Frequency control method and terminal of follow-up network type converter series-parallel system

Abstract

The invention discloses a frequency control method and terminal for a network following and constructing type converter hybrid system. The method comprises the following steps: acquiring a first control parameter of a network following type converter during frequency response and a second control parameter of a network constructing type converter during frequency response; according to the first control parameter and the second control parameter, an objective function with the purpose of minimizing the frequency change rate of the follow-up network type converter hybrid system is constructed, and the optimal solutions of the first control parameter and the second control parameter are obtained by solving the objective function; and according to the optimal solution of the first control parameter and the second control parameter, frequency control is carried out on the following construction network type converter series-parallel system. In this way, the control parameters can be adjusted in a self-adaptive mode along with the working condition of the follow-up network type converter series-parallel system, the problem of frequency oscillation caused by complex interaction under the follow-up network type converter series-parallel system is solved, and stable and reliable operation of an electric power system is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of power system technology, and in particular to a frequency control method and terminal for a grid-connected converter hybrid system. Background Technology

[0002] As the penetration rate of new energy sources based on power electronic converters in the power system increases, traditional synchronous generators are gradually being replaced, resulting in a decrease in system inertia and damping, and a severe challenge to frequency stability.

[0003] Existing grid-connected converters rely on phase-locked loops for synchronization and lack independent frequency support capabilities. While grid-connected converters can simulate synchronous machine characteristics to provide inertia and voltage support, complex interactions in systems operating in conjunction with grid-connected converters can lead to new frequency oscillation problems, especially under weak grid conditions. Therefore, effectively improving the frequency stability of hybrid grid-connected and grid-connected converter systems is a critical technical issue that urgently needs to be addressed.

[0004] Existing frequency control methods mainly rely on grid-connected converters to provide frequency support, including the use of virtual synchronous machine control or droop control; while grid-connected converters often use additional virtual inertia or droop elements to provide a small amount of frequency support. However, the control parameters of current grid-connected and grid-connected converters are mostly designed based on fixed scenarios, lacking adaptability to grid strength and actual operating conditions.

[0005] Furthermore, existing frequency control methods typically employ a single parameter configuration. While this approach can provide stability under most normal operating conditions, it cannot be fully implemented when faced with complex and extreme power grid environments, leading to problems such as frequency fluctuations and system instability. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a frequency control method and terminal for a hybrid system of integrated grid converters, which can improve the stability of frequency control in the hybrid system of integrated grid converters under different power grid operating conditions.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A frequency control method for a grid-connected converter hybrid system includes the following steps: Obtain the first control parameters of the grid-connected converter at the frequency response, and the second control parameters of the grid-connected converter at the frequency response; Based on the first control parameter and the second control parameter, an objective function is constructed with the goal of minimizing the frequency change rate of the hybrid system of grid-type converters. Solve the objective function to obtain the optimal solutions for the first control parameters and the second control parameters; Frequency control is performed on the hybrid system of the grid converter based on the optimal solution of the first control parameter and the second control parameter.

[0008] To solve the above-mentioned technical problems, another technical solution adopted by the present invention is as follows: A frequency control terminal for a grid-connected converter hybrid system includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the various steps of the frequency control method for the grid-connected converter hybrid system described above.

[0009] The beneficial effects of this invention are as follows: First, it obtains the first control parameters of the grid-connected converter and the second control parameters of the grid-connected converter during frequency response. Based on the first and second control parameters, it constructs an objective function with the goal of minimizing the frequency change rate of the grid-connected converter hybrid system. By solving the objective function, it obtains the optimal solutions for the first and second control parameters. Frequency control of the grid-connected converter hybrid system is then performed based on these optimal solutions. In this way, the control parameters can be adaptively adjusted according to the operating conditions of the grid-connected converter hybrid system, solving the frequency oscillation problem caused by complex interactions in the grid-connected converter hybrid system and ensuring the stable and reliable operation of the power system. Attached Figure Description

[0010] Figure 1 This is a flowchart of a frequency control method for a hybrid system of grid-connected converters according to an embodiment of the present invention; Figure 2 This is a schematic diagram of a frequency control terminal for a grid-connected converter hybrid system according to an embodiment of the present invention. Figure 3 This is a schematic diagram of the mechanism for synchronizing the phase-angular frequency of the control voltage with the grid type according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the mechanism of active power-angular frequency synchronization controlled by a grid-type control according to an embodiment of the present invention; Figure 5 This is a flowchart of a frequency stability improvement method based on intelligent algorithms according to an embodiment of the present invention.

