Method for evaluating and enhancing stability of power decoupling control of network construction converter

Abstract

The invention discloses a power decoupling control stability evaluation and enhancement method for a network construction converter, and belongs to the technical field of new energy power generation, and the method comprises the steps: collecting the output voltage, current and line parameters of the converter; calculating dq-axis voltage, current and output power through coordinate transformation; output frequency, voltage, power angle and power grid voltage are obtained through droop control; constructing an output power response matrix and calculating a power angle motion state feedback factor G delta; the stability of the system is judged on line according to the value of the G delta, when the G delta tends to an unstable boundary, virtual impedance is introduced into the system to improve the equivalent resistance-inductance ratio of a transmission line, and an output power response matrix is corrected; and finally generating a voltage reference value based on the corrected model. According to the method, the stability margin can be evaluated on line in real time, the stability of the system is enhanced by correcting the virtual impedance, meanwhile, the power decoupling control effect is not affected, and the problem that the stability and the decoupling performance are difficult to consider at the same time is solved.

Description

Technical Field

[0001] This invention belongs to the field of grid-connected control technology for new energy power generation, specifically relating to a method for evaluating and enhancing the stability of power decoupling control in grid-connected converters. Background Technology

[0002] With the global energy shortage and the increasingly severe problem of climate change, the proportion of renewable energy generation in the power system has increased significantly, leading to a decrease in the inertia and damping level of the power system and a decline in its disturbance rejection capability. Grid-based control technology, by simulating the droop characteristics and rotor motion equations of synchronous machines, can autonomously provide inertia, damping, voltage, and frequency support to the power grid, becoming a research frontier and hot topic in renewable energy grid connection technology. However, grid-connected systems using grid-based control technology can experience severe coupling between active and reactive power control when line impedance is relatively high or the power angle is large.

[0003] To eliminate the effects of power coupling characteristics, a power decoupling strategy is usually added to the control loop of the grid converter. However, this will change the original grid converter control structure and introduce new poles and zeros into the system model, thereby bringing new system instability factors. In severe cases, it may cause system oscillation and failure shutdown, degrading the reliability of power supply.

[0004] There are two main strategies for stability analysis of the control loop of a grid-connected converter: the eigenvalue method and the Nyquist criterion. Both methods require establishing the closed-loop transfer function of the grid-connected converter control loop. The eigenvalue method solves for the eigenvalues ​​of the characteristic equation of the closed-loop transfer function and determines stability by the position of the eigenvalues ​​in the root plane. The Nyquist criterion, on the other hand, plots the Nyquist curve of the closed-loop transfer function and determines stability by the relationship between the Nyquist curve and the point (-1, j0). Both are commonly used stability assessment methods in automatic control principles. Their advantage is that they can be used for stability analysis of all objects analyzed in classical control theory. However, their disadvantage is that the computational complexity is limited by the complexity of the analyzed object's model, making them difficult to use for online stability assessment in complex systems.

[0005] Existing strategies for enhancing the stability of decoupling control in grid-connected converters primarily rely on virtual impedance methods. These methods generate virtual inductors or resistors in the control loop to rationally adjust system inertia and damping, thereby improving system stability margin. However, these are all offline design methods and cannot promptly address stability issues arising from sudden changes in operating conditions during system operation. Furthermore, the introduction of virtual impedance alters the controlled object model, thus degrading the decoupling effect of the original power decoupling strategy. Summary of the Invention

[0006] The technical problem to be solved by this invention is to address the shortcomings of the prior art by providing a method for evaluating and enhancing the stability of grid-connected converter power decoupling control. This method evaluates the stability margin of grid-connected converters using power decoupling strategies online and extends their stable operating range through virtual impedance. This addresses the technical problem that existing stability evaluation methods for grid-connected converter power decoupling control require the establishment of a closed-loop transfer function, resulting in large computational loads and complex operations, making it difficult to meet the online evaluation needs of dynamic operation of new energy grid-connected systems.

