Modeling method for representing typical network construction control active-frequency response characteristics

Abstract

The invention provides a modeling method for representing typical network construction control active-frequency response characteristics, and belongs to the technical field of power system automation and control, and the method comprises the steps: 1, obtaining key parameters of a preset parameter type of a circuit, and obtaining key parameters of a controller; 2, determining a power angle characteristic coefficient and an angular frequency base value; step 3, constructing a transfer function of a preset type based on the key parameters of the preset parameter type of the circuit, the key parameters of the preset type of the controller, the power angle characteristic coefficient and the angular frequency base value; 4, constructing a unified active power-frequency transfer function model in a general form, and meanwhile, determining a network construction type type parameter table; and step 5, determining a key value in the unified active-frequency transfer function model based on the network type parameter table, and further solving the unified active-frequency transfer function model. The relationship among the control parameters is visually obtained, and the workload can be greatly reduced when dynamic characteristics such as damping and inertia are analyzed.

Description

Technical Field

[0001] The present invention relates to the technical field of power system automation and control, and in particular to a modeling method for characterizing active power-frequency response characteristics of typical network control. Background Art

[0002] With the increasing complexity of power systems and the increasing proportion of new energy access, power system stability and control issues have received more and more attention. Active power-frequency control is an important part of power system stability control, and its control strategy and response characteristics have a significant impact on the overall system performance.

[0003] In the prior art, network control is usually studied through traditional active-frequency characteristic analysis models (e.g., based on simple linearization models or empirical modeling methods). Although these methods can describe the active-frequency relationship in certain specific cases, they have the following defects: first, the scope of application of the model is limited, and it is difficult to uniformly characterize the active-frequency response characteristics of different types of network control; second, traditional modeling methods are difficult to effectively integrate circuit parameters and controller parameters, and the model accuracy is insufficient; third, the existing models lack a general optimization strategy when optimizing the active-frequency characteristics, which limits the adaptability to complex systems.

[0004] Therefore, the present invention provides a modeling method for characterizing the active power-frequency response characteristics of a typical grid control. Summary of the invention

[0005] The present invention provides a modeling method for characterizing the active-frequency response characteristics of a typical network control, which is used to establish an active-frequency transfer function through Pf droop control, VSG control, and DC voltage matching control, and based on the characteristics of each transfer function, summarizes the consistency of several network type controls in mathematical models, and proposes a unified transfer function model. Based on this unified transfer function model, the relationship between various control parameters can be intuitively obtained, and the workload can also be greatly reduced when analyzing dynamic characteristics such as damping and inertia.

[0006] The present invention provides a modeling method for characterizing the active power-frequency response characteristics of a typical network control, comprising:

[0007] Step 1: Obtain key parameters of the preset parameter type of the circuit, and at the same time, obtain key parameters of the controller;

[0008] Step 2: Determine the power angle characteristic coefficient and the angular frequency base value based on the key parameters of the preset parameter type of the circuit and the key parameters of the preset type of the controller;

[0009] Step 3: constructing a transfer function of a preset type based on key parameters of a preset parameter type of the circuit, key parameters of a preset type of the controller, power angle characteristic coefficients, and angular frequency base values;

[0010] Step 4: construct a general unified active power-frequency transfer function model based on the preset type of transfer function, and at the same time, determine the network type parameter table;

[0011] Step 5: Determine the key values ​​in the unified active power-frequency transfer function model based on the network type parameter table, and then solve the unified active power-frequency transfer function model.

[0012] The present invention provides a modeling method for characterizing the active power-frequency response characteristics of a typical network control, obtaining key parameters of a preset parameter type of a circuit, and at the same time, obtaining key parameters of a controller, including:

[0013] Acquire key parameters of a first preset parameter type of the circuit based on a preset device technical document;

[0014] Determining key parameters of a second preset parameter type based on key parameters of a first preset parameter type for the circuit;

[0015] Determine the type of key parameters corresponding to each controller type based on a preset controller type and a preset type-parameter database;

[0016] The acquisition method of each type of key parameter is determined based on a preset parameter type-mode database, and then a number of key parameters corresponding to each controller type are determined.

[0017] The present invention provides a modeling method for characterizing the active power-frequency response characteristics of a typical network control, and the controller types include: Pf droop control, VSG control and DC voltage matching control.

