Parameter setting method and device for wind power plant and computer equipment

Abstract

The invention provides a parameter setting method and device for a wind power plant and computer equipment, and the method comprises the steps: obtaining a full-order linear state space model of the grid-connected double-fed wind power plant based on a state space model of each double-fed fan of the grid-connected double-fed wind power plant; performing dynamic equivalent transformation on the full-order linearization state space model of the grid-connected double-fed wind power plant to obtain a plurality of mutually independent subsystem models of the grid-connected double-fed wind power plant; obtaining a characteristic equation corresponding to the grid-connected double-fed wind power plant based on a plurality of mutually independent subsystem models of the grid-connected double-fed wind power plant; based on the characteristic equation corresponding to the grid-connected doubly-fed wind power plant, the grid-connected doubly-fed wind power plant and preset parameters are set, and a setting result of the preset parameters of the grid-connected doubly-fed wind power plant is obtained. The device is used for executing the method. According to the parameter setting method and device for the wind power plant and the computer equipment provided by the embodiment of the invention, the overall operation and maintenance cost is reduced.

Description

Technical Field

[0001] The present invention relates to the field of new energy technology, and in particular to a method and device for setting parameters of a wind farm, and computer equipment. Background Art

[0002] As global energy demand continues to grow, wind power has been widely used and developed rapidly around the world as an important clean energy. Doubly fed wind turbines have gradually become the mainstream choice for wind farms due to their high efficiency and flexible adjustment capabilities. This type of unit can flexibly adjust the power generation by directly connecting the stator winding to the grid and coordinating the rotor winding with the grid through the inverter.

[0003] In actual operation, doubly-fed wind turbines often face dynamic stability problems caused by various factors, such as system parameters, network topology and control strategy, especially in the design of current control strategy and parameter setting. In the process of grid connection, the converter control strategy and dynamic characteristics of doubly-fed wind turbines play a vital role in system stability, especially under weak connection conditions. This effect is more significant. Usually, in order to simplify the dynamic characteristics of the system in order to analyze the main influencing factors, the dynamic problems caused by the wind power grid-connected system are generally divided into multiple levels such as AC current control time scale, DC voltage control time scale and electromechanical control time scale. Although existing studies have conducted a preliminary analysis of the dynamic characteristics of direct-drive wind turbines at the AC current time scale, in practical applications, the analysis of parameter setting of doubly-fed wind turbines is still relatively scarce. Summary of the invention

[0004] In view of the problems in the prior art, the embodiments of the present invention provide a method, an apparatus and a computer device for setting parameters of a wind farm, which can at least partially solve the problems in the prior art.

[0005] In a first aspect, the present invention provides a method for setting parameters of a wind farm, comprising:

[0006] Based on the state space model of each doubly-fed wind turbine in the grid-connected doubly-fed wind farm, a full-order linearized state space model of the grid-connected doubly-fed wind farm is obtained;

[0007] Performing a dynamic equivalent transformation on the full-order linearized state space model of the grid-connected double-fed wind farm to obtain multiple independent subsystem models of the grid-connected double-fed wind farm;

[0008] Based on a plurality of mutually independent subsystem models of the grid-connected doubly-fed wind farm, obtaining a characteristic equation corresponding to the grid-connected doubly-fed wind farm;

[0009] Based on the characteristic equation corresponding to the grid-connected doubly-fed wind farm, the grid-connected doubly-fed wind farm is adjusted with preset parameters to obtain adjustment results of the preset parameters of the grid-connected doubly-fed wind farm.

[0010] Furthermore, the full-order linearized state space model of the grid-connected doubly-fed wind farm is:

[0011]

[0012] in, is the state variable column vector of the grid-connected double-fed wind farm, ΔX k is the state variable column vector of the kth doubly fed wind turbine, A DFIG is the state space system matrix, A DFIG =diag(A k )+diag(B k )X G diag(C k ), diag(A k )、diag(B k ) and diag(C k ) represent A k , B k and C k (k=1,2,…,N) is a block diagonal matrix with diagonal elements, A k is the system matrix in the full-order state space model of the kth doubly fed wind turbine line, B k is the input matrix in the full-order state space model of the kth DFIG line, C k is the output matrix of the full-order state space model of the k-th doubly fed wind turbine line, X gr is the network reactance matrix of the grid-connected double-fed wind farm, s is the Laplace operator, ω 0 is the power frequency of the grid in steady state, k is a positive integer, and k is greater than or equal to 1 and less than or equal to N, and N is the total number of doubly fed wind turbines in the grid-connected doubly fed wind farm.

[0013] Furthermore, the subsystem model of the grid-connected doubly-fed wind farm is:

[0014]

[0015] Among them, ΔY k is the state quantity of the kth equivalent subsystem, A Yk is the system matrix of the kth equivalent subsystem, E n is the n-order identity matrix; ω 0 is the power frequency of the power grid in steady state; kis the impedance matrix eigenvalue; A c is the state matrix of a single fan; B c is the input matrix of a single fan; C c is the output matrix of a single fan; k=1,2,…,N; N is the number of wind turbines in the wind farm.

[0016] Furthermore, the characteristic equation corresponding to the grid-connected doubly-fed wind farm is:

[0017] a 2 s 2 +a 1 s+a 0 =0

[0018] Among them, a 0 、a 1 and a 2 are the coefficients in the characteristic equation, K ip is the phase-locked loop integral coefficient; V 0 is the steady-state value of the grid-connected point voltage; Q 0 is the steady-state value of reactive power; K p is the phase-locked loop proportional coefficient; ω 0 is the power frequency of the power grid in steady state; P 0 is the steady-state value of active power; X ss is the stator winding self-inductance; η max is the maximum eigenvalue of the impedance matrix of the doubly-fed wind farm.

[0019] Furthermore, the preset parameters include the maximum eigenvalue of the impedance matrix of the doubly-fed wind farm and / or the active power of the doubly-fed wind farm.

[0020] In a second aspect, the present invention provides a parameter setting device for a wind farm, comprising:

[0021] A first acquisition module is used to obtain a full-order linearized state space model of the grid-connected doubly-fed wind farm based on the state space model of each doubly-fed wind turbine in the grid-connected doubly-fed wind farm;

[0022] A transformation module, used for performing a dynamic equivalent transformation on the full-order linearized state space model of the grid-connected double-fed wind farm to obtain multiple independent subsystem models of the grid-connected double-fed wind farm;

[0023] A second obtaining module is used to obtain a characteristic equation corresponding to the grid-connected double-fed wind farm based on a plurality of mutually independent subsystem models of the grid-connected double-fed wind farm;

[0024] The third obtaining module is used to adjust the preset parameters of the grid-connected doubly-fed wind farm based on the characteristic equation corresponding to the grid-connected doubly-fed wind farm, and obtain the adjustment results of the preset parameters of the grid-connected doubly-fed wind farm.

[0025] Furthermore, the full-order linearized state space model of the grid-connected doubly-fed wind farm is:

[0026]

[0027] in, is the state variable column vector of the grid-connected double-fed wind farm, ΔX k is the state variable column vector of the kth doubly fed wind turbine, A DFIG is the state space system matrix, A DFIG =diag(A k )+diag(B k )X G diag(C k ), diag(A k )、diag(B k ) and diag(C k ) represent A k , B k and C k (k=1,2,…,N) is a block diagonal matrix with diagonal elements, A k is the system matrix in the full-order state space model of the kth doubly fed wind turbine line, B k is the input matrix in the full-order state space model of the kth DFIG line, C k is the output matrix of the full-order state space model of the k-th doubly fed wind turbine line, X gr is the network reactance matrix of the grid-connected double-fed wind farm, s is the Laplace operator, ω 0 is the power frequency of the grid in steady state, k is a positive integer, and k is greater than or equal to 1 and less than or equal to N, and N is the total number of doubly fed wind turbines in the grid-connected doubly fed wind farm.

