Optimal configuration method of multi-point network type converter satisfying synchronous support capability requirement

Abstract

The application discloses a multi-point network configuration type converter optimal configuration method meeting synchronous support capability demand, relates to the field of power system planning, and comprises the following steps: determining the quick frequency response capability and frequency modulation performance requirement of the network configuration converter; establishing an optimal configuration model meeting the synchronous support capability demand, and constructing a target function based on the minimum conversion cost of the network configuration type converter; according to the performance requirement of the new energy power station, setting a constraint condition of the control parameter of the network configuration type converter, and solving the optimal parameter configuration through an optimization algorithm based on the optimal configuration model. The application analyzes and couples the control parameter of the network configuration type converter, establishes comprehensive parameter constraint conditions, ensures that the converter can provide stable frequency response and frequency modulation performance while meeting the synchronous support capability of the power grid, and is helpful to improving the overall stability and response capability of the power grid.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power system planning, in particular to a method for optimizing configuration of multi-point grid-connected converters to meet synchronous support capability requirements. BACKGROUND

[0002] With large-scale development of intermittent new energy generation represented by wind power and photovoltaic power, grid-connected converters are increasingly widely used in modern power systems. However, capacity configuration and modification of the converters are very important. On the one hand, the synchronous support capability requirements of the power system need to be met; on the other hand, the economic problem of converter modification cost needs to be considered on the premise of meeting the system performance requirements.

[0003] Currently, the research on multi-point grid-connected converters mainly focuses on control, and there is little research on optimization configuration. The traditional configuration is mainly based on experience and simple calculation, which lacks systematicness and easily leads to unreasonable configuration, affecting the dynamic performance of the system and being poor in economy.

[0004] In order to reasonably optimize the configuration of the grid-connected unit, on the basis of considering the system frequency support capability requirements, the equality and inequality constraint conditions for the control parameters are established; on the basis of considering the converter modification cost, the objective function with the minimum modification cost as the optimization objective is established; and the optimization configuration model of the multi-point grid-connected control unit of the new energy station to meet the synchronous support capability requirements of the power grid is established.

[0005] Currently, no effective solution has been proposed for the problems in the related art. SUMMARY

[0006] In view of the deficiencies of the prior art, the present application proposes a method for optimizing configuration of multi-point grid-connected converters to meet synchronous support capability requirements, which solves the problem that the research on the multi-point grid-connected converters in the prior art mainly focuses on control, and there is little research on optimization configuration, the traditional configuration is mainly based on experience and simple calculation, which lacks systematicness and easily leads to unreasonable configuration, affecting the dynamic performance of the system and being poor in economy.

[0007] To achieve the above object, the present application is implemented by the following technical solutions:

[0008] The method for optimizing configuration of multi-point grid-connected converters to meet synchronous support capability requirements comprises the following steps:

[0009] S1, a multi-point grid-connected unit control architecture is built and an active-frequency droop formula is established to determine the fast frequency response capability and frequency modulation performance requirements of the grid-connected converter;

[0010] S2. Control parameters of the coupled grid-type converter, establish an optimized configuration model that meets the requirements of synchronous support capability, and construct an objective function based on minimizing the transformation cost of the grid-type converter;

[0011] S3. Based on the performance requirements of new energy power plants, establish constraints on the control parameters of grid-connected converters, and solve for the optimal parameter configuration through optimization algorithms based on the optimization configuration model.

[0012] Furthermore, the following steps are taken to construct a multi-point grid unit control architecture and establish an active power-frequency droop formula to determine the fast frequency response capability and frequency regulation performance requirements of the grid converter:

[0013] S11. Obtain the control architecture of a multi-point grid-connected unit, including new energy power generation unit, energy storage unit, grid-type converter, load and grid construction;

[0014] S12. Analyze the virtual synchronous generator of the grid-type converter and establish the active power-frequency droop formula for new energy power plants.

[0015] S13. Set the fast frequency response capability of the grid converter according to the frequency regulation performance requirements when the grid frequency is disturbed.

[0016] Among them, the fast frequency response capability includes the primary frequency regulation coefficient, response time, and frequency regulation deviation of the grid converter.

[0017] Furthermore, the virtual synchronous generator of the grid-type converter is analyzed, and the active power-frequency droop formula of the new energy power plant is established, including the following steps:

[0018] S121. Establish the active power-frequency droop formula for virtual synchronous generators participating in primary frequency regulation of the power grid;

[0019] S122. By establishing a signal model of a virtual synchronous generator, the influence of the virtual moment of inertia and virtual damping coefficient of the virtual synchronous generator on the overshoot and settling time of the power system is analyzed.

[0020] Furthermore, the formula for the droop of active power to frequency in new energy power plants is established as follows:

[0021] Po=(Kpf+D·ω)·Δω+Pref;

[0022] In the formula, P o This represents the theoretical output active power of a grid-type converter.