[0018] The present invention provides a modeling method for characterizing the active power-frequency response characteristics of a typical network control, and constructs a transfer function of a preset type based on key parameters of a preset parameter type of a circuit, key parameters of a preset type of a controller, a power angle characteristic coefficient, and an angular frequency base value, including:

[0019] Based on the key parameters of the preset parameter type of the circuit, the key parameters of the preset type of the controller, the power characteristic coefficient and the angular frequency base value, the transfer functions of Pf droop control, VSG control and DC voltage matching control are constructed respectively.

[0020] The present invention provides a modeling method for characterizing the active power-frequency response characteristics of a typical network control, and constructs a general unified active power-frequency transfer function model based on a preset type of transfer function, including:

[0021] Perform structural analysis on the transfer functions of Pf droop control, VSG control and DC voltage matching control, and then determine the common transmission characteristics of the transfer function models of Pf droop control, VSG control and DC voltage matching control based on the structural analysis results;

[0022] A general unified active power-frequency transfer function model is determined based on the common transfer characteristics of the transfer function models of Pf droop control, VSG control and DC voltage matching control.

[0023] The present invention provides a modeling method for characterizing the active power-frequency response characteristics of a typical network control, and constructs transfer functions of Pf droop control, VSG control and DC voltage matching control based on key parameters of a preset parameter type of a circuit, key parameters of a preset type of a controller, power characteristic coefficients and angular frequency base values, including:

[0024] Based on the key parameters of the preset parameter type of the circuit, the key parameters of the preset type of the controller, the power characteristic coefficient, the angular frequency base value and the preset Pf droop characteristic expression, a small signal model of the Pf droop control is determined by a preset analysis method;

[0025] The small signal model of the Pf droop control is sorted out based on the preset first expression to determine the initial function of the Pf droop control;

[0026] The Pf droop control initial function is optimized based on the preset first optimization method, and then the Pf droop control initial transfer function is determined:

[0027]

[0028] Among them, ΔP1 e (s) is the disturbance component of active power corresponding to Pf droop control, Δω g (s) is the disturbance component of the power grid frequency, k s is the power angle characteristic coefficient, ω b is the reference frequency, s is the complex frequency variable in the preset analysis method, ω p K is the cutoff frequency corresponding to the preset first optimization method, p is the proportional control gain;

[0029] Determine a small signal model of the VSG control based on key parameters of a preset parameter type of the circuit, key parameters of a preset type of the controller, a power characteristic coefficient, an angular frequency base value, and a preset mathematical model of the VSG control;

[0030] Based on the preset second expression, the small signal model of VSG control is sorted out to determine the initial function of VSG control:

[0031]

[0032] Among them, ΔP2 e (s) is the disturbance component of active power corresponding to VSG control, J is the virtual moment of inertia, and D is the virtual damping coefficient;

[0033] Perform structural analysis and dual analysis on the converter and the synchronous machine, and then determine the corresponding matching relationship between the inverter DC voltage and the synchronous machine speed based on the structural analysis and dual analysis results;

[0034] Based on the corresponding matching relationship between the inverter DC voltage and the synchronous machine speed, the comparative analysis quantity is transformed from active power output to DC voltage output, and then the equations of the inverter DC side and AC side are determined in combination with the preset circuit relationship;

[0035] Determining an initial function of DC voltage matching control based on a preset analysis method;

[0036] The initial function of the voltage matching control is optimized based on the preset second optimization method, and then the transfer function of the DC voltage matching control is determined:

[0037]

[0038] Among them, ΔP3 e (s) is the disturbance component of active power corresponding to DC voltage matching control, C dc is the equivalent capacitance on the DC side, K dc is the virtual DC damping control gain, K ω is the damping coefficient.

[0039] 6. The present invention provides a modeling method for characterizing the active power-frequency response characteristics of a typical network control. The general form of the unified active power-frequency transfer function model is: Where ΔP e (s) is the disturbance component of active power in unified form, Δω g (s) is the disturbance component of the power grid frequency, k s is the power angle characteristic coefficient, ω b is the reference frequency, s is the complex frequency variable in the preset analysis method, A is the inertia coefficient, B is the damping coefficient, C is the constant coefficient, and B′ is the numerator damping coefficient.

[0040] The present invention provides a modeling method for characterizing the active power-frequency response characteristics of a typical network control, and determines a unified active power-frequency transfer function model, including:

[0041] Obtain and analyze the system's performance requirements, and determine the model optimization goals based on the analysis results;

[0042] Determine several key parameters to be optimized based on the model optimization goal and the preset goal-parameter data table;

[0043] Determine the corresponding parameter optimization method based on the preset target-method database, and optimize the key parameters to be optimized;

[0044] Verify the performance of the optimized unified active power-frequency transfer function model based on a preset optimization analysis method, and determine the performance coefficient of the optimized unified active power-frequency transfer function model;

[0045] The optimization is stopped when the optimized unified active power-frequency transfer function model performance coefficient is greater than the preset performance coefficient;

[0046] Then, the optimized unified active power-frequency transfer function model is determined as the final unified active power-frequency transfer function model.

