A method and system for identifying the impedance-dominant control link of a two-level converter

Abstract

This invention belongs to the field of impedance characteristic analysis of two-level converters, specifically involving a method and system for identifying the dominant control link in the impedance characteristics of two-level converters. Addressing the difficulties in accurately characterizing converter impedance characteristics and the unclear role of control links in broadband oscillation scenarios under weak power grids, this invention proposes: decomposing the multi-dimensional interaction transfer matrix between the small-signal modulation voltage and small-signal AC voltage / current signals to distinguish the modulation signal component affected by DC voltage; based on this, a port total admittance model incorporating the coupling characteristics of power frequency and oscillation frequency is constructed. Furthermore, the Woodbury matrix identity is used to decompose the admittance model, selecting key interaction admittance matrices, and identifying the dominant control link affecting impedance characteristics by decomposing the control links of each matrix. This solves the problem of unclear dynamic evolution mechanism of converter impedance under oscillating conditions, providing theoretical support for system stability assessment and oscillation suppression strategy design.

Description

Technical Field

[0001] This invention belongs to the field of impedance characteristic analysis of two-level converters, specifically relating to a method and system for identifying the dominant control link of impedance characteristics in two-level converters. Background Technology

[0002] As new energy development expands into desert and Gobi regions, the broadband oscillation problem caused by the integration of new energy sources into weak power grids is gradually intensifying. In weak grid environments, the interaction between the oscillating current and grid impedance causes an abnormally high amplitude of the oscillating voltage, far exceeding the oscillating current, thus highlighting the importance of voltage fluctuation as a core characteristic of broadband oscillations. Broadband voltage oscillations involve static stability assessment and voltage fluctuation control.

[0003] Two-level converters are key interface devices for grid connection of new energy sources, and their dynamic characteristics are crucial to system stability. Their mathematical modeling involves many complex aspects, including the switching action of power semiconductor devices (such as IGBTs), pulse width modulation (PWM) strategies, coordinate transformations (such as Park transformation), and the dynamic response of phase-locked loops (PLLs).

[0004] DC buses are generally not considered ideal voltage sources, and their dynamic behavior significantly impacts the system's dynamic characteristics over a wide frequency range. Especially under oscillating conditions, the superposition of multiple oscillation frequency components can significantly alter the impedance characteristics of the converter ports, posing a new threat to system stability. However, research on accurately understanding and characterizing converter impedance changes under oscillating scenarios, particularly clarifying the roles of different control elements, remains relatively insufficient. Summary of the Invention

[0005] The purpose of this invention is to provide a method and system for identifying the impedance characteristic-dominant control link of a two-level converter, so as to at least solve or improve the problems in the prior art.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for identifying the impedance-dominant control link of a two-level converter, comprising: The small-signal correlation transfer matrix of the modulation voltage of the two-level converter is decomposed to obtain the small-signal correlation transfer matrix between the small-signal modulation voltage and the small-signal AC voltage and the small-signal AC current respectively; wherein, the small-signal modulation voltage includes a first small-signal modulation voltage affected by the small-signal DC voltage and a second small-signal modulation voltage unaffected by the small-signal DC voltage. Based on the aforementioned interactive transfer matrices, the admittance-related interactive transfer matrices of the two-level converter are decomposed to obtain the small-signal coefficient matrices of AC voltage and the small-signal coefficient matrices of AC current, respectively. Based on the small-signal coefficient matrices of AC voltage and AC current, a total port admittance model characterizing the port characteristics of a two-level converter is constructed. The total port admittance model is decomposed to obtain each interaction admittance matrix; The interaction transfer matrix corresponding to each interaction admittance matrix is ​​decomposed using the Woodbury matrix identity to obtain the decomposition result, and the key interaction admittance is determined based on the decomposition result. Based on the key interactive admittance, the dominant control link affecting impedance characteristics in the key interactive admittance is identified.

[0007] Furthermore, the small-signal correlation transfer matrix of the modulation voltage of the two-level converter is decomposed to obtain the respective transfer matrices between the small-signal modulation voltage and the small-signal AC voltage and AC current vectors. Each transfer matrix includes: The first modulation voltage small signal and the AC voltage small signal vector Interactive transfer matrix containing only power frequency The first modulation voltage small signal and the AC voltage small signal vector The interaction transfer matrix is ​​generated by coupling between a steady-state component containing only the power frequency and a small-signal component containing the oscillation frequency. The first modulation voltage small signal and the AC voltage small signal vector The interaction transfer matrix is ​​generated by coupling a steady-state component containing oscillation frequency with a small-signal component containing only power frequency. The first modulation voltage small signal and the AC voltage small signal vector The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing oscillation frequencies. ; The first modulation voltage small signal and the alternating current small signal vector Interactive transfer matrix containing only power frequency The first modulation voltage small signal and the alternating current small signal vector The interaction transfer matrix is ​​generated by coupling between a steady-state component containing only the power frequency and a small-signal component containing the oscillation frequency. The first modulation voltage small signal and the alternating current small signal vector The interaction transfer matrix is ​​generated by coupling a steady-state component containing oscillation frequency with a small-signal component containing only power frequency. The first modulation voltage small signal and the alternating current small signal vector The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing oscillation frequencies. ; The second modulation voltage small signal and the AC voltage small signal vector Interactive transfer matrix containing only power frequency The second modulation voltage small signal and the AC voltage small signal vector The interaction transfer matrix is ​​generated by coupling between a steady-state component containing only the power frequency and a small-signal component containing the oscillation frequency. The second modulation voltage small signal and the AC voltage small signal vector The interaction transfer matrix is ​​generated by coupling a steady-state component containing oscillation frequency with a small-signal component containing only power frequency. The second modulation voltage small signal and the AC voltage small signal vector The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing oscillation frequencies. ; The second modulation voltage small signal and the alternating current small signal vector Interactive transfer matrix containing only power frequency The second modulation voltage small signal and the AC current small signal vector The interaction transfer matrix is ​​generated by coupling between a steady-state component containing only the power frequency and a small-signal component containing the oscillation frequency. The second modulation voltage small signal and the AC current small signal vector The interaction transfer matrix is ​​generated by coupling a steady-state component containing oscillation frequency with a small-signal component containing only power frequency. The second modulation voltage small signal and the AC current small signal vector The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing oscillation frequencies. .

[0008] Furthermore, based on the aforementioned interaction transfer matrices, the admittance-related interaction transfer matrices of the two-level converter are decomposed to obtain the small-signal coefficient matrices of AC voltage and AC current, respectively. The small-signal coefficient matrices of AC voltage and AC current include: Small-signal coefficient matrix of AC voltage containing only power frequency Small-signal coefficient matrix containing only power frequency AC current. ; The small-signal coefficient matrix of AC voltage generated by coupling only the steady-state component of power frequency and the small-signal component containing the oscillation frequency. ; The small-signal coefficient matrix of alternating current generated by coupling only the steady-state component of the power frequency and the small-signal component containing the oscillation frequency. ; The small-signal coefficient matrix of AC voltage generated by the coupling of steady-state component containing oscillation frequency and small-signal component containing oscillation frequency. ; The small-signal coefficient matrix of alternating current generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing oscillation frequencies. .

