DVR-driven photovoltaic energy storage control system and control method

Abstract

The invention provides a DVR-driven photovoltaic energy storage control system and control method, and relates to the technical field of photovoltaic energy storage, and the system comprises a judgment plug-in introduction module which is used for introducing multi-stage classified judgment plug-ins and is disposed in a DVR in an embedded manner; the access module is used for connecting the DVR to the photovoltaic energy storage power grid in series according to the voltage disturbance condition; the voltage compensation decision module is used for executing electric data monitoring of each voltage regulation position, assisting the accessed DVR, executing hierarchical cascade judgment and a voltage compensation decision based on a double closed-loop fractional order, and determining a compensation voltage; and the voltage recovery management module is used for executing dynamic voltage recovery management of the photovoltaic energy storage power grid by superposing the voltage of the voltage regulation position and the compensation voltage. According to the invention, the technical problem that the conventional proportional-integral controller cannot achieve an ideal control effect because the DVR control design in the prior art basically adopts the proportional-integral controller and the DVR is a nonlinear system is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic energy storage, and in particular to a DVR-driven photovoltaic energy storage control system and a control method. Background Art

[0002] Voltage sags are a frequent problem in dynamic power quality in power systems. These faults can trip operating AC contactors and even damage critical voltage-sensitive equipment. Installing a dynamic voltage restorer (DVR) on critical voltage-sensitive equipment can cost-effectively address the impact of voltage sags. The control strategy is the core issue for DVRs, determining their voltage compensation performance. DVRs effectively manage voltage sags on the equipment side. Currently, DVR control designs typically utilize proportional-integral (PI) controllers. However, DVRs are nonlinear systems, and traditional PI controllers do not achieve ideal control results. Summary of the Invention

[0003] This application provides a DVR-driven photovoltaic energy storage control system and control method, aiming to solve the technical problem that the DVR control design in the prior art basically adopts a proportional-integral controller, but the DVR is a nonlinear system and the traditional proportional-integral controller cannot achieve the ideal control effect.

[0004] The first aspect disclosed in the present application provides a DVR-driven photovoltaic energy storage control system, the system comprising: a judgment plug-in introduction module for introducing a multi-level classification judgment plug-in, embedded in a DVR; an access module for connecting the DVR in series to a photovoltaic energy storage grid based on voltage disturbance conditions, wherein access modes include centralized access, single-point access, and extended channel access; a voltage compensation decision module for performing electrical data monitoring at each voltage regulation location on the photovoltaic energy storage grid, assisting the connected DVR in performing hierarchical cascade judgment and double-closed-loop fractional-order voltage compensation decisions to determine the compensation voltage; and a voltage recovery management module for performing dynamic voltage recovery management of the photovoltaic energy storage grid by superimposing the voltage at the voltage regulation location with the compensation voltage.

[0005] A second aspect disclosed in the present application provides a DVR-driven photovoltaic energy storage control method, which is implemented using the aforementioned DVR-driven photovoltaic energy storage control system. The method includes: introducing a multi-level classification judgment plug-in and deploying it in an embedded manner in a DVR; connecting the DVR in series to a photovoltaic energy storage grid based on voltage disturbance conditions, wherein the access methods include centralized access, single-point access, and extended channel access; performing electrical data monitoring at each voltage regulation location on the photovoltaic energy storage grid, and assisting the connected DVR in performing hierarchical cascade judgment and voltage compensation decision-making based on a double closed-loop fractional order to determine the compensation voltage; and performing dynamic voltage recovery management of the photovoltaic energy storage grid by superimposing the voltage at the voltage regulation location and the compensation voltage.

[0006] One or more technical solutions provided in this application have at least the following beneficial effects:

[0007] By introducing a multi-level classification judgment plug-in and embedding it in the DVR, the power grid can automatically execute different response strategies according to different types of voltage disturbances. This intelligent decision-making enables the photovoltaic energy storage grid to identify abnormal fluctuations in the grid operation in real time and make accurate judgments, thereby improving the system's resilience and recovery speed. Through flexible access methods, including centralized access, single-point access, and extended channel access, it can effectively adapt to photovoltaic energy storage grids of different sizes and types. Whether it is a small distributed photovoltaic system or a large-scale photovoltaic power station, it can be combined with the DVR through optimized access methods to achieve intelligent management of voltage regulation and compensation, which can effectively improve the efficiency of photovoltaic power generation and ensure the stable output of the photovoltaic system and the balance of the grid. It can judge the type of voltage disturbance in the grid through hierarchical cascade judgment and Using a dual-loop fractional-order control decision maker for dynamic voltage compensation decisions not only allows for real-time adjustment of the compensation voltage but also enables fine-tuning based on the actual grid state, ensuring that grid voltage recovery meets precise and stable requirements. This efficient intelligent control enables the grid to quickly recover stability when subjected to load fluctuations or other external disturbances, improving the smart grid's adaptability in complex environments. By superimposing the voltage at the voltage regulation location with the compensation voltage in real time, dynamic voltage recovery management is implemented. This dynamic adjustment ensures that the grid voltage remains within a stable range even when solar power generation fluctuates significantly, preventing voltage anomalies or grid instability caused by fluctuations in photovoltaic power generation. Through this management strategy, photovoltaic energy storage grids can better adapt to grid changes and maintain efficient and stable power output. Overall, in smart grids, DVRs, as key voltage regulation devices, automatically adjust grid voltage and respond quickly through intelligent judgment plug-ins and control algorithms. Through this refined voltage management, photovoltaic energy storage grids not only provide high-quality power output but also ensure voltage stability during grid load fluctuations, enhancing the grid-connected capabilities of photovoltaic power generation.

