Urban island load frequency control method and system fusing dynamic sliding mode control and virtual energy storage

Abstract

The application discloses a kind of urban island load frequency control methods of fusing dynamic sliding mode control and virtual energy storage, including obtaining the data information of target island load;Discrete sliding film control and virtual energy storage are constructed with the regional mathematical model of target island load;The corresponding discrete sliding film control model and virtual energy storage action mechanism model are constructed;According to the model constructed, the emergency frequency control of target power system island load is completed.The application also discloses a kind of system for realizing the urban island load frequency control method of fusing dynamic sliding mode control and virtual energy storage of the application.The application not only realizes the emergency frequency control of power system island load, but also has higher reliability and better accuracy.

Description

Technical Field

[0001] This invention belongs to the field of electrical automation, specifically relating to a method and system for controlling the frequency of isolated urban loads that integrates dynamic sliding mode control and virtual energy storage. Background Technology

[0002] With economic and technological development and the improvement of people's living standards, electricity has become an indispensable secondary energy source in people's production and daily life, bringing endless convenience. Therefore, ensuring a stable and reliable supply of electricity has become one of the most important tasks of the power system.

[0003] Currently, an increasing number of new energy power generation systems are being integrated into the power grid and generating electricity. The randomness and intermittency of these systems' output pose significant challenges to the safe and stable operation of the power system. Islanded microgrids are an important component of the power system, and ensuring their safe and stable operation is of paramount importance.

[0004] Whether an islanded microgrid interconnected by power lines can achieve stable operation against interference under the penetration of high-energy power generation systems is a key test of island stability. Currently, load frequency control schemes for islanded microgrids heavily rely on physical energy storage systems. However, the high investment cost of energy storage systems, along with constraints on charging / discharging time and capacity limits, restricts their large-scale deployment. Existing load frequency control schemes suffer from insufficient robustness of controllers under nonlinearity, parameter uncertainty, communication delays, and matched / mismatched disturbances. While traditional sliding diaphragm control schemes suffer from chattering, singularity, and a decrease in convergence rate with system order, sliding diaphragm control schemes incorporating backstepping technology also suffer from term explosion problems due to repeated differentiation of the virtual control law. Summary of the Invention

[0005] One of the objectives of this invention is to provide a highly reliable and accurate method for controlling the frequency of isolated urban loads that integrates dynamic sliding mode control and virtual energy storage.

[0006] The second objective of this invention is to provide a system for implementing the urban island load frequency control method that integrates dynamic sliding mode control and virtual energy storage.

[0007] The urban island load frequency control method integrating dynamic sliding mode control and virtual energy storage provided by this invention includes the following steps:

[0008] S1. Obtain data information on the target island's load;

[0009] S2. Based on the data obtained in step S1, construct a regional mathematical model of the target island load with discrete sliding membrane control and virtual energy storage;

[0010] S3. Based on the model obtained in step S2, construct the corresponding discrete sliding film control model and virtual energy storage mechanism model;

[0011] S4. Based on the model constructed in steps S2 and S3, complete the emergency frequency control of the target power system islanded load.

[0012] Step S1, which involves obtaining data information about the target island load, specifically includes the following steps:

[0013] Obtain data on the target island's load;

[0014] The data information includes the power system time constant. Diesel generator time constant Wind turbine time constant Speed ​​regulation time constant drooping parameters Power system gain Bias factor Integral controller gain Communication delay Load changes Generator output power The connection coefficient between the i-th region and the j-th region Where i represents the region number.

[0015] Step S2, which involves constructing a regional mathematical model of the target islanded load with discrete sliding membrane control and virtual energy storage based on the data obtained in step S1, specifically includes the following steps:

[0016] The following formula is used as the high-order power system differential equation for the target islanded load:

[0017] In the formula for The first derivative; The rate of change of frequency deviation; This refers to changes in generator output; For load disturbance; The rotor angle deviation is for the i-th control region; Total number of regions; for The first derivative; The turbine time constant; For changes in the opening degree of the speed controller valve; for The first derivative; The output of the area control error integral controller; The control signal generated for the discrete sliding diaphragm control model; for The first derivative; for The first derivative; This refers to the rotor angle deviation;

[0018] The frequency change is set as The change in generator output power is The change in the position of the generator governor valve is The output of the integral controller is The rotor angular deviation is The wind power input to the wind turbine generator is The mathematical model for the interconnected islanded microgrid system equipped with a virtual energy storage solution is as follows:

[0019] It includes three control regions: the i-th control region, the j-th control region, and the k-th control region.