[0028] Furthermore, the subsystem model of the grid-connected doubly-fed wind farm is:

[0029]

[0030] Among them, ΔY k is the state quantity of the kth equivalent subsystem, A Yk is the system matrix of the kth equivalent subsystem, E n is the n-order identity matrix; ω 0 is the power frequency of the power grid in steady state;k is the impedance matrix eigenvalue; A c is the state matrix of a single fan; B c is the input matrix of a single fan; C c is the output matrix of a single fan; k=1,2,…,N; N is the number of wind turbines in the wind farm.

[0031] Furthermore, the characteristic equation corresponding to the grid-connected doubly-fed wind farm is:

[0032] a 2 s 2 +a 1 s+a 0 =0

[0033] Among them, a 0 、a 1 and a 2 are the coefficients in the characteristic equation, K ip is the phase-locked loop integral coefficient; V 0 is the grid connection point voltage; Q 0 is the reactive power; K p is the phase-locked loop proportional coefficient; ω 0 is the power frequency of the power grid in steady state; P 0 is the active power; X ss is the stator winding self-inductance; η max is the maximum eigenvalue of the impedance matrix of the doubly-fed wind farm.

[0034] Furthermore, the preset parameters include the maximum eigenvalue of the impedance matrix of the doubly-fed wind farm and / or the active power of the doubly-fed wind farm.

[0035] In a third aspect, the present invention provides a computer device, comprising a memory, a processor, and a computer program stored in the memory, wherein the processor executes the program to implement the parameter setting method for a wind farm described in any of the above embodiments.

[0036] In a fourth aspect, the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program / instruction, and when the computer program / instruction is executed by a processor, the method for setting parameters of a wind farm described in any of the above embodiments is implemented.

[0037] In a fifth aspect, the present invention provides a computer program product, including a computer program / instruction, which, when executed by a processor, implements the parameter setting method for a wind farm described in any of the above embodiments.

[0038] The wind farm parameter setting method, device and computer equipment provided by the embodiments of the present invention can obtain a full-order linearized state space model of the grid-connected doubly fed wind farm based on the state space model of each doubly fed wind turbine in the grid-connected doubly fed wind farm; perform dynamic equivalent transformation on the full-order linearized state space model of the grid-connected doubly fed wind farm to obtain multiple independent subsystem models of the grid-connected doubly fed wind farm; obtain the characteristic equation corresponding to the grid-connected doubly fed wind farm based on the multiple independent subsystem models of the grid-connected doubly fed wind farm; based on the characteristic equation corresponding to the grid-connected doubly fed wind farm, set the preset parameters of the grid-connected doubly fed wind farm to obtain the setting results of the preset parameters of the grid-connected doubly fed wind farm, which is suitable for the practical application of large-scale doubly fed wind farms, provides an effective solution for the control strategy adjustment in design and actual operation, improves the stability of the system by optimizing the control parameters, and thus reduces the overall operation and maintenance cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0040] Figure 1 It is a flow chart of a method for setting parameters of a wind farm provided in the first embodiment of the present invention.

[0041] Figure 2 It is a schematic diagram of the structure of a grid-connected system of a grid-connected double-fed wind farm provided in the second embodiment of the present invention.

[0042] Figure 3 It is a schematic diagram of the structure of an equivalent subsystem provided by the third embodiment of the present invention.

[0043] Figure 4 It is a schematic diagram of the inner loop control of the rotor-side converter of a doubly-fed wind turbine provided in the fourth embodiment of the present invention.

[0044] Figure 5 It is a schematic diagram of control of a grid-side converter of a doubly-fed wind turbine provided in the fifth embodiment of the present invention.

[0045] Figure 6 Schematic diagram of the relative position between the dq coordinate system and the xy coordinate system provided by the sixth embodiment of the present invention.

[0046] Figure 7 It is a schematic diagram of the working principle of a phase-locked loop provided by the seventh embodiment of the present invention.

[0047] Figure 8It is a schematic diagram of the nonlinear simulation results of the first embodiment provided by the eighth embodiment of the present invention.

[0048] Fig. 9 It is a schematic diagram of the nonlinear simulation results of the second embodiment provided by the ninth embodiment of the present invention.

[0049] Fig.10 It is a schematic structural diagram of a wind farm parameter setting device provided in the tenth embodiment of the present invention.

[0050] Fig.11 It is a schematic diagram of the physical structure of a computer device provided in the eleventh embodiment of the present invention. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the embodiments of the present invention are further described in detail with reference to the accompanying drawings. Here, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention. It should be noted that, in the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other arbitrarily. The acquisition, storage, use, and processing of data in the technical scheme in this application comply with the relevant provisions of laws and regulations. The user information in the embodiments of the present application is obtained through legal and compliant channels, and the acquisition, storage, use, and processing of user information are authorized and agreed by the customer.

[0052] In order to facilitate understanding of the technical solution provided by this application, the relevant contents of the technical solution of this application are first explained below.

[0053] In actual operation, doubly-fed wind turbines often face dynamic stability problems caused by various factors, especially in the design of current control strategies and parameter setting. Through the study of mode analysis, it is found that with the decrease of system connection strength, the small disturbance stability of the wind turbine will be significantly reduced. In the study of the interaction of control links, it is found that when the dynamic characteristics of AC current control and phase-locked loop interact, the instability of the system may be aggravated. Further research reveals through mode analysis and impedance analysis that the stability of doubly-fed wind turbines is closely related to the system configuration, the number of doubly-fed wind turbines and their connection mode with the power grid. Specifically, when the bandwidth of the phase-locked loop is similar to the bandwidth of the AC current control loop, the coupling phenomenon between the two is an important factor that causes the system to be easily unstable. Existing research focuses on the impact of the phase-locked loop model on the stability of doubly-fed wind turbines. Although many literatures have pointed out that the stability of doubly-fed wind power systems is closely related to the dynamic characteristics of the phase-locked loop, a comprehensive understanding of their interaction and stability mechanism under different conditions is still insufficient.

[0054] Most of the existing research is based on the analysis of a few units, and does not fully consider the stability of large-scale wind farm grid-connected systems. Usually, in order to simplify the system dynamic characteristics in order to analyze the main influencing factors, the dynamic problems caused by the wind power grid-connected system are generally divided into multiple levels such as the AC current control time scale, the DC voltage control time scale and the electromechanical control time scale. Since the bandwidth of the inner loop of the current control is usually dozens of times the bandwidth of the outer loop of the power control, the dynamic response speed of the inner loop is much faster than that of the outer loop. Based on this, the stability problem of the inner loop of the current control under the AC current time scale can be discussed separately from the stability problem of the outer loop of the power control under the DC voltage time scale. Therefore, there is an urgent need for a systematic and flexible parameter setting method to ensure the stability of the doubly fed wind farm under different operating conditions.

[0055] Although existing studies have conducted preliminary analysis on the dynamic characteristics of direct-drive wind turbines under the AC current time scale, in practical applications, the reduced-order modeling and analysis methods for doubly-fed wind turbines are still relatively scarce, especially in the dynamic problems of doubly-fed wind turbines connected to the grid. Therefore, it is urgent to provide a comprehensive analysis framework and parameter setting strategy through deeper theoretical discussion and model optimization, so as to effectively ensure the system stability of doubly-fed wind turbines under various working conditions, especially under weak grid connection and heavy load conditions.

