Wind turbine generator impedance characteristic parameter sensitivity analysis method and system

Abstract

The invention discloses a wind turbine generator impedance characteristic parameter sensitivity analysis method and system, and relates to the technical field of new energy power generation system stability analysis and control, and the method comprises the steps: building a wind power plant grid-connected system impedance model based on a DQ coordinate system; calculating the impedance sensitivity of the wind power plant grid-connected system according to the DQ impedance of the wind power plant grid-connected system; and according to an impedance sensitivity analysis result, obtaining a parameter with the maximum influence on the impedance of the wind power plant grid-connected system. According to the method, by calculating and analyzing the impedance sensitivity, the influence degree of each parameter on the impedance characteristic of the wind power plant can be quantified, and key parameters causing instability of the system can be optimized and adjusted in a targeted manner; compared with a traditional characteristic value analysis method, impedance analysis does not need to depend on the internal structure and parameters of the wind turbine generator, only the impedance model needs to be obtained through measurement, the analysis process is simplified, and the analysis efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of stability analysis and control of new energy power generation systems, and in particular to a method and system for analyzing the sensitivity of impedance characteristic parameters of a wind turbine generator set. Background Art

[0002] The grid-connected new energy uses power electronic equipment to realize electric energy conversion and transmission. The multi-time scale control characteristics of power electronic equipment have a profound impact on the wide-band frequency domain characteristics of the new energy power generation system, resulting in wide-band oscillation phenomenon in wind power, photovoltaic and other new energy grid-connected systems. The nonlinear strong coupling control characteristics of power electronic equipment further make the wide-band oscillation phenomenon have complex oscillation characteristics of oscillation frequency coupling.

[0003] In the analysis of oscillation mechanism, there are mainly eigenvalue analysis method and impedance analysis method. The advantage of impedance analysis method is that the impedance model of the asynchronous machine power supply can be obtained by measurement without relying on the internal structure and parameters of the asynchronous machine power supply.

[0004] Large-scale renewable energy stations are composed of a large number of renewable energy units connected by cables or submarine cables. The electrical topology within the renewable energy station has a great influence on the impedance characteristics of the station. At the same time, the topology within the station may also change with the change of operating mode. In practical applications, it is necessary to consider the actual topology of the renewable energy station and the impact of its changes. Summary of the invention

[0005] In view of the above-mentioned problems, the present invention is proposed.

[0006] Therefore, the technical problem solved by the present invention is: the prior art lacks an analysis method for the actual topology of large-scale new energy stations and the degree of influence of grid-connected oscillation caused by topology changes within the field, and how to solve the problem of evaluating the impact of parameter changes on system stability through impedance sensitivity.

[0007] To solve the above technical problems, the present invention provides the following technical solutions: a method for analyzing the sensitivity of wind turbine impedance characteristic parameters, comprising constructing an impedance model of a wind farm grid-connected system based on a DQ coordinate system; calculating the impedance sensitivity of the wind farm grid-connected system according to the DQ impedance of the wind farm grid-connected system; and obtaining the parameter with the greatest impact on the impedance of the wind farm grid-connected system according to the impedance sensitivity analysis result.

[0008] As a preferred solution of the wind turbine impedance characteristic parameter sensitivity analysis method described in the present invention, the DQ coordinate system includes a main circuit coordinate system and a control system coordinate system.

[0009] As a preferred solution of the wind turbine impedance characteristic parameter sensitivity analysis method of the present invention, wherein: the main circuit coordinate system and the control system coordinate system include: the main circuit coordinate system is (dmf ,q mf ), rotates with the fundamental frequency ω0 as the angular velocity, and uses the PCC bus voltage for orientation; the coordinate system of the direct-drive wind turbine grid-side converter control system is (d cf ,q cf ), with the phase-locked loop angular frequency ω pll The angular velocity rotation is carried out by using the voltage at the fan outlet for orientation. The conversion relationship between the variable x in the main circuit coordinate system and the control system coordinate system is expressed as:

[0010]

[0011] Among them, θ pll Represents the angle between the main circuit coordinate system and the control system coordinate system.

[0012] As a preferred solution of the wind turbine impedance characteristic parameter sensitivity analysis method described in the present invention, the wind farm grid-connected system impedance model includes a wind farm impedance model and an AC system impedance model; the wind farm grid-connected system includes separating the system at the PCC port, selecting the PCC bus voltage As the input variable, the 33kV incoming line current of the wind farm is selected As the output variable, the wind farm impedance model Z is obtained WF And the AC system impedance model Z AC .