[0020] Within the i-th control region, After passing the dead zone, then proceed... Power deviation of the tie line from the i-th control region after amplification The summation, after passing through the integral controller and time delay, yields a secondary control signal. ; After passing the dead zone, then proceed... Magnified quantity After summing with the output of the discrete sliding diaphragm control model, the signal is transmitted through the speed regulator stage. Processed ; Through the diesel generator section Processed The output value of the distributed power source is obtained through a first-order inertial element. Quantity after processing , and After summing, it passes through the load circuit. Processed ; pass Processing steps are obtained ; and Summing and then passing Intermediate quantities obtained from the process steps, and and Summing and then passing The intermediate quantities obtained from each step are added together to obtain the result. ; Obtained through dead zone processing ; and After summing, through Magnify, then pass through The virtual energy storage of the i-th control region is obtained after integral of the steps. ; Superimposed on the generator / load node, a virtual energy buffer is realized within the region, completing the closed-loop control within the i-th region;

[0021] Within the j-th control region, After passing the dead zone, then proceed... Power deviation of the tie line from the j-th control region after amplification The summation, after passing through the integral controller and time delay, yields a secondary control signal. ; After passing the dead zone, then proceed... Magnified quantity After summing with the output of the discrete sliding diaphragm control model, the signal is transmitted through the speed regulator stage. Processed ; Through the diesel generator section Processed The output value of the distributed power source is obtained through a first-order inertial element. Quantity after processing , and After summing, it passes through the load circuit. Processed ; pass Processing steps are obtained ; and Summing and then passing Intermediate quantities obtained from the process steps, and and Summing and then passing The intermediate quantities obtained from each step are added together to obtain the result. ; Obtained through dead zone processing ; and After summing, through Magnify, then pass through The virtual energy storage of the j-th control region is obtained after integral of the steps. ; Superimposed on the generator / load node, it realizes virtual energy buffering within the region and completes closed-loop control within the j-th region;

[0022] In the k-th control region, After passing the dead zone, then proceed... Power deviation of the tie line from the k-th control region after amplification The summation, after passing through the integral controller and time delay, yields a secondary control signal. ; After passing the dead zone, then proceed... Magnified quantity After summing with the output of the discrete sliding diaphragm control model, the signal is transmitted through the speed regulator stage. Processed ; Through the diesel generator section Processed The output value of the distributed power source is obtained through a first-order inertial element. Quantity after processing , and After summing, it passes through the load circuit. Processed ; pass Processing steps are obtained ; and Summing and then passing Intermediate quantities obtained from the process steps, and and Summing and then passing The intermediate quantities obtained from each step are added together to obtain the result. ; Obtained through dead zone processing ; and After summing, through Magnify, then pass through The virtual energy storage of the k-th control region is obtained after integral of the steps. ; Superimposed on the generator / load node, it realizes virtual energy buffering within the region and completes closed-loop control within the j-th region;

[0023] The general state-space expression for constructing the dynamics of interconnected islanded micronets with communication delays is as follows:

[0024] In the formula This is the system state matrix; To control the input matrix; Here is the perturbation distribution matrix; This is the communication delay matrix; For regional interconnection coupling matrix;

[0025] use This represents the uncertainty of the system matrix. This indicates the uncertainty of the control input matrix. This represents the uncertainty of the perturbation distribution matrix. This represents the uncertainty of the communication delay matrix;

[0026] When considering parameter uncertainties, the system dynamics model is expressed as:

[0027] Define aggregation perturbation The aggregation disturbance includes parameter uncertainty, external disturbance, and neighboring cell interconnection disturbance; therefore, the aggregation disturbance... Represented as:

[0028] When considering parameter uncertainties, the system dynamics model expression using aggregated perturbation is expressed as:

[0029] Using state transitions, it can be represented as a controllable canonical form, which is expressed as... .

