A method, device, equipment and medium for optimizing configuration of a multi-constellation converter

Abstract

The present application relates to the technical field of wind power generation, and discloses a method, device, equipment and medium for optimizing configuration of multi-network converter. The method comprises: constructing a mathematical model of an interconnected system composed of multiple network-type converters according to power coupling effects between the multiple network-type converters; constructing a network model of the interconnected system for describing energy interaction processes of the multiple network-type converters when coupled according to the mathematical model of the interconnected system; obtaining an interaction energy coefficient for reflecting whether stored energy of each network-type converter in the interconnected system is dissipated or accumulated according to dissipated energy and interaction energy of each network-type converter; and determining an optimal configuration of the multiple network-type converters for different configuration schemes of the multiple network-type converters by obtaining the interaction energy coefficients corresponding to the different configuration schemes, with the network-type converters being in different installation positions and / or the network-type converters adopting different control parameters in the interconnected system.

Description

Technical Field

[0001] This invention relates to the field of wind power generation technology, and in particular to an optimized configuration method, apparatus, equipment and medium for multi-grid converters. Background Technology

[0002] The new power system exhibits a "dual high" development trend of high proportion of new energy sources and high proportion of power electronics, while the proportion of synchronous generators is gradually declining, resulting in a weakly damped and weakly supported grid with low anti-interference capability. To ensure the stable operation of the future new power system, it is necessary to introduce grid-type converters with voltage source characteristics to support the voltage and inertia of the grid and improve the system's anti-interference capability.

[0003] However, when large-scale grid-connected converters are connected to the grid, it is equivalent to multiple voltage sources operating in parallel. There are mutual coupling effects between multiple grid control commands, which can easily lead to multi-mode oscillation instability problems under low-impedance grid conditions. Summary of the Invention

[0004] The purpose of this invention is to provide an optimized configuration method, apparatus, equipment, and medium for multi-grid converters, which can solve the multi-mode oscillation instability problem caused by large-scale grid-type converters being connected to the power grid under low-impedance grid conditions.

[0005] To address the aforementioned technical problems, embodiments of the present invention provide an optimized configuration method for multi-network converters, comprising the following steps:

[0006] Based on the power coupling effect between multiple grid-type converters in an interconnected system, a mathematical model of the interconnected system is constructed.

[0007] Based on the mathematical model of the interconnected system, a network model of the interconnected system is constructed to describe the energy interaction process of multiple grid-type converters during power coupling; wherein, the network model of the interconnected system is used to reflect the stored energy and dissipated energy generated by each grid-type converter independently, as well as the interactive energy generated during power coupling.

[0008] Based on the dissipated energy and interactive energy of each grid converter, obtain the interactive energy coefficient to reflect whether the stored energy of each grid converter in the interconnected system is dissipated or accumulated.

[0009] Given that the grid-type converters in the interconnected system are located in different installation positions and / or the grid-type converters use different control parameters, different configuration schemes for multiple grid-type converters in the interconnected system are given. By obtaining the interaction energy coefficients of the interconnected system corresponding to different configuration schemes, the optimal configuration of multiple grid-type converters is determined.

[0010] Optionally, the step of constructing a mathematical model of the interconnected system based on the power coupling effect among multiple grid-type converters in the interconnected system includes:

[0011] For each grid-type converter in the interconnected system, based on the active-phase angle outer loop control module and the reactive-voltage outer loop control module of the grid-type converter, the active-phase angle outer loop control model and the reactive-voltage outer loop control model of the grid-type converter are established respectively.

[0012] Based on the grid connection structure of multiple grid-type converters, and according to the active-phase angle outer loop control model and reactive-voltage outer loop control model of the grid-type converters, the active power and reactive power transmitted by each grid-type converter to the common bus, and the active power and reactive power transmitted by the common bus to each grid-type converter are obtained respectively.

[0013] A mathematical model of the interconnected system is constructed based on the active and reactive power transmitted by each of the multiple grid-type converters to the common bus, and the active and reactive power transmitted by the common bus to each of the multiple grid-type converters.

[0014] Optionally, each of the grid-type converters includes an active subsystem and a reactive subsystem. The step of constructing a network model of the interconnected system, based on the mathematical model of the interconnected system, to describe the energy interaction process of multiple grid-type converters during power coupling, includes:

[0015] Based on the mathematical model of the interconnected system, the energy interaction process of the first energy interaction path formed by the active subsystem and reactive subsystem of each grid-type converter, the energy interaction process of the second energy interaction path formed by the active subsystems of different grid-type converters, the energy interaction process of the third energy interaction path formed by the reactive subsystems of different grid-type converters, and the energy interaction process of the fourth energy interaction path formed by the active subsystems and reactive subsystems of different grid-type converters are obtained.

[0016] By combining the energy interaction processes of the first, second, third, and fourth energy interaction paths, a network model of the interconnected system is constructed.

[0017] Optionally, the step of obtaining the interaction energy coefficient, which reflects whether the energy stored in each grid-type converter in the interconnected system is dissipated or accumulated, based on the dissipated energy and interaction energy of each grid-type converter, includes:

[0018] For each grid-type converter in the interconnected system, the aperiodic components of the stored energy, dissipated energy, and interactive energy of the grid-type converter are obtained according to the voltage and phase angle of the grid-type converter.

[0019] Based on the aperiodic components of the dissipated energy and interactive energy of each grid converter, an interactive energy coefficient is obtained to indicate whether the aperiodic component of the stored energy of each grid converter in the interconnected system is dissipated or accumulated.

[0020] Optionally, the step of obtaining the interaction energy coefficient, which reflects whether the aperiodic component of the stored energy of each grid-type converter in the interconnected system is dissipated or accumulated, based on the aperiodic component of the dissipated energy and the interaction energy of each grid-type converter, includes:

[0021] For the first energy interaction path between the active and reactive subsystems of each grid-type converter, the aperiodic components of the stored energy, dissipated energy, and interaction energy of the grid-type converter are extracted based on the voltage and phase angle of the grid-type converter to obtain the interaction energy coefficient of the first energy interaction path.

[0022] For the second energy interaction path between active subsystems of different grid-type converters, the aperiodic components of the stored energy, dissipated energy and interaction energy of the grid-type converter are extracted according to the phase angle of each grid-type converter corresponding to the second energy interaction path, so as to obtain the interaction energy coefficient of the second energy interaction path.

[0023] For the third energy interaction path between the reactive subsystems of different grid-type converters, the aperiodic components of the stored energy, dissipated energy and interaction energy of the grid-type converter are extracted based on the voltage of each grid-type converter corresponding to the third energy interaction path to obtain the interaction energy coefficient of the third energy interaction path.

[0024] For the fourth energy interaction path between the active and reactive subsystems of different grid-type converters, the aperiodic components of the stored energy, dissipated energy, and interaction energy of each grid-type converter corresponding to the fourth energy interaction path are extracted to obtain the interaction energy coefficient of the fourth energy interaction path.

