Dynamic voltage restorer system based on storage battery-supercapacitor hybrid energy storage

Abstract

The invention discloses a dynamic voltage restorer system based on storage battery-supercapacitor hybrid energy storage, and relates to the technical field of power control, the system comprises a connection interface module, a detection control module, a hybrid energy storage module, a DVR main body module and an energy storage mode management module; according to the method, voltage and current data of a power distribution network and a load are collected in real time, voltage flicker occurrence is accurately judged through a voltage flicker perceptibility coefficient formula, a corresponding energy distribution instruction and a corresponding voltage compensation instruction are generated, and according to the energy distribution instruction, through a hybrid energy storage energy distribution coefficient formula and a charging and discharging power constraint formula, the charging and discharging power of the power distribution network is calculated. The energy output of the storage battery and the supercapacitor is intelligently allocated, it is ensured that needed compensation energy can be rapidly provided during voltage fluctuation, compensation voltage is calculated and output through a DVR compensation voltage calculation formula based on direct-current electric energy, voltage flicker is effectively stabilized, and the electric energy quality of a power distribution network is improved.

Description

Technical Field

[0001] This invention relates to the field of power control technology, specifically to a dynamic voltage restorer system based on a hybrid energy storage system of batteries and supercapacitors. Background Technology

[0002] With the rapid development of modern power systems, the scale and complexity of distribution networks are increasing, and the requirements for power quality are becoming more stringent. Voltage fluctuations and voltage flicker, as common power quality problems, not only affect the normal operation of electrical equipment and reduce production efficiency, but may also threaten the stability and security of the power grid. Especially in the context of large-scale integration of distributed power sources into the distribution network, voltage fluctuations and flicker problems are more prominent due to the intermittent and uncertain output of distributed power sources.

[0003] However, although various voltage restoration and compensation technologies are currently applied in distribution networks, such as uninterruptible power supplies (UPS) and static var compensators (SVCs), these technologies still have certain limitations in practical applications. While UPS can provide short-term power support during power outages, its energy storage capacity is limited and it is difficult to cope with long-term voltage fluctuations. Static var compensators mainly focus on reactive power compensation, and their compensation effect on voltage problems caused by active power fluctuations is limited. In addition, traditional technologies often lack intelligent energy management and energy storage device status monitoring functions, making it difficult to flexibly adjust compensation strategies according to the real-time operating conditions of the power grid, resulting in unsatisfactory voltage restoration efficiency and power quality improvement. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a dynamic voltage restorer system based on a hybrid energy storage system of batteries and supercapacitors. This invention integrates a connection interface module, a detection and control module, a hybrid energy storage module, a DVR main module, and an energy storage mode management module to achieve rapid response and accurate compensation for voltage fluctuations in the distribution network. By collecting voltage and current data of the distribution network and loads in real time, it accurately determines the occurrence of voltage flicker using a voltage flicker perception coefficient formula and generates corresponding energy allocation and voltage compensation commands. Based on the energy allocation commands, it intelligently allocates the energy output of the batteries and supercapacitors using a hybrid energy storage energy allocation coefficient formula and a charge / discharge power constraint formula, ensuring that the required compensation energy can be quickly provided during voltage fluctuations. Based on DC power, it calculates and outputs the compensation voltage using a DVR compensation voltage calculation formula, effectively suppressing voltage flicker and improving the power quality of the distribution network. This design not only improves the efficiency of voltage recovery but also reduces grid losses by optimizing power use, achieving the goal of energy conservation and emission reduction.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a dynamic voltage restorer system based on a hybrid energy storage of a battery and a supercapacitor, the system comprising:

[0006] Connection interface module: It adopts a standardized electrical interface to connect with the busbar, distributed power output terminal and load input terminal of the distribution network, integrates a dedicated signal transmission interface and has a built-in safety protection mechanism;

[0007] Detection and control module: It collects data through voltage and current sensors, calculates the flicker perception coefficient using the voltage flicker perception coefficient formula, analyzes voltage fluctuations when voltage flicker occurs, and generates energy distribution and voltage compensation commands.

[0008] Hybrid energy storage module: Receives energy distribution instructions, calculates the energy output ratio of the battery and supercapacitor through the hybrid energy storage energy distribution coefficient formula and the hybrid energy storage charge and discharge power constraint formula, constrains the output power, and then performs power conversion and power distribution through a bidirectional DC converter to output DC power.

