Method and system for suppressing low-frequency oscillation of network construction type energy storage converter

Abstract

The invention discloses a method and a system for suppressing low-frequency oscillation of a network construction type energy storage converter, and belongs to the technical field of energy storage, and the method comprises the following steps: constructing a small-signal impedance model of the network construction type energy storage converter based on virtual admittance control by using a small-signal modeling method; order reduction simplification is carried out on the impedance model, key characteristics of a 0.1-10Hz synchronous frequency band are reserved, and oscillation core inducements in a current steady-state value matrix are identified; and adding a q-axis voltage feedforward control link, introducing a regulation coefficient, and modifying the regulation coefficient to enable the modified regulation coefficient to be negative to counteract oscillation inducements. The method can effectively suppress the interactive oscillation of the grid-forming type energy storage converter and the power grid at the low frequency band, improves the system stability, is suitable for various operation conditions, and has important engineering application value.

Description

Technical Field

[0001] This invention belongs to the field of energy storage technology, specifically relating to a method and system for suppressing low-frequency oscillations in a grid-type energy storage converter. Background Technology

[0002] With the grid connection of a high proportion of renewable energy (such as wind power and photovoltaics) and the large-scale application of power electronic equipment, the inertia and damping characteristics of traditional power systems have been significantly weakened. This not only leads to a significant decrease in voltage and frequency stability, but also easily causes broadband oscillations under electromagnetic transients, seriously threatening the safe operation of the system.

[0003] Grid-based energy storage converters, with their stable energy support capabilities, instantaneous power response mechanisms, and voltage source characteristics, can autonomously respond to changes in system voltage and frequency, participating in frequency and voltage control before and after disturbances of varying magnitudes, thus becoming a core active support resource for the stable operation of new power systems. However, in multi-unit parallel operation scenarios, they are prone to low-frequency oscillations due to control parameter mismatches; especially under high-power charging and discharging conditions, the interaction between the converter and the grid, and between the converters themselves, intensifies, making the oscillation phenomenon even more prominent, which has become a key bottleneck restricting the reliable operation of energy storage systems.

[0004] Existing methods for suppressing low-frequency oscillations mostly rely on traditional control parameter optimization and passive damping techniques, which have significant limitations: First, there is a lack of accurate impedance characteristic analysis. Most of the analysis is based on simplified system models and does not fully consider the core impedance characteristics of grid-type energy storage converters in the synchronous frequency band, resulting in insufficient targeting of control strategies. Secondly, the parameters have poor adaptability. Using fixed control parameters makes it difficult to adapt to the dynamic adjustment of system operating conditions (such as power fluctuations and changes in grid parameters). Under weak grid conditions, parameter mismatch can easily trigger oscillations again. Third, the suppression effect is limited. It only alleviates the problem through local optimization measures, but does not block the root cause of oscillation from the perspective of system impedance reshaping, and cannot effectively suppress low-frequency interactive oscillation. Fourth, the lack of identification of key factors and the failure to accurately locate the core parameters affecting system stability have led to a significant reduction in the targeting and effectiveness of control strategies.

[0005] Therefore, there is an urgent need for a low-frequency oscillation solution for grid-type energy storage converters that can accurately analyze impedance characteristics, dynamically adapt parameters, and suppress oscillations at their source, so as to ensure the safe and stable operation of the new power system. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a method and system for suppressing low-frequency oscillations in grid-type energy storage converters, which addresses the shortcomings of the prior art and solves the technical problem of low-frequency oscillations under high power during the charging and discharging process of grid-type energy storage converters, thereby improving the safe and stable operation level of the energy storage system.

[0007] The present invention adopts the following technical solution: A method for suppressing low-frequency oscillations in a grid-type energy storage converter includes the following steps: S1. Construct the impedance model of the grid-type energy storage converter using the small-signal modeling method to obtain the small-signal impedance model of the grid-type energy storage converter based on virtual admittance control. S2. The impedance model of the grid-type energy storage converter obtained in step S1 is simplified by reducing its order. During the simplification process, its key impedance characteristics in the synchronous frequency band are retained, while the filter capacitor, active power loop transfer function, current loop decoupling matrix, and filter inductor are ignored. The steady-state current matrix is ​​then identified. elements in It is a key factor affecting stability; S3. The impedance model of the grid-type energy storage converter obtained in step S2 is reshaped by adding a q-axis voltage feedforward control loop to the control system and introducing a regulation coefficient. The current steady-state value matrix elements in Modified to ,in, The preset parameters related to the q-axis voltage feedforward control suppress the interaction behavior between the grid-type energy storage converter and the power grid in the low-frequency band, thereby reducing low-frequency oscillations.

[0008] Preferably, in step S1, the impedance matrix of the dq coordinate system is transformed to the stationary coordinate system and an impedance transformation is performed. The impedance matrix in the stationary coordinate system... Represented as:

[0009] Wherein, the synchronization angular frequency is , This represents the frequency offset between the stationary coordinate system and the synchronously rotating dq coordinate system.

[0010] Preferably, the impedance matrix of the small-signal impedance model of the grid-type energy storage converter in the synchronously rotating dq coordinate system. for: .

[0011] Preferably, in step S2, the impedance simplified model of the grid-type energy storage converter in the dq coordinate system is... Represented as:

[0012] in, The correlation matrix of the filter inductor. This is the relevant matrix for the current loop PI controller. The reactive power loop related transfer function, This is the voltage loop correlation matrix. This is the voltage steady-state value matrix. This is the current steady-state value matrix. It is an identity matrix.