[0047] The present invention provides a modeling method for characterizing the active power-frequency response characteristics of a typical network control, and the model optimization objectives include: improving the frequency regulation capability, enhancing the system damping, improving the dynamic response speed and improving the system stability.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] Active power-frequency transfer functions were established for Pf droop control, VSG control, and DC voltage matching control. Based on the characteristics of each transfer function, the consistency of several network-type controls in mathematical models was summarized, and a unified transfer function model was proposed. Based on this unified transfer function model, the relationship between various control parameters can be intuitively obtained, and the workload can be greatly reduced when analyzing dynamic characteristics such as damping and inertia. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0051] Figure 1 It is a flow chart of a modeling method for characterizing active power-frequency response characteristics of typical network control provided by an embodiment of the present invention. Figure 2 This is the control block diagram of the Pf droop part; Figure 3 It is the control block diagram of VSG; Figure 4 It is the block diagram of the optimized Pf droop control model; Figure 5 It is the optimized DC voltage matching control block diagram. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0053] Embodiment 1:

[0054] The embodiment of the present invention provides a modeling method for characterizing the active power-frequency response characteristics of a typical network control, such as Figure 1 As shown, including:

[0055] Step 1: Obtain key parameters of the preset parameter type of the circuit, and at the same time, obtain key parameters of the controller;

[0056] Step 2: Determine the power angle characteristic coefficient and the angular frequency base value based on the key parameters of the preset parameter type of the circuit and the key parameters of the preset type of the controller;

[0057] Step 3: constructing a transfer function of a preset type based on key parameters of a preset parameter type of the circuit, key parameters of a preset type of the controller, power angle characteristic coefficients, and angular frequency base values;

[0058] Step 4: construct a general unified active power-frequency transfer function model based on the preset type of transfer function, and at the same time, determine the network type parameter table;

[0059] Step 5: Determine the key values ​​in the unified active power-frequency transfer function model based on the network type parameter table, and then solve the unified active power-frequency transfer function model.

[0060] In this embodiment, the key parameters of the preset parameter type include line parameters (such as resistance, inductance, capacitance), node parameters (such as bus voltage), etc.;

[0061] In this embodiment, key parameters of the controller include control gain, time constant, filter cutoff frequency, etc.

[0062] In this embodiment, key values ​​in the unified active power-frequency transfer function model include: inertia coefficient, damping coefficient, constant coefficient and numerator damping coefficient.

[0063] In this embodiment, the active-frequency transfer function model is used to describe the relationship between the dynamic change of frequency and the change of active power in the power system. This model is mainly used to study the dynamic characteristics of the power system, such as frequency regulation, the impact of load fluctuations on frequency, and the design of primary frequency regulation and secondary frequency regulation control strategies;

[0064] In this embodiment, the grid-forming type parameter table is a key parameter set used to distinguish and define different grid-forming (GFM) control strategies. The function of this parameter table is to define specific control parameters according to the implementation methods of different grid-forming control strategies. The grid-forming type parameter table can be as follows:

[0065]

[0066] The beneficial effects of the above technical solution are as follows: by establishing active-frequency transfer functions for Pf droop control, VSG control, and DC voltage matching control, and based on the characteristics of each transfer function, the consistency of several network-type controls in mathematical models is summarized, and a unified transfer function model is proposed. Based on this unified transfer function model, the relationship between various control parameters can be intuitively obtained, and the workload can be greatly reduced when analyzing dynamic characteristics such as damping and inertia.

[0067] Embodiment 2:

[0068] The embodiment of the present invention provides a modeling method for characterizing the active power-frequency response characteristics of a typical network control, obtaining key parameters of a preset parameter type of a circuit, and at the same time, obtaining key parameters of a controller, including:

[0069] Acquire key parameters of a first preset parameter type of the circuit based on a preset device technical document;

[0070] Determining key parameters of a second preset parameter type based on key parameters of a first preset parameter type for the circuit;

[0071] Determine the type of key parameters corresponding to each controller type based on a preset controller type and a preset type-parameter database;

[0072] The acquisition method of each type of key parameter is determined based on a preset parameter type-mode database, and then a number of key parameters corresponding to each controller type are determined.