[0009] The main DVR module receives voltage compensation commands and calculates the required compensation voltage based on DC power using the DVR compensation voltage calculation formula. It then converts the DC power into AC power that matches the compensation voltage using a voltage source inverter. Simultaneously, it filters out harmonic components generated during the power conversion process through a filter unit to smooth out voltage flicker.

[0010] Energy storage mode management module: When voltage flicker is eliminated, the hybrid energy storage module switches to hybrid energy storage mode based on the remaining battery capacity and the voltage state of the supercapacitor, according to the energy storage charging and discharging mode switching condition formula.

[0011] Furthermore, the safety protection mechanisms in the connection interface module are as follows: an overcurrent protection mechanism that monitors the current in the transmission line in real time and cuts off the fault circuit when the distribution network experiences current overload due to short circuit or sudden load change; an overvoltage protection mechanism that tracks the distribution network voltage in real time and activates the voltage clamping function to limit the voltage within a safe range when the voltage rises suddenly due to a sudden increase in photovoltaic output or other reasons; and a lightning protection mechanism that absorbs the impact energy generated by lightning strikes when the distribution network is struck by lightning by integrating lightning protection components.

[0012] Furthermore, the detection and control module receives real-time signals from the power distribution network, distributed power sources, and loads through a connection interface module, and collects information on the voltage amplitude, frequency of voltage fluctuations, and voltage phase of the power distribution network through a voltage sensor. It also collects the operating current data of the load through a current sensor and calculates the flicker perception coefficient S(t) using the voltage flicker perception coefficient formula. With the voltage fluctuation range S0 during normal operation of the power distribution network as a benchmark, when S(t) ≥ S0, it is determined that voltage flicker has occurred.

[0013] Furthermore, in the detection and control module, the formula for the voltage flicker sensing coefficient is: Where S(t) is the voltage flicker perception coefficient at time t, U(t) is the distribution network voltage at time t, and U e t is the rated voltage of the distribution network, f(t) is the voltage fluctuation frequency at time t, and k1 and k2 are correction coefficients.

[0014] Furthermore, the detection and control module analyzes the voltage fluctuations that have occurred by combining the short-circuit capacity of the distribution network, the dynamic impedance characteristics of distributed power sources, and the transmission law of flicker in the distribution network, clarifying the frequency and amplitude characteristics of the voltage fluctuations. Based on the analysis results and S(t), it generates energy allocation instructions including voltage fluctuation frequency and amplitude parameters, as well as voltage compensation instructions including flicker perception coefficient and distribution network equivalent impedance parameters.

[0015] Furthermore, the hybrid energy storage module includes a battery, a supercapacitor, a bidirectional DC-DC converter, and an energy storage management unit. After receiving an energy allocation command, it calculates the energy output ratio of the battery and the supercapacitor using the hybrid energy storage energy allocation coefficient formula, clarifies the energy output priority of the battery and the supercapacitor under different voltage fluctuation scenarios, constrains the output power of the battery and the supercapacitor using the hybrid energy storage charge and discharge power constraint formula, and then performs power conversion and power allocation through the bidirectional DC-DC converter to output DC power. At the same time, the energy storage management unit collects the remaining battery power and the supercapacitor terminal voltage data in real time.

[0016] Furthermore, in the hybrid energy storage module, the formula for the hybrid energy storage energy distribution coefficient is: Where α(t) is the energy output percentage of the battery at time t, 1-α(t) is the energy output percentage of the supercapacitor, f(t) is the voltage fluctuation frequency at time t, f0 is the voltage fluctuation frequency threshold, and ΔU(t)=|U(t)-U e | represents the voltage fluctuation amplitude at time t, ΔU0 is the voltage fluctuation amplitude threshold, and k3 and k4 are the response sensitivity coefficients.

[0017] Furthermore, in the hybrid energy storage module, the hybrid energy storage charging and discharging power constraint formula is: Among them, P bat (t), P sc α(t) represents the output power of the battery and the supercapacitor at time t, respectively; α(t) represents the energy output percentage of the battery at time t; 1-α(t) represents the energy output percentage of the supercapacitor; and SOC(t) represents the remaining battery charge at time t. min SOC max U is the safe threshold for the remaining battery power. sc (t) represents the terminal voltage of the supercapacitor at time t, U sc,min U sc,max This refers to the safe voltage threshold for supercapacitors.