[0013] Preferably, identifying key factors includes determining the steady-state current matrix through actual testing and simulation in a weak network environment. elements in Ignoring the filter capacitor, active power loop transfer function, current loop decoupling matrix, and filter inductor is achieved through model order reduction.

[0014] Preferably, in step S2, the synchronization frequency band is 0.1~10Hz.

[0015] Preferably, in step S3, the current matrix after introducing the control matrix strategy... Represented as:

[0016] in, The current steady-state value matrix Preset elements in This refers to the modified element.

[0017] Preferably, the control coefficient The range of values ​​is , making If the value is negative, the error is eliminated. Negative impact on stability.

[0018] Preferably, in step S3, the q-axis voltage feedforward control loop acquires the q-axis output voltage signal of the grid-type energy storage converter in real time, and dynamically adjusts the preset parameters based on the acquired voltage signal. The value of .

[0019] Preferably, in step S3, during the process of suppressing the interaction between the grid-connected energy storage converter and the power grid in the low-frequency band, the output current fluctuation amplitude of the grid-connected energy storage converter is monitored in real time. If the fluctuation amplitude exceeds a preset threshold, the control coefficient is increased. The value of .

[0020] Secondly, embodiments of the present invention provide a low-frequency oscillation suppression system for a grid-type energy storage converter, comprising: Impedance module is used to construct the impedance model of grid-type energy storage converter using small-signal modeling method, and obtain the small-signal impedance model of grid-type energy storage converter based on virtual admittance control. The simplification module reduces the order of the impedance model of the grid-type energy storage converter obtained by the impedance module. During simplification, it retains the key impedance characteristics within the synchronous frequency band, ignores the filter capacitor, active power loop transfer function, current loop decoupling matrix, and filter inductor, and identifies the steady-state current matrix. elements in It is a key factor affecting stability; The reshaping module reshapes the impedance model of the grid-type energy storage converter obtained from the simplification module by adding a q-axis voltage feedforward control loop and introducing a regulation coefficient. The current steady-state value matrix elements in Modified to ,in, The preset parameters related to the q-axis voltage feedforward control suppress the interaction behavior between the grid-type energy storage converter and the power grid in the low-frequency band, thereby reducing low-frequency oscillations.

[0021] Preferably, in the impedance module, the impedance matrix in the dq coordinate system is transformed to the stationary coordinate system and an impedance transformation is performed. The impedance matrix in the stationary coordinate system... Represented as:

[0022] Impedance matrix of small-signal impedance model of grid-type energy storage converter in synchronous rotating dq coordinate system for:

[0023] Wherein, the synchronization angular frequency is , This represents the frequency offset between the stationary coordinate system and the synchronously rotating dq coordinate system.

[0024] Preferably, in the simplified module, identifying key factors includes determining the steady-state current matrix through actual testing and simulation in a weak network environment. elements in The omission of filter capacitors, active power loop transfer function, current loop decoupling matrix, and filter inductor is achieved through model order reduction. The synchronization frequency band is 0.1~10Hz. The simplified impedance model of the grid-type energy storage converter in the dq coordinate system is described. Represented as:

[0025] in, The correlation matrix of the filter inductor. This is the relevant matrix for the current loop PI controller. The reactive power loop related transfer function, This is the voltage loop correlation matrix. This is the voltage steady-state value matrix. This is the current steady-state value matrix. It is an identity matrix.

[0026] Preferably, in the reshaping module, the current matrix after introducing the control matrix strategy... Represented as:

[0027] in, The current steady-state value matrix Preset elements in For the modified element; The control coefficient The range of values ​​is , making If the value is negative, the error is eliminated. Negative impact on stability.

[0028] Preferably, in the reshaping module, the q-axis voltage feedforward control loop acquires the q-axis output voltage signal of the grid-type energy storage converter in real time, and dynamically adjusts the preset parameters based on the acquired voltage signal. The value of is determined by monitoring the output current fluctuation amplitude of the grid-connected energy storage converter in real time during the process of suppressing the interaction between the grid-connected energy storage converter and the power grid in the low-frequency band. If the fluctuation amplitude exceeds the preset threshold, the control coefficient is increased. The value of .

[0029] Thirdly, a computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the computer program, implements the steps of the above-described method for suppressing low-frequency oscillations in a grid-type energy storage converter.

[0030] Fourthly, embodiments of the present invention provide a computer-readable storage medium including a computer program, which, when executed by a processor, implements the steps of the above-described method for suppressing low-frequency oscillations in a grid-type energy storage converter.

[0031] Fifthly, a chip includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the above-described method for suppressing low-frequency oscillations in a grid-type energy storage converter.

[0032] In a sixth aspect, embodiments of the present invention provide an electronic device including a computer program, wherein when the computer program is executed by the electronic device, it implements the steps of the above-described method for suppressing low-frequency oscillations in a grid-type energy storage converter.

[0033] Compared with the prior art, the present invention has at least the following beneficial effects: A method for suppressing low-frequency oscillations in grid-type energy storage converters is proposed. First, an accurate impedance model is constructed. Then, key impedance characteristics are extracted through a scientific and reasonable order reduction method. Finally, impedance reshaping is achieved by introducing q-axis voltage feedforward control and regulation coefficients. No hardware structure modifications are required; oscillation suppression is achieved solely through control strategy optimization. This method is highly adaptable and can cover grid-type energy storage converters with different power levels and operating modes. It effectively fills the gap in existing passive suppression technologies and blocks the low-frequency interactive oscillation path at its source.

