Method, system and equipment for improving frequency modulation capability of network-forming converter based on voltage double-loop control parameters, and medium

Abstract

The invention discloses a method, a system, equipment and a medium for improving the frequency modulation capability of a network-building type converter based on voltage double-loop control parameters, and belongs to the technical field of safe operation of a power system, and the method comprises the steps: collecting the output current, terminal voltage and active power instruction values of the converter, and calculating a reference phase; converting the output current and the terminal voltage of the converter into two-phase components according to the reference phase; drawing a Bode diagram of the frequency transfer function, and determining an optimal integral parameter according to the phase change of the frequency transfer function; calculating an internal potential d-axis component and an internal potential q-axis component of the converter, and generating a control signal acting on the converter through pulse width modulation; optimization is carried out by adjusting integral parameters, excessive decrease of terminal voltage during a frequency event is suppressed, and the problem that the active supporting capacity is limited due to excessive decrease of the terminal voltage is avoided; the optimal integral parameter can be determined, and cooperative reliable operation of the voltage regulation function and the frequency modulation function of the converter is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of power system safe operation technology, specifically to a method, system, equipment, and medium for improving the frequency regulation capability of a grid-type converter based on voltage dual-loop control parameters. Background Technology

[0002] Wind and solar power generation using grid-connected converters employs phase-locked synchronization. During periods of active power deficit, the internal potential frequency rapidly tracks the terminal voltage frequency, resulting in a nearly constant power angle difference and weak active power support. Virtual synchronization technology simulates the rotor oscillation process of a synchronous machine. When an active power deficit occurs, the terminal voltage frequency drops rapidly while the internal potential frequency remains constant. This power angle difference increases the converter's output active power, thus suppressing further changes in system frequency.

[0003] Existing research on the inertia and primary frequency regulation response of grid-type converters mainly focuses on the virtual synchronization link, as this link simulates the synchronous machine rotor and is the main component providing virtual inertia and damping. It is worth noting that the process of increasing output power when the power angle swings up, as described above, primarily focuses on the dynamics of the internal potential frequency. However, the internal potential frequency is not equivalent to the frequency output by the virtual synchronization link; rather, it is the result of the combined effect of the virtual synchronization link frequency and the dynamics of the internal potential dq component.

[0004] Therefore, the control characteristics of the voltage inner loop also affect the frequency regulation performance of the converter. Without considering the impact of the voltage inner loop, excessive voltage drop during frequency events may limit active power support, or even cause voltage regulation problems due to voltage amplitude reaching the limit. Research on this issue has not yet received sufficient attention. Summary of the Invention

[0005] In view of the above-mentioned problems, the present invention is proposed.

[0006] Therefore, the technical problem solved by this invention is that existing research on frequency modulation response capability has not paid attention to the impact of the control characteristics of the voltage inner loop on the frequency modulation performance of the converter. This may result in limited active power support capability due to excessive voltage drop during frequency events, or even voltage regulation problems due to the voltage amplitude reaching the limit.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for improving the frequency modulation capability of a grid-type converter based on voltage dual-loop control parameters, comprising the following steps,

[0008] The converter's output current, terminal voltage, and active power command values ​​are collected, and the instantaneous active power of the converter is calculated based on the output current and terminal voltage.

[0009] The reference phase is calculated using the active power command value and the instantaneous active power;

[0010] Based on the reference phase, the converter's output current and terminal voltage are converted into two-phase components of the output current and two-phase components of the terminal voltage;

[0011] Construct frequency transfer functions for the changes in internal potential frequency and power, plot the Bode plot of the frequency transfer functions, adjust the initial integration parameters of the frequency transfer functions, record the phase changes of the frequency transfer functions in the Bode plot, and determine the optimal integration parameters based on the phase changes of the frequency transfer functions.

[0012] The d-axis component and q-axis component of the converter's internal potential are calculated using the optimal integration parameters, the two-phase component of the output current, and the two-phase component of the terminal voltage.

[0013] The d-axis and q-axis components of the internal potential are used to generate control signals that act on the converter through pulse width modulation.

[0014] As a preferred embodiment of the method for improving the frequency modulation capability of a grid-type converter based on voltage dual-loop control parameters according to the present invention, the step of calculating the reference phase using the active power command value and the instantaneous active power includes:

[0015] The instantaneous power difference is calculated by using the active power command value and the instantaneous active power;

[0016] A virtual synchronization transfer function is defined, and the angular frequency deviation is obtained by calculating the instantaneous power difference using the virtual synchronization transfer function.

[0017] Obtain the rated angular frequency of the power grid system, and calculate the reference frequency based on the rated angular frequency and the angular frequency deviation.

[0018] The reference phase is calculated using the reference frequency.

[0019] As a preferred embodiment of the method for improving the frequency modulation capability of a grid-type converter based on voltage dual-loop control parameters according to the present invention, the step of converting the output current and terminal voltage of the converter into two-phase components of the output current and two-phase components of the terminal voltage according to the reference phase includes:

[0020] The output current is converted into the α component and β component of the output current, and the terminal voltage is converted into the α component and β component of the terminal voltage.

[0021] Based on the reference phase, the α component and β component of the output current are converted into the d-axis component and q-axis component of the output current, which are then used as two-phase components of the output current.

[0022] Based on the reference phase, the terminal voltage α component and terminal voltage β component are converted into terminal voltage d-axis component and terminal voltage q-axis component, which are then used as two-phase components of the terminal voltage.

[0023] As a preferred embodiment of the method for improving the frequency modulation capability of a grid-type converter based on voltage dual-loop control parameters according to the present invention, the step of determining the optimal integral parameters based on the phase change of the frequency transfer function includes:

[0024] Draw a Bode plot of the frequency transfer function based on the frequency transfer function;

[0025] Adjust the initial integration parameters within the adjustment interval, and record the phase of the frequency transfer function after each adjustment of the initial integration parameters;

[0026] If the phase of the frequency transfer function reaches a maximum during the adjustment of the initial integration parameters, then the initial integration parameters corresponding to the maximum phase of the frequency transfer function are the optimal integration parameters.

