation current as planned, and the process of recalculating the compensation current can be omitted, and the prepared future compensation current can be directly used, thereby saving computing resources; conversely, if the prediction is inconsistent with the actual situation, the central controller will recalculate the compensation instruction, and the SVG unit will generate a new compensation current according to the latest current instruction, that is, the second current compensation current, to ensure the accuracy and timeliness of the compensation.

[0063] Specifically, step S1 includes the following steps:

[0064] Step 101: Each SVG unit monitors the instantaneous value of the three-phase current at its location and transmits it to the central controller for preliminary processing.

[0065] In this embodiment, each SVG unit is equipped with a current transformer, which is connected to the three-phase lines A, B, and C to continuously measure the instantaneous value of the three-phase current. The measured data is converted into a digital signal by an analog-to-digital converter (ADC) and then transmitted to the central controller via a high-speed data bus. At the central controller end, these data are temporarily stored in a buffer for subsequent processing.

[0066] Step 102: In the central controller, identify whether there is an imbalance by using a symmetrical component method.

[0067] In this embodiment, after receiving the three-phase current data, the central controller uses the symmetrical component method to analyze the data. Specifically, the symmetrical component method decomposes the three-phase current into positive sequence, negative sequence and zero sequence components. The positive sequence component represents a balanced state, while the presence of negative sequence and zero sequence components indicates that the three-phase current is unbalanced. By calculating the magnitude of the negative sequence and zero sequence components, the central controller can determine whether there is an unbalance phenomenon.

[0068] Step 103: When it is detected that the current three-phase current is unbalanced, the current unbalance amount to be compensated is calculated based on the instantaneous power theory method.

[0069] In this embodiment, once the imbalance is confirmed, the central controller will use the instantaneous power theory for further analysis. The instantaneous power theory allows the calculation of instantaneous active power and reactive power, and then determines the amount of imbalance. The central controller calculates the magnitude and phase of the unbalanced current, as well as the direction and magnitude of the required compensation current to achieve the balance of the three-phase current, which can not only effectively eliminate the unbalanced current, but also improve the power quality and system efficiency, reduce equipment loss, and extend service life.

[0070] Specifically, step 103 includes the following steps:

[0071] First, the instantaneous value of the three-phase current is converted into the current I in the two-phase stationary coordinate system by Clarke transformation. d and current I q , the formula for Clarke transformation is:

[0072]

[0073] Among them, I0 represents the zero sequence component, I a ,I b and I c Represents the current of phase A, phase B and phase C.

[0074] Secondly, the Park transformation is used to convert the current I d and current I q Converted to the rotating coordinate system, we get the positive sequence component and the negative sequence component, where the Clarke transformation formula is:

[0075]

[0076] Among them, I d+ and I q+ is the positive sequence component, I d- and I q- is the negative sequence component, ω is the fundamental angular frequency, and t is time.

[0077] Finally, the current unbalanced value I is calculated based on the negative sequence component, and the calculation formula is:

[0078]

[0079] In this embodiment, the above process converts the three-phase current signal into a coordinate system that is convenient for analyzing imbalance by using Clarke transformation and Park transformation, thereby accurately identifying and quantifying the degree of imbalance in the three-phase system, which not only simplifies the complexity of imbalance detection, but also improves the accuracy and real-time performance of detection, and provides key data support for subsequent compensation operations.

[0080] Specifically, step S2 includes the following steps:

[0081] Step S201: extracting the unbalanced characteristics of the current three-phase current.

[0082] In this embodiment, key features reflecting the unbalanced state need to be extracted from the current three-phase current data, wherein the unbalanced features include but are not limited to the ratio of positive sequence components to negative sequence components, the difference between the currents of each phase, the frequency deviation, and the harmonic content. The selection of these features should be based on their sensitivity to the unbalanced state and their predictive ability.

[0083] Step S202: inputting the unbalanced characteristics of the current three-phase current into the prediction model for prediction, and outputting a prediction result including a future unbalanced amount to be compensated, wherein the prediction model is a neural network model trained by historical data.