[0030] Step S3, which involves constructing the corresponding discrete sliding film control model and virtual energy storage mechanism model based on the model obtained in step S2, specifically includes the following steps:

[0031] In the model obtained in step S2, a corresponding discrete sliding diaphragm control model is constructed based on the sliding diaphragm control scheme. The discrete sliding diaphragm control model is located between the regional control error integral controller and the time delay signal, and can simultaneously handle matched disturbances and unmatched disturbances, suppress chattering, solve the term explosion problem, and enhance system stability.

[0032] In the model obtained in step S2, a corresponding virtual energy storage mechanism model is constructed based on the virtual energy storage scheme. The virtual energy storage mechanism model is located between the frequency deviation signal and the regional control error calculation, and is reflected in the dead zone, realizing the free exchange of energy in the control zone and improving the penetration rate of renewable energy.

[0033] The process of constructing a discrete sliding membrane control model includes the following steps:

[0034] The sliding surface is designed as a function of the error variable; the error variable is expressed as... The state variable is represented as The reference value of the state variable is represented as The sliding surface of the nth order dynamics is represented as Then it exists:

[0035] In the formula, n takes the value of ;

[0036] Design a virtual controller for stability. , represented as:

[0037] In the formula For virtual control laws; This is the (n+1)th state variable; The reaching law gain of the sliding surface in the nth step;

[0038] The design has a time constant. A first-order low-pass filter, for After filtering, the following exists:

[0039] In the formula for The first derivative; This is the output of a first-order low-pass filter;

[0040] The final dynamic synovial surface is represented as ;

[0041] The first derivative of the synovial surface is obtained as follows:

[0042] In the formula for The first derivative; For the known part of the system, it is a nonlinear function; For aggregation perturbation; The control input gain of the system after state transformation; This serves as the control input for the discrete sliding diaphragm control model. The derivative of the state reference value;

[0043] Represented as .

[0044] The process of constructing a virtual energy storage mechanism model includes the following steps:

[0045] For the ii-th control region:

[0046] Set the actual frequency of the ii-th control region to be The scheduling frequency is Actual tie-line power is The power of the dispatch tie line is The regional control error of the ii region is The virtual energy stored in the ii-th region is The dead zone limit value is Frequency deviation coefficient is ;

[0047] The conditional logic expression of the constructed virtual energy storage mechanism model is as follows:

[0048] like Then set:

[0049] like Then set:

[0050] like Then set:

[0051] In the formula, ii is the region code, and the value of ii is i, j, and k.

[0052] This invention also provides a system for implementing the aforementioned method for frequency control of urban islanded loads integrating dynamic sliding mode control and virtual energy storage, comprising a data acquisition module, a model building module, a control building module, and a frequency control module; the data acquisition module, model building module, control building module, and frequency control module are connected in series; the data acquisition module is used to acquire data information of the target islanded load and upload the data information to the model building module; the model building module is used to construct a regional mathematical model of the target islanded load with discrete sliding mode control and virtual energy storage based on the received data information and the acquired data information, and upload the data information to the control building module; the control building module is used to construct a corresponding discrete sliding mode control model and a virtual energy storage mechanism model based on the received data information and the obtained model, and upload the data information to the frequency control module; the frequency control module is used to complete the emergency frequency control of the target power system islanded load based on the received data information and the constructed model.

[0053] The urban island load frequency control method and system provided by this invention integrates dynamic sliding mode control and virtual energy storage. By constructing a regional mathematical model with discrete sliding mode control and virtual energy storage for the target island load and performing corresponding control, it not only realizes emergency frequency control of the power system island load, but also has higher reliability and better accuracy. Attached Figure Description

[0054] Figure 1 This is a schematic diagram of the method flow of the present invention.

[0055] Figure 2 This is a schematic diagram of the regional mathematical model of the method of the present invention, which incorporates discrete sliding membrane control and virtual energy storage.

[0056] Figure 3 This is a schematic diagram of the virtual energy storage mechanism model of the method of the present invention.

