Transfer function parameter optimization method and system for voltage source converter grid-connected system

Abstract

The present invention discloses a method and system for optimizing the transfer function parameters of a voltage source converter grid-connected system, comprising: establishing a mathematical model based on a typical topology of the voltage source converter grid-connected system; processing the mathematical model to obtain an analytical transfer function capable of characterizing the stability of the voltage source converter grid-connected system; analyzing and obtaining an amplitude-frequency curve and a phase-frequency curve based on the analytical transfer function; calculating the shear frequency of the analytical transfer function of the voltage source converter grid-connected system based on the phase-frequency curve; substituting the shear frequency into the amplitude-frequency curve to obtain optimized control parameters of the converter that meet the requirements for safe and stable operation of the grid-connected system; and controlling the voltage source converter grid-connected system based on the optimized control parameters. The present invention can consider the impact of interactions between control links of the converter grid-connected system, between control links and main circuit parameters, and between control links and system operating status on the optimization of control parameters.

Description

Technical Field

[0001] The present invention relates to the technical field of voltage source converter grid-connected control, and in particular to a method and system for optimizing transfer function parameters of a voltage source converter grid-connected system. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] The penetration of voltage source converters (VSCs), exemplified by renewable energy and flexible direct current (FDC) technologies, in power systems is steadily increasing, and the trend toward power electronics is becoming increasingly pronounced. However, the large-scale integration of VSCs into power systems has triggered a series of broadband instabilities, posing significant challenges to the safe and stable operation of power systems.

[0004] Research indicates that this broadband instability phenomenon is driven by the voltage-source converter control system. Strong interactions exist between the converter control system and the high-impedance AC system to which it is connected, leading to reduced system damping and, consequently, system instability. Limited by the interrupting capacity of AC system circuit breakers, the conflict between the AC system's insufficient short-circuit capacity and the limited current-breaking capability of control and protection equipment is increasingly exacerbated. Therefore, optimizing the converter control structure and parameters is essential for enhancing grid-connected system stability.

[0005] Compared to converter control structure optimization methods, control parameter optimization methods are more economical, easier to implement, and do not require additional equipment in the grid-connected system. Existing converter grid-connected system parameter design methods generally fail to consider the interactions between the various control links in the grid-connected system, resulting in poor adaptability of control parameters.

[0006] The analytical transfer function method based on the state-space small-signal model is an effective method for analyzing the stability of grid-connected converter systems. Therefore, the stability margin of the grid-connected system can be quantitatively characterized by the amplitude margin of the transfer function. When the transfer function model, operating state, and main circuit parameters are constant, the optimal parameters that meet system stability can be obtained based on the amplitude margin. However, the shear margin of the analytical transfer function is easily affected by multiple factors such as AC system parameters and control system parameters, making it difficult to directly and accurately calculate the shear frequency of the transfer function. Existing work generally assumes that the phase-locked loop bandwidth is approximately equal to the shear frequency of the transfer function to simplify the parameter design process. However, in complex operating environments, such simplified methods can easily lead to grid-connected system parameters that fail to meet actual stability requirements. Summary of the Invention

[0007] To address the above-mentioned issues, the present invention proposes a method and system for optimizing the transfer function parameters of a voltage source converter grid-connected system. Based on the phase-frequency curve of the analytical transfer function, the analytical expression of the transfer function phase-frequency curve is subjected to a first-order linear expansion at the phase-locked loop bandwidth frequency. The clipping frequency of the analytical transfer function is estimated based on the phase-locked loop bandwidth frequency, and then applied to enhance the grid-connected stability of the voltage source converter.

[0008] In some embodiments, the following technical solutions are adopted:

[0009] A method for optimizing transfer function parameters of a voltage source converter grid-connected system, comprising:

[0010] Establishing a mathematical model based on a typical topology of a voltage source converter grid-connected system; processing the mathematical model to obtain an analytical transfer function capable of characterizing the stability of the voltage source converter grid-connected system;

[0011] According to the analytical transfer function, respectively analyzing and obtaining an amplitude-frequency curve and a phase-frequency curve;

[0012] Based on the phase-frequency curve, calculating the shear frequency of the analytical transfer function of the voltage source converter grid-connected system;

[0013] The shear frequency is brought into the amplitude-frequency curve to obtain converter optimization control parameters that meet the requirements of safe and stable operation of the grid-connected system; and the voltage source converter grid-connected system is controlled based on the optimization control parameters.