[0007] The present invention adopts the following technical solution: A method for evaluating and enhancing the stability of power decoupling control in a grid-connected converter includes the following steps: S1. Collect the output voltage and current of the grid-connected converter, as well as the equivalent resistance of the transmission line between the grid-connected converter and the power grid. R g and equivalent inductance L g ; S2. Based on the output voltage and output current acquired in step S1, calculate the output voltage of the grid converter in the dq coordinate system through a rotating coordinate transformation. v odq and output current i odq ; S3. Based on the output voltage obtained in step S2 v odq and output current i odq Calculate the output active power of the grid converter. P and reactive power Q ; S4. Calculate the output active power in step S3. reactive power After subtracting from the active power command and reactive power command respectively, the output angular frequency of the grid converter is calculated through droop control. and output voltage ; S5, Equivalent resistance based on transmission line R g Equivalent inductance L g and the output active power of the grid converter. P Output reactive power Q Output angular frequency ω and output voltage V o Calculate the output power angle of the grid converter. δ v and grid voltage V g ; S6. Based on the obtained transmission line equivalent parameters and output voltage... V o Output power angle δ v and grid voltage V g Construct the output power response matrix of the grid converter; S7. Based on the output power response matrix from step S6, calculate the power angle motion state feedback factor of the amplitude-phase motion equation. G δ ; S8. Based on the feedback factor of the motion state of the power angle obtained in step S7 G δ To determine the system stability of the power decoupling control of the grid converter; S9. If step S8 determines that the system is close to the instability boundary, introduce a virtual impedance into the system. R v And correct the grid converter output power response matrix in step S6; S10. Based on the output power response matrix corrected in step S9, generate the grid converter output voltage reference value. v * oabc It is used for voltage and current dual closed-loop control of grid converters.

[0008] Preferably, in step S1, the output voltage of the grid converter is acquired by a voltage sensor. v oabc The output current of the grid converter is collected by a current sensor. i oabc Equivalent resistance of transmission lines R g and equivalent inductance L g It is calculated based on the design planning data of the line laying type and laying distance.

[0009] Preferably, in step S2, the work angle used for the coordinate transformation is... δ' v The output voltage is obtained synchronously from the stability judgment process in step S8. v odq and output current i odq It is calculated using the coordinate transformation formula.

[0010] Preferably, in step S3, the active power is output. P and reactive power Q The calculation formula is:

[0011] in, for dq Output voltage in coordinate system d Axial components, for dq Output voltage in coordinate system q Axial components, for dq Output current in coordinate system d Axial components, for dq Output current in coordinate system q Axial components.

[0012] Preferably, in step S4, the output angular frequency and voltage V o The calculation formula is:

[0013] in, and These are the rated output angular frequency and voltage of the grid converter, respectively. and These are the active power and reactive power output commands for the grid converter, respectively. and These are the droop coefficients for the active power loop and the reactive power loop, respectively. and ω q These are the cutoff frequencies of the low-pass filters for the active power loop and the reactive power loop, respectively. s For the Laplace operator.

[0014] Preferably, in step S7, the work angle motion state feedback factor It is obtained by calculating the relevant parameters in the output power response matrix. The specific calculation formula is as follows:

[0015] in, H Pδ ( s Let be the transfer function from the power angle to the active power. H PV ( s () is the transfer function from output voltage amplitude to active power. H Qδ ( s () is the transfer function from power angle to reactive power. H QV ( s ) is the transfer function from output voltage amplitude to reactive power.

[0016] Preferably, in step S8, the rule for judging system stability is: when -1 < G δ When < 0, the system converges and operates stably; when G δ >0 or G δ When the value is less than -1, the system diverges and cannot operate stably.

[0017] Preferably, in step S9, the virtual impedance R v The introduction of virtual impedance is used to improve the equivalent impedance-to-inductance ratio of transmission lines. R v The value is determined based on the work angle motion state feedback factor. G δ The difference from the stable boundary is determined.

[0018] Preferably, in step S10, the grid converter output voltage reference value v * oabc By using the corrected output power response matrix, combined with dq The inverse transformation from the coordinate system to the abc coordinate system is used to generate the converter modulation wave.

[0019] Secondly, embodiments of the present invention provide a system for evaluating and enhancing the stability of power decoupling control in a grid-connected converter, comprising: The data acquisition module collects the output voltage and current of the grid-connected converter, as well as the equivalent resistance of the transmission line between the grid-connected converter and the power grid. R g and equivalent inductance L g ; The coordinate transformation module is connected to the acquisition module, receives the output voltage and current from the acquisition module, and calculates the output voltage and current through rotational coordinate transformation. dq Output voltage of grid converter in coordinate system v odq and output current i odq ; The power calculation module, connected to the coordinate transformation module, is used to receive the output voltage. v odq and output current i odq Calculate the output active power of the grid converter. P and reactive power Q ; The droop control module, connected to the parameter acquisition module, power calculation module, and droop control module, is used to receive the output active power. P reactive powerQ After subtracting from the active power command and reactive power command respectively, the output angular frequency of the grid converter is calculated through droop control. ω and output voltage V o ; The power angle and grid voltage calculation module is connected to the parameter acquisition module, power calculation module, and droop control module, and is used to receive the equivalent resistance of the transmission line. R g Equivalent inductance L g and the output active power of the grid converter. P Output reactive power Q The obtained output angular frequency ω and output voltage V o Calculate the output power angle of the grid converter. δ v and grid voltage V g ; The power response matrix construction module is connected to the acquisition module, power angle and grid voltage calculation module respectively, and is used to receive transmission line equivalent parameters and output voltage. V o Output power angle δ v and grid voltage V g Construct the output power response matrix of the grid converter; The feedback factor calculation module, signal-connected to the power response matrix construction module, is used to receive the output power response matrix and calculate the power angle motion state feedback factor of the amplitude and phase motion equations. G δ ; The stability assessment module is signal-connected to the feedback factor calculation module and is used to receive the power angle motion state feedback factor. G δ To determine system stability; The virtual impedance introduction and matrix correction module is connected to the stability judgment module and the power response matrix construction module, respectively, and is used to introduce virtual impedance when the system approaches the instability boundary. R v And correct the output power response matrix; The voltage reference value generation module, connected to the virtual impedance introduction and matrix correction module, receives the corrected output power response matrix and generates the output voltage reference value of the grid converter. v * oabc .

