Hardware-in-the-loop equivalent modeling and simulation method and device for wind power flexible direct delivery system

Abstract

The invention belongs to the technical field of new energy simulation, and discloses a hardware-in-the-loop equivalent modeling and simulation method and device for a wind power flexible direct delivery system. The modeling method comprises the following steps: modeling the converter of the wind turbine generator by adopting a switching function form; carrying out equivalent modeling on the wind power plant current collection line based on a constant power loss principle; a multi-pi cascade structure of a multi-resistor and multi-inductor parallel branch is adopted for modeling of an alternating current sending-out line; carrying out modeling on each bridge arm of the flexible direct current converter station by adopting an average value model; carrying out modeling on a receiving-end power grid by adopting a controlled voltage source and equivalent RLC impedance; and constructing a hardware-in-the-loop simulation equivalent model of the wind power flexible direct delivery system based on the modeling model. According to the method, equivalent processing and model simplification are respectively carried out on each part, the simulation requirement is reduced, meanwhile, the simulation precision and accuracy of the whole system can still be ensured, and finally, rapid and accurate simulation of the wind power through the flexible direct current grid-connected system is realized so as to adapt to the hardware-in-the-loop real-time simulation requirement.

Description

Technical Field

[0001] This invention belongs to the field of new energy grid connection simulation technology, and specifically relates to a hardware-in-the-loop equivalent modeling and simulation method and device for a wind power transmission system via flexible direct transmission. Background Technology

[0002] Flexible DC grid connection (full name "flexible DC transmission grid connection technology") is a new type of DC power transmission technology based on voltage source converter (VSC). Its core is to convert AC power (such as electricity generated by wind power and photovoltaic power) into DC power through converter, and then transmit it through DC lines before inverting it back into AC power and connecting it into the grid. This enables flexible connection between different power sources and the grid. It is named for its high control precision and flexible operation mode.

[0003] Flexible DC grid connection has become one of the main forms of wind power grid connection. To study and evaluate the characteristics and performance of wind power connected via flexible DC grid, system simulation analysis is often required. However, wind power connected via flexible DC grid involves a complex structure including multiple wind turbines within the wind farm, collector lines, transmission lines, a modular multilevel flexible DC converter station, and the receiving-end power grid. Electromagnetic transient modeling is difficult and simulation is slow. Especially for real-time simulation requirements such as hardware-in-the-loop testing, simulating a detailed model of the wind power connected via flexible DC grid requires enormous computational resources, making simulation highly challenging and severely limiting its feasibility. Summary of the Invention

[0004] The purpose of this invention is to provide a hardware-in-the-loop equivalent modeling and simulation method and apparatus for wind power transmission via flexible direct transmission systems, which solves the problems of existing technologies for real-time simulation requirements such as hardware-in-the-loop testing, which require huge computational resources and are difficult to simulate.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a hardware-in-the-loop equivalent modeling method for a wind power transmission system via flexible direct current, comprising: The wind turbine converter is modeled using a switching function to obtain an equivalent simulation model of the wind turbine converter. Based on the principle of constant power loss, an equivalent model of the wind farm collector line is obtained by performing an equivalent simulation model of the wind farm collector line. The AC transmission line is modeled using a multi-π cascade structure with multiple resistors and inductors in parallel branches to obtain an equivalent simulation model of the AC transmission line. The average value model is used to model each arm of the flexible DC converter station to obtain the equivalent simulation model of the flexible DC converter station; The receiving-end power grid is modeled using a controlled voltage source and an equivalent RLC impedance to obtain an equivalent simulation model of the receiving-end power grid. A hardware-in-the-loop simulation equivalent model of the wind power transmission system via flexible DC power conversion is constructed based on the equivalent simulation models of the wind turbine converter, wind farm collector lines, AC transmission lines, flexible DC converter stations, and receiving-end power grids.

[0006] A further improvement of this invention is that: in the step of modeling the wind turbine converter using switching functions to obtain an equivalent simulation model of the wind turbine converter, a logic switching function is used. S xy Describe the bridge arm switch. S xy = 1 indicates that the switch on the bridge arm is on. S xy = 0 indicates that the switch on the bridge arm is off; subscript x = r indicates the machine-side converter, x = g indicates the grid-side converter, and subscripts y = a, b, c indicate the three-phase circuits a, b, and c respectively; the switching function of the switch on the lower bridge arm is expressed as 1- S xy .