[0073] In this embodiment, the key parameters of the first preset parameter type include circuit parameters: output voltage and grid connection point voltage;

[0074] In this embodiment, the key parameter of the second preset parameter type is line impedance.

[0075] In this embodiment, the controller type and its parameters are: Pf droop control: droop coefficient, low-pass filter parameters, VSG control: virtual inertia, virtual damping, DC voltage matching control: DC voltage matching coefficient, virtual damping coefficient.

[0076] The beneficial effects of the above technical solution are: by obtaining the key parameters of the circuit and controller based on the equipment technical documents and the preset database, an automated and standardized parameter acquisition process is realized. According to the circuit and controller type, the key parameters and their acquisition methods are accurately determined, which improves the modeling efficiency and accuracy, simplifies the parameter collection process, ensures the adaptability of different controller types, and provides reliable data support for the modeling of the active-frequency response characteristics of the network control, and improves the flexibility and feasibility of system design and optimization.

[0077] Embodiment 3:

[0078] The embodiment of the present invention provides a modeling method for characterizing the active power-frequency response characteristics of a typical network control, and the controller types include: Pf droop control, VSG control and DC voltage matching control.

[0079] In this embodiment, Pf droop control is a control strategy based on the linear droop relationship of power-frequency (Pf) characteristics, which is used to realize the dynamic adjustment of power generation equipment to the grid frequency. In this control, the frequency deviation is proportional to the output active power, thereby ensuring the rationality of power distribution and the stability of grid frequency. The grid control is realized by simulating the primary frequency modulation characteristics and excitation characteristics of the synchronous generator. It is the simplest and most common grid control strategy, and the droop characteristic expression is:

[0080]

[0081] Among them, ω 0 is the initial value of the angular frequency, P e is the active power output of the grid-connected converter, P e is the active power reference value, the above parameters are all per unit values, ω B is the base value of angular frequency, take 100πrad / s, K p is the droop coefficient, δ is the output phase of the grid-side converter, P ref is the active power value expected to be output by the grid-connected converter, such as Figure 2 This is the control block diagram of the Pf droop part;

[0082] In this embodiment, VSG control realizes the inertial response and frequency support function of power electronic equipment by simulating the rotor inertia characteristics and damping characteristics of synchronous generators. This control strategy can enhance the dynamic performance and frequency stability of the power grid, and is particularly suitable for high-proportion new energy scenarios. VSG control realizes grid-type control by simulating the second-order equation of synchronous generator rotor motion. Compared with droop control, it can simulate the synchronous machine operation characteristics more accurately. The control block diagram of VSG is shown in the figure. Figure 3 As shown, the mathematical model of VSG control is:

[0083]

[0084] Among them, J is the virtual inertia, D is the virtual damping;

[0085] In this embodiment, DC voltage matching control is used for power distribution and frequency regulation on the DC side, and power sharing between different devices is achieved by controlling the DC bus voltage. This method is commonly used in DC microgrids and flexible DC transmission systems.

[0086] The beneficial effects of the above technical solution are as follows: by modeling three typical control types, namely Pf droop control, VSG control and DC voltage matching control, respectively, extracting and unifying their dynamic characteristics, effectively adapting to a variety of control strategies, simplifying the modeling process of active-frequency response characteristics, improving analysis and design efficiency, and providing theoretical support for optimizing system dynamic performance and stability.

[0087] Embodiment 4:

[0088] The embodiment of the present invention provides a modeling method for characterizing the active power-frequency response characteristics of a typical network control, and constructs a transfer function of a preset type based on key parameters of a preset parameter type of a circuit, key parameters of a preset type of a controller, a power angle characteristic coefficient, and an angular frequency base value, including:

[0089] Based on the key parameters of the preset parameter type of the circuit, the key parameters of the preset type of the controller, the power characteristic coefficient and the angular frequency base value, the transfer functions of Pf droop control, VSG control and DC voltage matching control are constructed respectively.

[0090] The beneficial effect of the above technical solution is: by constructing the transfer functions of Pf droop control, VSG control and DC voltage matching control, data support is provided for the subsequent extraction of their common transmission characteristics.