[0020] 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 executes the computer program to implement the steps of the above-described grid converter power decoupling control stability assessment and enhancement method.

[0021] 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 evaluating and enhancing the stability of power decoupling control of grid-connected converters.

[0022] 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 grid converter power decoupling control stability assessment and enhancement method.

[0023] In a sixth aspect, embodiments of the present invention provide an electronic device including a computer program, which, when executed by the electronic device, implements the steps of the above-described method for evaluating and enhancing the stability of power decoupling control of grid-connected converters.

[0024] Compared with the prior art, the present invention has at least the following beneficial effects: A method for evaluating and enhancing the stability of power decoupling control in grid-connected converters, using real-time calculated power angle motion state feedback factors. G δ This approach performs stability assessments, replacing traditional, complex offline analysis methods that rely on closed-loop transfer function eigenvalues ​​or Nyquist curves, significantly reducing the computational burden on the online system. Simultaneously, it integrates stability evaluation with enhancement mechanisms: when the system approaches instability, a virtual impedance is introduced, and the system's output power response model is simultaneously corrected, ensuring that the stability margin is improved without sacrificing the original power decoupling control performance. This resolves the inherent contradiction in existing technologies where the virtual impedance method is mismatched with the decoupling controller design, leading to degraded decoupling effects.

[0025] Furthermore, by acquiring electrical quantities using standard sensors and obtaining parameters using pre-set circuit design data, the reliability and feasibility of the method's foundation are ensured. The evaluation method does not rely on complex online parameter identification techniques, reducing system complexity and cost, making this invention easier to deploy and apply in practical engineering projects.

[0026] Furthermore, the calculation process for the work angle, upon which stability judgment depends, itself relies on the stable operating state of the system. This design ensures the self-consistency and inherent consistency of the entire control logic, enabling stability assessment to be based on the latest real-time state of the system, thus improving the accuracy and timeliness of the assessment.

[0027] Furthermore, by employing mature power calculation theory, the calculation process is simple and efficient, making it highly suitable for implementation in digital controllers. This provides accurate and rapid power feedback information for subsequent stability assessment and control, serving as a crucial foundation for the rapid execution of the entire online evaluation process.

[0028] Furthermore, by introducing a low-pass filter, high-frequency components caused by switching noise and measurement interference in power calculation are effectively filtered out, providing a smooth and reliable power signal for the stability evaluation module, preventing misjudgment, and improving the anti-interference capability of the entire system and the reliability of the evaluation results.

[0029] Furthermore, G δ As a comprehensive criterion derived from the system model, it can profoundly reflect the essential characteristics of the amplitude and phase motion within the system. System stability can be intuitively determined using this single scalar without needing to analyze the entire eigenvalue distribution or the Nyquist curve, greatly simplifying the complexity of online stability analysis and serving as the theoretical foundation for real-time evaluation.

[0030] Furthermore, the control program can be easily controlled by making judgments. G δ The system quickly makes decisions based on whether the value is in the (-1, 0) interval. The logic is simple and the judgment is fast, making it very suitable for implementation in microprocessors through conditional statements, thus ensuring the real-time performance of online evaluation.

[0031] Furthermore, the system introduces virtual impedance only when insufficient stability margin is detected, avoiding unnecessary voltage drops or performance impacts caused by introducing it under stable operating conditions. Simultaneously, by adjusting the equivalent resistance-to-inductance ratio, a key parameter affecting stability, the system's dynamic performance is fundamentally improved.

[0032] Furthermore, this ensures that even with the addition of virtual impedance to enhance stability, the design basis of the subsequent power decoupling controller is updated synchronously. This allows the decoupling control to always accurately compensate for the current real controlled object model, thereby perfectly maintaining excellent power decoupling performance while widening the stable operating range.

