Method and device for optimizing and setting frequency modulation parameters of offshore wind power flexible direct output system

Abstract

The invention belongs to the field of electric power, and discloses a frequency modulation parameter optimization setting method and device for an offshore wind power flexible direct output system, and the method comprises the steps: building a frequency response analysis model of the offshore wind power flexible direct output system according to the control topology of the offshore wind power flexible direct output system, and calculating an equivalent frequency supporting capability transfer function of the system; drawing a time / frequency domain curve of the frequency supporting capability through an equivalent frequency supporting capability transfer function, and determining frequency modulation control parameters which influence the frequency supporting capability of the system; the system frequency modulation parameter optimizing and setting method based on the particle swarm optimization is provided according to the evaluation result of the equivalent frequency supporting capacity of the system from the double view angles of supporting strength and response speed. According to the method, the equivalent frequency supporting capacity of the offshore wind power flexible direct output system is calculated, a frequency modulation parameter optimization setting method based on a particle swarm algorithm is designed based on a frequency supporting capacity evaluation result, and comprehensive optimization of system frequency active supporting strength and response speed is achieved.

Description

Technical Field

[0001] This application relates to the field of power, and in particular to a method and apparatus for optimizing the frequency regulation parameters of an offshore wind power flexible direct transmission system. Background Technology

[0002] To meet the demand for large-scale offshore wind power transmission, flexible direct current (DC) transmission technology has gained widespread attention both domestically and internationally due to its advantages of strong controllability, large transmission capacity, and independent grid operation. Offshore wind power flexible DC transmission systems have become a key means of absorbing offshore wind power. However, the receiving-end converters of offshore wind power flexible DC transmission systems typically employ phase-locked synchronization, lacking the frequency support capability for the receiving-end power grid. To ensure the safe and stable frequency of the power system, offshore wind power flexible DC transmission systems need to employ inertia control strategies to enable them to possess a certain degree of frequency regulation capability.

[0003] However, while offshore wind power flexible DC transmission systems currently provide crucial power support to the power system, their role in frequency regulation still has room for improvement. Frequency regulation is central to power system stability, and with renewable energy sources like wind power gradually becoming the main power source, enhancing inertia support capabilities is particularly important. However, under grid frequency disturbances, the transient support power of offshore wind turbines and flexible DC transmission systems exhibits complex coupling, posing challenges to assessing the equivalent frequency support capability of offshore wind power flexible DC transmission systems. This makes it difficult to optimize the frequency support capability of offshore wind power flexible DC transmission systems based on sound reasoning. Therefore, it is urgent to assess the system's equivalent frequency support capability, further optimize the frequency regulation parameters of offshore wind power flexible DC transmission systems, fully explore the system's support potential, and improve the system's frequency support response speed and strength. Summary of the Invention

[0004] In view of this, embodiments of this application provide a method and apparatus for optimizing and setting the frequency regulation parameters of an offshore wind power flexible direct transmission system.

[0005] According to a first aspect of the embodiments of this application, a method for optimizing and tuning the frequency regulation parameters of an offshore wind power flexible direct transmission system is provided, characterized in that it includes: Based on the control topology of the offshore wind power flexible direct transmission system, a frequency response analysis model of the offshore wind power flexible direct transmission system is established. By analogy with the physical process of frequency modulation support of synchronous machine, the equivalent frequency support capability transfer function of the offshore wind power flexible direct transmission system is calculated. The time / frequency domain curves of the frequency support capability are plotted using the equivalent frequency support capability transfer function to determine the frequency regulation control parameters that affect the frequency support capability of the offshore wind power flexible direct transmission system. The frequency control parameters are optimized and tuned based on the particle swarm optimization algorithm. During the parameter optimization process, the optimization degree of the support strength and response speed of the offshore wind power flexible direct transmission system under the current parameters is comprehensively evaluated based on the time / frequency domain curve of the frequency support capability, which serves as the basis for iteration.