[0056] Figure 1 is a flow chart of a method for setting parameters of a wind farm provided by the first embodiment of the present invention, such as Figure 1 As shown, the wind farm parameter setting method provided by the embodiment of the present invention includes:

[0057] S101, based on the state space model of each doubly-fed wind turbine in the grid-connected doubly-fed wind farm, obtaining a full-order linearized state space model of the grid-connected doubly-fed wind farm;

[0058] Specifically, the grid-connected doubly-fed wind farm includes multiple doubly-fed wind turbines, each of which has a corresponding state space model. Based on the state space models of each doubly-fed wind turbine in the grid-connected doubly-fed wind farm, a full-order linearized state space model of the grid-connected doubly-fed wind farm can be obtained.

[0059] For example, Figure 2 As shown, the doubly-fed wind farm includes M branches, each branch includes multiple doubly-fed wind turbines DFIG, and each doubly-fed wind turbine uses a doubly-fed induction generator to generate wind power. The doubly-fed wind farm is connected to the busbar B through M branches, and the external power system is connected to the busbar B through the port A of the doubly-fed wind farm. i represents the number of doubly-fed wind turbines in the i-th branch, i is a natural number, and M represents the total number of branches included in the doubly-fed wind farm.

[0060] exist Figure 2The grid-connected system structure of the grid-connected double-fed wind farm shown in FIG. 1 and the state space model of the kth double-fed wind turbine are expressed as follows:

[0061]

[0062] Among them, X k is the state variable column vector of the kth doubly fed wind turbine, X k =[ΔI nd ΔI nq ΔV dc Δx 1 Δx 2 Δx 3 Δx 4 ] T , where ΔI nd is the d-axis current, ΔI nq is the q-axis current, ΔV dc is the DC voltage, Δx 1 is the d-axis state of the inner ring of the rotor-side converter, Δx 2 is the q-axis state of the inner ring of the rotor-side converter, Δx 3 is the d-axis state of the inner ring of the grid-side converter, Δx 4 A is the q-axis state of the inner ring of the grid-side converter. k is the system matrix in the linearized state space model of the kth doubly fed wind turbine, B k is the input matrix in the linearized state space model of the kth DFIG, C k is the output matrix in the linearized state space model of the kth doubly fed wind turbine, I k =[I kx I ky ] T represents the output current vector of the kth wind turbine grid connection point in the common xy coordinate system, U k =[U kx U ky ] T represents the output current and voltage vector of the grid-connected point of the kth wind turbine in the common xy coordinate system, and Δ represents the increment of the corresponding phasor.

[0063] Assuming that the kth DFIG wind turbine is located on the jth branch of the DFIG wind farm, according to Figure 2 The grid-connected system structure shown in the figure can obtain the voltage equation of the branch where the kth doubly fed wind turbine is located:

[0064]

[0065] Among them, x k is the line impedance of the kth wind turbine, I lkx is the x-axis current of the grid-connected point of the kth wind turbine, I lky is the y-axis current of the kth wind turbine grid connection point, ω0 is the power frequency of the grid in steady state, U k =[U kx U ky ] T is the grid connection point voltage of the kth doubly fed wind turbine.

[0066] By further deducing equation (2), the relationship between voltage and current can be expressed by the Laplace operator and the unit matrix, and we get:

[0067]

[0068] Among them, s is the Laplace operator, E 2 is the identity matrix, I lk is the grid-connected current of the kth wind turbine.

[0069] The network impedance matrix equation of the doubly-fed wind farm can be derived as follows:

[0070] ΔU=X G ΔI (4)

[0071] in, is the voltage column vector of each node in the double-fed wind farm is the current column vector of each node in the doubly fed wind farm, and:

[0072]

[0073] in, is the transformation matrix.

[0074] Therefore, the network reactance matrix of the grid-connected double-fed wind farm can be further defined as follows:

[0075]

[0076] According to equations (1) to (6), the dynamic characteristic model of the grid-connected double-fed wind farm can be obtained as follows:

[0077]

[0078] Formula (7) indicates Figure 2 The full-order linearized state space model of the grid-connected double-fed wind farm is shown in Figure 2. In the model, A DFIG is the state-space system matrix, is the state variable column vector of the grid-connected double-fed wind farm, and A DFIG =diag(A k )+diag(B k )X G diag(C k ), diag(A k ) indicates that Ak is a block diagonal matrix with diagonal elements, diag(B k ) indicates that B k is a block diagonal matrix with diagonal elements, diag(C k ) indicates that C k is a block diagonal matrix (k=1,2,…,N) with diagonal elements.

[0079] S102, performing a dynamic equivalent transformation on the full-order linearized state space model of the grid-connected doubly-fed wind farm to obtain a plurality of mutually independent subsystem models of the grid-connected doubly-fed wind farm;

[0080] Specifically, based on the full-order linearized state-space model of the grid-connected doubly-fed wind farm and ignoring the differences in dynamic characteristics among the doubly-fed wind turbines in the grid-connected doubly-fed wind farm, the full-order linearized state-space model of the grid-connected doubly-fed wind farm is dynamically equivalent to a subsystem model of multiple independent doubly-fed wind turbines.

[0081] By equating the full-order linearized model of the grid-connected doubly-fed wind farm to multiple independent subsystem models, the complex high-order wind farm model is decomposed into multiple low-order subsystem models, and the two keep consistent in dynamic characteristics. This not only simplifies the modeling process of the system, but also significantly reduces the amount of calculation, thereby greatly simplifying the complexity and amount of calculation for the stability analysis of large-scale grid-connected wind farms.

[0082] In the actual operation of wind farms, wind turbines in the same grid-connected system usually use the same model, and their operating parameters and control settings are often very similar. Although the steady-state operating points of each wind turbine may differ to a certain extent due to the uneven distribution of wind speed, such differences usually do not have a significant impact on the linearization model of the system. Therefore, it can be assumed that the dynamic characteristics of all wind turbines are approximately the same. Based on this assumption, it is assumed that the dynamic characteristics of all doubly fed wind turbines in a grid-connected doubly fed wind farm are the same, that is, the differences in the linearization models between doubly fed wind turbine units are not considered. It can be concluded that:

[0083] A k =A c ,B k =B c ,C k =C c ,k=1,2,…,N (8)

[0084] Substituting formula (8) into formula (7), we can obtain:

[0085]

[0086] in, is the second-order identity matrix,

[0087] Let λ k (k=1,2,…,N) is the network reactance matrix X of the grid-connected double-fed wind farm gr eigenvalues, then there exists a matrix Q such that:

[0088]

[0089] In formula (10), diag(λ k ) represents the k (k=1,2,…,N) is a diagonal matrix with principal diagonal elements.

[0090] make

[0091]

[0092] The similarity transformation matrix is ​​defined as:

[0093]

[0094] In formula (12), n is the order of a single doubly fed wind turbine, E n is the n-th order identity matrix.