[0033] 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.

[0034] In summary, this invention, by constructing a closed-loop control framework of online evaluation, real-time judgment, dynamic enhancement, and model correction, innovatively solves the industry problem of balancing stability and decoupling performance in the power decoupling control of grid-connected converters. It achieves online improvement of stability margin without sacrificing dynamic performance, is computationally simple, and is suitable for engineering applications.

[0035] 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

[0036] Figure 1 A schematic diagram of a power decoupling control method for grid-connected converters; Figure 2 Diagram of the small-signal model of the output power response of a grid converter; Figure 3 Diagram of a small-signal model for power decoupling control of a grid converter; Figure 4 This is a schematic diagram of the experimental platform; Figure 5 Figure showing the experimental results of power decoupling control instability; Figure 6 The figure shows the experimental results of power decoupling control stability after adding virtual impedance; Figure 7 Figure showing the experimental results of adding traditional virtual impedance power decoupling; Figure 8 Figure showing the experimental results of adding modified virtual impedance power decoupling; Figure 9 A schematic diagram of a computer device provided in an embodiment of the present invention; Figure 10 This is a block diagram of a chip provided according to an embodiment of the present invention.

[0037] 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

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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)."

[0044] 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.

[0045] This invention provides a method for evaluating and enhancing the stability of power decoupling control in grid-connected converters. The method involves collecting the output voltage and current of the grid-connected converter and feeding them to the controller. The active and reactive power outputs are calculated, and the difference between the calculated results and the active and reactive power commands is fed into the droop controller to obtain the grid-connected converter output voltage, power angle, and grid voltage. Based on the above calculations, the power angle motion state feedback factor in the amplitude-phase motion equation is calculated. Its gain allows for online evaluation of whether the power decoupling control of the grid-connected converter can operate stably. If the system is close to the instability boundary, a modified virtual impedance is introduced to improve the equivalent impedance-inductance ratio of the transmission line, thereby increasing the system's stability margin without affecting the decoupling control effect.

[0046] Example 1 Please see Figure 1 The present invention discloses a method for evaluating and enhancing the stability of power decoupling control in a grid-connected converter, comprising the following steps: S1. Acquire the output voltage of the grid converter through voltage and current sensors. v oabc and output current i oabc Measuring the equivalent resistance of the transmission line between the grid converter and the power grid. R g and equivalent inductance L g ; Equivalent inductance of transmission line L g and resistance R g It can be calculated from the design planning data such as the model and laying distance selected during the line laying.

[0047] S2. Based on the output voltage and output current acquired in step S1, calculate using a rotating coordinate transformation. dq Output voltage of grid converter in coordinate system v odq and output current i odq ; Perform rotation coordinate transformation calculations dq Output voltage of grid converter in coordinate system v odq and output current i odq The working angle used at that time δ' v The output voltage is calculated from step S8. v odq and output current i odq The calculation is as follows:

[0048]

[0049] in, for dq Output voltage in coordinate system d Axial components, for dq Output voltage in coordinate system q Axial components, for dq Output current in coordinate system d Axial components, for dq Output current in coordinate system q Axial components.

[0050] S3. Based on the output voltage obtained in step S2 v odq and output current i odq Calculate the output active power of the grid converter P and reactive power Q ; Active power P and reactive power Q The calculation is as follows:

[0051] S4. Calculate the output active power in step S3. P and reactive power Q After subtracting from the active power command and reactive power command respectively, the output angular frequency of the grid converter is calculated through droop control. ω and voltage V o ; angular frequency and voltage V o The calculation is as follows:

[0052] in, and These are the rated output angular frequency and voltage of the grid converter, respectively. and These are the active power and reactive power output commands for the grid converter, respectively. and These are the droop coefficients for the active power loop and the reactive power loop, respectively. and ω q These are the cutoff frequencies of the low-pass filters for the active power loop and the reactive power loop, respectively. sFor the Laplace operator.

[0053] S5, Equivalent resistance based on transmission line R g Equivalent inductance L g and the output active power of the grid converter. P Output reactive power Q The output angular frequency obtained in step S4 ω and output voltage V o Calculate the output power angle of the grid converter δ v and grid voltage V g ; Output power angle δ v and grid voltage V g The calculation is as follows:

[0054]

[0055] S6. Based on the transmission line equivalent parameters of step S1 and the output voltage of step S4... V o Output power angle in step S5 δ v and grid voltage V g Calculate the output power response matrix of the grid converter; The small-signal model corresponding to the output power response matrix of the grid converter is as follows: Figure 2 As shown, the output power response matrix is ​​calculated as follows:

[0056]

[0057]

[0058]

[0059]

[0060] in, H Pδ ( s Let be the transfer function from the power angle to the active power. H PV ( s () is the transfer function from output voltage amplitude to active power. H Qδ( s () is the transfer function from power angle to reactive power. H QV ( s () is the transfer function from output voltage amplitude to reactive power. s For the Laplace operator.