[0007] A further improvement of the present invention is that: in the step of performing equivalent modeling of the wind farm collector wire based on the principle of constant power loss to obtain the equivalent simulation model of the wind farm collector wire, the basic principle is that the power loss on the collector network remains unchanged before and after equivalence, and the wind farm collector network is equivalent to aggregate impedance.

[0008] A further improvement of this invention lies in the following step: in the step of modeling the AC transmission line using a multi-π cascade structure with multiple resistors and inductors in parallel branches to obtain an equivalent simulation model of the AC transmission line, the resistance per unit length is determined according to the material and model of the AC transmission line. r ,inductance l The frequency-varying characteristics of the line are analyzed. Modeling of a multi-π cascade structure with parallel branches of multiple resistors and inductors involves first fitting the frequency-varying characteristics of the line parameters per unit length using vector fitting to obtain the equivalent resistance and inductance parameters of the parallel branches. The fitting of the frequency-varying characteristics of the line parameters per unit length is considered as fitting the sum of rational fractional transfer functions to the amplitude-frequency characteristics of the line's admittance per unit length. After fitting, the equivalent resistance of the parallel branches per unit length is obtained. and inductor The propagation delay of the line is approximated by using a multi-π cascade structure, and the number of multi-π cascade structures is determined according to the required bandwidth accuracy.

[0009] A further improvement of this invention is that: in the step of modeling each bridge arm of the flexible DC converter station using an average value model to obtain the equivalent simulation model of the flexible DC converter station, an average value model is used for modeling each bridge arm of the flexible DC converter station; under normal operating conditions, the equivalent resistance is set. Rsm = 0, where the equivalent voltage source u armeq and equivalent current source i Ceq They are respectively: (7) in a = N on / N This represents the ratio of the number of conducting submodules in the bridge arm to the total number of submodules. u C.tot Indicates the middle of the bridge arm N The sum of the capacitor voltages of each submodule, C eq = C 0 / N Indicates the capacitance value of the submodule C 0 divided by the number of bridge arm sub-modules, i arm Indicates the bridge arm current; Under the locked-down state of the flexible DC converter station, the following settings are configured: (8) Among them, the resistance when thyristors T1, T2 and T3 are turned on. R T1on , R T2on and R T3on Based on the on-resistance of the anti-parallel diodes in the bridge arm submodules of the flexible DC converter station R Don Set as: (9).

[0010] A further improvement of this invention is that the step of modeling the receiving-end power grid using a controlled voltage source and an equivalent RLC impedance to obtain an equivalent simulation model of the receiving-end power grid specifically includes: Establish the voltage output waveform of the controlled voltage source; Obtain the equivalent impedance of the receiving-end power grid Z dq And convert the two-dimensional impedance into a one-dimensional equivalent impedance. Z eq ; One-dimensional equivalent impedance within the frequency band of interest Z eq Convert to order N The low-order transfer function; The receiving-end power grid modeling is completed based on the equivalent RLC circuit with a low-order transfer function.

[0011] Secondly, the present invention provides a hardware-in-the-loop equivalent simulation method for a wind power transmission system via flexible direct transmission, comprising: performing simulation on the equivalent simulation model of the wind power transmission system via flexible direct transmission constructed by the aforementioned hardware-in-the-loop equivalent modeling method.

[0012] Thirdly, the present invention provides a hardware-in-the-loop equivalent modeling device for a wind power transmission system via flexible direct transmission, comprising: The first building unit is used to model the wind turbine converter in the form of a switching function to obtain an equivalent simulation model of the wind turbine converter. The second building unit is used to perform equivalent modeling of the wind farm collector line based on the constant power loss principle, and obtain the equivalent simulation model of the wind farm collector line. The third building unit is used to model the multi-π cascade structure of the AC transmission line with multiple resistors and inductors in parallel branches, and obtain the equivalent simulation model of the AC transmission line. The fourth building unit is used to model each arm of the flexible DC converter station using the average value model to obtain the equivalent simulation model of the flexible DC converter station. The fifth building block is used to model the receiving-end power grid using a controlled voltage source and equivalent RLC impedance to obtain an equivalent simulation model of the receiving-end power grid. The sixth building unit is used to construct a hardware-in-the-loop simulation equivalent model of the wind power transmission system via flexible DC transmission, based on the equivalent simulation models of the wind turbine converter, wind farm collector lines, AC transmission lines, flexible DC converter stations, and receiving-end power grids.