[0006] According to a second aspect of the embodiments of this application, a frequency regulation parameter optimization and tuning device for an offshore wind power flexible direct transmission system is provided, comprising: The equivalent frequency support capability transfer function calculation module is used to establish a frequency response analysis model of the offshore wind power flexible direct transmission system based on the control topology of the offshore wind power flexible direct transmission system, and calculate the equivalent frequency support capability transfer function of the offshore wind power flexible direct transmission system by analogy with the physical process of synchronous machine frequency modulation support. The frequency modulation control parameter selection module is used to draw the time / frequency domain curve of the frequency support capability through the equivalent frequency support capability transfer function, and to determine the frequency modulation control parameters that affect the frequency support capability of the offshore wind power flexible direct transmission system. The frequency modulation control parameter optimization module is used to optimize and tune the frequency modulation control parameters based on the particle swarm optimization algorithm. During the parameter optimization process, the optimization degree of the support strength and response speed of the offshore wind power flexible direct transmission system under the current parameters is comprehensively evaluated based on the time / frequency domain curve of the frequency support capability, which serves as the basis for iteration.

[0007] According to a third aspect of the embodiments of this application, an electronic device is provided, comprising: processor; Memory used to store processor-executable instructions; The processor implements the steps of the method as described in the first aspect by running the executable instructions.

[0008] According to a fourth aspect of the embodiments of this application, a computer-readable storage medium is provided that stores computer instructions thereon, which, when executed by a processor, implement the steps of the method as described in the first aspect.

[0009] The technical solutions provided by the embodiments of this application may include the following beneficial effects: As can be seen from the above embodiments, this application establishes a frequency response analysis model for the offshore wind power flexible direct transmission system based on the perspective of internal potential equivalence. It analyzes the power transfer path by analogy with a synchronous machine and derives the system's equivalent frequency support capability. Based on the quantitative evaluation results, the frequency regulation control parameters affecting the frequency support capability of the offshore wind power flexible direct transmission system are determined through time / frequency domain curves. Furthermore, focusing on both support strength and response speed, a system frequency regulation parameter optimization and tuning method based on the particle swarm optimization algorithm is proposed, overcoming the difficulties in evaluating the frequency support effect of the offshore wind power flexible direct transmission system and the lack of sufficient basis for parameter tuning. By optimizing the system frequency regulation parameters, this application fully explores the support potential of the offshore wind power flexible direct transmission system and comprehensively improves the system's frequency support response speed and strength.

[0010] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0011] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0012] Figure 1 This is a flowchart of an exemplary embodiment of a method for optimizing the frequency regulation parameters of an offshore wind power flexible direct transmission system.

[0013] Figure 2 This is a schematic diagram of the topology of an offshore wind power flexible direct transmission system provided in an exemplary embodiment.

[0014] Figure 3 This is a schematic diagram of a frequency response analysis model for an offshore wind power flexible direct transmission system provided in an exemplary embodiment.

[0015] Figure 4 This is a schematic diagram of an exemplary embodiment of a method for calculating the time-domain equivalent frequency support capability of an offshore wind power flexible direct transmission system.

[0016] Figure 5 This is a schematic diagram of the time / frequency domain curve of an offshore wind power flexible direct transmission system provided in an exemplary embodiment.

[0017] Figure 6 This is a flowchart of parameter optimization tuning for an offshore wind power flexible direct transmission system based on particle swarm optimization algorithm, provided as an exemplary embodiment.

[0018] Figure 7 This is a schematic diagram illustrating the comparison of the equivalent inertial time constant before and after optimization of an offshore wind power flexible direct transmission system, provided by an exemplary embodiment.

[0019] Figure 8 This is a block diagram of a frequency regulation parameter optimization and tuning device for an offshore wind power flexible direct transmission system, provided in an exemplary embodiment. Detailed Implementation