[0014] As a further solution, a mathematical model is established based on the typical topology of the voltage source converter grid-connected system, specifically:

[0015]

[0016]

[0017] in, They represent the d-axis current reference value in the reference coordinate system and the d-axis current response in the main circuit coordinate system respectively; G closed , G0 represent the equivalent closed-loop transfer function and open-loop transfer function of the grid-connected system respectively; s represents the Laplace operator; i sd0 、u sd0 Represent the steady-state values ​​of grid-connected current and voltage respectively; R g 、L g Represents the equivalent resistance and equivalent inductance of the AC system; ω pll 、ω CL represents the phase-locked loop bandwidth and the current loop bandwidth; ξ represents the damping ratio.

[0018] As a further solution, the mathematical model is processed to obtain an analytical transfer function that can characterize the stability of the voltage source converter grid-connected system, specifically:

[0019] The mathematical model is linearized to obtain a small-signal mathematical model of the voltage source converter grid-connected system; the small-signal mathematical model is simplified to obtain an analytical transfer function that can characterize the stability of the voltage source converter grid-connected system.

[0020] As a further solution, according to the analytical transfer function, the amplitude-frequency curve is obtained as follows:

[0021]

[0022] Where jω represents the input frequency of the transfer function; lg represents the logarithm calculation with base 10; arctan represents the inverse tangent calculation; |G0|, Represents the amplitude and phase angle of the transfer function; s represents the Laplace operator, i sd0 、u sd0 Represent the steady-state values ​​of grid-connected current and voltage respectively; R g , L g Represents the equivalent resistance and equivalent inductance of the AC system; ω pll 、ω CL represents the phase-locked loop bandwidth and the current loop bandwidth; ξ represents the damping ratio.

[0023] As a further solution, according to the analytical transfer function, the phase-frequency curve is obtained as follows:

[0024]

[0025] As a further solution, based on the phase-frequency curve, the shear frequency of the analytical transfer function of the voltage source converter grid-connected system is calculated, specifically:

[0026] According to the phase-frequency curve of the transfer function, it is pll Do a first-order linear expansion at the frequency, and get the phase-frequency curve at s=jω pll Slope at frequency

[0027] Calculate the transfer function phase-frequency curve at s=jω pll Phase angle at The difference from 180°;

[0028] Based on the slope The difference between the phase loop bandwidth and the actual cutoff frequency of the open-loop transfer function is obtained by e ;

[0029] Based on the difference Δωe Derive the open-loop transfer function clipping frequency.

[0030] As a further solution, the cut frequency of the open-loop transfer function is specifically:

[0031] ω k =ω pll +Δω e

[0032] Among them, ω pll Represents the phase-locked loop bandwidth.

[0033] In other embodiments, the following technical solutions are adopted:

[0034] A transfer function parameter optimization system for a voltage source converter grid-connected system, comprising:

[0035] A model processing module is used to establish a mathematical model based on a typical topology of a voltage source converter grid-connected system; and process the mathematical model to obtain an analytical transfer function capable of characterizing the stability of the voltage source converter grid-connected system;

[0036] a shear frequency calculation module, configured to obtain an amplitude-frequency curve and a phase-frequency curve according to the analytical transfer function; and calculate the shear frequency of the analytical transfer function of the voltage source converter grid-connected system based on the phase-frequency curve;

[0037] A parameter optimization control module is used to bring the shear frequency into the amplitude-frequency curve to obtain converter optimization control parameters that meet the safe and stable operation of the grid-connected system; and control the voltage source converter grid-connected system based on the optimization control parameters.

[0038] In other embodiments, the following technical solutions are adopted:

[0039] A terminal device includes a processor and a memory, wherein the processor is used to implement various instructions; the memory is used to store multiple instructions, and the instructions are suitable for being loaded and executed by the processor to implement the above-mentioned voltage source converter grid-connected system transfer function parameter optimization method.