[0013] Fourthly, the present invention provides an electronic device, including a processor and a memory, wherein the processor is used to execute a computer program stored in the memory to implement the hardware-in-the-loop equivalent modeling method for the wind power transmission system via flexible direct transmission.

[0014] Fifthly, the present invention provides a computer-readable storage medium storing at least one instruction, which, when executed by a processor, implements the hardware-in-the-loop equivalent modeling method for wind power transmission via flexible direct current transmission system.

[0015] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a hardware-in-the-loop equivalent modeling and simulation method and apparatus for a wind power transmission system via flexible DC transmission. The method includes: modeling the wind turbine converter using a switching function to obtain an equivalent simulation model of the wind turbine converter; modeling the wind farm collector lines based on the constant power loss principle to obtain an equivalent simulation model of the wind farm collector lines; modeling the AC transmission line using a multi-π cascade structure with multiple resistors and inductors in parallel branches to obtain an equivalent simulation model of the AC transmission line; modeling each arm of the flexible DC converter station using an average value model to obtain an equivalent simulation model of the flexible DC converter station; modeling the receiving-end grid using a controlled voltage source and equivalent RLC impedance to obtain an equivalent simulation model of the receiving-end grid; and constructing a hardware-in-the-loop simulation equivalent model of the wind power transmission system via flexible DC transmission based on the equivalent simulation models of the wind turbine converter, wind farm collector lines, AC transmission lines, flexible DC converter station, and receiving-end grid. This invention simplifies the model by performing equivalent processing on the wind turbine converter, wind farm collection line, AC transmission line, flexible DC converter station, and receiving-end power grid in the system, thereby reducing simulation requirements. At the same time, it can still ensure the simulation accuracy and precision of the overall system, and finally realize the rapid and accurate simulation of wind power through the flexible DC grid-connected system to meet the hardware-in-the-loop real-time simulation requirements.

[0016] Based on the modeling method proposed in this invention, equivalent modeling of wind power connected to a flexible DC grid system can be performed, reducing computational resource consumption while ensuring solution accuracy and precision. This allows for real-time simulation of the flexible DC grid system using minimal hardware computing resources, reducing the difficulty of hardware-in-the-loop testing and the need for substantial hardware investment.

[0017] This invention can be applied to modeling and real-time simulation of wind power connected to a flexible DC grid system, thereby supporting hardware-in-the-loop testing requirements and enabling testing and verification of objects under test such as wind turbine generators. Attached Figure Description

[0018] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 A schematic diagram of the object structure for modeling a wind power system connected to a flexible DC grid. Figure 2 This is a flowchart illustrating the modeling method for wind power connected to a flexible DC grid system applicable to hardware-in-the-loop real-time simulation according to an embodiment of the present invention. Figure 3 This is a schematic diagram of a wind turbine converter. Figure 4 This is a schematic diagram of the power collection network for a wind farm. Figure 5 A schematic diagram of a multi-π cascade structure for multiple parallel branches of resistors and inductors in an AC transmission line; Figure 6 A schematic diagram of the average value model of the bridge arm of the flexible DC converter station; Figure 7 A schematic diagram of receiving-end power grid modeling based on a controlled voltage source and equivalent RLC impedance; Figure 8 For real pole terms " c n / ( sa n The diagram can be converted into a parallel RC branch or a series RL branch; where (a) represents the impedance and (b) represents the admittance. Figure 9 For the conjugate complex pole term "[ c n1 / ( sa n1 )]+[ c n2 / ( sa n2 This can be converted into a schematic diagram of an RLC hybrid branch; where (a) is the impedance and (b) is the admittance. Figure 10 For constant terms and linear terms e + sh This can be converted into a schematic diagram of an RL series branch or an RC parallel branch; where (a) is the impedance and (b) is the admittance. Figure 11 The diagrams show a comparison between the simplified model and the detailed system model proposed in this invention under typical scenarios; (a) is a comparison of AC fault scenarios at the sending end; (b) is a comparison of DC fault scenarios; (c) is a comparison of system fault scenarios at the receiving end; and (d) is a comparison of scenarios with changes in control commands. Figure 12 This is a schematic diagram of the hardware-in-the-loop equivalent modeling device for a wind power transmission system via flexible direct transmission, provided in an embodiment of the present invention. Figure 13 This is a schematic diagram of the structure of an electronic device according to an embodiment of the present invention. Detailed Implementation

[0019] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0020] The following detailed description is exemplary and intended to provide further detailed explanation of the invention. Unless otherwise specified, all technical terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in this invention is for describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention.