[0091] Embodiment 5:

[0092] The present invention provides a modeling method for characterizing the active power-frequency response characteristics of a typical network control, and constructs a general unified active power-frequency transfer function model based on a preset type of transfer function, including:

[0093] Perform structural analysis on the transfer functions of Pf droop control, VSG control and DC voltage matching control, and then determine the common transmission characteristics of the transfer function models of Pf droop control, VSG control and DC voltage matching control based on the structural analysis results;

[0094] A general form of a unified active-frequency transfer function model is determined based on the common transfer characteristics of the transfer function models of Pf droop control, VSG control, and DC voltage matching control. In this embodiment, the common transfer characteristics of the transfer function models of Pf droop control, VSG control, and DC voltage matching control are determined based on the structural analysis results. The structures of the three transfer functions are compared and analyzed, and the following common points can be found: First-order dynamic characteristics: Pf droop control and DC voltage matching control both have first-order dynamic characteristics, and the structure of the VSG control transfer function includes second-order inertial response characteristics, but in some cases it can be simplified to a first-order characteristic by appropriately adjusting the virtual damping coefficient and inertia. Each controller exhibits a dynamic adjustment relationship between input power and output frequency, and has a transfer characteristic dominated by gain and time constant.

[0095] The beneficial effects of the above technical solution are as follows: by constructing the transfer functions of Pf droop control, VSG control and DC voltage matching control, extracting their common transmission characteristics, and forming a unified active-frequency transfer function model, it is possible to uniformly describe the dynamic characteristics of different control strategies, improve the versatility and analysis efficiency of the model, and provide theoretical support for grid stability optimization.

[0096] Embodiment 6:

[0097] The embodiment of the present invention provides a modeling method for characterizing the active power-frequency response characteristics of a typical network control, and constructs the transfer functions of Pf droop control, VSG control and DC voltage matching control based on the key parameters of the preset parameter type of the circuit, the key parameters of the preset type of the controller, the power characteristic coefficient and the angular frequency base value, respectively, including:

[0098] Based on the key parameters of the preset parameter type of the circuit, the key parameters of the preset type of the controller, the power characteristic coefficient, the angular frequency base value and the preset Pf droop characteristic expression, a small signal model of the Pf droop control is determined by a preset analysis method;

[0099] The small signal model of the Pf droop control is sorted out based on the preset first expression to determine the initial function of the Pf droop control;

[0100] The Pf droop control initial function is optimized based on the preset first optimization method, and then the Pf droop control initial transfer function is determined:

[0101]

[0102] Among them, ΔP1 e (s) is the disturbance component of active power corresponding to Pf droop control, Δω g (s) is the disturbance component of the power grid frequency, k s is the power angle characteristic coefficient, ω b is the reference frequency, s is the complex frequency variable in the preset analysis method, ω p K is the cutoff frequency corresponding to the preset first optimization method, p is the proportional control gain;

[0103] Determine a small signal model of the VSG control based on key parameters of a preset parameter type of the circuit, key parameters of a preset type of the controller, a power characteristic coefficient, an angular frequency base value, and a preset mathematical model of the VSG control;

[0104] Based on the preset second expression, the small signal model of VSG control is sorted out to determine the initial function of VSG control:

[0105]

[0106] Among them, ΔP2 e (s) is the disturbance component of active power corresponding to VSG control, J is the virtual moment of inertia, and D is the virtual damping coefficient;

[0107] Perform structural analysis and dual analysis on the converter and the synchronous machine, and then determine the corresponding matching relationship between the inverter DC voltage and the synchronous machine speed based on the structural analysis and dual analysis results;

[0108] Based on the corresponding matching relationship between the inverter DC voltage and the synchronous machine speed, the comparative analysis quantity is transformed from active power output to DC voltage output, and then the equations of the inverter DC side and AC side are determined in combination with the preset circuit relationship;

[0109] Determining an initial function of DC voltage matching control based on a preset analysis method;

[0110] The initial function of the voltage matching control is optimized based on the preset second optimization method, and then the transfer function of the DC voltage matching control is determined:

[0111]

[0112] Among them, ΔP3 e (s) is the disturbance component of active power corresponding to DC voltage matching control, C dc is the equivalent capacitance on the DC side, K dc is the virtual DC damping control gain.

[0113] In this embodiment, the preset analysis method is to use Laplace transform and linear analysis.

[0114] In this embodiment, the first expression is preset as cos(δ 0 -θ 0 )≈1;

[0115] In this embodiment, the preset first optimization method is to add a low-pass filter at the front end of the droop coefficient. The optimized Pf droop control model block diagram is as follows: Figure 3 ;

[0116] In this embodiment, the second expression is preset as sΔθ(s)=ω B Δω g (s).

[0117] In this embodiment, the preset second optimization method is to add a virtual damping control in the control structure. The optimized DC voltage matching control block diagram is as follows: Figure 5 ;

[0118] The beneficial effects of the above technical solution are: by establishing small signal models of Pf droop control, VSG control and DC voltage matching control, their initial transfer functions are constructed respectively, and the transfer functions are finally determined by optimizing the preset optimization method, thereby improving the accuracy and applicability of the model and providing a reliable basis for dynamic performance analysis and control parameter optimization.