[0020] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0021] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0022] It should be understood that although the terms first, second, third, etc., may be used in this application to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0023] Figure 1 This is a flowchart illustrating a method for optimizing the frequency regulation parameters of an offshore wind power flexible direct transmission system according to an exemplary embodiment, such as... Figure 1 As shown, the method may include the following steps: S1: Based on the control topology of the offshore wind power flexible direct transmission system, establish a frequency response analysis model of the offshore wind power flexible direct transmission system, and calculate the equivalent frequency support capability transfer function of the offshore wind power flexible direct transmission system by analogy with the physical process of synchronous machine frequency modulation support. Specifically, Figure 2 This is a schematic diagram of the topology of an offshore wind power flexible DC transmission system provided in an exemplary embodiment. The offshore wind power flexible DC transmission system includes an offshore wind farm and a flexible DC transmission system. The offshore wind farm includes a turbine-side converter and a grid-side converter, and the flexible DC transmission system includes a receiving-end converter and a sending-end converter. The frequency response analysis model of the offshore wind power flexible DC transmission system includes: a frequency response analysis model of the offshore wind farm and a frequency response analysis model of the flexible DC transmission system. Taking into account the speed control of the offshore wind turbine-side converter, the constant DC voltage control of the grid-side converter, and additional... df / dt Virtual inertia control can yield frequency response analysis models for offshore wind farms, such as... Figure 3 As shown in the dashed diagram, the frequency response analysis model of the offshore wind farm can be described as follows: ; in, s The Laplace operator is used, where Δ represents the small semaphore of the variable. P e,OWF The active power output of offshore wind power. pll For the phase-locked loop phase of the grid-side converter, G OWF ( s ) is ∆ P e,OWF With ∆ pll The transfer function between them.

[0024] The G OWF ( s This can be represented as: ; The expressions for each item are as follows: ; ; Similar to the frequency response modeling of offshore wind farms, a frequency response analysis model for flexible DC transmission systems is established, such as... Figure 3 As shown in the solid line diagram. Since frequency support is typically a second-level process, belonging to the electromechanical time scale, and therefore... Figure 2 It is known that the deviation between the phase-locked frequency (PLL) of the grid-side converter and the receiving-end flexible DC converter in an offshore wind farm originates from the amplitude / frequency control of the sending-end flexible DC converter and the constant DC voltage control of the receiving-end flexible DC converter. The bandwidth of these two controls is approximately 10Hz, and the resulting delay can be ignored on the electromechanical time scale. Therefore, the PLL of the grid-side converter and the receiving-end flexible DC converter can be considered consistent. Consequently, the phase deviation of the grid-side converter's PLL is consistent with the phase deviation of the receiving-end flexible DC converter. Therefore, a complete frequency response analysis model for the offshore wind power flexible DC transmission system can be established by combining the flexible DC transmission frequency response analysis model and the offshore wind farm frequency response analysis model. Figure 3 As shown.

[0025] like Figure 3 As shown, a frequency response analysis model considering a flexible DC transmission system is presented, combined with the transfer function of an offshore wind farm. G OWF ( s The frequency response analysis model of the offshore wind power flexible direct transmission system is as follows: ; in, ; ; in, P e Output active power to the offshore wind power flexible direct transmission system. ctrl The power control angle is the internal potential. E For the phase of the internal potential of the receiving-end flexible DC converter, G ctrl1 , G ctrl2 For Δ P e With Δ ctrl The transfer function between them G pll1 , G pll2 For Δ P e With Δ pll The transfer function between them G pll ( s ) is the transfer function of the phase-locked loop. G 1( s )- G 6( s ) is an intermediate transfer function used for simplification. E 0 represents the steady-state value of the internal potential. U t0 This is the steady-state value of the terminal voltage. X f For filter reactance, C It is a DC capacitor. U dc0 This represents the steady-state value of the DC line voltage. k p,dc This refers to the proportional gain of the DC voltage controller. k i,dc The integral coefficient of the DC voltage controller. k p,pll This is the proportional gain of the phase-locked loop. k i,pll The integral coefficients of the phase-locked loop are... K 1 represents the droop coefficient of the receiving-end converter.

[0026] In one embodiment, based on the frequency response analysis model of the offshore wind power flexible direct transmission system, the transfer function of the equivalent frequency support capability of the offshore wind power flexible direct transmission system is calculated as follows: ; in, 0 represents the steady-state value of the angular velocity of the internal potential of the receiving-end flexible DC converter. J total ( s ) is the transfer function of the equivalent frequency support capability of the sea breeze flexible straight system.

[0027] By analogy with the physical process of frequency modulation response of a synchronous machine, the frequency response process of the offshore wind power flexible direct transmission system is decomposed into two parts: the flexible direct transmission system and the offshore wind power. By analogy with the inertial response of a synchronous machine and the primary frequency modulation process, the equivalent relationship between the two is explored, and the equivalent frequency support capability of the offshore wind power flexible direct transmission system is accurately assessed.