[0034] Furthermore, through coordinate transformation and impedance transformation, accurate characterization of impedance properties in different coordinate systems was achieved. The frequency shift between the synchronously rotating coordinate system and the stationary coordinate system was considered, ensuring the consistency of the impedance model in different reference systems and providing an accurate mathematical model foundation for subsequent impedance analysis and reshaping.

[0035] Furthermore, the specific expression form of the small-signal impedance matrix was clarified, providing a complete mathematical framework for impedance characteristic analysis. Through matrix-based impedance characterization, the impedance characteristics of the system in different dimensions can be comprehensively reflected, providing sufficient theoretical basis for stability analysis and control design.

[0036] Furthermore, a simplified impedance model expression is proposed, which retains the key impedance characteristics within the synchronization frequency band while reducing model complexity through reasonable simplification. This approach ensures both the accuracy of the model and its practicality, facilitating engineering applications.

[0037] Furthermore, practical testing and simulation verification under weak network conditions ensured the accuracy of key factor identification. This method, combining theoretical analysis and experimental verification, improves the credibility and practicality of the technical solution.

[0038] Furthermore, the synchronization frequency range was clarified to be 0.1-10Hz, which is precisely the region where low-frequency oscillations are most likely to occur. By optimizing the impedance characteristics for this specific frequency band, precise oscillation suppression can be achieved.

[0039] Furthermore, a specific impedance reshaping method is provided by introducing a control matrix strategy. This method effectively alters the system's impedance characteristics by modifying key elements in the current matrix, thereby suppressing low-frequency oscillations.

[0040] Furthermore, the range of values ​​for the control coefficient was clarified by setting...k The condition of >1 ensures the effectiveness of impedance reshaping. The determination of this parameter range is based on in-depth theoretical analysis and experimental verification, and has a clear technical basis.

[0041] Furthermore, adaptive control was achieved by acquiring the q-axis output voltage signal in real time and dynamically adjusting the parameters. This allows for automatic optimization of control parameters based on the system's operating status, improving the system's adaptability and robustness.

[0042] Furthermore, an adaptive control mechanism based on output current fluctuation monitoring is provided, which ensures the stability of the system under various operating conditions through real-time monitoring and parameter adjustment.

[0043] It is understood that the beneficial effects of the second to sixth aspects mentioned above can be found in the relevant descriptions in the first aspect mentioned above, and will not be repeated here.

[0044] In summary, the method of this invention achieves efficient suppression of low-frequency oscillations by precisely targeting key causes and dynamically adjusting control parameters. It has strong adaptability and high robustness, effectively solving the problems of limited suppression effect and poor adaptability of existing technologies, and providing a reliable guarantee for the stable operation of grid-type energy storage converters.

[0045] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0046] Figure 1 A small-signal impedance model for a grid-type energy storage converter based on virtual admittance control; Figure 2 A simplified model of a grid-type energy storage converter; Figure 3 This is a small-signal model of a grid-type energy storage converter that has been redesigned and adopts an optimized control strategy. Figure 4 This is a flowchart of the method of the present invention; Figure 5 A schematic diagram of a computer device provided in an embodiment of the present invention; Figure 6 This is a block diagram of a chip provided according to an embodiment of the present invention.

[0047] Among them, 60. Computer equipment; 61. Processor; 62. Memory; 63. Computer program; 600. Electronic device; 610. Processing unit; 620. Storage unit; 6201. Random access memory unit; 6202. Cache memory unit; 6203. Read-only memory unit; 6204. Program / utility; 6205. Program module; 630. Bus; 640. Display unit; 650. Input / output interface; 660. Network adapter; 700. External device. Detailed Implementation

[0048] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] In the description of this invention, it should be understood that the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0050] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0051] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Additionally, the character " / " in this invention generally indicates that the preceding and following objects have an "or" relationship.

[0052] It should be understood that although terms such as first, second, third, etc., may be used in the embodiments of the present invention to describe the preset range, these preset ranges should not be limited to these terms. These terms are only used to distinguish the preset ranges from one another. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0053] Depending on the context, the word "if" as used here can be interpreted as "when," "when," "in response to determination," or "in response to detection." Similarly, depending on the context, the phrase "if determination" or "if detection (of the stated condition or event)" can be interpreted as "when determination," "in response to determination," "when detection (of the stated condition or event)," or "in response to detection (of the stated condition or event)."

[0054] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0055] This invention provides a method for suppressing low-frequency oscillations in grid-type energy storage converters. It reshapes the impedance model of the grid-type energy storage converter and identifies the current term, a key factor affecting stability. By adding a control coefficient and reshaping and optimizing the impedance model of the grid-type energy storage converter, the interaction behavior between the grid-type energy storage converter and the power grid in the low-frequency band is effectively suppressed, the probability of low-frequency oscillation is reduced, and the system is guaranteed to remain stable.

[0056] Please see Figure 4 The present invention discloses a method for suppressing low-frequency oscillations in a grid-type energy storage converter, comprising the following steps: S1. Construct the impedance model of the grid-type energy storage converter using the small-signal modeling method to obtain the small-signal impedance model of the grid-type energy storage converter based on virtual admittance control. Please see Figure 1 The impedance expression of the small-signal impedance model is shown in (1), and is expressed in matrix form as follows: (1) in, This represents the impedance matrix of a grid-type energy storage system in a synchronously rotating dq coordinate system.

[0057] Transform the impedance matrix in the dq coordinate system to the stationary coordinate system and perform an impedance transformation. The impedance matrix in the stationary coordinate system... Represented as: (2) Wherein, the synchronization angular frequency is , This represents the frequency offset between the stationary coordinate system and the synchronously rotating dq coordinate system.

