A new energy unit impedance characteristic sensitivity simulation test method

Abstract

The application discloses a new energy unit impedance characteristic sensitivity simulation test method, which comprises the following steps: setting a unit control parameter as an operation parameter; obtaining the admittance parameter of the unit at each frequency through a hardware-in-the-loop test method; calculating an AC power grid side impedance; calculating a total impedance open loop transfer function of a grid-connected system from the admittance parameter and the grid-connected system impedance; calculating a grid-connected oscillation frequency and a phase margin according to the total impedance open loop transfer function of the system; and changing the unit control parameter and recalculating the grid-connected oscillation frequency and the phase margin. The method can calculate the impedance characteristic parameter sensitivity without obtaining the structure and parameters of a new energy unit controller, has the advantages of high efficiency and simple realization, and is especially suitable for the case where the structure and parameters of the new energy unit controller are unknown.

Description

Technical Field

[0001] This invention relates to the field of testing technology for new energy power units, and in particular to a method for simulating and testing the impedance characteristics and sensitivity of new energy power units. Background Technology

[0002] The grid connection of new energy uses power electronic equipment to realize the conversion and transmission of electrical energy. The multi-time-scale control characteristics of power electronic equipment have a profound impact on the broadband frequency domain characteristics of new energy power generation systems, resulting in broadband oscillations in grid-connected systems such as wind power and photovoltaics. Furthermore, the nonlinear strong coupling control characteristics of power electronic equipment make the broadband oscillation phenomenon have complex oscillation characteristics with oscillation frequency coupling.

[0003] In the analysis of oscillation mechanisms, there are mainly eigenvalue analysis and impedance analysis methods. The advantage of impedance analysis is that it can obtain the impedance model of asynchronous power supplies through measurement, without relying on the internal structure and parameters of the asynchronous power supplies. Large-scale renewable energy power plants are composed of a large number of renewable energy units connected by cables or submarine cables. The electrical topology within the renewable energy power plant has a significant impact on its impedance characteristics. At the same time, the topology within the plant may also change with the operating mode. In practical applications, it is necessary to consider the actual topology of the renewable energy power plant and the impact of its changes.

[0004] The unit impedance model can be obtained through two methods: analytical modeling and simulation testing. Analytical modeling requires the controller structure and control parameters, which are difficult to obtain in actual engineering, posing a significant challenge to the modeling process. Summary of the Invention

[0005] In view of the aforementioned existing problems, the present invention is proposed.

[0006] Therefore, to address the challenges of unanalyzable impedance modeling and inability to calculate traditional impedance characteristic parameters caused by the black-box nature of new energy unit controllers, this invention proposes a simulation test method for the grid-connected impedance sensitivity of new energy units. This method can calculate the parameter sensitivity of impedance characteristics without needing to obtain the structure and parameters of the new energy unit controller, and has advantages such as high efficiency and simple implementation. It is especially suitable for situations where the structure and parameters of the new energy unit controller are unknown.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for simulating and testing the impedance characteristics sensitivity of new energy generating units, comprising:

[0008] The unit control parameters are set as operating parameters, and the admittance parameters of the unit at each frequency are obtained through hardware-in-the-loop testing.

[0009] Calculate the AC grid-side impedance by using the admittance parameter and the grid-connected system impedance to calculate the open-loop transfer function of the total impedance of the grid-connected system.

[0010] Calculate the grid-connected oscillation frequency and phase margin based on the open-loop transfer function of the total system impedance, change the unit control parameters, and recalculate the grid-connected oscillation frequency and phase margin.

[0011] As a preferred embodiment of the impedance characteristic sensitivity simulation test method for new energy generating units described in this invention, the admittance parameters at each frequency include: establishing a hardware-in-the-loop test system for the new energy generating unit, applying small harmonic voltage perturbations Vh(fh) at different frequencies, obtaining the harmonic current response Ih(fh) of the unit, and then the admittance at frequency fh is Y. F(fh) =Ih(fh) / Vh(fh), where Y F(fh) It is a complex number.

[0012] As a preferred embodiment of the impedance characteristic sensitivity simulation test method for new energy generator units described in this invention, the calculation of AC grid-side impedance includes obtaining the impedance characteristic Zs(fh) = R0 + j(fh*X0 / f0) of the system at different frequencies based on the grid-connected short-circuit impedance Z0 = R0 + jX0 of the new energy generator unit, where f0 is the rated frequency of the system.

[0013] As a preferred embodiment of the impedance characteristic sensitivity simulation test method for new energy generating units described in this invention, the specific formula for calculating the open-loop transfer function of the total impedance of the grid-connected system is: Z(fh)=Zs(fh)*Y F(fh) .