[0008] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 A schematic structural diagram of a DVR-driven photovoltaic energy storage control system provided in an embodiment of the present application.

[0010] Figure 2 A schematic flow chart of a DVR-driven photovoltaic energy storage control method provided in an embodiment of the present application.

[0011] Description of the reference numerals: plug-in introduction judgment module 10, access module 20, voltage compensation decision module 30, voltage recovery management module 40. DETAILED DESCRIPTION

[0012] The embodiments of the present application provide a DVR-driven photovoltaic energy storage control system and control method, thereby solving the technical problem that the DVR control design in the prior art basically adopts a proportional-integral controller, but the DVR is a nonlinear system and the traditional proportional-integral controller cannot achieve the ideal control effect.

[0013] After introducing the basic principles of this application, various non-limiting embodiments of this application will be specifically described below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described here are only used to explain this application and are not used to limit this application.

[0014] Example 1, as Figure 1 As shown, an embodiment of the present application provides a DVR-driven photovoltaic energy storage control system, the system comprising:

[0015] The judgment plug-in introduction module 10 is used to introduce a multi-level classification judgment plug-in and is embedded in the DVR.

[0016] The access module 20 is used to connect the DVR in series to the photovoltaic energy storage grid according to the voltage disturbance condition, wherein the access modes include centralized access, single-point access and extended channel access.

[0017] The voltage compensation decision module 30 is used to perform electrical data monitoring of each voltage regulation position on the photovoltaic energy storage grid, assist the connected DVR, perform hierarchical cascade judgment and voltage compensation decision based on double closed-loop fractional order, and determine the compensation voltage.

[0018] The voltage recovery management module 40 is used to perform dynamic voltage recovery management of the photovoltaic energy storage grid by superimposing the voltage at the voltage regulation position and the compensation voltage.

[0019] Furthermore, the judgment plug-in introduction module is used to perform the following operation steps:

[0020] A voltage swell is regarded as a reverse direction, and a voltage sag is regarded as a forward direction. The first judgment layer is determined by the binary classification of forward and reverse directions, wherein a voltage interruption belongs to the voltage sag.

[0021] The second judgment layer is determined by binary classification into steady state and non-steady state.

[0022] The first judgment layer and the second judgment layer are cascaded to determine the judgment plug-in.

[0023] Furthermore, the access module is used to perform the following operation steps:

[0024] The photovoltaic energy storage grid is traversed to determine the distributed voltage regulation position.

[0025] The distributed voltage regulation locations are clustered based on the same voltage disturbance scenario to determine multiple groups of voltage regulation locations, wherein each group includes at least one voltage regulation location.

[0026] The DVRs are deployed in series with respect to the multiple groups of voltage regulation positions.

[0027] Furthermore, the access module is used to perform the following operation steps:

[0028] If the group contains a voltage regulating location, use single-point access to connect the DVR in series.

[0029] If the group contains at least two voltage regulating positions, a centralized access method is adopted, and any voltage regulating position is connected in series to the DVR, and the same frequency voltage regulating control is provided to the remaining voltage regulating positions based on the coupling transformer.

[0030] Furthermore, the access module is used to perform the following operation steps:

[0031] Determine the expansion channel based on the capacity of the DVR.

[0032] Adopt the extended channel access method to implement the inter-group channel deployment of multiple groups of voltage regulation positions.

[0033] Furthermore, the voltage compensation decision module is configured to perform the following steps:

[0034] Obtain the electrical data of the voltage regulating location and import it into the corresponding DVR.

[0035] The built-in judgment component performs cascade judgment of the first judgment layer and the second judgment layer to determine the pressure change vector.

[0036] According to the voltage change vector, a double closed-loop fractional-order decision maker is triggered to make a voltage compensation decision, determine the compensation voltage, and perform regulation under voltage compensation superposition.

[0037] Furthermore, the voltage compensation decision module is configured to perform the following steps:

[0038] If it is a steady state, the compensation voltage is the voltage value and the compensation time.

[0039] If it is an unstable state, the compensation voltage is a voltage value fluctuation curve under the compensation time.

[0040] Furthermore, the voltage recovery management module is configured to perform the following operation steps:

[0041] The voltage at the voltage regulation position is superimposed on the compensation voltage, dynamic voltage recovery is performed on the voltage regulation position of the photovoltaic energy storage grid, and voltage regulation response electrical data is tracked.