[0119] Embodiment 7:

[0120] The embodiment of the present invention provides a modeling method for characterizing the active power-frequency response characteristics of a typical network control. The general form of the unified active power-frequency transfer function model is: Where ΔP e (s) is the disturbance component of active power in unified form, Δω g (s) is the disturbance component of the power grid frequency, k s is the power angle characteristic coefficient, ω b is the reference frequency, s is the complex frequency variable in the preset analysis method, A is the inertia coefficient, B is the damping coefficient, C is the constant coefficient, and B′ is the numerator damping coefficient.

[0121] In this embodiment, the power angle characteristic coefficient is an important parameter used to describe the relationship between electrical power and power angle (usually the grid voltage phase angle difference) in the power grid. In the power system, it directly reflects the power transmission capacity and dynamic characteristics of the generator, inverter and other equipment in the system.

[0122] The beneficial effects of the above technical solution are: by establishing a general form of a unified active-frequency transfer function model, key parameters such as inertia coefficient, damping coefficient, power angle characteristic coefficient, etc. are comprehensively considered, and the common dynamic characteristics of Pf droop control, VSG control and DC voltage matching control are comprehensively characterized, thereby improving the versatility and adaptability of the model, providing a theoretical basis for system dynamic performance optimization and stability analysis, and simplifying the control strategy design.

[0123] Embodiment 8:

[0124] The embodiment of the present invention provides a modeling method for characterizing the active power-frequency response characteristics of a typical network control, and determines a unified active power-frequency transfer function model, including:

[0125] Obtain and analyze the system's performance requirements, and determine the model optimization goals based on the analysis results;

[0126] Determine several key parameters to be optimized based on the model optimization goal and the preset goal-parameter data table;

[0127] Determine the corresponding parameter optimization method based on the preset target-method database, and optimize the key parameters to be optimized;

[0128] Verify the performance of the optimized unified active power-frequency transfer function model based on a preset optimization analysis method, and determine the performance coefficient of the optimized unified active power-frequency transfer function model;

[0129] The optimization is stopped when the optimized unified active power-frequency transfer function model performance coefficient is greater than the preset performance coefficient;

[0130] Then, the optimized unified active power-frequency transfer function model is determined as the final unified active power-frequency transfer function model.

[0131] In this embodiment, the preset optimization analysis method includes: based on characteristic root distribution: adjusting parameters to distribute closed-loop poles at appropriate positions in the left half plane, based on frequency domain performance: adjusting parameters to make the amplitude frequency response of the transfer function meet the target (such as gain and phase margin), numerical optimization method: using genetic algorithms, particle swarm optimization algorithms or gradient descent algorithms to optimize the dynamic performance of the transfer function.

[0132] In this embodiment, the preset performance coefficient is an evaluation standard or indicator used to evaluate the performance of the model during the optimization process, which defines the minimum requirements that the system needs to meet in terms of performance requirements. Specifically, the preset performance coefficient is used to measure whether the optimized unified active power-frequency transfer function model meets the design objectives and system requirements, and is an important basis for determining whether the optimization process is terminated.

[0133] The beneficial effects of the above technical solution are: by setting optimization goals, combining the target-parameter data table with the target-method database, optimizing the key parameters of the unified active-frequency transfer function model, and verifying the model performance, the transfer function model can be iteratively optimized, significantly improving the dynamic performance and stability of the system, meeting the performance requirements of different network control strategies, and having high adaptability and practicality.

[0134] Embodiment 9:

[0135] An embodiment of the present invention provides a modeling method for characterizing the active power-frequency response characteristics of a typical grid control, and a model optimization target, including: the model optimization target is related to the frequency regulation capability, system damping, dynamic response speed and / or system stability.

[0136] In this embodiment, frequency regulation capability refers to the ability of the system to maintain grid frequency stability when facing active power disturbances. By optimizing control parameters (such as droop coefficient or inertia coefficient), the system can quickly restore the frequency to the target value or stabilize within a reasonable range when the load or power generation changes. Optimization method: adjust the active-frequency droop coefficient to increase the frequency response sensitivity; optimize the power angle characteristic coefficient to enhance power-frequency coupling. For example: the frequency regulation capability is weak. By increasing the damping coefficient of the virtual synchronous generator (VSG) or adopting improved droop control, the optimized model can significantly improve the system's ability to regulate frequency disturbances and avoid large frequency deviations;

[0137] In this embodiment, the system damping is to suppress frequency oscillations and avoid continuous oscillation or instability of the system after disturbance. Optimizing the damping coefficient can improve the oscillation attenuation capability of the system. The optimization method is: increasing the virtual damping coefficient; optimizing the DC side damping parameters in the DC voltage matching control. For example: in a microgrid operating in an island, low-frequency oscillations are prone to occur after frequency disturbances due to the small system inertia. By optimizing the damping coefficient of the VSG and increasing B from 0.05 to 0.1 (relative value), the oscillation frequency amplitude is reduced by 50%, significantly improving the system stability.

