Network construction converter active support control method and device based on frequency voltage coupling

Abstract

The invention discloses a network construction converter active support control method and device based on frequency voltage coupling. Comprising the steps that system parameters and operation condition parameters, used for calculating additional control parameters, of a network construction converter are obtained, and the operation power angle of the network construction converter is calculated according to the power angle between alternating-current power grids and the power angle generated by a conventional active support control algorithm; respectively constructing a steady-state model and a small-signal stable model of the network construction converter according to the acquired parameters and the operation power angle; constructing an additional steady-state control structure according to a mathematical relationship in the steady-state model, and calculating a steady-state decoupling coefficient in the additional steady-state control structure under the condition that an off-diagonal element in steady-state control is zero; constructing an additional dynamic control structure according to a mathematical relationship in the small signal stability model, and calculating a dynamic decoupling coefficient in the additional dynamic control structure under the condition that a non-diagonal element in dynamic control is zero; and based on the steady-state decoupling coefficient and the dynamic decoupling coefficient, carrying out fusion type decoupling control on the network construction converter.

Description

Technical Field

[0001] The present invention belongs to the field of converters, and relates to a control method for a grid-connected converter, and in particular to an active support control method and device for a grid-connected converter based on frequency-voltage coupling. Background Art

[0002] In power systems with high penetration of power electronics, the control functions and processes of power electronic systems such as new energy power generation devices and flexible DC equipment are complex, which profoundly affects the dynamic response characteristics of the power system, making the operation and control of power systems with high penetration of power electronics face huge challenges.

[0003] In order to improve the safety and stability of power systems with high penetration of power electronics, the use of grid-type converters is an effective and economical means. Grid-type converters can actively establish the frequency and voltage of the system without tracking the grid frequency. Therefore, they can not only work in grid-connected mode, but also in active support mode. Generally, the synchronization strategy of grid-type converters is similar to that of traditional synchronous generator control. By simulating the power frequency and voltage characteristics of synchronous generators and designing reasonable frequency and voltage control loops, the port characteristics of the entire converter can be regarded as a synchronous generator, and flexible networking can be performed accordingly.

[0004] However, in related technologies, the coupling characteristics of the frequency and voltage of the grid-connected converter itself under active support control are usually ignored, resulting in coupling between its active and reactive power. Power oscillations will occur when the power changes. In addition, unreasonable system parameters can easily amplify the above oscillations, thereby causing system instability. Summary of the invention

[0005] In view of this, the present invention discloses a method, device, equipment and storage medium for active support control of a grid-connected converter based on frequency-voltage coupling, which can solve the deficiencies existing in the related art.

[0006] To achieve the above purpose, the present invention discloses the following technical solutions: According to a first aspect of the present invention, a method for active support control of a grid-connected converter based on frequency-voltage coupling is proposed, wherein the method comprises: Obtain system parameters and operating parameters of the grid-forming converter for calculating additional control parameters; wherein the system parameters include: equivalent voltage VC on the AC side inside the converter, equivalent inductance LC on the AC side inside the converter, equivalent resistance RC on the AC side inside the converter, active synchronous control loop PI parameters, AC voltage control loop PI parameters, reactive synchronous control loop PI parameters, and the operating parameters include: equivalent voltage V g , the equivalent inductance L of the AC grid to which the converter is connected g, the equivalent resistance Rg of the AC grid connected to the converter, the exchange active power P between the converter and the AC grid, the exchange reactive power Q between the converter and the AC grid, the exchange reactive power wg between the AC grids, and the power angle θ g , the power angle θ generated by the conventional active support control algorithm 旧 * ; According to the power angle θ between AC power grids g and the power angle θ generated by the conventional active support control algorithm 旧 * Calculate the operating power angle θ of the grid-connecting converter, and construct a steady-state model and a small-signal stability model of the grid-connecting converter according to the acquired parameters and the operating power angle θ; Constructing an additional steady-state control structure according to the mathematical relationship in the steady-state model, and calculating a steady-state decoupling coefficient in the additional steady-state control structure on the condition that the non-diagonal elements in the steady-state control are zero; Constructing an additional dynamic control structure according to the mathematical relationship in the small signal stability model, and calculating the dynamic decoupling coefficient in the additional dynamic control structure on the condition that the off-diagonal elements in the dynamic control are zero; Based on the steady-state decoupling coefficient and the dynamic decoupling coefficient, a fusion decoupling control is performed on the grid-connected converter.