[0014] As a preferred embodiment of the new energy unit impedance characteristic sensitivity simulation test method described in this invention, the calculation of the grid-connected oscillation frequency and phase margin includes calculating the grid-connected oscillation frequency fo based on the open-loop transfer function Z(fh) of the total impedance of the grid-connected system, that is, the frequency point that satisfies |Z(fo)|=1, and the corresponding phase margin is Gmar=180-Ang(Z(fo)), where Ang(Z(fo)) is the phase of the transfer function Z(fo) at the frequency fo.

[0015] As a preferred embodiment of the impedance characteristic sensitivity simulation test method for new energy units described in this invention, the calculation of grid-connected oscillation frequency and phase margin includes, for the control parameter i, changing it by 5% to adjust it to 95% or 105% of the original value, repeating the calculation steps to obtain the grid-connected oscillation as fo1 and the phase margin as Gmar1.

[0016] As a preferred embodiment of the impedance characteristic sensitivity simulation test method for new energy units described in this invention, the recalculation of grid-connected oscillation frequency and phase margin includes calculating the impedance sensitivity of control parameter i as follows: oscillation frequency sensitivity Sf = fo1 - fo, and oscillation damping sensitivity Sph = Gmar1 - Gmar.

[0017] As a preferred embodiment of the impedance characteristic sensitivity simulation test method for new energy units described in this invention, the recalculation of grid-connected oscillation frequency and phase margin includes the influence of oscillation frequency sensitivity Sf on the oscillation frequency of the grid-connected system. The greater the sensitivity, the greater the influence on the frequency.

[0018] The oscillation damping sensitivity is the effect of the Sph response control parameter on the oscillation damping of the grid-connected system. The greater the sensitivity, the greater the effect on the oscillation damping.

[0019] A computer device includes a memory and a processor, wherein the memory stores a computer program, characterized in that the processor executes the computer program to implement the steps of a method for simulating and testing the impedance characteristics sensitivity of a new energy unit.

[0020] A computer-readable storage medium storing a computer program thereon, characterized in that, when the computer program is executed by a processor, it implements the steps of a method for simulating and testing the impedance characteristics sensitivity of new energy generating units.

[0021] The beneficial effects of the present invention are as follows: The method of the present invention can calculate the impedance characteristic parameter sensitivity without obtaining the structure and parameters of the new energy unit controller, which has the advantages of high efficiency and simple implementation, and is especially suitable for situations where the structure and parameters of the new energy unit controller are unknown. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic flowchart of a method for simulating and testing the impedance characteristics of a new energy generating unit, provided as an embodiment of the present invention.

[0024] Figure 2 The circuit diagram of a new energy generator unit is provided as an embodiment of the present invention for a method of simulating and testing the impedance characteristics sensitivity of a new energy generator unit.

[0025] Figure 3The circuit diagram of a new energy generating unit and an AC power grid is provided for a new energy generating unit impedance characteristic sensitivity simulation test method according to an embodiment of the present invention. Detailed Implementation

[0026] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0027] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0028] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0029] This invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of this invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not adhering to the usual scale. Furthermore, the schematic diagrams are merely examples and should not be construed as limiting the scope of protection of this invention. In actual fabrication, the three-dimensional spatial dimensions of length, width, and depth should be included.

[0030] Furthermore, in the description of this invention, it should be noted that the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used solely for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. In addition, the terms "first," "second," or "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0031] Unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" in this invention should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; similarly, they can refer to mechanical connections, electrical connections, or direct connections, or indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0032] Example 1, referring to Figures 1-3 This is the first embodiment of the present invention, which provides a method for simulating and testing the impedance characteristics sensitivity of a new energy generating unit, including:

[0033] S1: Set the unit control parameters to operating parameters, and obtain the unit's admittance parameters at each frequency through hardware-in-the-loop testing.

[0034] S2: Calculate the AC grid-side impedance. Using the admittance parameter and the grid-connected system impedance, calculate the open-loop transfer function of the total impedance of the grid-connected system.

[0035] S3: Calculate the grid-connected oscillation frequency and phase margin based on the open-loop transfer function of the total system impedance, change the unit control parameters, and recalculate the grid-connected oscillation frequency and phase margin.

[0036] (1) As Figure 2 , 3 As shown, a hardware-in-the-loop test system is established for the new energy unit. Small harmonic voltage perturbations Vh(fh) at different frequencies are applied to obtain the harmonic current response Ih(fh) of the unit. Then, the admittance at frequency fh is Y. F(fh) =Ih(fh) / Vh(fh), where Y F(fh) It is a complex number;

[0037] (2) Based on the grid-connected short-circuit impedance Z0=R0+jX0 of the new energy unit, the impedance characteristics of the system at different frequencies are obtained as Zs(fh)=R0+j(fh*X0 / f0), where f0 is the rated frequency of the system.