[0061] S7. Based on the output power response matrix from step S6, calculate the power angle motion state feedback factor of the amplitude-phase motion equation. G δ ; Work angle motion state feedback factor G δ The calculation is as follows:

[0062] S8. Based on the amplitude and phase motion equations, trajectory, and motion state feedback factor of the power angle. G δ Determine system stability;

[0063] When -1 < G δ When < 0, the system converges and can operate stably; while when G δ >0 or G δ When the value is less than -1, the system diverges towards infinity and cannot operate stably.

[0064] The stability assessment process is conducted online in real time and runs in the grid converter controller, just like other steps.

[0065] S9, when the motion state feedback factor of the work angle G δ When operating towards the unstable boundary, add an appropriate virtual impedance to the system. R v The feedback factor of the power angle motion state is constrained by improving the equivalent impedance-inductance ratio of the system transmission line. G δ scope;

[0066] in, Voltage reference value d Axial components, Voltage reference value q Axial components. R vdd Virtual impedance d Axial components, R vqq Virtual impedance q Axial components,R vdq and R vqd Virtual impedance dq Axial coupling component.

[0067] S10. Correct the output power response matrix of the grid converter after adding virtual impedance in step S6;

[0068]

[0069]

[0070]

[0071] in, For the revised version H Pδ ( s ), For the revised version H PV ( s ), For the revised version H Qδ ( s ), For the revised version H QV ( s ), s For the Laplace operator.

[0072] S11. Calculate the reference value of the output voltage of the grid-connected converter. v * oabc .

[0073] The generated grid-connected converter output voltage reference is used to generate the modulation wave for the converter's voltage and current dual closed-loop control. (Grid-connected converter output voltage reference value) v * oabc The calculation is as follows:

[0074] in, , , Output voltage reference value v * oabc The abc phase value.

[0075] Example 2 In another embodiment of the present invention, a system for evaluating and enhancing the stability of power decoupling control of a grid-connected converter is provided. This system can be used to implement the above-mentioned method for evaluating and enhancing the stability of power decoupling control of a grid-connected converter. Specifically, the system includes an acquisition module, a coordinate transformation module, a power calculation module, a droop control module, a power angle and grid voltage calculation module, a power response matrix construction module, a feedback factor calculation module, a stability judgment module, a virtual impedance introduction and matrix correction module, and a voltage reference value generation module.

[0076] The data acquisition module collects the output voltage and current of the grid-connected converter, as well as the equivalent resistance of the transmission line between the grid-connected converter and the power grid. R g and equivalent inductance L g ; The coordinate transformation module is connected to the acquisition module, receives the output voltage and current from the acquisition module, and calculates the output voltage and current through rotational coordinate transformation. dq Output voltage of grid converter in coordinate system v odq and output current i odq ; The power calculation module, connected to the coordinate transformation module, is used to receive the output voltage. v odq and output current i odq Calculate the output active power of the grid converter. P and reactive power Q ; The droop control module, connected to the parameter acquisition module, power calculation module, and droop control module, is used to receive the output active power. P reactive power Q After subtracting from the active power command and reactive power command respectively, the output angular frequency of the grid converter is calculated through droop control. ω and output voltage V o ; The power angle and grid voltage calculation module, connected to the parameter acquisition module, power calculation module, and droop control module, is used to receive the equivalent resistance of the transmission line. R g Equivalent inductance L g and the output active power of the grid converter. P Output reactive power Q The obtained output angular frequency ω and output voltage V oCalculate the output power angle of the grid converter. δ v and grid voltage V g ; The power response matrix construction module is connected to the acquisition module, power angle and grid voltage calculation module respectively, and is used to receive transmission line equivalent parameters and output voltage. V o Output power angle δ v and grid voltage V g Construct the output power response matrix of the grid converter; The feedback factor calculation module, signal-connected to the power response matrix construction module, is used to receive the output power response matrix and calculate the power angle motion state feedback factor of the amplitude and phase motion equations. G δ ; The stability assessment module is signal-connected to the feedback factor calculation module and is used to receive the power angle motion state feedback factor. G δ To determine system stability; The virtual impedance introduction and matrix correction module is connected to the stability judgment module and the power response matrix construction module, respectively, and is used to introduce virtual impedance when the system approaches the instability boundary. R v And correct the output power response matrix; The voltage reference value generation module, connected to the virtual impedance introduction and matrix correction module, receives the corrected output power response matrix and generates the output voltage reference value of the grid converter. v * oabc .