[0007] According to a second aspect of the present invention, a frequency-voltage coupling-based active support control device for a grid-connected converter is proposed, wherein the device comprises: Acquisition unit: acquires system parameters and operation parameters of the grid-forming converter for calculating additional control parameters; wherein the system parameters include: equivalent voltage VC on the AC side inside the converter, equivalent inductance LC on the AC side inside the converter, equivalent resistance RC on the AC side inside the converter, active synchronous control loop PI parameters, AC voltage control loop PI parameters, reactive synchronous control loop PI parameters; the operation parameters include: equivalent voltage V g , the equivalent inductance L of the AC grid to which the converter is connected g , the equivalent resistance Rg of the AC grid connected to the converter, the exchange active power P between the converter and the AC grid, the exchange reactive power Q between the converter and the AC grid, the exchange reactive power wg between the AC grids, and the power angle θ g , the power angle θ generated by the conventional active support control algorithm 旧 * ; Calculation unit: According to the power angle θ between AC power grids g and the power angle θ generated by the conventional active support control algorithm 旧 * Calculate the operating power angle θ of the grid-connecting converter, and construct a steady-state model and a small-signal stability model of the grid-connecting converter according to the acquired parameters and the operating power angle θ; A first construction unit: constructing an additional steady-state control structure according to the mathematical relationship in the steady-state model, and calculating a steady-state decoupling coefficient in the additional steady-state control structure on the condition that the non-diagonal elements in the steady-state control are zero; A second construction unit: constructing an additional dynamic control structure according to the mathematical relationship in the small signal stability model, and calculating the dynamic decoupling coefficient in the additional dynamic control structure on the condition that the non-diagonal elements in the dynamic control are zero; Control unit: performs fusion decoupling control on the grid-connected converter based on the steady-state decoupling coefficient and the dynamic decoupling coefficient.

[0008] According to a third aspect of the present invention, an electronic device is provided, comprising: processor; a memory for storing processor-executable instructions; The processor implements the steps of the method described in the first aspect by running the executable instructions.

[0009] According to a fourth aspect of the present invention, a computer-readable storage medium is provided, on which computer instructions are stored, and when the instructions are executed by a processor, the steps of the method described in the first aspect are implemented.

[0010] It can be seen from the above technical scheme that the active support control method of the grid-connected converter based on frequency-voltage coupling disclosed in the present invention takes into account the frequency-voltage coupling characteristics, constructs a steady-state model and a small-signal stability model of the grid-connected converter according to the acquired system parameters and operating parameters of the grid-connected converter, and further constructs an additional steady-state control structure and an additional dynamic control structure, thereby calculating the steady-state decoupling coefficient and the dynamic decoupling coefficient for realizing decoupling control, which can not only effectively solve the active-reactive decoupling of the steady-state operation of the grid-connected converter under the active support control mode, and reduce the difficulty of coordinated control of related systems, but also effectively solve the active-reactive decoupling of the dynamic operation of the grid-connected converter under the active support control mode, ensure the safe and stable operation of multiple operating conditions of the related systems, and reduce the impact voltage and current during operating condition switching. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of the coupling phenomenon of active and reactive regulation under conventional active support control of a grid-connected converter provided by an exemplary embodiment.

[0012] Figure 2 It is a flow chart of an active support control method for a grid-connected converter based on frequency-voltage coupling provided by an exemplary embodiment.

[0013] Figure 3 is a schematic diagram of an additional control structure provided by an exemplary embodiment.