[0009] Furthermore, based on the small-signal coefficient matrices of each AC voltage and each AC current, a port total admittance model characterizing the port characteristics of the two-level converter is constructed, wherein the port total admittance model... include:

[0010]

[0011] in, It is a small-signal coefficient matrix containing only power frequency AC current. It is the small-signal coefficient matrix of AC current generated by coupling the steady-state component containing only the power frequency with the small-signal component containing the oscillation frequency; It is the small-signal coefficient matrix of AC current generated by coupling the steady-state component containing the oscillation frequency with the small-signal component containing only the power frequency; This is the small-signal coefficient matrix of the alternating current generated by the coupling of a steady-state component containing an oscillation frequency and a small-signal component containing an oscillation frequency. It is a small-signal coefficient matrix of AC voltage containing only the power frequency. This is the small-signal coefficient matrix of AC voltage generated by coupling between a steady-state component containing only the power frequency and a small-signal component containing the oscillation frequency. This is the small-signal coefficient matrix of AC voltage generated by the coupling of a steady-state component containing an oscillation frequency and a small-signal component containing only the power frequency. This is the small-signal coefficient matrix of the AC voltage generated by the coupling of a steady-state component containing an oscillation frequency and a small-signal component containing an oscillation frequency. for The inverse matrix contains only the interaction transfer matrix related to the power frequency. for The inverse matrix contains the interaction transfer matrix related to the oscillation frequency; This is the small-signal coefficient matrix of alternating current.

[0012] Furthermore, the total port admittance model is decomposed to obtain key interaction admittances, including: Combining the Woodbury matrix identity, and based on the multi-dimensional interactive coupling characteristics of oscillation frequency and power frequency, the port total admittance model of the two-level converter is decomposed, and the key interactive admittance is obtained by screening. The key interactive admittance comprises an interactive admittance matrix generated by coupling a steady-state component containing only power frequency and a small-signal component containing only power frequency. The interactive admittance matrix is ​​generated by coupling a steady-state component containing only the power frequency with a small-signal component containing the oscillation frequency. The interactive admittance matrix generated by the coupling of a steady-state component containing oscillation frequency and a small-signal component containing only power frequency. The interactive admittance matrix generated by the coupling of a steady-state component containing an oscillation frequency and a small-signal component containing an oscillation frequency. .

[0013] Furthermore, the interaction transfer matrix corresponding to each of the aforementioned interaction admittance matrices is decomposed using the Woodbury matrix identity to obtain the decomposition results, including: Interaction Transmission Matrix Split into a part containing only the AC current loop controller And a portion that simultaneously contains an AC current loop controller and a DC voltage loop controller. ; Interaction Transmission Matrix Break it down into parts independent of each controller. It contains both an AC current loop controller and a phase-locked loop controller. Only the phase-locked loop controller portion It contains both an AC current loop controller and a DC voltage loop controller. ; Interaction Transmission Matrix Split into a part containing only the AC current loop controller And a portion that simultaneously contains an AC current loop controller and a DC voltage loop controller. ; Interaction Transmission Matrix Split into a part containing only the AC current loop controller And a portion that simultaneously contains an AC current loop controller and a DC voltage loop controller. ; Interaction Transmission Matrix Depending on the controller, it is divided into parts unrelated to each controller. Only the phase-locked loop controller portion It contains both an AC current loop controller and a phase-locked loop controller. It contains both an AC current loop controller and a DC voltage loop controller. .

[0014] Furthermore, based on the identified key interactive admittances, the dominant control links affecting impedance characteristics in the key interactive admittances are obtained, including: Key Interaction Guides Sorted as:

[0015] The dominant control link is:

[0016]

[0017]

[0018] in, This is the part dominated by the AC current loop controller. The part dominated by the phase-locked loop controller. This is the part dominated by the DC voltage loop controller.

[0019] In a second aspect, the present invention provides a device for identifying the impedance-dominant control link of a two-level converter, comprising: The first splitting module is used to split the modulation voltage small signal related interaction transfer matrix of the two-level converter to obtain the interaction transfer matrix between the modulation voltage small signal and the AC voltage small signal vector and the AC current small signal vector respectively; wherein, the modulation voltage small signal includes a first modulation voltage small signal affected by the DC voltage small signal and a second modulation voltage small signal unaffected by the DC voltage small signal. The second splitting module is used to split the admittance-related interactive transfer matrix of the two-level converter based on each of the interactive transfer matrices, so as to obtain each AC voltage small-signal coefficient matrix and each AC current small-signal coefficient matrix respectively. Admittance construction module is used to construct a total port admittance model that characterizes the port characteristics of a two-level converter based on the small-signal coefficient matrices of each AC voltage and each AC current. The third splitting module is used to split the total port admittance model to obtain each interactive admittance matrix; The fourth splitting module is used to split the interaction transfer matrix corresponding to each of the interaction admittance matrices using the Woodbury matrix identity, obtain the splitting result, and determine the key interaction admittance based on the splitting result. The identification module is used to identify the dominant control link affecting impedance characteristics in the key interactive admittance based on the key interactive admittance.

[0020] In a third aspect, the present invention provides an electronic device including a processor and a memory, the processor being configured to execute a computer program stored in the memory to implement the two-level converter impedance characteristic dominant control link identification method as described above.

[0021] In a fourth aspect, the present invention provides a computer-readable storage medium storing at least one instruction that, when executed by a processor, implements the two-level converter impedance characteristic dominant control link identification method as described above.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention solves the problem mentioned in the background art of accurately characterizing the dynamic changes in the port impedance characteristics of a two-level converter under complex wideband oscillation conditions by splitting the interaction transfer matrix between the modulation voltage small signal and the AC voltage / current small signal vector and constructing a port total admittance model that includes multi-frequency coupling characteristics.

[0023] This invention utilizes the Woodbury matrix identity to screen and decompose key interactive admittances in the total port admittance model, refining the complex interactive admittance matrix according to its contained control links. This allows the invention to clearly identify which control links play a dominant role in the overall port impedance characteristics of the converter at a specific oscillation frequency, solving the problem of relatively insufficient research on the role of different control links in impedance characteristics under oscillation scenarios.

[0024] This invention distinguishes between modulation signals affected by small DC voltage signals and those unaffected from the beginning of modeling, and fully considers this distinction in the subsequent construction of the interactive transfer matrix and admittance model. This enables the model to accurately reflect the significant impact of DC bus dynamics on converter port impedance during system oscillation, thus making up for the shortcomings of traditional models in this regard.

[0025] The identification method and results provided by this invention can provide direct and crucial technical basis and theoretical model support for a deeper understanding of the broadband oscillation mechanism caused by the grid connection of new energy sources under weak grid conditions, accurate assessment of system stability, and targeted design of control strategies to suppress oscillations.