[0095] From equations (10) to (12), we can obtain:

[0096]

[0097] Make an equivalent transformation ΔX DFIG =Q fc ΔY DFIG , combining equation (7) and equation (8), we can get:

[0098] sΔY DFIG =Q fc -1 diag(A c )Q fc ΔY DFIG +Q fc -1 diag(B c )X G diag(C c )Q fc ΔY DFIG (14)

[0099] From formula (12) and formula (14), we can get:

[0100] Q fc -1 diag(A c )Q fc =diag(A c ) (15)

[0101] From equation (12), equation (13) and equation (14), we can get:

[0102]

[0103] According to formula (15) and formula (16), we have:

[0104] Q fc -1 A c Q fc =A pd (17)

[0105] In formula (17),

[0106] According to formula (17), the matrix A pd With the matrix A DFIG are similar matrices, so their eigenvalues ​​are exactly the same, and the systems described by the two are consistent in dynamic behavior. pd From the expression of , it can be seen that the original grid-connected double-fed wind farm can be equivalent to N independent subsystems, and the two have consistent dynamic characteristics. Assume that the kth equivalent subsystem model of the grid-connected double-fed wind farm can be expressed as:

[0107]

[0108] Among them, ΔY k is the state quantity of the kth equivalent subsystem, A Yk is the system matrix of the kth equivalent subsystem, E n is the n-order identity matrix; ω 0 is the power frequency of the power grid in steady state; k is the impedance matrix eigenvalue; A c is the state matrix of a single fan; B c is the input matrix of a single fan; C c is the output matrix of a single fan; k=1,2,…,N; N is the number of wind turbines in the wind farm.

[0109] For the equivalent subsystem, the established characteristic equation takes into account the influence of the time-scale dynamic characteristics of the AC current, and more intuitively and clearly reveals the influencing factors and mechanisms of the AC current control link on the small disturbance stability of the doubly fed grid-connected system, providing more precise guidance for the optimization of wind farm control parameters.

[0110] Formula (18) describes Figure 1 According to formula (18), the kth equivalent subsystem can be regarded as a doubly fed wind turbine generator set with reactance λk The transmission line is connected to port A, such as Figure 3 shown. Figure 3 Medium: U DFIG is the grid connection point voltage of the doubly fed generator set, I ac is the output current phasor of the doubly-fed generator set, U A is the grid connection point voltage of port A of the doubly fed wind farm.

[0111] S103, obtaining a characteristic equation corresponding to the grid-connected doubly-fed wind farm based on a plurality of mutually independent subsystem models of the grid-connected doubly-fed wind farm;

[0112] Specifically, in the operation of a grid-connected doubly-fed wind farm, AC current control plays a vital role in the dynamic characteristics of the system, directly affecting the stability and overall performance of the wind farm. At the AC current time scale, the dynamic response of the system is closely related to the control strategy. Therefore, the characteristic equation of the equivalent subsystem can be derived by analyzing the key control mechanism of the doubly-fed wind turbine and its network connection characteristics, thereby revealing the dynamic behavior of the wind farm under small disturbance conditions. The characteristic equation corresponding to the grid-connected doubly-fed wind farm can be obtained based on multiple independent subsystem models of the grid-connected doubly-fed wind farm.

[0113] A dynamic model of the doubly fed wind turbine under the AC time scale is established, including the inner loop control of the grid-side converter, the inner loop control of the rotor-side converter, the phase-locked loop and the line model, in order to analyze the stability of the doubly fed wind farm under the AC current time scale.

[0114] The inner loop control of the rotor-side converter of the doubly fed wind turbine is mainly composed of a series of dynamic equations and algebraic equations, which describe the regulation and feedback mechanism of the rotor-side current. The control block diagram is shown in Figure 4 The dynamic equations and algebraic equations of rotor side control are as follows:

[0115]

[0116]

[0117] Where: x 1 and x 2 is an intermediate variable, representing the output of the integral controller of the inner loop control of the rotor side converter; K i_ird and K i_irq I is the integral coefficient of the inner loop control of the machine-side converter; rq is the q-axis current of the rotor-side converter; I rd is the d-axis current of the rotor-side converter; I rqref is the q-axis current reference value of the rotor-side converter; I rdref is the d-axis current reference value of the rotor-side converter; X mis the mutual inductance between the stator and rotor windings; X ss is the stator winding self-inductance; X rr is the rotor winding self-inductance; I sqref is the reference value of the q-axis current in the stator voltage equation; I sdref is the reference value of the d-axis current in the stator voltage equation; V sq is the voltage at the grid point on the q axis; K p_irq and K p_ird is the proportional coefficient of the machine-side converter control link; V rdref is the d-axis component of the rotor-side converter output voltage, V rqref is the q-axis component of the output voltage of the rotor-side converter; the converter adopts an average model, which can be approximately considered as V rdref =V rd , V rqref =V rq .

[0118] The power control of the stator-side converter involves the regulation of active and reactive power, and its expression is:

[0119]

[0120] Among them, P s is the active power output on the stator side; V sd is the stator d-axis voltage; I sd is the d-axis current on the stator side; V sq is the stator q-axis voltage; I sq is the q-axis current on the stator side; Q s Output reactive power for the stator side.

[0121] Grid-side converter control system Figure 5 As shown, the dynamic equation contained in its inner loop control is:

[0122]

[0123] Among them, x 3 and x 4 K is the intermediate state quantity of the inner loop proportional integral link; i_nq and K i_nd K is the integral coefficient of the inner loop control link of the grid-side converter; p_vdc is the proportional coefficient of the DC voltage outer loop control; ΔV vdc =V vdc -V vdcref , V dcref is the reference value of the DC capacitor voltage; I nd is the d-axis current component of the grid-side converter; I nq is the q-axis current component of the grid-side converter.

[0124] The voltage regulation and filter reactance regulation equations of the grid-side converter are as follows:

[0125]

[0126] Among them, V nqref is the q-axis voltage reference value of the grid-side converter; K p_vdc K is the proportional multiple of the DC voltage outer loop proportional integral link; p_nq I is the proportional multiple of the q-axis proportional-integral link of the inner loop controller; nd is the d-axis current component of the grid-side converter; I nq is the q-axis current component of the grid-side converter; V vdc is the DC capacitor voltage; V vdcref is the DC capacitor voltage reference value; K p_nd X is the proportional multiple of the d-axis proportional integral link of the inner loop controller; f Represents filter reactance; V nd is the d-axis component of the grid-connected point voltage; V nq is the q-axis component of the grid-connected point voltage corresponding to the grid-side converter; I nd is the d-axis current component of the grid-side converter; I nq is the q-axis current component of the grid-side converter; V sq is the stator q-axis voltage; V sd is the stator d-axis voltage; V ndref I is the d-axis voltage reference value of the grid-side converter connection point; ndref is the d-axis current reference value of the grid-side converter connection point; ω 0 is the power frequency of the power grid in steady state.

[0127] The power equation of the DC capacitor and the grid-side converter output power are expressed as:

[0128]

[0129] P dc =V nd I nd +V nq I nq (25)

[0130] Where: V dc is the DC bus voltage; C is the DC capacitance; P n is the active power input from the DC side to the grid-side converter, P m is the active power from the machine-side converter to the DC side, P dc It is the active power injected into the DC capacitor by the grid-side converter.