[0028] S2: Plot the time / frequency domain curve of the frequency support capability using the equivalent frequency support capability transfer function, and determine the frequency regulation control parameters that affect the frequency support capability of the offshore wind power flexible direct transmission system; Specifically, based on the equivalent frequency support capability transfer function, the frequency support capability Bode plot can be directly drawn, such as... Figure 5 As shown in (a) of the diagram. The larger the amplitude of the equivalent frequency support capability transfer function, the greater the system inertia, and the stronger its ability to generate active power during the frequency response process. The more the phase leads in the phase-frequency curve, the faster the system's response speed.

[0029] according to Figure 4 The time-domain equivalent frequency support capability calculation method shown assumes the existence of a value of f r For a ramp-shaped frequency disturbance, the steady-state angular velocity is calculated as the product of the angular velocity steady-state value and the rate of change of angular velocity. Since the frequency disturbance is ramp-shaped, the rate of change of angular velocity is constant. A step input of the corresponding magnitude is given to the equivalent frequency support capability transfer function, and the resulting step response is the output active power. The equivalent frequency support capability is further calculated as follows: ; in, J ( t This refers to the time-domain equivalent frequency support capability. t For time, P in To input active power for offshore wind power, P e Output active power to the offshore wind power flexible direct transmission system. The angular velocity of the internal potential of the receiving-end flexible DC converter.

[0030] according to Figure 4 The time-domain equivalent frequency support capability calculation method shown can yield the time-domain curve of the equivalent frequency support capability, as shown below. Figure 5 As shown in (b) above. Frequency support capability and response speed are key indicators for evaluating frequency response characteristics. Based on the time / frequency domain curve of equivalent frequency support capability, the changes in equivalent frequency support capability and response speed under different control parameter variations are compared to determine the frequency modulation control parameters that affect the frequency support capability of the offshore wind power flexible direct transmission system. The frequency modulation control parameters may include the phase-locked loop proportional coefficient. k p,pll Integral coefficientk i,pll Speed ​​control loop proportional coefficient k p,w Integral coefficient k i,w DC voltage control loop proportional coefficient k p,dc Integral coefficient k i,dc Virtual inertia control coefficient K f Low-pass filter time constant T f droop coefficient of receiving-end converter K 1.

[0031] Based on the evaluation results of the equivalent frequency support capability, time / frequency domain curves of the equivalent frequency support capability of the offshore wind power flexible direct transmission system were plotted. The time / frequency domain characteristics of the equivalent support capability can be analyzed intuitively. The influence of frequency regulation control parameters on the frequency support capability of the offshore wind power flexible direct transmission system can be evaluated from the aspects of frequency support capability magnitude and response speed. At the same time, the influence law of frequency regulation control parameters on equivalent inertia can be clarified.

[0032] S3: The frequency control parameters are optimized and tuned based on the particle swarm optimization algorithm. During the parameter iterative optimization process, the optimization degree of the support strength and response speed of the offshore wind power flexible direct transmission system under the current parameters is comprehensively evaluated based on the time / frequency domain curve of the frequency support capability, which serves as the basis for iteration. Specifically, the fitness function FF of the particle swarm optimization algorithm is: ; in, J norm To normalize the amplitude of the low-frequency band equivalent frequency support capability, T norm To normalize the system response time, The weighting coefficients for the system's frequency support capability and magnitude. This is the weighting coefficient for the system response time.

[0033] Since the equivalent frequency support capability amplitude and system response time in the low-frequency band have different dimensions, in order to avoid the large numerical value of the feature dominating the particle swarm algorithm iteration, normalization is used to scale them to the same scale.

[0034] The normalized low-frequency band equivalent frequency support capability amplitude is calculated through the equivalent frequency support capability frequency domain curve and is used to evaluate the support strength of the equivalent frequency support capability. The specific calculation formula is as follows: ; in, J minThis represents the minimum integral average value of the amplitude of the transfer function for the system's equivalent frequency support capability. J max This is the maximum value of the integral average of the amplitude of the transfer function for the system's equivalent frequency support capability.