[0026] In summary, the method of this invention solves the core problem raised in the background art: the difficulty in accurately characterizing the impedance characteristic changes of two-level converters and identifying their dominant control links under wide-frequency oscillation conditions. Through model decomposition, key interactive admittance screening, and control link decomposition methods, the depth of understanding of the dynamic characteristics of converters under oscillation scenarios is improved, providing theoretical tools and practical guidance for the stability analysis and oscillation suppression of new energy grid-connected systems. Attached Figure Description

[0027] The accompanying drawings, which form part of this application, 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 This is a flowchart of a method for identifying the dominant control link of a two-level converter based on impedance characteristics, according to an embodiment of the present invention. Figure 2 This is a schematic diagram of the two-level converter topology in an embodiment of the present invention; Figure 3 This is a block diagram of the phase-locked loop control in an embodiment of the present invention; Figure 4 This is a block diagram of the AC current control structure in an embodiment of the present invention; Figure 5 This is a block diagram of the DC voltage control structure in an embodiment of the present invention; Figure 6 This is a schematic diagram showing the impedance comparison in scenario 1 of this invention at an oscillation frequency of 55Hz; Figure 7 This is a schematic diagram showing the impedance comparison in scenario 1 of this invention at an oscillation frequency of 120Hz; Figure 8 This is a schematic diagram showing the impedance comparison in scenario 2 of this invention at an oscillation frequency of 55Hz; Figure 9 This is a schematic diagram showing the impedance comparison in scenario 2 of this invention at an oscillation frequency of 148Hz; Figure 10 This is a schematic diagram showing the impedance comparison in scenario 3 of this embodiment of the invention at an oscillation frequency of 48Hz; Figure 11 This is a schematic diagram showing the impedance comparison in scenario 3 of this embodiment of the invention at an oscillation frequency of 148Hz; Figure 12 This is a schematic diagram illustrating the verification of key interactive impedances and their dominant control links in an embodiment of the present invention. Figure 13 This is a structural block diagram of a two-level converter impedance characteristic dominant control link identification device according to an embodiment of the present invention; Figure 14 This is a structural block diagram of an electronic device according to an embodiment of the present invention. Detailed Implementation

[0028] 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 in this application can be combined with each other.

[0029] 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 to which this application pertains. The terminology used in this invention is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention.

[0030] Example 1 To address the challenge of identifying the VSC impedance characteristics-dominant control link in oscillating scenarios, this invention proposes a method for identifying the VSC impedance characteristics-dominant control link in oscillating scenarios by decomposing and filtering the key interactive admittances affecting the VSC port impedance characteristics using the Woodbury matrix identity. This method accurately reflects the relationship between the presence or absence of oscillation frequency and impedance characteristics. This method effectively depicts the interactive influence between the VSC oscillation frequency and the controller, providing crucial technical support for the oscillation mechanism analysis and stability improvement of new energy access to vulnerable networks.

[0031] like Figure 2 As shown, the two-level converter topology used in this invention includes a DC bus capacitor 1, an IGBT inverter 2, and a smoothing reactor 3. The two ends of the DC bus capacitor 1 are connected to the DC side of the IGBT inverter 2, which consists of a group of 6-pulse IGBT inverter valves. The three-phase output current of the IGBT inverter is supplied by the smoothing reactor 3. , , These are the AC voltages for phases a, b, and c, respectively. , , These are the alternating currents of phases a, b, and c, respectively. , , These are the AC modulation voltages for phases a, b, and c, respectively.

[0032] like Figure 1 As shown, a method for identifying the impedance-dominant control link of a two-level converter includes: S1. Decompose the modulation voltage small signal related interaction transfer matrix of the two-level converter to obtain the interaction transfer matrix between the modulation voltage small signal and the AC voltage small signal vector and the AC current small signal vector respectively; wherein, the modulation voltage small signal includes a first modulation voltage small signal affected by the DC voltage small signal and a second modulation voltage small signal not affected by the DC voltage small signal. In one embodiment, each interaction transfer matrix includes: The first modulation voltage small signal and the AC voltage small signal vector Interactive transfer matrix containing only power frequency The first modulation voltage small signal and the AC voltage small signal vector The interaction transfer matrix is ​​generated by coupling between a steady-state component containing only the power frequency and a small-signal component containing the oscillation frequency. The first modulation voltage small signal and the AC voltage small signal vector The interaction transfer matrix is ​​generated by coupling a steady-state component containing oscillation frequency with a small-signal component containing only power frequency. The first modulation voltage small signal and the AC voltage small signal vector The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing oscillation frequencies. ; The first modulation voltage small signal and the alternating current small signal vector Interactive transfer matrix containing only power frequency The first modulation voltage small signal and the alternating current small signal vector The interaction transfer matrix is ​​generated by coupling between a steady-state component containing only the power frequency and a small-signal component containing the oscillation frequency. The first modulation voltage small signal and the alternating current small signal vector The interaction transfer matrix is ​​generated by coupling a steady-state component containing oscillation frequency with a small-signal component containing only power frequency. The first modulation voltage small signal and the alternating current small signal vector The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing oscillation frequencies. ; The second modulation voltage small signal and the AC voltage small signal vector Interactive transfer matrix containing only power frequency The second modulation voltage small signal and the AC voltage small signal vector The interaction transfer matrix is ​​generated by coupling between a steady-state component containing only the power frequency and a small-signal component containing the oscillation frequency. The second modulation voltage small signal and the AC voltage small signal vector The interaction transfer matrix is ​​generated by coupling a steady-state component containing oscillation frequency with a small-signal component containing only power frequency. The second modulation voltage small signal and the AC voltage small signal vector The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing oscillation frequencies. ; The second modulation voltage small signal and the alternating current small signal vector Interactive transfer matrix containing only power frequency The second modulation voltage small signal and the AC current small signal vector The interaction transfer matrix is ​​generated by coupling between a steady-state component containing only the power frequency and a small-signal component containing the oscillation frequency. The second modulation voltage small signal and the AC current small signal vector The interaction transfer matrix is ​​generated by coupling a steady-state component containing oscillation frequency with a small-signal component containing only power frequency. The second modulation voltage small signal and the AC current small signal vector The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing oscillation frequencies. .