[0021] To achieve hardware-in-the-loop equivalent simulation modeling of wind power transmission systems via flexible direct transmission, this invention addresses the following: Figure 1 The wind power system shown is connected to the grid via flexible DC. It models five parts: wind turbine converter, wind farm collection line, AC transmission line, flexible DC converter station and receiving-end grid, to achieve system equivalence and simplification while maintaining system simulation accuracy.

[0022] In this invention, the wind turbine converter is modeled using a switching function; the wind farm collector lines are modeled using a constant power loss principle for aggregated equivalent modeling; and the AC transmission lines are modeled using multiple parallel branches with multiple resistors and inductors. π The cascaded structure is modeled; the flexible DC converter station is modeled using an average value model; and the receiving-end power grid is modeled using a controlled voltage source and an equivalent RLC impedance.

[0023] Please see Figure 2 As shown, this embodiment of the invention provides a hardware-in-the-loop equivalent modeling method for a wind power transmission system via flexible direct current, comprising the following steps: S101. The wind turbine converter is modeled using a switching function to obtain an equivalent simulation model of the wind turbine converter. Regarding the attached Figure 3 The converter, the core grid-connected equipment of the wind turbine shown, is modeled using switching functions. Specifically, logical switching functions are employed. S xy Describe the bridge arm switch. S xy = 1 indicates that the switch on the bridge arm is on. S xy = 0 indicates that the switch on the bridge arm is off. Subscript x = r represents the machine-side converter, x = g represents the grid-side converter, and subscripts y = a, b, c represent the three-phase circuits a, b, and c, respectively. Since the upper and lower switches on the same bridge arm conduct alternately, the switching function of the lower switch on the bridge arm can be expressed as 1- S xy Taking the generator-side converter as an example, the switching function is modeled as follows: (1) (2) in, , , These are the phase currents of the machine-side converter, specifically phases a, b, and c. For the machine-side converter resistance; For the machine-side converter inductor; , , These are the three-phase voltages of the generator-side converter; v rdc = v rdc+ - v rdc- ; For the DC-side capacitor of the machine-side converter; , These represent the positive and negative currents of the DC line, respectively. The grid-side converter can be modeled using the same method.

[0024] S102. Based on the principle of constant power loss, the equivalent model of the wind farm collector line is modeled to obtain the equivalent simulation model of the wind farm collector line; For the attached Figure 4 The wind farm collector network shown is modeled using an equivalent method based on the principle of constant power loss. Assuming that the power loss on the collector network remains unchanged before and after equivalence, the wind farm collector network is equivalent to a pooled impedance. (See attached diagram.) Figure 4 For example, the method for calculating the aggregate impedance of a collector network using the constant power loss method is as follows: (3) in, Z weq Indicates the aggregate impedance of the collector network. I w For wind farm output current, S loss This indicates the power loss on the original wind farm's collector network. This provides the output current for each wind turbine.

[0025] (4) in, , , , , , These are the output line impedances of each wind turbine unit.

[0026] S103. Model the AC transmission line using a multi-π cascade structure with multiple resistors and inductors in parallel branches to obtain an equivalent simulation model of the AC transmission line; For the AC transmission line between the wind farm grid connection point and the flexible DC converter station, the following method is adopted. Figure 5The multi-π cascade structure of multiple resistors and inductors in parallel branches is modeled as shown. Based on the material and model of the AC transmission line, its resistance per unit length can be determined. r ,inductance l The frequency-varying characteristics of the circuit are observed. Based on this, the multi-π cascade structure modeling of parallel branches with multiple resistors and inductors first uses vector fitting to fit the frequency-varying characteristics of the parameters per unit length of the line, obtaining the parameters of the equivalent resistance and inductance on the parallel branches. For the attached... Figure 5 The equivalent resistance of the parallel branches in each π-stage of the multi-π cascaded structure shown is... and inductor The parameters are: (5) (6) in π For the length of each π element, we have π = / p , To exchange and collect the total length of the line, p The number of π elements. Fitting the frequency-varying characteristics of the line's unit-length parameters can be viewed as fitting the amplitude-frequency characteristics of the line's unit-length admittance to the sum of several rational fractional transfer functions. After fitting, the parameters of the parallel branches per unit length can be obtained. R i and L i .

[0027] Furthermore, the propagation delay of the line is approximated using a multi-π cascade structure. The number of multi-π cascade structures is determined based on the required bandwidth accuracy; typically, a 5-order parallel branch, 5-level π structure unit can be selected.