[0023] K pf This refers to the droop control parameters for grid-type converters.

[0024] Δω represents the difference between the rated angular frequency and the actual angular frequency;

[0025] D represents the virtual damping coefficient;

[0026] P ref This is expressed as the active power reference value for a grid-type converter;

[0027] ω represents the output angular frequency.

[0028] Furthermore, by establishing a signal model of a virtual synchronous generator, the influence of the virtual moment of inertia and virtual damping coefficient of the virtual synchronous generator on the power system overshoot and settling time is analyzed, including the following steps:

[0029] S1221. Based on the operating characteristics of the virtual synchronous generator, establish the dynamic equations of the virtual synchronous generator;

[0030] S1222. Based on the signal model, establish the active power signal model transfer function of the virtual synchronous generator;

[0031] S1223. Based on the transfer function, determine the natural oscillation angular frequency and damping coefficient of the virtual synchronous generator to evaluate the inertia and damping characteristics of the power system.

[0032] S1224. If the power system is in an underdamped state, based on the preset error band, confirm the influence of virtual moment of inertia and virtual damping coefficient on the power system overshoot and settling time.

[0033] Furthermore, for the control parameters of the coupled grid-type converter, an optimized configuration model is established to meet the requirements of synchronous support capability, and an objective function based on minimizing the retrofit cost of the grid-type converter is constructed, including the following steps:

[0034] S21. Couple the active power, droop control parameters, virtual damping coefficient and virtual moment of inertia of multiple grid-type converters respectively to obtain the total active power, total droop control parameters, total virtual damping coefficient and total virtual moment of inertia of all grid-type converters in the power system.

[0035] S22. Based on the total active power, total droop control parameters, total virtual damping coefficient and total virtual moment of inertia of the grid-type converter, establish an optimal configuration model that meets the requirements of synchronous support capability.

[0036] S23. Based on the optimization configuration model, construct an objective function with the goal of minimizing the transformation cost of the grid-type converter.

[0037] Furthermore, the formulas for coupling the active power, droop control parameters, virtual damping coefficients, and virtual moments of inertia of multiple grid-type converters are as follows:

[0038]

[0039] In the formula, P n It represents the total active power after coupling of all grid-type converters;

[0040] K pf This represents the total droop control parameter after coupling of all grid-type converters;

[0041] D represents the total virtual damping coefficient after coupling of all grid-type converters;

[0042] J represents the total virtual moment of inertia after coupling of all grid-type converters;

[0043] n represents the total number of grid-type converters;

[0044] i represents the i-th grid-type converter.

[0045] Furthermore, the formula for constructing the objective function is as follows:

[0046] min C=(a·P n +b·K pf +c·D·J);

[0047] In the formula, C represents the retrofit cost of the grid-type converter;

[0048] P n It represents the total active power after coupling of all grid-type converters;

[0049] K pf This represents the total droop control parameter after coupling of all grid-type converters;

[0050] D represents the total virtual damping coefficient after coupling of all grid-type converters;

[0051] J represents the total virtual moment of inertia after coupling of all grid-type converters;

[0052] n represents the total number of grid-type converters;

[0053] 'a' represents the cost coefficient for retrofitting the active power of the grid-type converter;

[0054] b represents the cost coefficient for modifying the droop control parameters of the grid-type converter;

[0055] c represents the cost coefficient for modifying the damping inertia of the grid-type converter.

[0056] Furthermore, based on the performance requirements of new energy power plants, constraints are established for the control parameters of grid-connected converters. Based on the optimization configuration model, the optimal parameter configuration is solved using an optimization algorithm, including the following steps:

[0057] S31. Multiple initial sets of modification capacity, droop control parameters, virtual damping coefficients and virtual moments of inertia are randomly generated through optimization algorithms.

[0058] S32. Substitute the modification capacity, droop control parameters, virtual damping coefficient, and virtual moment of inertia into the objective function to calculate the fitness value;

[0059] S33. Find the solution that satisfies all constraints and has the minimum fitness. Through multiple iterations, obtain the optimal configuration of the network control unit parameters that satisfies the set objectives and constraints in the given search space.

[0060] Furthermore, the constraints on the control parameters of the grid-type converter include inequality constraints and equality constraints.

[0061] The formula for the inequality constraint is as follows:

[0062]

[0063] D min ≤D≤D max ;

[0064] J min ≤J≤J max ;

[0065] In the formula, ω0 represents the rated angular frequency of the power system;

[0066] Δω represents the difference between the rated angular frequency and the actual angular frequency;

[0067] ΔP e This represents the primary frequency regulation active power output demand of a grid-type converter.