[0014] Figure 4 It is a schematic structural diagram of a device provided by an exemplary embodiment.

[0015] Figure 5 It is a block diagram of an active support control device for a grid-connected converter based on frequency-voltage coupling provided by an exemplary embodiment. DETAILED DESCRIPTION

[0016] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with one or more embodiments of the present invention. Instead, they are merely examples of devices and methods consistent with some aspects of one or more embodiments of the present invention as detailed in the appended claims.

[0017] It should be noted that: in other embodiments, the steps of the corresponding method are not necessarily performed in the order shown and described in the present invention. In some other embodiments, the steps included in the method may be more or less than those described in the present invention. In addition, a single step described in the present invention may be decomposed into multiple steps for description in other embodiments; and multiple steps described in the present invention may be combined into a single step for description in other embodiments.

[0018] To further illustrate the present invention, the following examples are provided: In power systems with high penetration of power electronics, the control functions and processes of power electronic systems such as new energy power generation devices and flexible DC equipment are complex, which profoundly affects the dynamic response characteristics of the power system, making the operation and control of power systems with high penetration of power electronics face huge challenges.

[0019] In order to improve the safety and stability of power systems with high penetration of power electronics, the use of grid-type converters is an effective and economical means. Grid-type converters can actively establish the frequency and voltage of the system without tracking the grid frequency. Therefore, they can not only work in grid-connected mode, but also in active support mode. Generally, the synchronization strategy of grid-type converters is similar to that of traditional synchronous generator control. By simulating the power frequency and voltage characteristics of synchronous generators and designing reasonable frequency and voltage control loops, the port characteristics of the entire converter can be regarded as a synchronous generator, and flexible networking can be performed accordingly.

[0020] However, in related technologies, the coupling characteristics of the frequency and voltage of the grid-connected converter itself under active support control are usually ignored, resulting in coupling between its active and reactive power. Power oscillations will occur when the power changes. In addition, unreasonable system parameters can easily amplify the above oscillations, thereby causing system instability.

[0021] like Figure 1 As shown in the figure, the coupling phenomenon of active and reactive regulation under conventional active support control of the grid-connected converter is given. Obviously, due to the failure to consider the frequency-voltage coupling characteristics, there is a coupling phenomenon in the active and reactive regulation of the grid-connected converter under conventional active support control, which causes large oscillations in reactive power when active power is regulated. In this way, when the grid-connected converter operates under diverse working conditions, the above oscillations may be further coupled due to the interaction with other system parameters, resulting in continuous oscillations that endanger system safety.

[0022] In order to solve the deficiencies existing in the related art, the present invention proposes an active support control method for a grid-connected converter based on frequency-voltage coupling.

[0023] Figure 2 FIG. 1 is a flowchart of an active support control method for a grid-connected converter based on frequency-voltage coupling provided by an exemplary embodiment. Figure 2 As shown, the method may include the following steps: Step 202, obtaining system parameters and operating parameters of the grid-forming converter for calculating additional control parameters; wherein the system parameters include: equivalent voltage VC on the AC side inside the converter, equivalent inductance LC on the AC side inside the converter, equivalent resistance RC on the AC side inside the converter, active synchronous control loop PI parameters, AC voltage control loop PI parameters, reactive synchronous control loop PI parameters, and the operating parameters include: equivalent voltage V g , the equivalent inductance L of the AC grid to which the converter is connected g , the equivalent resistance Rg of the AC grid connected to the converter, the exchange active power P between the converter and the AC grid, the exchange reactive power Q between the converter and the AC grid, the exchange reactive power wg between the AC grids, and the power angle θ g , the power angle θ generated by the conventional active support control algorithm 旧 * .

[0024] Step 204: according to the power angle θ between the AC power grids g and the power angle θ generated by the conventional active support control algorithm 旧 * Calculate the operating power angle θ of the grid-connecting converter, and construct a steady-state model and a small-signal stability model of the grid-connecting converter according to the acquired parameters and the operating power angle θ.