[0011] Label Explanation: 1. A frequency control terminal for a grid-connected converter hybrid system; 2. A memory; 3. A processor. Detailed Implementation

[0012] To explain in detail the technical content, objectives, and effects of the present invention, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0013] Before detailing the embodiments of this application, some related concepts will first be explained: 1. Grid-following converter: A type of power electronic device that relies on the voltage and frequency signals of the external power grid to operate. It does not have the ability to independently adjust the voltage and frequency, but passively follows the parameter changes of the main power grid. This type of device usually adjusts its output according to the real-time status of the power grid in order to maintain synchronous operation with the power grid. 2. Grid-type converter: A converter that can autonomously establish and maintain the amplitude, frequency, and phase of the AC output voltage; 3. Frequency response: The dynamic response behavior of the converter to changes in the grid frequency; 4. Phase-locked loop (PLL): The core synchronization unit of the grid converter, used to track the phase angle and frequency of the grid voltage in real time; 5. Phase-locked loop ratio: determines the instantaneous response speed of the phase-locked loop to phase errors; 6. Phase-locked loop integral coefficients: used to eliminate steady-state errors in phase tracking within the phase-locked loop; 7. Quadrature-axis voltage: The q-axis voltage in converter control based on a rotating coordinate system (dq axis); 8. Inertia: In traditional synchronous generators, inertia comes from the mechanical kinetic energy of the rotating rotor. When the power grid is unbalanced, the rotor releases or absorbs kinetic energy by accelerating / decelerating, thus buffering frequency changes. Grid-type converters simulate this process through algorithms, which is called inertia. 9. Damping coefficient: In a synchronous generator, the damping winding generates electromagnetic resistance to suppress rotor oscillation. The grid-type converter simulates this characteristic through an algorithm, which is called damping. 10. Overdamped constraint: In the parameter design of grid-type converters, in order to avoid excessively slow dynamic response or reduced energy efficiency of the system, an upper limit is set on the damping coefficient. 11. Phase margin constraint: The core indicator for evaluating the dynamic stability of a phase-locked loop (PLL), which determines whether the PLL will oscillate or lose lock under grid disturbances.

[0014] In existing technologies, frequency control methods in hybrid systems with grid-connected converters primarily rely on the grid-connected converters to provide frequency support, including the use of virtual synchronous machine control or droop control. Grid-connected converters, on the other hand, often employ additional virtual inertia or droop elements to provide a small amount of frequency support. However, in traditional frequency control methods, the control parameters of both grid-connected and grid-connected converters are mostly designed based on fixed scenarios, lacking adaptability to grid strength and actual operating conditions. Furthermore, existing frequency control methods typically use single-parameter configurations. While this approach can provide stability under most normal operating conditions, it cannot be fully implemented in complex and extreme grid environments, leading to problems such as frequency fluctuations and system instability.

[0015] To at least solve the above problems, please refer to Figure 1 This invention provides a frequency control method for a hybrid system of grid-connected converters, characterized by the following steps: Obtain the first control parameters of the grid-connected converter at the frequency response, and the second control parameters of the grid-connected converter at the frequency response; Based on the first control parameter and the second control parameter, an objective function is constructed with the goal of minimizing the frequency change rate of the hybrid system of grid-type converters. Solve the objective function to obtain the optimal solutions for the first control parameters and the second control parameters; Frequency control is performed on the hybrid system of the grid converter based on the optimal solution of the first control parameter and the second control parameter.