[0035] The normalized system response time is calculated using the equivalent frequency support capability time-domain curve and is used to evaluate the equivalent frequency support response speed. The specific calculation formula is as follows: ; in, t 0.1 The time required for the system's equivalent frequency support capability to rise from 0 to 10% of its peak value. t 0.9 The time required for the system's equivalent frequency support capability to rise from 0 to 90% of its peak value. T min This represents the minimum system response time. T max This represents the maximum system response time.

[0036] Optionally, by introducing a penalty term for the sum of squares of the second derivative to suppress excessive fluctuations in the curve during the optimization process, the equivalent frequency support capability curve can be made smoother, and the system can be made more stable.

[0037] Since the equivalent frequency support capability time-domain curve can intuitively reflect the fluctuation of the equivalent frequency support capability when the system is unstable, the second derivative squared penalty term is calculated through the equivalent frequency support capability time-domain curve. The second derivative is approximated using the second-order difference, and the specific calculation formula is as follows:

[0038] in, for t i The second derivative value of the time-domain equivalent frequency support capability at time t. J ( t i )for t i The ability to support the time-domain equivalent frequency at any given moment.

[0039] The penalty term for the sum of squares of the second derivative is:

[0040] in, N This represents the number of sample points.

[0041] After adding the second derivative sum of squares penalty term, the fitness function is modified as follows: ; in, λ is the weighting coefficient of the second derivative squared sum penalty term.

[0042] Based on the equivalent frequency support capability of the sea breeze flexible system J total The time / frequency domain curves of (s) and the particle swarm optimization algorithm, and the frequency modulation control parameter optimization tuning method proposed in this invention are as follows: Figure 6 As shown, the specific steps are as follows: First, initialize the particle swarm parameters, including particle swarm size / dimension, number of iterations, inertia weight, position / velocity of each particle, etc.; second, calculate the fitness function and determine whether it is the optimal value within the iteration range. If not, update the particle swarm parameters according to the current fitness function and repeat the iteration process; finally, output the optimal parameters within the iteration range.

[0043] The conventional and optimized parameters of the offshore wind power flexible direct transmission system are shown in Table 1.

[0044] Table 1. Conventional and optimized parameters of offshore wind power flexible direct transmission system:

[0045] Specifically, according to Chinese power grid standards, the inertial time constant of wind turbines connected to the grid must not be less than 8 seconds. The frequency regulation parameters of the offshore wind-powered flexible DC transmission system calculated accordingly can be considered as the currently accepted conventional control parameters in the industry, as shown in the second column of Table 1. Based on the proposed method for optimizing the frequency regulation parameters of the offshore wind power flexible DC transmission system, the optimized control parameters can be calculated, as shown in the third column of Table 1.

[0046] The equivalent inertia comparison results of the sea breeze flexible straightening system under normal and optimized control parameters are as follows: Figure 7 As shown, the maximum equivalent inertial time constant of the system under normal parameters is approximately 8 seconds, which meets the power grid standard; the optimized system has a faster frequency response and improved support strength.

[0047] A frequency tuning parameter optimization method based on particle swarm optimization algorithm was designed. The time / frequency domain curves of the equivalent frequency support capability of the offshore wind power flexible direct transmission system can intuitively reflect the effect of parameter optimization tuning. It can be effectively used as the basis for iterative optimization of the particle swarm optimization algorithm. Based on this, the support potential of the offshore wind power flexible direct transmission system is fully explored, and the comprehensive optimization of system inertia support strength and response speed is achieved.

[0048] As described in the above embodiments, this application establishes a frequency response analysis model for the offshore wind power flexible direct transmission system from the perspective of internal potential equivalence. It analyzes the power transfer path by analogy with a synchronous machine and derives the system's equivalent frequency support capability. Based on the quantitative evaluation results, the frequency regulation control parameters affecting the frequency support capability of the offshore wind power flexible direct transmission system are determined through time / frequency domain curves. Furthermore, focusing on both support strength and response speed, a system frequency regulation parameter optimization and tuning method based on the particle swarm optimization algorithm is proposed, overcoming the difficulties in evaluating the frequency support effect of the offshore wind power flexible direct transmission system and the lack of sufficient basis for parameter tuning. By optimizing the system frequency regulation parameters, this application fully explores the support potential of the offshore wind power flexible direct transmission system and comprehensively improves the system's frequency support response speed and strength.