[0013] As a preferred solution of the wind turbine impedance characteristic parameter sensitivity analysis method of the present invention, the wind farm grid-connected system DQ impedance includes the wind farm system DQ impedance obtained according to the wind farm system frequency domain model, expressed as:

[0014]

[0015] Among them, s′ represents a complex variable, A WF represents the state matrix, B WF represents the input matrix, C WF represents the output matrix, D WF represents the feedforward matrix, I represents the identity matrix, ΔU WF represents a small perturbation of the input variable, Y WF Represents a small perturbation of the output variable.

[0016] As a preferred solution of the wind turbine impedance characteristic parameter sensitivity analysis method described in the present invention, wherein: the wind farm frequency domain model includes obtaining a wind farm system state space equation and an output equation according to a state space model of the wind farm system, linearizing the obtained equation at a steady-state operation point to obtain a wind farm frequency domain model;

[0017] The state space model of the wind farm system is expressed as:

[0018]

[0019] Among them, X represents the state variable, U represents the input variable, and d represents the differential. represents the differential with respect to time;

[0020] Define the wind farm input variables, expressed as:

[0021]

[0022] in, Indicates the voltage at the wind farm grid connection point, represents the d-axis component of the voltage at the wind farm connection point, represents the q-axis component of the voltage at the wind farm grid connection point, and T represents the transpose of the matrix;

[0023] Define the wind farm output variables, expressed as:

[0024]

[0025] in, represents the output current of the wind farm, represents the d-axis component of the wind farm output current, The q-axis component of the wind farm output current;

[0026] According to the definition, the state space equation and output equation of the wind farm system are established and expressed as:

[0027]

[0028] in, represents the time derivative of the wind farm state variable;

[0029] The state space equation and output equation of the wind farm system are linearized at the steady-state operation point to obtain the frequency domain model of the wind farm system, which is expressed as:

[0030]

[0031] Where ΔX WF represents a small perturbation of the state variable, ΔU WF represents a small perturbation of the input variable, ΔY WF Represents a small perturbation of the output variable.

[0032] As a preferred solution of the wind turbine impedance characteristic parameter sensitivity analysis method of the present invention, wherein: the impedance sensitivity includes transfer function sensitivity, real part sensitivity and imaginary part sensitivity;

[0033] Transfer function sensitivity, expressed as:

[0034]

[0035] Among them, k represents the parameter for sensitivity analysis, s represents the Laplace operator; the real part sensitivity is expressed as:

[0036] H kRe (k,s)=Re{H k (k,s)}

[0037] Imaginary sensitivity, expressed as:

[0038] H kIm (k,s)=Im{H k (k,s)}

[0039] The absolute value of impedance sensitivity determines the magnitude of the effect of parameter changes on system impedance; the positive or negative value of the sensitivity determines the direction in which the real and imaginary parts of the system impedance change with the parameters; from the definition of impedance sensitivity, Z WF(s′) The sensitivity to parameter α is expressed as:

[0040]

[0041] Among them, Z all represents the total impedance, The wind farm impedance Z WF(s′) Sensitivity of the real part to the parameter α, The wind farm impedance Z WF(s′) The sensitivity of the imaginary part to the parameter α, j represents an imaginary number.

[0042] Another object of the present invention is to provide a wind turbine impedance characteristic parameter sensitivity analysis system, which can analyze the parameters of the grid-connected system that have the greatest impact on impedance through impedance sensitivity, providing technical support for optimizing the stability and reliability of the wind farm grid-connected system.

[0043] As a preferred solution of the wind turbine impedance characteristic parameter sensitivity analysis system described in the present invention, it includes: a construction module, a calculation module, and an identification module; the construction module is used to construct an impedance model of a wind farm grid-connected system based on a DQ coordinate system; the calculation module is used to calculate the impedance sensitivity of the wind farm grid-connected system according to the DQ impedance of the wind farm grid-connected system; the identification module is used to identify the parameter with the greatest impact on the impedance of the grid-connected system according to the impedance sensitivity analysis result.

[0044] A computer device comprises a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement a step of a method for analyzing the sensitivity of impedance characteristic parameters of a wind turbine generator set.

[0045] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of a method for analyzing the sensitivity of wind turbine impedance characteristic parameters.