[0131] In order to simplify the analysis model, the above equations (19) to (25) are combined, the dynamic characteristics of the rotor-side and grid-side converter outer rings are ignored, and the state quantities of the rotor-side outer ring and the grid-side outer ring are simplified by making them approach zero, that is: ΔI rqref =ΔI rdref =0, ΔI nqref =ΔI ndref =0, so the simplified AC current time scale transfer function model of the doubly fed wind turbine in the dq coordinate system is obtained as follows:

[0132]

[0133] The phase-locked loop is the core component for synchronization between the doubly-fed wind turbine and the power grid. Figure 6 The mutual transformation between the dq coordinate system and the xy coordinate system shown depends on the normal operation of the phase-locked loop, so its dynamic behavior has an important influence on the stability of the wind farm. Figure 6 Medium θ pll is the phase-locked loop angle, that is, the angle between the dq coordinate system and the xy coordinate system measured by the phase-locked loop; θ xy is the actual angle between the dq coordinate system and the xy coordinate system; U g ∠θ xy =U gx +jU gy Indicates the voltage amplitude U at the grid connection point g With phase angle θ xy , with the grid voltage amplitude component U on the x-axis gx and the amplitude component U of the grid-connected point voltage on the x-axis gy In a doubly-fed wind farm, the dynamics of the phase-locked loop are as follows: Figure 7 As shown, θ xy With θ pll The angle difference and the initial value of the grid voltage amplitude U g0 The result of the multiplication is filtered by a low-pass filter T(s), and the result of the filtering is filtered by a proportional coefficient K p_θ The first result is obtained by amplification processing, and the result of filtering processing is also processed by the integral coefficient K i_θ The second result x is obtained by integrating θ ; The first result and the second result are summed and then integrated to obtain θ pll The equation and the relationship between phase angle and port output can be expressed by the following formula:

[0134]

[0135]

[0136] Among them, θ pll is the phase-locked loop angle; Kp is the phase-locked loop proportional control coefficient; V w0 is the steady-state voltage value of the wind turbine grid connection point; X p is the phase-locked loop state; K ip is the integral control coefficient of the phase-locked loop; V wy0 V is the steady-state value of the voltage on the y-axis at the wind turbine grid connection point; wx0 V is the x-axis steady-state value of the wind turbine grid-connected point voltage; wx V is the x-axis of the wind turbine grid-connected point voltage; wy K is the voltage y-axis of the wind turbine grid connection point; θ for V xy =[ΔV wx ΔV wy ] T .

[0137] Based on the state space form of the simplified model of the double-fed wind turbine in the AC current time scale shown in equation (26), the model of the equivalent grid-connected double-fed wind turbine in the AC current time scale is obtained by combining the xy and dq coordinate system transformation relationships represented in equations (27) to (28):

[0138]

[0139]

[0140] Where: G dq1 -G dq4 is the corresponding element of the transfer function shown in equation (26). pll is the phase angle obtained by the phase-locked loop. V dx0 、V dy0 、V d0 They are the x-axis voltage steady-state value, the y-axis voltage steady-state value, and the voltage amplitude steady-state value. dd0 、V dq0 are the steady-state voltage values ​​of the d-axis and q-axis, respectively. According to the conclusion derived from equation (18), it is believed that a single double-fed wind turbine passes through a section of equivalent reactance η max The transmission line connected to the external power grid constitutes the dynamic equivalent model of the double-fed wind farm. Therefore, the line dynamics is established as:

[0141]

[0142] Combining equation (28) and equation (30), the characteristic equation of the dynamic equivalent reduced-order model of the grid-connected doubly-fed wind farm (i.e., the characteristic equation corresponding to the grid-connected doubly-fed wind farm) is established as follows:

[0143] a 2 s 2 +a 1 s+a 0 =0 (31)

[0144] Among them, a 0 、a 1 and a 2 are the coefficients in the characteristic equation, K ip is the phase-locked loop integral coefficient; V 0 is the steady-state value of the grid-connected point voltage; Q 0 is the steady-state value of reactive power; K p is the phase-locked loop proportional coefficient; ω 0 is the power frequency of the power grid in steady state; P 0 is the steady-state value of active power; X ss is the stator winding self-inductance; η max is the maximum eigenvalue of the impedance matrix of the doubly-fed wind farm. The coefficients in the characteristic equation are related to the converter control parameters, steady-state operating point power and line impedance.

[0145] S104: Based on the characteristic equation and preset parameters corresponding to the grid-connected doubly-fed wind farm, obtain setting results of preset parameters of the grid-connected doubly-fed wind farm.

[0146] Specifically, the Routh-Hurwitz criterion can be used to analyze the characteristic equation corresponding to the grid-connected doubly fed wind farm to obtain the necessary and sufficient conditions for system stability. Under the necessary and sufficient conditions for system stability, the preset parameters in the characteristic equation are used as variables to simplify the characteristic equation corresponding to the grid-connected doubly fed wind farm, so as to obtain the setting results of the preset parameters of the grid-connected doubly fed wind farm. Among them, the preset parameters include but are not limited to active power, the maximum eigenvalue of the impedance matrix of the doubly fed wind farm, and other parameters of the grid-connected doubly fed wind farm, which are selected according to actual needs and are not limited in the embodiments of the present invention. The characteristic equation corresponding to the grid-connected doubly fed wind farm includes the preset parameters of the grid-connected doubly fed wind farm.

[0147] The parameter setting method of a wind farm provided by an embodiment of the present invention can obtain a full-order linearized state-space model of the grid-connected doubly fed wind farm based on the state-space model of each doubly fed wind turbine in the grid-connected doubly fed wind farm; perform dynamic equivalent transformation on the full-order linearized state-space model of the grid-connected doubly fed wind farm to obtain multiple independent subsystem models of the grid-connected doubly fed wind farm; obtain a characteristic equation corresponding to the grid-connected doubly fed wind farm based on the multiple independent subsystem models of the grid-connected doubly fed wind farm; and set the preset parameters of the grid-connected doubly fed wind farm based on the characteristic equation corresponding to the grid-connected doubly fed wind farm to obtain the setting results of the preset parameters of the grid-connected doubly fed wind farm. The method is suitable for the practical application of large-scale doubly fed wind farms, provides an effective solution for the adjustment of control strategies in design and actual operation, improves the stability of the system by optimizing control parameters, and thus reduces the overall operation and maintenance cost.

[0148] On the basis of the above embodiments, further, the full-order linearized state space model of the grid-connected doubly-fed wind farm is:

[0149]

[0150] in, is the state variable column vector of the grid-connected double-fed wind farm, ΔX k is the state variable column vector of the kth doubly fed wind turbine, A DFIG is the state space system matrix, A DFIG =diag(A k )+diag(B k )X G diag(C k ), diag(A k )、diag(B k ) and diag(C k ) represent A k , B k and C k (k=1,2,…,N) is a block diagonal matrix with diagonal elements, A k is the system matrix in the full-order state space model of the kth doubly fed wind turbine line, B k is the input matrix in the full-order state space model of the kth DFIG line, C k is the output matrix of the full-order state space model of the k-th doubly fed wind turbine line, X gr is the network reactance matrix of the grid-connected double-fed wind farm, s is the Laplace operator, ω 0 is the power frequency of the grid in steady state, k is a positive integer, and k is greater than or equal to 1 and less than or equal to N, and N is the total number of doubly fed wind turbines in the grid-connected doubly fed wind farm.

[0151] On the basis of the above embodiments, further, the subsystem model of the grid-connected doubly-fed wind farm is:

[0152]

[0153] Among them, ΔY k is the state quantity of the kth equivalent subsystem, A Yk is the system matrix of the kth equivalent subsystem, E n is the n-order identity matrix; ω 0 is the power frequency of the power grid in steady state; k is the impedance matrix eigenvalue; A c is the state matrix of a single fan; Bc is the input matrix of a single fan; C c is the output matrix of a single fan; k=1,2,…,N; N is the number of wind turbines in the wind farm.

