Optimal configuration method, device and equipment of multi-network-construction converter and medium

Abstract

The invention relates to the technical field of wind power generation, and discloses an optimal configuration method, device and equipment of a multi-network-construction converter and a medium. The method comprises the following steps: constructing a mathematical model of an interconnection system according to a power coupling effect among a plurality of network construction type converters in the interconnection system formed by the plurality of network construction type converters; according to the mathematical model of the interconnection system, constructing a network model of the interconnection system, wherein the network model is used for describing the energy interaction process of the plurality of network construction type converters during power coupling; according to the dissipated energy and the interactive energy of each network-forming converter, obtaining an interactive energy coefficient for reflecting whether the stored energy of each network-forming converter in the interconnection system is dissipated or accumulated; the optimal configuration of the plurality of network-building type converters is determined according to different configuration schemes of the plurality of network-building type converters in different installation positions of the network-building type converters in the interconnection system and / or different control parameters adopted by the network-building type converters by acquiring interaction energy coefficients corresponding to the different configuration schemes.

Description

Technical Field

[0001] The present invention relates to the technical field of wind power generation, and in particular to an optimization configuration method, device, equipment and medium for a multi-grid converter. Background Art

[0002] The new power system shows a "double high" development trend of high proportion of new energy and high proportion of power electronics, while the proportion of synchronous generators is gradually decreasing, resulting in the low anti-interference ability of the power grid with weak damping and weak support. In order to ensure the stable operation of the new power system in the future, it is necessary to introduce a grid-forming converter with voltage source properties to support the voltage and inertia of the power grid and improve the anti-interference ability of the system.

[0003] However, the access of large-scale grid-forming converters to the grid is equivalent to the existence of multiple voltage sources operating in parallel. There is mutual coupling between multiple grid-forming control instructions, which can easily lead to multi-modal oscillation instability problems in low-impedance grids. Summary of the invention

[0004] The purpose of the present invention is to provide a method, device, equipment and medium for optimizing the configuration of a multi-grid converter, which can solve the problem of multi-form oscillation instability caused by a large-scale grid-type converter connected to the grid in a low-impedance grid.

[0005] To solve the above technical problems, an embodiment of the present invention provides a method for optimizing configuration of a multi-network converter, comprising the following steps:

[0006] According to the power coupling effect between multiple grid-type converters in the interconnected system composed of multiple grid-type converters, a mathematical model of the interconnected system is constructed;

[0007] According to 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 storage energy and dissipated energy generated by each grid-type converter independently, as well as the interaction energy generated during power coupling;

[0008] According to the dissipated energy and interactive energy of each grid-type converter, an interactive energy coefficient is obtained to reflect whether the stored energy of each grid-type converter in the interconnected system is dissipated or accumulated;

[0009] Based on the fact that the mesh-type converters in the interconnected system are in different installation positions and / or the mesh-type converters use different control parameters, different configuration schemes of multiple mesh-type converters in the interconnected system are provided. By obtaining the interaction energy coefficients of the interconnected system corresponding to different configuration schemes, the optimal configuration of multiple mesh-type converters is determined.

[0010] Optionally, the method of constructing a mathematical model of an interconnected system based on a power coupling effect between multiple meshed converters in an interconnected system composed of multiple meshed converters includes:

[0011] For each grid-type converter in the interconnected system, an active-phase-angle outer-loop control model and a reactive-voltage outer-loop control model of the grid-type converter are established respectively according to the active-phase-angle outer-loop control module and the reactive-voltage outer-loop control module of the grid-type converter;

[0012] In combination with the grid-connected structure of multiple grid-type converters, according to the active-phase angle outer loop control model and reactive-voltage outer loop control model of the grid-type converter, 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 respectively obtained;

[0013] According to the active power and reactive power transmitted by each of the multiple grid-forming converters to the common bus, and the active power and reactive power transmitted by the common bus to the multiple grid-forming converters, a mathematical model of the interconnected system is constructed.

[0014] Optionally, each of the grid-type converters includes an active subsystem and a reactive subsystem, and the network model of the interconnected system for describing the energy interaction process of multiple grid-type converters during power coupling is constructed according to the mathematical model of the interconnected system, including:

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

[0016] A network model of the interconnected system is constructed by combining the energy interaction process of the first energy interaction path, the energy interaction process of the second energy interaction path, the energy interaction process of the third energy interaction path, and the energy interaction process of the fourth energy interaction path.

[0017] Optionally, obtaining the interaction energy coefficient for reflecting whether the stored energy of each grid-type converter in the interconnected system is dissipated or accumulated according to the dissipated energy and interaction energy of each grid-type converter includes:

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

[0019] According to the dissipated energy of each grid-type converter and the non-periodic component in the interactive energy, an interactive energy coefficient is obtained for reflecting whether the non-periodic component in the stored energy of each grid-type converter in the interconnected system is dissipated or accumulated.