[0049] Corresponding to the aforementioned embodiments of the frequency regulation parameter optimization and tuning method for offshore wind power flexible direct transmission systems, this application also provides embodiments of the frequency regulation parameter optimization and tuning device for offshore wind power flexible direct transmission systems.

[0050] Figure 8 This is a block diagram illustrating a frequency regulation parameter optimization and tuning device for an offshore wind power flexible direct transmission system, according to an exemplary embodiment. (Refer to...) Figure 8 The device includes: The equivalent frequency support capability transfer function calculation module 1 is used to establish a frequency response analysis model of the offshore wind power flexible direct transmission system based on the control topology of the offshore wind power flexible direct transmission system, and to calculate the equivalent frequency support capability transfer function of the offshore wind power flexible direct transmission system by analogy with the physical process of frequency modulation support of the synchronous machine. Frequency modulation control parameter selection module 2 is used to draw the time / frequency domain curve of frequency support capability through the equivalent frequency support capability transfer function, and determine the frequency modulation control parameters that affect the frequency support capability of the offshore wind power flexible direct transmission system. The frequency modulation control parameter optimization module 3 is used to optimize and tune the frequency modulation control parameters based on the particle swarm algorithm. During the parameter optimization process, the optimization degree of the support strength and response speed of the offshore wind power flexible direct transmission system under the current parameters is comprehensively evaluated based on the time / frequency domain curve of the frequency support capability, which serves as the basis for iteration.

[0051] Regarding the apparatus in the above embodiments, the specific manner in which each module performs its operation has been described in detail in the embodiments related to the method, and will not be elaborated upon here.

[0052] For the device embodiments, since they basically correspond to the method embodiments, the relevant parts can be referred to in the description of the method embodiments. The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this application according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0053] Accordingly, this application also provides an electronic device, including: one or more processors; a memory for storing one or more programs; when the one or more programs are executed by the one or more processors, the one or more processors implement the frequency regulation parameter optimization tuning method of the offshore wind power flexible direct transmission system as described above.

[0054] Accordingly, this application also provides a computer-readable storage medium storing computer instructions that, when executed by a processor, implement the frequency regulation parameter optimization tuning method for the offshore wind power flexible direct transmission system as described above.

[0055] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and embodiments are to be considered exemplary only, and the true scope and spirit of this application are indicated by the claims.

[0056] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A method for optimizing and tuning the frequency regulation parameters of an offshore wind power flexible direct transmission system, characterized in that, include: Based on the control topology of the offshore wind power flexible direct transmission system, a frequency response analysis model of the offshore wind power flexible direct transmission system is established. By analogy with the physical process of frequency modulation support of synchronous machine, the equivalent frequency support capability transfer function of the offshore wind power flexible direct transmission system is calculated. The time / frequency domain curves of the frequency support capability are plotted using the equivalent frequency support capability transfer function to determine the frequency regulation control parameters that affect the frequency support capability of the offshore wind power flexible direct transmission system. The frequency control parameters are optimized and tuned based on the particle swarm optimization algorithm. During the parameter optimization process, the optimization degree of the support strength and response speed of the offshore wind power flexible direct transmission system under the current parameters is comprehensively evaluated based on the time / frequency domain curve of the frequency support capability, which serves as the basis for iteration.