[0058] Furthermore, the power grid impedance matrix in the stationary coordinate system The expression is: (3) S2. The impedance model of the grid-type energy storage converter is simplified by reducing its order. During the simplification process, its key impedance characteristics in the synchronous frequency band are retained, while the filter capacitor, active loop transfer function, current loop decoupling matrix and filter inductor are ignored. Please see Figure 2 The impedance simplification of the grid-type energy storage converter in the dq coordinate system is shown in equation (4): (4) When a grid-type energy storage converter operates in different working modes, its impact on the impedance characteristic curve is mainly reflected in the current steady-state value matrix dynamically introduced by the reactive power loop. and voltage steady-state value matrix The steady-state current matrix was obtained through actual testing and simulation in a weak network environment. This is the key factor causing oscillations in grid-type energy storage converters. Current terms in the matrix It is a key factor affecting stability.

[0059] S3. Reshaping the impedance model of a grid-type energy storage converter is crucial for ensuring its stable operation. This involves offsetting or reshaping the impedance model. This has a negative impact on system stability. Therefore, a q-axis voltage feedforward control loop is added to the control system, and the control strategy is optimized to obtain an optimized impedance model for the grid-type energy storage converter.

[0060] Please see Figure 3 This diagram illustrates the core control logic for low-frequency oscillation suppression, visually demonstrating the signal interaction path and the mechanism of optimized control strategy after impedance model reshaping. Focusing on the impedance model reshaping stage of a grid-type energy storage converter, it clearly presents the introduction of q-axis voltage feedforward control and regulation coefficients. k Subsequently, key electrical signals inside the converter (such as voltage deviation) Inductor current deviation The transmission, calculation, and control logic of the current term directly reflects the offsetting current term. The technical principles behind the negative impacts.

[0061] The signal transmission path is: Signal input stage: based on DC side voltage deviation As a core input signal, this signal reflects the dynamic changes in the converter's operating state. When the steady-state range is exceeded, the subsequent control adjustment process is triggered; Voltage loop signal processing: First, we enter the voltage loop correlation matrix. ,through After the operation, the matrix is ​​inverted using the -1 module. The voltage deviation signal is converted into a signal format suitable for current loop control, realizing the signal conversion from voltage deviation to current control reference. Cooperative operation of reactive power loop and current loop: The converted signal is divided into two paths, one of which is connected to the reactive power loop transfer function. The reshaped steady-state current matrix Perform multiplication operations ( ), quantifying the dynamics of the reactive power loop and the impact of the optimized current matrix on the control signal; another path is connected to the current loop PI controller matrix. Interaction, combined with inductor current deviation Perform proportional-integral adjustment to dynamically correct the control signal; Filtering and Signal Output: The control signal after the above calculations is filtered. The filter removes high-frequency noise and ultimately outputs the signal to the main circuit of the converter to adjust the inductor current. To achieve control over DC side voltage deviation The correction, and at the same time through middle Its negative characteristic cancels out the original current term. The negative impact of this is that it blocks the signal transmission path of low-frequency oscillations.

[0062] The current matrix after introducing the control matrix strategy is: (5) The current matrix elements are from the original state before regulation. Become ,in .

[0063] Here is the control coefficient k >1, at this time The result is negative, thus eliminating the effect caused by The negative impact on stability was significantly suppressed by the interaction behavior between the grid-type energy storage converter and the power grid in the low-frequency band.

[0064] In another embodiment of the present invention, a low-frequency oscillation suppression system for a grid-type energy storage converter is provided. This system can be used to implement the above-mentioned low-frequency oscillation suppression method for a grid-type energy storage converter. Specifically, the low-frequency oscillation suppression system for the grid-type energy storage converter includes an impedance module, a simplification module, and a reshaping module.

[0065] Among them, the impedance module is used to construct the impedance model of the grid-type energy storage converter using the small-signal modeling method, and obtain the small-signal impedance model of the grid-type energy storage converter based on virtual admittance control. Transform the impedance matrix in the dq coordinate system to the stationary coordinate system and perform an impedance transformation. The impedance matrix in the stationary coordinate system... Represented as:

[0066] Impedance matrix of small-signal impedance model of grid-type energy storage converter in synchronous rotating dq coordinate system for:

[0067] Wherein, the synchronization angular frequency is , This represents the frequency offset between the stationary coordinate system and the synchronously rotating dq coordinate system.

[0068] The simplification module reduces the order of the impedance model of the grid-type energy storage converter obtained by the impedance module. During simplification, it retains the key impedance characteristics within the synchronous frequency band, ignores the filter capacitor, active power loop transfer function, current loop decoupling matrix, and filter inductor, and identifies the steady-state current matrix. elements in It is a key factor affecting stability; Identifying key factors includes determining the steady-state current matrix through actual testing and simulation in a weak network environment. elements in The omission of filter capacitors, active power loop transfer function, current loop decoupling matrix, and filter inductor is achieved through model order reduction. The synchronization frequency band is 0.1~10Hz. The simplified impedance model of the grid-type energy storage converter in the dq coordinate system is described. Represented as:

[0069] in, The correlation matrix of the filter inductor. This is the relevant matrix for the current loop PI controller. The reactive power loop related transfer function, This is the voltage loop correlation matrix. This is the voltage steady-state value matrix. This is the current steady-state value matrix. The identity matrix is ​​used. The reshaping module reshapes the impedance model of the grid-type energy storage converter obtained from the simplification module by adding a q-axis voltage feedforward control loop and introducing a regulation coefficient. The current steady-state value matrix elements in Modified to ,in, The preset parameters related to the q-axis voltage feedforward control suppress the interaction behavior between the grid-type energy storage converter and the power grid in the low-frequency band, thereby reducing low-frequency oscillations.