[0040] In other embodiments, the following technical solutions are adopted:

[0041] A computer-readable storage medium stores a plurality of instructions, wherein the instructions are suitable for being loaded and executed by a processor of a terminal device to implement the above-mentioned method for optimizing transfer function parameters of a voltage source converter grid-connected system.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] (1) The method of the present invention can consider the influence of the interaction between the control links of the grid-connected converter system, between the control links and the main circuit parameters, and between the control links and the system operating state on the optimization of control parameters. While comprehensively considering the multi-time scale coupling phenomenon between the control links of the grid-connected converter system, it can meet the requirements of multiple operating states and different AC system parameters for the stable operation of the grid-connected converter; at the same time, it can avoid the influence of complex and changeable operating states and the main circuit parameter design process, and more accurately and directly derive control parameters that meet the safe and stable operation of the grid-connected system and are more adaptable. It is of great significance to ensure the safe and stable operation of the converter connected to the weak power grid by optimizing the control parameters.

[0044] (2) The present invention is based on the phase-frequency curve of the analytical transfer function, performs a first-order linear expansion on the analytical expression of the transfer function phase-frequency curve at the phase-locked loop bandwidth frequency, and estimates the shear frequency of the analytical transfer function according to the phase-locked loop bandwidth frequency, which is then applied to enhance the grid-connected stability of the voltage source converter. It can reduce the impact of inaccurate shear frequency estimation on parameter optimization and avoid the problem of system stability performance being less than expected due to optimistic parameter design caused by excessive AC system resistance.

[0045] Other features and advantages of additional aspects of the present invention will be given in part in the following description and in part will become obvious from the following description or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 Schematic diagram of a typical inverter grid-connected system in an embodiment of the present invention;

[0047] Figure 2 Schematic diagram of a transfer function parameter optimization method for a voltage source converter grid-connected system in an embodiment of the present invention. DETAILED DESCRIPTION

[0048] It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those skilled in the art to which the present application belongs.

[0049] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0050] Example 1

[0051] In one or more embodiments, a method for optimizing the transfer function parameters of a voltage source converter grid-connected system is disclosed. For the voltage source converter grid-connected system, an analytical transfer function model related to the stability of the grid-connected system is extracted, and its shear frequency is estimated based on the transfer function model. Then, by estimating the shear frequency and the amplitude-frequency curve of the analytical transfer function, the control system parameters are designed more accurately and quickly.

[0052] Reference Figure 2 The method of this embodiment specifically includes the following processes:

[0053] (1) Establish mathematical models and basic assumptions based on the typical topology of voltage source converter grid-connected systems;

[0054] In this embodiment, reasonable assumptions are made based on typical voltage source grid-connected converter control:

[0055] like Figure 1 As shown in the figure, in order to consider the stability of the direct-drive fan through the flexible direct delivery system, reasonable assumptions are adopted to simplify the analysis process.

[0056] The voltage feedforward link has no delay, and its transfer function G is approximately f ≈1.

[0057] The control link delay can be ignored, and its transfer function G is approximately d ≈1.

[0058] The outer loop control responds slowly, ignoring the dynamic influence of the outer loop control, and assuming that Δu dc ≈0.

[0059] In a specific embodiment, based on the typical topology structure model of the inverter grid-connected system, the closed-loop analytical transfer function model and the open-loop transfer function model of the inverter grid-connected system can be easily obtained:

[0060]

[0061] Among them, the superscripts "gf" and "cf" represent the electrical signals in the main circuit coordinate system and the control coordinate system respectively; They represent the d-axis current reference value in the reference coordinate system and the d-axis current response in the main circuit coordinate system respectively; G closed , G0 represent the equivalent closed-loop transfer function and open-loop transfer function of the grid-connected system respectively. The expression of the open-loop transfer function G0 is:

[0062]

[0063] Where s represents the Laplace operator; i sd0 、u sd0 Represent the steady-state values ​​of grid-connected current and voltage respectively; R g 、L gRepresents the equivalent resistance and equivalent inductance of the AC system; ω pll 、ω CL represents the phase-locked loop bandwidth and the current loop bandwidth; ξ represents the damping ratio, which is taken as 0.707 here.

