Operation control method and apparatus for converter in grid-connected system, and converter

Abstract

The present application is applicable to the technical field of power systems. Provided are an operation control method and apparatus for a converter in a grid-connected system, and a converter. The method comprises: during the process of running a first control algorithm, if a first operation mode switching instruction is received, acquiring an actual value of a target electrical parameter of a power system, wherein the target electrical parameter corresponds to a target state variable in a second control algorithm; stopping running the first control algorithm, setting an initial value of the target state variable to be the actual value of the corresponding target electrical parameter, and starting to run the second control algorithm. In this way, smooth switching of a control algorithm can be realized, a transient impact on a power grid when a converter is switched between different control algorithms is reduced, and the stability of a power system is improved.

Description

Operation control method and device of converter in grid-connected system and converter

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on June 28, 2023, with application number 202310781214.6 and invention name “Operation control method, device and converter for converter in grid-connected system”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application belongs to the technical field of power systems, and in particular relates to an operation control method and device for a converter in a grid-connected system, and a converter. Background Art

[0003] Virtual synchronous generator (VSG) technology is used to address the low inertia level issue caused when renewable energy generation systems are connected to the AC grid. It embeds the mathematical model of a traditional synchronous generator into the converter's control algorithm and connects an energy storage system to the DC transmission system for VSG control. This allows the grid-connected system, consisting of the converter and energy storage system, to simulate the rotational inertia and damping characteristics of a traditional synchronous generator, allowing renewable energy generation systems to connect to the grid in the same way as traditional synchronous generators, thereby improving the stability of the power system.

[0004] Grid-connected systems, comprised of converters and energy storage systems, can provide inertia support, primary frequency regulation, and static synchronous compensator (STATCOM) functions for the power system. To provide these different functions, the converters within the grid-connected system must switch between different control algorithms. Switching between these control algorithms can cause transient shocks, such as overcurrent or overvoltage, to the power grid, leading to oscillations and instability in the power system. Technical issues

[0005] In view of this, the embodiments of the present application provide an operation control method, device and converter for a converter in a grid-connected system to solve the technical problem that when the converter in the grid-connected system switches between different control algorithms, it will cause transient impacts to the power grid, thereby reducing the stability of the power system. Technical Solutions

[0006] To achieve the above objectives, this application adopts the following technical solutions:

[0007] In a first aspect, an embodiment of the present application provides an operation control method for a converter in a grid-connected system, comprising:

[0008] During the execution of the first control algorithm, if a first operating mode switching instruction is received, an actual value of a target electrical parameter of the power system is obtained; the target electrical parameter corresponds to a target state variable in the second control algorithm;

[0009] Stop running the first control algorithm, set the initial value of the target state variable to the actual value of the corresponding target electrical parameter, and start running the second control algorithm.

[0010] In an embodiment of the present application, by setting the initial value of the target state variable in the second control algorithm to the actual value of the corresponding target electrical parameter before switching the control algorithm from the first control algorithm to the second control algorithm, the initial value of the target state variable in the second control algorithm can be kept consistent with the actual value of the corresponding target electrical parameter in the power system after switching to the second control algorithm. In this way, smooth switching of the control algorithm can be achieved, the transient impact on the power grid caused by the converter when switching between different control algorithms can be reduced, and the stability of the power system can be improved.

[0011] In an optional implementation of the first aspect, the first control algorithm is a virtual synchronous generator control algorithm, the second control algorithm includes a constant DC voltage control algorithm and a constant reactive power control algorithm; and obtaining the actual value of the target electrical parameter of the power system includes:

[0012] Acquiring an actual value of an active component and an actual value of a reactive component of a grid current of the power system at a first moment, wherein the first moment is a moment when the first working mode switching instruction is received;

[0013] The step of setting the initial value of the target state variable to the actual value of the corresponding target electrical parameter includes:

[0014] Setting the initial value of the first active current state quantity in the second control algorithm to the actual value of the active component of the grid current at the first moment;

[0015] An initial value of the first reactive current state variable in the second control algorithm is set to the actual value of the reactive component of the grid current at the first moment.