[0068] D max D min These represent the upper and lower limits of the virtual damping coefficient, respectively.

[0069] J max J min These represent the upper and lower limits of the virtual moment of inertia, respectively.

[0070] The formula for the equality constraint is:

[0071]

[0072] In the formula, P1, P2 and P i These represent the active power of the first grid-type converter, the active power of the second grid-type converter, and the active power of the i-th grid-type converter, respectively.

[0073] k1, k2 and k iThese represent the droop control parameters of the first grid-type converter, the second grid-type converter, and the i-th grid-type converter, respectively.

[0074] D1, D2 and D i These represent the virtual damping coefficients of the first grid-type converter, the second grid-type converter, and the i-th grid-type converter, respectively.

[0075] J1, J2 and J i These represent the virtual rotational inertia of the first grid-type converter, the virtual rotational inertia of the second grid-type converter, and the virtual rotational inertia of the i-th grid-type converter, respectively.

[0076] The beneficial effects of this invention are as follows:

[0077] 1. This invention establishes a control architecture for multi-point grid-connected units and, combined with the active power-frequency droop control strategy of new energy power plants, clarifies the system's requirements for fast frequency response and frequency regulation performance. By analyzing and coupling the control parameters of the grid-connected converter, comprehensive parameter constraints are established. These constraints ensure that the converter, while meeting the grid's synchronization support capabilities, can provide stable frequency response and frequency regulation performance, thus contributing to improving the overall stability and responsiveness of the power grid.

[0078] 2. This invention constructs an optimized configuration model that satisfies the grid's synchronous support capability. The objective function focuses on minimizing the converter modification cost, comprehensively considering the active power, droop control parameters, virtual damping coefficient, and virtual rotational inertia modification cost of the grid-connected converter. This not only meets the requirements of system stability and performance but also significantly reduces the converter modification cost, achieving dual optimization of technology and economy. Applying optimization algorithms to solve the model can quickly find the optimal control parameter configuration, enabling multiple grid-connected converters to have good synchronous support and load distribution capabilities when operating in parallel. In practical applications, the optimal parameter configuration scheme ensures the rapid response capability of new energy power plants when the grid frequency fluctuates, allowing the new energy power generation system to effectively participate in grid frequency regulation and improving system stability and reliability.

[0079] 3. The present invention enables the optimized converter to operate effectively within the frequency response dead zone of new energy power plants (such as wind and photovoltaic power plants), thereby enhancing the dynamic performance of the system. By meeting the adjustment requirements of the grid frequency response limit, the present invention improves the frequency regulation effect of new energy power plants in the grid, enhances the grid adaptability and support capability of new energy, and provides a guarantee for the large-scale grid connection of new energy. Attached Figure Description

[0080] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0081] Figure 1 This is a flowchart of a method for optimizing the configuration of a multi-point grid-type converter to meet the requirements of synchronous support capability according to an embodiment of the present invention;

[0082] Figure 2 This is a control architecture diagram of the network control unit in the multi-point network converter optimization configuration method that meets the synchronous support capability requirements according to an embodiment of the present invention;

[0083] Figure 3 This is a schematic diagram of the active-frequency droop characteristics of a photovoltaic power station with fast frequency response according to an embodiment of the present invention;

[0084] Figure 4 This is a schematic diagram of the active-frequency droop characteristics of a wind farm with fast frequency response according to an embodiment of the present invention.

[0085] Figure 5 This is a block diagram of the active-frequency control of a virtual synchronous generator according to an embodiment of the present invention. Detailed Implementation

[0086] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0087] In the description of this invention, unless otherwise stated, "a plurality of" means two or more. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0088] According to an embodiment of the present invention, an optimized configuration method for multi-point grid-type converters that meets the requirements for synchronous support capability is provided.

[0089] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments, such as... Figure 1 As shown, the multi-point grid-type converter optimization configuration method according to an embodiment of the present invention, which meets the requirements of synchronous support capability, includes the following steps:

[0090] S1. Build a multi-point grid unit control architecture and establish an active power-frequency droop formula to determine the fast frequency response capability and frequency regulation performance requirements of the grid converter.

[0091] It needs to be explained that, considering new energy power generation units, energy storage units, grid-connected converters, loads, and the power grid, a control architecture for multi-point grid-connected units is built; the control strategy of the grid-connected converter is analyzed through new energy sources, and a droop formula for the active power-frequency ratio of the new energy power plant is established; based on the performance requirements of the new energy power plant in response to grid frequency changes, such as the primary frequency regulation coefficient, response time, adjustment time, and response deviation, when the grid experiences frequency disturbances, the rapid frequency response capability of the grid-connected control unit is determined.

[0092] Specifically, the control strategy refers to Virtual Synchronous Generator (VSG) control.