[0020] Optionally, obtaining the interaction energy coefficient for reflecting whether the non-periodic component in the stored energy of each grid-type converter in the interconnected system is dissipated or accumulated according to the dissipated energy and the non-periodic component in the interaction energy of each grid-type converter includes:

[0021] For a first energy interaction path between an active subsystem and a reactive subsystem of each grid-type converter, extracting a non-periodic component of stored energy, dissipated energy and interaction energy of the grid-type converter according to a voltage and a phase angle of the grid-type converter to obtain an interaction energy coefficient of the first energy interaction path;

[0022] For the second energy interaction path between the active subsystems of different grid-type converters, according to the phase angle of each grid-type converter corresponding to the second energy interaction path, the non-periodic components in the stored energy, dissipated energy and interaction energy of the grid-type converter are extracted 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, extract the non-periodic components of the stored energy, dissipated energy and interactive energy of the grid-type converter according to the voltage of each grid-type converter corresponding to the third energy interaction path, so as to obtain the interactive energy coefficient of the third energy interaction path;

[0024] For the fourth energy interaction path between the active subsystems and reactive subsystems of different grid-type converters, the non-periodic components of the stored energy, dissipated energy and interaction energy of the grid-type converter are extracted according to 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.

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

[0026] Optionally, different configuration schemes of multiple meshed-type converters in the interconnected system are: the meshed-type converters in the interconnected system are at different installation positions, and / or the meshed-type converters adopt different control parameters, and / or the lines between multiple meshed-type converters adopt different structural parameters.

[0027] An embodiment of the present invention further provides an optimization configuration device for a multi-network converter, comprising:

[0028] A first model building module is used to build a mathematical model of an interconnected system according to a power coupling effect between multiple grid-forming converters in the interconnected system composed of multiple grid-forming converters;

[0029] The second model building module is used to build a network model of the interconnected system for describing the energy interaction process of multiple grid-type converters during power coupling according to the mathematical model of the interconnected system; wherein the network model of the interconnected system is used to reflect the storage energy and dissipated energy generated by each grid-type converter independently, as well as the interaction energy generated during power coupling;

[0030] An energy analysis module is used to obtain an interactive energy coefficient that reflects whether the stored energy of each grid-type converter in the interconnected system is dissipated or accumulated according to the dissipated energy and interactive energy of each grid-type converter;

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

[0032] An embodiment of the present invention also provides 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, and the instructions are executed by the at least one processor so that the at least one processor can execute the above-mentioned multi-grid converter optimization configuration method.

[0033] An embodiment of the present invention further provides a computer-readable storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the above-mentioned method for optimizing configuration of the multi-grid converter.

[0034] The optimization configuration method of the multi-grid converter provided by the present invention has at least the following beneficial effects:

[0035] In order to solve the problem of oscillation instability in an interconnected system composed of multiple mesh-type converters, the energy interaction process of multiple mesh-type converters in the interconnected system during power coupling is obtained, and the energy interaction process is reflected by the stored energy, dissipated energy and interactive energy of each mesh-type converter. Since in the interconnected system, the stored energy of the mesh-type converter will gradually dissipate or accumulate 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 accumulate over time, the oscillation amplitude of the interconnected system will gradually increase and gradually diverge and become unstable. Therefore, the present invention obtains an interactive energy coefficient that can reflect whether the stored energy of each mesh-type converter in the interconnected system is dissipated or accumulated through the dissipated energy and interactive energy of each mesh-type converter. Then, the interactive energy coefficient can reflect whether the energy interaction process between multiple mesh-type converters will slow down or aggravate the oscillation of the interconnected system.

[0036] At this time, the grid-type converters in the interconnected system are in different installation positions, and / or the grid-type converters use different control parameters, which are different configuration schemes for multiple grid-type converters in the interconnected system. 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 slow down or aggravate the oscillation of the interconnected system. Based on this, the optimal configuration of multiple grid-type converters can be determined, and a configuration scheme for slowing down the oscillation of the interconnected system can be obtained, thereby solving the problem of multi-form oscillation instability caused by large-scale grid-type converters connected to the power grid under low-impedance power grids. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] One or more embodiments are exemplarily described by the pictures in the corresponding drawings, and these exemplary descriptions do not constitute limitations on the embodiments.

[0038] Figure 1 is a flow chart of a method for optimizing configuration of a multi-network converter provided according to an embodiment of the present invention;

[0039] Figure 2 It is a schematic diagram of the structure of a multi-network converter interconnection system provided according to an embodiment of the present invention;

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

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

[0042] Figure 51 is a schematic diagram of a change trend of a random inter-group power control parameter of an inter-machine energy interaction coefficient provided according to an embodiment of the present invention, wherein (a) is an active subsystem interaction diagram, (b) is a reactive subsystem interaction diagram, and (c) is an active-reactive subsystem interaction diagram;

[0043] Figure 6 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 A D is provided according to an embodiment of the present invention. p1 =5.4,D p2 = 3.6, 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 A D is provided according to an embodiment of the present invention. p1 =3.6,D p2 = 5.4, where (a) is the active subsystem interaction diagram, (b) is the reactive subsystem interaction diagram, and (c) is the active-reactive subsystem interaction diagram. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings. However, it will be appreciated by those skilled in the art that in the embodiments of the present invention, many technical details are proposed in order to enable the reader to better understand the present invention. However, even without these technical details and various changes and modifications based on the following embodiments, the technical scheme claimed in the present invention can be implemented. The division of the following embodiments is for the convenience of description and should not constitute any limitation on the specific implementation of the present invention. The various embodiments can be combined and referenced with each other without contradiction.

[0047] An embodiment of the present invention relates to an optimization configuration method for a multi-grid converter. The implementation details of the optimization configuration method for the multi-grid converter of this embodiment are specifically described below. The following content is only the implementation details provided for easy understanding and is not necessary for implementing this solution.