[0154] On the basis of the above embodiments, further, the characteristic equation corresponding to the grid-connected doubly-fed wind farm is:

[0155] a 2 s 2 +a 1 s+a 0 =0

[0156] Among them, a 0 、a 1 and a 2 are the coefficients in the characteristic equation, K ip is the phase-locked loop integral coefficient; V 0 is the steady-state value of the grid-connected point voltage; Q 0 is the steady-state value of reactive power; K p is the phase-locked loop proportional coefficient; ω 0 is the power frequency of the power grid in steady state; P 0 is the steady-state value of active power; X ss is the stator winding self-inductance; η max is the maximum eigenvalue of the impedance matrix of the doubly-fed wind farm.

[0157] On the basis of the above embodiments, further, the preset parameters include the maximum eigenvalue of the impedance matrix of the doubly-fed wind farm and / or the active power of the doubly-fed wind farm.

[0158] For example, the preset parameters include the maximum eigenvalue of the impedance matrix of the doubly-fed wind farm and the active power of the doubly-fed wind farm. The characteristic equation corresponding to the grid-connected doubly-fed wind farm is a 2 s 2 +a 1 s+a 0 =0, according to the Routh-Hurwitz criterion, the necessary and sufficient condition for the stability of the system is: a 2 >0,a 1 >0. Due to a 2 Under normal operating conditions, it is greater than 0, so further, only a is considered 1 >0, the maximum eigenvalue of the impedance matrix of the doubly-fed wind farm and the active power of the doubly-fed wind farm are used as variables to simplify the characteristic equation corresponding to the grid-connected doubly-fed wind farm, and the following two conclusions can be drawn respectively:

[0159]

[0160]

[0161] Among them, ω 0 is the power frequency of the power grid in steady state; V 0 is the steady-state value of bus voltage; K p P is the phase-locked loop proportional coefficient; 0 is the active power; K ip is the phase-locked loop integral coefficient; Q 0 is the reactive power.

[0162] The above equations (32) and (33) are the corresponding η of the double-fed wind farm proposed in the present invention for the system to be stable under the AC current time scale. max and P 0 Parameter setting results. At the same time, the above formula also shows that instability is more likely to occur when the line length is long and the system power is large.

[0163] In order to verify the validity of the theoretical derivation, the embodiment of the present invention takes a grid-connected double-fed wind farm composed of 12 grid-connected double-fed wind turbines as an example to verify the correctness of the results of the grid-connected double-fed wind farm obtained by equations (32) and (33) based on the system small disturbance stability parameter setting under a fast time scale. Each parameter in the embodiment adopts a per-unit value.

[0164] The parameters of the first embodiment are set as follows: the maximum value η of the characteristic value of the wind farm line impedance max is 0.25, the phase-locked loop proportional coefficient K p is 0.55, the integral coefficient K ip is 300, and these parameters are substituted into equation (33) to solve the active power corresponding to critical stability The dominant oscillation modes and their stability criteria corresponding to different active power levels of the wind farm are calculated based on the system linearized state space model and the results are shown in Table 1.

[0165] Table 1 Active power P 0 Stability criterion results when changing

[0166] <![CDATA[P 0 ]]> Judgment results Oscillation mode 0.3 Stablize -2.12±j210.51 0.312 Critical stability -0.11±j252.24 0.33 Unstable 2.65±j250.09

[0167] According to the results in Table 1, if the active power P 0 When it is too large and exceeds the critical stability point obtained by equation (33), the system becomes unstable and the damping of the corresponding oscillation mode becomes negative. On the contrary, by appropriately adjusting the system operating parameters to increase the critical stability point of the system, it is helpful to improve the stability margin of the system. In order to further verify the correctness of the above theoretical derivation and linearization analysis results, a nonlinear simulation of the grid-connected doubly fed wind farm system is carried out. The simulation settings are: at t = 0.3s, the wind speed of doubly fed wind turbines No. 1-3 increases by 5% and recovers at t = 0.35s. The results of nonlinear simulation under different power outputs are shown in Figure 2. Figure 8 As shown in the figure, the vertical axis represents the change based on the steady-state value. Figure 8 It can be seen that with P 0 When it increases to exceed the stable operation boundary, the system gradually tends to become unstable from the initial stable state, which is consistent with the result obtained by the stability criterion proposed in the present invention.

[0168] Similarly, to analyze the maximum value η of the wind farm impedance matrix eigenvalue max The influence of the change on the system stability is set as follows: the output power P of the double-fed wind farm 0 is 0.3, the phase-locked loop parameters are consistent with those of the above embodiment 1, and are substituted into equation (32) to solve The calculation results of the stability criterion for different equivalent impedances are shown in Table 2.

[0169] Table 2 Maximum value η of the anti-matrix eigenvalue max Stability criterion results when changing

[0170] <![CDATA[η max ]]> Judgment results Oscillation mode 0.24 Stablize -4.37±j212.33 0.28 Critical stability -0.15±j203.22 0.31 Unstable 1.58±j202.21

[0171] The nonlinear simulation results under different equivalent impedances are shown in Figure 2. Fig. 9 shown.

[0172] The simulation results show that: (1) If the maximum equivalent impedance of the collector line is too large, that is, the short-circuit ratio of the long-line system of the doubly-fed wind farm is too low, it will also cause the doubly-fed wind turbine to become unstable under the AC current time scale; (2) By adjusting the unit operating parameters of the doubly-fed wind farm, the critical stability point of the system can be changed, that is, the system stability margin can be increased by setting the parameters. (3) The stability criterion and linearization analysis results proposed in this invention are consistent with the conclusions obtained from the time domain simulation.

[0173] Fig.10 is a schematic diagram of the structure of a wind farm parameter setting device provided in the tenth embodiment of the present invention, such as Fig.10 As shown, the parameter setting device for a wind farm provided by an embodiment of the present invention includes a first obtaining module 1001, a transformation module 1002, a second obtaining module 1003 and a third obtaining module 1004, wherein:

[0174] The first acquisition module 1001 is used to obtain the full-order linearized state space model of the grid-connected doubly fed wind farm based on the state space model of each doubly fed wind turbine in the grid-connected doubly fed wind farm; the transformation module 1002 is used to perform dynamic equivalent transformation on the full-order linearized state space model of the grid-connected doubly fed wind farm to obtain multiple independent subsystem models of the grid-connected doubly fed wind farm; the second acquisition module 1003 is used to obtain the characteristic equation corresponding to the grid-connected doubly fed wind farm based on the multiple independent subsystem models of the grid-connected doubly fed wind farm; the third acquisition module 1004 is used to adjust the preset parameters of the grid-connected doubly fed wind farm and the preset parameters based on the characteristic equation corresponding to the grid-connected doubly fed wind farm, and obtain the adjustment results of the preset parameters of the grid-connected doubly fed wind farm.

[0175] Specifically, the grid-connected doubly-fed wind farm includes multiple doubly-fed wind turbines, each of which has a corresponding state space model. The first obtaining module 1001 can obtain the full-order linearized state space model of the grid-connected doubly-fed wind farm based on the state space models of each doubly-fed wind turbine in the grid-connected doubly-fed wind farm.

[0176] Based on the full-order linearized state space model of the grid-connected doubly-fed wind farm, ignoring the dynamic characteristic differences between the various doubly-fed wind turbines in the grid-connected doubly-fed wind farm, the transformation module 1002 dynamically equates the full-order linearized state space model of the grid-connected doubly-fed wind farm to a subsystem model of multiple independent doubly-fed wind turbines.