[0028] S104. The average value model is used to model each arm of the flexible DC converter station to obtain the equivalent simulation model of the flexible DC converter station; For each bridge arm of the flexible DC converter station, the following method is adopted: Figure 6 The average value model shown is used for modeling. Under normal operating conditions, the equivalent resistance is set. R sm = 0, where the equivalent voltage source u armeq and equivalent current source i Ceq They are respectively: (7) in a = N on / NThis represents the ratio of the number of conducting submodules in the bridge arm to the total number of submodules. u C.tot Indicates the middle of the bridge arm N The sum of the capacitor voltages of each submodule, C eq = C 0 / N Indicates the capacitance value of the submodule C 0 divided by the number of bridge arm sub-modules, i arm This indicates the bridge arm current.

[0029] Under the locked-down state of the flexible DC converter station, the following settings are configured: (8) Among them, the resistance when thyristors T1, T2 and T3 are turned on. R T1on , R T2on and R T3on Based on the on-resistance of the anti-parallel diodes in the bridge arm submodules of the flexible DC converter station R Don Set as: (9) S105. The receiving-end power grid is modeled using a controlled voltage source and an equivalent RLC impedance to obtain an equivalent simulation model of the receiving-end power grid; For the receiving-end power grid, the following method is adopted. Figure 7 The controlled voltage source and equivalent RLC impedance shown are modeled, and the modeling process includes the following four steps: S1051. Establish the voltage output waveform of the controlled voltage source; For different simulation and testing purposes, the controlled voltage source can be an ideal voltage source or output a specific waveform of three-phase voltage. The receiving-end power grid is equivalent to "controlled voltage source + equivalent RLC impedance". In implementation, it is necessary to set the voltage value of the controlled voltage source, i.e., the voltage output waveform.

[0030] S1052. Obtain the equivalent impedance of the receiving-end power grid. Z dq And convert the two-dimensional impedance into a one-dimensional equivalent impedance. Z eq ; The full-frequency dq-axis equivalent impedance characteristics of the receiving-end power grid are obtained using methods such as impedance scanning, simulation, or modeling analysis. Z dq , is represented as: (10) To obtain the full-band dq-axis equivalent impedance characteristics of the receiving-end power grid Zdq Then, through averaging, the two-dimensional impedance is converted into a one-dimensional equivalent impedance. Z eq Conversion: (11) in j It is the imaginary unit.

[0031] S1053. Within the frequency band of interest, convert the equivalent impedance to an order of [order missing]. N The low-order transfer function; Based on the range of frequency bands of interest, preset the center point of the frequency bands of interest. w r and bandwidth h The equivalent range is [ w r - h / 2, w r + h / 2]. Within this frequency band, for one-dimensional equivalent impedance Z eq Sampling is performed to obtain a series of frequency response data. Based on the sampled data, a one-dimensional equivalent impedance is fitted within the frequency band of interest. Z eq Convert to order N low-order transfer function : (12) Where s is the Laplace operator; Based on the given fitting accuracy threshold r The transfer function coefficients are obtained by iterative optimization using the least squares method. a n , c n , d and h .

[0032] S1054. Based on the equivalent RLC circuit with low-order transfer function, complete the receiving-end power grid modeling; Based on the obtained low-order transfer function, the equivalent RLC circuit is recursively derived. For each term in the low-order transfer function, the equivalent RLC impedance branch is constructed as follows: Wherein: when a n When the value is a real number, the first term is the real number extreme term. c n / ( sa n As an impedance, it can be converted into an RC parallel branch, as shown in the attached diagram. Figure 8As shown in (a); it can be converted into an RL series branch as an admittance, as shown in the appendix. Figure 8 As shown in (b).

[0033] when a n When the number is a conjugate complex number, the first term is the conjugate complex pole term. c n1 / ( sa n1 )]+[ c n2 / ( sa n2 As an impedance, it can be converted into a mixed branch dominated by RLC parallel connection, as shown in the attached figure. Figure 9 As shown in (a); the admittance can be converted into a hybrid branch dominated by RLC series, as shown in the appendix. Figure 9 As shown in (b).

[0034] The second and third terms are a constant term and a linear term, respectively. d + sh As an impedance, it can be converted into an RL series branch, as shown in the attached figure. Figure 10 As shown in (a); as admittance, it can be converted into an RC parallel branch, as shown in the appendix. Figure 10 As shown in (b).

