Frequency scanning method, device and equipment for power system equipment

Abstract

The invention relates to a frequency scanning method, device and equipment for power system equipment, and the method comprises the steps: building a frequency domain steady-state model for the frequency scanning process of a power electronic device, and determining a frequency scanning range; determining an initial scanning frequency based on the frequency scanning range, and extracting a nonlinear equation corresponding to the to-be-solved variable from the frequency domain steady-state model according to the to-be-solved variable based on the initial scanning frequency; and iteratively solving the nonlinear equation by using a Newton-Raphson method, determining an initial value based on a preset initial value resetting strategy when a solving result meets a reselection initial value condition, and re-executing the step of iteratively solving the nonlinear equation by using the Newton-Raphson method based on the initial value until a new solving result does not meet the reselection initial value condition. Therefore, the problems that focusing of dominant components is not facilitated due to PWM dynamic influence in the time domain implementation process, the efficiency of an algorithm is affected, and potential safety hazards exist in time domain frequency scanning are solved. And the interpretability and applicability of the method are improved.

Description

Technical Field

[0001] The present invention relates to the field of power electronics technology, and in particular to a frequency scanning method, device and equipment for power system equipment. Background Art

[0002] Under the background of "dual carbon", the new power system presents a "double high" form of "high proportion of new (renewable) energy" and "high proportion of power electronic devices (converters)". The introduction of converters (especially complex control loops) has profoundly changed the dynamic characteristics of the power system, making the stability of the power system prominent, especially the problem of wide-band oscillation that seriously threatens the safe and stable operation of the power system. For the purpose of privacy protection, converter manufacturers generally do not disclose their detailed control loops. Transfer function models represented by impedance models are often used in engineering to evaluate the risk of wide-band oscillations.

[0003] In the related technology, system operators and equipment manufacturers tend to obtain the impedance frequency response of the equipment through "frequency scanning". The so-called "frequency scanning" is a time domain implementation process. Taking the measurement of the one-dimensional closed-loop impedance on the AC side of a three-phase converter as an example, a set of three-phase positive sequence voltages with sufficiently small amplitudes are injected into the AC side, and the three-phase positive sequence current response with the same frequency is collected. The obtained frequency response is ffted and then algebraically operated to obtain the frequency scanning result. This process can be achieved through electromagnetic transient simulation or prototype experiment.

[0004] However, the relevant technology has a series of problems related to signal measurement technology. First, the power system is generally concerned with the dynamic response of the dominant frequency below the converter switching frequency, but the influence of PWM dynamics in the time domain implementation process is usually difficult to ignore, that is, it is not conducive to focusing on the influence of the dominant component. Secondly, there are obvious transient processes in time domain measurement, which may affect the efficiency of the algorithm. Thirdly, the added disturbance needs to be both small enough and large enough (to stimulate a response), but the system after the disturbance is added is not the original system after all. The stability of the original system does not mean that the system after the disturbance is added is stable. Blindly carrying out time domain frequency scanning without theoretical analysis has certain safety and stability risks. In addition, the need for a dedicated frequency scanning device for prototype experiments will also increase the analysis cost, which needs to be solved urgently. Summary of the invention

[0005] The present invention provides a frequency scanning method, device and equipment for power system equipment to solve the problems of being unfavorable to focusing on the dominant component, affecting the efficiency of the algorithm and the potential safety hazards of time domain frequency scanning caused by the dynamic influence of PWM in the time domain implementation process, and improve the interpretability and applicability of the method.

[0006] A first aspect of the present invention provides a frequency scanning method for power system equipment, the method comprising: establishing a frequency domain steady-state model for a frequency scanning process of a power electronic device, and determining a frequency scanning range; determining an initial scanning frequency based on the frequency scanning range, and based on the initial scanning frequency, extracting a nonlinear equation corresponding to the variable to be determined from the frequency domain steady-state model according to the variable to be determined; iteratively solving the nonlinear equation using the Newton-Raphson method, and when the solution result meets the initial value reselection condition, determining the initial value based on a preset initial value reset strategy, and re-executing the step of iteratively solving the nonlinear equation using the Newton-Raphson method based on the initial value, until the new solution result does not meet the initial value reselection condition.