[0042] According to the voltage regulation response electrical data, the judgment plug-in deployed in the DVR is assisted to perform voltage status judgment with a preset slack as a constraint, and perform feedback management of dynamic voltage recovery.

[0043] Through the detailed description of a DVR-driven photovoltaic energy storage control method in the subsequent description of this specification, those skilled in the art can clearly understand a DVR-driven photovoltaic energy storage control system in this embodiment. Since it corresponds to the method disclosed in the embodiment, the description is relatively simple. For relevant details, please refer to the method section.

[0044] Example 2, based on the same inventive concept as a DVR-driven photovoltaic energy storage control system in the above embodiment, Figure 2 As shown, an embodiment of the present application provides a DVR-driven photovoltaic energy storage control method, the method comprising:

[0045] A multi-level classification judgment plug-in is introduced and embedded in the DVR.

[0046] A multi-level classification judgment plug-in is introduced. By analyzing voltage disturbance conditions, it can classify different voltage disturbances and provide a fuzzy guide for subsequent voltage compensation decisions. This fuzzy guide can cope with complex voltage variations in the power grid, especially when dynamic loads or disturbances occur, allowing for more appropriate system adjustments. Embedded deployment in the DVR (Dynamic Voltage Restorer) means that the judgment plug-in is tightly integrated with the DVR as an embedded component, enabling real-time processing of voltage data from the photovoltaic energy storage grid. The advantage of embedded deployment is that it reduces external dependencies and improves the system's real-time performance and reliability. In practice, the judgment plug-in identifies voltage disturbances through a multi-level classification approach. Common classification criteria include voltage swell, voltage sag, steady state, and non-steady state. These classifications help the system quickly identify different types of voltage disturbances in the power grid and provide guidance for subsequent voltage compensation decisions.

[0047] According to the voltage disturbance condition, the DVR is connected in series to the photovoltaic energy storage grid, wherein the access modes include centralized access, single-point access and extended channel access.

[0048] The DVR is connected in series to the photovoltaic energy storage grid according to the voltage disturbance condition. The access methods include centralized access, single-point access and extended channel access. Among them, centralized access means that the DVR is connected as a control unit to a specific location of the photovoltaic energy storage grid, usually the main power supply or load area of the grid. Under this access method, the DVR determines whether to perform voltage compensation by monitoring the voltage disturbance in the photovoltaic energy storage grid. The centralized DVR can monitor and compensate for voltage disturbances in a larger range. It is suitable for areas where voltage disturbances are more concentrated and there is no need to manage multiple independent areas at the same time. Single-point access means that the DVR is connected to a specific point in the photovoltaic energy storage grid. This point is usually affected by a larger voltage. In areas affected by disturbances or load changes, the DVR monitors voltage changes at that point and activates the voltage compensation mechanism when voltage fluctuations are detected. When there are relatively obvious local voltage fluctuations in the power grid, the single-point access method can provide targeted voltage recovery and compensation. Extended channel access refers to connecting the DVR to multiple locations or multiple areas through additional channels. This access method enables the DVR to process voltage disturbances in different areas of the photovoltaic energy storage grid through multiple parallel channels. In this mode, the DVR collaborates through multiple access points and channels to achieve accurate voltage compensation and recovery. This method is suitable for situations that require more complex voltage control and compensation, such as multiple regulation points or multiple areas with unstable voltage.

[0049] The photovoltaic energy storage grid is subjected to electrical data monitoring at each voltage regulation position, and the connected DVR is assisted to perform hierarchical cascade determination and voltage compensation decision-making based on double closed-loop fractional order to determine the compensation voltage.

[0050] Real-time electrical data monitoring is performed on all voltage regulating locations in the photovoltaic energy storage grid. The voltage regulating location is a key node for voltage regulation in the grid, usually a device close to the load or power supply. Through sensors and monitoring equipment, the voltage, current and other electrical data of each voltage regulating location in the grid are obtained in real time, including voltage fluctuations, frequency changes, load changes, etc., to provide information support for the next step of voltage compensation decision.

[0051] Hierarchical cascade judgment is a multi-level decision-making method that can make judgments in sequence based on different voltage disturbance types (such as voltage sag, voltage swell, steady state and unsteady state) and ultimately determine the control strategy of the power grid. In this judgment, the first level of judgment is first made based on the voltage data (for example, identifying voltage swell or sag), followed by the second level of judgment (such as steady state and unsteady state). This multi-level classification judgment helps to take appropriate compensation measures according to different voltage conditions.

[0052] Dual closed-loop fractional-order control is an advanced control strategy that can effectively cope with voltage fluctuations and provide precise compensation. Dual closed-loop control refers to the use of two closed-loop control systems in voltage compensation decisions. One control loop is used to accurately track the voltage, and the other loop adjusts the response speed of the compensation. Fractional-order control introduces fractional-order calculus, which can provide more precise control effects. It is especially effective when the power grid is subject to complex disturbances. This control method can dynamically adjust the compensation voltage when the power grid voltage fluctuates, maintaining a high voltage stability.