[0064] (2) Linearizing the mathematical model in step (1) to obtain a small signal mathematical model of the voltage source converter grid-connected system;

[0065] (3) Simplifying the small signal model in step (2) to obtain an analytical transfer function that can characterize the stability of the voltage source converter grid-connected system;

[0066] (4) According to the transfer function obtained in step (3), the amplitude-frequency curve and the phase-frequency curve are obtained respectively;

[0067] In this embodiment, according to the analytical expression of the open-loop transfer function of the grid-connected converter, it can be known that the grid-connected system is a minimum phase system at this time, so the control parameters of the grid-connected system can be designed according to its amplitude margin.

[0068] According to the open-loop transfer function expression, the analytical expression of its amplitude-frequency curve can be obtained:

[0069]

[0070] Analytical expression of phase-frequency curve:

[0071]

[0072] Where jω represents the input frequency of the transfer function; lg represents the logarithm calculation with base 10; arctan represents the inverse tangent calculation; |G0|, Represents the amplitude and phase angle of the transfer function; s represents the Laplace operator, i sd0 、u sd0 Represent the steady-state values ​​of grid-connected current and voltage respectively; R g 、L g Represents the equivalent resistance and equivalent inductance of the AC system; ω pll 、ω CL represents the phase-locked loop bandwidth and the current loop bandwidth; ξ represents the damping ratio.

[0073] (5) estimating the shear frequency of the analytical transfer function of the voltage source converter grid-connected system based on the phase-frequency curve obtained in step (4);

[0074] In this embodiment, the phase-frequency curve of the grid-connected converter system has an approximately quadratic relationship with the input frequency. That is, the amplitude-frequency curve first increases with increasing input frequency, then decreases with increasing input frequency, and the phase-frequency curve has a unique extreme value within the entire frequency range. Assuming that the amplitude of the amplitude-frequency curve in each monotonic interval has an approximately linear relationship with the input frequency, the difference Δω between the phase-locked loop bandwidth and the actual cutoff frequency of the open-loop transfer function can be approximated by combining the phase-frequency curve. e , calculate the approximate value of the shear frequency of the open-loop transfer function ω k The specific process is as follows:

[0075] Step I: Analyze the phase-frequency curve according to the transfer function and convert it into the phase-frequency curve at s=jω. pll Doing a first-order linear expansion at the frequency and ignoring the higher-order terms, we can get the phase-frequency curve at s=jω pll Slope at frequency

[0076] Step II: Calculate the phase-frequency curve of the transfer function at s = jω pll Phase angle at The difference from 180°;

[0077] Step III, according to the transfer function phase-frequency curve at s=jω pll The slope and Taylor expansion at the frequency, combined with the results of step II, give the approximate difference Δω between the phase loop bandwidth and the actual cutoff frequency of the open-loop transfer function. e :

[0078]

[0079] Step IV: The approximate value of the shear frequency of the open-loop transfer function ω can be obtained according to the following formula k .

[0080] ω k =ω pll +Δω e (6)

[0081] (6) According to the shear frequency obtained in step (5), it is substituted into the amplitude-frequency curve. Given the design margin and the operating parameters of the converter grid-connected system, the converter optimization control parameters that meet the safe and stable operation of the grid-connected system can be obtained.

[0082] Assume the stability margin is k, and the open-loop transfer function clipping frequency approximation ω k By substituting the amplitude-frequency curve of the open-loop transfer function and inputting a given operating state, we can obtain the mutual constraints between the various control links of the grid-connected converter system when the stability margin is k.

[0083]

[0084] In the above formula, according to the given grid-connected system stability margin k, when the voltage source converter grid-connected system operating state u sd0 、i sd0 and control parameter ω CL , estimated bandwidth ω k Given , the PLL bandwidth can be directly calculated according to steps (5) and (6).