[0077] Example 3 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 corresponding method flows or corresponding functions. The processor described in this embodiment can be used in the operation of a grid-connected converter power decoupling control stability assessment and enhancement method, including: Collect the output voltage and current of the grid-connected converter, as well as the equivalent resistance of the transmission line between the grid-connected converter and the power grid. R g and equivalent inductance L g Based on the collected output voltage and output current, the output voltage of the grid converter in the dq coordinate system is calculated through a rotating coordinate transformation. v odq and output current i odq Based on the obtained output voltage v odq and output current i odq Calculate the output active power of the grid converter. P and reactive power Q The calculated output active power P and reactive power Q After subtracting from the active power command and reactive power command respectively, the output angular frequency of the grid converter is calculated through droop control. ω and output voltage V o Based on the equivalent resistance of the transmission line R g Equivalent inductance L gand the output active power of the grid converter. P Output reactive power Q Output angular frequency ω and output voltage V o Calculate the output power angle of the grid converter. δ v and grid voltage V g Based on the equivalent parameters of the transmission line and the output voltage V o Output power angle δ v and grid voltage V g Construct the output power response matrix of the grid converter; based on the output power response matrix, calculate the power angle motion state feedback factor of the amplitude-phase motion equation. G δ Based on the obtained work angle motion state feedback factor G δ Determine the system stability of the grid converter power decoupling control; if the system is determined to be close to the instability boundary, introduce virtual impedance into the system. R v The output power response matrix of the grid-connected converter is then corrected; based on the corrected output power response matrix, a reference value for the output voltage of the grid-connected converter is generated. v * oabc It is used for voltage and current dual closed-loop control of grid converters.

[0078] Please see Figure 9 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 grid-connected converter power decoupling control stability assessment and enhancement method described 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 grid-connected converter power decoupling control stability assessment and enhancement system described in this embodiment. To avoid repetition, these details are not elaborated here.

[0079] 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 9This 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.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] Please see Figure 10 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.

[0084] 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 1 The steps are shown in the figure.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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 with 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.

[0090] 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.

[0091] 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).

[0092] 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 grid converter power decoupling control stability assessment and enhancement method 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: Collect the output voltage and current of the grid-connected converter, as well as the equivalent resistance of the transmission line between the grid-connected converter and the power grid. R g and equivalent inductance L g Based on the collected output voltage and output current, the output voltage of the grid converter in the dq coordinate system is calculated through a rotating coordinate transformation. v odq and output current i odq Based on the obtained output voltage v odq and output current i odq Calculate the output active power of the grid converter. P and reactive power Q The calculated output active power P and reactive power Q After subtracting from the active power command and reactive power command respectively, the output angular frequency of the grid converter is calculated through droop control. ω and output voltage V o Based on the equivalent resistance of the transmission line R g Equivalent inductance L g and the output active power of the grid converter. P Output reactive power Q Output angular frequency ω and output voltage V o Calculate the output power angle of the grid converter. δ v and grid voltage V g Based on the equivalent parameters of the transmission line and the output voltage V o Output power angle δ v and grid voltage V g Construct the output power response matrix of the grid converter; based on the output power response matrix, calculate the power angle motion state feedback factor of the amplitude-phase motion equation. G δ Based on the obtained work angle motion state feedback factor Gδ Determine the system stability of the grid converter power decoupling control; if the system is determined to be close to the instability boundary, introduce virtual impedance into the system. R v The output power response matrix of the grid-connected converter is then corrected; based on the corrected output power response matrix, a reference value for the output voltage of the grid-connected converter is generated. v * oabc It is used for voltage and current dual closed-loop control of grid converters.

[0093] 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.

[0094] 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.

[0095] Please see Figure 5 Table 1 shows a schematic diagram of a grid-connected converter experimental platform built according to the present invention. The main system parameters used in the experiment are shown in Table 1. The experimental platform uses a TMS320F28377 as the main controller, an ITECH IT6006C as the DC source, and an ITECH IT7909 to simulate the power grid. The grid voltage, grid-connected converter output voltage, and output current are observed using an oscilloscope. The host computer collects the status information of the controller through SCI communication.