[0016] As described above, the beneficial effects of this invention are as follows: First, it obtains the first control parameters of the grid-connected converter in the hybrid system during frequency response, and second, it obtains the second control parameters of the grid-connected converter during frequency response. Based on the first and second control parameters, it constructs an objective function with the goal of minimizing the frequency change rate of the grid-connected hybrid system, and solves this objective function to obtain the optimal solutions for the first and second control parameters. Based on the optimal solutions, it performs frequency control on the grid-connected hybrid system. In this way, the control parameters can be adaptively adjusted according to the operating conditions of the grid-connected hybrid system, solving the frequency oscillation problem caused by complex interactions in the grid-connected hybrid system, and ensuring the stable and reliable operation of the power system.

[0017] Furthermore, based on the first control parameter and the second control parameter, an objective function is constructed to minimize the frequency change rate of the hybrid system of the grid-connected converter, including: The first control parameters include the phase-locked loop ratio, phase-locked loop integral coefficient, and quadrature-axis voltage of the grid-type converter; the second control parameters include the inertia and damping coefficient of the grid-type converter. The first angular frequency change rate of the grid-connected converter is calculated based on the phase-locked loop ratio, the phase-locked loop integral coefficient, and the quadrature-axis voltage. Calculate the second angular frequency change rate of the grid converter based on the inertia and the damping coefficient; Define a penalty term for the frequency change rate in a system with a grid-connected converter; An objective function is constructed with the goal of minimizing the sum of the first angular frequency change rate, the second angular frequency change rate, and the penalty term.

[0018] As described above, the frequency response of a grid-connected converter is related to the phase-locked loop (PLL) ratio, PLL integral coefficient, and quadrature-axis voltage, while the frequency response of a grid-connected converter is related to inertia and damping coefficient. Based on this, an objective function can be established to minimize the frequency change rate of the grid-connected AC system.

[0019] Furthermore, the objective function is specifically:

[0020] In the formula, λ1 represents the first weighting coefficient corresponding to the first rate of change of angular frequency, λ2 represents the second weighting coefficient corresponding to the second rate of change of angular frequency, and λ0 represents the penalty factor. K p Indicates the phase-locked loop ratio. K i This represents the integral coefficient of the phase-locked loop. u q Indicates quadrature-axis voltage. J This represents the inertia. D Indicates the damping coefficient. P ref This represents the reference value for active power. P e This represents the actual output value of active power. ω Represents angular frequency. ω 0 indicates the rated angular frequency. P cost This indicates a penalty.

[0021] Furthermore, the objective function for constructing a hybrid system of grid-connected converters, with the goal of minimizing the rate of frequency change, also includes: Define constraints for the objective function, including overdamping conditions for the damping coefficient and phase margin constraints for the phase-locked loop (PLL). The phase margin constraint for the PLL is that the ratio of the PLL proportional gain to the PLL integral coefficient is less than a preset time constant.

[0022] As described above, constraints are defined for the objective function, including overdamping conditions for the damping coefficient and phase margin constraints for the phase-locked loop. These constraints all consider the dynamic stability of the system. Therefore, by combining the objective function and the constraints, a complete computational model can be constructed, which is convenient for subsequent solving to obtain the optimal control parameters for frequency control.

[0023] Further, solving the objective function to obtain the optimal solutions for the first control parameters and the second control parameters includes: A population for initializing a swarm intelligence optimization algorithm is established, wherein each individual in the population contains a set of first control parameters and a set of second control parameters; Substitute each individual in the population into the objective function to calculate the fitness value of each individual; The optimal individual is determined from the population based on the fitness value, and the first control parameter and the second control parameter contained in the optimal individual are taken as the optimal solution.

[0024] As described above, the objective function is solved using a swarm intelligence optimization algorithm. The algorithm is used to perform global collaborative optimization of inertia, damping coefficient, and phase-locked loop proportional-integral parameters to ensure that the frequency change rate of the hybrid system with the grid-type converter is minimized when the load changes.

[0025] Please refer to Figure 2 Another embodiment of the present invention provides a frequency control terminal for a hybrid system of grid-connected converters, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the various steps of the frequency control method for a hybrid system of grid-connected converters described above.