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

[0049] Step 101 : constructing a mathematical model of an interconnected system according to a power coupling effect between multiple meshed converters in the interconnected system composed of the multiple meshed converters.

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

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

[0052] The active power-phase angle outer loop is usually used to simulate the swing equation of the synchronous generator. The second-order differential equation is written as:

[0053]

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

[0055] The reactive power loop usually adopts droop control to support the grid voltage by providing limited reactive power. Its first-order differential equation is:

[0056]

[0057] Where V i and V ref are the actual value and reference value of the PCC voltage output by the reactive loop, Q ref and Qi are the reactive power reference value and actual value of the grid-connected converter respectively; K i is the voltage integral coefficient; D q,i is the voltage droop coefficient.

[0058] Combined with the grid-connected structure of the grid-connected converter, in the above two formulas, the active power and reactive power generated by the i-th grid-connected converter can be expressed by the flow power on the transmission line from unit i to BusA, 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 are the equivalent conductance and susceptance of the unit’s iPCC point from the collecting bus A, respectively.

[0061] Substituting this formula into the above two formulas, the power control small signal model of the i-th grid-connected converter can be obtained as follows:

[0062]

[0063] In the formula,

[0064] A mathematical model of the interconnected system of multi-grid converters is established. Multi-grid converters mainly interact with each other through power. According to the line power transmission equation, the active and reactive power expressions transmitted from BusA to the i-th unit can be obtained as follows:

[0065]

[0066] Where P Ai and Q Ai are the active and reactive power transmitted by BusA to the i-th unit respectively.

[0067] Linearizing it yields:

[0068]

[0069] In the formula,

[0070] Furthermore, by combining the power balance equations at the common bus nodes, we can obtain the common bus voltage Δθ A and ΔV A The relationship between the terminal voltage and phase of each converter is:

[0071]

[0072] In the formula,

[0073] Substituting it into the small signal model of power control of the grid-type converter, the small signal model of the grid-type converter interconnection system with machine-to-machine interaction is obtained as follows:

[0074]

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

[0076] In the formula,

[0077]

[0078]

[0079] It can be seen from the formula that in addition to the internal voltage-phase coupling of the i-th grid-type converter, there is also a cross-coupling term between the state variables of the j-th grid-type converter, which corresponds to the machine-grid interaction and the machine-to-machine interaction. In order to further quantify the intensity of the machine-to-machine and machine-to-grid interaction of the multi-grid-type converter interconnection system, this paper constructs the interaction energy model of the grid-type converter interconnection system, and explicitly analyzes the influence of the grid-to-machine interaction of the grid-type converter on the system oscillation stability.

[0080] Step 102, based on the mathematical model of the interconnected system, construct a network model of the interconnected system for describing 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 storage energy and dissipated energy generated by each grid-type converter independently, as well as the interaction energy generated during power coupling.

[0081] In the specific implementation, according to the small signal model of the interconnected system of grid-type converters with inter-machine interaction, the i-th grid-type converter can be split into an active subsystem and a reactive subsystem, and the dynamic energy function models of the two control subsystems are established respectively using the first integration method.

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

[0083]

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

[0085] By using the first integration method, the second-order state variables are cross-multiplied, and the left and right integrations are performed to obtain the dynamic energy model expression of the active control subsystem of the i-th grid-connected converter:

[0086]

[0087] In the formula, f p1 , f p2 is the active machine-grid interaction coefficient, f p3 , f p4 are the interaction coefficients between active machines, which are related to the system structure parameters.

[0088]

[0089] The reactive power control subsystem state variable equation can be cross-multiplied by the first integration method to obtain the dynamic energy model expression of the reactive power control subsystem:

[0090]

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

[0092]

[0093] Combining the dynamic energy model expressions of the active control subsystem and the reactive control subsystem, the dynamic energy expression of the i-th grid-connected 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 is the total stored energy generated by the i-th unit, V i_d is the dissipated energy generated by the i-th unit, representing the damping effect on the system oscillation energy, V i_tis 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, by combining the small signal model of the grid-connected converter interconnection system with the interaction between machines, the partial derivative of this equation with respect to time can be obtained:

[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, which proves that the dynamic energy model of the i-th grid-type converter meets the energy conservation requirements. The storage energy and dissipated energy in the system are generated by the unit alone. The interactive energy of the i-th unit is generated by the coupling of the control links within the unit and the coupling between units, which is the energy link connecting multiple converters.

[0100] Furthermore, according to V i_t The state variables involved in each interactive energy determine the interaction object, and the four 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 inverter includes an active subsystem and a reactive subsystem. According to the mathematical model of the interconnected system, the energy interaction process of the first energy interaction path formed by the active subsystem and the reactive subsystem of each grid-type inverter, the energy interaction process of the second energy interaction path formed by the active subsystems of different grid-type inverters, the energy interaction process of the third energy interaction path formed by the reactive subsystems of different grid-type inverters, and the energy interaction process of the fourth energy interaction path formed by the active subsystems and reactive subsystems of different grid-type inverters are obtained; the energy interaction process of the first energy interaction path, the energy interaction process of the second energy interaction path, the energy interaction process of the third energy interaction path, and the energy interaction process of the fourth energy interaction path are combined to construct a network model of the interconnected system.