[0025] In one embodiment, the power angle θ between the AC power grids g and the power angle θ generated by the conventional active support control algorithm 旧 * Calculate the operating power angle θ of the grid-connected converter, including: Calculate the power angle θ between AC grids g and the power angle θ generated by the conventional active support control algorithm 旧 *, and the angle of attack difference is used as the operating power angle θ of the grid-forming converter, which is expressed by the formula: .

[0026] In one embodiment, according to the relevant parameters obtained in step 202 and the operating power angle θ of the grid-forming converter, the steady-state model of the grid-forming converter is calculated to obtain the active and reactive coupling coefficients (i.e., mathematical relationships) of the grid-forming converter in the steady state. The specific calculation is as follows: ; The steady-state model takes the operating power angle θ and the grid voltage Vs as input, and takes the active power P and reactive power Q as output. θP (Steady state) is the mathematical relationship between active power P and operating power angle θ, XJ VP (Steady state) is the mathematical relationship between active power P and grid voltage Vs, XJ θQ (Steady state) is the mathematical relationship between reactive power Q and operating power angle θ, XJ VQ (Steady state) is the mathematical relationship between reactive power Q and grid voltage Vs.

[0027] It should be noted that since the lines in the power grid usually contain resistance and inductance, the above XJ θP (steady state), XJ VP (steady state), XJ θQ (steady state), XJ VQ (Steady state) is usually nonlinear and non-independent, so it needs to be obtained through polynomial function fitting based on curve scanning, and there is no unique expression.

[0028] In one embodiment, according to the relevant parameters obtained in step 202 and the operating power angle θ of the grid-forming converter, the small signal stability model of the grid-forming converter is calculated to obtain the active and reactive coupling coefficients (i.e., mathematical relationships) of the grid-forming converter under small signal conditions. The specific calculation is as follows: ; Among them, the small signal increment ∆P of active power P and the small signal increment ∆Q of reactive power Q are taken as output, the small signal increment ∆θ of grid converter operation power angle θ and the small signal increment ∆V of grid voltage Vs are taken as output. s For input, XJ θP (Dynamic) is the mathematical relationship between active power P and operating power angle θ, XJVP (Dynamic) is the mathematical relationship between active power P and grid voltage Vs, XJ θQ (Dynamic) is the mathematical relationship between reactive power Q and operating power angle θ, XJ VQ (Dynamic) is the mathematical relationship between reactive power Q and grid voltage Vs.

[0029] It should be noted that, unlike the above XJ θP (steady state), XJ VP (steady state), XJ θQ (steady state), XJ VQ (steady state) similar, XJ θP (Dynamic), XJ VP (Dynamic), XJ θQ (Dynamic), XJ VQ (Dynamic) is usually nonlinear and non-independent, so it also needs to be obtained through polynomial function fitting based on curve scanning, and there is no unique expression.

[0030] Step 206 , constructing an additional steady-state control structure according to the mathematical relationship in the steady-state model, and calculating the steady-state decoupling coefficient in the additional steady-state control structure on the condition that the non-diagonal elements in the steady-state control are zero.

[0031] Step 208 : constructing an additional dynamic control structure according to the mathematical relationship in the small signal stability model, and calculating the dynamic decoupling coefficient in the additional dynamic control structure on the condition that the non-diagonal elements in the dynamic control are zero.

[0032] like Figure 3 As shown in the figure, the calculation formulas for the steady-state decoupling coefficient and the dynamic decoupling coefficient are: ; Among them, FJ Vθ (Steady state) is the steady-state decoupling coefficient of active power P and operating voltage V, XJ θV (steady state) is the steady-state decoupling coefficient of reactive power Q and operating power angle θ.

[0033] ; Among them, FJ Vθ (Dynamic) is the dynamic decoupling coefficient of active power P and operating voltage V, XJ θV (Dynamic) is the dynamic decoupling coefficient of reactive power Q and operating power angle θ.