[0093] S2. Control parameters of the coupled grid-type converter, establish an optimized configuration model that meets the requirements of synchronous support capability, and construct an objective function based on minimizing the transformation cost of the grid-type converter;

[0094] It should be explained that the droop control parameters, virtual damping coefficients, and virtual moments of inertia of multiple grid-type converters are coupled; and an objective function based on minimizing the converter retrofit cost is established while meeting the requirements of the power system's synchronous support capability.

[0095] It should be explained that the synchronous support capability requirement is mainly the primary frequency regulation support capability requirement; if the configured parameters can meet the set constraints, when the power system experiences frequency disturbances, the new energy power stations that have undergone grid transformation can actively adjust their output active power to maintain the frequency stability of the power system.

[0096] S3. Based on the performance requirements of new energy power plants, establish constraints on the control parameters of grid-connected converters, and solve for the optimal parameter configuration through optimization algorithms based on the optimization configuration model.

[0097] It should be explained that, based on the performance requirements of new energy power plants, inequalities and equality constraints are established for the droop control parameters, virtual damping coefficients, and virtual moment of inertia of the grid-type converter; the proposed model is optimized and solved using an optimization algorithm to obtain the optimal configuration of the grid-type control unit parameters.

[0098] It should be clarified that the performance requirements refer to the rapid frequency response requirements of new energy power stations, which specifically include:

[0099] 1) The VSG active frequency modulation start-up time is no more than 100ms;

[0100] 2) The active frequency modulation adjustment time of VSG shall not exceed 1 second;

[0101] 3) The maximum active power regulation of VSG participating in primary frequency regulation should not be less than 10% of the rated power.

[0102] Preferably, the process of building a multi-point grid unit control architecture and establishing an active power-frequency droop formula to determine the fast frequency response capability and frequency regulation performance requirements of the grid converter includes the following steps:

[0103] S11. Obtain the control architecture of a multi-point grid-connected unit, including new energy power generation unit, energy storage unit, grid-type converter, load and grid construction;

[0104] It needs to be explained that the network control unit control architecture is as follows: Figure 2 As shown, the system consists of a new energy generation unit, an energy storage unit, a converter, loads, and a power grid. By equipping the grid-connected side of the new energy inverter with a certain capacity of energy storage modules, the entire power system possesses primary frequency regulation control capabilities. In the event of frequency fluctuations on the grid or load side, as well as fluctuations in new energy output, the energy storage regulation module compensates for the power system's power demand. New energy power plants, especially wind and solar power plants, require grid-connected control units to provide grid synchronization support capabilities, ensuring dynamic response during grid frequency fluctuations and meeting rapid frequency response requirements.

[0105] It should be explained that the energy storage module refers to battery energy storage. After configuring a certain capacity of energy storage on the DC side, when the grid connection point frequency crosses the frequency regulation dead zone, the active power target value is calculated based on the active power-frequency droop characteristic of the VSG. Control commands are then distributed and issued to the DC / DC converter connected to the energy storage system according to the active power control strategy. By adjusting the duty cycle, the voltage and current of the energy storage battery are changed, thereby changing the output power and realizing the primary frequency regulation function.

[0106] It needs to be explained that, for example Figures 3-4 As shown, 49.94Hz–50.06Hz is the non-active region for the fast frequency response of photovoltaic power plants, and 49.8Hz and 50.2Hz are the fast frequency response limits for photovoltaic power plants; 49.9Hz–50.1Hz is the non-active region for the fast frequency response of wind farms, and 49.8Hz and 50.2Hz are the fast frequency response limits for wind farms. In the power system, Pn refers to the rated active power after coupling of all grid-connected converters, and P(MW) refers to the actual output active power.

[0107] S12. Analyze the virtual synchronous generator of the grid-type converter and establish the active power-frequency droop formula for new energy power plants.

[0108] S13. Set the fast frequency response capability of the grid converter according to the frequency regulation performance requirements when the grid frequency is disturbed.

[0109] Among them, the fast frequency response capability includes the primary frequency regulation coefficient, response time, and frequency regulation deviation of the grid converter.

[0110] Preferably, the analysis of the virtual synchronous generator of the grid-type converter and the establishment of the active power-frequency droop formula for the new energy power station include the following steps:

[0111] S121. Establish the active power-frequency droop formula for virtual synchronous generators participating in primary frequency regulation of the power grid;

[0112] It should be explained that the active power-frequency droop formula for establishing a virtual synchronous generator to participate in the primary frequency regulation of the power grid is as follows:

[0113] Pm = Kpf·Δω + Pref;

[0114] In the formula, P m This represents the theoretical output active power of a grid-type converter.

[0115] K pf This refers to the droop control parameters for grid-type converters.

[0116] Δω represents the difference between the rated angular frequency and the actual angular frequency;

[0117] P ref This is expressed as the active power reference value for a grid-type converter.