[0027] If the phase of the frequency transfer function does not have a maximum value during the adjustment of the initial integration parameters, the adjustment of the initial integration parameters should be stopped when the difference between the phases of the frequency transfer function corresponding to two adjacent initial integration parameters is less than a set threshold, and the average value of the two initial integration parameters should be taken as the optimal integration parameters.

[0028] The advantages of this preferred technical solution are: it can determine the optimal integral parameters, optimize the dynamic characteristics of the internal potential, prevent the terminal voltage amplitude from hitting the limit, avoid voltage regulation abnormalities caused by the limit, and ensure the reliable coordinated operation of the converter's voltage regulation function and frequency modulation function.

[0029] As a preferred embodiment of the method for improving the frequency modulation capability of a grid-type converter based on voltage dual-loop control parameters according to the present invention, the step of calculating the d-axis component and q-axis component of the converter's internal potential using the optimal integral parameters, the two-phase component of the output current, and the two-phase component of the terminal voltage includes:

[0030] Set the command values ​​for the d-axis component and q-axis component of the terminal voltage;

[0031] The output current d-axis component command value and output current q-axis component command value are calculated using the two-phase component of the terminal voltage, the d-axis component command value of the terminal voltage, the q-axis component command value of the terminal voltage, and the optimal integration parameters.

[0032] The internal potential d-axis component and internal potential q-axis component are calculated by combining the output current d-axis component command value and the output current q-axis component command value with the two-phase components of the output current.

[0033] The d-axis and q-axis components of the internal potential are calculated based on the d-axis component, the q-axis component, and the reference frequency.

[0034] As a preferred embodiment of the method for improving the frequency modulation capability of a grid-type converter based on voltage dual-loop control parameters according to the present invention, the virtual synchronization transfer function is:

[0035]

[0036] in, This is a virtual synchronization transfer function. For virtual inertia, For virtual damping, For the Laplace operator;

[0037] The reference frequency is calculated based on the rated angular frequency and the angular frequency deviation; the formula for calculating the reference phase from the reference frequency is:

[0038]

[0039] in, This is the active power command value. Instantaneous active power The rated angular frequency, For reference frequency, This is the reference value for angular frequency. This is the reference phase.

[0040] As a preferred embodiment of the method for improving the frequency modulation capability of a grid-type converter based on voltage dual-loop control parameters according to the present invention, the frequency transfer function formula is:

[0041]

[0042] in, For frequency transfer function, For virtual inertia, For virtual damping, For the Laplace operator, Let be the steady-state value of the d-axis component of the internal electric potential. This represents the steady-state value of the internal electric potential. The system power angle coefficient, The equivalent reactance of the terminal filter of the grid-type converter. The proportional parameter for the d-axis component of the terminal voltage. Let be the initial integration parameters for the d-axis component of the terminal voltage. This represents the actual value of the d-axis component of the terminal voltage. This represents the steady-state value of the d-axis component of the current. This refers to power deviation.

[0043] The beneficial effects of this preferred technical solution are as follows: by constructing the transfer function between internal potential frequency and power change and optimizing it by adjusting the integral parameters, the excessive drop in terminal voltage during frequency events can be effectively suppressed, thus avoiding the problem of limited active power support capability caused by excessive drop in terminal voltage.

[0044] This invention provides a system for improving the frequency modulation capability of a grid-type converter based on voltage dual-loop control parameters.

[0045] To solve the above-mentioned technical problems, the present invention further provides the following technical solution: a network converter frequency modulation capability enhancement system based on voltage dual-loop control parameters, comprising: a data acquisition module for acquiring the converter's output current, terminal voltage, and active power command value;

[0046] The first data processing module calculates the instantaneous output active power of the grid-type converter; it calculates the d-axis component and q-axis component of the converter's internal potential using the optimal integration parameters, the two-phase components of the output current, and the two-phase components of the terminal voltage.

[0047] Second data processing module: Adjust the initial integration parameters of the frequency transfer function, record the phase change of the frequency transfer function in the Bode plot, and determine the optimal integration parameters based on the phase change of the frequency transfer function.

[0048] Coordinate transformation module: Converts the output current and terminal voltage of the converter into two-phase components of the output current and two-phase components of the terminal voltage;

[0049] Control generation module: The d-axis component and q-axis component of the internal potential are used to generate control signals that act on the converter through pulse width modulation.

[0050] The present invention provides a computer device, including a memory and a processor, wherein the memory stores a computer program, characterized in that the processor, when executing the computer program, implements the steps of a method for improving the frequency modulation capability of a grid-type converter based on voltage dual-loop control parameters.

[0051] The present invention provides a computer-readable storage medium having a computer program stored thereon, characterized in that the computer program, when executed by a processor, implements the steps of a method for improving the frequency modulation capability of a grid-type converter based on voltage dual-loop control parameters.

[0052] The beneficial effects of this invention are as follows: This invention breaks through the limitations of traditional methods that only focus on the virtual synchronization link. Outside of the virtual synchronization link, by constructing a frequency transfer function between the internal potential frequency and power change and optimizing it by adjusting the integral parameters, it effectively suppresses excessive voltage drop during frequency events, avoiding the problem of limited active power support capacity due to excessive voltage drop. It can determine the optimal integral parameters, optimize the dynamic characteristics of the internal potential, prevent the voltage amplitude from hitting the limit, avoid voltage regulation anomalies caused by the limit, and ensure the coordinated and reliable operation of the converter's voltage regulation and frequency modulation functions. Based on parameter adjustment and Bode plot phase analysis, this invention does not require significant changes to the original control strategy of the grid-type converter, achieving low cost, strong compatibility, and easy promotion and application. Attached Figure Description

[0053] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0054] Figure 1 A flowchart illustrating the overall process of a method for improving the frequency modulation capability of a grid-type converter based on voltage dual-loop control parameters, as provided in one embodiment of the present invention.