[0034] Step 210: Perform fusion decoupling control on the grid-connected converter based on the steady-state decoupling coefficient and the dynamic decoupling coefficient.

[0035] In one embodiment, the performing fusion decoupling control on the grid-connected converter based on the steady-state decoupling coefficient and the dynamic decoupling coefficient includes: A fusion decoupling model is constructed according to the steady-state decoupling coefficient and the dynamic decoupling coefficient, and fusion decoupling control is performed based on the fusion decoupling model. The fusion decoupling model is: ; Among them, FJ Vθ (Steady state) is the steady-state decoupling coefficient of active power P and operating voltage V, XJ θV (Steady state) is the steady-state decoupling coefficient of reactive power Q and operating power angle θ, FJ Vθ (Dynamic) is the dynamic decoupling coefficient of active power P and operating voltage V, XJ θV (Dynamic) is the dynamic decoupling coefficient of reactive power Q and operating power angle θ.

[0036] In this embodiment, the frequency-voltage coupling characteristics are taken into consideration, and a steady-state model and a small-signal stability model of the grid-forming converter are constructed according to the acquired system parameters and operating parameters of the grid-forming converter, and an additional steady-state control structure and an additional dynamic control structure are further constructed to calculate the steady-state decoupling coefficient and the dynamic decoupling coefficient for realizing decoupling control. This can not only effectively solve the active-reactive decoupling of the steady-state operation of the grid-forming converter under the active support control mode, and reduce the difficulty of coordinated control of related systems, but also effectively solve the active-reactive decoupling of the dynamic operation of the grid-forming converter under the active support control mode, ensure the safe and stable operation of related systems under multiple operating conditions, and reduce the impact voltage and current during operating condition switching.

[0037] Figure 4 is a schematic structural diagram of a device provided by an exemplary embodiment. Figure 4 At the hardware level, the device includes a processor 402, an internal bus 404, a network interface 406, a memory 408, and a non-volatile memory 410, and may also include hardware required for other functions. One or more embodiments of the present invention may be implemented based on software, such as the processor 402 reading the corresponding computer program from the non-volatile memory 410 into the memory 408 and then running it. Of course, in addition to the software implementation, one or more embodiments of the present invention do not exclude other implementations, such as logic devices or a combination of software and hardware, etc., that is, the execution subject of the following processing flow is not limited to each logic unit, but may also be hardware or logic devices.

[0038] Please refer to Figure 5 , an active support control device for grid-connected converters based on frequency-voltage coupling can be applied to Figure 5 In the device shown, to implement the technical solution of the present invention, the device may include: The acquisition unit 502 is used to acquire the system parameters and operating parameters of the grid-forming converter for calculating the additional control parameters; wherein the system parameters include: the equivalent voltage VC on the AC side inside the converter, the equivalent inductance LC on the AC side inside the converter, the equivalent resistance RC on the AC side inside the converter, the active synchronous control loop PI parameters, the AC voltage control loop PI parameters, and the reactive synchronous control loop PI parameters; the operating parameters include: the equivalent voltage V g , the equivalent inductance L of the AC grid to which the converter is connected g , the equivalent resistance Rg of the AC grid connected to the converter, the exchange active power P between the converter and the AC grid, the exchange reactive power Q between the converter and the AC grid, the exchange reactive power wg between the AC grids, and the power angle θ g , the power angle θ generated by the conventional active support control algorithm 旧 * ; The calculation unit 504 is used to calculate the power angle θ between the AC power grids. g and the power angle θ generated by the conventional active support control algorithm 旧 * Calculate the operating power angle θ of the grid-connecting converter, and construct a steady-state model and a small-signal stability model of the grid-connecting converter according to the acquired parameters and the operating power angle θ; A first construction unit 506 is used to construct an additional steady-state control structure according to the mathematical relationship in the steady-state model, and calculate the steady-state decoupling coefficient in the additional steady-state control structure on the condition that the non-diagonal elements in the steady-state control are zero; A second construction unit 508 is used to construct an additional dynamic control structure according to the mathematical relationship in the small signal stability model, and calculate the dynamic decoupling coefficient in the additional dynamic control structure on the condition that the non-diagonal elements in the dynamic control are zero; The control unit 510 is used to perform fusion decoupling control on the grid-connected converter based on the steady-state decoupling coefficient and the dynamic decoupling coefficient.