[0118] S122. By establishing a signal model of a virtual synchronous generator, the influence of the virtual moment of inertia and virtual damping coefficient of the virtual synchronous generator on the overshoot and settling time of the power system is analyzed.

[0119] Preferably, the active power-frequency droop formula for a new energy power plant is established as follows:

[0120] Po=(Kpf+D·ω)·Δω+Pref;

[0121] In the formula, P o This is expressed as the theoretical output active power of a new energy power plant;

[0122] K pf This refers to the droop control parameters for grid-type converters.

[0123] Δω represents the difference between the rated angular frequency and the actual angular frequency;

[0124] D represents the virtual damping coefficient;

[0125] P ref This is expressed as the active power reference value for a grid-type converter;

[0126] ω represents the output angular frequency.

[0127] Preferably, the analysis of the impact of the virtual moment of inertia and virtual damping coefficient of the virtual synchronous generator on the power system overshoot and settling time by establishing a signal model of the virtual synchronous generator includes the following steps:

[0128] S1221. Based on the operating characteristics of the virtual synchronous generator, establish the dynamic equations of the virtual synchronous generator;

[0129] It should be explained that, since the grid-type converter uses VSG control, the synchronous support capability of the grid-type converter is analyzed through the rotor motion equations of the VSG, reflecting the inertia and damping characteristics of the VSG. The rotor motion equations of the VSG are as follows:

[0130]

[0131] In the formula, J represents the virtual moment of inertia;

[0132] D represents the virtual damping coefficient;

[0133] ω0 represents the rated angular frequency;

[0134] ω represents the output angular frequency;

[0135] P m This represents the theoretical output active power of a grid-type converter.

[0136] P e This represents the output active power of a grid-type converter.

[0137] S1222. Based on the signal model, establish the active power signal model transfer function of the virtual synchronous generator;

[0138] It should be explained that the formula for establishing the transfer function is as follows:

[0139]

[0140] In the formula, J represents the virtual moment of inertia;

[0141] D represents the virtual damping coefficient;

[0142] E represents the output voltage of the VSG;

[0143] U represents the grid voltage;

[0144] Z represents the line impedance;

[0145] ω0 represents the rated angular frequency;

[0146] K pf This refers to the droop control parameters for grid-type converters.

[0147] G(s) is represented as the transfer function.

[0148] S1223. Based on the transfer function, determine the natural oscillation angular frequency and damping coefficient of the virtual synchronous generator to evaluate the inertia and damping characteristics of the power system.

[0149] It should be explained that the formulas for obtaining the natural oscillation angular frequency and damping coefficient of the corresponding second-order model from the transfer function are as follows:

[0150]

[0151] In the formula, ω n Expressed as the natural oscillation angular frequency;

[0152] ξ represents the damping coefficient;

[0153] J represents the virtual moment of inertia;

[0154] D represents the virtual damping coefficient;

[0155] E represents the output voltage of the VSG;

[0156] U represents the grid voltage;

[0157] Z represents the line impedance;

[0158] ω0 represents the rated angular frequency.

[0159] S1224. If the power system is in an underdamped state, based on the preset error band, confirm the influence of virtual moment of inertia and virtual damping coefficient on the power system overshoot and settling time.

[0160] It should be explained that, assuming the system is in an underdamped state, and an error band of Δ = 2%, the system overshoot and settling time are as follows:

[0161]

[0162] In the formula, σ% represents the overshoot;

[0163] t s This is indicated as adjustment time;

[0164] J represents the virtual moment of inertia;

[0165] K pf This refers to the droop control parameters for grid-type converters.

[0166] ω0 represents the rated angular frequency;

[0167] e represents the natural constant, which has a value of approximately 2.718.

[0168] Preferably, the control parameters of the coupled grid-type converter are used to establish an optimized configuration model that meets the requirements of synchronous support capability, and an objective function based on minimizing the retrofit cost of the grid-type converter is constructed, including the following steps:

[0169] S21. Couple the active power, droop control parameters, virtual damping coefficient and virtual moment of inertia of multiple grid-type converters respectively to obtain the total active power, total droop control parameters, total virtual damping coefficient and total virtual moment of inertia of all grid-type converters in the power system.

[0170] S22. Based on the total active power, total droop control parameters, total virtual damping coefficient and total virtual moment of inertia of the grid-type converter, establish an optimal configuration model that meets the requirements of synchronous support capability.

[0171] S23. Based on the optimization configuration model, construct an objective function with the goal of minimizing the transformation cost of the grid-type converter.