[0018] Furthermore, the main DVR module includes a voltage source inverter and a filter unit; the DVR compensation voltage calculation formula is as follows: Among them, U comp (t) represents the compensation voltage that the DVR needs to output at time t, P stor (t)=P bat (t)+P sc Z(t) represents the total output power at time t. grid θ is the equivalent impedance of the distribution network, θ is the phase difference between the compensation voltage and the distribution network voltage, and S(t) is the flicker sensing coefficient.

[0019] Furthermore, in the energy storage mode management module, the formula for switching energy storage charging and discharging modes is as follows: Where Mode(t) represents the hybrid energy storage operating mode at time t.

[0020] Compared with existing technologies, this dynamic voltage restorer system based on battery-supercapacitor hybrid energy storage has the following advantages:

[0021] I. This invention achieves rapid response and precise compensation for voltage fluctuations in the distribution network by integrating a connection interface module, a detection and control module, a hybrid energy storage module, a DVR main module, and an energy storage mode management module. It collects voltage and current data from the distribution network and loads in real time, accurately determines voltage flicker occurrence using a voltage flicker perception coefficient formula, and generates corresponding energy allocation and voltage compensation commands. Based on the energy allocation commands, it intelligently allocates the energy output of the battery and supercapacitor using a hybrid energy storage energy allocation coefficient formula and a charge / discharge power constraint formula, ensuring rapid provision of the required compensation energy during voltage fluctuations. Furthermore, based on DC power, it calculates and outputs the compensation voltage using a DVR compensation voltage calculation formula, effectively suppressing voltage flicker and improving the power quality of the distribution network. This design not only improves voltage recovery efficiency but also reduces grid losses by optimizing power usage, achieving the goals of energy conservation and emission reduction.

[0022] Second, this invention uses a formula for switching energy storage charging and discharging modes to intelligently switch the working mode of the hybrid energy storage module based on the remaining battery power and the voltage state of the supercapacitor. This ensures that the module can maintain optimal operating conditions under different operating conditions. This intelligent management mode not only extends the service life of the energy storage equipment but also improves the overall reliability and stability. At the same time, the safety protection mechanism built into the connection interface module provides safety protection and effectively avoids system damage caused by grid failures or external shocks.

[0023] Other advantages, objectives and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination or study, or may be learned from the practice of the invention. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0025] Figure 1 A flowchart of a dynamic voltage restorer system based on a hybrid battery-supercapacitor energy storage system;

[0026] Figure 2 This is a framework diagram of a dynamic voltage restorer system based on a hybrid energy storage system of batteries and supercapacitors. Detailed Implementation

[0027] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0028] Example 1:

[0029] Connection Interface Module: In the scenario of voltage flicker mitigation in residential communities within a distributed photovoltaic (PV) distribution network, a standardized electrical interface conforming to industry standards is adopted to connect with the distributed PV distribution network bus, the output terminals of multiple PV distributed power sources, and the input terminals of the community load consisting of multiple residential buildings. It integrates a dedicated signal transmission interface adapted to signal transmission requirements; its built-in safety protection mechanisms include, for example... Figure 1As shown, the overcurrent protection mechanism monitors the transmission line current in real time. When the distribution network experiences a sudden load change due to a short circuit or peak residential electricity consumption, causing current overload and exceeding the safe operating range, the faulty circuit is disconnected. The overvoltage protection mechanism tracks the distribution network voltage in real time. When the distribution network voltage exceeds the normal operating range due to a sudden increase in photovoltaic output at midday, the voltage clamping function is activated to limit the voltage within a reasonable and safe range. The lightning protection mechanism absorbs the impact energy when the distribution network is struck by lightning by integrating lightning protection components adapted to the lightning protection needs of the distribution network.