[0057] Figure 4 This is a schematic diagram of the functional modules of the system of the present invention. Detailed Implementation

[0058] like Figure 1 The diagram shown is a flowchart of the method of the present invention: The urban island load frequency control method disclosed in this invention, which integrates dynamic sliding mode control and virtual energy storage, includes the following steps:

[0059] S1. Obtain data information on the target island load; specifically including the following steps:

[0060] Obtain data on the target island's load;

[0061] The data information includes the power system time constant. Diesel generator time constant Wind turbine time constant Speed ​​regulation time constant drooping parameters Power system gain Bias factor Integral controller gain Communication delay Load changes Generator output power The connection coefficient between the i-th region and the j-th region Where i represents the region number;

[0062] S2. Based on the data obtained in step S1, construct a regional mathematical model of the target islanded load with discrete sliding membrane control and virtual energy storage; specifically including the following steps:

[0063] The following equation is used as the high-order power system differential equation for the target islanded load:

[0064] In the formula for The first derivative; The rate of change of frequency deviation; This refers to changes in generator output; For load disturbance; The rotor angle deviation for the i-th control region; Total number of regions; for The first derivative; The turbine time constant; For changes in the opening degree of the speed controller valve; for The first derivative; The output of the area control error integral controller; The control signal generated for the discrete sliding diaphragm control model; for The first derivative; for The first derivative; This refers to the rotor angle deviation;

[0065] The frequency change is set as The change in generator output power is The change in the position of the generator governor valve is The output of the integral controller is The rotor angular deviation is The wind power input to the wind turbine generator is The mathematical model of the interconnected island microgrid system equipped with a virtual energy storage scheme is constructed as follows: Figure 2 As shown, the model is as follows:

[0066] It includes three control regions: the i-th control region, the j-th control region, and the k-th control region.

[0067] Within the i-th control region, After passing the dead zone, then... Power deviation of the interconnection line from the i-th control region after amplification The summation, after passing through the integral controller and time delay, yields a secondary control signal. ; After passing the dead zone, then... Magnified quantity After summing with the output of the discrete sliding diaphragm control model, the signal is transmitted through the speed regulator stage. Processed ; Through the diesel generator section Processed The output value of the distributed power source is obtained through a first-order inertial element. Quantity after processing , and After summing, it passes through the load circuit. Processed ; pass Processing steps are obtained ; and Summation and then passing Intermediate quantities obtained from the process steps, and and Summation and then passing The intermediate quantities obtained from each step are added together to obtain the result. ; Obtained through dead zone processing ; and After summing, through Magnify, then pass through The virtual energy storage of the i-th control region is obtained after integral of the steps. ; Superimposed on the generator / load node, a virtual energy buffer is realized within the region, completing the closed-loop control within the i-th region;

[0068] Within the j-th control region, After passing the dead zone, then... Power deviation of the tie line from the j-th control region after amplification The summation, after passing through the integral controller and time delay, yields a secondary control signal. ; After passing the dead zone, then... Magnified quantity After summing with the output of the discrete sliding diaphragm control model, the signal is transmitted through the speed regulator stage. Processed ; Through the diesel generator section Processed The output value of the distributed power source is obtained through a first-order inertial element. Quantity after processing , and After summing, it passes through the load circuit. Processed ; pass Processing steps are obtained ; and Summation and then passing Intermediate quantities obtained from the process steps, and and Summation and then passing The intermediate quantities obtained from each step are added together to obtain the result. ; Obtained through dead zone processing ; and After summing, through Magnify, then pass through The virtual energy storage of the j-th control region is obtained after integral of the steps. ; Superimposed on the generator / load node, it realizes virtual energy buffering within the region and completes closed-loop control within the j-th region;

[0069] In the k-th control region, After passing the dead zone, then... Power deviation of the tie line from the k-th control region after amplification The summation, after passing through the integral controller and time delay, yields a secondary control signal. ; After passing the dead zone, then... Magnified quantity After summing with the output of the discrete sliding diaphragm control model, the signal is transmitted through the speed regulator stage. Processed ; Through the diesel generator section Processed The output value of the distributed power source is obtained through a first-order inertial element. Quantity after processing , and After summing, it passes through the load circuit. Processed ; pass Processing steps are obtained ; and Summation and then passing Intermediate quantities obtained from the process steps, and and Summation and then passing The intermediate quantities obtained from each step are added together to obtain the result. ; Obtained through dead zone processing ; and After summing, through Magnify, then pass through The virtual energy storage of the k-th control region is obtained after integral of the steps. ; Superimposed on the generator / load node, it realizes virtual energy buffering within the region and completes closed-loop control within the j-th region;