[0038] (3) Calculate the open-loop transfer function of the total impedance of the grid-connected system: Z(fh)=Zs(fh)*Y F(fh)

[0039] (4) Calculate the grid-connected oscillation frequency fo based on the open-loop transfer function Z(fh) of the total impedance of the grid-connected system. That is, the frequency point that satisfies |Z(fo)|=1, and the corresponding phase margin is Gmar=180-Ang(Z(fo)), where Ang(Z(fo)) is the phase of the transfer function Z(fo) at frequency fo.

[0040] (5) For the control parameter i under consideration, change it by 5% to adjust it to 95% or 105% of the original value. Repeat steps (1) and (4) to obtain grid-connected oscillation fo1 and phase margin Gmar1.

[0041] (6) Calculate the impedance sensitivity of control parameter i:

[0042] The oscillation frequency sensitivity is Sf = fo1 - fo, and the oscillation damping sensitivity is Sph = Gmar1 - Gmar.

[0043] The oscillation frequency sensitivity Sf reflects the influence of this control parameter on the oscillation frequency of the grid-connected system. The greater the sensitivity, the greater the influence on the frequency.

[0044] The oscillation damping sensitivity, Sph, reflects the influence of this control parameter on the oscillation damping of the grid-connected system. The greater the sensitivity, the greater the influence on the oscillation damping.

[0045] The sensitivity analysis described above is of great significance for analyzing the factors affecting oscillation stability and optimizing control parameters.

[0046] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

[0047] Example 2

[0048] The second embodiment of the present invention differs from the first embodiment in that:

[0049] If the aforementioned functions 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, the technical solution of the present invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0050] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. 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... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0051] 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.

[0052] 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.

[0053] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0054] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A method for simulating and testing the impedance characteristics sensitivity of new energy generating units, characterized in that: include, The unit control parameters are set as operating parameters, and the admittance parameters of the unit at each frequency are obtained through hardware-in-the-loop testing. Calculate the AC grid-side impedance by using the admittance parameter and the grid-connected system impedance to calculate the open-loop transfer function of the total impedance of the grid-connected system. Calculate the grid-connected oscillation frequency and phase margin based on the open-loop transfer function of the total system impedance, change the unit control parameters, and recalculate the grid-connected oscillation frequency and phase margin. The admittance parameters at each frequency include: establishing a hardware-in-the-loop test system for the new energy unit, applying small harmonic voltage disturbances Vh(fh) at different frequencies, obtaining the harmonic current response Ih(fh) of the unit, and then the admittance at frequency fh is Y. F(fh) =Ih(fh) / Vh(fh), where Y F(fh) It is a complex number; The calculation of AC grid-side impedance includes obtaining the system impedance characteristics at different frequencies Zs(fh)=R0+j(fh*X0 / f0) based on the grid-connected short-circuit impedance of the new energy unit Z0=R0+jX0, where f0 is the system rated frequency; The specific formula for calculating the open-loop transfer function of the total impedance of the grid-connected system is: Z(fh) = Zs(fh) * Y F(fh) ; The calculation of the grid-connected oscillation frequency and phase margin includes calculating the grid-connected oscillation frequency fo based on the open-loop transfer function Z(fh) of the total impedance of the grid-connected system, that is, the frequency point that satisfies |Z(fo)|=1, and the corresponding phase margin is Gmar=180-Ang(Z(fo)), where Ang(Z(fo)) is the phase of the transfer function Z(fo) at frequency fo. The calculation of the grid-connected oscillation frequency and phase margin includes, for the control parameter i, changing it by 5%, adjusting it to 95% or 105% of the original, repeating the calculation steps, to obtain the grid-connected oscillation as fo1 and the phase margin as Gmar1. The recalculation of grid-connected oscillation frequency and phase margin includes calculating the impedance sensitivity of control parameter i as follows: oscillation frequency sensitivity Sf = fo1 - fo, and oscillation damping sensitivity as Sph = Gmar1 - Gmar.

2. The method for simulating and testing the impedance characteristics sensitivity of a new energy generating unit as described in claim 1, characterized in that: The recalculation of grid-connected oscillation frequency and phase margin includes the influence of oscillation frequency sensitivity Sf on the oscillation frequency of the grid-connected system. The greater the sensitivity, the greater the influence on the frequency. The oscillation damping sensitivity is the effect of the Sph response control parameter on the oscillation damping of the grid-connected system. The greater the sensitivity, the greater the effect on the oscillation damping.

3. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 2.

4. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 2.

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