[0026] The frequency control method and terminal for a hybrid system of grid-connected converters described above are applicable to solving the frequency oscillation problem caused by complex interactions in hybrid systems of grid-connected converters, ensuring the stable and reliable operation of the power system. The following specific implementation methods illustrate this: Embodiment 1 of the present invention is as follows: A frequency control method for a hybrid system of grid-connected converters is presented. Compared with traditional control methods, this embodiment can solve the frequency oscillation problem caused by complex interactions in the hybrid system of grid-connected converters, ensuring the stable and reliable operation of the power system. The following sections will introduce the angular frequency synchronization mechanisms of grid-connected and hybrid systems, and the frequency enhancement method based on intelligent algorithms.

[0027] Please refer to Figure 3 , Figure 3 This diagram illustrates the mechanism of voltage phase-angular frequency synchronization with grid-type control according to an embodiment of the present invention. Grid-type control typically employs a power-current cascaded control structure. The outer loop active power typically operates in maximum power point tracking mode, with a reactive power command of 0. The inner current loop tracks the current command output from the outer loop.

[0028] Network control structures often employ a synchronous rotating coordinate system (PLL). The principle is as follows: using the Park transformation (used to convert the AC quantities in the three-phase stationary coordinate system abc into the DC quantities in the two-phase rotating coordinate system dq) to extract the voltage vector at the PCC point (point of common coupling). V pcc The cross-axis (q-axis) component u qThe PI controller acts as a loop filter, filtering out harmonics and negative sequence voltage interference to obtain the PLL output frequency. ω PLL With PCC point actual frequency ω PCC The difference The integrator acts as a synchronous coordinate system transformation angle controller when At that time, the Park transformation angle is fixed. θ PLL Phase-locked control can be viewed as a control... θ PLL ,make u q Always track its reference value u q * The control process typically involves the Park transform oriented along the d-axis, i.e. u q * =0. The relationship between the rate of change of angular frequency and the voltage and phase-locked loop control parameters can be obtained as follows:

[0029] In the formula, K p and K i These are the proportional and integral coefficients of the phase-locked loop, respectively. ω ω is the angular frequency.

[0030] Please refer to Figure 4 , Figure 4 This diagram illustrates the mechanism of active power-angular frequency synchronization in grid-based control according to an embodiment of the present invention. Grid-based control typically employs a power-voltage-current cascaded control structure. Compared to grid-following control, a voltage loop is added to track the grid-connected point voltage amplitude output by the power loop control. V pcc * and phase θ PCC * Taking virtual synchronous machine control as an example for analysis, the relevant expressions for the active power-angular frequency synchronization mechanism are:

[0031] In the formula, J and D These are virtual inertia and damping coefficient, respectively. P ref and P e These are the active power reference value and the actual active power output value, respectively. δ The system power angle; ω0 indicates the rated angular frequency, which is 50*2π.

[0032] For a hybrid system with integrated grid control, the above analysis shows that the frequency change rate of the integrated grid system is related to the proportional-integral coefficient of the phase-locked loop and the q-axis voltage; while the frequency change rate of the hybrid grid system is related to the inertia and damping coefficient (the reference value of active power is the same as the actual value during stable operation). Based on this, an objective function can be established, and considering the constraints under normal operation, a complete objective function can be constructed. Then, an intelligent algorithm (using the Grey Wolf algorithm as an example here) is used to find the optimal solution for the control parameters, ensuring that the frequency change rate of the hybrid grid system is minimized when the load changes. Please refer to... Figure 1 A frequency control method for a hybrid system with a grid-connected converter includes the following steps: S1. Obtain the first control parameters of the grid-connected converter at the frequency response, and the second control parameters of the grid-connected converter at the frequency response.

[0033] Specifically, the first control parameters include the phase-locked loop ratio, phase-locked loop integral coefficient, and quadrature-axis voltage of the grid converter, while the second control parameters include the inertia and damping coefficient of the grid converter.

[0034] S2. Based on the first control parameter and the second control parameter, construct an objective function with the goal of minimizing the frequency change rate of the hybrid system of grid-type converters.