2. The method according to claim 1, characterized in that, The frequency response analysis model of the offshore wind power flexible direct transmission system is as follows: ； in, ； ； in, s The Laplace operator is used, where Δ represents the small semaphore of the variable. P e Output active power to the offshore wind power flexible direct transmission system. P e,OWF The active power output of offshore wind power. ctrl The power control angle is the internal potential. pll For the phase-locked loop phase of the grid-side converter, E For the phase of the internal potential of the receiving-end flexible DC converter, G ctrl1 , G ctrl2 For Δ P e With Δ ctrl The transfer function between them G pll1 , G pll2 For Δ P e With Δ pll The transfer function between them G OWF ( s ) is Δ P e,OWF With Δ pll The transfer function between them G pll ( s ) is the transfer function of the phase-locked loop. G 1( s )- G 6( s ) is an intermediate transfer function used for simplification. E 0 represents the steady-state value of the internal potential. U t0 This is the steady-state value of the terminal voltage. X f For filter reactance, C It is a DC capacitor. U dc0 This represents the steady-state value of the DC line voltage. k p,dc This refers to the proportional gain of the DC voltage controller. k i,dc The integral coefficient of the DC voltage controller. k p,pll This is the proportional gain of the phase-locked loop. k i,pll The integral coefficients of the phase-locked loop are... K 1 represents the droop coefficient of the receiving-end converter.

3. The method according to claim 2, characterized in that, The equivalent frequency support capability transfer function is: ； in, For the internal potential angular velocity of the DC-DC converter, J total ( s ) is the transfer function of the equivalent frequency support capability of the sea breeze flexible straight system.

4. The method according to claim 1, characterized in that, By plotting the time / frequency domain curves of the frequency support capability using the equivalent frequency support capability transfer function, the frequency regulation control parameters that affect the frequency support capability of the offshore wind power flexible direct transmission system are determined, including: Based on the equivalent frequency support capability transfer function, the frequency support capability Bode plot, i.e. the frequency domain curve of the equivalent frequency support capability, is directly plotted. Given a step input to the equivalent frequency support capability transfer function, the resulting step response is the output active power, and then the time-domain equivalent frequency support capability is calculated. Draw the time-domain curve of the equivalent frequency support capability based on the time-domain equivalent frequency support capability; Based on the frequency domain curve and time domain curve of the equivalent frequency support capability, determine the frequency modulation control parameters that affect the equivalent frequency support capability.

5. The method according to claim 1, characterized in that, The time-domain equivalent frequency support capability is calculated using the following formula: ； in, J ( t This refers to the time-domain equivalent frequency support capability. t For time, P in To input active power for offshore wind power, The angular velocity of the internal potential of the receiving-end flexible DC converter.

6. The method according to claim 1, characterized in that, The fitness function of the particle swarm optimization algorithm is: ； In the formula, is the fitness function. The weighting coefficients for the system's frequency support capability and magnitude. J norm To normalize the amplitude of the low-frequency band equivalent frequency support capability, This is a weighting coefficient for the system response time. T norm To normalize the system response time, λ The weighting coefficients for the second derivative squared sum penalty term; M This is a penalty term for the sum of squares of the second derivative.

7. The method according to claim 6, characterized in that, The expression for the second derivative sum of squares penalty term is as follows: ； in, N The number of sample points; ； in, for t i The second derivative value of the time-domain equivalent frequency support capability at time t. J ( t i )for t i The ability to support the time-domain equivalent frequency at any given moment.

8. A frequency regulation parameter optimization and tuning device for an offshore wind power flexible direct transmission system, characterized in that, include: The equivalent frequency support capability transfer function calculation module is used to establish a frequency response analysis model of the offshore wind power flexible direct transmission system based on the control topology of the offshore wind power flexible direct transmission system, and calculate the equivalent frequency support capability transfer function of the offshore wind power flexible direct transmission system by analogy with the physical process of synchronous machine frequency modulation support. The frequency modulation control parameter selection module is used to draw the time / frequency domain curve of the frequency support capability through the equivalent frequency support capability transfer function, and to determine the frequency modulation control parameters that affect the frequency support capability of the offshore wind power flexible direct transmission system. The frequency modulation control parameter optimization module is used to optimize and tune the frequency modulation control parameters based on the particle swarm optimization algorithm. During the parameter optimization process, the optimization degree of the support strength and response speed of the offshore wind power flexible direct transmission system under the current parameters is comprehensively evaluated based on the time / frequency domain curve of the frequency support capability, which serves as the basis for iteration.

9. An electronic device, characterized in that, include: processor; Memory used to store processor-executable instructions; The processor implements the steps of the method as described in any one of claims 1-7 by running the executable instructions.

10. A computer-readable storage medium storing computer instructions thereon, characterized in that, When executed by the processor, this instruction implements the steps of the method as described in any one of claims 1-7.

Images