[0007] Furthermore, in some embodiments, the establishment of a frequency domain steady-state model for the frequency scanning process of a power electronic device includes: determining the time domain equations of multiple frequency components and the number of truncation of the multiples of the dominant frequency component; based on the time domain equations of the multiple frequency components, extracting the Fourier coefficients of each time domain signal, and obtaining the frequency domain steady-state model according to the extraction results and the number of truncation.

[0008] Furthermore, in some embodiments, the preset initial value reset strategy is: for the frequency scanning process of the same disturbance frequency, the frequency scanning result with a smaller disturbance amplitude is used as the initial value of the frequency scanning with a larger disturbance amplitude; for the frequency scanning process of the same disturbance amplitude, the frequency scanning result with the frequency closest to the target frequency is used as the initial value of the frequency scanning of the target frequency.

[0009] Furthermore, in some embodiments, after the nonlinear equation is iteratively solved using the Newton-Raphson method, it also includes: if the solution result does not meet the re-initial value condition, then based on the frequency scanning range, determining the next scanning frequency until the dynamic characteristics of different frequencies within the frequency scanning range are obtained.

[0010] The frequency scanning method of the power system equipment provided by the embodiment of the present invention is based on the harmonic state space theory, and uses the specific mathematical operation results of the nonlinear system under minimal disturbance in the frequency domain to approximate the frequency response of the strict time domain linearization model. The problem of the dynamic influence of PWM in the time domain implementation process, which is not conducive to focusing on the dominant component, affects the efficiency of the algorithm, and has safety hazards in the time domain frequency scanning, is solved. The interpretability and applicability of the method are improved.

[0011] A second aspect of the present invention provides a frequency scanning device for power system equipment, wherein the device includes: a generation module, used to establish a frequency domain steady-state model for the frequency scanning process of the power electronic device, and determine the frequency scanning range; an extraction module, used to determine the initial scanning frequency based on the frequency scanning range, and based on the initial scanning frequency, extract the nonlinear equation corresponding to the variable to be determined from the frequency domain steady-state model according to the variable to be determined; a calculation module, used to iteratively solve the nonlinear equation using the Newton-Raphson method, and when the solution result meets the initial value reselection condition, determine the initial value based on a preset initial value reset strategy, and re-execute the step of iteratively solving the nonlinear equation using the Newton-Raphson method based on the initial value, until the new solution result does not meet the initial value reselection condition.

[0012] Furthermore, in some embodiments, the generation module is specifically used to: determine the time domain equations of multiple frequency components and the truncation times of the multiples of the dominant frequency component; extract the Fourier coefficients of each time domain signal based on the time domain equations of the multiple frequency components, and obtain the frequency domain steady-state model based on the extraction results and the truncation times.

[0013] Furthermore, in some embodiments, the calculation module is specifically used to: for the frequency scanning process of the same disturbance frequency, use the frequency scanning result with a smaller disturbance amplitude as the initial value of the frequency scanning with a larger disturbance amplitude; for the frequency scanning process of the same disturbance amplitude, use the frequency scanning result of the frequency closest to the target frequency as the initial value of the frequency scanning of the target frequency.

[0014] Furthermore, in some embodiments, after the nonlinear equation is iteratively solved using the Newton-Raphson method, it also includes: if the solution result does not meet the re-initial value condition, then based on the frequency scanning range, determining the next scanning frequency until the dynamic characteristics of different frequencies within the frequency scanning range are obtained.

[0015] The frequency scanning device of the power system equipment provided by the embodiment of the present invention, based on the harmonic state space theory, uses the specific mathematical operation results of the nonlinear system under minimal disturbance in the frequency domain to approximate the frequency response of the strict time domain linearization model. The problem of the disadvantage of focusing on the dominant component caused by the dynamic influence of PWM in the time domain implementation process, the influence on the efficiency of the algorithm, and the potential safety hazards of time domain frequency scanning are solved. The interpretability and applicability of the method are improved.