[0055] Figure 2 A typical power electronic converter grid connection diagram provided for embodiments of this application;

[0056] Figure 3 A control block diagram of a grid-type converter based on voltage dual-loop asymmetric control provided in an embodiment of this application;

[0057] Figure 4 A schematic diagram of the structure of the frequency modulation capability enhancement device for a grid-type converter provided in this application embodiment;

[0058] Figure 5 A comparative Bode plot of the frequency transfer function under different integration parameters provided in an embodiment of the present invention;

[0059] Figure 6 The active power response waveform of the grid-type converter based on voltage dual-loop asymmetric control during the response to the deficit active power disturbance is provided in the embodiments of this application.

[0060] Figure 7 The waveform diagram of the system frequency response of the grid-type converter based on voltage dual-loop asymmetric control in response to the active power deficit disturbance provided in the embodiments of this application is shown. Detailed Implementation

[0061] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0062] Example 1, referring to Figure 1 This is the first embodiment of the present invention, which provides a method for improving the frequency modulation capability of a grid-type converter based on voltage dual-loop control parameters, including:

[0063] S100: Collects the output current, terminal voltage and active power command value of the converter, and calculates the instantaneous active power of the converter based on the output current and terminal voltage;

[0064] S200: Calculate the reference phase using the active power command value and instantaneous active power;

[0065] S300: Based on the reference phase, convert the converter's output current and terminal voltage into two-phase components of the output current and two-phase components of the terminal voltage;

[0066] S400: Construct the frequency transfer function of the internal potential frequency change and the power change, and draw the Bode plot of the frequency transfer function. Adjust the initial integration parameters of the frequency transfer function, record the phase change of the frequency transfer function in the Bode plot, and determine the optimal integration parameters based on the phase change of the frequency transfer function.

[0067] S500: Calculates the d-axis component and q-axis component of the converter's internal potential using the optimal integration parameters, the two-phase component of the output current, and the two-phase component of the terminal voltage.

[0068] S600: The d-axis component and q-axis component of the internal potential are used to generate a control signal that acts on the converter through pulse width modulation.

[0069] It should be noted that in a real second-order system, increasing the virtual inertia is beneficial for optimizing the device's fast inertia response characteristics, but it has limited help for the subsequent second-level frequency regulation characteristics. It is difficult to continuously provide power support to improve the minimum or maximum frequency, and a large inertia has an adverse effect on system stability. Increasing the virtual damping helps improve the frequency regulation characteristics, but it affects the steady-state power output and increases the steady-state frequency regulation burden of power electronic equipment. Therefore, it is very important to improve the converter's dynamic frequency regulation capability while keeping the virtual inertia and damping parameters at preset values.

[0070] It should be noted that in the technical field of grid-connected converters participating in grid frequency regulation, the effectiveness of active power support and the stability of terminal voltage under frequency events are the core prerequisites for ensuring the safe operation of the grid. Current research on the frequency regulation response capability of converters generally focuses on optimizing the virtual synchronization link, neglecting the impact of voltage inner loop control characteristics on frequency regulation performance. When a frequency event is triggered by an active power deficit in the grid, the unoptimized voltage inner loop control will directly lead to a significant drop in terminal voltage, exacerbating the risk of grid frequency instability and seriously threatening the grid operation safety in scenarios with a high proportion of new energy connected to the grid. Therefore, it is very important to study the impact of voltage inner loop control characteristics on the frequency regulation performance of converters in order to improve the frequency regulation capability of converters.

[0071] Therefore, to address the aforementioned power system stability issues, steps S100-S600 are used to construct the transfer function between internal potential frequency and power change and optimize it by adjusting integral parameters. This effectively suppresses excessive voltage drop during frequency events, avoiding the problem of limited active power support capacity due to excessive voltage drop. The optimal integral parameters can be determined, optimizing the dynamic characteristics of the internal potential d-axis and q-axis components, preventing the voltage amplitude from hitting the limit, avoiding voltage regulation anomalies caused by the limit, and ensuring the reliable coordinated operation of the converter's voltage regulation and frequency regulation functions.

[0072] Example 2, refer to Figures 1-3 This is the second embodiment of the present invention, which provides a method for improving the frequency modulation capability of a grid-type converter based on voltage dual-loop control parameters.

[0073] In this embodiment of the application, step S100 involves collecting the output current, terminal voltage, and active power command value of the converter. The converter is a grid-type converter, which is a device that converts DC capacitor energy into AC electrical energy. Its components include DC capacitors, switching transistors, controllers, and output port filters. The virtual synchronization link of the grid-type converter simulates the rotor synchronization process of a synchronous machine. Active power is used as the input of the synchronization link. The active power is calculated from the three-phase AC voltage and current. Therefore, when collecting data from the grid-type converter, data such as output current and terminal voltage can be collected at the grid connection point using tools such as data acquisition cards, multimeters, or voltage and current sensors. Here, the grid connection point refers to the interface point where the grid-type converter outputs electrical energy to the power grid, which is usually located after the terminal filter.

[0074] The output current of the acquisition converter is a three-phase current. , and The terminal voltage is a three-phase voltage. , and ;

[0075] In this embodiment of the application, the formula for calculating the instantaneous active power of the converter based on the output current and terminal voltage in step S100 is as follows:

[0076]

[0077] in, Instantaneous active power , and These are the voltages at the three-phase terminals a, b, and c, respectively. , and These are the output currents for phases a, b, and c, respectively.

[0078] In this embodiment, the three-phase terminal voltages of a, b, and c are 220V, 219V, and 221V, respectively, and the three-phase output currents of a, b, and c are 4.8A, 5.1A, and 5A, respectively. These values ​​are calculated using the instantaneous active power calculation formula. 222×4.8+219×5.1+221×5.0=3287.5W.

[0079] In an optional implementation, the instantaneous active power of the converter calculated in step S100 can also be obtained by transforming the output current and terminal voltage in the three-phase stationary coordinate system to the output current and terminal voltage in the two-phase rotating coordinate system through coordinate transformation, and then multiplying and summing the output current and terminal voltage in the two-phase rotating coordinate system respectively to obtain the instantaneous active power.