[0084] In this embodiment, after the imbalance features are collected, the next step is to input these features into a pre-trained prediction model. The prediction model is usually a neural network model, which is trained with a large amount of historical data to learn the mapping relationship between the imbalance features and the future imbalance amount.

[0085] The training process of the prediction model includes:

[0086] Data preprocessing: clean and normalize historical data to ensure data quality and consistency.

[0087] Feature engineering: Select or construct the features that best reflect the unbalanced state, including but not limited to the ratio of positive-sequence components to negative-sequence components, the difference between phase currents, frequency deviation, and unbalanced features of harmonic content.

[0088] Model training: Use a deep learning framework to train the model and optimize the weight parameters through the back-propagation algorithm to minimize the prediction error.

[0089] Model Validation: Evaluate model performance through cross-validation to ensure that the model has good generalization ability.

[0090] Once the model training is complete, it can be used for real-time prediction. In the prediction stage, the imbalance features extracted at the current moment are used as input, and the model outputs a prediction result, which includes the future imbalance amount that needs to be compensated within the prediction time period.

[0091] Specifically, step S3 includes the following steps:

[0092] Step S301: collecting real-time operating parameters from all SVG units through the central controller.

[0093] In this embodiment, the working status of all static VAR generator (SVG) units is monitored in real time. The central controller serves as the core and is responsible for periodically collecting a series of key operating parameters from each SVG unit, including but not limited to the current output power, temperature, voltage, current, and working status of the SVG. These parameters provide information on whether the SVG unit is operating normally and its adjustable capacity.

[0094] Step S302: Based on the operating parameters of each SVG unit, the central controller distributes the current unbalanced amount to each SVG unit using a distributed allocation strategy to obtain an allocation result.

[0095] In this embodiment, after collecting the operating parameters of all SVG units, the central controller determines how to decompose the currently detected imbalance according to the distributed allocation strategy and assigns it to each SVG unit for compensation. This strategy needs to consider factors such as the available capacity, geographical location, and response speed of the SVG unit to achieve the overall optimal compensation effect.

[0096] For example, assuming that the current unbalance detected is ΔQ, and there are three SVG units A, B, and C, whose remaining compensation capacities are QA, QB, and QC respectively, based on the proportional allocation strategy of the remaining capacity, the central controller will allocate the unbalance in proportion, that is:

[0097] SVGA allocation = (QA / (QA+QB+QC))*ΔQ

[0098] SVG B distribution amount = (QB / (QA+QB+QC))*ΔQ

[0099] SVG C distribution amount = (QC / (QA+QB+QC))*ΔQ

[0100] This strategy ensures that all SVG units share the imbalance according to their maximum compensation capabilities, avoiding the situation where some units are overused while others are idle.

[0101] Step S303: Generate a current instruction for each SVG unit based on the allocation result.

[0102] In this embodiment, based on the allocation result obtained in the previous step, the central controller generates precise control instructions for each SVG unit, indicating the compensation current it should output. Specifically:

[0103] Current instruction refinement: The total compensation demand is converted into specific operation instructions for each SVG unit, that is, adjusting the size, direction and phase of the output current.

[0104] Safety check: Ensures that the current instructions generated do not cause the SVG unit to exceed its safe operating range.

[0105] Instruction issuance: The current instruction is sent to each SVG unit through the communication link to ensure that the instruction is executed promptly and accurately.

[0106] Step S304: Generate future instructions for each SVG unit based on the future imbalance amount to be compensated.

[0107] In this embodiment, in addition to processing the current imbalance situation, it is also necessary to use the future imbalance output by the prediction model to plan compensation measures in advance and generate future instructions for each SVG unit, so that resources can be mobilized in advance to ensure a quick response when an imbalance occurs.

[0108] In this embodiment, the process of generating future instructions may include:

[0109] Prediction integration: Combining the future imbalances given by the prediction model with the current state and capacity of the SVG unit.