[0172] Preferably, the formula for coupling the active power, droop control parameters, virtual damping coefficient, and virtual moment of inertia of multiple grid-type converters is as follows:

[0173]

[0174] In the formula, P n It represents the total active power after coupling of all grid-type converters;

[0175] K pf This represents the total droop control parameter after coupling of all grid-type converters;

[0176] D represents the total virtual damping coefficient after coupling of all grid-type converters;

[0177] J represents the total virtual moment of inertia after coupling of all grid-type converters;

[0178] n represents the total number of grid-type converters;

[0179] i represents the i-th grid-type converter.

[0180] Preferably, the formula for constructing the objective function is:

[0181] min C=(a·P n +b·K pf +c·D·J);

[0182] In the formula, C represents the retrofit cost of the grid-type converter;

[0183] P n It represents the total active power after coupling of all grid-type converters;

[0184] K pf This represents the total droop control parameter after coupling of all grid-type converters;

[0185] D represents the total virtual damping coefficient after coupling of all grid-type converters;

[0186] J represents the total virtual moment of inertia after coupling of all grid-type converters;

[0187] n represents the total number of grid-type converters;

[0188] 'a' represents the cost coefficient for retrofitting the active power of the grid-type converter;

[0189] b represents the cost coefficient for modifying the droop control parameters of the grid-type converter;

[0190] c represents the cost coefficient for modifying the damping inertia of the grid-type converter.

[0191] Specifically, damping inertia refers to the virtual damping coefficient and the virtual moment of inertia.

[0192] Preferably, based on the performance requirements of the new energy power plant, constraints are established on the control parameters of the grid-connected converter. Based on the optimization configuration model, the optimal parameter configuration is solved using an optimization algorithm, including the following steps:

[0193] S31. Multiple initial sets of modification capacity (i.e., active power), droop control parameters, virtual damping coefficients and virtual moments of inertia are randomly generated through optimization algorithms.

[0194] S32. Substitute the modification capacity, droop control parameters, virtual damping coefficient, and virtual moment of inertia into the objective function to calculate the fitness value;

[0195] S33. Find the solution that satisfies all constraints and has the minimum fitness. Through multiple iterations, obtain the optimal configuration of the network control unit parameters that satisfies the set objectives and constraints in the given search space.

[0196] Preferably, the constraints on the control parameters of the grid-type converter include inequality constraints and equality constraints;

[0197] The formula for the inequality constraint is as follows:

[0198]

[0199] D min ≤D≤D max ;

[0200] J min ≤J≤J max ;

[0201] In the formula, ω0 represents the rated angular frequency of the power system;

[0202] Δω represents the difference between the rated angular frequency and the actual angular frequency;

[0203] ΔP e This represents the primary frequency regulation active power output demand of a grid-type converter.

[0204] D max D min These represent the upper and lower limits of the virtual damping coefficient, respectively.

[0205] J max J min These represent the upper and lower limits of the virtual moment of inertia, respectively.

[0206] The formula for the equality constraint is:

[0207]

[0208] In the formula, P1, P2 and P i These represent the active power of the first grid-type converter, the active power of the second grid-type converter, and the active power of the i-th grid-type converter, respectively.

[0209] k1, k2 and k i These represent the droop control parameters of the first grid-type converter, the second grid-type converter, and the i-th grid-type converter, respectively.

[0210] D1, D2 and D i These represent the virtual damping coefficients of the first grid-type converter, the second grid-type converter, and the i-th grid-type converter, respectively.

[0211] J1, J2 and J i These represent the virtual rotational inertia of the first grid-type converter, the virtual rotational inertia of the second grid-type converter, and the virtual rotational inertia of the i-th grid-type converter, respectively.

[0212] It needs to be explained that when grid-connected converters of different capacities are operated in parallel, in order to achieve reasonable power distribution among the converters, it is necessary to analyze the parameter setting principles for multiple converters of different capacities operating in parallel. Taking two converters operating in parallel as an example, such as... Figure 5 As shown, the frequency deviation is 0 in steady state. Therefore, the configuration principles for J1, J2, D1, and D2 in the system are as follows:

[0213]

[0214] In the formula, J1 and J2 represent the virtual rotational inertia of the first grid-type converter and the virtual rotational inertia of the second grid-type converter, respectively.

[0215] D1 and D2 represent the virtual damping coefficients of the first grid-type converter and the second grid-type converter, respectively.

[0216] It should be noted that m is merely a ratio, indicating that the ratio in the current formula is the same as that in the formula below.

[0217] When the capacities of the two converters are set proportionally, their output active power should obviously be distributed according to the same proportional relationship. On the other hand, based on the active power-frequency expression, combining the active power ratio with the active power droop formula yields:

[0218]

[0219] In the formula, P1 and P2 represent the active power of the first grid-type converter and the active power of the second grid-type converter, respectively.

[0220] k1 and k2 represent the droop control parameters of the first grid-type converter and the second grid-type converter, respectively.