[0033] In one embodiment, the modulation voltage small-signal correlation interaction transfer matrix is ​​split, including: Step S101, modulate the small signal of the voltage. Decomposed into small signals subject to DC voltage Small signal of modulation voltage affected and small signals unaffected by DC voltage Small signal of modulation voltage affected ; (1) In the formula, For PWM gain, Let a be the steady-state vector of the phase a AC modulation signal. It is a small-signal vector of DC voltage. The steady-state vector of DC voltage. This is an AC modulation signal of phase a; (2) In the formula, for Small-signal vector of AC voltage in phase a Interaction and transfer matrix between them for Small-signal vector of phase a alternating current Interaction and transfer matrix between them for Small-signal vector of AC voltage in phase a Interaction and transfer matrix between them for Small-signal vector of phase a alternating current Interaction and transfer matrix; Step S102, received Small signal of modulation voltage affected Small-signal vector of AC voltage in phase a a-phase AC current small-signal vector Interaction transfer matrix It can be broken down into: (3) In the formula, for Small-signal vector of AC voltage in phase a The space contains only the power frequency interactive transmission matrix. for and The interaction transfer matrix is ​​generated by coupling between a steady-state component containing only the power frequency and a small-signal component containing the oscillation frequency. for and The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing only power frequency. for and The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing oscillation frequencies. Let a be the steady-state vector of the phase a AC modulation signal. The steady-state vector of the a-phase AC modulation signal containing only the power frequency. Let be the steady-state vector of the a-phase AC modulation signal containing the oscillation frequency. for and Interaction and transfer matrix between them for and The space contains only the power frequency interactive transmission matrix. for and The three interleaved transfer matrices, which contain oscillation frequencies, are expressed in detail as follows: (4) In the formula, This is the DC bus capacitance admittance matrix. This is the DC bus capacitance admittance matrix containing only the power frequency component. The steady-state vector of DC current. , , These are the steady-state vectors of the AC currents in phases a, b, and c, respectively. The steady-state vector of DC current containing only the power frequency component. It is a steady-state vector of DC voltage containing only the power frequency component. , , These are the steady-state vectors of AC current containing only the power frequency in phases a, b, and c, respectively. The phase sequence coefficient matrix of the small signal vector. This is the phase sequence coefficient matrix of a small-signal vector that is only related to the power frequency. The superscript * indicates the conjugate of the matrix. (5) In the formula, for Small-signal vector of phase a alternating current The space contains only the power frequency interactive transmission matrix. for and The interaction transfer matrix is ​​generated by coupling between a steady-state component containing only the power frequency and a small-signal component containing the oscillation frequency. for and The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing only power frequency. for and The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing oscillation frequencies. for and The space contains only the power frequency interactive transmission matrix. for and Interactive transfer matrix containing oscillation frequency; Step S103, not affected Small signal of modulation voltage affected Small-signal vector of AC voltage in phase a a-phase AC current small-signal vector Interaction transfer matrix It can be broken down into: (6) In the formula, for and The space contains only the power frequency interactive transmission matrix. for and The interaction transfer matrix is ​​generated by coupling between a steady-state component containing only the power frequency and a small-signal component containing the oscillation frequency. for and The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing only power frequency. for and The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing oscillation frequencies. The steady-state vector of DC voltage containing the oscillation frequency. for and Interaction and transfer matrix between them for and The space contains only the power frequency interactive transmission matrix. for and The interaction transfer matrix is ​​generated by coupling between a steady-state component containing only the power frequency and a small-signal component containing the oscillation frequency. for and The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing only power frequency. for and The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing oscillation frequencies. for and Interaction and transfer matrix between them for and The space contains only the power frequency interactive transmission matrix. for and The interaction transfer matrix is ​​generated by coupling between a steady-state component containing only the power frequency and a small-signal component containing the oscillation frequency. for and The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing only power frequency. for and The interaction transfer matrix generated by the coupling of a steady-state component containing an oscillating frequency and a small-signal component containing an oscillating frequency is expressed in detail as follows: (7) In the formula, For the small signal d-axis component of the AC modulation signal and Interaction and transfer matrix between them for Small-signal vector of AC voltage in phase a The space contains only the power frequency interactive transmission matrix. for and The interaction transfer matrix is ​​generated by coupling between a steady-state component containing only the power frequency and a small-signal component containing the oscillation frequency. for and The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing only power frequency. for and The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing oscillation frequencies. The decoupling coefficient is the AC current control coefficient. The total phase-locked loop (PLL) interactive transfer matrix, This is a phase-locked loop interactive transfer matrix containing only power frequency signals. The phase-locked loop (PLL) interactive transfer matrix contains the oscillation frequency. , These are the d-axis and q-axis components of the steady-state AC modulation signal, respectively. for and The space contains only the power frequency interactive transmission matrix. for and The interaction transfer matrix is ​​generated by coupling between a steady-state component containing only the power frequency and a small-signal component containing the oscillation frequency. for and The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing only power frequency. for and The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing oscillation frequencies. for Small-signal vector of AC voltage in phase a The space contains only the power frequency interactive transmission matrix. for and The interaction transfer matrix is ​​generated by coupling between a steady-state component containing only the power frequency and a small-signal component containing the oscillation frequency. for and The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing only power frequency. for and The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing oscillation frequencies. cosine function Steady-state vector, The sine function Steady-state vector, A cosine function containing only the power frequency Steady-state vector, A sine function containing only the power frequency Steady-state vector, A cosine function containing an oscillation frequency Steady-state vector, A sine function containing an oscillation frequency Steady-state vector; (8) In the formula, for and The space contains only the power frequency interactive transmission matrix. for and The interaction transfer matrix is ​​generated by coupling between a steady-state component containing only the power frequency and a small-signal component containing the oscillation frequency. for and The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing only power frequency. for and The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing oscillation frequencies. for and Interaction and transfer matrix between them for and The space contains only the power frequency interactive transmission matrix. for and The interaction transfer matrix is ​​generated by coupling between a steady-state component containing only the power frequency and a small-signal component containing the oscillation frequency. for and The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing only power frequency. for and The interaction transfer matrix generated by the coupling of a steady-state component containing an oscillating frequency and a small-signal component containing an oscillating frequency is expressed in detail as follows: (9) In the formula, for and Interaction and transfer matrix between them for and The space contains only the power frequency interactive transmission matrix. for and The interaction transfer matrix is ​​generated by coupling between a steady-state component containing only the power frequency and a small-signal component containing the oscillation frequency. for and The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing only power frequency. for and The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing oscillation frequencies. For the q-axis component of the AC modulation signal Small-signal vector of phase a alternating current Interaction and transfer matrix between them for Small-signal vector of phase a alternating current The space contains only the power frequency interactive transmission matrix. for and The interaction transfer matrix is ​​generated by coupling between a steady-state component containing only the power frequency and a small-signal component containing the oscillation frequency. for and The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing only power frequency. for and The interaction transfer matrix is ​​generated by the coupling of steady-state components with oscillation frequencies and small-signal components with oscillation frequencies.

[0034] S2. Based on the aforementioned interactive transfer matrices, the admittance-related interactive transfer matrices of the two-level converter are decomposed to obtain the small-signal coefficient matrices of AC voltage and the small-signal coefficient matrices of AC current respectively. In one embodiment, each AC voltage small-signal coefficient matrix and each AC current small-signal coefficient matrix includes: Small-signal coefficient matrix of AC voltage containing only power frequency Small-signal coefficient matrix containing only power frequency AC current. ; The small-signal coefficient matrix of AC voltage generated by coupling only the steady-state component of power frequency and the small-signal component containing the oscillation frequency. ; The small-signal coefficient matrix of alternating current generated by coupling only the steady-state component of the power frequency and the small-signal component containing the oscillation frequency. ; The small-signal coefficient matrix of AC voltage generated by the coupling of steady-state component containing oscillation frequency and small-signal component containing oscillation frequency. ; The small-signal coefficient matrix of alternating current generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing oscillation frequencies. .