[0102] The energy expression of the interaction path between subsystems is as follows:

[0103]

[0104] Single machine network interaction path V i_t_pq , V j_t_pq , the interaction energy is mainly generated by the interaction of active and reactive control subsystems in each grid converter. This energy is only related to the control state variable response of each unit and the unit access position, reflecting the damping effect of the interaction of the internal control links of each grid converter on the grid disturbance. Therefore, it is also used to characterize the interaction between machines and grids in this paper.

[0105] Interactive path V between active subsystems ij_t_ppThe interactive energy is generated by the interaction between the active control subsystems of the different grid-connected converters and is mainly affected by the state variable Δθ of the active control link. i and Δθ j The impact of the response.

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

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

[0108] At this point, the interaction mechanism of the grid-type converter interconnection system is studied, and the "interaction energy coefficient" is defined as a measurement standard to quantify the effect of each interaction path on slowing down or aggravating system oscillations.

[0109] Firstly, for each grid-type converter in the interconnected system, the stored energy generated by the grid-type converter due to power coupling is obtained according to the dynamic energy function model of the grid-type converter. According to the second Lyapunov stability theorem, the change rate of the stored energy of the grid-type converter is obtained. According to the change rate of the stored energy of the grid-type converter, the non-periodic component of each energy item in the dynamic energy function model of the grid-type converter is obtained. According to the non-periodic component of each energy item in the dynamic energy function model 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 the specific implementation, according to Lyapunov's second stability theorem, in an energy conservative system, after the system is disturbed, each state variable will deviate from the stable operating point and generate stored energy. If the stored energy can be gradually dissipated over time, the system oscillation amplitude will gradually decrease and eventually reach a stable state. On the contrary, if the stored energy gradually increases after the system is disturbed, the system oscillation will gradually diverge and become unstable. Combined with the dynamic energy expression of the grid-type converter, it can be seen that in the constructed energy conservative system, the system stored energy change rate can be expressed as:

[0111]

[0112] In the formula, K i and K jis the set of dissipated energy coefficients, K ij is the set of interaction energy coefficients.

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

[0114] In the specific implementation, when the system is disturbed, the oscillation mode α+jω is excited. c , the state variable Δx i It can be expressed as: Substituting this expression into the dynamic energy expression of the grid-connected converter and extracting the non-periodic components of each energy term, we can obtain:

[0115]

[0116] It can be seen that when the stored energy gradually increases, λ s >0, the real part of the characteristic root α>0, the system oscillates and diverges. s >0, α<0, the system will gradually converge to stability, so the storage energy change coefficient has the same change consistency with the characteristic root. s And the dissipation coefficient λ d and the interaction coefficient λ t Composition. d is always negative, showing a positive damping contribution to the system, so λ s The positive or negative value depends mainly on the interaction coefficient λ t If λ t >0, the interaction process of each subsystem in the system will help increase the system storage energy accumulation, which is not conducive to system stability, and λ t The larger the value, the greater the negative damping effect of the interaction. t <0, the interaction in the system presents 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 , which can quantitatively characterize the damping contribution of each subsystem interaction to the stability of machine-grid and inter-machine oscillations.

[0118] Step 104, based on the mesh-type converters in the interconnected system being in different installation positions and / or the mesh-type converters using different control parameters, different configuration schemes of multiple mesh-type converters in the interconnected system are obtained, and the optimal configuration of the multiple mesh-type converters is determined by obtaining the interaction energy coefficients of the interconnected system corresponding to different configuration schemes.

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

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

[0121] Specifically, for the first energy interaction path between the active subsystem and the reactive subsystem of each grid-type converter, the non-periodic components in the stored energy, dissipated energy and interactive energy of the grid-type converter are extracted according to the voltage and phase angle of the grid-type converter to obtain the interactive energy coefficient of the first energy interaction path; for the second energy interaction path between the active subsystems of different grid-type converters, the non-periodic components in the stored energy, dissipated energy and interactive 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 to obtain the interactive energy coefficient of the second energy interaction path; The third energy interaction path between the reactive subsystems of the grid-type converter, according to the voltage of each grid-type converter corresponding to the third energy interaction path, extract the non-periodic components in the stored energy, dissipated energy and interaction energy of the grid-type converter, so as to obtain the interaction energy coefficient of the third energy interaction path; for the fourth energy interaction path between the active subsystems and reactive subsystems of different grid-type converters, according to the voltage and phase angle of each grid-type converter corresponding to the fourth energy interaction path, extract the non-periodic components in the stored energy, dissipated energy and interaction energy of the grid-type converter, so as to obtain the interaction energy coefficient of the fourth energy interaction path.

[0122] In the specific implementation, regarding the analysis of the single-machine network interaction energy coefficient, the time domain expression of the state variable is substituted into V i_t_pq In the expression, the interaction energy coefficient in the non-periodic component is extracted to obtain the single-machine network interaction energy coefficient λ 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 converteri and ΔV i The response is determined by the following three parameters.

[0125] (1)f p1,i

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

[0127]

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

[0129] From this formula, we can get that f p1,i Always positive value.