[0080] In another optional implementation, the instantaneous active power of the converter calculated in step S100 can also be obtained by decomposing the output current and terminal voltage into harmonic components of different frequencies through Fourier transform. The instantaneous active power is generated by the interaction of voltage and current harmonic components of the same frequency. The three-phase output current and terminal voltage are decomposed into harmonic components of each order through Fourier transform, and the instantaneous active power is obtained by multiplying and summing the voltage and current components of each harmonic.

[0081] In this embodiment of the application, the calculation of the reference phase in step S200 using the active power command value and the instantaneous active power includes the following steps A1-A4:

[0082] A1: Calculate the instantaneous power difference using the active power command value and the instantaneous active power;

[0083] In this embodiment of the application, the formula for calculating the instantaneous power difference is:

[0084]

[0085] in, This is the instantaneous power difference. This is the active power command value. Instantaneous active power;

[0086] Specifically, the active power command value is set to 120kW, the instantaneous active power is 90kW, and the instantaneous power difference is calculated to be 30kW by substituting into the instantaneous power difference formula.

[0087] A2: Set a virtual synchronization transfer function, and calculate the angular frequency deviation by using the instantaneous power difference and the virtual synchronization transfer function;

[0088] In this embodiment, the virtual synchronization transfer function formula is:

[0089]

[0090] in, This is a virtual synchronization transfer function. For virtual inertia, For virtual damping, For the Laplace operator;

[0091] The formula for calculating the angular frequency deviation using the instantaneous power difference and the virtual synchronization transfer function is as follows:

[0092] ;

[0093] in, For angular frequency deviation, This is a virtual synchronization transfer function. This is the active power command value. Instantaneous active power;

[0094] Specifically, the damping ratio is set to 0.7, the active power command is 120kW, the instantaneous active power is 90kW, and the virtual inertia is... The virtual damping is 4. Given a value of 100, we choose a transient initial stage s=0.1.

[0095] Substituting into the transfer function formula, we can calculate... The formula for calculating angular frequency deviation is used to obtain the result. .

[0096] A3: Obtain the rated angular frequency of the power grid system, and calculate the reference frequency based on the rated angular frequency and the angular frequency deviation;

[0097] In this embodiment of the application, the formula for calculating the reference frequency based on the rated angular frequency and the angular frequency deviation is as follows:

[0098] ;

[0099] in, This is a virtual synchronization transfer function. This is the active power command value. Instantaneous active power; For the rated frequency, For reference frequency;

[0100] Specifically, the active power command value is set to 120kW, the instantaneous active power is 90kW, the virtual synchronous transfer function is -0.0092, and the rated frequency is 314rad / s. Substituting these values ​​into the reference frequency formula, the following calculations are obtained: .

[0101] A4: The reference phase is calculated using the reference frequency.

[0102] In this embodiment of the application, the formula for calculating the reference phase using the reference frequency is as follows:

[0103] ;

[0104] in, As a reference phase, For reference frequency, This is the frequency reference value;

[0105] Specifically, the frequency reference value is set at 314 rad / s. The value is 313.724 rad / s, and the Laplace operator is 0.1.

[0106] Substituting into the formula, the reference phase is calculated. =313.724×314 / 0.1=985093.36, and the remainder of the calculation result divided by 2π is 1.345 rad, which is approximately 77.1°.

[0107] In this embodiment of the application, step S300, which converts the output current and terminal voltage of the converter into two-phase components of the output current and two-phase components of the terminal voltage according to the reference phase, includes the following steps B1-B3:

[0108] B1: Convert the output current into the α component and β component of the output current, and convert the terminal voltage into the α component and β component of the terminal voltage;

[0109] In this embodiment, the output current is converted into the α component and β component of the output current through the Clarke transformation. The Clarke transformation formula for the output current is:

[0110] ;

[0111] in, The output current α component, The output current β component is set; the three-phase output current is set. , and The currents are 5A, 3A, and 4A respectively. Substituting these values ​​into the Clarke transform formula for the output current, we obtain the following results:

[0112] ;

[0113] ;

[0114] The terminal voltage is converted into its α and β components using the Clarke transform. The Clarke transform formula for the terminal voltage is:

[0115] ;

[0116] in, For the terminal voltage α component, The terminal voltage β component is used; the three-phase terminal voltage is set. , and The voltages are 230V, 210V, and 220V respectively; substituting these values ​​into the Clarke transform formula, we can calculate:

[0117] ;

[0118] .

[0119] In one alternative implementation, the output current can be converted into α and β components through symmetrical component transformation. The three-phase output current is first decomposed into positive-sequence, negative-sequence, and zero-sequence components using the symmetrical component transformation formula. The zero-sequence component can be ignored due to the low imbalance of the three-phase current. Then, the mapping relationship between the positive and negative-sequence components and the αβ coordinate system is used. The positive-sequence component corresponds to a rotating vector that is in phase with the α axis and orthogonal to the β axis, and the negative-sequence component corresponds to a rotating vector that is in the opposite direction. The α and β components of the output current are obtained by vector synthesis.

[0120] In another alternative implementation, the output current can be converted into its α and β components using a Fourier transform combined with a coordinate mapping method. For a three-phase output current containing harmonics, the fundamental component is extracted using a Fourier transform to obtain the amplitude I of the fundamental current. m And the initial phase θ, and then consider the fundamental current as a stationary vector in the αβ coordinate system, where the α component is β component is This enables the conversion from three-phase current to αβ components.

[0121] B2: Based on the reference phase, the α component and β component of the output current are converted into the d-axis component and q-axis component of the output current, which are then used as two-phase components of the output current.

[0122] In this embodiment, the α and β components of the output current are converted into d-axis and q-axis components using Parker transformation. The Parker transformation formula for the two-phase components of the output current is as follows:

[0123] ;

[0124] in, The output current is the d-axis component. This represents the q-axis component of the output current. The output current α component, For the output current β component, Assuming a reference phase; setting the output current α component to 1A, the output current β component to -0.577A, and the reference phase to 30°, the following calculation is obtained using the Parker transform formula for the two-phase current components:

[0125] ;

[0126] d-axis component of output current and the q-axis component of the output current As the two-phase components of the output current.