[0046] Beneficial effects of the present invention: The wind turbine impedance characteristic parameter sensitivity analysis method provided by the present invention can quantify the influence of various parameters on the impedance characteristics of the wind farm by calculating and analyzing the impedance sensitivity, and can optimize and adjust the key parameters that cause system instability in a targeted manner; compared with the traditional eigenvalue analysis method, impedance analysis does not need to rely on the internal structure and parameters of the wind turbine, and only needs to obtain the impedance model through measurement, which simplifies the analysis process and improves the analysis efficiency; at the same time, the analysis method of the present invention is not only applicable to wind turbines, but can also be applied to other new energy systems such as photovoltaic power generation and energy storage systems, and has broad application prospects; the present invention has achieved good results in impedance sensitivity analysis and analysis of the causes of oscillation of new energy grid-connected systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0048] Figure 1 An overall flow chart of a method for analyzing the sensitivity of wind turbine impedance characteristic parameters provided by the first embodiment of the present invention.

[0049] Figure 2 A relative position diagram of a main circuit coordinate system and a phase-locked loop coordinate system of a method for analyzing the sensitivity of wind turbine impedance characteristic parameters provided by the first embodiment of the present invention.

[0050] Figure 3 A schematic diagram of establishing a wind farm grid-connected impedance model for a method for analyzing wind turbine impedance characteristic parameters sensitivity provided by the first embodiment of the present invention.

[0051] Figure 4 A DQ impedance equivalent circuit diagram of a wind farm grid-connected system of a wind turbine generator impedance characteristic parameter sensitivity analysis method provided by the first embodiment of the present invention.

[0052] Figure 5 A topological structure diagram of a direct-drive wind farm according to a method for analyzing the sensitivity of wind turbine impedance characteristic parameters provided by the second embodiment of the present invention.

[0053] Figure 6A cable line topology diagram of a wind turbine impedance characteristic parameter sensitivity analysis method provided in a second embodiment of the present invention.

[0054] Figure 7 The impedance sensitivity diagram of each parameter of a wind turbine impedance characteristic parameter sensitivity analysis method provided by the second embodiment of the present invention.

[0055] Figure 8 This is an overall flow chart of a wind turbine impedance characteristic parameter sensitivity analysis system provided in the third embodiment of the present invention. DETAILED DESCRIPTION

[0056] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0057] Example 1, reference Figure 1-Figure 4 , which is an embodiment of the present invention, provides a method for analyzing the sensitivity of wind turbine impedance characteristic parameters, comprising:

[0058] S1: Based on the DQ coordinate system, the wind farm grid-connected system impedance model is constructed.

[0059] Furthermore, the DQ coordinate system includes a main circuit coordinate system and a control system coordinate system.

[0060] It should be noted that the main circuit coordinate system and the control system coordinate system include, for example Figure 2 The figure shows the relative position of the main circuit coordinate system and the phase-locked loop coordinate system. The main circuit coordinate system is (d mf ,q mf ), rotates with the fundamental frequency ω0 as the angular velocity, and uses the PCC bus voltage for orientation; the coordinate system of the direct-drive wind turbine grid-side converter control system is (d cf ,q cf ), with the phase-locked loop angular frequency ω pll The angular velocity rotation is carried out by using the voltage at the fan outlet for orientation. The conversion relationship between the variable x in the main circuit coordinate system and the control system coordinate system is expressed as:

[0061]

[0062] Among them, θ pll Represents the angle between the main circuit coordinate system and the control system coordinate system.

[0063] It should also be noted that the wind farm grid-connected system impedance model includes the wind farm impedance model and the AC system impedance model; Figure 3 The figure shows the schematic diagram of the AC grid-connected system of a wind farm. The system is separated at the PCC port and the PCC bus voltage is selected. As the input variable, the 33kV incoming line current of the wind farm is selected As the output variable, the wind farm impedance model Z is obtained WF And the AC system impedance model Z AC .

[0064] It should also be noted that the wind farm grid-connected system can be equivalent to Figure 4 The impedance equivalent circuit diagram shown in the figure shows that the impedance equivalent circuit system is divided into two subsystems at the PCC port: the AC power grid and the wind farm converter station. The AC power grid can be equivalent to an ideal voltage source and an impedance Z AC(s) When the wind speed is determined, the output power of the wind farm is constant, which can be equivalent to an ideal current source and admittance Y WF(s) The AC grid and the wind farm are connected in parallel through the PCC bus voltage Wind farm 33kV incoming line current Connect interfaces.