[0025] Optionally, the optimal configuration of the plurality of grid-connected converters includes: the power control response bandwidth of the grid-connected converter that transmits power is greater than the power control response bandwidth of the grid-connected converter that receives power.

[0026] Optionally, the different configuration schemes of multiple grid-type converters in the interconnection system are as follows: the grid-type converters in the interconnection system are located in different installation positions, and / or the grid-type converters adopt different control parameters, and / or the lines between multiple grid-type converters adopt different structural parameters.

[0027] Embodiments of the present invention also provide an optimized configuration device for a multi-grid converter, comprising:

[0028] The first model construction module is used to construct a mathematical model of the interconnected system based on the power coupling effect between multiple grid-type converters in the interconnected system.

[0029] The second model construction module is used to construct a network model of the interconnected system based on the mathematical model of the interconnected system, which describes the energy interaction process of multiple grid-type converters during power coupling; wherein, the network model of the interconnected system is used to reflect the stored energy and dissipated energy generated by each grid-type converter, as well as the interactive energy generated during power coupling.

[0030] The energy analysis module is used to obtain the interaction energy coefficient, which reflects whether the energy stored in each grid converter in the interconnected system is dissipated or accumulated, based on the dissipated energy and interaction energy of each grid converter.

[0031] The optimization configuration module is used to determine the optimal configuration of multiple grid-type converters in an interconnected system, based on different installation locations of grid-type converters in the interconnected system, and / or different control parameters for grid-type converters, and / or different structural parameters for the lines between multiple grid-type converters. By obtaining the interaction energy coefficient of the interconnected system corresponding to different configuration schemes, the module determines the optimal configuration of multiple grid-type converters.

[0032] Embodiments of the present invention also provide a computer device, including: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to execute the above-described optimized configuration method for a multi-network converter.

[0033] Embodiments of the present invention also provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described optimized configuration method for a multi-network converter.

[0034] The optimized configuration method for multi-grid converters provided by this invention has at least the following beneficial effects:

[0035] To address the oscillation and instability problem in an interconnected system composed of multiple grid-type converters, this invention obtains the energy interaction process of these converters during power coupling. This energy interaction process is reflected in the stored energy, dissipated energy, and interacting energy of each grid-type converter. In an interconnected system, the stored energy of the grid-type converters gradually dissipates or accumulates over time. If the stored energy dissipates gradually, the oscillation amplitude of the interconnected system will gradually decrease, eventually reaching a stable state. If the stored energy accumulates continuously, the oscillation amplitude will gradually increase, leading to instability. Therefore, this invention obtains an interacting energy coefficient that reflects whether the stored energy of each grid-type converter in the interconnected system is dissipated or accumulated, based on the dissipated energy and interacting energy of each converter. This interacting energy coefficient can indicate whether the energy interaction process between multiple grid-type converters mitigates or exacerbates the oscillation of the interconnected system.

[0036] At this point, considering different installation locations and / or different control parameters for the grid-type converters in the interconnected system, different configuration schemes for multiple grid-type converters in the interconnected system are presented. By obtaining the interaction energy coefficients of the interconnected system corresponding to different configuration schemes, it can be determined whether the energy interaction process between multiple grid-type converters in different configuration schemes will mitigate or exacerbate the interconnected system oscillations. Based on this, the optimal configuration of multiple grid-type converters can be determined, resulting in a configuration scheme to mitigate interconnected system oscillations. This solves the multi-mode oscillation instability problem caused by large-scale grid-type converters being connected to the grid under low-impedance grid conditions. Attached Figure Description

[0037] One or more embodiments are illustrated by way of example with reference to the accompanying drawings, and these illustrative descriptions do not constitute a limitation on the embodiments.

[0038] Figure 1 This is a flowchart of an optimized configuration method for a multi-network converter according to an embodiment of the present invention;

[0039] Figure 2 This is a schematic diagram of a multi-grid converter interconnection system according to an embodiment of the present invention;

[0040] Figure 3 This is a schematic diagram of simulation curves under different line structure parameters provided according to an embodiment of the present invention;

[0041] Figure 4 This is a schematic diagram of energy change trajectories under different line structure parameters according to an embodiment of the present invention;

[0042] Figure 5This is a schematic diagram of the variation trend of the inter-machine energy interaction coefficient random group power control parameters according to an embodiment of the present invention, wherein (a) is the active subsystem interaction diagram, (b) is the reactive subsystem interaction diagram, and (c) is the active-reactive subsystem interaction diagram;

[0043] Figure 6 This is a schematic diagram of simulation curves under different active power control parameters provided according to an embodiment of the present invention;

[0044] Figure 7 This is a D provided according to an embodiment of the present invention. p1 =5.4,D p2 =3.6 Inter-system interaction energy change trajectory diagram, where (a) is the active subsystem interaction diagram, (b) is the reactive subsystem interaction diagram, and (c) is the active-reactive subsystem interaction diagram;

[0045] Figure 8 This is a D provided according to an embodiment of the present invention. p1 =3.6,D p2 =5.4 Schematic diagram of the energy change trajectory of the inter-system interaction, where (a) is the interaction diagram of the active subsystem, (b) is the interaction diagram of the reactive subsystem, and (c) is the interaction diagram of the active-reactive subsystem. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the various embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details are presented in the embodiments of the present invention to facilitate a better understanding of the invention. However, the technical solutions claimed in the present invention can be implemented even without these technical details and various variations and modifications based on the following embodiments. The division of the following embodiments is for ease of description and should not constitute any limitation on the specific implementation of the present invention. The various embodiments can be combined with and referenced by each other without contradiction.

[0047] One embodiment of the present invention relates to an optimized configuration method for a multi-network converter. The implementation details of the optimized configuration method for the multi-network converter in this embodiment are described in detail below. The following content is only for the convenience of understanding and is not necessary for implementing this solution.

[0048] The specific process of the optimized configuration method for the multi-grid converter in this embodiment is as follows: Figure 1 As shown, it includes:

[0049] Step 101: Based on the power coupling effect between multiple grid-type converters in an interconnected system, construct a mathematical model of the interconnected system.

[0050] Specifically, for each grid-type converter in the interconnected system, based on the active-phase-outer-loop control module and the reactive-voltage-outer-loop control module of the grid-type converter, active-phase-outer-loop control models and reactive-voltage-outer-loop control models are established respectively. Combining the grid-connected structure of multiple grid-type converters, based on the active-phase-outer-loop control models and reactive-voltage-outer-loop control models of the grid-type converters, the active and reactive power transmitted by each grid-type converter to the common bus, and the active and reactive power transmitted by the common bus to each grid-type converter are obtained respectively. Based on the active and reactive power transmitted by each of the multiple grid-type converters to the common bus, and the active and reactive power transmitted by the common bus to the multiple grid-type converters respectively, a mathematical model of the interconnected system is constructed.