[0130] (2)

[0131] The voltage and phase angle oscillation response phase of the grid-connected converter mainly depends on the interaction between the active and reactive control loops. The power flow expression on the transmission line from unit i to Bus A is substituted into the first-order differential equation of the reactive loop to derive the transfer function expression between the voltage and phase angle oscillation components of unit i:

[0132]

[0133] In the formula, f q1,i >0, the power loop control parameter only changes the phase difference, but does not change the range of the phase difference. The interval range is only related to f q2,i 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 positive or negative value of f affects both the amplitude coefficient and the phase coefficient. q2,i It is only related to the converter stable operating point parameters and line structure parameters. Substitute the initial power expression into f q2,i In combination with the line Y-Δ transformation, we can get:

[0136]

[0137] In the formula, It represents the sum of the equivalent conductances of the remaining units interconnected with the i-th unit and the distance from the i-th unit, denoted as g _sum,i .

[0138] It can be seen that f q2,i The positive and negative values ​​mainly depend on the interconnection system structure and conductivity parameters. is the equivalent steady-state conductance g of the i-th unit eq_i , the variation law of the single-machine network interaction energy coefficient is obtained as follows:

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

[0140] When eq_i > _sum,i , that is, f q2,i >0,ω c The term is negative and has a large value, which plays a dominant role. Therefore, λ i_t_pq It presents a negative value as a whole, showing a positive dissipation effect on system oscillation. The power coupling inside the converter shows a positive damping effect on the machine-grid oscillation, which is beneficial to the stability of system oscillation.

[0141] Based on the above analysis, the positive and negative energy coefficients of the single-machine grid interaction are mainly determined by the line structure parameters of the interconnected system. The control parameters only change the size of the interaction, and do not change the positive and negative dissipation properties. Therefore, when laying out multi-grid converters, it is necessary to focus on the access distance and grid structure between the units to ensure that the equivalent steady-state conductance g of the unit is eq_i Greater than the line equivalent conductance parameter g _sum,i , to prevent oscillation and instability problems caused by machine-grid interaction.

[0142] Regarding the analysis of the energy coefficient of the interaction between machines in a multi-grid converter, Δθ i and Δθ j The state variable response is substituted into V ij_t_pp , and solve the non-periodic component to derive the interaction coefficient λ ij_t_pp The expression is:

[0143]

[0144] It can be seen that if the input equivalent reactance between the two converters is much larger than the resistance, Re(Y ij)≈0, at this time, the active interaction coefficient between the machines is close to 0, that is, the power subsystems between the converters are relatively decoupled and will not affect the system stability. However, when the equivalent resistance between the two converters cannot be ignored, Re(Y ij )≠0, there is active interaction between the units, and its positive or negative depends on the steady-state phase angle difference sin(θ i0 -θ j0 ) and the 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 positive or negative can indicate the sending and receiving end positions of the two units. i0 -θ j0 >0, active power flows from unit i to unit j, that is, unit i is at the sending end and unit j is at the receiving end, and vice versa.

[0147] (2)

[0148] is the oscillation phase difference between the phase angles of unit i and unit j, and its value depends on the active power control loop parameters between units. It can be deduced 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 can obtain:

[0151]

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

[0153] Combined with 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 )>0, if D pi >D pj , that is, the active loop bandwidth ω bpi >ω bpj ,but λ ij_t_pp >0, the active interaction between the generators has a negative dissipation effect on the inter-generator oscillation, which is not conducive to system stability. In other words, the faster the active loop response of the sending-end unit is, the more unfavorable it is for the inter-generator oscillation stability. In addition, affected by Re(Y ij), the greater the equivalent conductance between machines, the greater the negative damping effect produced by active interaction.

[0154] Regarding the analysis of the interaction energy between the reactive subsystems of the machines, ΔV i and ΔV j The state variable response is substituted into V ij_t_qq , and solve the non-periodic component to derive the interaction coefficient λ ij_t_qq The expression is:

[0155]

[0156] It can be seen that the reactive subsystem interaction coefficient includes two parts dominated by the equivalent conductance and equivalent susceptance between machines. This paper focuses on the interconnected system under 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 electrical susceptance Im(y ij ) is dominant, and its positive or negative depends on cos(θ i0 -θ j0 )and

[0157] (1)cos(θ i0 -θ j0 )

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

[0159] (2)

[0160] It depends on the difference in the voltage oscillation phase between the i and j ports of the unit. It can be deduced that:

[0161]

[0162] but, The expression is:

[0163]

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

[0165] Because ω bq >0, The closer the reactive power control bandwidth parameter settings of the two units are, The larger the value.

[0166] Combining the above parameters, we can know that the interaction coefficient λ generated by the inter-machine reactive power control subsystem is ij_t_qq It is always a negative value, showing a positive dissipation effect on the system's stored energy accumulation, which is conducive to the rapid convergence of system oscillations. The closer the bandwidth of the reactive power control link between the units, the more positive damping effect the interactive path produces, which improves the stability of the system.