[0138] In this embodiment, the dynamic response speed is achieved by increasing the response speed, so that the system can recover the steady state faster and improve the dynamic performance. The optimization method is: reduce the inertia coefficient (virtual inertia parameter), increase the frequency response speed, optimize the droop coefficient, and make the frequency-power coupling relationship more sensitive; adjust the controller bandwidth to improve the control response speed. For example, in a power grid with large-scale new energy access, the frequency response speed is slow. By optimizing the virtual inertia parameter, the inertia coefficient A is reduced from 0.1 to 0.05 (relative value), and the frequency recovery time is reduced from 5 seconds to 3 seconds without losing stability;

[0139] In this embodiment, improving system stability is to ensure that the system can recover quickly under large disturbances or small signal disturbances, and prevent the system from entering an unstable state. The optimization method is: increase the inertia coefficient A to enhance the system's ability to resist large disturbances; optimize the power angle characteristic coefficient to ensure that the power-frequency relationship is reasonable; enhance the damping coefficient to avoid low-frequency oscillations. For example: in a weak power grid scenario, the system is prone to instability due to the low short-circuit ratio of the power grid. By optimizing the droop control and the inertia coefficient of the VSG, A is increased from 0.02 to 0.1, and the damping coefficient B is increased, ultimately achieving stable operation in a weak power grid environment.

[0140] The beneficial effects of the above technical solution are: by clarifying the model optimization objectives, including improving frequency regulation capability, enhancing system damping, improving dynamic response speed and improving system stability, the key parameters are optimized in a targeted manner, which significantly improves the dynamic performance and anti-disturbance capability of the model. This method is suitable for different control strategies, enhances the adaptability of the model and the stability of power grid operation, and provides theoretical support for the optimal design of complex power grids.

[0141] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A modeling method for characterizing the active power-frequency response characteristics of a typical network control, characterized in that: include: Step 1: Obtain key parameters of the preset parameter type of the circuit, and at the same time, obtain key parameters of the controller; Step 2: Determine the power angle characteristic coefficient and the angular frequency base value based on the key parameters of the preset parameter type of the circuit and the key parameters of the preset type of the controller; Step 3: constructing a transfer function of a preset type based on key parameters of a preset parameter type of the circuit, key parameters of a preset type of the controller, power angle characteristic coefficients, and angular frequency base values; Step 4: construct a general unified active power-frequency transfer function model based on the preset type of transfer function, and at the same time, determine the network type parameter table; Step 5: Determine the key values ​​in the unified active power-frequency transfer function model based on the network type parameter table, and then solve the unified active power-frequency transfer function model.

2. A modeling method for characterizing the active power-frequency response characteristics of a typical network control according to claim 1, characterized in that: Get the key parameters of the preset parameter type of the circuit, and at the same time, get the key parameters of the controller, including: Acquire key parameters of a first preset parameter type of the circuit based on a preset device technical document; Determining key parameters of a second preset parameter type based on key parameters of a first preset parameter type for the circuit; Determine the type of key parameters corresponding to each controller type based on a preset controller type and a preset type-parameter database; The acquisition method of each type of key parameter is determined based on a preset parameter type-mode database, and then a number of key parameters corresponding to each controller type are determined.

3. A modeling method for characterizing the active power-frequency response characteristics of a typical network control according to claim 2, characterized in that: Controller types, including: Pf droop control, VSG control and DC voltage matching control.

4. A modeling method for characterizing typical network control active power-frequency response characteristics according to claim 1, characterized in that: A transfer function of a preset type is constructed based on key parameters of a preset parameter type of the circuit, key parameters of a preset type of the controller, a power angle characteristic coefficient, and an angular frequency base value, including: Based on the key parameters of the preset parameter type of the circuit, the key parameters of the preset type of the controller, the power characteristic coefficient and the angular frequency base value, the transfer functions of Pf droop control, VSG control and DC voltage matching control are constructed respectively.