[0016] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0018] Figure 1 A flow chart of a frequency scanning method for power system equipment according to an embodiment of the present invention;

[0019] Figure 2 A schematic diagram of the structure of a three-phase converter grid-connected system according to a specific embodiment of the present invention;

[0020] Figure 3 A schematic diagram of a frequency scanning result of a power system equipment provided according to a specific embodiment of the present invention;

[0021] Figure 4 A flow chart of a frequency scanning method for a force system device according to a specific embodiment of the present invention;

[0022] Figure 5 A block diagram of a frequency scanning device for power system equipment according to an embodiment of the present invention is provided. DETAILED DESCRIPTION

[0023] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0024] The frequency scanning method, device and equipment of the power system equipment of the embodiment of the present invention are described below with reference to the accompanying drawings. In view of the problems mentioned in the above background technology, such as the dynamic influence of PWM in the time domain implementation process is not conducive to focusing on the dominant component, affecting the efficiency of the algorithm, and the potential safety hazards of time domain frequency scanning, the present invention provides a frequency scanning method for power system equipment. Based on the harmonic state space theory, the specific mathematical operation results of the nonlinear system under minimal disturbance are used in the frequency domain to approximate the frequency response of a strict time domain linearization model. The problem that the dynamic influence of PWM in the time domain implementation process is not conducive to focusing on the dominant component, affecting the efficiency of the algorithm, and the potential safety hazards of time domain frequency scanning are solved. The interpretability and applicability of the method are improved.

[0025] Specifically, Figure 1 The present invention provides a flowchart of a frequency scanning method for power system equipment according to an embodiment of the present invention.

[0026] like Figure 1 As shown, the frequency scanning method of the power system equipment includes the following steps:

[0027] In step S101 , a frequency domain steady-state model for a frequency scanning process of a power electronic device is established, and a frequency scanning range is determined.

[0028] Furthermore, in some embodiments, a frequency domain steady-state model for the frequency scanning process of a power electronic device is established, including: determining the time domain equations of multiple frequency components and the number of truncation of the multiples of the dominant frequency component; based on the time domain equations of the multiple frequency components, extracting the Fourier coefficients of each time domain signal, and obtaining the frequency domain steady-state model according to the extraction results and the number of truncation.

[0029] It should be noted that the embodiments of the present invention adopt a frequency domain steady-state modeling method for multiple power electronic converters and their control loops. First, the time domain equations of the three frequency components are listed, and then the Fourier coefficients of each time domain signal are extracted to list the frequency domain model. In the modeling, it is necessary to set the number of truncation for the multiples of the dominant frequency component. Generally, setting the nth order truncation can ensure the calculation accuracy of the (n-1)th order frequency component.

[0030] In order to enable relevant technical personnel in the art to better understand the frequency scanning method of power system equipment in an embodiment of the present invention, a detailed description will be given below in conjunction with specific embodiments.

[0031] Figure 2 The diagram is a structural diagram of a three-phase converter grid-connected system according to a specific embodiment of the present invention.

[0032] like Figure 2 As shown, in the three-phase converter grid-connected system, assuming that a disturbance frequency is injected into the AC side, there are dominant first-order disturbance frequency components on the AC and DC sides. According to the frequency scanning process, there are zero-order, second-order, and third-order disturbance frequency components on the DC side at the same time, but there is a dominant disturbance frequency difference of the fundamental frequency between the AC and DC components. Therefore, for any time domain signal g(t) of the frequency scanning method for the power system equipment of the embodiment of the present invention, its frequency domain corresponds to a vector g composed of the time domain Fourier coefficients g<·>:

[0033] g=[g -1 ,g 0 ,g 1 ] [3×(2×2N+1)]×1 T (1)

[0034] g k =[0 N×1 ,g <k-np> ,…,g <k-p> ,

[0035] g <k>,g<k+p> ,…,g<k+Np> ,0 N×1 ] (2×2N+1)×1 T (2)

[0036] Among them, g<·> is the time domain Fourier coefficient, g is the vector composed of the time domain Fourier coefficient g<·>, g k is the vector component composed of the time-domain Fourier coefficients g<·>.

[0037] In step S102, an initial scanning frequency is determined based on the frequency scanning range, and based on the initial scanning frequency, a nonlinear equation corresponding to the variable to be determined is extracted from a frequency domain steady-state model according to the variable to be determined.

[0038] Among them, one process of frequency scanning is to add a harmonic voltage source of a specific frequency to the system, measure the amplitude-phase of the harmonic current source of the specific frequency, and then perform algebraic operations. In the proposed frequency realization algorithm of the frequency scanning process, the disturbance frequency can be regarded as two types of systems parallel to the dominant frequency of the inverter grid-connected system. The injected voltage disturbance amplitude is set to a fixed value as small as possible, and is combined with the dominant system frequency. After solving the nonlinear equation (such as using the Newton-Raphson method iteration), a specific component is selected from the calculation result for division to obtain the commonly used impedance frequency response of the specific frequency. The disturbance frequency can be generalized from a single frequency to obtain a wide-band impedance frequency response. The results obtained by this process can be regarded as an approximation of the nonlinear system and can be directly used for stability analysis.