[0035] Specifically, the first angular frequency change rate of the grid-connected converter is calculated based on the phase-locked loop (PLL) ratio, PLL integral coefficient, and quadrature-axis voltage; the second angular frequency change rate of the grid-connected converter is calculated based on inertia and damping coefficient; a penalty term for the frequency change rate of the grid-connected converter hybrid system is defined; and an objective function is constructed with the goal of minimizing the sum of the first angular frequency change rate, the second angular frequency change rate, and the penalty term. The objective function is as follows:

[0036]

[0037] In the formula, λ1 represents the first weighting coefficient corresponding to the first rate of change of angular frequency, λ2 represents the second weighting coefficient corresponding to the second rate of change of angular frequency, and λ0 represents the penalty factor. K p Indicates the phase-locked loop ratio. K i This represents the integral coefficient of the phase-locked loop. u q Indicates quadrature-axis voltage. J This represents the inertia. D Indicates the damping coefficient. P ref This represents the reference value for active power. Pe This represents the actual output value of active power, ω0 represents the rated angular frequency, and ω represents the angular frequency. P cost This represents the penalty term. λ0 is typically a large value, such as 10. 4 ~10 6 .

[0038] Furthermore, constraints are defined for the objective function, including overdamping conditions for the damping coefficient and phase margin constraints for the phase-locked loop (PLL). The phase margin constraint for the PLL is that the ratio of the PLL proportional gain to the PLL integral coefficient is less than a preset time constant.

[0039] Specifically, set dynamic stability constraints: Overdamped condition D 2 >4 J ( P ref - P e ); Phase margin constraints K p / K i < T s , T s This is the system time constant.

[0040] Physical parameter constraints also need to be set: J >0, D >0, K p >0, K i >0.

[0041] S3. Solve the objective function to obtain the optimal solutions for the first control parameter and the second control parameter.

[0042] Specifically, the population for the swarm intelligence optimization algorithm is initialized, and each individual in the population contains a set of first control parameters and second control parameters; each individual in the population is substituted into the objective function to calculate the fitness value of each individual; the optimal individual is determined from the population based on the fitness value, and the first control parameters and second control parameters contained in the optimal individual are taken as the optimal solution.

[0043] In this embodiment, please refer to Figure 5 The swarm intelligence optimization process (using the Grey Wolf algorithm as an example in this embodiment) is as follows: S31. Initialize the gray wolf population Define the gray wolf population size N, the maximum number of iterations Maxlter, and the convergence factor a (initial value is usually 2, decreasing linearly to 0 with iterations). Set the parameter range as follows: J ∈[ J min ,J max ], D ∈[ D min ,D max ], K p ∈[ K pmin ,K pmax ], K i ∈[ K imin ,K imax ] Initialize the positions of N gray wolves within the above parameter range, with each gray wolf representing a set of parameters to be optimized (including...). J , D , K p , K i ).

[0044] S32. Calculate fitness value For each individual gray wolf (i.e., a set of parameters) J , D , K p , K i Substituting the values ​​into the objective function, we obtain the fitness value. In this converter parameter optimization problem, the objective function is to minimize the rate of frequency change, combined with a penalty term for stability constraints.

[0045] Based on fitness values, the top three are marked as leader wolves. α , β , δ , representing the current optimal, second-optimal, and third-optimal solutions, respectively. Other gray wolves update their positions based on the guidance of the leader wolf. The frequency change rate is dynamically calculated based on the actual system state.

[0046] S33, Iterative Update Process The gray wolf gradually surrounds the potential optimal solution by adjusting its position. In each iteration, according to... α , β , δ Update the position of each Gray Wolf X.

[0047] Calculate the current gray wolf and α , β , δ The distance between them is calculated using the following formula: D α =| C 1 X α - X |, D β =| C 2 X β - X |, D δ =| C 3 X δ - X | In the formula, X α , X β , X δ for α , β , δ The position, X is the current position of the gray wolf. C 1, C 2, C 3 is a random coefficient vector that simulates the randomness of gray wolves moving near their prey. This randomness simulates the uncertain and changing behavior that gray wolf packs may exhibit when tracking prey. The value of C is usually randomly generated between 0 and 2.