[0053] Based on hierarchical cascade judgment and dual closed-loop fractional-order control, the compensation voltage is finally determined. The compensation voltage is the reverse compensation of the voltage disturbance. The value of the compensation voltage is determined through the voltage compensation function of the DVR, so that the power grid is restored to the predetermined voltage range.

[0054] By superimposing the voltage at the voltage regulation position and the compensation voltage, dynamic voltage recovery management of the photovoltaic energy storage grid is performed.

[0055] The actual voltage at the voltage regulator location is superimposed with the calculated compensation voltage to achieve voltage recovery. Specifically, the voltage at the voltage regulator location reflects the current grid voltage level, while the compensation voltage is the voltage to be restored after the grid disturbance. By superimposing the two, voltage recovery is achieved, bringing the grid voltage back to its normal operating range after the disturbance. The key to dynamic management lies in real-time adjustment of the compensation scheme based on changes in voltage disturbances and feedback control of the recovery process to ensure the continued stable operation of the grid.

[0056] Furthermore, a multi-level classification judgment plug-in is introduced, including:

[0057] A voltage swell is considered as a reverse direction, a voltage sag is considered as a forward direction, and a first judgment layer is determined by binary classification of forward and reverse directions, wherein a voltage interruption belongs to the voltage sag; a second judgment layer is determined by binary classification of steady state and unstable state; the first judgment layer and the second judgment layer are cascaded to determine the judgment plug-in.

[0058] A voltage swell is a phenomenon in which the voltage rises rapidly in a short period of time and exceeds the normal operating voltage, usually lasting from a few milliseconds to a few seconds. It is usually caused by a sudden drop in load, a sudden disconnection of power equipment, a tripped relay, etc. A voltage swell is defined as a positive disturbance. A voltage sag is a phenomenon in which the voltage drops below the normal operating voltage in a short period of time, usually lasting from a few milliseconds to a few seconds. It is usually caused by a sudden increase in load, equipment failure, a short circuit, etc. A voltage sag is defined as a negative disturbance. Through this positive and negative binary classification, the first judgment layer is determined, which can identify the type of disturbance in the power grid so that appropriate compensation measures can be taken later. Among them, a voltage interruption refers to the complete loss of voltage in the power grid, or the voltage suddenly jumps to zero. In this step, the voltage interruption is classified as a voltage sag because a voltage interruption usually causes a sharp drop in the voltage of the power grid and requires compensation measures to restore it.

[0059] Steady state refers to voltage fluctuations within a stable range, with relatively gentle changes and no drastic disturbances. This state typically represents voltage changes during normal grid operation, with small and slow fluctuations. Unsteady state refers to voltage fluctuations with large fluctuations, potentially due to short-term load changes or equipment failures. This disturbance significantly impacts the normal operation of the grid and requires real-time adjustments to compensate. Voltage disturbances in the grid are divided into steady state and unsteady state, and a second judgment layer is determined. This judgment layer determines the current voltage state by monitoring voltage fluctuation characteristics, such as the frequency, amplitude, and duration of the changes, and classifies it as steady state or unsteady state.

[0060] The first judgment layer is combined with the second judgment layer, and the results of the first judgment layer and the second judgment layer are cascaded to finally form a complete judgment plug-in. In this way, the disturbance situation in the power grid can be identified more accurately, providing a basis for subsequent voltage compensation decisions.

[0061] Furthermore, connecting the DVR in series to the photovoltaic energy storage grid includes:

[0062] The photovoltaic energy storage grid is traversed to determine distributed voltage regulation locations; for the distributed voltage regulation locations, multiple groups of voltage regulation locations are clustered based on the same voltage disturbance scenario to determine each group, wherein each group contains at least one voltage regulation location; for the multiple groups of voltage regulation locations, the DVRs are deployed in series.

[0063] Photovoltaic energy storage grids are usually composed of multiple regulating devices (such as transformers, inverters and voltage regulators), which can adjust voltage and power to ensure the stability of the grid. Distributed voltage regulation locations refer to multiple decentralized and non-centralized voltage regulation points in the grid. In photovoltaic energy storage grids, the distribution of these voltage regulation locations is usually determined by factors such as load demand, energy storage device configuration and grid topology. The traversal process means scanning all potential voltage regulation locations in the entire photovoltaic energy storage grid, identifying the voltage control device at each location and recording it, thereby determining the distributed voltage regulation locations. These distributed voltage regulation locations can monitor voltage changes in the grid in real time and adjust them as needed.