[0035] In one embodiment, the admittance-related interaction transfer matrix is ​​split, including: (10) In the formula, It is a small-signal coefficient matrix of AC voltage containing only the power frequency. It is a small-signal coefficient matrix containing only power frequency AC current. An identity matrix that is only related to the power frequency. For AC filter inductance containing only power frequency in a small-signal frequency sequence; (11) In the formula, This is the small-signal coefficient matrix of AC voltage generated by coupling between a steady-state component containing only the power frequency and a small-signal component containing the oscillation frequency. It is the small-signal coefficient matrix of AC current generated by coupling the steady-state component containing only the power frequency with the small-signal component containing the oscillation frequency; (12) In the formula, This is the small-signal coefficient matrix of AC voltage generated by the coupling of a steady-state component containing an oscillation frequency and a small-signal component containing only the power frequency. It is the small-signal coefficient matrix of AC current generated by coupling the steady-state component containing the oscillation frequency with the small-signal component containing only the power frequency; (13) In the formula, This is the small-signal coefficient matrix of the AC voltage generated by the coupling of a steady-state component containing an oscillation frequency and a small-signal component containing an oscillation frequency. This is the small-signal coefficient matrix of the alternating current generated by the coupling of a steady-state component containing an oscillation frequency and a small-signal component containing an oscillation frequency. The identity matrix is ​​related to the oscillation frequency. This is the impedance matrix of an AC filter inductor containing an oscillation frequency under a small-signal frequency sequence. This is the DC bus capacitance admittance matrix under small-signal frequency sequences; Therefore, we get: (14) In the formula, This is the small-signal coefficient matrix of AC voltage. This is the small-signal coefficient matrix of alternating current.

[0036] S3. Based on the small-signal coefficient matrices of the AC voltage and the small-signal coefficient matrices of the AC current, construct a total port admittance model that characterizes the port characteristics of the two-level converter; In one embodiment, a total port admittance model characterizing the port characteristics of a two-level converter is constructed. Its parsing expression is: (15) in: (16) in, It is a small-signal coefficient matrix containing only power frequency AC current. It is the small-signal coefficient matrix of AC current generated by coupling the steady-state component containing only the power frequency with the small-signal component containing the oscillation frequency; It is the small-signal coefficient matrix of AC current generated by coupling the steady-state component containing the oscillation frequency with the small-signal component containing only the power frequency; This is the small-signal coefficient matrix of the alternating current generated by the coupling of a steady-state component containing an oscillation frequency and a small-signal component containing an oscillation frequency. It is a small-signal coefficient matrix of AC voltage containing only the power frequency. This is the small-signal coefficient matrix of AC voltage generated by coupling between a steady-state component containing only the power frequency and a small-signal component containing the oscillation frequency. This is the small-signal coefficient matrix of AC voltage generated by the coupling of a steady-state component containing an oscillation frequency and a small-signal component containing only the power frequency. This is the small-signal coefficient matrix of the AC voltage generated by the coupling of a steady-state component containing an oscillation frequency and a small-signal component containing an oscillation frequency. for The inverse matrix contains only the interaction transfer matrix related to the power frequency. for The inverse matrix contains the interaction transfer matrix related to the oscillation frequency; This is the small-signal coefficient matrix of alternating current.

[0037] S4. Decompose the total port admittance model to obtain each interactive admittance matrix; In one embodiment, the total port admittance model is decomposed to obtain key interaction admittances, including: Combining the Woodbury matrix identity, and based on the multi-dimensional interactive coupling characteristics of oscillation frequency and power frequency, the port total admittance model of the two-level converter is decomposed, and the key interactive admittance is obtained by screening. The key interactive admittance comprises an interactive admittance matrix generated by coupling a steady-state component containing only power frequency and a small-signal component containing only power frequency. The interactive admittance matrix is ​​generated by coupling a steady-state component containing only the power frequency with a small-signal component containing the oscillation frequency. The interactive admittance matrix generated by the coupling of a steady-state component containing oscillation frequency and a small-signal component containing only power frequency. The interactive admittance matrix generated by the coupling of a steady-state component containing an oscillation frequency and a small-signal component containing an oscillation frequency. .

[0038] In one embodiment, the port admittance of the two-level converter is decomposed based on the Woodbury matrix identity and the multi-dimensional interactive coupling characteristics of the oscillation frequency and the power frequency, and key interactive admittances are selected. Both the steady-state component and the small-signal component can be decomposed into two parts: one containing only the power frequency and the other containing the oscillation frequency. Therefore, the total admittance can be decomposed into the following four parts: (17) In the formula, The interaction admittance matrix is ​​generated by coupling the steady-state component containing only power frequency with the small-signal component containing only power frequency. The interaction admittance matrix is ​​generated by coupling a steady-state component containing only the power frequency with a small-signal component containing the oscillation frequency. The interaction admittance matrix is ​​generated by the coupling of a steady-state component containing an oscillation frequency and a small-signal component containing only the power frequency. It is the interactive admittance matrix generated by the coupling of a steady-state component containing an oscillation frequency and a small-signal component containing an oscillation frequency; (18) In the formula, The admittance of the filter capacitor containing only the power frequency in a small-signal frequency sequence; (19) (20) (twenty one) In the formula, This is the admittance matrix of the filter capacitor containing the oscillation frequency in a small-signal frequency sequence. It is an identity matrix.

[0039] S5. The interaction transfer matrix corresponding to each interaction admittance matrix is ​​decomposed using the Woodbury matrix identity to obtain the decomposition result, and the key interaction admittance is determined based on the decomposition result. In one embodiment, the interaction transfer matrix corresponding to each of the interaction admittance matrices is decomposed using the Woodbury matrix identity to obtain the decomposition result, including: Interaction Transmission Matrix Split into a part containing only the AC current loop controller And a portion that simultaneously contains an AC current loop controller and a DC voltage loop controller. ; Interaction Transmission Matrix Break it down into parts independent of each controller. It contains both an AC current loop controller and a phase-locked loop controller. Only the phase-locked loop controller portion It contains both an AC current loop controller and a DC voltage loop controller. ; Interaction Transmission Matrix Split into a part containing only the AC current loop controller And a portion that simultaneously contains an AC current loop controller and a DC voltage loop controller. ; Interaction Transmission Matrix Split into a part containing only the AC current loop controller And a portion that simultaneously contains an AC current loop controller and a DC voltage loop controller. ; Interaction Transmission Matrix Depending on the controller, it is divided into parts unrelated to each controller. Only the phase-locked loop controller portion It contains both an AC current loop controller and a phase-locked loop controller. It contains both an AC current loop controller and a DC voltage loop controller. .