[0039] Optionally, the calculation unit 504 is specifically used for: Calculate the power angle θ between AC power grids g and the power angle θ generated by the conventional active support control algorithm 旧 *, and use the angle of attack difference as the operating power angle θ of the grid converter.

[0040] Optionally, the steady-state model is as follows: ; The steady-state model takes the operating power angle θ and the grid voltage Vs as input, and takes the active power P and reactive power Q as output. θP(Steady state) is the mathematical relationship between active power P and operating power angle θ, XJ VP (Steady state) is the mathematical relationship between active power P and grid voltage Vs, XJ θQ (Steady state) is the mathematical relationship between reactive power Q and operating power angle θ, XJ VQ (Steady state) is the mathematical relationship between reactive power Q and grid voltage Vs.

[0041] Optionally, the calculation formula for calculating the steady-state decoupling coefficient is as follows: ; Among them, FJ Vθ (Steady state) is the steady-state decoupling coefficient of active power P and operating voltage V, XJ θV (steady state) is the steady-state decoupling coefficient of reactive power Q and operating power angle θ.

[0042] Optionally, the small signal stability model is as follows: ; Among them, the small signal increment ∆P of active power P and the small signal increment ∆Q of reactive power Q are taken as output, the small signal increment ∆θ of grid converter operation power angle θ and the small signal increment ∆V of grid voltage Vs are taken as output. s For input, XJ θP (Dynamic) is the mathematical relationship between active power P and operating power angle θ, XJ VP (Dynamic) is the mathematical relationship between active power P and grid voltage Vs, XJ θQ (Dynamic) is the mathematical relationship between reactive power Q and operating power angle θ, XJ VQ (Dynamic) is the mathematical relationship between reactive power Q and grid voltage Vs.

[0043] Optionally, the calculation formula for calculating the dynamic decoupling coefficient is as follows: ; Among them, FJ Vθ (Dynamic) is the dynamic decoupling coefficient of active power P and operating voltage V, XJ θV (Dynamic) is the dynamic decoupling coefficient of reactive power Q and operating power angle θ.

[0044] Optionally, the control unit 510 is specifically configured to: A fusion decoupling model is constructed according to the steady-state decoupling coefficient and the dynamic decoupling coefficient, and fusion decoupling control is performed based on the fusion decoupling model. The fusion decoupling model is: ; Among them, FJ Vθ (Steady state) is the steady-state decoupling coefficient of active power P and operating voltage V, XJ θV(Steady state) is the steady-state decoupling coefficient of reactive power Q and operating power angle θ, FJ Vθ (Dynamic) is the dynamic decoupling coefficient of active power P and operating voltage V, XJ θV (Dynamic) is the dynamic decoupling coefficient of reactive power Q and operating power angle θ.

[0045] The systems, devices, modules or units described in the above embodiments may be implemented by computer chips or entities, or by products with certain functions. A typical implementation device is a computer, which may be in the form of a personal computer, a laptop computer, a cellular phone, a camera phone, a smart phone, a personal digital assistant, a media player, a navigation device, an email transceiver, a game console, a tablet computer, a wearable device or a combination of any of these devices.

[0046] In a typical configuration, a computer includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0047] Memory may include non-permanent storage in a computer-readable medium, in the form of random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of a computer-readable medium.

[0048] Computer-readable media include permanent and non-permanent, removable and non-removable media that can be used to store information by any method or technology. Information can be computer-readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassettes, disk storage, quantum memory, graphene-based storage media or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer-readable media does not include temporary computer-readable media (transitory media), such as modulated data signals and carrier waves.