[0039] Furthermore, the nonlinear equations based on the harmonic state space theory characterized by harmonic balance can be extracted from the following frequency domain expressions.

[0040] Specifically, for the three-phase converter main circuit, there is the following expression:

[0041]

[0042] 1.5T(m a )i a =T(i load )-N(1 / sC dc ) dc (4)

[0043] Furthermore, for the outer loop control, there is the following expression:

[0044]

[0045] Furthermore, for the inner loop control of the phase-locked loop, there is the following expression:

[0046] -2N(G pll )T[u ta +N(Z g )i a ]sin(θ)=θ (7)

[0047] Furthermore, for the d and q axis current inner loop control, there are the following expressions:

[0048]

[0049] Therefore, the nonlinear equations corresponding to the variables to be solved can be extracted from the frequency domain steady-state model, which is convenient for subsequent iterative solutions.

[0050] In step S103, the Newton-Raphson method is used to iteratively solve the nonlinear equation, and when the solution result meets the condition for reselecting the initial value, the initial value is determined based on a preset initial value reset strategy, and the step of iteratively solving the nonlinear equation using the Newton-Raphson method is re-executed based on the initial value until the new solution result does not meet the condition for reselecting the initial value.

[0051] Among them, the embodiment of the present invention relies on solving nonlinear equations, so the initial value of the iterative algorithm is very important. Ideally, since a harmonic disturbance is added, the steady-state solution of the system before the disturbance is injected can be used as the initial value of the frequency scanning process algorithm, that is, each order harmonic is directly set to 0.

[0052] Specifically, when solving the problem, from m a ,u dc ,i a , and θ respectively select the same number of states and unknowns, and extract the same number of nonlinear equations as the unknowns from the matrix expressions of (3), (4), (5), (6), (7), (8) and (9), so that the unknowns can be solved by the Newton-Raphson method.

[0053] Furthermore, in some embodiments, the preset initial value reset strategy is: for the frequency scanning process of the same disturbance frequency, the frequency scanning result with a smaller disturbance amplitude is used as the initial value of the frequency scanning with a larger disturbance amplitude; for the frequency scanning process of the same disturbance amplitude, the frequency scanning result with the frequency closest to the target frequency is used as the initial value of the frequency scanning of the target frequency.

[0054] Furthermore, in some embodiments, after the nonlinear equation is iteratively solved using the Newton-Raphson method, it also includes: if the solution result does not meet the re-initial value condition, then based on the frequency scanning range, determining the next scanning frequency until the dynamic characteristics of different frequencies within the frequency scanning range are obtained.

[0055] Among them, if the iteration result of a certain nonlinear equation is not ideal, for the frequency scanning process of the same disturbance frequency, the frequency scanning algorithm with a smaller disturbance amplitude can be used as the initial value of the frequency scanning algorithm with a larger disturbance amplitude; or for the frequency scanning process of the same disturbance amplitude, the frequency scanning result that is sufficiently close to the target frequency can be used as the initial value of the frequency scanning algorithm of the target frequency.

[0056] Furthermore, the solution results of the embodiment of the present invention are as follows: Figure 3 As shown, when the injected disturbance amplitude is small enough, the result of the frequency sweep is very close to the linearized model and can even replace the linearized model; when the disturbance increases, the error of the frequency sweep will also increase.

[0057] In order to enable those skilled in the art to further understand the frequency scanning method of the power system equipment according to the embodiment of the present invention, a description will be given below in conjunction with specific embodiments.

[0058] Figure 4 This is a flow chart of a frequency scanning method for a force system equipment according to a specific embodiment of the present invention.