[0064] Voltage disturbance scenarios refer to different types of voltage changes in the power grid, including voltage swells, sags, steady states, and unstable states. Different disturbance scenarios may affect different voltage regulating locations, so they need to be grouped according to the actual disturbance conditions. Clustering is to group the voltage regulating locations with similar voltage disturbance characteristics in the power grid into a group. In this process, a clustering algorithm is used to cluster the voltage regulating locations with similar voltage responses into the same group based on the size, duration, frequency, and other characteristics of the voltage disturbance. For example, if multiple voltage regulating locations respond similarly to a certain voltage disturbance, such as exhibiting similar recovery patterns when the voltage swells, they are classified into the same group. Through clustering, multiple groups of voltage regulating locations are determined. Each group of voltage regulating locations contains at least one voltage regulating location, and all voltage regulating locations are effectively assigned to groups based on the similarity of their disturbance responses.

[0065] Connecting the DVR in series with multiple groups of voltage regulators means the DVR can simultaneously support multiple groups of voltage regulators. Each group of voltage regulators uses the DVR's regulation to restore its voltage level, ensuring overall grid voltage stability. In this step, the DVRs are connected based on the distribution of the multiple groups of voltage regulators and the voltage disturbance. For each group of voltage regulators, its voltage fluctuation characteristics and compensation requirements are evaluated, and then the DVRs are effectively deployed in each group. For example, if a voltage regulator in a group experiences a large voltage disturbance, the DVR needs to provide stronger voltage compensation. Conversely, if the voltage regulator's response to the voltage disturbance is small, the DVR intervention can be relatively minor.

[0066] Furthermore, if the group contains one voltage regulating position, a single-point access method is used to connect the DVR in series; if the group contains at least two voltage regulating positions, a centralized access method is used to connect the DVR in series at any voltage regulating position, and the same-frequency voltage regulation control is provided for the remaining voltage regulating positions based on the coupling transformer.

[0067] When a group in the clustering results contains only one voltage regulating location, a single-point access method is adopted. Single-point access means directly connecting the DVR in series to a single voltage regulating location in the power grid. This method is suitable for scenarios where only one voltage regulating location requires voltage compensation, avoiding the need to adjust multiple voltage regulating locations in the entire power grid. In this case, the DVR's task is to dynamically compensate the voltage at that voltage regulating location, monitor the voltage changes at that location in real time, and perform rapid voltage recovery through the DVR.

[0068] When a clustered group contains at least two VTRs, centralized access is used. Centralized access involves connecting a DVR in series to any VTR in the group. Voltage regulation is then performed on the remaining VTRs using a coupling transformer. The coupling transformer transmits the voltage adjustment signal from the primary VTR to the other VTRs, ensuring consistent voltage regulation across all VTRs. This transformer provides a common voltage regulation channel, ensuring consistent voltage compensation across the entire system. This ensures that all affected VTRs receive the corresponding compensation voltage based on the primary VTR's voltage regulation requirements. In this scenario, DVRs do not need to be individually connected to each VTR. Instead, voltage compensation is achieved across multiple VTRs through centralized control. This access method is suitable for areas with relatively concentrated loads, similar voltage disturbances, and consistent regulation requirements. For example, if the voltage fluctuations at multiple VTRs are simultaneously affected by the same disturbance, centralized access can adjust the voltage at one location to affect the entire area. By eliminating the need for individual DVRs for each VTR, centralized access reduces system deployment cost and complexity.

[0069] Furthermore, an expansion channel is determined based on the capacity of the DVR; and an expansion channel access method is adopted to implement inter-group channel deployment of multiple groups of voltage regulation positions.

[0070] The capacity of a DVR refers to the voltage and power range it can handle. A larger DVR capacity means it can handle more loads and more complex voltage regulation requirements. When the DVR capacity is larger, it can support multiple expansion channels, each of which can independently perform voltage regulation. The expansion channel design enables the DVR to flexibly handle the voltage compensation requirements of multiple voltage regulation positions, rather than being limited to one channel.

[0071] Specifically, if the DVR has a small capacity, it typically only supports a single voltage regulation channel, and voltage regulation can only be performed within that channel. Larger DVRs can support multiple expansion channels, which can operate independently to regulate voltage in different areas. Multiple expansion channels allow the DVR to independently adjust multiple voltage regulation locations, eliminating the need for each location to be regulated through the same channel. This improves the flexibility and accuracy of voltage regulation. Some industrial-grade DVRs support a modular design, allowing for the addition of additional control modules to support the independent adjustment of multiple voltage compensation locations. Each module can independently control a voltage regulation location, ensuring accurate and timely voltage compensation at each voltage regulation point.

[0072] Extended channel access refers to connecting the DVR to different voltage regulation positions of the power grid through multiple channels, so that each channel can independently perform voltage compensation. Each channel controls a group of voltage regulation positions, so the voltage of each area in the power grid can be adjusted more finely. For each group of voltage regulation positions, access is deployed through an extended channel. Each channel will independently adjust the voltage of the voltage regulation positions within its group to ensure that each area can obtain independent voltage compensation. In this way, voltage regulation can be independently performed according to the voltage changes of each group of voltage regulation positions, improving the response speed and accuracy of the system.