[0127] B3: Based on the reference phase, the terminal voltage α component and terminal voltage β component are converted into terminal voltage d-axis component and terminal voltage q-axis component, which are then used as two-phase components of the terminal voltage.

[0128] In this embodiment, the terminal voltage α component and terminal voltage β component are converted into terminal voltage d-axis component and terminal voltage q-axis component using Parker transformation. The Parker transformation formula for the two-phase components of the terminal voltage is as follows:

[0129]

[0130] in, The terminal voltage d-axis component, The terminal voltage q-axis component For the terminal voltage α component, For the terminal voltage β component, Use the reference phase; set the terminal voltage α component. 10V, terminal voltage β component Given a voltage of -5.77V and a reference phase of 30°, the Parker transform formula for the two-phase components of the terminal voltage is used to calculate the following:

[0131] ;

[0132] The d-axis component and q-axis component of the terminal voltage are considered as the two-phase components of the terminal voltage.

[0133] In this embodiment of the application, the step S400 of determining the optimal integration parameters based on the phase change of the frequency transfer function includes the following steps C1-C4:

[0134] C1: Draw the Bode plot of the frequency transfer function based on the frequency transfer function;

[0135] In this embodiment, the frequency transfer function formula is:

[0136]

[0137] in, For frequency transfer function, For virtual inertia, For virtual damping, For the Laplace operator, Let be the steady-state value of the d-axis component of the internal electric potential. This represents the steady-state value of the internal electric potential. The system power angle coefficient, The equivalent reactance of the terminal filter of the grid-type converter. The proportional parameter for the d-axis component of the terminal voltage. Let be the initial integration parameters for the d-axis component of the terminal voltage. This represents the actual value of the d-axis component of the terminal voltage. This represents the steady-state value of the d-axis component of the current. Power deviation;

[0138] Specifically, the virtual inertia is set to 4, the virtual damping to 100, the Laplace operator to 0.1, the steady-state value of the internal potential d-axis component to 1 per unit, the system power angle coefficient to 0.95, the equivalent reactance of the grid-type converter terminal filter to 0.1 per unit, the proportional parameter of the terminal voltage d-axis component to 0.5, the actual value of the terminal voltage d-axis component to 220V, the steady-state value of the current d-axis component to 3A, and the power deviation to 20kW.

[0139] The oscillating component frequency in the original frequency response waveform was determined by simulation as the frequency of interest, and Bode plot of the frequency transfer function at the frequency of interest was plotted using MATLAB.

[0140] C2: Adjust the initial integration parameters within the adjustment interval, and record the phase of the frequency transfer function after each adjustment of the initial integration parameters;

[0141] In this embodiment, the adjustment range is set to 0.1~15. The initial integration parameter is adjusted starting from 15 and is halved each time. The initial integration parameter values ​​are 15, 7.5, 3.75, 1.875, 0.9375, 0.4688, and 0.2344, respectively. The corresponding phases of the frequency transfer function are 141, 135.2, 130.5, 127.8, 126.5, 125.8, and 125.4, respectively.

[0142] C3: If the phase of the frequency transfer function does not have a maximum value during the adjustment of the initial integration parameters, stop adjusting the initial integration parameters when the difference between the phases of the frequency transfer function corresponding to two adjacent initial integration parameters is less than a set threshold, and take the average of the two initial integration parameters as the optimal integration parameters.

[0143] In this embodiment, the threshold is set to 2. The phase of the frequency transfer function decreases sequentially without a maximum value. By comparing the initial integration parameter adjusted from 1.875 to 0.9375, the corresponding phase of the frequency transfer function changes from 127.8 to 126.5, with a phase difference of 1.3, which is less than the set threshold and meets the stopping condition. The average of the two initial integration parameters 1.875 and 0.9375 is taken as 1.406, and 1.406 is the optimal integration parameter.

[0144] C4: If the phase of the frequency transfer function reaches a maximum during the adjustment of the initial integration parameters, then the initial integration parameters corresponding to the maximum phase of the frequency transfer function are the optimal integration parameters.

[0145] In this embodiment, the adjustment range is set to 0.1~15. The initial integration parameter is adjusted starting from 15 and is halved each time. The initial integration parameter values ​​are 15, 7.5, 3.75, 1.875, 0.9375, 0.4688, and 0.2344, respectively. The corresponding phases of the frequency transfer function are 25.3, 31.8, 38.2, 35.5, 30.1, 25.7, and 22.3, respectively. There is a maximum value in the phase of the frequency transfer function. The initial integration parameter corresponding to the maximum value of the phase of the frequency transfer function is 3.75. Therefore, 3.75 is the optimal integration parameter.

[0146] In this embodiment of the application, step S500, which calculates the d-axis component and q-axis component of the converter's internal potential using the optimal integration parameters, the two-phase component of the output current, and the two-phase component of the terminal voltage, includes the following steps D1-D4:

[0147] In an alternative implementation, the optimal integral parameters can also be determined using a particle swarm optimization algorithm. First, the integral parameters are used as variables to be optimized, and a fitness function that comprehensively considers the phase of the frequency transfer function and the frequency modulation performance of the system is constructed. Then, within the parameter search range of 0.1 to 15, a population of 30 particles is initialized, with each particle corresponding to an initial candidate value for the integral parameters. Next, based on the historical best value and the global best value of the particles, the integral parameters are iteratively updated using an update formula. The iteration stops when the change in the global best value is less than a set threshold for five consecutive generations, and finally, integral parameters that minimize the frequency deviation during system frequency modulation are obtained.

[0148] In another alternative implementation, the optimal integral parameters can be determined using a genetic algorithm. First, the integral parameters are used as variables to be optimized. These parameters are encoded in 16-bit binary, and an initial population of 40 individuals is randomly generated. A fitness function is defined, which comprehensively evaluates whether the phase of the frequency transfer function meets the requirements and the quality of the system's frequency modulation performance. Then, genetic operations are performed, using roulette wheel selection, single-point crossover, and bit-flipping mutation to continuously iterate and evolve the population. The iteration terminates when 50 generations have passed or the fitness no longer changes significantly. Finally, the individual with the highest fitness is decoded to obtain the optimal integral parameters.