[0040] In one embodiment, the key interaction admittance control link is decomposed, including: Step S501, in the interactive transfer matrix It contains two types of controllers: AC current loop controller and DC voltage loop controller, therefore it can be divided into... and Two parts, of which for It only contains the part of the AC current loop controller. for It contains both AC current loop controller and DC voltage loop controller components, and their detailed analytical expressions are as follows: (twenty two) In the formula, For an AC current controller containing only power frequency, the transfer function is... , These are the d-axis and q-axis components of the small-signal alternating current, respectively. , Small-signal vector of phase a alternating current The interaction transfer matrix containing only power frequency is expressed as follows: (twenty three) In the formula, , These are cosine functions containing only the power frequency. , Steady-state vector, , These are sine functions containing only the power frequency. , The steady-state vector, It is a phase sequence coefficient matrix containing only small-signal vectors of power frequency; Step S502, Interactive transfer matrix The expression that is further elaborated is as follows: (twenty four) In the formula, A cosine function containing an oscillation frequency The steady-state vector, A sine function containing an oscillation frequency The steady-state vector, The transformation matrix is ​​for a modulation signal containing only the power frequency. The transformation matrix of the modulated signal containing the oscillation frequency, d-axis component of AC modulated signal and The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing oscillation frequencies. d-axis component of AC modulated signal and The interaction transfer matrix is ​​generated by coupling between a steady-state component containing only the power frequency and a small-signal component containing the oscillation frequency. For the q-axis component of the AC modulation signal and The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing oscillation frequencies. For the q-axis component of the AC modulation signal and The interaction transfer matrix is ​​generated by coupling between a steady-state component containing only the power frequency and a small-signal component containing the oscillation frequency. The phase-locked loop interactive transfer matrix contains the oscillation frequency; It contains an AC current controller and a phase-locked loop controller, and can be divided into the following two parts. (25) In the formula, for It contains both an AC current control loop and a phase-locked loop controller. for It only contains the part of the phase-locked loop controller. For the small-signal d-axis component of alternating current and The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing oscillation frequencies. For the small-signal d-axis component of alternating current and The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing only power frequency. The transfer function for an AC current controller containing an oscillating frequency. For the small-signal q-axis component of alternating current and The interaction transfer matrix generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing oscillation frequencies; Similarly, It can be divided into the following two parts (26) In the formula, for It contains both an AC current control loop and a phase-locked loop controller. for It only contains the part of the phase-locked loop controller. For the small-signal d-axis component of alternating current and The interaction transfer matrix is ​​generated by coupling between a steady-state component containing only the power frequency and a small-signal component containing the oscillation frequency. For the small-signal d-axis component of alternating current Small-signal vector of AC voltage in phase a The space contains only the power frequency interactive transmission matrix. For the small-signal q-axis component of alternating current and The interaction transfer matrix is ​​generated by coupling between a steady-state component containing only the power frequency and a small-signal component containing the oscillation frequency. It can be divided into the following two parts (27) In the formula, for It contains both an AC current control loop and a phase-locked loop controller. for It only contains the part of the phase-locked loop controller. For the small-signal q-axis component of alternating current and The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing oscillation frequencies. For the small-signal q-axis component of alternating current and The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing only power frequency. For the small-signal d-axis component of alternating current and The interaction transfer matrix generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing oscillation frequencies; It can be divided into the following two parts (28) In the formula, for It contains both an AC current control loop and a phase-locked loop controller. for It only contains the part of the phase-locked loop controller. For the small-signal q-axis component of alternating current and The interaction transfer matrix is ​​generated by coupling between a steady-state component containing only the power frequency and a small-signal component containing the oscillation frequency. For the small-signal q-axis component of alternating current Small-signal vector of AC voltage in phase a The space contains only the power frequency interactive transmission matrix. For the small-signal d-axis component of alternating current and The interaction transfer matrix is ​​generated by coupling between a steady-state component containing only the power frequency and a small-signal component containing the oscillation frequency. Combining equations (21) to (25), the interactive transfer matrix can be... Split into (29) In the formula, for The part that is unrelated to each controller for It contains both an AC current loop controller and a phase-locked loop controller. for It only contains the part of the phase-locked loop controller. for It contains both AC current loop controller and DC voltage loop controller components, and the detailed expressions for each term are as follows: (30) (31) (32) (33) Step S503, in the interactive transfer matrix It contains two types of controllers: AC current loop controller and DC voltage loop controller, therefore it can be divided into... and Two parts, of which for It only contains the part of the AC current loop controller. for It contains both AC current loop controller and DC voltage loop controller components, and their detailed analytical expressions are as follows: (34) In the formula, for The inverse matrix contains only the portion related to the AC current loop controller. for The inverse matrix contains portions of both the AC current loop controller and the DC voltage loop controller, whose expressions are as follows: (35) In the formula, The impedance of the AC filter inductor under small signal frequency sequence; Step S504, Interactive transfer matrix The expression that is further elaborated is as follows (36) In the formula, For the small-signal q-axis component of alternating current Small-signal vector of AC voltage in phase a Interaction and transfer matrix between them For the small-signal d-axis component of alternating current Small-signal vector of AC voltage in phase a Interaction and transfer matrix between them The total phase-locked loop (PLL) interactive transfer matrix, The transformation matrix of the modulation signal; Depending on the controller, it can be divided into (37) In the formula, for The part that is unrelated to each controller for It only contains the part of the phase-locked loop controller. for It contains both an AC current loop controller and a phase-locked loop controller. for It contains both AC current loop controller and DC voltage loop controller components, and the detailed expressions for each term are as follows: (38) (39) (40) (41) S6. Identify the dominant control link affecting impedance characteristics in the key interactive admittance based on the key interactive admittance.

[0041] In one embodiment, the dominant control link affecting impedance characteristics in the critical interactive admittance is identified; based on step S5, the critical interactive admittance can be summarized as follows: (42) In the formula, Admitted to key interactions The part dominated by the AC current loop controller. Admitted to key interactions The part dominated by the phase-locked loop controller, Admitted to key interactions The main part dominated by the DC voltage loop controller, with detailed analytical expressions for each item as follows: (43) (44) (45) in, This is the part dominated by the AC current loop controller. The part dominated by the phase-locked loop controller. This is the part dominated by the DC voltage loop controller.

[0042] In this specific application example, the method for identifying the control link dominated by the impedance characteristics of the VSC in an oscillating scenario is verified. The main circuit and control parameters of the two-level converter are shown in Table 1.

[0043] Table 1. Main circuit and control parameters of the two-level converter

[0044] Three oscillation scenarios are set: (1) Scenario 1: AC current loop control bandwidth 200Hz, phase-locked loop control bandwidth 10Hz, DC voltage loop control bandwidth 40Hz; (2) Scenario 2: AC current loop control bandwidth 270Hz, phase-locked loop control bandwidth 10Hz, DC voltage loop control bandwidth 40Hz; (3) Scenario 3: AC current loop control bandwidth 270Hz, phase-locked loop control bandwidth 25Hz, DC voltage loop control bandwidth 40Hz. Following steps S1 to S6, the port impedance analysis results of the two-level converter under three scenarios are established, as shown below. Figure 6-11 As shown. By Figure 6It can be seen that in scenario 1, within the 0-100Hz frequency band, when the oscillation frequency is 55Hz, the critical inter-impedance Z22 has the greatest impact on the impedance characteristics; from Figure 7 It can be seen that in scenario 1, within the frequency range above 100Hz, when the oscillation frequency is 120Hz, the key interactive impedance Z22 has the greatest impact on the impedance characteristics; from Figure 8 It can be seen that in scenario 2, within the 0-100Hz frequency band, when the oscillation frequency is 55Hz, the key interactive impedance Z22 has the greatest impact on the impedance characteristics; from Figure 9 It can be seen that in scenario 2, within the frequency range above 100Hz, when the oscillation frequency is 148Hz, the key interactive impedance Z22 has the greatest impact on the impedance characteristics; from Figure 10 It can be seen that in scenario 3, within the 0-100Hz frequency band, when the oscillation frequency is 48Hz, the critical inter-impedance Z22 has the greatest impact on the impedance characteristics; from Figure 11 It can be seen that in scenario 3, within the frequency range above 100Hz, when the oscillation frequency is 148Hz, the key interactive impedance Z22 has the greatest impact on the impedance characteristics. By comparison, it can be seen that within the 0-100Hz frequency range, the oscillation frequency with the greatest impact on impedance is mainly affected by the phase-locked loop; within the frequency range above 100Hz, the oscillation frequency with the greatest impact on impedance is mainly affected by the current loop.