[0085] If the amplitude of the transfer function G0 calculated based on the PLL bandwidth is less than the grid-connected system stability margin k, the PLL bandwidth is corrected to the calculated PLL bandwidth ω after parameter tuning. pll , then repeat steps (5) and (6) until the amplitude of the transfer function G0 is not less than the grid-connected system stability margin k, and the phase-locked loop bandwidth ω that meets the grid-connected system stability requirements is obtained. pll .

[0086] Since the interaction between control links and the influence of AC system resistance are comprehensively considered in the parameter optimization process, the shear frequency of the open-loop transfer function can be estimated more accurately, thereby obtaining more effective and more widely applicable control parameters.

[0087] Example 2

[0088] In one or more embodiments, a transfer function parameter optimization system for a voltage source converter grid-connected system is disclosed, comprising:

[0089] A model processing module is used to establish a mathematical model based on a typical topology of a voltage source converter grid-connected system; and process the mathematical model to obtain an analytical transfer function capable of characterizing the stability of the voltage source converter grid-connected system;

[0090] a shear frequency calculation module, configured to obtain an amplitude-frequency curve and a phase-frequency curve according to the analytical transfer function; and calculate the shear frequency of the analytical transfer function of the voltage source converter grid-connected system based on the phase-frequency curve;

[0091] A parameter optimization control module is used to bring the shear frequency into the amplitude-frequency curve to obtain converter optimization control parameters that meet the safe and stable operation of the grid-connected system; and control the voltage source converter grid-connected system based on the optimization control parameters.

[0092] It should be noted that the specific implementation of the above modules has been described in Example 1 and will not be described in detail here.

[0093] Example 3

[0094] In one or more embodiments, a terminal device is disclosed, including a server. The server includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, the method for optimizing transfer function parameters of a voltage source converter grid-connected system according to Example 1 is implemented. For the sake of brevity, this description is omitted here.

[0095] It should be understood that in this embodiment, the processor may be a central processing unit (CPU), or may be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), off-the-shelf field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc.

[0096] The memory may include a read-only memory and a random access memory, and provides instructions and data to the processor. A portion of the memory may also include a non-volatile random access memory. For example, the memory may also store information about the device type.

[0097] During implementation, each step of the above method may be completed by an integrated logic circuit of hardware in a processor or by instructions in the form of software.

[0098] Example 4

[0099] In one or more embodiments, a computer-readable storage medium is disclosed, in which a plurality of instructions are stored, wherein the instructions are suitable for being loaded and executed by a processor of a terminal device to optimize the transfer function parameters of the voltage source converter grid-connected system described in Example 1.

[0100] Although the above describes the specific embodiments of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without any creative work are still within the scope of protection of the present invention.

Claims

1. A method for optimizing transfer function parameters of a voltage source converter grid-connected system, characterized in that: include: Establish a mathematical model based on the typical topology of the voltage source converter grid-connected system; Processing the mathematical model to obtain an analytical transfer function capable of characterizing the stability of the voltage source converter grid-connected system; According to the analytical transfer function, respectively analyzing and obtaining an amplitude-frequency curve and a phase-frequency curve; Based on the phase-frequency curve, the shear frequency of the analytical transfer function of the voltage source converter grid-connected system is calculated, specifically: According to the phase-frequency curve of the transfer function, s = jω pll Do a first-order linear expansion at the frequency, and get the phase-frequency curve at s = j ω pll Slope at frequency φ' ( x ); Calculate the transfer function phase-frequency curve in s = jω pll Phase angle at φ ( ω pll ) and 180°; Based on the slope φ' ( x ) and the difference, the approximate difference between the phase loop bandwidth and the actual cutoff frequency of the open-loop transfer function is obtained ; Based on the difference The shear frequency of the open-loop transfer function is obtained; The open-loop transfer function shear frequency is specifically: in, ω pll represents the phase-locked loop bandwidth; Substituting the shear frequency into the amplitude-frequency curve, and given the design margin and the operating parameters of the inverter grid-connected system, obtaining the inverter optimization control parameters that meet the safe and stable operation of the grid-connected system; The voltage source converter grid-connected system is controlled based on the optimized control parameters.