[0035] Based on the transfer function expression (12), the overall circuit structure reflected by equation (12) can be constructed by using the series form of RLC impedance or the parallel form of admittance, based on the equivalent circuit transformation. Furthermore, the equivalent grid-connected impedance can be modeled by using the series-parallel structure of RLC impedance.

[0036] S106. Construct a hardware-in-the-loop simulation equivalent model of the wind power transmission system via flexible DC power transmission based on the equivalent simulation models of the wind turbine converter, wind farm collector lines, AC transmission lines, flexible DC converter stations, and receiving-end power grids.

[0037] Using the methods described above, the wind turbine converter, wind farm collection lines, AC transmission lines, flexible DC converter station, and receiving-end power grid are modeled respectively, thereby completing the modeling of a wind power system connected to a flexible DC grid suitable for hardware-in-the-loop real-time simulation.

[0038] The technical solution proposed in this invention simplifies and equivalences the model of a wind power transmission system via flexible DC transmission, making it suitable for scenarios requiring rapid simulation and testing, such as hardware-in-the-loop real-time computation. Simultaneously, the proposed solution effectively preserves the accuracy of the system's dynamic characteristics, ensuring the effectiveness of simulation and testing. A comparison of simulation results between the simplified model and the detailed model of wind power transmission via flexible DC transmission in typical scenarios is attached. Figure 11As shown, the modeling method proposed in this invention can achieve good simulation accuracy.

[0039] Wind power connected to the grid via flexible DC has become one of the main forms of wind power grid connection. The simulation analysis of wind power connected to the grid via flexible DC requires modeling multiple wind turbines, collection lines, AC transmission lines of the wind farm, flexible DC converter stations and receiving-end power grids in the wind farm.

[0040] Conventional modeling methods, while detailed, involve enormous computational demands, consuming significant hardware resources in hardware-in-the-loop (HIL) real-time simulations and drastically increasing simulation analysis costs. To address this, this invention proposes a modeling method for wind power systems connected to flexible DC grids, suitable for HIL real-time simulations. This method performs equivalent representations of the wind turbine converter, wind farm collector lines, AC transmission lines, flexible DC converter station, and receiving-end grid, reducing model complexity while maintaining sufficient simulation accuracy and precision, thus achieving applicability to HIL real-time simulations.

[0041] This invention provides a hardware-in-the-loop equivalent simulation method for a wind power transmission system via flexible direct transmission, comprising: performing simulation based on the hardware-in-the-loop equivalent model of the wind power transmission system via flexible direct transmission constructed by the hardware-in-the-loop equivalent modeling method described in the above embodiments.

[0042] Please see Figure 12 As shown, this embodiment of the invention also provides a hardware-in-the-loop equivalent modeling device for a wind power transmission system via flexible direct current, comprising: The first building unit is used to model the wind turbine converter in the form of a switching function to obtain an equivalent simulation model of the wind turbine converter. The second building unit is used to perform equivalent modeling of the wind farm collector line based on the constant power loss principle, and obtain the equivalent simulation model of the wind farm collector line. The third building unit is used to model the multi-π cascade structure of the AC transmission line with multiple resistors and inductors in parallel branches, and obtain the equivalent simulation model of the AC transmission line. The fourth building unit is used to model each arm of the flexible DC converter station using the average value model to obtain the equivalent simulation model of the flexible DC converter station. The fifth building block is used to model the receiving-end power grid using a controlled voltage source and equivalent RLC impedance to obtain an equivalent simulation model of the receiving-end power grid. The sixth building unit is used to construct a hardware-in-the-loop simulation equivalent model of the wind power transmission system via flexible DC transmission, based on the equivalent simulation models of the wind turbine converter, wind farm collector lines, AC transmission lines, flexible DC converter stations, and receiving-end power grids.

[0043] Please see Figure 13 As shown, this embodiment of the invention provides an electronic device 100 for implementing a hardware-in-the-loop equivalent modeling method for wind power transmission via flexible direct transmission systems; the electronic device 100 includes a memory 101, at least one processor 102, a computer program 103 stored in the memory 101 and executable on the at least one processor 102, and at least one communication bus 104.