[0045] Following steps S1 to S6, establish the analytical results of the key interactive impedances and their dominant control links, such as... Figure 12 As shown. By comparison Figure 12 From the amplitude curves of each control link, it can be found that in the 0-100Hz frequency band, the amplitude of the dominant interactive impedance is mainly affected by the DC voltage loop control link, that is, the DC voltage loop is the dominant control link; in the frequency band above 100Hz, the amplitude of the dominant interactive impedance is mainly affected by the AC current loop control link, that is, the current loop is the dominant control link.

[0046] Example 2 like Figure 13 As shown, based on the same inventive concept as the above embodiments, the present invention also provides a two-level converter impedance characteristic dominant control link identification device, comprising: The first splitting module is used to split the modulation voltage small signal related interaction transfer matrix of the two-level converter to obtain the interaction transfer matrix between the modulation voltage small signal and the AC voltage small signal vector and the AC current small signal vector respectively; wherein, the modulation voltage small signal includes a first modulation voltage small signal affected by the DC voltage small signal and a second modulation voltage small signal unaffected by the DC voltage small signal. The second splitting module is used to split the admittance-related interactive transfer matrix of the two-level converter based on each of the interactive transfer matrices, so as to obtain each AC voltage small-signal coefficient matrix and each AC current small-signal coefficient matrix respectively. Admittance construction module is used to construct a total port admittance model that characterizes the port characteristics of a two-level converter based on the small-signal coefficient matrices of each AC voltage and each AC current. The third splitting module is used to split the total port admittance model to obtain each interactive admittance matrix; The fourth splitting module is used to split the interaction transfer matrix corresponding to each of the interaction admittance matrices using the Woodbury matrix identity, obtain the splitting result, and determine the key interaction admittance based on the splitting result. The identification module is used to identify the dominant control link affecting impedance characteristics in the key interactive admittance based on the key interactive admittance.

[0047] Example 3 like Figure 14 As shown, the present invention also provides an electronic device 100 for implementing a method for identifying a two-level converter impedance characteristic dominant control link. 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 at least one processor 102, and at least one communication bus 104.

[0048] The memory 101 can be used to store the computer program 103. The processor 102 implements the steps of the method for identifying the impedance characteristics of a two-level converter dominant control link in Embodiment 1 by running or executing the computer program stored in the memory 101 and calling the data stored in the memory 101.

[0049] The memory 101 may primarily include a program storage area and a data storage area. The program storage area may store the operating system, application programs required for at least one 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, RAM, 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.

[0050] 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. Processor 102 may be a microprocessor or any conventional processor. Processor 102 is the control center of electronic device 100, connecting various parts of electronic device 100 via various interfaces and lines.

[0051] The memory 101 in the electronic device 100 stores multiple instructions to implement a two-level converter impedance characteristic-dominant control link identification method, and the processor 102 can execute multiple instructions to achieve the following: The small-signal correlation transfer matrix of the modulation voltage of the two-level converter is decomposed to obtain the small-signal correlation transfer matrix between the small-signal modulation voltage and the small-signal AC voltage and the small-signal AC current respectively; wherein, the small-signal modulation voltage includes a first small-signal modulation voltage affected by the small-signal DC voltage and a second small-signal modulation voltage unaffected by the small-signal DC voltage. Based on the aforementioned interactive transfer matrices, the admittance-related interactive transfer matrices of the two-level converter are decomposed to obtain the small-signal coefficient matrices of AC voltage and the small-signal coefficient matrices of AC current, respectively. Based on the small-signal coefficient matrices of AC voltage and AC current, a total port admittance model characterizing the port characteristics of a two-level converter is constructed. The total port admittance model is decomposed to obtain each interaction admittance matrix; The interaction transfer matrix corresponding to each interaction admittance matrix is ​​decomposed using the Woodbury matrix identity to obtain the decomposition result, and the key interaction admittance is determined based on the decomposition result. Based on the key interactive admittance, the dominant control link affecting impedance characteristics in the key interactive admittance is identified.

[0052] Example 4 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 of the present invention 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 computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, and read-only memory (ROM).

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0058] 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 method for identifying the impedance-dominant control link of a two-level converter, characterized in that, include: The small-signal correlation transfer matrix of the modulation voltage of the two-level converter is decomposed to obtain the small-signal correlation transfer matrix between the small-signal modulation voltage and the small-signal AC voltage and the small-signal AC current respectively; wherein, the small-signal modulation voltage includes a first small-signal modulation voltage affected by the small-signal DC voltage and a second small-signal modulation voltage unaffected by the small-signal DC voltage. Based on the aforementioned interactive transfer matrices, the admittance-related interactive transfer matrices of the two-level converter are decomposed to obtain the small-signal coefficient matrices of AC voltage and the small-signal coefficient matrices of AC current, respectively. Based on the small-signal coefficient matrices of AC voltage and AC current, a total port admittance model characterizing the port characteristics of a two-level converter is constructed. The total port admittance model is decomposed to obtain each interaction admittance matrix; The interaction transfer matrix corresponding to each interaction admittance matrix is ​​decomposed using the Woodbury matrix identity to obtain the decomposition result, and the key interaction admittance is determined based on the decomposition result. Based on the key interactive admittance, the dominant control link affecting impedance characteristics in the key interactive admittance is identified.

2. The method for identifying the impedance characteristic-dominant control link of a two-level converter according to claim 1, characterized in that, The small-signal correlation transfer matrix of the modulation voltage of the two-level converter is decomposed to obtain the respective transfer matrices between the small-signal modulation voltage and the small-signal AC voltage and AC current vectors. Each transfer matrix includes: The first modulation voltage small signal and the AC voltage small signal vector Interactive transfer matrix containing only power frequency The first modulation voltage small signal and the AC voltage small signal vector The interaction transfer matrix is ​​generated by coupling between a steady-state component containing only the power frequency and a small-signal component containing the oscillation frequency. The first modulation voltage small signal and the AC voltage small signal vector The interaction transfer matrix is ​​generated by coupling a steady-state component containing oscillation frequency with a small-signal component containing only power frequency. The first modulation voltage small signal and the AC voltage small signal vector The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing oscillation frequencies. ; The first modulation voltage small signal and the alternating current small signal vector Interactive transfer matrix containing only power frequency The first modulation voltage small signal and the alternating current small signal vector The interaction transfer matrix is ​​generated by coupling between a steady-state component containing only the power frequency and a small-signal component containing the oscillation frequency. The first modulation voltage small signal and the alternating current small signal vector The interaction transfer matrix is ​​generated by coupling a steady-state component containing oscillation frequency with a small-signal component containing only power frequency. The first modulation voltage small signal and the alternating current small signal vector The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing oscillation frequencies. ; The second modulation voltage small signal and the AC voltage small signal vector Interactive transfer matrix containing only power frequency The second modulation voltage small signal and the AC voltage small signal vector The interaction transfer matrix is ​​generated by coupling between a steady-state component containing only the power frequency and a small-signal component containing the oscillation frequency. The second modulation voltage small signal and the AC voltage small signal vector The interaction transfer matrix is ​​generated by coupling a steady-state component containing oscillation frequency with a small-signal component containing only power frequency. The second modulation voltage small signal and the AC voltage small signal vector The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing oscillation frequencies. ; The second modulation voltage small signal and the alternating current small signal vector Interactive transfer matrix containing only power frequency The second modulation voltage small signal and the AC current small signal vector The interaction transfer matrix is ​​generated by coupling between a steady-state component containing only the power frequency and a small-signal component containing the oscillation frequency. The second modulation voltage small signal and the AC current small signal vector The interaction transfer matrix is ​​generated by coupling a steady-state component containing oscillation frequency with a small-signal component containing only power frequency. The second modulation voltage small signal and the AC current small signal vector The interaction transfer matrix is ​​generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing oscillation frequencies. .