5. A modeling method for characterizing typical network control active power-frequency response characteristics according to claim 4, characterized in that: A general form of unified active power-frequency transfer function model is constructed based on a preset type of transfer function, including: Perform structural analysis on the transfer functions of Pf droop control, VSG control and DC voltage matching control, and then determine the common transmission characteristics of the transfer function models of Pf droop control, VSG control and DC voltage matching control based on the structural analysis results; A general unified active power-frequency transfer function model is determined based on the common transfer characteristics of the transfer function models of Pf droop control, VSG control and DC voltage matching control.

6. A modeling method for characterizing typical network control active power-frequency response characteristics according to claim 4, characterized in that: Based on the key parameters of the preset parameter type of the circuit, the key parameters of the preset type of the controller, the power characteristic coefficient and the angular frequency base value, the transfer functions of the Pf droop control, the VSG control and the DC voltage matching control are respectively constructed, including: Based on the key parameters of the preset parameter type of the circuit, the key parameters of the preset type of the controller, the power characteristic coefficient, the angular frequency base value and the preset Pf droop characteristic expression, a small signal model of the Pf droop control is determined by a preset analysis method; The small signal model of the Pf droop control is sorted out based on the preset first expression to determine the initial function of the Pf droop control; The Pf droop control initial function is optimized based on the preset first optimization method, and then the Pf droop control initial transfer function is determined: Among them, ΔP1 e (s) is the disturbance component of active power corresponding to Pf droop control, Δω g (s) is the disturbance component of the power grid frequency, k s is the power angle characteristic coefficient, ω b is the reference frequency, s is the complex frequency variable in the preset analysis method, ω p K is the cutoff frequency corresponding to the preset first optimization method, p is the proportional control gain; Determine a small signal model of the VSG control based on key parameters of a preset parameter type of the circuit, key parameters of a preset type of the controller, a power characteristic coefficient, an angular frequency base value, and a preset mathematical model of the VSG control; Based on the preset second expression, the small signal model of VSG control is sorted out to determine the initial function of VSG control: Among them, ΔP2 e (s) is the disturbance component of active power corresponding to VSG control, J is the virtual moment of inertia, and D is the virtual damping coefficient; Perform structural analysis and dual analysis on the converter and the synchronous machine, and then determine the corresponding matching relationship between the inverter DC voltage and the synchronous machine speed based on the structural analysis and dual analysis results; Based on the corresponding matching relationship between the inverter DC voltage and the synchronous machine speed, the comparative analysis quantity is transformed from active power output to DC voltage output, and then the equations of the inverter DC side and AC side are determined in combination with the preset circuit relationship; Determining an initial function of DC voltage matching control based on a preset analysis method; The initial function of the voltage matching control is optimized based on the preset second optimization method, and then the transfer function of the DC voltage matching control is determined: Among them, ΔP3 e (s) is the disturbance component of active power corresponding to DC voltage matching control, C dc is the equivalent capacitance on the DC side, K dc is the virtual DC damping control gain, K ω is the damping coefficient.

7. A modeling method for characterizing typical network control active power-frequency response characteristics according to claim 5, characterized in that: The general form of the unified active power-frequency transfer function model is: Where ΔP e (s) is the disturbance component of active power in unified form, Δω g (s) is the disturbance component of the power grid frequency, k s is the power angle characteristic coefficient, ω b is the reference frequency, s is the complex frequency variable in the preset analysis method, A is the inertia coefficient, B is the damping coefficient, C is the constant coefficient, and B′ is the numerator damping coefficient.

8. A modeling method for characterizing typical network control active power-frequency response characteristics according to claim 1, characterized in that: Determine a unified active power-frequency transfer function model, including: Obtain and analyze the system's performance requirements, and determine the model optimization goals based on the analysis results; Determine several key parameters to be optimized based on the model optimization goal and the preset goal-parameter data table; Determine the corresponding parameter optimization method based on the preset target-method database, and optimize the key parameters to be optimized; Verify the performance of the optimized unified active power-frequency transfer function model based on a preset optimization analysis method, and determine the performance coefficient of the optimized unified active power-frequency transfer function model; The optimization is stopped when the optimized unified active power-frequency transfer function model performance coefficient is greater than the preset performance coefficient; Then, the optimized unified active power-frequency transfer function model is determined as the final unified active power-frequency transfer function model.

9. A modeling method for characterizing typical network control active power-frequency response characteristics according to claim 7, characterized in that: Model optimization objectives are related to frequency regulation capability, system damping, dynamic response speed, and / or system stability.

Images