[0110] Plan formulation: Based on the prediction results, a compensation plan is formulated, including which SVG units will participate in the compensation, as well as their respective compensation amounts and time points.

[0111] Instruction preset: These plans are converted into specific instruction sequences, stored in the central controller, and executed at the predetermined time point based on the matching judgment results.

[0112] Specifically, the generation of the first current compensation current, the future compensation current, and the second current compensation current all include:

[0113] The SVG unit receives and decodes compensation current instructions from the central controller.

[0114] The decoded compensation current command is converted into a PWM signal.

[0115] Based on the converted PWM signal, the SVG unit is controlled to generate the required first current compensation current, future compensation current or second current compensation current.

[0116] In this embodiment, the generation of the first current compensation current, the future compensation current and the second current compensation current is specifically as follows:

[0117] First, the compensation current command is received and decoded.

[0118] Communication protocol: The SVG unit establishes a connection with the central controller through a pre-set communication interface. The central controller calculates the required compensation current command based on the current state and forecast of the power system and sends it to the SVG unit through the communication interface.

[0119] Decoding: After the SVG unit receives the instruction, it first needs to decode it. The decoding process involves converting the received binary data into an understandable instruction format, which may include but is not limited to the magnitude and phase of the compensation current and whether it is current compensation, future compensation or second current compensation.

[0120] Secondly, it is converted into a PWM signal.

[0121] Instruction parsing and calculation: The decoded compensation current instruction is further parsed, and the control circuit of the SVG unit calculates the corresponding PWM according to the instruction requirements. The PWM signal is a digital signal used to control the amplitude and frequency of the inverter output voltage, and then control the compensation current of the SVG unit.

[0122] PWM signal generation: The control circuit generates a series of PWM signals based on the calculation results. The characteristics of these signals are that within a certain period, by adjusting the width of the pulse to control the on and off time of the inverter switch device, thereby adjusting the output voltage and ultimately affecting the compensation current of the SVG unit.

[0123] Finally, the SVG unit is controlled to generate a compensation current.

[0124] Inverter control: The PWM signal is sent to the inverter control module of the SVG unit. The switching devices (such as IGBT) in the inverter perform rapid on and off operations according to the instructions of the PWM signal, converting DC power into AC power of specific frequency and amplitude.

[0125] Compensation current generation: The alternating current passes through the filtering and output circuit of the SVG unit, and finally generates the required first current compensation current, future compensation current or second current compensation current in the power system.

[0126] In addition, the first current compensation current, the second current compensation current and the future compensation current all include current magnitude, current direction and phase.

[0127] Specifically, a numerical comparison method is used to determine whether the current instruction newly generated at the prediction time is consistent with the future instruction.

[0128] In this embodiment, the steps of the numerical comparison method include:

[0129] Read data: Read the value of the current instruction newly generated at the prediction time.

[0130] Get predicted value: Get the previously predicted future instruction value.

[0131] Execution comparison: Compare the value of the current instruction newly generated at the predicted time with the predicted future instruction value.

[0132] If the values ​​are the same, the instructions are considered to match.

[0133] If the values ​​are different, the instructions are considered inconsistent.

[0134] The working principle of a three-phase current compensation method provided by the present invention is as follows: by collecting the current three-phase current at the location of each SVG unit and using a pre-trained prediction model to predict the future unbalanced amount, early prediction of future compensation needs is achieved. At the same time, the central controller generates a compensation current instruction including current instructions and future instructions according to the operating parameters and prediction results of each SVG unit, ensuring that each SVG unit can work together to complete the compensation task of the three-phase unbalanced current, solving the problems of limited compensation effect and lack of collaborative control mechanism in the existing three-phase current compensation method, improving the three-phase balance of the power system, and ensuring the safe and stable operation of the power grid.