3. The method for identifying the impedance characteristic-dominant control link of a two-level converter according to claim 2, characterized in that, Based on the aforementioned interaction transfer matrices, the admittance-related interaction transfer matrices of the two-level converter are decomposed to obtain the small-signal coefficient matrices of AC voltage and AC current, respectively. The small-signal coefficient matrices of AC voltage and AC current include: Small-signal coefficient matrix of AC voltage containing only power frequency Small-signal coefficient matrix containing only power frequency AC current. ; The small-signal coefficient matrix of AC voltage generated by coupling only the steady-state component of power frequency and the small-signal component containing the oscillation frequency. ; The small-signal coefficient matrix of alternating current generated by coupling only the steady-state component of the power frequency and the small-signal component containing the oscillation frequency. ; The small-signal coefficient matrix of AC voltage generated by the coupling of steady-state component containing oscillation frequency and small-signal component containing oscillation frequency. ; The small-signal coefficient matrix of alternating current generated by the coupling of steady-state components containing oscillation frequencies and small-signal components containing oscillation frequencies. .

4. The method for identifying the impedance characteristic-dominant control link of a two-level converter according to claim 1, characterized in that, Based on the small-signal coefficient matrices of the AC voltage and the small-signal coefficient matrices of the AC current, a port total admittance model characterizing the port characteristics of a two-level converter is constructed. include: in, It is a small-signal coefficient matrix containing only power frequency AC current. It is the small-signal coefficient matrix of AC current generated by coupling the steady-state component containing only the power frequency with the small-signal component containing the oscillation frequency; It is the small-signal coefficient matrix of AC current generated by coupling the steady-state component containing the oscillation frequency with the small-signal component containing only the power frequency; This is the small-signal coefficient matrix of the alternating current generated by the coupling of a steady-state component containing an oscillation frequency and a small-signal component containing an oscillation frequency. It is a small-signal coefficient matrix of AC voltage containing only the power frequency. This is the small-signal coefficient matrix of AC voltage generated by coupling a steady-state component containing only the power frequency with a small-signal component containing the oscillation frequency. This is the small-signal coefficient matrix of AC voltage generated by the coupling of a steady-state component containing an oscillation frequency and a small-signal component containing only the power frequency. This is the small-signal coefficient matrix of the AC voltage generated by the coupling of a steady-state component containing an oscillation frequency and a small-signal component containing an oscillation frequency. for The inverse matrix contains only the interaction transfer matrix related to the power frequency. for The inverse matrix contains the interaction transfer matrix related to the oscillation frequency; This is the small-signal coefficient matrix of alternating current.

5. The method for identifying the impedance characteristic-dominant control link of a two-level converter according to claim 1, characterized in that, The total port admittance model is decomposed to obtain key interaction admittances, including: Combining the Woodbury matrix identity, and based on the multi-dimensional interactive coupling characteristics of oscillation frequency and power frequency, the port total admittance model of the two-level converter is decomposed, and the key interactive admittance is obtained by screening. The key interactive admittance comprises an interactive admittance matrix generated by coupling a steady-state component containing only power frequency and a small-signal component containing only power frequency. The interactive admittance matrix is ​​generated by coupling a steady-state component containing only the power frequency with a small-signal component containing the oscillation frequency. The interactive admittance matrix generated by the coupling of a steady-state component containing oscillation frequency and a small-signal component containing only power frequency. The interactive admittance matrix generated by the coupling of a steady-state component containing an oscillation frequency and a small-signal component containing an oscillation frequency. .

6. The method for identifying the impedance characteristic-dominant control link of a two-level converter according to claim 4, characterized in that, The interaction transfer matrix corresponding to each of the aforementioned interaction admittance matrices is decomposed using the Woodbury matrix identity, yielding the following decomposition results: Interaction Transmission Matrix Split into a part containing only the AC current loop controller And a portion that simultaneously contains an AC current loop controller and a DC voltage loop controller. ; Interaction Transmission Matrix Break it down into parts independent of each controller. It contains both an AC current loop controller and a phase-locked loop controller. Only the phase-locked loop controller portion It contains both an AC current loop controller and a DC voltage loop controller. ; Interaction Transmission Matrix Split into a part containing only the AC current loop controller And a portion that simultaneously contains an AC current loop controller and a DC voltage loop controller. ; Interaction Transmission Matrix Split into a part containing only the AC current loop controller And a portion that simultaneously contains an AC current loop controller and a DC voltage loop controller. ; Interaction Transmission Matrix Depending on the controller, it is divided into parts unrelated to each controller. Only the phase-locked loop controller portion It contains both an AC current loop controller and a phase-locked loop controller. It contains both an AC current loop controller and a DC voltage loop controller. .

7. The method for identifying the impedance characteristic-dominant control link of a two-level converter according to claim 6, characterized in that, Based on the identification of the key interactive admittance, the dominant control links affecting impedance characteristics in the key interactive admittance are obtained, including: Key Interaction Guides Sorted as: The dominant control link is: in, This is the part dominated by the AC current loop controller. The part dominated by the phase-locked loop controller. This is the part dominated by the DC voltage loop controller.

8. A device for identifying the impedance characteristic-dominant control link of a two-level converter, characterized in that, include: The first splitting module is used to split the modulation voltage small signal related interaction transfer matrix of the two-level converter to obtain the interaction transfer matrix between the modulation voltage small signal and the AC voltage small signal vector and the AC current small signal vector respectively; wherein, the modulation voltage small signal includes a first modulation voltage small signal affected by the DC voltage small signal and a second modulation voltage small signal unaffected by the DC voltage small signal. The second splitting module is used to split the admittance-related interactive transfer matrix of the two-level converter based on each of the interactive transfer matrices, so as to obtain each AC voltage small-signal coefficient matrix and each AC current small-signal coefficient matrix respectively. Admittance construction module is used to construct a total port admittance model that characterizes the port characteristics of a two-level converter based on the small-signal coefficient matrices of each AC voltage and each AC current. The third splitting module is used to split the total port admittance model to obtain each interactive admittance matrix; The fourth splitting module is used to split the interaction transfer matrix corresponding to each of the interaction admittance matrices using the Woodbury matrix identity, obtain the splitting results, and determine the key interaction admittances based on the splitting results. The identification module is used to identify the dominant control link affecting impedance characteristics in the key interactive admittance based on the key interactive admittance.

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 two-level converter impedance characteristic dominant control link identification method as described in any one of claims 1 to 7.

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 two-level converter impedance characteristic dominant control link identification method as described in any one of claims 1 to 7.

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