[0059] like Figure 4 As shown, the frequency scanning frequency domain implementation algorithm includes the following steps:

[0060] In step S401, a frequency domain steady-state model for the frequency scanning process of the power electronic device is established to determine the frequency scanning range;

[0061] In step S402, an initial frequency scanning frequency is selected, variables to be determined are determined, and nonlinear equations having the same number of variables are extracted from a frequency domain steady-state model;

[0062] In step S403, an initial value is set and the Newton-Raphson method is used to iteratively solve:

[0063] In step S404, the formula Z′(jω p )-Z′(j(ω p -ω step )>Z set ) is true, if Z′(jω p )-Z′(j(ω p -ω step )>Z set ) then execute step S405, if Z′(jω p )-Z′(j(ω p -ω step )≤Z set ) then execute step S406;

[0064] In step S405, the frequency response is solved, and it is determined whether it is necessary to reselect the initial value to solve the nonlinear equation according to the solution result.

[0065] In step S406, the above process is extended from the initial scanning frequency to the complete frequency range, forming a loop problem.

[0066] Therefore, the frequency response of a strict time-domain linearization model can be approximated by using the specific mathematical operation results of a nonlinear system under minimal disturbance in the frequency domain. The idea of ​​the embodiment of the present invention can be extended to approximate the frequency response of any transfer function including a closed-loop mode, and is easier to be understood by engineers, which has an important enlightenment effect on broadband oscillation.

[0067] It should also be noted that the frequency scanning method for power system equipment provided in the embodiment of the present invention is programmable, and relevant technical personnel can generalize it to approximate the frequency response of any transfer function that includes a closed-loop mode according to actual conditions, and program to implement frequency scanning of power system equipment.

[0068] The frequency scanning method of the power system equipment provided by the embodiment of the present invention is based on the harmonic state space theory, and uses the specific mathematical operation results of the nonlinear system under minimal disturbance in the frequency domain to approximate the frequency response of the strict time domain linearization model. The problem of the dynamic influence of PWM in the time domain implementation process, which is not conducive to focusing on the dominant component, affects the efficiency of the algorithm, and has safety hazards in the time domain frequency scanning, is solved. The interpretability and applicability of the method are improved.

[0069] Next, the frequency scanning device for power system equipment according to an embodiment of the present invention will be described with reference to the accompanying drawings.

[0070] Figure 5 A block diagram of a frequency scanning device for power system equipment according to an embodiment of the present invention is provided.

[0071] like Figure 5 As shown, the frequency scanning device 10 of the power system equipment includes: a generation module 100, an extraction module 200 and a calculation module 300.

[0072] Among them, the generation module 100 is used to establish a frequency domain steady-state model for the frequency scanning process of the power electronic device and determine the frequency scanning range; the extraction module 200 is used to determine the initial scanning frequency based on the frequency scanning range, and based on the initial scanning frequency, extract the nonlinear equation corresponding to the variable to be solved from the frequency domain steady-state model according to the variable to be solved; the calculation module 300 is used to iteratively solve the nonlinear equation using the Newton-Raphson method, and when the solution result meets the condition for reselecting the initial value, determine the initial value based on the preset initial value reset strategy, and re-execute the steps of iteratively solving the nonlinear equation using the Newton-Raphson method based on the initial value, until the new solution result does not meet the condition for reselecting the initial value.

[0073] Furthermore, in some embodiments, the generation module 100 is specifically used to: determine the time domain equations of multiple frequency components and the number of truncation of the multiples of the dominant frequency component; based on the time domain equations of multiple frequency components, extract the Fourier coefficients of each time domain signal, and obtain the frequency domain steady-state model based on the extraction results and the number of truncation.

[0074] Furthermore, in some embodiments, the calculation module 300 is specifically used to: for the frequency scanning process of the same disturbance frequency, use the frequency scanning result with a smaller disturbance amplitude as the initial value of the frequency scanning with a larger disturbance amplitude; for the frequency scanning process of the same disturbance amplitude, use the frequency scanning result of the frequency closest to the target frequency as the initial value of the frequency scanning of the target frequency.

[0075] Furthermore, in some embodiments, after the nonlinear equation is iteratively solved using the Newton-Raphson method, it also includes: if the solution result does not meet the re-initial value condition, then based on the frequency scanning range, determining the next scanning frequency until the dynamic characteristics of different frequencies within the frequency scanning range are obtained.

[0076] It should be noted that the above explanation of the frequency scanning method embodiment of the power system equipment is also applicable to the frequency scanning device of the power system equipment of this embodiment, and will not be repeated here.