[0096] Table 1 Main System Parameters

[0097] To verify the effectiveness of this invention, a small-signal model for power decoupling control is selected as follows: Figure 3 As shown. Figure 5To illustrate the experimental results when the proposed online stability evaluation strategy for power decoupling control was incorporated but without virtual impedance enhancement, power decoupling control was initiated at 0.4s. The power angle motion state feedback factor was calculated online at this time. G δ =-2.5403, the system is unstable. It can be seen that the system oscillates and diverges, eventually triggering a protection shutdown at 0.8s. Figure 6 To incorporate the online stability evaluation strategy for power decoupling control proposed in this invention and the experimental results when virtual impedance is added to enhance stability, power decoupling control is initiated at 0.4s. At this time, the power angle motion state feedback factor is calculated online. G δ =-0.9118, the system is stable, and it can be seen that the system is running normally.

[0098] Figure 7 and Figure 8 The effects of adding traditional virtual impedance to enhance stability and adding the modified virtual impedance proposed in this invention on the decoupling control effect were compared. The initial value of the power command for both operating conditions was set to... P ref =5kW, Q ref =5kVar; P ref Increase by 2kW at 2s and decrease by 2kW at 4s. Q ref Adding 2kVar at 6s and decreasing it by 2kVar at 8s reveals that while both methods enhance the stable operating range of the decoupling control method in this example, the introduction of virtual impedance alters the original controlled object model, preventing the decoupling controller designed according to step S6 from completely eliminating the power coupling term in step S10. This results in dynamic and static coupling between active and reactive power. However, using the grid converter power response model modified with virtual impedance for decoupling control design yields the following output power experimental results: Figure 8 As shown, the dynamic and static coupling between active power and reactive power is basically eliminated at this time, resulting in a better decoupling effect.

[0099] In summary, the present invention provides a method for evaluating and enhancing the stability of power decoupling control in grid-connected converters. For online evaluation of the stability of power decoupling control in grid-connected converters, the power angle motion state feedback factor calculated in step S8 is used. G δGain can be determined online without solving the closed-loop transfer function characteristic equation or plotting the root locus curve (both of which are quite complex when online). Regarding the stability enhancement strategy for power decoupling control using virtual impedance, modifying the output power response matrix of the grid converter after introducing virtual impedance, and designing the power decoupling control of the grid converter based on the modified model, can guarantee the power decoupling effect. Otherwise, the addition of virtual impedance to enhance stability will lead to a deterioration in the power decoupling effect.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] 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.

[0108] 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.

[0109] 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.

[0110] 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 evaluating and enhancing the stability of power decoupling control in a grid-connected converter, characterized in that, Includes the following steps: S1. Collect the output voltage and current of the grid-connected converter, as well as the equivalent resistance of the transmission line between the grid-connected converter and the power grid. R g and equivalent inductance L g ; S2. Based on the output voltage and output current acquired in step S1, calculate using a rotating coordinate transformation. dq Output voltage of grid converter in coordinate system v odq and output current i odq ; S3. Based on the output voltage obtained in step S2 v odq and output current i odq Calculate the output active power of the grid converter. P and reactive power Q ; S4. Calculate the output active power in step S3. P and reactive power Q After subtracting from the active power command and reactive power command respectively, the output angular frequency of the grid converter is calculated through droop control. ω and output voltage V o ; S5, Equivalent resistance based on transmission line R g Equivalent inductance L g and the output active power of the grid converter. P Output reactive power Q Output angular frequency ω and output voltage V o Calculate the output power angle of the grid converter. δ v and grid voltage V g ; S6. Based on the obtained transmission line equivalent parameters and output voltage... V o Output power angle δ v and grid voltage V g Construct the output power response matrix of the grid converter; S7. Based on the output power response matrix from step S6, calculate the power angle motion state feedback factor of the amplitude-phase motion equation. G δ ; S8. Based on the feedback factor of the motion state of the power angle obtained in step S7 G δ To determine the system stability of the power decoupling control of the grid converter; S9. If step S8 determines that the system is close to the instability boundary, introduce a virtual impedance into the system. R v And correct the grid converter output power response matrix in step S6; S10. Based on the output power response matrix corrected in step S9, generate the grid converter output voltage reference value. v * oabc It is used for voltage and current dual closed-loop control of grid converters.

2. The method for evaluating and enhancing the stability of power decoupling control in a grid-connected converter according to claim 1, characterized in that, In step S1, the output voltage of the grid converter is acquired by a voltage sensor. v oabc The output current of the grid converter is collected by a current sensor. i oabc Equivalent resistance of transmission lines R g and equivalent inductance L g It is calculated based on the design planning data of the line laying type and laying distance.

3. The method for evaluating and enhancing the stability of power decoupling control in a grid-connected converter according to claim 1, characterized in that, In step S2, the angle of rotation used for coordinate transformation δ' v The output voltage is obtained synchronously from the stability judgment process in step S8. v odq and output current i odq It is calculated using the coordinate transformation formula.