[0167] Regarding the analysis of the interaction energy between the active and reactive subsystems between the generators, the interaction energy between the active and reactive subsystems between the generators is jointly affected by the phase angle of the generator and the voltage state variable. i , Δθ j , ΔV i and ΔV j Substitute the oscillation component into V ij_t_pq , and extracting the non-periodic derivative coefficients, we can get:

[0168]

[0169] It can be seen that λ ij_t_qq There are coefficients dominated by the equivalent conductance and susceptance between machines. c The influence of numerical value, the equivalent susceptance Im(y ij ) is in λ ij_t_qq is dominant, and λ ij_t_qq The positive or negative value of the two units depends mainly on the steady-state phase angle difference sin(θ i0 -θ j0 ), and the phase difference between Δθ and ΔV. Among them, sin(θ i0 -θ j0 ) mainly depends on the location where the unit is connected to the sending and receiving ends. It is mainly affected by the unit control parameters. Further, 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, active or reactive control bandwidth ω bpi >ω bpj ,but λ ij_t_pq >0. The interaction between the active and reactive subsystems between the generators presents a negative dissipation effect on the system, which is not conducive to the convergence of system oscillation. In other words, the faster the active or reactive control loop of the sending-end unit responds, the more unfavorable it is for the stability of the inter-generator oscillation of the system.

[0172] Based on the analysis of the above three types of machine-to-machine interaction paths, the machine-to-machine interaction process mainly exists in the active subsystem interaction and active-reactive subsystem interaction paths, and the damping effect it produces depends on the relative position of the converter access to the sending and receiving ends, and the relative response bandwidth of its power loop. If the power loop response bandwidth of the sending-end unit is greater than that of the receiving-end unit, the active subsystem interaction and active-reactive subsystem interaction processes will both help increase the system disturbance energy and cause the system oscillation to diverge. Although the reactive subsystem interaction process presents a positive dissipation effect, its value is small, and the damping effect on the machine-to-machine oscillation is also small.

[0173] Therefore, this embodiment can provide a multi-grid converter configuration principle for oscillation stability of the interconnected system, as described below:

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

[0175] In this embodiment, in order to solve the problem of oscillation instability in an interconnected system composed of multiple meshed converters, an interaction energy coefficient of an interconnected system is defined by the energy interaction of multiple meshed converters in the power coupling process in the interconnected system. The interaction energy coefficient is used to indicate that the stored energy generated by the power coupling between multiple meshed 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. Therefore, through the interaction energy coefficient, the effect of the energy interaction between multiple meshed converters on slowing down or aggravating the oscillation of the interconnected system can be quantified. At this time, the meshed converters in the interconnected system are in different installation positions, and / or the meshed converters use different control parameters, which are different configuration schemes of multiple meshed converters in the interconnected system. By obtaining the interaction energy coefficients of the interconnected system corresponding to different configuration schemes, the effect of the energy interaction between multiple meshed converters in different configuration schemes on slowing down or aggravating the oscillation of the interconnected system can be determined. Based on this, the optimal configuration of multiple grid-forming converters can be determined, and a configuration scheme that is more effective in mitigating the oscillation of the interconnected system can be obtained, thereby solving the problem of multi-form oscillation instability caused by the connection of large-scale grid-forming converters to the power grid in a low-impedance power grid.

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

[0177] Table 1

[0178]

[0179] In order to verify the influence of the access distance of the grid-connected converter on the oscillation stability of the system, four groups of different line structure parameters are set for simulation verification: g _sum,i =1.04, 1.12, 1.28, 1.43. The simulation curve is as follows Figure 7 shown.

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

[0181] Furthermore, the energy change trajectories of the machine-network interaction in these four scenarios are depicted, such as Figure 4 As shown. Point A→B: The energy of machine-grid interaction shows a rapid downward trend, which is conducive to the rapid consumption of the system's accumulated energy. Point B→C: The energy of machine-grid interaction still shows a spiral downward trend, but the rate of decline is significantly slowed down. Point C→D: The energy of machine-grid interaction rises in a spiral and gradually increases, which helps to increase the system's stored energy. Point D→E: The growth of machine-grid interaction energy is accelerated, and the trend of stored energy divergence is obvious.

[0182] In order to reduce the impact of machine-network interaction on the analysis results, the interconnection system structure parameters are set to meet g _sum,i <g eq,i The scene is set, and the access position of each unit is adjusted so that unit 1 is at the sending end, and units 2 and 3 are both at the receiving end.

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

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

[0185] Figure 5 (b) shows the variation trend of the reactive power subsystem interaction energy coefficient between machines under different reactive power control parameters. As can be seen from the figure, the difference in the reactive power control link parameters between machines does not change λ ij_t_qq The positive and negative properties of the reactive subsystems always show positive dissipation, which is beneficial to the stability of the system. When the reactive control parameters of the two units are closer, λ ij_t_qq The bigger.

[0186] Figure 5 (c) shows the variation trend of the active-reactive subsystem interaction energy coefficient under different active control parameters. When the active control parameter of unit 1 is large and the response speed is fast, λ ij_t_pq will become a positive value, and the interaction between machines is not conducive to the stability of system oscillation. In addition, by comparing the values ​​of the three figures, it can be seen that the interaction between active subsystems and the interaction between active and reactive subsystems play a dominant role and are the key factors affecting the stability of inter-machine oscillation.

[0187] Furthermore, by setting different active control parameters between units, simulation verification is carried out and compared with theoretical results to prove the accuracy of the interaction law between units. Figure 6 shown.

[0188] Figure 6 In (a), when the control parameters of the two units are the same, the interaction between the units is small, and the interaction between the units and the grid is dominant. The structural parameters of the interconnected system do not meet the instability conditions of the machine-grid oscillation. At this time, the system oscillation converges. If the active control parameters of the receiving unit 2 are increased, the interaction between the units will show a positive dissipation effect, so that the system oscillation will further converge to stability. If the active control parameters of the sending unit 1 are increased, the interaction between the units will show a negative dissipation effect, so that the system oscillation changes from convergence to divergence and gradually becomes unstable.