2. A method for optimizing transfer function parameters of a voltage source converter grid-connected system according to claim 1, characterized in that: A mathematical model is established based on the typical topology of the voltage source converter grid-connected system, specifically: Among them, ∆ i cf sdref,∆ i gf sd represent the reference coordinate system d The axis current reference value and the d-axis current respond in the main circuit coordinate system; G closed 、 G 0 represents the equivalent closed-loop transfer function and open-loop transfer function of the grid-connected system; s stands for Laplace operator; i sd0 、 u sd0 Represent the steady-state values ​​of grid-connected point current and voltage respectively; R g 、 L g Represents the equivalent resistance and equivalent inductance of the AC system; ω pll 、 ω CL Represents the phase-locked loop bandwidth and current loop bandwidth; ξ Represents the damping ratio.

3. The method for optimizing transfer function parameters of a voltage source converter grid-connected system according to claim 1, wherein: The mathematical model is processed to obtain an analytical transfer function that can characterize the stability of the voltage source converter grid-connected system, specifically: The mathematical model is linearized to obtain a small-signal mathematical model of the voltage source converter grid-connected system; the small-signal mathematical model is simplified to obtain an analytical transfer function that can characterize the stability of the voltage source converter grid-connected system.

4. The method for optimizing transfer function parameters of a voltage source converter grid-connected system according to claim 1, wherein: According to the analytical transfer function, the amplitude-frequency curve is obtained as follows: in, jω represents the input frequency of the transfer function; lg represents the logarithm calculation with base 10; arctan represents the inverse tangent calculation; | G 0|、 φ G0 Represents the amplitude and phase angle of the transfer function; s represents the Laplace operator, i sd0 、 u sd0 Represent the steady-state values ​​of grid-connected point current and voltage respectively; R g 、 L g Represents the equivalent resistance and equivalent inductance of the AC system; ω pll 、 ω CL Represents the phase-locked loop bandwidth and current loop bandwidth; ξ Represents the damping ratio.

5. A method for optimizing transfer function parameters of a voltage source converter grid-connected system according to claim 4, characterized in that: According to the analytical transfer function, the phase-frequency curve is obtained as follows: 。 6. A transfer function parameter optimization system for a voltage source converter grid-connected system, characterized in that: include: A model processing module is used to establish a mathematical model based on a typical topology of a voltage source converter grid-connected system; Processing the mathematical model to obtain an analytical transfer function capable of characterizing the stability of the voltage source converter grid-connected system; A shear frequency calculation module, configured to obtain an amplitude-frequency curve and a phase-frequency curve according to the analytical transfer function; Based on the phase-frequency curve, the shear frequency of the analytical transfer function of the voltage source converter grid-connected system is calculated, specifically: According to the phase-frequency curve of the transfer function, s = jω pll Do a first-order linear expansion at the frequency, and get the phase-frequency curve at s = j ω pll Slope at frequency φ' ( x ); Calculate the transfer function phase-frequency curve in s = jω pll Phase angle at φ ( ω pll ) and 180°; Based on the slope φ' ( x ) and the difference, the approximate difference between the phase loop bandwidth and the actual cutoff frequency of the open-loop transfer function is obtained ; Based on the difference The shear frequency of the open-loop transfer function is obtained; The open-loop transfer function shear frequency is specifically: in, ω pll represents the phase-locked loop bandwidth; A parameter optimization control module is used to bring the shear frequency into the amplitude-frequency curve, and given a design margin and operating parameters of the converter grid-connected system, obtain converter optimization control parameters that meet the safe and stable operation of the grid-connected system; and control the voltage source converter grid-connected system based on the optimized control parameters.

7. A terminal device comprising a processor and a memory, wherein the processor is used to implement various instructions; the memory is used to store multiple instructions, characterized in that: The instructions are suitable for being loaded by a processor and executed by the method for optimizing transfer function parameters of a voltage source converter grid-connected system according to any one of claims 1 to 5.

8. A computer-readable storage medium storing a plurality of instructions, characterized in that: The instructions are suitable for being loaded by a processor of a terminal device and executing the method for optimizing transfer function parameters of a voltage source converter grid-connected system according to any one of claims 1 to 5.

Images