[0070] The general state-space expression for constructing the dynamics of interconnected islanded micronets with communication delays is as follows:

[0071] In the formula This is the system state matrix; To control the input matrix; Here is the perturbation distribution matrix; This is the communication delay matrix; For regional interconnection coupling matrix;

[0072] use This represents the uncertainty of the system matrix. This indicates the uncertainty of the control input matrix. This represents the uncertainty of the perturbation distribution matrix. This represents the uncertainty of the communication delay matrix;

[0073] When considering parameter uncertainties, the system dynamics model is expressed as:

[0074] Define aggregation perturbation The aggregation disturbance includes parameter uncertainty, external disturbance, and neighboring cell interconnection disturbance; therefore, the aggregation disturbance... Represented as:

[0075] When considering parameter uncertainties, the system dynamics model expression using aggregated perturbation is expressed as:

[0076] Using state transitions, it can be represented as a controllable canonical form, which is expressed as... ;

[0077] S3. Based on the model obtained in step S2, construct the corresponding discrete sliding film control model and virtual energy storage mechanism model; specifically including the following steps:

[0078] In the model obtained in step S2, a corresponding discrete sliding diaphragm control model is constructed based on the sliding diaphragm control scheme. The discrete sliding diaphragm control model is located between the regional control error integral controller and the time delay signal, and can simultaneously handle matched disturbances and unmatched disturbances, suppress chattering, solve the term explosion problem, and enhance system stability.

[0079] In the model obtained in step S2, a corresponding virtual energy storage mechanism model is constructed based on the virtual energy storage scheme. The virtual energy storage mechanism model is located between the frequency deviation signal and the regional control error calculation, and is reflected in the dead zone, realizing the free exchange of energy in the control zone and improving the penetration rate of renewable energy.

[0080] In practice, the process of constructing a discrete sliding membrane control model includes the following steps:

[0081] Since the sliding surface is a plane in the state space, the system trajectory is forced to converge and remain on this plane, ensuring system stability; therefore, the sliding surface is designed as a function of the error variable; the error variable is expressed as... The state variable is represented as The reference value of the state variable is represented as The sliding surface of the nth order dynamics is represented as Then it exists:

[0082] In the formula, n takes the value of ;

[0083] Design a virtual controller for stability. , represented as:

[0084] In the formula For virtual control laws; This is the (n+1)th state variable; The reaching law gain of the sliding surface in the nth step;

[0085] Analogous to the first sliding surface, and avoiding the term explosion problem caused by dynamic surface trajectories; designed with a time constant. A first-order low-pass filter, for After filtering, the following exists:

[0086] In the formula for The first derivative; This is the output of a first-order low-pass filter;

[0087] The final dynamic synovial surface is represented as ;

[0088] The first derivative of the synovial surface is obtained as follows:

[0089] In the formula for The first derivative; For the known part of the system, it is a nonlinear function; For aggregation perturbation; The control input gain of the system after state transformation; This serves as the control input for the discrete sliding diaphragm control model. The derivative of the state reference value;

[0090] Represented as ;

[0091] In practice, the process of constructing a virtual energy storage mechanism model includes the following steps:

[0092] The purpose of virtual energy storage is to combine frequency drift within the safety-defined range with the diversity of zone control errors (ACE) to establish virtual storage across the balancing mechanism; the excess energy required to restore the zone frequency to its nominal value needs to be regarded as virtual energy (VE) stored in each control zone; therefore, each zone can effectively act as virtual energy storage for other zones;

[0093] Suppose that the demand in control region 1 suddenly decreases (or increases); therefore, the system frequency will rise (or fall) accordingly; if the frequency exceeds the upper limit, the control regions are considered to be collecting virtual energy (VE); otherwise, they operate in discharge mode; as Figure 3 As shown, when three regions are interconnected, the virtual energy (VE) of each region can be transferred to each other through frequency detection, realizing virtual energy storage exchange within the control area; in the figure This represents the interconnection line between the i-th region and the j-th region, where ;