[0177] In the operation of a grid-connected doubly-fed wind farm, AC current control plays a vital role in the dynamic characteristics of the system, directly affecting the stability and overall performance of the wind farm. At the AC current time scale, the dynamic response of the system is closely related to the control strategy. Therefore, the characteristic equation of the equivalent subsystem can be derived by analyzing the key control mechanism of the doubly-fed wind turbine and its network connection characteristics, thereby revealing the dynamic behavior of the wind farm under small disturbance conditions. The second acquisition module 1003 can obtain the characteristic equation corresponding to the grid-connected doubly-fed wind farm based on multiple independent subsystem models of the grid-connected doubly-fed wind farm.

[0178] The third acquisition module 1004 can use the Routh-Hurwitz criterion to analyze the characteristic equation corresponding to the grid-connected doubly fed wind farm, obtain the necessary and sufficient conditions for system stability, and use the preset parameters in the characteristic equation as variables under the necessary and sufficient conditions for system stability to simplify the characteristic equation corresponding to the grid-connected doubly fed wind farm, so as to obtain the setting results of the preset parameters of the grid-connected doubly fed wind farm. Among them, the preset parameters include but are not limited to the parameters of the grid-connected doubly fed wind farm such as active power and the maximum eigenvalue of the impedance matrix of the doubly fed wind farm, which are selected according to actual needs and are not limited in the embodiment of the present invention. The characteristic equation corresponding to the grid-connected doubly fed wind farm includes the preset parameters of the grid-connected doubly fed wind farm.

[0179] The parameter setting device for a wind farm provided in an embodiment of the present invention can obtain a full-order linearized state-space model of the grid-connected doubly fed wind farm based on the state-space model of each doubly fed wind turbine in the grid-connected doubly fed wind farm; perform dynamic equivalent transformation on the full-order linearized state-space model of the grid-connected doubly fed wind farm to obtain multiple independent subsystem models of the grid-connected doubly fed wind farm; obtain a characteristic equation corresponding to the grid-connected doubly fed wind farm based on the multiple independent subsystem models of the grid-connected doubly fed wind farm; and set the preset parameters of the grid-connected doubly fed wind farm based on the characteristic equation corresponding to the grid-connected doubly fed wind farm to obtain the setting results of the preset parameters of the grid-connected doubly fed wind farm. The device is suitable for the practical application of large-scale doubly fed wind farms, provides an effective solution for the adjustment of control strategies in design and actual operation, improves the stability of the system by optimizing control parameters, and thus reduces the overall operation and maintenance cost.

[0180] On the basis of the above embodiments, further, the full-order linearized state space model of the grid-connected doubly-fed wind farm is:

[0181]

[0182] in, is the state variable column vector of the grid-connected double-fed wind farm, ΔX k is the state variable column vector of the kth doubly fed wind turbine, A DFIG is the state space system matrix, A DFIG =diag(A k )+diag(B k )X G diag(C k ), diag(A k )、diag(B k ) and diag(C k ) represent A k , B k and C k (k=1,2,…,N) is a block diagonal matrix with diagonal elements, A k is the system matrix in the full-order state space model of the kth doubly fed wind turbine line, B k is the input matrix in the full-order state space model of the kth DFIG line, C k is the output matrix of the full-order state space model of the k-th doubly fed wind turbine line, X gr is the network reactance matrix of the grid-connected double-fed wind farm, s is the Laplace operator, ω 0is the power frequency of the grid in steady state, k is a positive integer, and k is greater than or equal to 1 and less than or equal to N, and N is the total number of doubly fed wind turbines in the grid-connected doubly fed wind farm.

[0183] On the basis of the above embodiments, further, the subsystem model of the grid-connected doubly-fed wind farm is:

[0184]

[0185] Among them, ΔY k is the state quantity of the kth equivalent subsystem, A Yk is the system matrix of the kth equivalent subsystem, E n is the n-order identity matrix; ω 0 is the power frequency of the power grid in steady state; k is the impedance matrix eigenvalue; A c is the state matrix of a single fan; B c is the input matrix of a single fan; C c is the output matrix of a single fan; k=1,2,…,N; N is the number of wind turbines in the wind farm.

[0186] On the basis of the above embodiments, further, the characteristic equation corresponding to the grid-connected doubly-fed wind farm is:

[0187] a 2 s 2 +a 1 s+a 0 =0

[0188] Among them, a 0 、a 1 and a 2 are the coefficients in the characteristic equation, K ip is the phase-locked loop integral coefficient; V 0 is the steady-state value of the grid-connected point voltage; Q 0 is the steady-state value of reactive power; K p is the phase-locked loop proportional coefficient; ω 0 is the power frequency of the power grid in steady state; P 0 is the steady-state value of active power; X ss is the stator winding self-inductance; η max is the maximum eigenvalue of the impedance matrix of the doubly-fed wind farm.

[0189] On the basis of the above embodiments, further, the preset parameters include the maximum eigenvalue of the impedance matrix of the doubly-fed wind farm and / or the active power of the doubly-fed wind farm.

[0190] The embodiments of the apparatus provided in the embodiments of the present invention can be specifically used to execute the processing flow of the above-mentioned method embodiments, and its functions are not described in detail here, and reference can be made to the detailed description of the above-mentioned method embodiments.

[0191] Fig.11 is a schematic diagram of the physical structure of a computer device provided by an embodiment of the present invention, such as Fig.11 As shown, the computer device may include: a processor (processor) 1101, a communication interface (Communications Interface) 1102, a memory (memory) 1103 and a communication bus 1104, wherein the processor 1101, the communication interface 1102, and the memory 1103 communicate with each other through the communication bus 1104. The processor 1101 can call the logic instructions in the memory 1103 to execute the following method: based on the state space model of each doubly fed wind turbine in the grid-connected doubly fed wind farm, obtain the full-order linearized state space model of the grid-connected doubly fed wind farm; perform dynamic equivalent transformation on the full-order linearized state space model of the grid-connected doubly fed wind farm to obtain multiple independent subsystem models of the grid-connected doubly fed wind farm; based on the multiple independent subsystem models of the grid-connected doubly fed wind farm, obtain the characteristic equation corresponding to the grid-connected doubly fed wind farm; based on the characteristic equation corresponding to the grid-connected doubly fed wind farm, adjust the preset parameters of the grid-connected doubly fed wind farm and obtain the adjustment results of the preset parameters of the grid-connected doubly fed wind farm.

[0192] In addition, the logic instructions in the above-mentioned memory 1103 can be implemented in the form of software functional units and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0193] The present embodiment discloses a computer program product, which includes a computer program stored on a non-transitory computer-readable storage medium, and the computer program includes program instructions. When the program instructions are executed by a computer, the computer can execute the methods provided by the above-mentioned method embodiments, for example, including: based on the state space model of each doubly fed wind turbine in the grid-connected doubly fed wind farm, obtaining a full-order linearized state space model of the grid-connected doubly fed wind farm; performing a dynamic equivalent transformation on the full-order linearized state space model of the grid-connected doubly fed wind farm to obtain multiple independent subsystem models of the grid-connected doubly fed wind farm; based on the multiple independent subsystem models of the grid-connected doubly fed wind farm, obtaining a characteristic equation corresponding to the grid-connected doubly fed wind farm; based on the characteristic equation corresponding to the grid-connected doubly fed wind farm, adjusting the preset parameters of the grid-connected doubly fed wind farm and obtaining the adjustment results of the preset parameters of the grid-connected doubly fed wind farm.