[0070] Current matrix after introducing control matrix strategy Represented as:

[0071] in, The current steady-state value matrix Preset elements in For the modified element; The control coefficient The range of values ​​is , making If the value is negative, the error is eliminated. Negative impact on stability.

[0072] The q-axis voltage feedforward control loop acquires the q-axis output voltage signal of the grid-type energy storage converter in real time, and dynamically adjusts the preset parameters based on the acquired voltage signal. The value of is determined by monitoring the output current fluctuation amplitude of the grid-connected energy storage converter in real time during the process of suppressing the interaction between the grid-connected energy storage converter and the power grid in the low-frequency band. If the fluctuation amplitude exceeds the preset threshold, the control coefficient is increased. The value of .

[0073] This invention provides a terminal device comprising a processor and a memory. The memory stores a computer program, which includes program instructions. The processor executes the program instructions stored in the computer storage medium. The processor may be a Central Processing Unit (CPU), or other general-purpose processors, graphics processing units (GPUs), tensor processing units (TPUs), digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computing and control core of the terminal, suitable for implementing one or more instructions, specifically suitable for loading and executing one or more instructions to achieve a corresponding method flow or function. The processor described in this embodiment can be used in the operation of a low-frequency oscillation suppression method for a grid-type energy storage converter, including: An impedance model of a grid-type energy storage converter is constructed using a small-signal modeling method, resulting in a small-signal impedance model of the grid-type energy storage converter based on virtual admittance control. The obtained impedance model is then simplified by order reduction, preserving its key impedance characteristics within the synchronous frequency band while neglecting the filter capacitor, active power loop transfer function, current loop decoupling matrix, and filter inductor. The steady-state current matrix is ​​then identified. elements in It is a key factor affecting stability; the impedance model of the obtained grid-type energy storage converter is reshaped by adding a q-axis voltage feedforward control loop to the control and introducing a regulation coefficient. The current steady-state value matrix elements in Modified to ,in, The preset parameters related to the q-axis voltage feedforward control suppress the interaction behavior between the grid-type energy storage converter and the power grid in the low-frequency band, thereby reducing low-frequency oscillations.

[0074] Please see Figure 5 The terminal device is a computer device. In this embodiment, the computer device 60 includes a processor 61, a memory 62, and a computer program 63 stored in the memory 62 and executable on the processor 61. When executed by the processor 61, the computer program 63 implements the low-frequency oscillation suppression method for the grid-type energy storage converter in this embodiment. To avoid repetition, these details are not elaborated here. Alternatively, when executed by the processor 61, the computer program 63 implements the functions of each model / unit in the low-frequency oscillation suppression system of the grid-type energy storage converter in this embodiment. To avoid repetition, these details are not elaborated here.

[0075] Computer device 60 can be a desktop computer, laptop, handheld computer, cloud server, or other computing device. Computer device 60 may include, but is not limited to, a processor 61 and a memory 62. Those skilled in the art will understand that... Figure 5 This is merely an example of computer device 60 and does not constitute a limitation on computer device 60. It may include more or fewer components than shown, or combine certain components, or different components. For example, computer device may also include input / output devices, network access devices, buses, etc.

[0076] The processor 61 may be a Central Processing Unit (CPU), or other general-purpose processors, graphics processing units (GPUs), tensor processing units (TPUs), digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0077] The memory 62 can be an internal storage unit of the computer device 60, such as a hard disk or RAM of the computer device 60. The memory 62 can also be an external storage device of the computer device 60, such as a plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, etc., provided on the computer device 60.

[0078] Furthermore, the memory 62 may include both internal storage units of the computer device 60 and external storage devices. The memory 62 is used to store computer programs and other programs and data required by the computer device. The memory 62 can also be used to temporarily store data that has been output or will be output.

[0079] Please see Figure 6 The terminal device is an electronic device 600, which is manifested in the form of a general-purpose computing device. The components of the electronic device may include, but are not limited to: at least one processing unit 610, at least one storage unit 620, a bus 630 connecting different platform components (including storage unit 620 and processing unit 610), a display unit 640, etc.

[0080] The storage unit stores program code, which can be executed by the processing unit 610 to perform the steps described in the method section of this specification according to various exemplary embodiments of the present invention. For example, the processing unit 610 can perform actions such as... Figure 4 The steps are shown in the figure.

[0081] Storage unit 620 may include a readable medium in the form of a volatile storage unit, such as random access memory (RAM) 6201 and / or cache memory 6202, and may further include a read-only memory (ROM) 6203.

[0082] Storage unit 620 may also include a program / utility 6204 having a set (at least one) program module 6205, such program module 6205 including but not limited to: operating system, one or more application programs, other program modules and program data, each or some combination of these examples may include an implementation of a network environment.

[0083] Bus 630 can represent one or more of several types of bus structures, including a memory cell bus or memory cell controller, a peripheral bus, a graphics acceleration port, a processing unit, or a local bus using any of the multiple bus structures.