[0051] In the specific implementation, firstly, the power outer loop control of a single-structure grid converter is modeled. The grid converter control model based on droop control mainly includes two modules: active power-phase angle outer loop control and reactive power-voltage outer loop control.

[0052] The active-phase outer loop is typically used to simulate the swing equation of a synchronous generator; the second-order differential equation is written as:

[0053]

[0054] In the formula, θ i Let P be the output phase angle of the power loop of the i-th converter. ref and P i J represents the reference value and the actual value of the output active power of the i-th grid-connected converter, respectively. i For virtual inertia, D p,i is the damping coefficient.

[0055] The reactive power loop typically employs droop control, which supports the grid voltage by providing limited reactive power. Its first-order differential equation is:

[0056]

[0057] In the formula, V i and V ref These are the actual and reference values ​​of the PCC point voltage output from the reactive power loop, respectively. Q ref Qi and K represent the reference and actual reactive power values ​​for a grid-type converter, respectively. i D is the voltage integral coefficient; q,i This is the voltage droop factor.

[0058] Considering the grid connection structure of the grid-connected converter, the active and reactive power generated by the i-th grid-connected converter in the above two formulas can be represented by the power flowing from unit i to BusA transmission line, and its expression is:

[0059]

[0060] In the formula, θ iA =θ i -θ A , is the difference between the voltage phase angle at the iPCC point of the unit and the voltage phase angle at BusA; and These are the equivalent conductance and susceptance of the unit's iPCC point from the collecting bus A, respectively.

[0061] Substituting this into the two formulas above, we can obtain the small-signal model for the power control of the i-th grid-type converter as follows:

[0062]

[0063] In the formula,

[0064] A mathematical model of a multi-grid converter interconnection system is established. The multi-grid converters primarily interact through power transfer. Based on the line power transmission equation, the expressions for the active and reactive power transferred from BusA to the i-th generator unit are:

[0065]

[0066] In the formula, P Ai and Q Ai These represent the active and reactive power supplied by BusA to the i-th generator unit, respectively.

[0067] Linearizing it yields:

[0068]

[0069] In the formula,

[0070] Furthermore, by simultaneously solving the power balance equations at the common bus node, the common point bus voltage Δθ can be obtained. A and ΔV A The relationship between the voltage and phase of each converter terminal is as follows:

[0071]

[0072] In the formula,

[0073] Substituting this into the small-signal model of power control for a grid-connected converter, we obtain the small-signal model of the interconnected grid-connected converter system for inter-machine interaction as follows:

[0074]

[0075] In the formula, A i Let F be the state-space matrix of the i-th grid-connected converter. ij Let be the interaction correlation matrix between the j-th converter and the i-th converter, reflecting the coupling process between the j-th and i-th grid-type converters. Δx i and Δx j Let Δx be the state variables of the i-th and j-th converters, respectively. j =[Δθ i, Δω i ,ΔV i ].

[0076] In the formula,

[0077]

[0078]

[0079] As can be seen from this equation, in addition to its own internal voltage-phase coupling, the i-th grid-connected converter also has cross-coupling terms with the state variables of the j-th grid-connected converter, corresponding to the machine-grid interaction and the machine-to-machine interaction, respectively. To further quantify the strength of the machine-to-machine and machine-grid interactions in a multi-grid-connected converter system, this paper constructs an interaction energy model for the grid-connected converter system, explicitly analyzing the impact of the machine-grid and machine-to-machine interactions of the grid-connected converters on the system's oscillation stability.

[0080] Step 102: Based on the mathematical model of the interconnected system, construct a network model of the interconnected system to describe the energy interaction process of multiple grid-type converters during power coupling; wherein, the network model of the interconnected system is used to reflect the stored energy and dissipated energy generated by each grid-type converter independently, as well as the interactive energy generated during power coupling.

[0081] In practical implementation, based on the small-signal model of the interconnected grid-type converter system with inter-machine interaction, the i-th grid-type converter can be divided into an active subsystem and a reactive subsystem, and the dynamic energy function models of the two control subsystems can be established by the first integration method.

[0082] In the active control subsystem Δθ i ,Δω i The state variable equation can be expressed as:

[0083]

[0084] In the formula, x i_2×1 x represents i The first two rows of variables, A i_2×3 and F ij_2×3 They represent A respectively i and F ij The first two lines of parameters.

[0085] Using the first integration method, by cross-multiplying the second-order state variables and integrating left and right, the dynamic energy model expression of the active power control subsystem of the i-th grid-type converter can be obtained as follows:

[0086]

[0087] In the formula, f p1 f p2 f is the active power unit-network interaction coefficient. p3 f p4 These are the interaction coefficients between active power units, all of which are related to the system structural parameters.

[0088]

[0089] The state variable equations of the reactive power control subsystem, obtained by cross-multiplication using the first integration method, yield the following expression for the dynamic energy model of the reactive power control subsystem:

[0090]

[0091] In the formula, f q1 f q2 f is the reactive power grid interaction coefficient. q3 f q4 These are the interaction coefficients between active power units, all of which are related to the system structural parameters.

[0092]

[0093] Combining the dynamic energy model expressions of the active power control subsystem and the reactive power control subsystem, the dynamic energy expression of the i-th grid-type converter can be obtained as follows:

[0094] V i =V i_s -V i_d -V i_t

[0095] In the formula,

[0096] V i_s V represents the total stored energy generated by the i-th unit. i_d V represents the dissipated energy generated by the i-th unit, characterizing the damping effect on the system's oscillation energy. i_tLet be the interaction energy between the internal control links of the i-th unit and between it and the control links of the j-th unit.

[0097] Furthermore, combining the small-signal model of the interconnected grid-type converter system with inter-machine interaction, solving the partial derivative of this equation with respect to time yields:

[0098]

[0099] It can be seen that the partial derivative of the dynamic energy of the i-th grid-type converter with respect to time t is 0, proving that the dynamic energy model of the i-th grid-type converter satisfies the energy conservation requirement. The stored energy and dissipated energy in the system are generated by the units themselves. The interactive energy of the i-th unit is generated by the coupling of the control loop within the unit and the coupling between units, and it is the energy link connecting multiple converters.

[0100] Furthermore, according to V i_t The state variables involved in the various interactive energies determine the interactive objects, and the four types of energy interaction paths existing in the interconnected system can be divided to construct the energy interaction network of the grid-type converter interconnected system.

[0101] Specifically, each grid-type converter includes an active subsystem and a reactive subsystem. Based on the mathematical model of the interconnected system, the energy interaction process of the first energy interaction path formed by the active and reactive subsystems of each grid-type converter, the energy interaction process of the second energy interaction path formed by the active subsystems of different grid-type converters, the energy interaction process of the third energy interaction path formed by the reactive subsystems of different grid-type converters, and the energy interaction process of the fourth energy interaction path formed by the active and reactive subsystems of different grid-type converters are obtained. Combining the energy interaction processes of the first, second, third, and fourth energy interaction paths, the network model of the interconnected system is constructed.