[0149] D1: Sets the command values ​​for the d-axis component and q-axis component of the terminal voltage;

[0150] In this embodiment, under the synchronous rotating dq coordinate system, the setting of the terminal voltage dq axis command value needs to meet two core objectives: the terminal voltage d-axis component command value controls the amplitude stability of the terminal voltage, which is usually related to the system rated voltage and reactive power demand; the terminal voltage q-axis component command value controls the active power balance of the terminal voltage, which needs to be adjusted in conjunction with the active power difference. If there is a power surplus, its negative amplitude can be appropriately reduced; if there is a power deficiency, its negative amplitude can be appropriately increased. The active power output is guided by the terminal voltage q-axis component command value to match the power demand.

[0151] Specifically, the commanded value for the d-axis component of the terminal voltage is 6V, and the commanded value for the q-axis component of the terminal voltage is -9.5V.

[0152] D2: Calculate the output current d-axis component command value and output current q-axis component command value using the two-phase components of the terminal voltage, the d-axis component command value of the terminal voltage, the q-axis component command value of the terminal voltage, and the optimal integration parameters;

[0153] In this embodiment of the application, the formulas for calculating the command values ​​of the d-axis component and the q-axis component of the output current are as follows:

[0154] ;

[0155] in, This is the command value for the d-axis component of the output current. This is the command value for the q-axis component of the output current. This is the command value for the d-axis component of the terminal voltage. This is the command value for the q-axis component of the terminal voltage. and For the proportional parameters of the terminal voltage controller, and These are the integral parameters of the terminal voltage controller;

[0156] Specifically, the d-axis component of the terminal voltage is set to 5.775V, the q-axis component to -10V, the command value for the d-axis component to be 6V, and the command value for the q-axis component to be -9.5V. and It is 0.5. It is 10. It is 3.75;

[0157] In this embodiment, under steady state, the integral term gradually stabilizes the output. It is assumed that when the system reaches steady state...

[0158] In steady-state analysis, the Laplace operator s takes the value 0, at which point the integral term... The impact can be reflected through long-term integrals. Here, we first calculate the proportional part. At this point, the actual steady-state perspective of the project can be considered as... , Substituting the command values ​​of the d-axis component and q-axis component of the output current into the formula, we can calculate the result. , If the integral effect is considered, the integral term will gradually accumulate over time, making the current command more accurately track the voltage deviation and eventually eliminating the steady-state error.

[0159] D3: Calculate the d-axis component and q-axis component of the internal potential by combining the command values ​​of the d-axis component and q-axis component of the output current with the two-phase components of the output current.

[0160] The formulas for calculating the d-axis component and q-axis component of the internal electric potential are as follows:

[0161]

[0162] in, The d-axis component of the internal electric potential The internal potential is represented by the q-axis component. The terminal voltage d-axis component, The terminal voltage q-axis component The equivalent reactance of the converter terminal filter;

[0163] In this embodiment, the output current d-axis component command value is set to 1.8A, the output current q-axis component command value is set to 10.25A, the terminal voltage d-axis component is set to 5.775V, the terminal voltage q-axis component is set to -10V, and the converter terminal filter equivalent reactance is 0.1Ω. The internal potential d-axis component is calculated by substituting these values ​​into the formulas for the internal potential d-axis and q-axis components. 5.775 - 10.25 × 0.1 = 4.75 V, q-axis component of internal potential -10 + 0.8 × 0.1 = -9.82 V.

[0164] In this embodiment of the application, step S600, which generates a control signal for the converter by pulse width modulation of the d-axis component and the q-axis component of the internal potential, specifically includes:

[0165] After obtaining the d-axis and q-axis components of the internal potential, the control signal for the converter is generated through pulse width modulation (PWM). First, the real-time d-axis and q-axis components of the internal potential are compared with the voltage vector at the converter output terminal, and the deviation vector between the two is calculated. This deviation vector reflects the difference between the current internal potential and the actual output voltage, serving as the core input for PWM modulation. Based on space vector pulse width modulation (SVPWM) technology, according to the amplitude and phase of the deviation vector, the combination of converter switches to be activated at the current moment is determined within a preset voltage space vector, such as the eight basic switching states of a three-phase two-level converter. Then, through the principle of vector synthesis, the control signal is calculated... Calculate the conduction time of each switch; when the deviation vector points to a certain sector of the hexagon, select two adjacent non-zero voltage vectors and a zero vector of that sector, and allocate the conduction time proportionally to ensure that the synthesized output voltage vector approximates the target values ​​of the d-axis component and the q-axis component of the internal potential; convert the calculated conduction time of each switch into a corresponding PWM pulse signal (high and low level signal), which is applied to the power switching devices of the converter to control their conduction and turn-off, so that the AC voltage output by the converter tracks the changes of the d-axis component and the q-axis component of the internal potential in real time, thereby realizing the precise regulation of the system's active power, reactive power and terminal voltage, and ensuring the stable operation of the converter.

[0166] In an optional implementation, the d-axis component and q-axis component of the internal potential can be used to generate control signals through space vector modulation. The sectors where the d-axis component and q-axis component of the internal potential are located are calculated to determine the two adjacent non-zero basic voltage vectors and their durations. Combined with zero vector allocation, the conduction timing of each switch is calculated to generate 6 pulse signals to drive the converter, so that the output voltage vector approximates the d-axis component and q-axis component of the internal potential.

[0167] In another optional implementation, the d-axis component and q-axis component of the internal potential are used to generate a control signal through hysteresis comparison control. Reference currents corresponding to the d-axis component and q-axis component of the internal potential are set and the actual current is measured in real time. For the d-axis current, when the actual current exceeds the reference current, the upper bridge arm switch is triggered to turn off and the lower bridge arm is turned on to reduce the current. When the actual current is lower than the reference current, the opposite action is triggered. The same logic is used for the q-axis current, and a switching signal is generated through hysteresis comparison of the current deviation.