[0044] The memory 101 can be used to store the computer program 103. The processor 102 implements the steps of the hardware-in-the-loop equivalent modeling method for a wind power transmission system via flexible direct transmission as described in the embodiment by running or executing the computer program stored in the memory 101 and calling the data stored in the memory 101. The memory 101 may mainly include a program storage area and a data storage area. The program storage area may store the operating system, at least one application program required for a function (such as sound playback function, image playback function, etc.), etc.; the data storage area may store data created based on the use of the electronic device 100 (such as audio data), etc. In addition, the memory 101 may include non-volatile memory, such as hard disk, memory, plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, at least one disk storage device, flash memory device, or other non-volatile solid-state storage device.

[0045] The at least one processor 102 may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The processor 102 may be a microprocessor or any conventional processor. The processor 102 is the control center of the electronic device 100, connecting various parts of the electronic device 100 via various interfaces and lines.

[0046] The memory 101 in the electronic device 100 stores multiple instructions to implement a hardware-in-the-loop equivalent modeling method for a wind power transmission system via flexible direct current. The processor 102 can execute the multiple instructions to achieve the following: The wind turbine converter is modeled using a switching function to obtain an equivalent simulation model of the wind turbine converter. Based on the principle of constant power loss, an equivalent model of the wind farm collector line is obtained by performing an equivalent simulation model of the wind farm collector line. The AC transmission line is modeled using a multi-π cascade structure with multiple resistors and inductors in parallel branches to obtain an equivalent simulation model of the AC transmission line. The average value model is used to model each arm of the flexible DC converter station to obtain the equivalent simulation model of the flexible DC converter station; The receiving-end power grid is modeled using a controlled voltage source and an equivalent RLC impedance to obtain an equivalent simulation model of the receiving-end power grid. A hardware-in-the-loop simulation equivalent model of the wind power transmission system via flexible DC power conversion is constructed based on the equivalent simulation models of the wind turbine converter, wind farm collector lines, AC transmission lines, flexible DC converter stations, and receiving-end power grids.

[0047] If the modules / units integrated in the electronic device 100 are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a portable hard drive, a magnetic disk, an optical disk, a computer memory, and a read-only memory (ROM).

[0048] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied 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.

[0049] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0050] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0051] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A hardware-in-the-loop equivalent modeling method for wind power transmission via flexible direct current transmission systems, characterized in that, include: The wind turbine converter is modeled using a switching function to obtain an equivalent simulation model of the wind turbine converter. Based on the principle of constant power loss, an equivalent model of the wind farm collector line is obtained by performing an equivalent simulation model of the wind farm collector line. The AC transmission line is modeled using a multi-π cascade structure with multiple resistors and inductors in parallel branches to obtain an equivalent simulation model of the AC transmission line. The average value model is used to model each arm of the flexible DC converter station to obtain the equivalent simulation model of the flexible DC converter station; The receiving-end power grid is modeled using a controlled voltage source and an equivalent RLC impedance to obtain an equivalent simulation model of the receiving-end power grid. A hardware-in-the-loop simulation equivalent model of the wind power transmission system via flexible DC power conversion is constructed based on the equivalent simulation models of the wind turbine converter, wind farm collector lines, AC transmission lines, flexible DC converter stations, and receiving-end power grids.

2. The hardware-in-the-loop equivalent modeling method for wind power transmission via flexible direct transmission system according to claim 1, characterized in that, In the step of modeling the wind turbine converter using switching functions to obtain an equivalent simulation model of the wind turbine converter, logic switching functions are employed. S xy Describe the bridge arm switch. S xy = 1 indicates that the switch on the bridge arm is on. S xy = 0 indicates that the switch on the bridge arm is off; subscript x = r indicates the machine-side converter, x = g indicates the grid-side converter, and subscripts y = a, b, c indicate the three-phase circuits a, b, and c respectively; the switching function of the switch on the lower bridge arm is expressed as 1- S xy .

3. The hardware-in-the-loop equivalent modeling method for wind power transmission via flexible direct transmission system according to claim 1, characterized in that, In the step of performing equivalent modeling of the wind farm collector wire based on the principle of constant power loss to obtain the equivalent simulation model of the wind farm collector wire, the basic principle is that the power loss on the collector network remains unchanged before and after equivalence, and the wind farm collector network is equivalent to aggregate impedance.