[0102] The energy expressions for the interaction paths between the subsystems are shown below:

[0103]

[0104] Standalone machine-to-network interaction path V i_t_pq V j_t_pq This interactive energy is mainly generated by the self-interaction of the active and reactive power control subsystems within each grid-connected converter. This energy is only related to the response of the control state variables of each unit and the unit's connection location, reflecting the damping effect of the interaction of the internal control links of each grid-connected converter on grid disturbances. Therefore, it is also used in this paper to characterize the interaction between the grid and the generator.

[0105] Inter-system active power subsystem interaction path V ij_t_ppThis interactive energy is generated by the interaction between the active power control subsystems of different grid-connected converters, and is mainly influenced by the state variable Δθ of the active power control loop. i and Δθ j The impact of the response.

[0106] Inter-machine reactive power subsystem interaction path V ij_t_qq This interactive energy is generated by the interaction between the reactive power control subsystems of different grid-connected converters, and is mainly influenced by the state variable response ΔV of the reactive power control link. i and ΔV j The impact.

[0107] Inter-system active-reactive power interaction path V ij_t_pq This interactive energy is generated by the cross-coupling between the active and reactive power control subsystems of different grid-connected converters, and is simultaneously affected by the state variables ΔV of the active and reactive power control links. i , ΔV j , Δθ i , Δθ j Influence.

[0108] At this point, the interaction mechanism of the interconnected grid converter system is studied, and the "interaction energy coefficient" is defined as a metric to quantify the effect of each interaction path on mitigating or aggravating system oscillation.

[0109] First, for each grid-type converter in the interconnected system, the stored energy generated by power coupling in the grid-type converter is obtained according to its dynamic energy function model. Then, the rate of change of the stored energy in the grid-type converter is obtained according to Lyapunov's second stability theorem. Based on this rate of change, the aperiodic component of each energy term in the dynamic energy function model of the grid-type converter is obtained. Finally, based on the aperiodic component of each energy term in the dynamic energy function models of multiple grid-type converters in the interconnected system, the interaction energy coefficient of each energy interaction path in the interconnected system is determined.

[0110] In practical implementation, according to Lyapunov's second stability theorem, in an energy-conservative system, after a disturbance, the state variables will deviate from the stable operating point, generating stored energy. If this stored energy can be gradually dissipated over time, the system oscillation amplitude will gradually decrease, eventually reaching a stable state. Conversely, if the stored energy gradually increases after a disturbance, the system oscillation will gradually diverge and become unstable. Combining the dynamic energy expression of a grid-type converter, the rate of change of the system's stored energy in the constructed energy-conservative system can be expressed as:

[0111]

[0112] In the formula, K i and K jK is the set of dissipative energy coefficients. ij It is a set of interaction energy coefficients.

[0113] For each grid-type converter in the interconnected system, the aperiodic components of the stored energy, dissipated energy, and interactive energy of the grid-type converter are obtained according to the voltage and phase angle of the grid-type converter. Based on the aperiodic components of the dissipated energy and interactive energy of each grid-type converter, an interactive energy coefficient is obtained to reflect whether the aperiodic component of the stored energy of each grid-type converter in the interconnected system is dissipated or accumulated.

[0114] In practical implementation, when the system is disturbed, the oscillation mode α+jω is excited. c State variable Δx i It can be represented as: Substituting this expression into the dynamic energy expression of the grid-type converter and extracting the aperiodic components of each energy term yields:

[0115]

[0116] It can be seen that as the stored energy gradually increases, λ s If α > 0, the real part of the characteristic root α > 0, and the system oscillates and diverges. Conversely, if λ > 0, the system oscillates and diverges. s If λ > 0 and α < 0, the system will gradually converge to a stable state; therefore, the coefficient of change in stored energy and the eigenvalues ​​show consistent changes. s Furthermore, based on the dissipation coefficient λ d and interaction coefficient λ t Composition. λ d Since λ is always negative, it makes a positive damping contribution to the system; therefore, λ s The sign depends primarily on the interaction coefficient λ. t The size of λ. t If the value is greater than 0, the interaction between subsystems in the system will contribute to the accumulation of system storage energy, which is detrimental to system stability, and λ t The larger λ is, the greater the negative damping effect of the interaction. Conversely, if λ is smaller... t When the value is less than 0, the interaction in the system exhibits a positive damping effect, which is conducive to the rapid dissipation of stored energy and accelerates the convergence of system oscillations.

[0117] Therefore, the interaction energy coefficient λ generated by analyzing the four energy interaction paths is... t It can quantitatively characterize the damping contribution of the interaction of each subsystem to the stability of machine-network and inter-machine oscillations.

[0118] Step 104: Given that the grid-type converters in the interconnected system are located in different installation positions and / or the grid-type converters use different control parameters, different configuration schemes for multiple grid-type converters in the interconnected system are obtained. By acquiring the interaction energy coefficients of the interconnected system corresponding to different configuration schemes, the optimal configuration of multiple grid-type converters is determined.

[0119] In one example, the optimal configuration of multiple grid converters includes: the power control response bandwidth of the grid converter transmitting power is greater than the power control response bandwidth of the grid converter receiving power.

[0120] In one example, the different configuration schemes of multiple grid-type converters in the interconnected system are as follows: the grid-type converters in the interconnected system are located in different installation positions, and / or the grid-type converters use different control parameters, and / or the lines between multiple grid-type converters use different structural parameters.

[0121] Specifically, for the first energy interaction path between the active and reactive subsystems of each grid-type converter, the aperiodic components of the stored energy, dissipated energy, and interaction energy of the grid-type converter are extracted based on the voltage and phase angle of the grid-type converter to obtain the interaction energy coefficient of the first energy interaction path; for the second energy interaction path between the active subsystems of different grid-type converters, the aperiodic components of the stored energy, dissipated energy, and interaction energy of the grid-type converter are extracted based on the phase angle of each grid-type converter corresponding to the second energy interaction path to obtain the interaction energy coefficient of the second energy interaction path; for different For the third energy interaction path between the reactive subsystems of the grid-type converter, the aperiodic components of the stored energy, dissipated energy, and interaction energy of the grid-type converter are extracted based on the voltage of each grid-type converter corresponding to the third energy interaction path to obtain the interaction energy coefficient of the third energy interaction path. For the fourth energy interaction path between the active and reactive subsystems of different grid-type converters, the aperiodic components of the stored energy, dissipated energy, and interaction energy of the grid-type converter are extracted based on the voltage and phase angle of each grid-type converter corresponding to the fourth energy interaction path to obtain the interaction energy coefficient of the fourth energy interaction path.