[0168] Example 3, referring to Figures 1-4 This is the third embodiment of the present invention, which provides a system for improving the frequency modulation capability of a grid-type converter based on voltage dual-loop control parameters, comprising:

[0169] Data acquisition module: Acquires the converter's output current, terminal voltage, and active power command values;

[0170] The first data processing module calculates the instantaneous output active power of the grid-type converter; it calculates the d-axis component and q-axis component of the converter's internal potential using the optimal integration parameters, the two-phase components of the output current, and the two-phase components of the terminal voltage.

[0171] Second data processing module: Adjust the initial integration parameters of the frequency transfer function, record the phase change of the frequency transfer function in the Bode plot, and determine the optimal integration parameters based on the phase change of the frequency transfer function.

[0172] Coordinate transformation module: Converts the output current and terminal voltage of the converter into two-phase components of the output current and two-phase components of the terminal voltage;

[0173] Control generation module: The d-axis component and q-axis component of the internal potential are used to generate control signals that act on the converter through pulse width modulation.

[0174] Example 4, the fourth embodiment of the present invention, differs from the previous three embodiments in that: if the function 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, the technical solution of the present invention, essentially, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of the present invention. The aforementioned storage medium includes: USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, optical disks, and other media capable of storing program code.

[0175] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-including system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device.

[0176] More specific examples (a non-exhaustive list) of computer-readable media include: electrical connections (electronic devices) having one or more wires, portable computer disk drives (magnetic devices), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Furthermore, computer-readable media can even be paper or other suitable media on which programs can be printed, because programs can be obtained electronically, for example, by optically scanning the paper or other media, followed by editing, interpreting, or otherwise processing as necessary, and then stored in computer memory.

[0177] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0178] Example 5, refer to Figures 5-7This is the fifth embodiment of the present invention, providing a method for improving the frequency regulation capability of a grid-connected converter based on voltage dual-loop control parameters. A grid-connected converter is a device that converts DC capacitor energy into AC electrical energy. Its components include DC capacitors, switching transistors, a controller, and an output port filter, and it achieves grid-connection functionality through corresponding grid-connected control. The virtual synchronization link of the grid-connected converter simulates the rotor synchronization process of a synchronous machine, using active power as the input quantity of the synchronization link. Active power is calculated from the three-phase AC voltage and current. Therefore, when acquiring data from the grid-connected converter, tools such as data acquisition cards, multimeters, or voltage and current sensors can be used to collect data such as output current and terminal voltage at the grid connection point. Here, the grid connection point refers to the interface point where the grid-connected converter outputs electrical energy to the power grid, typically located after the terminal filter.

[0179] Bode plots are a graphical method for representing frequency response. They consist of an amplitude-frequency response plot and a phase-frequency response plot, together depicting the characteristics of the system. Both are plotted on a logarithmic scale of frequency. The horizontal axis of the Bode plot represents frequency, and the vertical axis represents gain / phase. The horizontal axis is typically a logarithmic scale. The resulting Bode plot visually displays the frequency response characteristics of a target object, including the trends in gain, phase, and cutoff frequency at different frequencies.

[0180] Specifically, when plotting the equivalent inertia Bode plot for a mesh converter, the frequency range of the Bode plot can be determined first based on the characteristics and analysis requirements of the mesh converter. Then, the gain and phase at each frequency can be calculated based on the angular frequency of the mesh converter during operation. Subsequently, the gain curve and phase curve of the mesh converter can be plotted on logarithmic coordinates based on the gain and phase at each frequency. Typically, the plotting is performed from low frequency to high frequency.

[0181] The integral parameters of the d-axis voltage control of the grid-type converter are optimized to change the dynamic characteristics of the internal potential q-axis component and the internal potential frequency.

[0182] In this step, by changing the d-axis voltage control parameters, the internal potential q-axis component can be increased in the short term during the period when the terminal voltage d-axis component decreases, thereby suppressing frequency changes during this stage and improving the active power output of the grid converter during this stage.

[0183] First, draw the Bode plot of the frequency transfer function of the grid converter before optimization. The oscillation frequency is about 1.5Hz and the phase frequency characteristic is 142°.

[0184] Decreasing the integral parameter increases the optimized phase-frequency response by 15°, corresponding to an integral parameter of 1. Bode plot comparison, for example... Figure 5 As shown, the amplitude-frequency characteristics are similar before and after optimization at the frequency of interest, with only the phase-frequency characteristics changing.

[0185] The virtual inertia time constant parameter H of the grid-type converter is 4s, and the damping parameter D is 100. When the integral parameters are 3, 5, 10, 12, and 15, the active power response curve of the grid-type converter is as follows: Figure 6 As shown, the frequency response curve is as follows: Figure 7 As shown. According to Figure 6 and Figure 7 The results show that by using a larger d-axis voltage integral control parameter, the peak active power output of the grid-type converter at approximately 101s can be increased. However, since the voltage control is proportional-integral control, the d-axis voltage recovers rapidly after a brief decrease, leading to an increase in the system frequency variation, but this does not affect the frequency recovery process after the frequency minimum occurs. Although this method cannot simultaneously increase the frequency modulation power and raise the frequency minimum, it verifies the possibility of changing the frequency modulation capability of the grid-type converter by optimizing control elements other than the virtual synchronization link.

[0186] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for improving the frequency modulation capability of a grid-type converter based on voltage dual-loop control parameters, characterized in that, include: The converter's output current, terminal voltage, and active power command value are collected, and the instantaneous active power of the converter is calculated based on the output current and terminal voltage. The reference phase is calculated using the active power command value and the instantaneous active power; Based on the reference phase, the converter's output current and terminal voltage are converted into two-phase components of the output current and two-phase components of the terminal voltage; Construct frequency transfer functions for the changes in internal potential frequency and power, and plot the Bode plot of the frequency transfer functions. Adjust the initial integration parameters of the frequency transfer functions, record the phase changes of the frequency transfer functions in the Bode plot, and determine the optimal integration parameters based on the phase changes of the frequency transfer functions. The internal potential d-axis component and internal potential q-axis component of the converter are calculated using the optimal integration parameters, the two-phase components of the output current, and the two-phase components of the terminal voltage. The d-axis component and q-axis component of the internal potential are used to generate a control signal that acts on the converter through pulse width modulation.