4. The method for evaluating and enhancing the stability of power decoupling control in a grid-connected converter according to claim 1, characterized in that, In step S3, the active power is output. P and reactive power Q The calculation formula is: in, for dq Output voltage in coordinate system d Axial components, for dq Output voltage in coordinate system q Axial components, for dq Output current in coordinate system d Axial components, for dq Output current in coordinate system q Axial components.

5. The method for evaluating and enhancing the stability of power decoupling control in a grid-connected converter according to claim 1, characterized in that, In step S4, the output angular frequency is... and voltage V o The calculation formula is: in, and These are the rated output angular frequency and voltage of the grid converter, respectively. and These are the active power and reactive power output commands for the grid converter, respectively. and These are the droop coefficients for the active power loop and the reactive power loop, respectively. and ω q These are the cutoff frequencies of the low-pass filters for the active power loop and the reactive power loop, respectively. s For the Laplace operator.

6. The method for evaluating and enhancing the stability of power decoupling control in a grid-connected converter according to claim 1, characterized in that, In step S7, the work angle motion state feedback factor G δ It is obtained by calculating the relevant parameters in the output power response matrix. The specific calculation formula is as follows: in, H Pδ ( s Let be the transfer function from the power angle to the active power. H PV ( s () is the transfer function from output voltage amplitude to active power. H Qδ ( s () is the transfer function from power angle to reactive power. H QV ( s ) is the transfer function from output voltage amplitude to reactive power.

7. The method for evaluating and enhancing the stability of power decoupling control in a grid-connected converter according to claim 1, characterized in that, In step S8, the rule for judging system stability is: when -1 < G δ When <0, the system converges and operates stably; when G δ >0 or G δ When the value is less than -1, the system diverges and cannot operate stably.

8. The method for evaluating and enhancing the stability of power decoupling control in a grid-connected converter according to claim 1, characterized in that, In step S9, virtual impedance R v The introduction of virtual impedance is used to improve the equivalent impedance-to-inductance ratio of transmission lines. R v The value is determined based on the work angle motion state feedback factor. G δ The difference from the stable boundary is determined.

9. The method for evaluating and enhancing the stability of power decoupling control in a grid-connected converter according to claim 1, characterized in that, In step S10, the reference value of the grid converter output voltage is... v * oabc By using the corrected output power response matrix, combined with dq The inverse transformation from the coordinate system to the abc coordinate system is used to generate the converter modulation wave.

10. A system for evaluating and enhancing the stability of power decoupling control in a grid-connected converter, characterized in that, include: The data acquisition module collects the output voltage and current of the grid-connected converter, as well as the equivalent resistance of the transmission line between the grid-connected converter and the power grid. R g and equivalent inductance L g ; The coordinate transformation module is connected to the acquisition module, receives the output voltage and current from the acquisition module, and calculates the output voltage and current through rotational coordinate transformation. dq Output voltage of grid converter in coordinate system v odq and output current i odq ; The power calculation module, connected to the coordinate transformation module, is used to receive the output voltage. v odq and output current i odq Calculate the output active power of the grid converter. P and reactive power Q ; The droop control module, connected to the parameter acquisition module, power calculation module, and droop control module, is used to receive the output active power. P reactive power Q After subtracting from the active power command and reactive power command respectively, the output angular frequency of the grid converter is calculated through droop control. ω and output voltage V o ; The power angle and grid voltage calculation module, connected to the parameter acquisition module, power calculation module, and droop control module, is used to receive the equivalent resistance of the transmission line. R g Equivalent inductance L g and the output active power of the grid converter. P Output reactive power Q The obtained output angular frequency ω and output voltage V o Calculate the output power angle of the grid converter. δ v and grid voltage V g ; The power response matrix construction module is connected to the acquisition module, power angle and grid voltage calculation module respectively, and is used to receive transmission line equivalent parameters and output voltage. V o Output power angle δ v and grid voltage V g Construct the output power response matrix of the grid converter; The feedback factor calculation module, signal-connected to the power response matrix construction module, is used to receive the output power response matrix and calculate the power angle motion state feedback factor of the amplitude and phase motion equations. G δ ; The stability assessment module is signal-connected to the feedback factor calculation module and is used to receive the power angle motion state feedback factor. G δ To determine system stability; The virtual impedance introduction and matrix correction module is connected to the stability judgment module and the power response matrix construction module, respectively, and is used to introduce virtual impedance when the system approaches the instability boundary. R v And correct the output power response matrix; The voltage reference value generation module, connected to the virtual impedance introduction and matrix correction module, receives the corrected output power response matrix and generates the output voltage reference value of the grid converter. v * oabc .

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