[0122] In practical implementation, regarding the energy coefficient analysis of single-machine-network interaction, the time-domain expression of the state variable is substituted into V. i_t_pq From the expression, and by extracting the interaction energy coefficient from its aperiodic components, the single-machine-network interaction energy coefficient λ can be obtained. i_t_pq expression:

[0123]

[0124] It can be seen that λ i_t_pq Mainly composed of the state variables Δθ of each grid converter itself.i and ΔV i The response is determined, and its value (positive or negative) depends on the following three parameters.

[0125] (1)f p1,i

[0126] From the dynamic energy model formula of the active power control subsystem of the grid-type converter, it can be seen that fp1,i is only related to the converter's stable operating point parameters and the line structure parameters. Substituting the equilibrium point power expression into fp1,i, we get:

[0127]

[0128] In the formula, y ij Let Re(·) be the equivalent admittance between unit i and unit j, and let Re(·) be the real part of the admittance, i.e., the conductance parameter.

[0129] From this formula, we can obtain f p1,i It is always a positive value.

[0130] (2)

[0131] The voltage and phase angle oscillation response phase of the grid-type converter mainly depend on the interaction between the active and reactive power control loops. This is derived by substituting the expression for the flowing power on the transmission line from unit i to Bus A into the first-order differential equation of the reactive power loop. The transfer function expression between the voltage and phase angle oscillation components of unit i is:

[0132]

[0133] In the formula, f q1,i >0, the power loop control parameters only change the magnitude of the phase difference, not the range of the phase difference interval. The range of the interval is only related to f q2,i The positive and negative correlation. If f q2,i <0, sin(·)<0, cos(·)>0. If f q2,i >0, sin(·)>0, cos(·)<0.

[0134] (3)f q2,i

[0135] From the above formulas, we can see that f q2,i The sign of f affects both the amplitude coefficient and the phase coefficient. q2,i It is only related to the converter's stable operating point parameters and line structure parameters. Substituting the initial power expression into f q2,i In the meantime, and combined with the Y-Δ transformation of the line, we can obtain:

[0136]

[0137] In the formula, Let g represent the sum of the equivalent conductances of the remaining generating units interconnected with the i-th generating unit at a distance from the i-th generating unit. _sum,i .

[0138] It can be seen that f q2,i The sign depends primarily on the interconnect system structure and conductivity parameters. Definition Let g be the equivalent steady-state conductance of the i-th unit. eq_i The variation law of the single-machine network interaction energy coefficient can be obtained as follows:

[0139] When g eq_i <g _sum,i That is, f q2,i <0,,λ i_t_pq If the value is positive, it means that the active-reactive coupling of the i-th converter has a negative damping contribution to the grid oscillation, which helps to increase energy accumulation and aggravates the divergence of system oscillation.

[0140] When g eq_i >g _sum,i That is, f q2,i >0, ω c The term in question is negative, and its large value dominates; therefore, λ i_t_pq The overall value is negative, which has a positive dissipation effect on system oscillation. The power coupling inside the converter has a positive damping effect on grid oscillation, which is beneficial to the stability of system oscillation.

[0141] In summary, the sign of the single-unit grid interaction energy coefficient is primarily determined by the line structure parameters of the interconnection system. Control parameters only change the magnitude of this interaction, not the positive or negative dissipation properties. Therefore, when designing multi-grid converter layouts, it is crucial to consider the connection distance between units and the grid structure to ensure the equivalent steady-state conductance g of each unit. eq_i Greater than the equivalent conductance parameter g of the line _sum,i This is to prevent oscillation and instability caused by machine-network interaction.

[0142] Regarding the analysis of the inter-machine interaction energy coefficient of multi-grid converters, Δθ i and Δθ j Substituting the state variable response into V ij_t_pp And solve for the aperiodic components, deriving the interaction coefficient λ. ij_t_pp The expression is:

[0143]

[0144] It can be seen that if the equivalent reactance between two converters is much greater than the resistance, Re(Y) ijWhen the effective resistance between the two converters is approximately 0, the inter-converter active power interaction coefficient is close to 0, meaning the power subsystems between the converters are relatively decoupled and will not affect system stability. However, when the equivalent resistance between the two converters cannot be ignored, Re(Y) ≈ 0. ij )≠0, there is active power interaction between the two units, and its sign depends on the steady-state phase angle difference between the two units, sin(θ). i0 -θ j0 and oscillation phase difference

[0145] (1)sin(θ i0 -θ j0 )

[0146] θ i0 -θ j0 In steady state, the phase angle difference between units i and j, its sign indicating the sending and receiving ends positions of the two units. If θ i0 -θ j0 If the value is greater than 0, then active power flows from unit i to unit j, meaning unit i is at the sending end and unit j is at the receiving end, and vice versa.

[0147] (2)

[0148] Let be the oscillating phase difference caused by the phase angles of units i and j, the value of which depends on the active power control loop parameters between the units. It can be derived that:

[0149]

[0150] F i Substituting the expression into the transfer function expression between the voltage and phase angle oscillation components of unit i, we get:

[0151]

[0152] In the formula, ω bp This is the response bandwidth of the active power control loop of the converter.

[0153] Based on the above parameter analysis, when unit i is at the sending end and unit j is at the receiving end, sin(θ) i0 -θ j0 If D > 0, then pi >D pj That is, the active ring bandwidth ω bpi >ω bpj ,but λ ij_t_pp A value greater than 0 indicates that the active power interaction between generators exhibits a negative dissipation effect on inter-generator oscillations, which is detrimental to system stability. In other words, the faster the active power loop response of the sending-end units, the more detrimental it is to inter-generator oscillation stability. Furthermore, influenced by Re(Y)... ijThe greater the equivalent conductance between machines, the greater the negative damping effect generated by active power interaction.

[0154] Regarding the energy interaction analysis of the reactive power subsystem between machines, ΔV i and ΔV j Substituting the state variable response into V ij_t_qq And solve for the aperiodic components, deriving the interaction coefficient λ. ij_t_qq The expression is:

[0155]

[0156] It is known that the interaction coefficient of the reactive subsystem comprises two parts dominated by the inter-system equivalent conductance and equivalent susceptance. This paper focuses on the interconnection system at the same voltage level; therefore, V i0 and V j0 The difference between them is small, λ ij_t_qq Mainly composed of the equivalent susceptance between the machine and the y ij The term in question is dominant, and its sign depends on cos(θ). i0 -θ j0 )and

[0157] (1)cos(θ i0 -θ j0 )

[0158] Considering that the phase angle difference between units is small in steady-state scenarios, not exceeding 90 degrees, therefore cos(θ) i0 -θ j0 )>0.

[0159] (2)

[0160] It depends on the difference in phase of the voltage oscillations at ports i and j of the unit. It can be derived that:

[0161]

[0162] but, The expression is:

[0163]

[0164] In the formula, ω bq This is the response bandwidth of the converter's reactive power control loop.

[0165] Due to ω bq >0, Furthermore, the closer the reactive power control bandwidth parameters of the two generating units are set, the better. The larger the value, the better.