[0084] Electronic device 600 can also communicate with one or more external devices 700 (e.g., keyboard, pointing device, Bluetooth device, etc.), and with one or more devices that enable a user to interact with electronic device 600, and / or with any device that enables electronic device 600 to communicate with one or more other computing devices (e.g., router, modem). This communication can be performed via input / output interface 650. Furthermore, electronic device 600 can also communicate with one or more networks (e.g., local area network, wide area network, and / or public network, such as the Internet) via network adapter 660. Network adapter 660 can communicate with other modules of electronic device 600 via bus 630. It should be understood that, although not shown in the figures, other hardware and / or software modules can be used in conjunction with electronic device 600, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage platforms.

[0085] Example 4 This invention also provides a storage medium, specifically a computer-readable storage medium, which is a memory device in a terminal device for storing programs and data. It is understood that the computer-readable storage medium here can include both built-in storage media in the terminal device and extended storage media supported by the terminal device; it can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. The computer-readable storage medium provides storage space that stores the terminal's operating system. Furthermore, the storage space also stores one or more instructions suitable for loading and execution by a processor, which can be one or more computer programs (including program code). More specific examples of the computer-readable storage medium include: an electrical connection having one or more wires, a portable disk, a hard disk, random access memory, read-only memory, erasable programmable read-only memory, optical fiber, portable compact disk read-only memory, optical storage device, magnetic storage device, or any suitable combination thereof.

[0086] Computer-readable storage media also include data signals propagated in baseband or as part of a carrier wave, carrying readable program code. Such propagated data signals can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A readable storage medium can also be any readable medium other than a readable storage medium that can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on the readable storage medium can be transmitted using any suitable medium, including but not limited to wireless, wired, optical fiber, radio frequency, etc., or any suitable combination thereof.

[0087] Program code for performing the operations of this invention can be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java and C++, and conventional procedural programming languages ​​such as C or similar languages. The program code can execute entirely on the user's computing device, partially on the user's computing device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server. In cases involving remote computing devices, the remote computing device can be connected to the user's computing device via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0088] One or more instructions stored in a computer-readable storage medium can be loaded and executed by a processor to implement the corresponding steps of the low-frequency oscillation suppression method for grid-type energy storage converters in the above embodiments; one or more instructions in the computer-readable storage medium are loaded and executed by the processor to perform the following steps: An impedance model of a grid-type energy storage converter is constructed using a small-signal modeling method, resulting in a small-signal impedance model of the grid-type energy storage converter based on virtual admittance control. The obtained impedance model is then simplified by order reduction, preserving its key impedance characteristics within the synchronous frequency band while neglecting the filter capacitor, active power loop transfer function, current loop decoupling matrix, and filter inductor. The steady-state current matrix is ​​then identified. elements in It is a key factor affecting stability; the impedance model of the obtained grid-type energy storage converter is reshaped by adding a q-axis voltage feedforward control loop to the control and introducing a regulation coefficient. The current steady-state value matrix elements in Modified to ,in, The preset parameters related to the q-axis voltage feedforward control suppress the interaction behavior between the grid-type energy storage converter and the power grid in the low-frequency band, thereby reducing low-frequency oscillations.

[0089] The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0090] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0091] 1. Simulation experimental data To accurately verify the effectiveness of the technical solution of this invention, a multi-machine parallel simulation system for grid-type energy storage converters based on MATLAB / Simulink was built. The system parameters strictly match the actual engineering scenario, and the specific configuration is as follows: Energy storage converter parameters: 3 2MW grid-connected energy storage converters are connected in parallel, with a switching frequency of 10kHz, DC side voltage of 800V, filter inductor of 2mH, filter capacitor of 50μF, virtual admittance control strategy, current loop PI parameters (kp=0.8, ki=50), voltage loop PI parameters (kp=0.2, ki=10). Power grid parameters: Simulate power grid environments of different strengths: strong grid condition (Short-circuit ratio SCR=5, grid resistance Rg=0.02Ω, grid inductance Lg=0.05H), weak grid condition (Short-circuit ratio SCR=2.5, grid resistance Rg=0.05Ω, grid inductance Lg=0.1H), and extremely weak grid condition (Short-circuit ratio SCR=1.5, grid resistance Rg=0.08Ω, grid inductance Lg=0.15H). Load and disturbance conditions: Set an inductive load (power factor 0.85) to simulate typical operating conditions such as power fluctuations (0-120% rated power step), sudden changes in grid parameters (inductance ±20%, resistance ±30%), and multi-machine start-up and shutdown disturbances (sudden start-up and shutdown of one or two converters).

[0092] (I) Comparison of low-frequency oscillation suppression effects under different power grid strengths For the critical frequency band of 0.1-10Hz, the oscillation amplitude suppression effect of the proposed solution is compared with that of the traditional damping resistor solution and the single-parameter optimization solution. The data are as follows:

[0093] Under different power grid strengths, the solution of this invention can achieve oscillation amplitude suppression of over 82%. Especially under extremely weak grid conditions, traditional solutions suffer from insufficient damping, resulting in oscillation amplitudes as high as 18.7V, while the solution of this invention precisely cancels out the oscillations. The negative impact is that the oscillation amplitude is controlled at 3.2V, which is far superior to other solutions, proving its strong adaptability to complex power grid environments.

[0094] (II) Dynamic response performance test under high power fluctuation conditions The dynamic response of a grid-connected energy storage converter under charging / discharging switching and power step (0→100%→120%→80% rated power) conditions was simulated. The oscillation suppression steady-state time and power fluctuation amplitude were tested, and the data are as follows:

[0095] The present invention uses real-time dynamic adjustment of q-axis voltage feedforward control, which shortens the steady-state time by more than 73.9% compared with the traditional solution, and controls the power fluctuation amplitude within ±6.3%, which is much lower than ±18.7% of the traditional solution. This effectively avoids system protection shutdown caused by drastic power fluctuations and improves the operational stability and reliability of the energy storage system.