[0065] It should also be noted that the established grid-connected impedance model does not require the understanding of the internal structure and parameters of the wind turbine generator system. The impedance model can be obtained through measurement, which is suitable for large-scale renewable energy sites. It can provide a basis for analyzing the grid-connected interaction of wind farms and reveal the coupling relationship between wind farms and the power grid.

[0066] S2: Calculate the impedance sensitivity of the wind farm grid-connected system based on the DQ impedance of the wind farm grid-connected system.

[0067] Furthermore, the DQ impedance of the wind farm grid-connected system includes the DQ impedance of the wind farm system obtained according to the frequency domain model of the wind farm system, which is expressed as:

[0068]

[0069] Among them, s′ represents a complex variable, A WF represents the state matrix, B WF represents the input matrix, C WF represents the output matrix, D WF represents the feedforward matrix, I represents the identity matrix, ΔU WF represents a small perturbation of the input variable, Y WF Represents a small perturbation of the output variable.

[0070] It should be noted that the frequency domain model of the wind farm includes obtaining the state space equation and output equation of the wind farm system according to the state space model of the wind farm system, linearizing the obtained equation at the steady-state operation point to obtain the frequency domain model of the wind farm; the state space model of the wind farm system is expressed as:

[0071]

[0072] Among them, X represents the state variable, U represents the input variable, and d represents the differential. Represents the differential with respect to time.

[0073] It should also be noted that the wind farm input variables are defined as:

[0074]

[0075] in, Indicates the voltage at the wind farm grid connection point, represents the d-axis component of the voltage at the wind farm connection point, represents the q-axis component of the voltage at the wind farm grid connection point, and T represents the transpose of the matrix; the wind farm output variable is defined as:

[0076]

[0077] in, represents the output current of the wind farm, represents the d-axis component of the wind farm output current, The q-axis component of the wind farm output current; according to the definition, the wind farm system state space equation and output equation are established, which are expressed as:

[0078]

[0079] in, represents the time derivative of the wind farm state variable; linearize the wind farm system state space equation and output equation at the steady-state operation point to obtain the wind farm system frequency domain model, which is expressed as:

[0080]

[0081] Where ΔX WF represents a small perturbation of the state variable, ΔU WF represents a small perturbation of the input variable, ΔY WF Represents a small perturbation of the output variable.

[0082] It should also be noted that impedance sensitivity is an important parameter for evaluating the degree and direction of the influence of parameter changes on system impedance, which reveals the impact of evaluation parameters on system stability.

[0083] S3: Based on the impedance sensitivity analysis results, the parameters with the greatest impact on the wind farm grid-connected system impedance are obtained.

[0084] Furthermore, impedance sensitivity includes transfer function sensitivity, real part sensitivity, and imaginary part sensitivity.

[0085] It should be noted that the transfer function sensitivity describes the sensitivity of the system transfer function to parameter changes, and the transfer function sensitivity can reveal the dynamic characteristics of the system at different frequencies; the real part sensitivity describes the sensitivity of the real part of the system impedance to parameter changes, and the real part sensitivity can reveal the sensitivity of the system impedance to frequency changes; the imaginary part sensitivity describes the sensitivity of the imaginary part of the system impedance to parameter changes, and the imaginary part sensitivity can reveal the sensitivity of the system impedance to phase changes.

[0086] It should also be noted that the transfer function sensitivity is expressed as:

[0087]

[0088] Among them, k represents the parameter for sensitivity analysis, s represents the Laplace operator; the real part sensitivity is expressed as:

[0089] H kRe (k,s)=Re{H k (k,s)}

[0090] Imaginary sensitivity, expressed as:

[0091] H kIm (k,s)=Im{H k (k,s)}.

[0092] It should also be noted that the absolute value of impedance sensitivity determines the magnitude of the effect of parameter changes on system impedance; the positive or negative value of the sensitivity determines the direction in which the real and imaginary parts of the system impedance change with the parameters; from the definition of impedance sensitivity, we know that Z WF(s′) The sensitivity to parameter α is expressed as:

[0093]

[0094] Among them, Z all represents the total impedance, The wind farm impedance Z WF(s′) Sensitivity of the real part to the parameter α, The wind farm impedance Z WF(s′) The sensitivity of the imaginary part to the parameter α, j represents an imaginary number.