[0166] Based on the above parameters, the interaction coefficient λ generated by the inter-machine reactive power control subsystem can be determined. ij_t_qq A constant negative value has a positive dissipative effect on the accumulation of stored energy in the system, which is conducive to the rapid convergence of system oscillations. Furthermore, the closer the bandwidth of the reactive power control links between units, the more positive damping effect this interaction path generates, thus improving the stability of the system.

[0167] Regarding the energy interaction analysis of the active-reactive subsystem between generator units, the energy interaction between the active-reactive subsystem is influenced by both the unit phase angle and voltage state variables. Let Δθ i , Δθ j ΔV i and ΔV j Substituting the oscillating component into V ij_t_pq From this, and by extracting the derivative coefficients of the aperiodic quantities, we can obtain:

[0168]

[0169] It can be seen that λ ij_t_qq There are coefficient terms dominated by the inter-machine equivalent conductance and susceptance, respectively. Subject to ω c The influence of numerical values, the equivalent susceptance between machines Im(y) ij The term containing ) is in λ ij_t_qq The middle is dominant, and λ ij_t_qq The sign depends primarily on the steady-state phase angle difference between the two units, sin(θ). i0 -θ j0 ), and the phase difference between Δθ and ΔV. Wherein, sin(θ) i0 -θ j0 It mainly depends on the location of the unit connected to the sending and receiving ends. It is mainly affected by the unit's control parameters. Furthermore, it can be calculated that... The expression is:

[0170]

[0171] It can be seen that when unit i is at the sending end, if D pi >D pj Or Dqi>Dqj, that is, the active or reactive power control bandwidth ω bpi >ω bpj ,but λ ij_t_pq >0. The interaction between the active and reactive subsystems between generators has a negative dissipative effect on the system, which is detrimental to system oscillation convergence. In other words, the faster the response of the active or reactive control loop of the sending-end unit, the more detrimental it is to the stability of inter-generator oscillations.

[0172] Based on the analysis of the three inter-machine interaction paths described above, the inter-machine interaction process mainly exists in the active subsystem interaction and active-reactive subsystem interaction paths. Its damping effect depends on the relative positions of the converters connected to the sending and receiving ends, and their relative power loop response bandwidths. If the power loop response bandwidth of the sending unit is greater than that of the receiving unit, both the active subsystem interaction and the active-reactive subsystem interaction processes will increase the system disturbance energy, causing system oscillations to diverge. Although the reactive subsystem interaction process exhibits a positive dissipation effect, its value is relatively small, and its damping effect on inter-machine oscillations is also relatively small.

[0173] Therefore, this embodiment can provide a configuration principle for multi-network converters aimed at oscillation stability in interconnected systems, as described below:

[0174] First, the grid structure of the multi-grid converter is designed to ensure the steady-state conductance parameter g of each grid converter. eq_i Greater than the total equivalent conductance parameter g of the interconnection line _sum,i First, to prevent oscillation and instability caused by single-machine-network interaction. Second, according to the power flow distribution of the grid, the control parameters of the grid converters are configured to increase the power control bandwidth of the receiving-end units, avoiding oscillation and instability caused by negative damping interaction between units, thereby ensuring the stable operation of the multi-grid converter interconnection system.

[0175] In this embodiment, addressing the oscillation and instability problem in an interconnected system composed of multiple grid-type converters, an interaction energy coefficient is defined based on the energy interaction between the multiple grid-type converters during power coupling. The interaction energy coefficient indicates whether the stored energy generated by power coupling between the multiple grid-type converters in the interconnected system will gradually dissipate or increase over time. If the stored energy gradually dissipates over time, the oscillation amplitude of the interconnected system will gradually decrease, eventually reaching a stable state. If the stored energy gradually increases over time, the oscillation amplitude of the interconnected system will gradually increase, gradually leading to instability. Therefore, the interaction energy coefficient quantifies the effect of the energy interaction between the multiple grid-type converters on mitigating or exacerbating the oscillation of the interconnected system. Furthermore, different configuration schemes are represented by the grid-type converters being installed in different locations and / or using different control parameters. By obtaining the interaction energy coefficients corresponding to different configuration schemes, the effect of the energy interaction between the multiple grid-type converters in different configuration schemes on mitigating or exacerbating the oscillation of the interconnected system can be determined. Based on this, the optimal configuration of multiple grid-connected converters can be determined, resulting in a configuration scheme that has a significant effect on mitigating the oscillations of the interconnected system. This solves the problem of multi-mode oscillation instability caused by large-scale grid-connected converters being connected to the grid under low-impedance grid conditions.

[0176] In one embodiment, to verify the accuracy of the interaction mechanism of the multi-grid converter interconnection system proposed in this invention, an equivalent three-grid converter interconnection system was built in Matlab / Simulink. The system structure is as follows: Figure 2 As shown in Table 1, the basic parameters of the grid-type converter are as follows.

[0177] Table 1

[0178]

[0179] To verify the impact of grid-connected converter access distance on the system grid oscillation stability, simulations were conducted with four different line structure parameters: g _sum,i =1.04, 1.12, 1.28, 1.43. The simulation curves are as follows: Figure 7 As shown.

[0180] Depend on Figure 3 It can be seen that, with g _sum,i As g increases, the system's oscillation convergence trend gradually slows down. _sum,i When the value is greater than 1.25, the oscillation changes from convergence to divergence. _sum,i When g = 1.28, the system oscillates approximately with constant amplitude. _sum,i When the value increases to 1.43, the system oscillates and diverges until it becomes unstable.

[0181] Furthermore, the energy change trajectory of machine-network interaction in these four scenarios is depicted, such as... Figure 4 As shown in the diagram. Point A→B: Machine-network interaction energy shows a rapid downward trend, which is conducive to the rapid consumption of accumulated system energy. Point B→C: Machine-network interaction energy still shows a spiral downward trend, but the rate of decline has slowed significantly. Point C→D: Machine-network interaction energy spirals upward and gradually increases, which has a boosting effect on system storage energy. Point D→E: Machine-network interaction energy growth accelerates, and the trend of storage energy dispersion is obvious.

[0182] To reduce the impact of machine-network interaction on the analysis results, the structural parameters of the interconnected system are set to satisfy g. _sum,i <g eq,i The scenario involves adjusting the connection positions of each unit so that unit 1 is at the sending end, while units 2 and 3 are at the receiving end.

[0183] First, adjust the active power control damping coefficients of Unit 1 and Unit 2 to change the unit power control response bandwidth, and calculate λ respectively. ij_t_pp , λ ij_t_pq , λ ij_t_qq ,like Figure 5 As shown.

[0184] Depend on Figure 5(a) It can be seen that when the control parameters of the two generating units are the same, there is no active power interaction between them. However, when the active power control parameter of the sending-end generating unit 1 is greater than that of the receiving-end generating unit 2, that is, when the response bandwidth of unit 1 is greater than that of unit 2, λ ij_t_pp When the value becomes positive, the interaction of the active subsystems will have a negative damping effect on the system oscillation, and it is very easy to cause inter-system oscillation instability.