[0030] The detection and control module collects voltage amplitude, voltage fluctuation frequency, and voltage phase information of the distribution network through voltage sensors adapted to the distribution network scenario, and collects operating current data of the residential load through current sensors adapted to the load current range of the residential area; and calculates the flicker perception coefficient using the voltage flicker perception coefficient formula, which is as follows: Where S(t) is the voltage flicker perception coefficient at time t, U(t) is the distribution network voltage at time t, and U e Let S(t) be the rated voltage of the distribution network, f(t) be the voltage fluctuation frequency at time t, and k1 and k2 be correction coefficients. When S(t) ≥ S0, voltage flicker is determined to have occurred. At the same time, the voltage fluctuations that have occurred are analyzed by combining the short-circuit capacity of the distribution network, the dynamic impedance characteristics of photovoltaic distributed power sources, and the transmission law of flicker in the distribution network. The frequency and amplitude characteristics of the voltage fluctuations are clarified. Based on the analysis results and S(t), an energy distribution command containing voltage fluctuation frequency and amplitude parameters, as well as a voltage compensation command containing flicker perception coefficient and distribution network equivalent impedance parameters are generated.

[0031] Hybrid energy storage module: Includes battery, supercapacitor, bidirectional DC-DC converter, and energy storage management unit; after receiving energy allocation instructions, it calculates the energy output ratio of the battery to meet the scenario requirements and the supercapacitor to meet the high-frequency response requirements using the hybrid energy storage energy allocation coefficient formula, clarifying the energy output priority of the battery and supercapacitor under different voltage fluctuation scenarios. The hybrid energy storage energy allocation coefficient formula is as follows: Where α(t) is the energy output percentage of the battery at time t, 1-α(t) is the energy output percentage of the supercapacitor, f(t) is the voltage fluctuation frequency at time t, f0 is the voltage fluctuation frequency threshold, and ΔU(t)=|U(t)-U e | represents the voltage fluctuation amplitude at time t, ΔU0 is the voltage fluctuation amplitude threshold, and k3 and k4 are response sensitivity coefficients. The output power of both is constrained by a hybrid energy storage charging and discharging power constraint formula to ensure that the battery outputs normal power when its remaining charge is within a safe operating range and the supercapacitor's terminal voltage is within a safe operating range. The hybrid energy storage charging and discharging power constraint formula is as follows: Among them, Pbat (t) and P sc (t) are the output powers of the battery and the supercapacitor at time t respectively. α(t) is the proportion of the energy output of the battery at time t, 1 - α(t) is the proportion of the energy output of the supercapacitor, SOC(t) is the remaining charge of the battery at time t, SOC min and SOC max is the safety threshold of the remaining charge of the battery, U sc (t) is the terminal voltage of the supercapacitor at time t, U sc,min and U sc,max is the voltage safety threshold of the supercapacitor; then, through a bidirectional DC converter that adapts to the power demand of the system, electrical energy conversion and power distribution are carried out to output DC electrical energy. At the same time, the energy storage management unit regularly collects data on the remaining charge of the battery and the terminal voltage of the supercapacitor.

[0032] DVR main body module: It includes a voltage source inverter and a filtering unit; after receiving a voltage compensation command, based on the DC electrical energy output by the hybrid energy storage module, the compensation voltage to be output is calculated through the DVR compensation voltage calculation formula. The DVR compensation voltage calculation formula is: Among them, U comp (t) is the compensation voltage that the DVR main body needs to output at time t, P stor (t) = P bat (t) + P sc (t), which is the total output power at time t, Z grid is the equivalent impedance of the distribution network, θ is the phase difference between the compensation voltage and the distribution network voltage, S(t) is the flicker perception coefficient; and through a voltage source inverter that adapts to the compensation demand, the DC electrical energy is converted into AC electrical energy that matches the compensation voltage. At the same time, through a filtering unit that adapts to the harmonic filtering demand, the high-order harmonic components generated during the electrical energy conversion process are filtered out, and the voltage flicker of the distribution network is controlled within a reasonable range that meets the residential electricity demand, suppressing the voltage flicker caused by the fluctuation of photovoltaic output.

[0033] Energy storage mode management module: When the voltage flicker is eliminated, according to the remaining charge of the battery and the terminal voltage state of the supercapacitor, the working mode of the hybrid energy storage is switched through the energy storage charge and discharge mode switching condition formula. The energy storage charge and discharge mode switching condition formula is: Among them, Mode(t) is the working mode of the hybrid energy storage at time t; when S(t) < S0 and SOC(t) < SOC max and U sc (t) < U sc,maxWhen the battery reaches its maximum capacity and the supercapacitor reaches its maximum voltage, the system switches to charging mode, utilizing the excess electricity generated when the photovoltaic output exceeds the residents' load demand at midday to charge both batteries and the supercapacitor, thus avoiding overcharging and damage to the energy storage equipment. When the battery's remaining power reaches its maximum capacity and the supercapacitor's terminal voltage reaches its maximum capacity, the system switches to standby mode, maintaining only basic data monitoring functions and waiting for the next voltage flicker to occur before responding quickly.