[0096] (III) Adaptability test for sudden changes in power grid parameters and multi-machine disturbance conditions Sudden changes in power grid parameters: Simulating a fault scenario where the power grid inductance suddenly increases by 20% and the resistance suddenly increases by 30%, the oscillation suppression effect is tested. When the grid inductance is +20%, the oscillation amplitude of the traditional solution increases sharply to 21.3V, while the solution of this invention only increases to 3.8V, with a suppression effect of 82.2%. When the grid resistance is +30%: the oscillation amplitude of the traditional solution is 19.5V, while that of the present invention is 2.9V, with a suppression effect of 85.1%.

[0097] Multi-machine disturbance: Simulate a disturbance scenario where one of the three parallel converters suddenly shuts down and another restarts. Single unit shutdown disturbance: The traditional solution oscillates for 1.9s with an amplitude of 15.7V; the solution of this invention oscillates for 0.45s with an amplitude of 2.5V. Single-unit restart disturbance: The traditional solution oscillates for 2.1s with an amplitude of 16.3V; the solution of this invention oscillates for 0.5s with an amplitude of 2.7V.

[0098] Analysis: Under extreme conditions such as sudden changes in power grid parameters and multi-machine disturbances, the solution of this invention can still maintain excellent oscillation suppression effect, with short oscillation duration and low amplitude, proving that it has strong robustness and can cope with complex power grid disturbances and equipment operating condition changes in actual engineering.

[0099] (iv) Long-term operational stability test The simulation system was continuously run for 72 hours, and the oscillation amplitude and output voltage harmonic distortion (THD) were recorded at different time periods. The data are as follows:

[0100] During long-term operation, the oscillation amplitude of the present invention remains stable at 1.4-1.6V, and the voltage THD is controlled at 1.3-1.5%, which is far superior to the 5.2-5.7% of the traditional solution. Moreover, there is no performance degradation phenomenon, which proves its long-term operational stability and can meet the needs of actual energy storage power stations for 24-hour uninterrupted operation.

[0101] Through multi-condition and multi-dimensional simulation tests, the proposed solution achieves over 82% suppression of low-frequency oscillation amplitude, reduces steady-state time by over 70%, controls power fluctuation amplitude within ±6.3%, and reduces voltage THD below 1.5% under various grid strength, power fluctuation, and extreme disturbance conditions, significantly outperforming traditional solutions and single-parameter optimization solutions. Furthermore, the solution requires no hardware modifications and can be implemented solely through control strategy optimization, exhibiting advantages such as strong adaptability, high robustness, and long-term stability. It provides an efficient and reliable technical path for low-frequency oscillation suppression in grid-connected energy storage converters.

[0102] In summary, this invention provides a method and system for suppressing low-frequency oscillations in grid-type energy storage converters. Through a core technical path of modeling, simplification, and reshaping, it achieves precise and efficient suppression of low-frequency oscillations in grid-type energy storage converters. By employing small-signal modeling and order reduction simplification, the current term is precisely located. The core cause of oscillation; by using q-axis voltage feedforward control and optimizing the regulation coefficient, By adjusting to a negative value, the low-frequency interactive oscillation path is blocked at its source. In practical applications, this solution can reduce the oscillation amplitude in the 0.1~10Hz frequency band by more than 80%, and control the power fluctuation amplitude in high-power charging and discharging scenarios to within 5%, significantly improving the stability of the energy storage system. Meanwhile, the solution requires no hardware modifications, adapts to different operating conditions, and its dynamic adjustment mechanism ensures robustness in complex scenarios, providing key technical support for the safe and stable operation of power systems after a high proportion of renewable energy is integrated into the grid.

[0103] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0104] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0105] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed in this invention can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0106] In the embodiments provided by this invention, it should be understood that the disclosed devices / terminals and methods can be implemented in other ways. For example, the device / terminal embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0107] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0108] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0109] If the integrated module / unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random-access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. It should be noted that the content included in the computer-readable medium can be appropriately added or removed according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electrical carrier signals and telecommunication signals.

[0110] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus, and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0111] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0112] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0113] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for suppressing low-frequency oscillation of a meshed energy storage converter, characterized in that, The method comprises the following steps: S1, constructing an impedance model of the grid-connected energy storage converter by using a small signal modeling method to obtain a small signal impedance model of the grid-connected energy storage converter based on virtual admittance control; S2, the impedance model of the networked energy storage converter obtained in step S1 is reduced and simplified, the key impedance characteristics of the impedance model in the synchronous frequency band are retained in the simplification process, the filter capacitance, the active loop transfer function, the current loop decoupling matrix and the filter inductance are ignored, and elements in the current steady-state value matrix are identified as key factors affecting stability; S3. The impedance model of the grid-type energy storage converter obtained in step S2 is reshaped by adding a q-axis voltage feedforward control loop to the control system and introducing a regulation coefficient. The current steady-state value matrix elements in Modified to ,in, The preset parameters related to the q-axis voltage feedforward control suppress the interaction behavior between the grid-type energy storage converter and the power grid in the low-frequency band, thereby reducing low-frequency oscillations.

2. The network configuration energy storage converter low-frequency oscillation suppression method according to claim 1, characterized in that, In step S1, the impedance matrix in the d-q coordinate system is converted to the stationary coordinate system and impedance transformation is performed, and the impedance matrix in the stationary coordinate system is expressed as: where the synchronous angular frequency is , represents the frequency offset between the stationary coordinate system and the synchronous rotating d-q coordinate system.