[0095] It should also be noted that the analysis of the impact of different parameters on impedance is to analyze different types of parameters, such as control parameters, structural parameters, etc. Comprehensively evaluating the impact of parameters on the system can provide parameters for wind turbine design and operation and improve system performance and reliability.

[0096] Example 2, reference Figure 5-Figure 7 , which is an embodiment of the present invention, provides a method for analyzing the sensitivity of wind turbine impedance characteristic parameters. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through economic benefit calculation and simulation experiments.

[0097] First, if Figure 5 As shown, this embodiment establishes a permanent magnet direct-drive wind farm state space model consisting of 4 links and 16 5MW direct-drive wind turbines. Each wind turbine is connected to other wind turbines through a 33kV cable and finally gathered to a common connection point (PCC), and then stepped up to 220kV through a wind farm outlet transformer and connected to the AC system.

[0098] This embodiment uses short circuit ratio (SCR) and impedance angle as AC system parameters to verify the beneficial effects of the present invention.

[0099] Pick Figure 5 The direct-drive wind farm cable line of link 1 in the model shown is established as follows Figure 6 The Γ-type line model shown.

[0100] The high-frequency impedance of the complete wind farm is expressed as:

[0101] Z all =Z j +1 / (Y lian1 +Y lian2 +Y lian3 +Y lian4 )

[0102] Among them, Y lian1 represents link 1 in the state space model of permanent magnet direct-drive wind farm, Y lian2 represents link 2 in the state space model of permanent magnet direct-drive wind farm, Y lian3 represents link 3 in the state space model of permanent magnet direct-drive wind farm, Y lian4 represents link 4 in the state space model of permanent magnet direct drive wind farm;

[0103] According to the definition of impedance sensitivity, Z all The sensitivity to parameter α is expressed as:

[0104]

[0105] By calculating Z allThe impedance sensitivity of wind turbine control delay, current inner loop control parameters, LCL filter parameters, collector line parameters, and AC system parameters is used to obtain the quantitative relationship between the influence of each parameter on the high-frequency oscillation of the complete wind farm. The sensitivity of the impedance of the complete wind farm to the above parameters is as follows: Figure 7 And as shown in Table 1 below.

[0106] Table 1 Impedance sensitivity analysis results

[0107]

[0108] like Figure 7 As shown in Table 1, it can be seen that the control delay, LOL filter parameters, and collector line parameters have the greatest impact on the high-frequency oscillation of the entire wind farm.

[0109] It can be seen that the wind turbine impedance characteristic parameter sensitivity analysis method provided by the present invention can effectively quantify the influence of various parameters on the impedance characteristics of the wind farm, so that the key parameters that cause system instability can be optimized and adjusted in a targeted manner in the future. At the same time, this method does not require the internal structure and parameters of the wind turbine during implementation, which not only simplifies the analysis process, but also improves the analysis efficiency.

[0110] Example 3, reference Figure 8 , which is an embodiment of the present invention, provides a wind turbine impedance characteristic parameter sensitivity analysis system, including a construction module, a calculation module, and an identification module.

[0111] The construction module is used to construct the wind farm grid-connected system impedance model based on the DQ coordinate system; the calculation module is used to calculate the wind farm grid-connected system impedance sensitivity according to the wind farm grid-connected system DQ impedance; the identification module is used to identify the parameters with the greatest impact on the grid-connected system impedance based on the impedance sensitivity analysis results.

[0112] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, 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. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0113] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses.

[0114] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering, or processing in another suitable manner as necessary, and then stored in a computer memory.

[0115] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc. It should be noted that the above embodiments are only used to illustrate the technical solution of the present invention and are not limited. Although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

[0116] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for analyzing the sensitivity of wind turbine impedance characteristic parameters, characterized in that: include: Based on the DQ coordinate system, the wind farm grid-connected system impedance model is constructed; According to the DQ impedance of the wind farm grid-connected system, the impedance sensitivity of the wind farm grid-connected system is calculated; According to the impedance sensitivity analysis results, the parameters with the greatest impact on the impedance of the wind farm grid-connected system are obtained.

2. The wind turbine generator impedance characteristic parameter sensitivity analysis method according to claim 1, characterized in that: The DQ coordinate system includes a main circuit coordinate system and a control system coordinate system.