[0034] In summary, for voltage flicker mitigation scenarios in residential communities using distributed photovoltaic (PV) power distribution networks, voltage stability control is achieved through the collaborative operation of various modules. The connection interface module connects the distribution network bus, PV distributed power sources, and community loads via standardized electrical interfaces, while relying on multiple safety protection mechanisms to ensure operational safety. The detection and control module collects data through sensors, determines voltage flicker, and generates energy allocation and voltage compensation commands. The hybrid energy storage module allocates the energy output ratio of batteries and supercapacitors according to the commands, constrains power, and completes energy conversion. The DVR main module calculates the compensation voltage, converts electrical energy, and filters harmonics to smooth out voltage flicker. The energy storage mode management module switches operating modes according to the energy storage status, effectively mitigating voltage flicker caused by fluctuations in PV output and ensuring normal electricity use for residents.

[0035] Example 2:

[0036] Connection Interface Module: In the scenario of stable voltage control for machine tool loads in the industrial power distribution network of a medium-sized machine shop, a standardized electrical interface conforming to the general standards of industrial scenarios is adopted. It connects to the power distribution bus of the medium-sized machine shop, the output terminal of the factory's own diesel generator, and the load input terminal of the machine tool cluster composed of multiple CNC lathes and milling machines. It integrates a dedicated signal transmission interface adapted to the data transmission needs of industrial data transmission. Its built-in safety protection mechanism includes an overcurrent protection mechanism that monitors the transmission line current in real time. When the power distribution network is overloaded and exceeds the safe range due to simultaneous start-up and shutdown of machine tools or short circuit, the fault circuit is cut off. The overvoltage protection mechanism tracks the power distribution network voltage in real time. When the voltage of the power distribution network exceeds the normal operating range due to fluctuations in the diesel generator speed, the voltage clamping function is activated to limit the voltage within the safe operating range of industrial equipment. The lightning protection mechanism absorbs the impact energy when the power distribution network is struck by lightning by integrating lightning protection components adapted to the lightning protection needs of industrial power distribution networks.

[0037] The detection and control module collects voltage amplitude, voltage fluctuation frequency, and voltage phase information from the industrial power distribution network using voltage sensors adapted to the network. It also collects operating current data of the machine tool cluster load using current sensors adapted to the machine tool cluster's current range. Finally, it calculates the flicker perception coefficient using the following formula: When S(t) ≥ S0, it is determined that voltage flicker occurs; at the same time, combined with the short-circuit capacity of the distribution network, the dynamic impedance characteristics of diesel generators, and the transmission law of flicker in industrial distribution networks, the analyzed voltage fluctuations are analyzed to clarify the frequency characteristics and amplitude characteristics of voltage fluctuations. Based on the analysis results and S(t), an energy distribution instruction containing voltage fluctuation frequency and amplitude parameters, as well as a voltage compensation instruction containing flicker perception coefficient and distribution network equivalent impedance parameters, are generated.

[0038] Hybrid energy storage module: After receiving the energy distribution instruction, calculate the energy output ratio of the battery adapted to the industrial load characteristics and the supercapacitor adapted to the high-frequency response requirements of the start and stop of machine tools through the hybrid energy storage energy distribution coefficient formula, and clarify the energy output priority of the battery and the supercapacitor in different voltage fluctuation scenarios. The hybrid energy storage energy distribution coefficient formula is: And constrain the output power of both through the hybrid energy storage charge and discharge power constraint formula to ensure that the battery outputs power normally within the safe range of the remaining battery capacity and the supercapacitor outputs power normally within the safe range of the terminal voltage. The hybrid energy storage charge and discharge power constraint formula is: Then, through a bidirectional DC converter adapted to industrial power requirements, perform power conversion and power distribution of electric energy and output DC electric energy, as Figure 2 shown. At the same time, the energy storage management unit regularly collects data on the remaining battery capacity of the battery and the terminal voltage of the supercapacitor as needed.