[0048] Location update based on Grey Wolf and α , β , δ The distance was used to simulate the gray wolf's estimation of the prey's location and corresponding movement during the hunt. The update formula is as follows:

[0049] In the formula, X new This is the new position for the Grey Wolves. A 1, A 2, A 3 is another set of dynamic coefficients that determine the intensity and direction of the gray wolf's movement toward its prey, affecting the tightness with which the wolf surrounds the prey. A typically starts at 2 and gradually decreases to 0 during iteration. When A is close to 0, the gray wolf pack tends to meticulously search for the optimal solution; when A is larger, the gray wolf pack performs a more extensive search in the solution space.

[0050] After the gray wolves updated their positions, the three best gray wolves were evaluated and became the new...α , β , δ .

[0051] S34. Repeat step S33 until the maximum number of iterations is reached or convergence occurs, i.e., the fitness value is less than the threshold. The optimal set is then obtained. J , D , K p , K i parameter.

[0052] S4. Frequency control is performed on the hybrid system of the grid converter based on the optimal solution of the first control parameter and the second control parameter.

[0053] Therefore, compared with traditional control methods, the frequency control method in this embodiment can adaptively adjust control parameters according to operating conditions to minimize the frequency change rate. Based on the influencing factors of frequency response under grid-connected operation mode, an optimization objective function is established. An improved gray wolf algorithm is used to globally and collaboratively optimize the virtual inertia, damping coefficient, and phase-locked loop proportional-integral parameters to minimize the frequency change rate and ensure the frequency stability and reliable operation of the power system.

[0054] Please refer to Figure 2 Embodiment two of the present invention is as follows: A frequency control terminal 1 for a grid-connected converter hybrid system includes a memory 2, a processor 3, and a computer program stored in the memory 2 and executable on the processor 3. When the processor 3 executes the computer program, it implements the various steps of the frequency control method for a grid-connected converter hybrid system according to Embodiment 1.

[0055] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent modifications made based on the content of the present invention specification and drawings, or direct or indirect applications in related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A frequency control method for a hybrid system of grid-connected converters, characterized in that, Including the following steps: Obtain the first control parameters of the grid-connected converter at the frequency response, and the second control parameters of the grid-connected converter at the frequency response; Based on the first control parameter and the second control parameter, an objective function is constructed with the goal of minimizing the frequency change rate of the hybrid system of grid-type converters. Solve the objective function to obtain the optimal solutions for the first control parameters and the second control parameters; Frequency control is performed on the hybrid system of the grid converter based on the optimal solution of the first control parameter and the second control parameter.

2. The frequency control method for a hybrid system of grid-connected converters according to claim 1, characterized in that, Based on the first control parameter and the second control parameter, an objective function is constructed to minimize the frequency change rate of the hybrid system of grid-connected converters, including: The first control parameters include the phase-locked loop ratio, phase-locked loop integral coefficient, and quadrature-axis voltage of the grid-type converter; the second control parameters include the inertia and damping coefficient of the grid-type converter. The first angular frequency change rate of the grid-connected converter is calculated based on the phase-locked loop ratio, the phase-locked loop integral coefficient, and the quadrature-axis voltage. Calculate the second angular frequency change rate of the grid converter based on the inertia and the damping coefficient; Define a penalty term for the frequency change rate in a system with a grid-connected converter; An objective function is constructed with the goal of minimizing the sum of the first angular frequency change rate, the second angular frequency change rate, and the penalty term.

3. The frequency control method for a hybrid system of grid-connected converters according to claim 2, characterized in that, The objective function is specifically: In the formula, λ1 represents the first weighting coefficient corresponding to the first rate of change of angular frequency, λ2 represents the second weighting coefficient corresponding to the second rate of change of angular frequency, and λ0 represents the penalty factor. K p Indicates the phase-locked loop ratio. K i This represents the integral coefficient of the phase-locked loop. u q Indicates quadrature-axis voltage. J This represents the inertia. D Indicates the damping coefficient. P ref This represents the reference value for active power. P e This represents the actual output value of active power, ω0 represents the rated angular frequency, and ω represents the angular frequency. P cost This indicates a penalty.