[0049] With respect to the computer-readable medium (or computer-readable storage medium) as described above or in any other form, computer instructions may be stored thereon, and when the instructions are executed by a processor, one or more of the above-mentioned embodiments are implemented, thereby realizing the technical solution of the present invention.

[0050] The present invention also proposes a computer program, which, when executed by a processor, implements one or more of the above embodiments, thereby realizing the technical solution of the present invention. The computer program may be specifically recorded in the above or any other form of computer-readable medium, and the present invention is not limited thereto.

[0051] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0052] The above describes specific embodiments of the present invention. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the embodiments and still achieve the desired results. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0053] The terms used in one or more embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit one or more embodiments of the present invention. The singular forms of "a", "said" and "the" used in one or more embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0054] It should be understood that although the terms first, second, third, etc. may be used to describe various information in one or more embodiments of the present invention, these information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of one or more embodiments of the present invention, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining".

[0055] The above description is merely a preferred embodiment of one or more embodiments of the present invention and is not intended to limit one or more embodiments of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of one or more embodiments of the present invention shall be included in the scope of protection of one or more embodiments of the present invention.

Claims

1. A method for active support control of a grid-connected converter based on frequency-voltage coupling, characterized in that: The method comprises: Obtain system parameters and operating parameters of the grid-forming converter for calculating additional control parameters; wherein the system parameters include: equivalent voltage VC on the AC side inside the converter, equivalent inductance LC on the AC side inside the converter, equivalent resistance RC on the AC side inside the converter, active synchronous control loop PI parameters, AC voltage control loop PI parameters, reactive synchronous control loop PI parameters, and the operating parameters include: equivalent voltage V g , the equivalent inductance L of the AC grid to which the converter is connected g , the equivalent resistance Rg of the AC grid connected to the converter, the exchange active power P between the converter and the AC grid, the exchange reactive power Q between the converter and the AC grid, the exchange reactive power wg between the AC grids, and the power angle θ g , the power angle θ generated by the conventional active support control algorithm 旧 * ; According to the power angle θ between AC power grids g and the power angle θ generated by the conventional active support control algorithm 旧 * Calculate the operating power angle θ of the grid-connecting converter, and construct a steady-state model and a small-signal stability model of the grid-connecting converter according to the acquired parameters and the operating power angle θ; Constructing an additional steady-state control structure according to the mathematical relationship in the steady-state model, and calculating a steady-state decoupling coefficient in the additional steady-state control structure on the condition that the non-diagonal elements in the steady-state control are zero; Constructing an additional dynamic control structure according to the mathematical relationship in the small signal stability model, and calculating the dynamic decoupling coefficient in the additional dynamic control structure on the condition that the off-diagonal elements in the dynamic control are zero; Based on the steady-state decoupling coefficient and the dynamic decoupling coefficient, a fusion decoupling control is performed on the grid-connected converter.

2. The method according to claim 1, characterized in that According to the power angle θ between the AC power grids g and the power angle θ generated by the conventional active support control algorithm 旧 * Calculate the operating power angle θ of the grid-connected converter, including: Calculate the power angle θ between AC power grids g and the power angle θ generated by the conventional active support control algorithm 旧 *, and use the angle of attack difference as the operating power angle θ of the grid converter.

3. The method according to claim 1, characterized in that The steady-state model is as follows: ； The steady-state model takes the operating power angle θ and the grid voltage Vs as input, and takes the active power P and reactive power Q as output. θP (Steady state) is the mathematical relationship between active power P and operating power angle θ, XJ VP (Steady state) is the mathematical relationship between active power P and grid voltage Vs, XJ θQ (Steady state) is the mathematical relationship between reactive power Q and operating power angle θ, XJ VQ (Steady state) is the mathematical relationship between reactive power Q and grid voltage Vs.

4. The method according to claim 3, characterized in that The calculation formula for calculating the steady-state decoupling coefficient is as follows: ； Among them, FJ Vθ (Steady state) is the steady-state decoupling coefficient of active power P and operating voltage V, XJ θV (steady state) is the steady-state decoupling coefficient of reactive power Q and operating power angle θ.