[0039] DVR main body module: After receiving the voltage compensation instruction, based on the DC electric energy output by the hybrid energy storage module, calculate the compensation voltage to be output through the DVR compensation voltage calculation formula. The DVR compensation voltage calculation formula is: Through a voltage source inverter adapted to industrial voltage compensation requirements, convert DC electric energy into AC electric energy matching the compensation voltage. At the same time, through a filtering unit adapted to industrial harmonic control requirements, filter out the high-order harmonic components generated during the power conversion process, control the voltage fluctuation of the distribution network within the range that meets the stable operation requirements of the machine tool, suppress the voltage flicker caused by the start and stop of the machine tool load, and ensure that the machining accuracy of the machine tool meets the production standards.

[0040] Energy storage mode management module: When the voltage flicker is eliminated, through the energy storage charge and discharge mode switching condition formula, the energy storage charge and discharge mode switching condition formula is: When S(t) < S0 and SOC(t) < SOC max and U sc (t) < U sc,maxWhen the battery reaches its maximum capacity and the supercapacitor reaches its maximum voltage, the system switches to standby mode, which only maintains real-time monitoring of key data such as current and voltage to ensure that voltage compensation can be quickly put into operation when the machine tool load is started again.

[0041] In summary, for the scenario of stable voltage control of machine tool loads in the industrial power distribution network of a medium-sized machine processing plant, the connection interface module connects to the power distribution bus, diesel generator, and machine tool cluster load using a standard industrial interface, and is equipped with a safety protection mechanism to prevent faults; the detection and control module collects data to determine flicker and generates instructions based on the characteristics of the industrial power distribution network; the hybrid energy storage module adjusts the output ratio of the battery and supercapacitor to adapt to machine tool load fluctuations; the DVR main module completes the compensation voltage calculation, power conversion, and harmonic filtering to ensure voltage stability; and the energy storage mode management module switches the working mode as needed to effectively suppress voltage flicker caused by machine tool load start-up and shutdown, ensuring machine tool processing accuracy and stable equipment operation.

[0042] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A dynamic voltage restorer system based on a hybrid energy storage system of battery and supercapacitor, characterized in that, The system includes: Connection interface module: It adopts a standardized electrical interface to connect with the busbar, distributed power output terminal and load input terminal of the distribution network, integrates a dedicated signal transmission interface and has a built-in safety protection mechanism; Detection and control module: It collects data through voltage and current sensors, calculates the flicker perception coefficient using the voltage flicker perception coefficient formula, analyzes voltage fluctuations when voltage flicker occurs, and generates energy distribution and voltage compensation commands. Hybrid energy storage module: Receives energy distribution instructions, calculates the energy output ratio of the battery and supercapacitor through the hybrid energy storage energy distribution coefficient formula and the hybrid energy storage charge and discharge power constraint formula, constrains the output power, and then performs power conversion and power distribution through a bidirectional DC converter to output DC power. The main DVR module receives voltage compensation commands and calculates the required compensation voltage based on DC power using the DVR compensation voltage calculation formula. It then converts the DC power into AC power that matches the compensation voltage using a voltage source inverter. Simultaneously, it filters out harmonic components generated during the power conversion process through a filter unit to smooth out voltage flicker. Energy storage mode management module: When voltage flicker is eliminated, the hybrid energy storage module switches to hybrid energy storage mode based on the remaining battery capacity and the voltage state of the supercapacitor, according to the energy storage charging and discharging mode switching condition formula.

2. The dynamic voltage restorer system based on battery-supercapacitor hybrid energy storage according to claim 1, characterized in that, The connection interface module includes the following safety protection mechanisms: an overcurrent protection mechanism that monitors the current in the transmission line in real time and cuts off the fault circuit when the distribution network experiences current overload due to a short circuit or sudden load change; an overvoltage protection mechanism that tracks the distribution network voltage in real time and activates the voltage clamping function to limit the voltage to a safe range when the voltage rises suddenly due to a sudden increase in photovoltaic output or other reasons; and a lightning protection mechanism that absorbs the impact energy generated by lightning strikes when the distribution network is struck by lightning by integrating lightning protection components.