[0077] The frequency scanning device of the power system equipment provided by the embodiment of the present invention, based on the harmonic state space theory, uses the specific mathematical operation results of the nonlinear system under minimal disturbance in the frequency domain to approximate the frequency response of the strict time domain linearization model. The problem of the disadvantage of focusing on the dominant component caused by the dynamic influence of PWM in the time domain implementation process, the influence on the efficiency of the algorithm, and the potential safety hazards of time domain frequency scanning are solved. The interpretability and applicability of the method are improved.

[0078] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0079] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, "N" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0080] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present invention includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present invention belong.

[0081] 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 embodiment, the N 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.

[0082] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.< / k> < / k-p> < / k-np>

Claims

1. A frequency scanning method for power system equipment, characterized in that: The following steps are involved: Establish a frequency domain steady-state model for the frequency scanning process of power electronic devices and determine the frequency scanning range; Based on the frequency scanning range, an initial scanning frequency is determined, and based on the initial scanning frequency, a nonlinear equation corresponding to the variable to be determined is extracted from the frequency domain steady-state model according to the variable to be determined; The nonlinear equation is iteratively solved using the Newton-Raphson method, and when the solution result meets the condition for reselecting the initial value, the initial value is determined based on a preset initial value reset strategy, and the step of iteratively solving the nonlinear equation using the Newton-Raphson method is re-executed based on the initial value until the new solution result does not meet the condition for reselecting the initial value.

2. The method according to claim 1, characterized in that: The establishing of a frequency domain steady-state model for a frequency scanning process of a power electronic device comprises: Determine the time domain equations for multiple frequency components and the cutoff times of the multiples of the dominant frequency component; Based on the time domain equations of the multiple frequency components, the Fourier coefficients of each time domain signal are extracted, and the frequency domain steady-state model is obtained according to the extraction result and the number of truncation times.

3. The method according to claim 1, characterized in that The preset initial value reset strategy is: For the frequency scanning process of the same disturbance frequency, the frequency scanning result with a smaller disturbance amplitude is used as the initial value of the frequency scanning with a larger disturbance amplitude; In the frequency scanning process for the same disturbance amplitude, the frequency scanning result of the frequency closest to the target frequency is used as the initial value of the frequency scanning of the target frequency.

4. The method according to claim 1, characterized in that: After the nonlinear equation is iteratively solved by the Newton-Raphson method, the method further includes: If the solution result does not meet the reselection initial value condition, the next scanning frequency is determined based on the frequency scanning range until the dynamic characteristics of different frequencies within the frequency scanning range are determined.

5. A frequency scanning device for power system equipment, characterized in that: The device comprises: A generation module is used to establish a frequency domain steady-state model for the frequency scanning process of the power electronic device and determine the frequency scanning range; An extraction module, configured to determine an initial scanning frequency based on the frequency scanning range, and extract a nonlinear equation corresponding to the variable to be determined from the frequency domain steady-state model based on the initial scanning frequency and according to the variable to be determined; A calculation module is used to iteratively solve the nonlinear equation using the Newton-Raphson method, and when the solution result meets the condition for reselecting the initial value, determine the initial value based on a preset initial value reset strategy, and re-execute the step of iteratively solving the nonlinear equation using the Newton-Raphson method based on the initial value until the new solution result does not meet the condition for reselecting the initial value.

6. The device according to claim 5, characterized in that The generation module is specifically used for: Determine the time domain equations for multiple frequency components and the cutoff times of the multiples of the dominant frequency component; Based on the time domain equations of the multiple frequency components, the Fourier coefficients of each time domain signal are extracted, and the frequency domain steady-state model is obtained according to the extraction result and the number of truncation times.

7. The device according to claim 5, characterized in that The calculation module is specifically used for: For the frequency scanning process of the same disturbance frequency, the frequency scanning result with a smaller disturbance amplitude is used as the initial value of the frequency scanning with a larger disturbance amplitude; In the frequency scanning process for the same disturbance amplitude, the frequency scanning result of the frequency closest to the target frequency is used as the initial value of the frequency scanning of the target frequency.

8. An electronic device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the frequency scanning method for power system equipment according to any one of claims 1 to 4.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: The program is executed by a processor to implement the frequency scanning method for power system equipment according to any one of claims 1 to 4.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the frequency scanning method for power system equipment according to any one of claims 1 to 4 is implemented.

Images