4. The hardware-in-the-loop equivalent modeling method for wind power transmission via flexible direct transmission system according to claim 1, characterized in that, In the step of modeling the AC transmission line using a multi-π cascade structure with parallel branches of multiple resistors and inductors to obtain an equivalent simulation model of the AC transmission line, the resistance per unit length is determined based on the material and model of the AC transmission line. r ,inductance l Frequency-varying characteristics; Modeling of a multi-π cascade structure with multiple resistors and inductors in parallel branches: First, the frequency-varying characteristics of the parameters per unit length of the line are fitted using the vector fitting method to obtain the parameters of the equivalent resistance and inductance on the parallel branches. The frequency-varying characteristic fitting of the line unit length parameter is regarded as fitting the amplitude-frequency characteristic of the line unit length admittance to the sum of the rational fractional transfer functions. After fitting, the equivalent resistance of the parallel branch per unit length is obtained. and inductor ; The propagation delay of the line is approximated by using a multi-π cascade structure, and the number of multi-π cascade structures is determined according to the required bandwidth accuracy.

5. The hardware-in-the-loop equivalent modeling method for wind power transmission via flexible direct transmission system according to claim 1, characterized in that, In the step of modeling each bridge arm of the flexible DC converter station using an average value model to obtain the equivalent simulation model of the flexible DC converter station, the average value model is used for modeling each bridge arm of the flexible DC converter station; under normal operating conditions, the equivalent resistance is set. R sm = 0, where the equivalent voltage source u armeq and equivalent current source i Ceq They are respectively: (7) in a = N on / N This represents the ratio of the number of conducting submodules in the bridge arm to the total number of submodules. u C.tot Indicates the middle of the bridge arm N The sum of the capacitor voltages of each submodule, C eq = C 0 / N Indicates the capacitance value of the submodule C 0 divided by the number of bridge arm sub-modules i arm Indicates the bridge arm current; Under the locked-down state of the flexible DC converter station, the following settings are configured: (8) Among them, the resistance when thyristors T1, T2 and T3 are turned on. R T1on , R T2on and R T3on Based on the on-resistance of the anti-parallel diodes in the bridge arm submodules of the flexible DC converter station R Don Set as: (9)。 6. The hardware-in-the-loop equivalent modeling method for wind power transmission via flexible direct transmission system according to claim 1, characterized in that, The steps for modeling the receiving-end power grid using a controlled voltage source and equivalent RLC impedance to obtain an equivalent simulation model of the receiving-end power grid specifically include: Establish the voltage output waveform of the controlled voltage source; Obtain the equivalent impedance of the receiving-end power grid Z dq And convert the two-dimensional impedance into a one-dimensional equivalent impedance. Z eq ; One-dimensional equivalent impedance within the frequency band of interest Z eq Convert to order N The low-order transfer function; The receiving-end power grid modeling is completed based on the equivalent RLC circuit with a low-order transfer function.

7. A hardware-in-the-loop equivalent simulation method for wind power transmission via flexible direct current transmission system, characterized in that, include: The simulation is performed using the equivalent hardware-in-the-loop simulation model of the wind power transmission system constructed based on the hardware-in-the-loop equivalent modeling method of the wind power transmission system via flexible direct transmission as described in any one of claims 1 to 6.

8. A hardware-in-the-loop equivalent modeling device for a wind power transmission system via flexible direct current, characterized in that, include: The first building unit is used to model the wind turbine converter in the form of a switching function to obtain an equivalent simulation model of the wind turbine converter. The second building unit is used to perform equivalent modeling of the wind farm collector line based on the constant power loss principle, and obtain the equivalent simulation model of the wind farm collector line. The third building unit is used to model the multi-π cascade structure of the AC transmission line with multiple resistors and inductors in parallel branches, and obtain the equivalent simulation model of the AC transmission line. The fourth building unit is used to model each arm of the flexible DC converter station using the average value model to obtain the equivalent simulation model of the flexible DC converter station. The fifth building block is used to model the receiving-end power grid using a controlled voltage source and equivalent RLC impedance to obtain an equivalent simulation model of the receiving-end power grid. The sixth building unit is used to construct a hardware-in-the-loop simulation equivalent model of the wind power transmission system via flexible DC transmission, based on the equivalent simulation models of the wind turbine converter, wind farm collector lines, AC transmission lines, flexible DC converter stations, and receiving-end power grids.

9. An electronic device, characterized in that, It includes a processor and a memory, the processor being used to execute a computer program stored in the memory to implement the hardware-in-the-loop equivalent modeling method for wind power transmission via flexible direct transmission system as described in any one of claims 1 to 6.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores at least one instruction, which, when executed by a processor, implements the hardware-in-the-loop equivalent modeling method for wind power transmission via flexible direct transmission system as described in any one of claims 1 to 6.

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