[0189] Figure 6 (b) and Figure 6 (c) is a simulation scenario where the control parameters of the sending and receiving ends are increased. If the active control parameters of the sending unit are continuously increased so that its response rate is greater than that of the receiving unit, the negative dissipation effect of the interaction between the units will gradually intensify, and the system oscillation divergence will become more intense. On the contrary, if the active control parameters of the receiving unit are increased so that it is greater than that of the sending unit, the interaction between the units will show a positive dissipation effect, and the system oscillation will gradually converge to stability.

[0190] To verify the consistency of energy change with simulation, take D p1 =5.4,D p2 =3.6 and D p1 =3.6,D p2 =5.4, these two sets of parameters describe the change trajectory of the interaction energy between each machine as follows Figure 7 and Figure 8 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, the active subsystem interaction and the active-reactive subsystem interaction both show a spiral upward trend, and these two interaction paths both have a negative damping effect on the system oscillation. The reactive subsystem interaction shows a spiral downward change, which is conducive to energy dissipation, but its value is much smaller than that of the other two interaction paths, so the overall interaction energy between machines shows an upward trend.

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

[0193] The step division of the various methods above is only for clear description. When implemented, they can be combined into one step or some steps can be split and decomposed into multiple steps. As long as they include the same logical relationship, they are all within the protection scope of the present invention. Adding insignificant modifications or introducing insignificant designs to the algorithm or process without changing the core design of the algorithm and process are all within the protection scope of the invention.

[0194] Another embodiment of the present invention relates to an optimization configuration device for a multi-network converter. The implementation details of the optimization configuration device for the multi-network converter of this embodiment are specifically described below. The following content is only for the convenience of understanding the implementation details provided, and is not necessary for implementing this solution. The optimization configuration device for the multi-network converter of this embodiment includes:

[0195] A model building module, used for building a mathematical model of an interconnected system according to a power coupling condition between a plurality of meshed converters in the interconnected system composed of the plurality of meshed converters;

[0196] An energy interaction module is used to obtain the energy interaction of multiple grid-connected converters in the interconnected system during the power coupling process according to 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 the energy interaction between multiple grid-connected converters on mitigating or aggravating the oscillation of the interconnected system;

[0198] Among them, the interaction energy coefficient is used to indicate that 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 mesh-type converters based on different installation positions of the mesh-type converters in the interconnected system, and / or different control parameters of the mesh-type converters, and / or different structural parameters of the lines between multiple mesh-type converters, for different configuration schemes of multiple mesh-type converters in the interconnected system by obtaining the interaction energy coefficients of the interconnected system corresponding to different configuration schemes.

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

[0201] It is worth mentioning that all modules involved in this embodiment are logic modules. In practical applications, a logic unit can be a physical unit, a part of a physical unit, or a combination of multiple physical units. In addition, in order to highlight the innovative part of the present invention, this embodiment does not introduce units that are not closely related to solving the technical problem proposed by the present invention, but this does not mean that there are no other units in 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, and the instructions are executed by the at least one processor so that the at least one processor can execute the optimization configuration method of the multi-grid converter in the above-mentioned embodiments.

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

[0204] The processor is responsible for managing the bus and general processing, and can also provide various functions, including timing, peripheral interfaces, voltage regulation, power management, and other control functions. Memory can be used to store data used by the processor when performing operations.

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

[0206] That is, those skilled in the art can understand that all or part of the steps in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a program, and the program is stored in a storage medium, including a number of instructions for a device (which can be a single-chip microcomputer, chip, etc.) or a processor (processor) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (Read-Only Memory, referred to as: ROM), random access memory (Random Access Memory, referred to as: RAM), disk or optical disk and other media that can store program codes.

[0207] Those skilled in the art will appreciate that the above embodiments are specific embodiments for implementing the present invention, and in actual applications, various changes may be made thereto in form and detail without departing from the spirit and scope of the present invention.

Claims

1. A method for optimizing configuration of a multi-network converter, characterized in that: The method comprises: According to the power coupling effect between multiple grid-type converters in the interconnected system composed of multiple grid-type converters, a mathematical model of the interconnected system is constructed; According to 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 storage energy and dissipated energy generated by each grid-type converter independently, as well as the interaction energy generated during power coupling; According to the dissipated energy and interactive energy of each grid-type converter, an interactive energy coefficient is obtained to reflect whether the stored energy of each grid-type converter in the interconnected system is dissipated or accumulated; Based on the fact that the mesh-type converters in the interconnected system are in different installation positions and / or the mesh-type converters use different control parameters, different configuration schemes of multiple mesh-type converters in the interconnected system are provided. By obtaining the interaction energy coefficients of the interconnected system corresponding to different configuration schemes, the optimal configuration of multiple mesh-type converters is determined.