[0073] Furthermore, the execution level cascade determination and voltage compensation decision based on double closed-loop fractional order include:

[0074] Obtain electrical data at the voltage regulation location and import it into the corresponding DVR; perform cascade judgment of the first judgment layer and the second judgment layer according to the built-in judgment component to determine the voltage change vector; trigger a dual closed-loop fractional-order decision maker based on the voltage change vector to make a voltage compensation decision, determine the compensation voltage, and perform regulation under voltage compensation superposition.

[0075] Electrical data such as voltage and current at each voltage regulating location fluctuates as the grid status changes. Using sensors or measuring devices installed at each voltage regulating location, such as voltmeters, ammeters, or power meters, the DVR acquires real-time data such as voltage, frequency, and power. This data reflects the actual operating status of the grid and the voltage fluctuations at each voltage regulating location. The acquired data is imported into the DVR, which uses this data to determine the current voltage status of the grid and implement voltage compensation strategies.

[0076] The first judgment layer distinguishes different voltage fluctuation patterns, including voltage swells or dips, by determining the type of voltage disturbance. The second judgment layer further determines whether the disturbance is in a steady-state or unsteady-state state. The voltage change vector is the voltage variation that needs to be adjusted when performing voltage compensation. Through cascade judgment, the direction and magnitude of the compensation voltage can be determined. Specifically, if the voltage sags and is determined to be steady-state, the compensation voltage is a positive and stable voltage, that is, the compensation voltage is directly superimposed on the current voltage to restore the grid to the standard voltage. If the voltage sags and is determined to be unsteady-state, the compensation voltage is a dynamic fluctuation, that is, the compensation voltage is a dynamic response to grid voltage fluctuations, with the purpose of responding to voltage fluctuations and minimizing the impact of disturbances on the grid.

[0077] The dual-closed-loop fractional-order decision maker is a system consisting of two control loops. One loop controls the accuracy of voltage compensation, and the other loop controls the speed of compensation response. Through the dual-closed-loop design, it can quickly respond to voltage fluctuations while ensuring voltage accuracy. Fractional-order control is a more sophisticated control method than traditional integer-order control. It uses fractional-order calculus to improve the response speed and control accuracy to voltage disturbances by carefully adjusting the control system parameters. It is used to deal with nonlinear fluctuations and transient changes in the power grid.

[0078] The dual-closed-loop fractional-order decision maker determines the compensation voltage required to restore grid stability based on the magnitude and direction of the voltage change vector. The compensation voltage is calculated in real time to ensure rapid and accurate voltage compensation. Once the compensation voltage is determined, the DVR superimposes it with the current grid voltage to restore the grid to a stable state. This process is dynamic, and the compensation voltage is continuously adjusted as the grid changes in real time. Dual closed-loop control allows for precise control of the speed and stability of voltage recovery during the voltage compensation process, ensuring the expected compensation voltage results.

[0079] Furthermore, if it is a steady state, the compensation voltage is the voltage value and the compensation time; if it is an unsteady state, the compensation voltage is the voltage value fluctuation curve under the compensation time.

[0080] Steady state refers to a state in which the voltage fluctuations in the power grid are stable, the variation range is small, and the voltage changes within the system tend to be stable, that is, the voltage is maintained within the normal working range. In steady state, the voltage will not fluctuate significantly, and the power grid operates in a relatively stable working state.

[0081] Under steady-state conditions, the compensation voltage is composed of two main factors: voltage value and compensation time. The voltage value refers to the target value of the voltage at a certain voltage regulating position in the power grid under steady-state conditions. This value is the ideal voltage level after system design and adjustment. This voltage value is the stable voltage value after the power grid resumes normal operation. The compensation time refers to the recovery time of the power grid after a voltage disturbance occurs. The compensation time describes the time required for the voltage compensation process by adjusting devices such as DVRs. Usually, this time is a time window to ensure that the voltage is stable and returns to the set value. Specifically, when the power grid is in steady-state, the DVR ensures that the power grid voltage remains at a predetermined stable level by accurately adjusting the compensation voltage. At this time, the voltage value and the compensation time work together to determine the size and duration of the compensation voltage. Usually, the compensation voltage under steady-state conditions is designed to keep the power grid voltage constant at the target value. Frequent adjustment or dynamic correction is not required because the power grid is already stable and the disturbance is relatively minor.

[0082] An unstable state refers to a situation where the voltage in the power grid fluctuates significantly. Usually, such fluctuations are caused by transient disturbances or external factors, such as load fluctuations, equipment failures, or power fluctuations. In an unstable state, the voltage changes irregularly and more complex compensation measures are required to restore stability.

[0083] In an unstable state, the compensation voltage is a voltage fluctuation curve that changes with the compensation time. This fluctuation curve describes the dynamic characteristics of the voltage value changing with time during the voltage recovery process. At this time, the compensation voltage adopts a dynamic adjustment strategy and adjusts according to the real-time changes in the grid voltage to ensure that the voltage fluctuation is controlled within a reasonable range as much as possible. The compensation voltage will be continuously corrected according to the voltage fluctuation of the grid during the recovery process. Specifically, when the grid is in an unstable state, the DVR calculates the fluctuation curve of the compensation voltage based on the real-time data of the grid voltage fluctuation. The adjustment process of the compensation voltage includes: dynamically adjusting the compensation voltage according to the nature and duration of the disturbance, and adjusting the voltage value in real time to restore the stability of the grid as soon as possible. This strategy involves continuous monitoring of the voltage changes at each voltage regulation position in the grid, and adjusting the amplitude of the compensation voltage based on the amplitude and frequency of the voltage change. Over time, the compensation voltage gradually tends to stabilize and eventually returns to a steady state.