[0094] For the ii-th control region:

[0095] Set the actual frequency of the ii-th control region to be The scheduling frequency is Actual tie-line power is The power of the dispatch tie line is The regional control error of the ii region is The virtual energy stored in the ii-th region is The dead zone limit value is Frequency deviation coefficient is ;

[0096] The conditional logic expression of the constructed virtual energy storage mechanism model is as follows:

[0097] like Then set:

[0098] like Then set:

[0099] like Then set:

[0100] In the formula, ii is the region code, and the value of ii is i, j, and k;

[0101] When load disturbances occur, the resulting frequency deviation is filtered out by the dead zone; the control system captures the filtered frequency deviation and tie-line power signal to create the area control error (ACE); when The discrete sliding diaphragm controller operates at zero. When the frequency deviation exceeds the drift limit (below or above the drift limit), the control signal will respectively... or The mechanism of action of the dead zone is expressed as follows:

[0102] S4. Based on the model constructed in steps S2 and S3, complete the emergency frequency control of the target power system islanded loads to achieve disturbance rejection and renewable energy consumption in multi-interconnected islanded microgrids.

[0103] This invention addresses the chattering problem and eliminates singularity issues by designing a mechanism that combines a discrete sliding diaphragm controller with virtual energy storage. It also enables the collection and storage of free energy from the inherent characteristics of interconnected islanded microgrid regulation. At the system stability domain level, the discrete sliding diaphragm controller, through its robustness to mismatch disturbances and communication delays, allows for a more relaxed frequency deviation through the virtual energy storage strategy. This successfully improves the anti-interference capability and renewable energy absorption capacity of interconnected islanded microgrids without increasing physical hardware costs.

[0104] The present invention introduces a first-order low-pass filter into the virtual control law design stage of the traditional backstepping sliding mode controller, thereby transforming the dynamic response of the control system from "term explosion" and severe chattering to smooth convergence. This reduces the computational and execution pressure on the controller, suppresses overshoot abrupt changes in system frequency and tie-line power, and expands the asymptotic stability region of the system.

[0105] The present invention effectively suppresses disturbances by combining and improving traditional sliding mode control, ensuring that the system frequency remains stable under random load fluctuations and drastic changes in system parameters. At the same time, it uses virtual energy storage to collect and store free energy from multiple islanded power grids through interconnection lines at low cost, thereby integrating new energy consumption to a greater extent without affecting the stability of system frequency.

[0106] like Figure 4 The diagram shows the functional modules of the system of this invention: The system disclosed in this invention for implementing the urban islanded load frequency control method integrating dynamic sliding mode control and virtual energy storage includes a data acquisition module, a model building module, a control building module, and a frequency control module; the data acquisition module, model building module, control building module, and frequency control module are connected in series; the data acquisition module is used to acquire data information of the target islanded load and upload the data information to the model building module; the model building module is used to construct a regional mathematical model of the target islanded load with discrete sliding mode control and virtual energy storage based on the received data information and the acquired data information, and upload the data information to the control building module; the control building module is used to construct the corresponding discrete sliding mode control model and virtual energy storage mechanism model based on the received data information and the obtained model, and upload the data information to the frequency control module; the frequency control module is used to complete the emergency frequency control of the target power system islanded load based on the received data information and the constructed model.

Claims

1. A method for frequency control of urban islanded loads that integrates dynamic sliding mode control and virtual energy storage, comprising the following steps: S1. Obtain data information on the target isolated load; S2. Based on the data obtained in step S1, construct a regional mathematical model of the target island load with discrete sliding membrane control and virtual energy storage; S3. Based on the model obtained in step S2, construct the corresponding discrete sliding film control model and virtual energy storage mechanism model; S4. Based on the model constructed in steps S2 and S3, complete the emergency frequency control of the target power system islanded load.