3. The method of claim 2, wherein, Small-signal impedance model of grid-forming energy storage converter in the synchronous rotating d-q frame is: 。 4. The method of claim 1, wherein, In step S2, the impedance simplified model of the grid-connected energy storage converter in the d-q coordinate system is represented as: wherein, is the filter inductance related matrix, is the current loop PI controller related matrix, is the reactive loop related transfer function, is the voltage loop related matrix, is the voltage steady state value matrix, is the current steady state value matrix, is the identity matrix.

5. The method of claim 4, wherein, Identifying key factors includes determining the steady-state current matrix through actual testing and simulation in a weak network environment. elements in Ignoring the filter capacitor, active power loop transfer function, current loop decoupling matrix, and filter inductor is achieved through model order reduction.

6. The method of claim 1, wherein, In step S2, the synchronization frequency band is 0.1-10 Hz.

7. The method of claim 1, wherein, In step S3, the current matrix after introducing the regulatory matrix strategy is represented as: wherein is a preset element in the matrix of steady-state values of currents is a preset element in the matrix of steady-state values of currents is the modified element.

8. The method of claim 7, wherein, The regulation coefficient is in the range , so that is negative, eliminating the negative impact on stability by .

9. The method of claim 1, wherein, In step S3, the q-axis voltage feedforward control link acquires the q-axis output voltage signal of the network-type energy storage converter in real time, and dynamically adjusts the value of the preset parameter according to the acquired voltage signal. the value of the preset parameter.

10. The method of claim 1, wherein, In step S3, during the process of inhibiting the interaction between the grid-forming energy storage converter and the power grid in the low frequency band, the output current fluctuation amplitude of the grid-forming energy storage converter is monitored in real time, and if the fluctuation amplitude exceeds a preset threshold, the value of the regulation coefficient is increased. of the grid-forming energy storage converter is monitored in real time, and if the fluctuation amplitude exceeds a preset threshold, the value of the regulation coefficient is increased. 11.A system for low frequency oscillation suppression of a meshed energy storage converter, characterized in that, The method comprises the following steps: The impedance module is configured to construct an impedance model of the grid-connected energy storage converter by using a small signal modeling method to obtain a small signal impedance model of the grid-connected energy storage converter based on virtual admittance control. The simplified module simplifies the network type energy storage converter impedance model obtained by the impedance module, retains key impedance characteristics in the synchronous frequency band during the simplification process, ignores the filter capacitor, the active loop transfer function, the current loop decoupling matrix and the filter inductor, and identifies elements in the current steady-state value matrix which are key factors affecting stability ; The remodeling module is configured to remodel the networked energy storage converter impedance model obtained by the simplification module, by adding a q-axis voltage feedforward control link in control and introducing a regulation coefficient The element in the current steady-state value matrix is modified to , wherein , wherein is a preset parameter related to the q-axis voltage feedforward control, inhibits the interaction behavior of the networked energy storage converter and the power grid in the low frequency band, and reduces low frequency oscillation.

12. The network-forming energy storage inverter low-frequency oscillation suppression system of claim 11, wherein, In the impedance module, the impedance matrix in the d-q coordinate system is converted to the stationary coordinate system and impedance transformation is performed, and the impedance matrix in the stationary coordinate system is expressed as: Small-signal impedance model of grid-forming energy storage converter in the synchronous rotating d-q frame is: where the synchronous angular frequency is , represents the frequency offset between the stationary coordinate system and the synchronous rotating d-q coordinate system.

13. The network-forming energy storage inverter low-frequency oscillation suppression system of claim 11, wherein, In the simplified module, identifying key factors includes determining the steady-state current matrix through actual testing and simulation in a weak network environment. elements in The omission of filter capacitors, active power loop transfer function, current loop decoupling matrix, and filter inductor is achieved through model order reduction. The synchronization frequency band is 0.1~10Hz. The simplified impedance model of the grid-type energy storage converter in the dq coordinate system is described. Represented as: wherein, is the filter inductance related matrix, is the current loop PI controller related matrix, is the reactive loop related transfer function, is the voltage loop related matrix, is the voltage steady state value matrix, is the current steady state value matrix, is the identity matrix.

14. The network-forming energy storage inverter low-frequency oscillation suppression system of claim 11, wherein, In the remodeling module, the current matrix after introducing the regulatory matrix strategy is represented as: wherein is a matrix of steady-state current values is a preset element in the matrix is a modified element The regulation coefficient is in the range , so that is negative, eliminating the negative impact on stability by .

15. The network-forming energy storage inverter low-frequency oscillation suppression system of claim 11, wherein, In the reshaping module, the q-axis voltage feedforward control link acquires the q-axis output voltage signal of the network-type energy storage converter in real time, and dynamically adjusts the preset parameter according to the acquired voltage signal ; in the process of inhibiting the interaction between the network-type energy storage converter and the power grid in the low frequency band, the output current fluctuation amplitude of the network-type energy storage converter is monitored in real time, and if the fluctuation amplitude exceeds the preset threshold, the value of the regulation coefficient is increased.

16. A computer-readable storage medium storing one or more programs, the one or more programs comprising instructions for: The one or more programs include instructions that, when executed by a computing device, cause the computing device to perform the method of any one of claims 1-10.

17. A computing device, comprising: The one or more processors, the memory, and the one or more programs are configured to perform the method of any one of claims 1-10. ​

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