[0084] Furthermore, after executing the dynamic voltage recovery management of the photovoltaic energy storage grid, it includes:

[0085] The voltage at the voltage regulation position is superimposed on the compensation voltage, dynamic voltage recovery is performed on the voltage regulation position of the photovoltaic energy storage grid, and voltage regulation response electrical data is tracked; based on the voltage regulation response electrical data, a judgment plug-in deployed in the DVR is assisted to perform voltage status judgment with a preset slack as a constraint, and feedback management of dynamic voltage recovery is performed.

[0086] The DVR adjusts the voltage at each voltage regulating location, adding the actual voltage to the calculated compensation voltage to form a new voltage value. This new voltage value is close to the target stable voltage, helping the power grid to quickly return to normal. Using the superimposed voltage values, the DVR performs dynamic voltage recovery on the voltage regulating locations, which means that the grid voltage is gradually restored to the ideal stable voltage level through real-time compensation. During the voltage recovery process, the voltage regulation response electrical data of each voltage regulating location is continuously tracked, that is, the actual changes in the voltage at the voltage regulating location. By monitoring this data in real time, the effectiveness of the compensation measures can be understood and the compensation strategy can be adjusted at any time. For example, if the voltage recovery at certain voltage regulating locations is slow or fluctuates greatly, the voltage regulation response electrical data can be analyzed to identify problems in the recovery process and make compensation adjustments in a timely manner.

[0087] The judgment plug-in deployed within the DVR plays a key role in the voltage restoration process. It analyzes the voltage regulation response data to determine the voltage status during the recovery process. The preset slack refers to the system's allowable voltage deviation range, allowing voltage fluctuations within a certain range. As long as the voltage value remains within this normal range, the grid is considered stable. During the voltage recovery process, the slack helps determine whether further adjustments are needed. If the restored voltage exceeds the normal range, the feedback mechanism is triggered for adjustment.

[0088] The judgment plug-in evaluates whether the voltage has returned to a stable range based on real-time tracking of voltage regulation response electrical data. By using a preset slack, the judgment plug-in can determine whether the current voltage is within an acceptable deviation range. If the voltage change after voltage regulation is still within the preset slack, the grid state can be considered to have returned to stability; if the voltage exceeds this range, further feedback decisions need to be triggered.

[0089] If the regulated voltage still exceeds the normal range, the feedback decision mechanism is activated, and the feedback compensation voltage is recalculated based on the voltage regulation response electrical data and superimposed on the previous compensation voltage. This means that the voltage compensation process will continue to ensure that the power grid returns to the predetermined stable voltage state. Through the feedback mechanism, the adjustment of the compensation voltage can be continuously optimized according to the real-time voltage situation. This feedback process is dynamic and is continuously adjusted until the voltage of the power grid is stable.

[0090] In summary, the DVR-driven photovoltaic energy storage control method provided in the embodiments of the present application has the following technical effects:

[0091] By introducing a multi-level classification judgment plug-in and embedding it in the DVR, the power grid can automatically execute different response strategies according to different types of voltage disturbances. This intelligent decision-making enables the photovoltaic energy storage grid to identify abnormal fluctuations in the grid operation in real time and make accurate judgments, thereby improving the system's resilience and recovery speed. Through flexible access methods, including centralized access, single-point access, and extended channel access, it can effectively adapt to photovoltaic energy storage grids of different sizes and types. Whether it is a small distributed photovoltaic system or a large-scale photovoltaic power station, it can be combined with the DVR through optimized access methods to achieve intelligent management of voltage regulation and compensation, which can effectively improve the efficiency of photovoltaic power generation and ensure the stable output of the photovoltaic system and the balance of the grid. It can judge the type of voltage disturbance in the grid through hierarchical cascade judgment and Using a dual-loop fractional-order control decision maker for dynamic voltage compensation decisions not only allows for real-time adjustment of the compensation voltage but also enables fine-tuning based on the actual grid state, ensuring that grid voltage recovery meets precise and stable requirements. This efficient intelligent control enables the grid to quickly recover stability when subjected to load fluctuations or other external disturbances, improving the smart grid's adaptability in complex environments. By superimposing the voltage at the voltage regulation location with the compensation voltage in real time, dynamic voltage recovery management is implemented. This dynamic adjustment ensures that the grid voltage remains within a stable range even when solar power generation fluctuates significantly, preventing voltage anomalies or grid instability caused by fluctuations in photovoltaic power generation. Through this management strategy, photovoltaic energy storage grids can better adapt to grid changes and maintain efficient and stable power output. Overall, in smart grids, DVRs, as key voltage regulation devices, automatically adjust grid voltage and respond quickly through intelligent judgment plug-ins and control algorithms. Through this refined voltage management, photovoltaic energy storage grids not only provide high-quality power output but also ensure voltage stability during grid load fluctuations, enhancing the grid-connected capabilities of photovoltaic power generation.