2. The method for improving the frequency modulation capability of a grid-type converter based on voltage dual-loop control parameters as described in claim 1, characterized in that, The steps for calculating the reference phase using the active power command value and the instantaneous active power include: The instantaneous power difference is calculated by using the active power command value and the instantaneous active power; A virtual synchronization transfer function is set, and the angular frequency deviation is obtained by calculating the instantaneous power difference using the virtual synchronization transfer function. Obtain the rated angular frequency of the power grid system, and calculate the reference frequency based on the rated angular frequency and the angular frequency deviation; The reference phase is calculated using the reference frequency.

3. The method for improving the frequency modulation capability of a grid-type converter based on voltage dual-loop control parameters as described in claim 2, characterized in that, The steps of converting the converter's output current and terminal voltage into two-phase components of the output current and two-phase components of the terminal voltage based on the reference phase include: The output current is converted into an α component and a β component, and the terminal voltage is converted into an α component and a β component. Based on the reference phase, the α component and β component of the output current are converted into the d-axis component and q-axis component of the output current, which are then used as two-phase components of the output current. Based on the reference phase, the terminal voltage α component and terminal voltage β component are converted into terminal voltage d-axis component and terminal voltage q-axis component, which are then used as two-phase components of the terminal voltage.

4. The method for improving the frequency modulation capability of a grid-type converter based on voltage dual-loop control parameters as described in claim 3, characterized in that, The steps for determining the optimal integration parameters based on the phase change of the frequency transfer function include: Based on the frequency transfer function, draw the Bode plot of the frequency transfer function; Adjust the initial integration parameters within the adjustment interval, and record the phase of the frequency transfer function after each adjustment of the initial integration parameters; If the phase of the frequency transfer function reaches a maximum value during the adjustment of the initial integration parameters, then the initial integration parameters corresponding to the maximum value of the phase of the frequency transfer function are the optimal integration parameters. If the phase of the frequency transfer function does not have a maximum value during the adjustment of the initial integration parameters, the adjustment of the initial integration parameters shall be stopped when the difference between the phases of the frequency transfer function corresponding to two adjacent initial integration parameters is less than a set threshold, and the average value of the two initial integration parameters shall be taken as the optimal integration parameter.

5. The method for improving the frequency modulation capability of a grid-type converter based on voltage dual-loop control parameters as described in claim 4, characterized in that, The steps for calculating the d-axis and q-axis components of the converter's internal potential using the optimal integration parameters, the two-phase components of the output current, and the two-phase components of the terminal voltage include: Set the command values ​​for the d-axis component and q-axis component of the terminal voltage; The command values ​​of the output current d-axis component and the output current q-axis component are calculated using the two-phase components of the terminal voltage, the command values ​​of the terminal voltage d-axis component and the command values ​​of the terminal voltage q-axis component, and the optimal integration parameters. The internal potential d-axis component and internal potential q-axis component are calculated by combining the output current d-axis component command value and the output current q-axis component command value with the two-phase components of the output current. The d-axis component and q-axis component of the internal potential are calculated based on the d-axis component and q-axis component of the internal potential and the reference frequency.

6. A method for improving the frequency modulation capability of a grid-type converter based on voltage dual-loop control parameters as described in claim 2 or 5, characterized in that, The virtual synchronization transfer function is: ； in, This is a virtual synchronization transfer function. For virtual inertia, For virtual damping, For the Laplace operator; The reference frequency is calculated based on the rated angular frequency and the angular frequency deviation; the formula for calculating the reference phase from the reference frequency is: ； in, This is the active power command value. Instantaneous active power The rated angular frequency, For reference frequency, This is the reference value for angular frequency. This is the reference phase.

7. The method for improving the frequency modulation capability of a grid-type converter based on voltage dual-loop control parameters as described in claim 4, characterized in that, The formula for the frequency transfer function is: ； in, For frequency transfer function, For virtual inertia, For virtual damping, For the Laplace operator, Let be the steady-state value of the d-axis component of the internal electric potential. This represents the steady-state value of the internal electric potential. The system power angle coefficient, The equivalent reactance of the terminal filter of the grid-type converter. The proportional parameter for the d-axis component of the terminal voltage. Let be the initial integration parameters for the d-axis component of the terminal voltage. This represents the actual value of the d-axis component of the terminal voltage. This represents the steady-state value of the d-axis component of the current. This refers to power deviation.

8. A system for enhancing the frequency modulation capability of a grid-type converter based on voltage dual-loop control parameters, comprising applying the method for enhancing the frequency modulation capability of a grid-type converter based on voltage dual-loop control parameters as described in any one of claims 1 to 7, characterized in that, include: Data acquisition module: Acquires the converter's output current, terminal voltage, and active power command values; First data processing module: calculates the instantaneous output active power of the grid-type converter; The internal potential d-axis component and internal potential q-axis component of the converter are calculated using the optimal integration parameters, the two-phase components of the output current, and the two-phase components of the terminal voltage. Second data processing module: Adjusts the initial integration parameters of the frequency transfer function, records the phase change of the frequency transfer function in the Bode plot of the frequency transfer function, and determines the optimal integration parameters based on the phase change of the frequency transfer function; Coordinate transformation module: Converts the output current and terminal voltage of the converter into two-phase components of the output current and two-phase components of the terminal voltage; Control generation module: The d-axis component and q-axis component of the internal potential are used to generate a control signal that acts on the converter through pulse width modulation.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method for improving the frequency modulation capability of a grid-type converter based on voltage dual-loop control parameters as described in any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the method for improving the frequency modulation capability of a grid-type converter based on voltage dual-loop control parameters as described in any one of claims 1 to 7.

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