3. The wind turbine impedance characteristic parameter sensitivity analysis method according to claim 2, characterized in that: The main circuit coordinate system and the control system coordinate system include: the main circuit coordinate system is (d mf ,q mf ), rotates at the fundamental frequency ω0 as the angular velocity, and uses the PCC bus voltage for orientation; The coordinate system of the direct-drive wind turbine grid-side converter control system is (d cf ,q cf ), with the phase-locked loop angular frequency ω pll For angular velocity rotation, the voltage at the fan outlet is used for orientation; The conversion relationship between the variable x in the main circuit coordinate system and the control system coordinate system is expressed as: Among them, θ pll Represents the angle between the main circuit coordinate system and the control system coordinate system.

4. The wind turbine impedance characteristic parameter sensitivity analysis method according to claim 3, characterized in that: The wind farm grid-connected system impedance model includes a wind farm impedance model and an AC system impedance model; The wind farm grid-connected system includes splitting the system at the PCC port and selecting the PCC bus voltage U t mf As the input variable, the 33kV incoming line current of the wind farm is selected As the output variable, the wind farm impedance model Z is obtained WF And the AC system impedance model Z AC .

5. The wind turbine impedance characteristic parameter sensitivity analysis method according to claim 4, characterized in that: The wind farm grid-connected system DQ impedance includes the wind farm system DQ impedance obtained according to the wind farm system frequency domain model, which is expressed as: Among them, s′ represents a complex variable, A WF represents the state matrix, B WF represents the input matrix, C WF represents the output matrix, D WF represents the feedforward matrix, I represents the identity matrix, ΔU WF represents a small perturbation of the input variable, Y WF Represents a small perturbation of the output variable.

6. The wind turbine impedance characteristic parameter sensitivity analysis method according to claim 5, characterized in that: The wind farm frequency domain model comprises obtaining a wind farm system state space equation and an output equation according to a state space model of the wind farm system, linearizing the obtained equation at a steady-state operation point, and obtaining a wind farm frequency domain model; The state space model of the wind farm system is expressed as: Among them, X represents the state variable, U represents the input variable, and d represents the differential. represents the differential with respect to time; Define the wind farm input variables, expressed as: in, Indicates the voltage at the wind farm grid connection point, represents the d-axis component of the voltage at the wind farm connection point, represents the q-axis component of the voltage at the wind farm grid connection point, and T represents the transpose of the matrix; Define the wind farm output variables, expressed as: in, represents the output current of the wind farm, represents the d-axis component of the wind farm output current, The q-axis component of the wind farm output current; According to the definition, the state space equation and output equation of the wind farm system are established and expressed as: in, represents the time derivative of the wind farm state variable; The state space equation and output equation of the wind farm system are linearized at the steady-state operation point to obtain the frequency domain model of the wind farm system, which is expressed as: Where ΔX WF represents a small perturbation of the state variable, ΔU WF represents a small perturbation of the input variable, ΔY WF Represents a small perturbation of the output variable.

7. The wind turbine impedance characteristic parameter sensitivity analysis method according to claim 6, characterized in that: The impedance sensitivity includes transfer function sensitivity, real part sensitivity and imaginary part sensitivity; Transfer function sensitivity, expressed as: Among them, k represents the parameter for sensitivity analysis, and s represents the Laplace operator; Real part sensitivity, expressed as: H kRe (k,s)=Re{H k (k,s)} Imaginary sensitivity, expressed as: H kIm (k,s)=Im{H k (k,s)} The absolute value of impedance sensitivity determines the effect of parameter changes on system impedance. The positive or negative value of the sensitivity determines the direction in which the real and imaginary parts of the system impedance change with the parameters; According to the definition of impedance sensitivity, Z WF(s′) The sensitivity to parameter α is expressed as: Among them, Z all represents the total impedance, The wind farm impedance Z WF(s′) Sensitivity of the real part to the parameter α, The wind farm impedance Z WF(s′) The sensitivity of the imaginary part to the parameter α, j represents an imaginary number.

8. A system using the wind turbine impedance characteristic parameter sensitivity analysis method according to any one of claims 1 to 7, characterized in that: Including building module, calculation module and recognition module; The construction module is used to construct a wind farm grid-connected system impedance model based on a DQ coordinate system; The calculation module is used to calculate the impedance sensitivity of the wind farm grid-connected system according to the DQ impedance of the wind farm grid-connected system; The identification module is used to identify the parameter with the greatest impact on the impedance of the grid-connected system according to the impedance sensitivity analysis result.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the wind turbine impedance characteristic parameter sensitivity analysis method described in any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the wind turbine impedance characteristic parameter sensitivity analysis method described in any one of claims 1 to 7 are implemented.

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