[0221] Δω represents the difference between the rated angular frequency and the actual angular frequency;

[0222] P ref1 P ref2 These are represented as the active power reference values ​​for the first grid-type converter and the second grid-type converter, respectively.

[0223] Since the angular frequencies of all converters are the same, the configuration principles for the droop control parameters k1 and k2 in the system can be obtained as follows:

[0224]

[0225] In the formula, k1 and k2 represent the droop control parameters of the first grid-type converter and the second grid-type converter, respectively.

[0226] Based on the above analysis, in order to achieve reasonable power distribution among the converters and obtain better operating characteristics, equality constraints for the network control parameters are established.

[0227] In summary, by utilizing the above-mentioned technical solution of this invention, the present invention constructs an optimized configuration model that satisfies the grid's synchronous support capability. The objective function focuses on minimizing the converter's retrofit cost, comprehensively considering the active power, droop control parameters, virtual damping coefficient, and virtual moment of inertia retrofit cost of the grid-connected converter. This not only meets the requirements of system stability and performance but also significantly reduces the converter's retrofit cost, achieving dual optimization of technology and economy. Applying optimization algorithms to solve the model allows for the rapid finding of the optimal control parameter configuration, enabling multiple grid-connected converters to have good synchronous support and load distribution capabilities when operating in parallel. In practical applications, the optimal parameter configuration ensures the rapid response capability of new energy power plants during grid frequency fluctuations, allowing new energy power generation systems to effectively participate in grid frequency regulation and improving system stability and reliability. The optimized converter configuration allows the system to operate effectively within the frequency response dead zone of new energy power plants (such as wind and photovoltaic power plants), enhancing the system's dynamic performance. By meeting the grid frequency response limit adjustment requirements, this invention improves the frequency regulation effect of new energy power plants in the grid, enhances the grid adaptability and support capability of new energy, and provides a guarantee for large-scale new energy grid integration.

[0228] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for optimizing the configuration of multi-point grid-type converters to meet synchronous support capability requirements, characterized in that, The method for optimizing the configuration of multi-point network converters includes the following steps: S1. Build a multi-point grid unit control architecture and establish an active power-frequency droop formula to determine the fast frequency response capability and frequency regulation performance requirements of the grid converter. S2. Control parameters of the coupled grid-type converter, establish an optimized configuration model that meets the requirements of synchronous support capability, and construct an objective function based on minimizing the transformation cost of the grid-type converter; S3. Based on the performance requirements of new energy power plants, establish constraints on the control parameters of grid-connected converters, and solve for the optimal parameter configuration through optimization algorithms based on the optimization configuration model. The control parameters of the coupled grid-type converter are configured using an optimized configuration model that meets the requirements of synchronous support capability. The objective function for minimizing the retrofit cost of the grid-type converter is constructed, including the following steps: S21. Couple the active power, droop control parameters, virtual damping coefficient and virtual moment of inertia of multiple grid-type converters respectively to obtain the total active power, total droop control parameters, total virtual damping coefficient and total virtual moment of inertia of all grid-type converters in the power system. S22. Based on the total active power, total droop control parameters, total virtual damping coefficient and total virtual moment of inertia of the grid-type converter, establish an optimal configuration model that meets the requirements of synchronous support capability. S23. Based on the optimization configuration model, construct an objective function with the goal of minimizing the retrofit cost of the grid-type converter. The process of establishing constraints on the control parameters of the grid-connected converter based on the performance requirements of the new energy power plant, and solving for the optimal parameter configuration through an optimization algorithm based on the optimization configuration model, includes the following steps: S31. Multiple initial sets of modification capacity, droop control parameters, virtual damping coefficients and virtual moments of inertia are randomly generated through optimization algorithms. S32. Substitute the modification capacity, droop control parameters, virtual damping coefficient, and virtual moment of inertia into the objective function to calculate the fitness value; S33. Find the solution that satisfies all constraints and has the minimum fitness. Through multiple iterations, obtain the optimal configuration of the network control unit parameters that satisfies the set objectives and constraints in the given search space.

2. The method for optimizing the configuration of multi-point grid-type converters that meets the requirements for synchronous support capability as described in claim 1, characterized in that, The process of constructing a multi-point grid unit control architecture and establishing an active power-frequency droop formula to determine the fast frequency response capability and frequency regulation performance requirements of the grid converter includes the following steps: S11. Obtain the control architecture of a multi-point grid-connected unit, including new energy power generation unit, energy storage unit, grid-type converter, load and grid construction; S12. Analyze the virtual synchronous generator of the grid-type converter and establish the active power-frequency droop formula for new energy power plants. S13. Set the fast frequency response capability of the grid converter according to the frequency regulation performance requirements when the grid frequency is disturbed. Among them, the fast frequency response capability includes the primary frequency regulation coefficient, response time, and frequency regulation deviation of the grid converter.