[0185] Figure 5 (b) The variation trend of the interactive energy coefficient of the inter-machine reactive power subsystem under different reactive power control parameters is presented. As shown in the figure, the difference in parameters of the inter-machine reactive power control link does not change λ. ij_t_qq The positive and negative properties of λ indicate that the reactive power subsystem interaction always exhibits a positive dissipation effect, which is beneficial to system stability. Furthermore, the closer the reactive power control parameters of the two units are, the greater the λ becomes. ij_t_qq The larger.

[0186] Figure 5 (c) The variation trend of the active-reactive subsystem interaction energy coefficient under different active power control parameters is given. When the active power control parameters of Unit 1 are large and the response speed is fast, λ ij_t_pq The value will turn positive, indicating that inter-system interaction is detrimental to system oscillation stability. Furthermore, comparing the values ​​in the three figures reveals that interaction between the active subsystem and the active-reactive subsystem plays a dominant role and is the key factor affecting the stability of inter-system oscillations.

[0187] Furthermore, simulations were conducted by setting different active power control parameters between the units, and the results were compared with theoretical results to prove the accuracy of the interaction law between the units. The set parameters and simulation curves are shown below. Figure 6 As shown.

[0188] Figure 6 In (a), when the control parameters of both units are the same, the inter-unit interaction energy is relatively small, and the interaction is mainly between the generator and the grid. Furthermore, the structural parameters of the interconnected system do not meet the conditions for grid oscillation instability, resulting in system oscillation convergence. If the active power control parameters of receiving-end unit 2 are increased, the inter-unit interaction will exhibit a positive dissipative effect, causing the system oscillation to converge further to stability. If the active power control parameters of sending-end unit 1 are increased, the inter-unit interaction will exhibit a negative dissipative effect, causing the system oscillation to change from convergence to divergence, gradually leading to instability.

[0189] Figure 6 (b) and Figure 6 (c) Simulation scenario involving a single increase in the control parameters of the sending and receiving ends. If the active power control parameters of the sending unit are continuously increased, making its response rate greater than that of the receiving unit, the negative dissipation effect generated by the inter-unit interaction will gradually intensify, and the system oscillation divergence will become increasingly severe. Conversely, if the active power control parameters of the receiving unit are increased to be greater than those of the sending unit, the inter-unit interaction will exhibit a positive dissipation effect, and the system oscillation will gradually converge to stability.

[0190] To verify the consistency between the energy change and the simulation, D is taken as... p1 =5.4,D p2 =3.6 and D p1 =3.6,D p2 =5.4, these two sets of parameters characterize the trajectory of energy change between the machines as follows Figure 7 and Figure 8 As shown.

[0191] Depend on Figure 7 It can be seen that when the control response speed of the sending-end converter is greater than that of the receiving-end converter, both the active subsystem interaction and the active-reactive subsystem interaction exhibit a spiral upward trend. These two interaction paths both have a negative damping effect on system oscillation. The reactive subsystem interaction exhibits a spiral downward change, which helps dissipate energy, but its value is much smaller than that of the other two interaction paths. Therefore, the overall energy of inter-machine interaction shows an upward trend.

[0192] Figure 8 In the process, when the control response speed of the sending-end converter is less than that of the receiving-end converter, the change trend of reactive subsystem interaction energy does not change, while the interaction of active subsystem and active-reactive subsystem both show a spiral downward trend. At this time, the three inter-machine interaction paths all have a positive dissipation effect on system oscillation, which is conducive to the stability of system oscillation.

[0193] The steps of the various methods described above are only for clarity. In practice, they can be combined into one step or some steps can be split into multiple steps. As long as they include the same logical relationship, they are all within the protection scope of this invention. Adding insignificant modifications or introducing insignificant designs to the algorithm or process, without changing the core design of the algorithm and process, are also within the protection scope of this invention.

[0194] Another embodiment of the present invention relates to an optimized configuration device for a multi-grid converter. The implementation details of this optimized configuration device are described below. The following details are provided for ease of understanding and are not essential for implementing this solution. The optimized configuration device for the multi-grid converter in this embodiment includes:

[0195] The model building module is used to build a mathematical model of the interconnected system based on the power coupling between multiple grid-type converters in the interconnected system.

[0196] The energy interaction module is used to obtain the energy interaction of multiple grid-type converters in the power coupling process of the interconnected system based on the mathematical model of the interconnected system.

[0197] The oscillation analysis module is used to define the interaction energy coefficient of an interconnected system to quantify the effect of energy interaction between multiple grid-type converters on mitigating or aggravating oscillations in the interconnected system.

[0198] Among them, the interaction energy coefficient is used to indicate whether the stored energy generated by the power coupling between multiple grid-type converters in the interconnected system will gradually dissipate or increase over time. If the stored energy will gradually dissipate over time, the oscillation amplitude of the interconnected system will gradually decrease and eventually reach a stable state. If the stored energy will gradually increase over time, the oscillation amplitude of the interconnected system will gradually increase and gradually diverge and become unstable.

[0199] The optimization configuration module is used to determine the optimal configuration of multiple grid-type converters in an interconnected system, based on different installation locations of grid-type converters in the interconnected system, and / or different control parameters for grid-type converters, and / or different structural parameters for the lines between multiple grid-type converters. By obtaining the interaction energy coefficient of the interconnected system corresponding to different configuration schemes, the module determines the optimal configuration of multiple grid-type converters.

[0200] It is not difficult to see that this embodiment is a device embodiment corresponding to the above method embodiments, and this embodiment can be implemented in conjunction with the above method embodiments. The relevant technical details and technical effects mentioned in the above embodiments are still valid in this embodiment, and will not be repeated here to reduce repetition. Accordingly, the relevant technical details mentioned in this embodiment can also be applied to the above embodiments.

[0201] It is worth mentioning that all modules involved in this embodiment are logical modules. In practical applications, a logical unit can be a physical unit, a part of a physical unit, or a combination of multiple physical units. Furthermore, to highlight the innovative aspects of this invention, this embodiment does not introduce units that are not closely related to solving the technical problem proposed by this invention; however, this does not mean that other units are absent from this embodiment.

[0202] Another embodiment of the present invention relates to a computer device, comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the optimized configuration method of the multi-network converter in the above embodiments.

[0203] The memory and processor are connected via a bus, which can include any number of interconnecting buses and bridges, connecting various circuits of one or more processors and memories. The bus can also connect various other circuits, such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art and will not be described further herein. The bus interface provides an interface between the bus and the transceiver. The transceiver can be a single element or multiple elements, such as multiple receivers and transmitters, providing a unit for communicating with various other devices over a transmission medium. Data processed by the processor is transmitted over the wireless medium via an antenna, which further receives data and transmits it to the processor.