[0092] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present application. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A DVR-driven photovoltaic energy storage control system, characterized in that: The system comprises: Judgment plug-in introduction module, used to introduce multi-level classification judgment plug-in, embedded deployment in DVR; An access module is used to connect the DVR in series to the photovoltaic energy storage grid according to the voltage disturbance condition, wherein the access mode includes centralized access, single-point access and extended channel access; A voltage compensation decision module is used to monitor the electrical data of each voltage regulation location of the photovoltaic energy storage grid, assist the connected DVR, perform hierarchical cascade judgment and double closed-loop fractional-order voltage compensation decision-making, and determine the compensation voltage; The voltage recovery management module is used to perform dynamic voltage recovery management of the photovoltaic energy storage grid by superimposing the voltage at the voltage regulation position and the compensation voltage.

2. A DVR-driven photovoltaic energy storage control system according to claim 1, characterized in that: The judgment plug-in introduction module is used to perform the following steps: The voltage swell is considered as the reverse direction, and the voltage sag is considered as the forward direction. The first judgment layer is determined by the binary classification of forward and reverse directions, wherein the voltage interruption belongs to the voltage sag; The second judgment layer is determined by binary classification of steady state and non-steady state; The first judgment layer and the second judgment layer are cascaded to determine the judgment plug-in.

3. A DVR-driven photovoltaic energy storage control system according to claim 1, characterized in that: The access module is used to perform the following operation steps: Traversing the photovoltaic energy storage grid to determine the distributed voltage regulation location; Clustering the distributed voltage regulation locations based on the same voltage disturbance scenario to determine multiple groups of voltage regulation locations, wherein each group includes at least one voltage regulation location; The DVRs are deployed in series with respect to the multiple groups of voltage regulation positions.

4. A DVR-driven photovoltaic energy storage control system according to claim 3, characterized in that: The access module is used to perform the following operation steps: If the group contains a voltage regulating location, use single-point access to connect the DVR in series; If the group contains at least two voltage regulating positions, a centralized access method is adopted, and any voltage regulating position is connected in series to the DVR, and the same frequency voltage regulating control is provided to the remaining voltage regulating positions based on the coupling transformer.

5. A DVR-driven photovoltaic energy storage control system according to claim 4, characterized in that: The access module is used to perform the following operation steps: Determine the expansion channel based on the capacity of the DVR; Adopt the extended channel access method to implement the inter-group channel deployment of multiple groups of voltage regulation positions.

6. A DVR-driven photovoltaic energy storage control system according to claim 1, characterized in that: The voltage compensation decision module is used to perform the following operation steps: Obtain the electrical data of the voltage regulating location and import it into the corresponding DVR; Execute cascade judgment of the first judgment layer and the second judgment layer according to the built-in judgment component to determine the pressure change vector; According to the voltage change vector, a double closed-loop fractional-order decision maker is triggered to make a voltage compensation decision, determine the compensation voltage, and perform regulation under voltage compensation superposition.

7. A DVR-driven photovoltaic energy storage control system according to claim 6, characterized in that: The voltage compensation decision module is used to perform the following operation steps: If it is a steady state, the compensation voltage is the voltage value and the compensation time; If it is an unstable state, the compensation voltage is a voltage value fluctuation curve under the compensation time.

8. The DVR-driven photovoltaic energy storage control system according to claim 1, characterized in that: The voltage recovery management module is used to perform the following operation steps: superimposing the voltage at the voltage regulation position and the compensation voltage, performing dynamic voltage recovery on the voltage regulation position of the photovoltaic energy storage grid, and tracking voltage regulation response electrical data; According to the voltage regulation response electrical data, the judgment plug-in deployed in the DVR is assisted to perform voltage status judgment with a preset slack as a constraint, and perform feedback management of dynamic voltage recovery.

9. A DVR-driven photovoltaic energy storage control method, characterized in that: Based on the implementation of a DVR-driven photovoltaic energy storage control system according to any one of claims 1 to 8, the method includes: Introducing a multi-level classification judgment plug-in, embedded and deployed in the DVR; According to the voltage disturbance condition, the DVR is connected in series to the photovoltaic energy storage grid, wherein the access mode includes centralized access, single point access and extended channel access; Performing electrical data monitoring at each voltage regulation location on the photovoltaic energy storage grid, assisting the connected DVR, performing hierarchical cascade determination and voltage compensation decision-making based on double closed-loop fractional order, and determining the compensation voltage; By superimposing the voltage at the voltage regulation position and the compensation voltage, dynamic voltage recovery management of the photovoltaic energy storage grid is performed.

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