3. The method for optimizing the configuration of multi-point grid-type converters that meets the requirements for synchronous support capability according to claim 2, characterized in that, The analysis of the virtual synchronous generator of the grid-type converter and the establishment of the active power-frequency droop formula for new energy power plants include the following steps: S121. Establish the active power-frequency droop formula for virtual synchronous generators participating in primary frequency regulation of the power grid; S122. By establishing a signal model of a virtual synchronous generator, the influence of the virtual moment of inertia and virtual damping coefficient of the virtual synchronous generator on the overshoot and settling time of the power system is analyzed.

4. The method for optimizing the configuration of multi-point grid-type converters that meets the requirements for synchronous support capability as described in claim 3, characterized in that, The formula for establishing the active power-frequency droop of a new energy power station is as follows: ； In the formula, P o This represents the theoretical output active power of a grid-type converter. K pf This refers to the droop control parameters for grid-type converters. Δω represents the difference between the rated angular frequency and the actual angular frequency; D represents the virtual damping coefficient; P ref This is expressed as the active power reference value for a grid-type converter; ω represents the output angular frequency.

5. The method for optimizing the configuration of multi-point grid-type converters that meets the requirements for synchronous support capability according to claim 4, characterized in that, The process of establishing a signal model of a virtual synchronous generator and analyzing the impact of the virtual moment of inertia and virtual damping coefficient of the virtual synchronous generator on the overshoot and settling time of the power system includes the following steps: S1221. Based on the operating characteristics of the virtual synchronous generator, establish the dynamic equations of the virtual synchronous generator; S1222. Based on the signal model, establish the active power signal model transfer function of the virtual synchronous generator; S1223. Based on the transfer function, determine the natural oscillation angular frequency and damping coefficient of the virtual synchronous generator to evaluate the inertia and damping characteristics of the power system. S1224. If the power system is in an underdamped state, based on the preset error band, confirm the influence of virtual moment of inertia and virtual damping coefficient on the power system overshoot and settling time.

6. The method for optimizing the configuration of multi-point grid-type converters that meets the requirements for synchronous support capability as described in claim 1, characterized in that, The formula for coupling the active power, droop control parameters, virtual damping coefficient, and virtual moment of inertia of multiple grid-type converters is as follows: ； ； ； ； In the formula, P n It represents the total active power after coupling of all grid-type converters; K pf This represents the total droop control parameter after coupling of all grid-type converters; D represents the total virtual damping coefficient after coupling of all grid-type converters; J represents the total virtual moment of inertia after coupling of all grid-type converters; n represents the total number of grid-type converters; i represents the i-th grid-type converter.

7. The method for optimizing the configuration of multi-point grid-type converters that meets the requirements for synchronous support capability as described in claim 6, characterized in that, The formula for constructing the objective function is as follows: ； In the formula, C represents the retrofit cost of the grid-type converter; P n It represents the total active power after coupling of all grid-type converters; K pf This represents the total droop control parameter after coupling of all grid-type converters; D represents the total virtual damping coefficient after coupling of all grid-type converters; J represents the total virtual moment of inertia after coupling of all grid-type converters; n represents the total number of grid-type converters; 'a' represents the cost coefficient for retrofitting the active power of the grid-type converter; b represents the cost coefficient for modifying the droop control parameters of the grid-type converter; c represents the cost coefficient for modifying the damping inertia of the grid-type converter.

8. The method for optimizing the configuration of multi-point grid-type converters that meets the requirements for synchronous support capability according to claim 1, characterized in that, The constraints on the control parameters of the grid-type converter include inequality constraints and equality constraints. The formula for the inequality constraint is as follows: ； ； ； In the formula, ω0 represents the rated angular frequency of the power system; Δω represents the difference between the rated angular frequency and the actual angular frequency; ΔP e This represents the primary frequency regulation active power output demand of a grid-type converter. D max D min These represent the upper and lower limits of the virtual damping coefficient, respectively. J max J min These represent the upper and lower limits of the virtual moment of inertia, respectively. The formula for the equality constraint is: ； ； ； In the formula, P1, P2 and P i These represent the active power of the first grid-type converter, the active power of the second grid-type converter, and the active power of the i-th grid-type converter, respectively. k1, k2 and k i These represent the droop control parameters of the first grid-type converter, the second grid-type converter, and the i-th grid-type converter, respectively. D1, D2 and D i These represent the virtual damping coefficients of the first grid-type converter, the second grid-type converter, and the i-th grid-type converter, respectively. J1, J2 and J i These represent the virtual rotational inertia of the first grid-type converter, the virtual rotational inertia of the second grid-type converter, and the virtual rotational inertia of the i-th grid-type converter, respectively.

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