[0204] The processor manages the bus and general processing, and also provides various functions, including timing, peripheral interfaces, voltage regulation, power management, and other control functions. Memory is used to store data used by the processor during operation.

[0205] Another embodiment of the present invention relates to a computer-readable storage medium storing a computer program. When executed by a processor, the computer program implements the method embodiments described above.

[0206] That is, those skilled in the art will understand that all or part of the steps in the methods of the above embodiments can be implemented by a program instructing related hardware. This program is stored in a storage medium and includes several instructions to cause a device (which may be a microcontroller, chip, etc.) or processor to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0207] Those skilled in the art will understand that the above embodiments are specific embodiments for implementing the present invention, and in practical applications, various changes can be made to them in form and detail without departing from the spirit and scope of the present invention.

Claims

1. A method for optimizing the configuration of a multi-network converter, characterized in that, The method includes: Based on the power coupling effect between multiple grid-type converters in an interconnected system, a mathematical model of the interconnected system is constructed. Based on the mathematical model of the interconnected system, a network model of the interconnected system is constructed to describe the energy interaction process of multiple grid-type converters during power coupling; wherein, the network model of the interconnected system is used to reflect the stored energy and dissipated energy generated by each grid-type converter independently, as well as the interactive energy generated during power coupling. Based on the dissipated energy and interactive energy of each grid converter, obtain the interactive energy coefficient to reflect whether the stored energy of each grid converter in the interconnected system is dissipated or accumulated. Given that the grid-type converters in the interconnected system are located in different installation positions and / or the grid-type converters use different control parameters, the optimal configuration of multiple grid-type converters in the interconnected system is determined by obtaining the interaction energy coefficient of the interconnected system corresponding to different configuration schemes. The interaction energy coefficient is determined by the following formula: ； In the formula, , and These are stored energy, dissipated energy, and interacting energy, respectively. K i and K j For the set of dissipation energy coefficients, K ij This is a set of interactive energy coefficients; as the stored energy gradually increases, λ s >0, real part of characteristic root α >0 indicates the interconnected system is oscillating and diverging; conversely, >0 indicates the interconnected system is oscillating and diverging. λ s >0, α If the value is less than 0, the interconnected system will gradually converge to a stable state. λ s From dissipation coefficient λ d and interaction coefficient λ t composition, λ d The value is always negative, thus contributing positive damping to the system. λ t >0, the interaction process between subsystems in an interconnected system will contribute to the accumulation of system storage energy, which is detrimental to system stability, and λ t The larger the value, the greater the negative damping effect of the interaction; conversely, if... λ t <0, the interaction in the interconnected system exhibits a positive damping effect, which is conducive to the rapid dissipation of stored energy and accelerates the convergence of system oscillations; By exciting oscillatory modes after the system is disturbed α + jω c , will the state variable Δ x i = A xi e αt cos ( ω c t+φ xi Substituting these values ​​into the following dynamic energy expression for a grid-type converter, and extracting the aperiodic components of each energy term, we obtain: ； ； In the formula, V i_s For the first i Total stored energy generated by the unit. V i_d For the first i The dissipated energy generated by the generator unit characterizes its damping effect on the system's oscillating energy. V i_t For the first i The internal control links of the unit and their relationship with the first j Interactive energy between control components of the generator set. , For reactive power generator-grid interaction coefficient, , This represents the interaction coefficient between active power units; The interaction energy coefficients generated by the following four energy interaction paths are used to quantitatively characterize the damping contribution of each subsystem interaction to the stability of machine-network and inter-machine oscillations: Single-machine network interaction energy coefficient λ i_t_pq : ； Inter-machine interaction energy coefficient of multi-grid converter λ ij_t_pp : ； Inter-system reactive power coefficient λ ij_t_qq : ； Interactive energy coefficient of active-reactive subsystem between machines V ij_t_pq : ； In the formula, A vi and A θi For the first i Assigning values ​​to voltage and phase angle oscillation components of grid-connected generator units. The oscillation frequency is... For the first i The phase angle difference between the output voltage and phase angle oscillation components of the grid-type generator set.

2. The optimized configuration method for multi-network converters according to claim 1, characterized in that, The mathematical model of the interconnected system, based on the power coupling effect among multiple grid-type converters in the interconnected system, includes: For each grid-type converter in the interconnected system, based on the active-phase angle outer loop control module and the reactive-voltage outer loop control module of the grid-type converter, the active-phase angle outer loop control model and the reactive-voltage outer loop control model of the grid-type converter are established respectively. Based on the grid connection structure of multiple grid-type converters, and according to the active-phase angle outer loop control model and reactive-voltage outer loop control model of the grid-type converters, the active power and reactive power transmitted by each grid-type converter to the common bus, and the active power and reactive power transmitted by the common bus to each grid-type converter are obtained respectively. A mathematical model of the interconnected system is constructed based on the active and reactive power transmitted by each of the multiple grid-type converters to the common bus, and the active and reactive power transmitted by the common bus to each of the multiple grid-type converters.

3. The optimized configuration method for multi-network converters according to claim 1, characterized in that, The optimal configuration of the multiple grid converters includes: the power control response bandwidth of the grid converter transmitting power is greater than the power control response bandwidth of the grid converter receiving power.

4. The optimized configuration method for multi-network converters according to claim 1, characterized in that, The different configuration schemes of multiple grid-type converters in the interconnection system are as follows: the grid-type converters in the interconnection system are located in different installation positions, and / or the grid-type converters adopt different control parameters, and / or the lines between multiple grid-type converters adopt different structural parameters.

5. An optimization configuration apparatus for a multi-grid converter, using the optimization configuration method for a multi-grid converter as described in any one of claims 1 to 4, characterized in that, The device includes: The first model construction module is used to construct a mathematical model of the interconnected system based on the power coupling effect between multiple grid-type converters in the interconnected system. The second model construction module is used to construct a network model of the interconnected system based on the mathematical model of the interconnected system, which describes the energy interaction process of multiple grid-type converters during power coupling; wherein, the network model of the interconnected system is used to reflect the stored energy and dissipated energy generated by each grid-type converter, as well as the interactive energy generated during power coupling. The energy analysis module is used to obtain the interaction energy coefficient, which reflects whether the energy stored in each grid converter in the interconnected system is dissipated or accumulated, based on the dissipated energy and interaction energy of each grid converter. The optimization configuration module is used to determine the optimal configuration of multiple grid-type converters in an interconnected system, based on different installation locations of grid-type converters in the interconnected system, and / or different control parameters for grid-type converters, and / or different structural parameters for the lines between multiple grid-type converters. By obtaining the interaction energy coefficient of the interconnected system corresponding to different configuration schemes, the module determines the optimal configuration of multiple grid-type converters.

6. A computer device, characterized in that, include: At least one processor; And a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the optimized configuration method of the multi-network converter as described in any one of claims 1 to 4.

7. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the optimized configuration method for the multi-network converter as described in any one of claims 1 to 4.

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