2. The method for optimizing configuration of a multi-network converter according to claim 1, characterized in that: The method of constructing a mathematical model of an interconnected system based on the power coupling effect between multiple meshed converters in an interconnected system composed of multiple meshed converters includes: For each grid-type converter in the interconnected system, an active-phase-angle outer-loop control model and a reactive-voltage outer-loop control model of the grid-type converter are established respectively according to the active-phase-angle outer-loop control module and the reactive-voltage outer-loop control module of the grid-type converter; In combination with the grid-connected structure of multiple grid-type converters, according to the active-phase angle outer loop control model and reactive-voltage outer loop control model of the grid-type converter, 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 respectively obtained; According to the active power and reactive power transmitted by each of the multiple grid-forming converters to the common bus, and the active power and reactive power transmitted by the common bus to the multiple grid-forming converters, a mathematical model of the interconnected system is constructed.

3. The method for optimizing configuration of a multi-network converter according to claim 1, characterized in that: Each of the grid-type converters includes an active subsystem and a reactive subsystem. The network model of the interconnected system for describing the energy interaction process of multiple grid-type converters during power coupling is constructed based on the mathematical model of the interconnected system, including: According to the mathematical model of the interconnected system, an energy interaction process of a first energy interaction path formed by the active subsystem and the reactive subsystem of each grid-type converter, an energy interaction process of a second energy interaction path formed by the active subsystems of different grid-type converters, an energy interaction process of a third energy interaction path formed by the reactive subsystems of different grid-type converters, and an energy interaction process of a fourth energy interaction path formed by the active subsystems and reactive subsystems of different grid-type converters are obtained; A network model of the interconnected system is constructed by combining the energy interaction process of the first energy interaction path, the energy interaction process of the second energy interaction path, the energy interaction process of the third energy interaction path, and the energy interaction process of the fourth energy interaction path.

4. The method for optimizing configuration of a multi-network converter according to claim 3, characterized in that: The step of obtaining, according to the dissipated energy and interactive energy of each grid-type converter, an interactive energy coefficient for reflecting whether the stored energy of each grid-type converter in the interconnected system is dissipated or accumulated comprises: For each grid-type converter in the interconnected system, the non-periodic components of the stored energy, dissipated energy and interactive energy of the grid-type converter are obtained respectively according to the voltage and phase angle of the grid-type converter; According to the dissipated energy of each grid-type converter and the non-periodic component in the interactive energy, an interactive energy coefficient is obtained for reflecting whether the non-periodic component in the stored energy of each grid-type converter in the interconnected system is dissipated or accumulated.

5. The method for optimizing configuration of a multi-network converter according to claim 4, characterized in that: The step of obtaining, according to the dissipated energy of each grid-type converter and the non-periodic component in the interactive energy, an interactive energy coefficient for reflecting whether the non-periodic component in the stored energy of each grid-type converter in the interconnected system is dissipated or accumulated comprises: For a first energy interaction path between an active subsystem and a reactive subsystem of each grid-type converter, extracting a non-periodic component of stored energy, dissipated energy and interaction energy of the grid-type converter according to a voltage and a phase angle of the grid-type converter to obtain an interaction energy coefficient of the first energy interaction path; For the second energy interaction path between the active subsystems of different grid-type converters, according to the phase angle of each grid-type converter corresponding to the second energy interaction path, the non-periodic components in the stored energy, dissipated energy and interaction energy of the grid-type converter are extracted to obtain the interaction energy coefficient of the second energy interaction path; For the third energy interaction path between the reactive subsystems of different grid-type converters, extract the non-periodic components of the stored energy, dissipated energy and interactive energy of the grid-type converter according to the voltage of each grid-type converter corresponding to the third energy interaction path, so as to obtain the interactive energy coefficient of the third energy interaction path; For the fourth energy interaction path between the active subsystems and reactive subsystems of different grid-type converters, the non-periodic components of the stored energy, dissipated energy and interaction energy of the grid-type converter are extracted according to 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.

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

7. The method for optimizing configuration of a multi-network converter according to claim 1, characterized in that: The different configuration schemes of multiple mesh-type converters in the interconnected system are: the mesh-type converters in the interconnected system are at different installation positions, and / or the mesh-type converters use different control parameters, and / or the lines between multiple mesh-type converters use different structural parameters.

8. An optimization configuration device for a multi-network converter, characterized in that: The device comprises: A first model building module is used to build a mathematical model of an interconnected system according to a power coupling effect between multiple grid-forming converters in the interconnected system composed of multiple grid-forming converters; The second model building module is used to build a network model of the interconnected system for describing the energy interaction process of multiple grid-type converters during power coupling according to the mathematical model of the interconnected system; wherein the network model of the interconnected system is used to reflect the storage energy and dissipated energy generated by each grid-type converter independently, as well as the interaction energy generated during power coupling; An energy analysis module is used to obtain an interactive energy coefficient that reflects whether the stored energy of each grid-type converter in the interconnected system is dissipated or accumulated according to the dissipated energy and interactive energy of each grid-type converter; The optimization configuration module is used to determine the optimal configuration of multiple mesh-type converters based on different installation positions of the mesh-type converters in the interconnected system, and / or different control parameters of the mesh-type converters, and / or different structural parameters of the lines between multiple mesh-type converters, for different configuration schemes of multiple mesh-type converters in the interconnected system by obtaining the interaction energy coefficients of the interconnected system corresponding to different configuration schemes.

9. 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, and the instructions are executed by the at least one processor so that the at least one processor can execute the optimization configuration method of the multi-grid converter as described in any one of claims 1 to 7.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the method for optimizing configuration of a multi-grid converter according to any one of claims 1 to 7 is implemented.

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