2. The urban island load frequency control method integrating dynamic sliding mode control and virtual energy storage as described in claim 1, characterized in that... Step S1, which involves obtaining data information about the target island load, specifically includes the following steps: Obtain data on the target island's load; The data information includes the power system time constant. Diesel generator time constant Wind turbine time constant Speed ​​regulation time constant drooping parameters Power system gain Bias factor Integral controller gain Communication delay Load changes Generator output power The connection coefficient between the i-th region and the j-th region Where i represents the region number.

3. The urban island load frequency control method integrating dynamic sliding mode control and virtual energy storage according to claim 2, characterized in that... Step S2, which involves constructing a regional mathematical model of the target islanded load with discrete sliding membrane control and virtual energy storage based on the data obtained in step S1, specifically includes the following steps: The following equation is used as the high-order power system differential equation for the target islanded load: In the formula for The first derivative; The rate of change of frequency deviation; This refers to changes in generator output; For load disturbance; The rotor angle deviation for the i-th control region; Total number of regions; for The first derivative; The turbine time constant; For changes in the opening degree of the speed controller valve; for The first derivative; The output of the area control error integral controller; The control signal generated for the discrete sliding diaphragm control model; for The first derivative; for The first derivative; This refers to the rotor angle deviation; The frequency change is set as The change in generator output power is The change in the position of the generator governor valve is The output of the integral controller is The rotor angular deviation is The wind power input to the wind turbine generator is The mathematical model for the interconnected islanded microgrid system equipped with a virtual energy storage solution is as follows: It includes three control regions: the i-th control region, the j-th control region, and the k-th control region. Within the i-th control region, After passing the dead zone, then... Power deviation of the interconnection line from the i-th control region after amplification The summation, after passing through the integral controller and time delay, yields a secondary control signal. ; After passing the dead zone, then... Magnified quantity After summing with the output of the discrete sliding diaphragm control model, the signal is transmitted through the speed regulator stage. Processed ; Through the diesel generator section Processed The output value of the distributed power source is obtained through a first-order inertial element. Quantity after processing , and After summing, it passes through the load circuit. Processed ; pass Processing steps are obtained ; and Summation and then passing Intermediate quantities obtained from the process steps, and and Summation and then passing The intermediate quantities obtained from each step are added together to obtain the result. ; Obtained through dead zone processing ; and After summing, through Magnify, then pass through The virtual energy storage of the i-th control region is obtained after integral of the steps. ; Superimposed on the generator / load node, a virtual energy buffer is realized within the region, completing the closed-loop control within the i-th region; Within the j-th control region, After passing the dead zone, then... Power deviation of the tie line from the j-th control region after amplification The summation, after passing through the integral controller and time delay, yields a secondary control signal. ; After passing the dead zone, then... Magnified quantity After summing with the output of the discrete sliding diaphragm control model, the signal is transmitted through the speed regulator stage. Processed ; Through the diesel generator section Processed The output value of the distributed power source is obtained through a first-order inertial element. Quantity after processing , and After summing, it passes through the load circuit. Processed ; pass Processing steps are obtained ; and Summation and then passing Intermediate quantities obtained from the process steps, and and Summation and then passing The intermediate quantities obtained from each step are added together to obtain the result. ; Obtained through dead zone processing ; and After summing, through Magnify, then pass through The virtual energy storage of the j-th control region is obtained after integral of the steps. ; Superimposed on the generator / load node, it realizes virtual energy buffering within the region and completes closed-loop control within the j-th region; In the k-th control region, After passing the dead zone, then... Power deviation of the tie line from the k-th control region after amplification The summation, after passing through the integral controller and time delay, yields a secondary control signal. ; After passing the dead zone, then... Magnified quantity After summing with the output of the discrete sliding diaphragm control model, the signal is transmitted through the speed regulator stage. Processed ; Through the diesel generator section Processed The output value of the distributed power source is obtained through a first-order inertial element. Quantity after processing , and After summing, it passes through the load circuit. Processed ; pass Processing steps are obtained ; and Summation and then passing Intermediate quantities obtained from the process steps, and and Summation and then passing The intermediate quantities obtained from each step are added together to obtain the result. ; Obtained through dead zone processing ; and After summing, through Magnify, then pass through The virtual energy storage of the k-th control region is obtained after integral of the steps. ; Superimposed on the generator / load node, it realizes virtual energy buffering within the region and completes closed-loop control within the j-th region; The general state-space expression for constructing the dynamics of interconnected islanded micronets with communication delays is as follows: In the formula This is the system state matrix; To control the input matrix; Here is the perturbation distribution matrix; This is the communication delay matrix; For regional interconnection coupling matrix; use This represents the uncertainty of the system matrix. This indicates the uncertainty of the control input matrix. This represents the uncertainty of the perturbation distribution matrix. This represents the uncertainty of the communication delay matrix; When considering parameter uncertainties, the system dynamics model is expressed as: Define aggregation perturbation The aggregation disturbance includes parameter uncertainty, external disturbance, and neighboring cell interconnection disturbance; therefore, the aggregation disturbance... Represented as: When considering parameter uncertainties, the system dynamics model expression using aggregated perturbation is expressed as: Using state transitions, it can be represented as a controllable canonical form, which is expressed as... .