4. The frequency control method for a hybrid system of grid-connected converters according to claim 2, characterized in that, Constructing an objective function that minimizes the rate of frequency change in a hybrid system of grid-connected converters also includes: Define constraints for the objective function, including overdamping conditions for the damping coefficient and phase margin constraints for the phase-locked loop (PLL). The phase margin constraint for the PLL is that the ratio of the PLL proportional gain to the PLL integral coefficient is less than a preset time constant.

5. The frequency control method for a hybrid system of grid-connected converters according to claim 2, characterized in that, Solving the objective function to obtain the optimal solutions for the first control parameters and the second control parameters includes: A population for initializing a swarm intelligence optimization algorithm is established, wherein each individual in the population contains a set of first control parameters and a set of second control parameters; Substitute each individual in the population into the objective function to calculate the fitness value of each individual; The optimal individual is determined from the population based on the fitness value, and the first control parameter and the second control parameter contained in the optimal individual are taken as the optimal solution.

6. A frequency control terminal for a grid-connected converter hybrid system, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it performs the following steps: Obtain the first control parameters of the grid-connected converter at the frequency response, and the second control parameters of the grid-connected converter at the frequency response; Based on the first control parameter and the second control parameter, an objective function is constructed with the goal of minimizing the frequency change rate of the hybrid system of grid-type converters. Solve the objective function to obtain the optimal solutions for the first control parameters and the second control parameters; Frequency control is performed on the hybrid system of the grid converter based on the optimal solution of the first control parameter and the second control parameter.

7. The frequency control terminal for a hybrid grid converter system according to claim 6, characterized in that, Based on the first control parameter and the second control parameter, an objective function is constructed to minimize the frequency change rate of the hybrid system of grid-connected converters, including: The first control parameters include the phase-locked loop ratio, phase-locked loop integral coefficient, and quadrature-axis voltage of the grid-type converter; the second control parameters include the inertia and damping coefficient of the grid-type converter. The first angular frequency change rate of the grid-connected converter is calculated based on the phase-locked loop ratio, the phase-locked loop integral coefficient, and the quadrature-axis voltage. Calculate the second angular frequency change rate of the grid converter based on the inertia and the damping coefficient; Define a penalty term for the frequency change rate in a system with a grid-connected converter; An objective function is constructed with the goal of minimizing the sum of the first angular frequency change rate, the second angular frequency change rate, and the penalty term.

8. The frequency control terminal for a hybrid grid converter system according to claim 7, characterized in that, The objective function is specifically: In the formula, λ1 represents the first weighting coefficient corresponding to the first rate of change of angular frequency, λ2 represents the second weighting coefficient corresponding to the second rate of change of angular frequency, and λ0 represents the penalty factor. K p Indicates the phase-locked loop ratio. K i This represents the integral coefficient of the phase-locked loop. u q Indicates quadrature-axis voltage. J This represents the inertia. D Indicates the damping coefficient. P ref This represents the reference value for active power. P e This represents the actual output value of active power, ω0 represents the rated angular frequency, and ω represents the angular frequency. P cost This indicates a penalty.

9. The frequency control terminal for a hybrid system of grid-connected converters according to claim 7, characterized in that, Constructing an objective function that minimizes the rate of frequency change in a hybrid system of grid-connected converters also includes: Define constraints for the objective function, including overdamping conditions for the damping coefficient and phase margin constraints for the phase-locked loop (PLL). The phase margin constraint for the PLL is that the ratio of the PLL proportional gain to the PLL integral coefficient is less than a preset time constant.

10. The frequency control terminal for a hybrid grid converter system according to claim 7, characterized in that, Solving the objective function to obtain the optimal solutions for the first control parameters and the second control parameters includes: A population for initializing a swarm intelligence optimization algorithm is established, wherein each individual in the population contains a set of first control parameters and a set of second control parameters; Substitute each individual in the population into the objective function to calculate the fitness value of each individual; The optimal individual is determined from the population based on the fitness value, and the first control parameter and the second control parameter contained in the optimal individual are taken as the optimal solution.

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