[0194] The present embodiment provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program / instruction, wherein the computer program / instruction enables the computer to execute the methods provided by the above-mentioned method embodiments, for example, including: obtaining a full-order linearized state-space model of the grid-connected doubly-fed wind farm based on the state-space model of each doubly-fed wind turbine in the grid-connected doubly-fed wind farm; performing a dynamic equivalent transformation on the full-order linearized state-space model of the grid-connected doubly-fed wind farm to obtain a plurality of mutually independent subsystem models of the grid-connected doubly-fed wind farm; obtaining a characteristic equation corresponding to the grid-connected doubly-fed wind farm based on the plurality of mutually independent subsystem models of the grid-connected doubly-fed wind farm; and adjusting the preset parameters of the grid-connected doubly-fed wind farm based on the characteristic equation corresponding to the grid-connected doubly-fed wind farm and obtaining the adjustment results of the preset parameters of the grid-connected doubly-fed wind farm.

[0195] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0196] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0197] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0198] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0199] In the description of this specification, the description with reference to the terms "one embodiment", "a specific embodiment", "some embodiments", "for example", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0200] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for setting parameters of a wind farm, characterized in that: include: Based on the state space model of each doubly-fed wind turbine in the grid-connected doubly-fed wind farm, a full-order linearized state space model of the grid-connected doubly-fed wind farm is obtained; Performing a dynamic equivalent transformation on the full-order linearized state space model of the grid-connected double-fed wind farm to obtain multiple independent subsystem models of the grid-connected double-fed wind farm; Based on a plurality of mutually independent subsystem models of the grid-connected doubly-fed wind farm, obtaining a characteristic equation corresponding to the grid-connected doubly-fed wind farm; Based on the characteristic equation corresponding to the grid-connected double-fed wind farm, preset parameters of the grid-connected double-fed wind farm are adjusted to obtain adjustment results of the preset parameters of the grid-connected double-fed wind farm.

2. The method according to claim 1, characterized in that: The full-order linearized state space model of the grid-connected doubly-fed wind farm is: in, is the state variable column vector of the grid-connected double-fed wind farm, ΔX k is the state variable column vector of the kth doubly fed wind turbine, A DFIG is the state space system matrix, A DFIG =diag(A k )+diag(B k )X G diag(C k ), diag(A k )、diag(B k ) and diag(C k ) represent A k , B k and C k (k=1,2,…,N) is a block diagonal matrix with diagonal elements, A k is the system matrix in the full-order state space model of the kth doubly fed wind turbine line, B k is the input matrix in the full-order state space model of the kth DFIG line, C k is the output matrix of the full-order state space model of the k-th doubly fed wind turbine line, X gr is the network reactance matrix of the grid-connected double-fed wind farm, s is the Laplace operator, ω0 is the power frequency of the power grid in steady state, k is a positive integer, and k is greater than or equal to 1 and less than or equal to N, and N is the total number of doubly fed wind turbines in the grid-connected doubly fed wind farm.

3. The method according to claim 1, characterized in that The subsystem model of the grid-connected double-fed wind farm is: Among them, ΔY k is the state quantity of the kth equivalent subsystem, A Yk is the system matrix of the kth equivalent subsystem, E n is the n-order unit matrix; ω0 is the power frequency of the power grid in steady state; λ k is the impedance matrix eigenvalue; A c is the state matrix of a single fan; B c is the input matrix of a single fan; C c is the output matrix of a single fan; k=1,2,…,N; N is the number of wind turbines in the wind farm.

4. The method according to claim 1, characterized in that The characteristic equation corresponding to the grid-connected doubly-fed wind farm is: a2s 2 +a1s+a0=0 Among them, a0, a1 and a2 are the coefficients in the characteristic equation, K ip is the integral coefficient of the phase-locked loop; V0 is the steady-state value of the grid-connected point voltage; Q0 is the steady-state value of reactive power; K p is the phase-locked loop proportional coefficient; ω0 is the power frequency of the grid under steady-state conditions; P0 is the steady-state value of active power; X ss is the stator winding self-inductance; η max is the maximum eigenvalue of the impedance matrix of the doubly-fed wind farm.

5. The method according to any one of claims 1 to 4, characterized in that: The preset parameters include the maximum eigenvalue of the impedance matrix of the doubly-fed wind farm and / or the active power of the doubly-fed wind farm.

6. A parameter setting device for a wind farm, characterized in that: include: A first acquisition module is used to obtain a full-order linearized state space model of the grid-connected doubly-fed wind farm based on the state space model of each doubly-fed wind turbine in the grid-connected doubly-fed wind farm; A transformation module, used for performing a dynamic equivalent transformation on the full-order linearized state space model of the grid-connected double-fed wind farm to obtain multiple independent subsystem models of the grid-connected double-fed wind farm; A second obtaining module is used to obtain a characteristic equation corresponding to the grid-connected double-fed wind farm based on a plurality of mutually independent subsystem models of the grid-connected double-fed wind farm; The third obtaining module is used to adjust the preset parameters of the grid-connected doubly-fed wind farm based on the characteristic equation corresponding to the grid-connected doubly-fed wind farm, and obtain the adjustment results of the preset parameters of the grid-connected doubly-fed wind farm.

7. The device according to claim 6, characterized in that The full-order linearized state space model of the grid-connected doubly-fed wind farm is: in, is the state variable column vector of the grid-connected double-fed wind farm, ΔX k is the state variable column vector of the kth doubly fed wind turbine, A DFIG is the state space system matrix, A DFIG =diag(A k )+diag(B k )X G diag(C k ), diag(A k )、diag(B k ) and diag(C k ) represent A k , B k and C k (k=1,2,…,N) is a block diagonal matrix with diagonal elements, A k is the system matrix in the full-order state space model of the kth doubly fed wind turbine line, B k is the input matrix in the full-order state space model of the kth DFIG line, C k is the output matrix of the full-order state space model of the k-th doubly fed wind turbine line, X gr is the network reactance matrix of the grid-connected double-fed wind farm, s is the Laplace operator, ω0 is the power frequency of the power grid in steady state, k is a positive integer, and k is greater than or equal to 1 and less than or equal to N, and N is the total number of doubly fed wind turbines in the grid-connected doubly fed wind farm.

8. The device according to claim 6, characterized in that The subsystem model of the grid-connected double-fed wind farm is: Among them, ΔY k is the state quantity of the kth equivalent subsystem, A Yk is the system matrix of the kth equivalent subsystem, E n is the n-order unit matrix; ω0 is the power frequency of the power grid in steady state; λ k is the impedance matrix eigenvalue; A c is the state matrix of a single fan; B c is the input matrix of a single fan; C c is the output matrix of a single fan; k=1,2,…,N; N is the number of wind turbines in the wind farm.

9. The device according to claim 6, characterized in that The characteristic equation corresponding to the grid-connected doubly-fed wind farm is: a2s 2 +a1s+a0=0 Among them, a0, a1 and a2 are the coefficients in the characteristic equation, K ip is the phase-locked loop integral coefficient; V0 is the grid-connected point voltage; Q0 is the reactive power; K p is the proportional coefficient of the phase-locked loop; ω0 is the power frequency of the power grid under steady-state conditions; P0 is the active power; X ss is the stator winding self-inductance; η max is the maximum eigenvalue of the impedance matrix of the doubly-fed wind farm.

10. The device according to any one of claims 6 to 9, characterized in that The preset parameters include the maximum eigenvalue of the impedance matrix of the doubly-fed wind farm and / or the active power of the doubly-fed wind farm.

11. A computer device comprising a memory, a processor and a computer program stored in the memory, characterized in that: The processor executes the computer program to implement the steps of the method according to any one of claims 1 to 5.

12. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program / instruction, which implements the steps of the method according to any one of claims 1 to 5 when executed by a processor.

13. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instructions are executed by a processor, the steps of the method according to any one of claims 1 to 5 are implemented.

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