3. The dynamic voltage restorer system based on battery-supercapacitor hybrid energy storage according to claim 1, characterized in that, In the detection and control module, real-time signals from the power distribution network, distributed power sources, and loads are received through the connection interface module. Voltage sensors are used to collect information on the voltage amplitude, frequency of voltage fluctuations, and voltage phase of the power distribution network. Current sensors are used to collect the operating current data of the loads. The flicker perception coefficient S(t) is calculated using the voltage flicker perception coefficient formula. With the voltage fluctuation range S0 during normal operation of the power distribution network as a benchmark, when S(t) ≥ S0, it is determined that voltage flicker has occurred.

4. The dynamic voltage restorer system based on battery-supercapacitor hybrid energy storage according to claim 3, characterized in that, In the detection and control module, the formula for the voltage flicker sensing coefficient is: Where S(t) is the voltage flicker perception coefficient at time t, U(t) is the distribution network voltage at time t, and U e t is the rated voltage of the distribution network, f(t) is the voltage fluctuation frequency at time t, and k1 and k2 are correction coefficients.

5. The dynamic voltage restorer system based on battery-supercapacitor hybrid energy storage according to claim 1, characterized in that, In the detection and control module, the short-circuit capacity of the distribution network, the dynamic impedance characteristics of distributed power sources, and the transmission law of flicker in the distribution network are combined to analyze the voltage fluctuations that have occurred, clarify the frequency and amplitude characteristics of the voltage fluctuations, and generate energy distribution commands including voltage fluctuation frequency and amplitude parameters and voltage compensation commands including flicker perception coefficient and distribution network equivalent impedance parameters based on the analysis results and S(t).

6. The dynamic voltage restorer system based on battery-supercapacitor hybrid energy storage according to claim 1, characterized in that, The hybrid energy storage module includes a battery, a supercapacitor, a bidirectional DC-DC converter, and an energy storage management unit. After receiving an energy allocation command, it calculates the energy output ratio of the battery and the supercapacitor using the hybrid energy storage energy allocation coefficient formula, clarifies the energy output priority of the battery and the supercapacitor under different voltage fluctuation scenarios, constrains the output power of the battery and the supercapacitor using the hybrid energy storage charge and discharge power constraint formula, and then performs power conversion and power allocation through the bidirectional DC-DC converter to output DC power. At the same time, the energy storage management unit collects the remaining battery power and the supercapacitor terminal voltage data in real time.

7. The dynamic voltage restorer system based on battery-supercapacitor hybrid energy storage according to claim 6, characterized in that, In the hybrid energy storage module, the formula for the hybrid energy storage energy distribution coefficient is: Where α(t) is the energy output percentage of the battery at time t, 1-α(t) is the energy output percentage of the supercapacitor, f(t) is the voltage fluctuation frequency at time t, f0 is the voltage fluctuation frequency threshold, and ΔU(t)=|U(t)-U e | represents the voltage fluctuation amplitude at time t, ΔU0 is the voltage fluctuation amplitude threshold, and k3 and k4 are the response sensitivity coefficients.

8. The dynamic voltage restorer system based on battery-supercapacitor hybrid energy storage according to claim 6, characterized in that, In the hybrid energy storage module, the hybrid energy storage charging and discharging power constraint formula is: Among them, P bat (t), P sc α(t) represents the output power of the battery and the supercapacitor at time t, respectively; α(t) represents the energy output percentage of the battery at time t; 1-α(t) represents the energy output percentage of the supercapacitor; and SOC(t) represents the remaining battery charge at time t. min SOC max U is the safe threshold for the remaining battery power. sc (t) represents the terminal voltage of the supercapacitor at time t, U sc,min U sc,max This refers to the safe voltage threshold for supercapacitors.

9. The dynamic voltage restorer system based on battery-supercapacitor hybrid energy storage according to claim 1, characterized in that, The main DVR module includes a voltage source inverter and a filter unit; the DVR compensation voltage calculation formula is as follows: Among them, U comp (t) represents the compensation voltage that the DVR needs to output at time t, P stor (t)=P bat (t)+P sc Z(t) represents the total output power at time t. grid θ is the equivalent impedance of the distribution network, θ is the phase difference between the compensation voltage and the distribution network voltage, and S(t) is the flicker sensing coefficient.

10. The dynamic voltage restorer system based on battery-supercapacitor hybrid energy storage according to claim 1, characterized in that, In the energy storage mode management module, the formula for switching energy storage charging and discharging modes is as follows: Where Mode(t) represents the hybrid energy storage operating mode at time t.

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