5. The method according to claim 1, characterized in that The small signal stability model is as follows: ； Among them, the small signal increment ∆P of active power P and the small signal increment ∆Q of reactive power Q are taken as output, the small signal increment ∆θ of grid converter operation power angle θ and the small signal increment ∆V of grid voltage Vs are taken as output. s For input, XJ θP (Dynamic) is the mathematical relationship between active power P and operating power angle θ, XJ VP (Dynamic) is the mathematical relationship between active power P and grid voltage Vs, XJ θQ (Dynamic) is the mathematical relationship between reactive power Q and operating power angle θ, XJ VQ (Dynamic) is the mathematical relationship between reactive power Q and grid voltage Vs.

6. The method according to claim 5, characterized in that The calculation formula for calculating the dynamic decoupling coefficient is as follows: ； Among them, FJ Vθ (Dynamic) is the dynamic decoupling coefficient of active power P and operating voltage V, XJ θV (Dynamic) is the dynamic decoupling coefficient of reactive power Q and operating power angle θ.

7. The method according to claim 1, characterized in that The performing fusion decoupling control on the grid-connected converter based on the steady-state decoupling coefficient and the dynamic decoupling coefficient includes: A fusion decoupling model is constructed according to the steady-state decoupling coefficient and the dynamic decoupling coefficient, and fusion decoupling control is performed based on the fusion decoupling model. The fusion decoupling model is: ； Among them, FJ Vθ (Steady state) is the steady-state decoupling coefficient of active power P and operating voltage V, XJ θV (Steady state) is the steady-state decoupling coefficient of reactive power Q and operating power angle θ, FJ Vθ (Dynamic) is the dynamic decoupling coefficient of active power P and operating voltage V, XJ θV (Dynamic) is the dynamic decoupling coefficient of reactive power Q and operating power angle θ.

8. An active support control device for a grid-connected converter based on frequency-voltage coupling, characterized in that: The device comprises: Acquisition unit: acquires system parameters and operation parameters of the grid-forming converter for calculating additional control parameters; wherein the system parameters include: equivalent voltage VC on the AC side inside the converter, equivalent inductance LC on the AC side inside the converter, equivalent resistance RC on the AC side inside the converter, active synchronous control loop PI parameters, AC voltage control loop PI parameters, reactive synchronous control loop PI parameters; the operation parameters include: equivalent voltage V g , the equivalent inductance L of the AC grid to which the converter is connected g , the equivalent resistance Rg of the AC grid connected to the converter, the exchange active power P between the converter and the AC grid, the exchange reactive power Q between the converter and the AC grid, the exchange reactive power wg between the AC grids, and the power angle θ g , the power angle θ generated by the conventional active support control algorithm 旧 * ; Calculation unit: According to the power angle θ between AC power grids g and the power angle θ generated by the conventional active support control algorithm 旧 * Calculate the operating power angle θ of the grid-connecting converter, and construct a steady-state model and a small-signal stability model of the grid-connecting converter according to the acquired parameters and the operating power angle θ; A first construction unit: constructing an additional steady-state control structure according to the mathematical relationship in the steady-state model, and calculating a steady-state decoupling coefficient in the additional steady-state control structure on the condition that the non-diagonal elements in the steady-state control are zero; A second construction unit: constructing an additional dynamic control structure according to the mathematical relationship in the small signal stability model, and calculating the dynamic decoupling coefficient in the additional dynamic control structure on the condition that the non-diagonal elements in the dynamic control are zero; Control unit: performs fusion decoupling control on the grid-connected converter based on the steady-state decoupling coefficient and the dynamic decoupling coefficient.

9. An electronic device, characterized in that: include: processor; a memory for storing processor-executable instructions; The processor implements the steps of the method according to any one of claims 1 to 7 by running the executable instructions.

10. A computer-readable storage medium having computer instructions stored thereon, characterized in that: When the instruction is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

Images