4. The urban island load frequency control method integrating dynamic sliding mode control and virtual energy storage according to claim 3, characterized in that... Step S3, which involves constructing the corresponding discrete sliding film control model and virtual energy storage mechanism model based on the model obtained in step S2, specifically includes the following steps: In the model obtained in step S2, a corresponding discrete sliding diaphragm control model is constructed based on the sliding diaphragm control scheme. The discrete sliding diaphragm control model is located between the regional control error integral controller and the time delay signal, and can simultaneously handle matched disturbances and unmatched disturbances, suppress chattering, solve the term explosion problem, and enhance system stability. In the model obtained in step S2, a corresponding virtual energy storage mechanism model is constructed based on the virtual energy storage scheme. The virtual energy storage mechanism model is located between the frequency deviation signal and the regional control error calculation, and is reflected in the dead zone, realizing the free exchange of energy in the control zone and improving the penetration rate of renewable energy.

5. The urban island load frequency control method integrating dynamic sliding mode control and virtual energy storage according to claim 4, characterized in that... The process of constructing a discrete sliding membrane control model includes the following steps: The sliding surface is designed as a function of the error variable; Error variable is represented as The state variable is represented as The reference value of the state variable is represented as The sliding surface of the nth order dynamics is represented as Then it exists: In the formula, n takes the value of ; Design a virtual controller for stability. , represented as: In the formula For virtual control laws; This is the (n+1)th state variable; The reaching law gain of the sliding surface in the nth step; The design has a time constant. A first-order low-pass filter, for After filtering, the following exists: In the formula for The first derivative; This is the output of a first-order low-pass filter; The final dynamic synovial surface is represented as ; The first derivative of the synovial surface is obtained as follows: In the formula for The first derivative; For the known part of the system, it is a nonlinear function; For aggregation perturbation; The control input gain of the system after state transformation; This serves as the control input for the discrete sliding diaphragm control model. The derivative of the state reference value; Represented as .

6. The urban island load frequency control method integrating dynamic sliding mode control and virtual energy storage according to claim 4, characterized in that... The process of constructing a virtual energy storage mechanism model includes the following steps: For the ii-th control region: Set the actual frequency of the ii-th control region to be The scheduling frequency is Actual tie-line power is The power of the dispatch tie line is The regional control error of the ii region is The virtual energy stored in the ii-th region is The dead zone limit value is Frequency deviation coefficient is ; The conditional logic expression of the constructed virtual energy storage mechanism model is as follows: like Then set: like Then set: like Then set: In the formula, ii is the region code, and the value of ii is i, j, and k.

7. A system for implementing the urban island load frequency control method integrating dynamic sliding mode control and virtual energy storage as described in any one of claims 1 to 6, characterized in that... It includes a data acquisition module, a model building module, a control building module, and a frequency control module; these modules are connected in series. The data acquisition module acquires data information of the target islanded load and uploads it to the model building module. The model building module constructs a regional mathematical model of the target islanded load with discrete sliding membrane control and virtual energy storage based on the received and acquired data information, and uploads the model to the control building module. The control building module constructs the corresponding discrete sliding membrane control model and virtual energy storage mechanism model based on the received data information and the obtained model, and uploads the model to the frequency control module. The frequency control module is used to perform emergency frequency control for the target power system islanded load based on the received data and the constructed model.

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