[0135] Embodiment 2

[0136] The present invention also provides a three-phase current compensation system for executing a three-phase current compensation method, which is configured with a central controller and a plurality of SVG units communicating with the central controller, wherein the central controller is used to distribute compensation instructions to the plurality of SVG units to achieve collaborative operation among the plurality of SVG units to complete compensation of the three-phase unbalanced current, with reference to Figure 2 As shown, the compensation system includes:

[0137] The unbalance quantification module 100 is used to collect the current three-phase current at the location of each SVG unit, and when it is detected that the current three-phase current is unbalanced, calculate the current unbalance amount to be compensated.

[0138] The imbalance prediction module 200 is used to input the current three-phase current into a pre-trained prediction model to perform imbalance prediction at a prediction time and output a prediction result, wherein the prediction result is a future imbalance amount to be compensated.

[0139] The compensation instruction generation module 300 is used to generate compensation current instructions for each SVG unit based on the operating parameters of each SVG unit. The central controller generates compensation current instructions for each SVG unit according to the future imbalance amount to be compensated and the current imbalance amount, wherein the compensation current instruction includes a current instruction and a future instruction.

[0140] The instant compensation execution module 400 is used for the SVG unit to generate a first current compensation current according to the current instruction to offset the current unbalanced amount of the current three-phase current.

[0141] The future compensation adjustment module 500 is used to generate a future compensation current and wait for the SVG unit according to the future instruction, and when the predicted time is reached, determine whether the current instruction newly generated at the predicted time is consistent with the future instruction. If they are consistent, compensation is performed according to the future compensation current. If they are not consistent, the SVG unit regenerates a second current compensation current for compensation according to the current instruction newly generated at the predicted time.

[0142] The present application is described with reference to flowcharts and / or block diagrams of methods, devices (systems) and computer program products according to embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0143] A person skilled in the art can understand that all or part of the steps in the various methods of the above embodiments can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium, and the storage medium includes a read-only memory (ROM), a random access memory (RAM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), a one-time programmable read-only memory (OTPROM), an electronically erasable rewritable read-only memory (EEPROM), a compact disc (CD-ROM) or other optical disc storage, magnetic disk storage, magnetic tape storage, or any other computer-readable medium that can be used to carry or store data.

[0144] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device that includes a series of elements includes not only those elements, but also other elements that are not explicitly listed, or includes elements that are inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device that includes the elements.

Claims

1. A three-phase current compensation method, comprising a central controller and a plurality of SVG units communicating with the central controller, wherein: The central controller is used to distribute compensation instructions to multiple SVG units to achieve collaborative operation among the multiple SVG units to complete the compensation of three-phase unbalanced current. The compensation method includes the following steps: Collecting the current three-phase current at the location of each SVG unit, and when detecting that the current three-phase current is unbalanced, calculating the current unbalance amount to be compensated; Input the current three-phase current into a pre-trained prediction model to perform imbalance prediction at a prediction time, and output a prediction result, wherein the prediction result is a future imbalance amount to be compensated; Based on the operating parameters of each SVG unit, the central controller generates a compensation current instruction for each SVG unit according to the future unbalance amount to be compensated and the current unbalance amount, wherein the compensation current instruction includes a current instruction and a future instruction; According to the current instruction, the SVG unit generates a first current compensation current to offset the current unbalanced amount of the current three-phase current; According to the future instruction, the SVG unit generates a future compensation current and waits, and when the predicted time is reached, determines whether the current instruction newly generated at the predicted time is consistent with the future instruction, if consistent, performs compensation according to the future compensation current, if not consistent, the SVG unit regenerates a second current compensation current for compensation according to the current instruction newly generated at the predicted time; The collecting of the current three-phase current at the location of each SVG unit and, when detecting that the current three-phase current is unbalanced, calculating the current unbalance amount to be compensated includes: Each SVG unit monitors the instantaneous value of the three-phase current at its location and transmits it to the central controller for preliminary processing; In the central controller, identifying whether there is an imbalance by a symmetrical component method; When it is detected that the current three-phase current is unbalanced, the current unbalance amount to be compensated is calculated based on the instantaneous power theory method; The calculation of the current unbalance amount to be compensated based on the instantaneous power theory method includes: The instantaneous value of the three-phase current is converted into the current I in the two-phase stationary coordinate system by Clarke transformation. d and current I q , the formula for Clarke transformation is: Among them, I0 represents the zero sequence component, I a ,I b and I c Represents the current of phase A, phase B and phase C; Using Park transformation, the current I d and current I q Converted to the rotating coordinate system, we get the positive sequence component and the negative sequence component, where the Clarke transformation formula is: Among them, I d+ and I q+ is the positive sequence component, I d- and I q- is the negative sequence component, ω is the fundamental angular frequency, and t is time; The current unbalanced value I is calculated based on the negative sequence component, and the calculation formula is:

2. A three-phase current compensation method according to claim 1, characterized in that: The inputting the current three-phase current into the pre-trained prediction model to perform imbalance prediction at the prediction time, and outputting a prediction result, wherein the prediction result is a future imbalance amount to be compensated, including: Extracting the unbalanced characteristics of the current three-phase current; The unbalanced characteristics of the current three-phase current are input into the prediction model for prediction, and a prediction result including the future unbalanced amount to be compensated is output, wherein the prediction model is a neural network model trained by historical data.

3. A three-phase current compensation method according to claim 2, characterized in that: Based on the operating parameters of each SVG unit, the central controller generates a compensation current instruction for each SVG unit according to the future unbalance amount to be compensated and the current unbalance amount, including: Collecting real-time operating parameters from all SVG units through the central controller; Based on the operating parameters of each SVG unit, the central controller uses a distributed allocation strategy to allocate the current unbalanced amount to each SVG unit and obtains the allocation result; generating a current instruction for each SVG unit based on the allocation result; Future instructions are generated for each SVG unit based on the future imbalance amount to be compensated.

4. A three-phase current compensation method according to claim 3, characterized in that: The generation of the first current compensation current, the future compensation current, and the second current compensation current all include: The SVG unit receives and decodes the compensation current instruction from the central controller; Convert the decoded compensation current command into a PWM signal; Based on the converted PWM signal, the SVG unit is controlled to generate the required first current compensation current, future compensation current or second current compensation current.

5. A three-phase current compensation method according to claim 4, characterized in that: The numerical comparison method is used to determine whether the current instruction newly generated at the prediction time is consistent with the future instruction.

6. A three-phase current compensation method according to claim 5, characterized in that: The first current compensation current, the second current compensation current and the future compensation current all include current magnitude, current direction and phase.

7. A three-phase current compensation system, used to execute a three-phase current compensation method according to any one of claims 1 to 6, configured with a central controller and a plurality of SVG units communicating with the central controller, wherein: The central controller is used to distribute compensation instructions to multiple SVG units to achieve collaborative operation among the multiple SVG units to complete the compensation of three-phase unbalanced current. The compensation system includes: An unbalance quantification module is used to collect the current three-phase current at the location of each SVG unit, and when it is detected that the current three-phase current is unbalanced, calculate the current unbalance amount to be compensated; An unbalance prediction module, used for inputting the current three-phase current into a pre-trained prediction model to perform unbalance prediction at a prediction time, and outputting a prediction result, wherein the prediction result is a future unbalance amount to be compensated; A compensation instruction generation module, which is used for generating a compensation current instruction of each SVG unit based on the operating parameters of each SVG unit and the central controller according to the future unbalance amount to be compensated and the current unbalance amount, wherein the compensation current instruction includes a current instruction and a future instruction; An instant compensation execution module, configured to cause the SVG unit to generate a first current compensation current according to the current instruction to offset a current unbalanced amount of the current three-phase current; The future compensation adjustment module is used to generate a future compensation current and wait for the SVG unit according to the future instruction, and when the predicted time is reached, determine whether the current instruction newly generated at the predicted time is consistent with the future instruction. If they are consistent, compensation is performed according to the future compensation current. If they are not consistent, the SVG unit regenerates a second current compensation current for compensation according to the current instruction newly generated at the predicted time.

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