[0016] In an embodiment of the present application, when the second control algorithm includes a constant DC voltage control algorithm and a constant reactive power control algorithm, since the target state variables in the second control algorithm include a first active current state quantity and a first reactive current state quantity, when switching from the first control algorithm to the second control algorithm, the initial value of the first active current state quantity and the initial value of the first reactive current state quantity are respectively set to the actual value of the active component and the actual value of the reactive component of the grid current before switching the algorithm, so that the DC bus voltage and DC bus current of the power system can be kept continuous before and after the control algorithm is switched, thereby reducing the transient impact on the AC power grid.

[0017] In an optional implementation of the first aspect, after starting to run the second control algorithm, the method further includes:

[0018] Determining a reference value of the first active current state quantity and a reference value of the first reactive current state quantity at a second moment; the second moment being any moment after the second control algorithm is executed;

[0019] Obtaining an actual value of an active component and an actual value of a reactive component of the grid current at the second moment;

[0020] Based on the reference value of the first active current state quantity, the reference value of the first reactive current state quantity, the actual value of the active component of the grid current and the actual value of the reactive component of the grid current at the second moment, the value of the active component and the value of the reactive component of the output potential of the converter at the second moment are determined; the value of the active component and the value of the reactive component of the output potential are used to control the grid voltage of the power system.

[0021] In an embodiment of the present application, the value of the active component and the value of the reactive component of the output potential of the converter at the second moment are determined during the operation of the second control algorithm. Since the value of the active component and the value of the reactive component of the output potential of the first converter at the second moment are used to control the grid voltage of the power system, the value of the active component and the value of the reactive component of the output potential of the converter can be modulated to obtain a switch modulation signal for controlling the switch module in the converter. The switch modulation signal can be used to realize the switching control of the power module in the converter, thereby realizing the control of the grid voltage, and then realizing the regulation of the reactive power of the AC power grid.

[0022] In an optional implementation of the first aspect, after starting to run the second control algorithm, the method further includes:

[0023] Determining a reference value of the active power state quantity and a reference value of the reactive power state quantity at the second moment;

[0024] Determining a feedback value of the active power state quantity and a feedback value of the reactive power state quantity at the second moment; the feedback value of the active power state quantity and the feedback value of the reactive power state quantity are related to a reference value of a second active current state quantity and a reference value of a second reactive current state quantity in the first control algorithm at the second moment;

[0025] Acquire an actual value of the grid voltage, an actual value of the active component of the grid voltage, an actual value of the reactive component of the grid voltage, and an actual value of the grid frequency at the second moment;

[0026] Obtaining a setting value of the grid frequency and a setting value of the grid voltage;

[0027] Based on the reference value of the active power state quantity at the second moment, the reference value of the reactive power state quantity, the feedback value of the active power state quantity, the feedback value of the reactive power state quantity, the actual value of the grid voltage, the actual value of the active component of the grid voltage, the actual value of the reactive component of the grid voltage, the actual value of the grid frequency, the set value of the grid frequency, the set value of the grid voltage and the rated value of the grid frequency, the reference value of the second active current state quantity and the reference value of the second reactive current state quantity are adjusted.

[0028] In an embodiment of the present application, after the second control algorithm starts to run, the feedback value of the active power state quantity and the feedback value of the reactive power state quantity are determined based on the actual value of the active component and the actual value of the reactive component of the grid voltage, and based on the feedback value of the active power state quantity, the feedback value of the reactive power state quantity and the actual values ​​of each power parameter in the power system, the reference value of the second active current state quantity and the reference value of the second reactive current state quantity in the first control algorithm are adjusted, so that the reference value of the second active current state quantity and the reference value of the second reactive current state quantity in the first control algorithm can always be consistent with the actual values ​​of the corresponding power parameters in the actual power system. In this way, the converter can also achieve smooth switching when switching from the second control algorithm to the first control algorithm, further reducing the transient impact of the algorithm switching on the power grid and improving the stability of the power system.

[0029] In an optional implementation of the first aspect, determining a reference value of the first active current state quantity and a reference value of the first reactive current state quantity at the second moment includes:

[0030] Obtaining a set value of the DC bus voltage of the power system and a set value of the reactive power of the AC power grid;

[0031] Acquire an actual value of the DC bus voltage and an actual value of the reactive power of the AC power grid at a second moment;

[0032] Calculating a reference value of the first active current state quantity at the second moment based on the set value of the DC bus voltage and the actual value of the DC bus voltage at the second moment;

[0033] A reference value of the first reactive current state quantity at the second moment is calculated based on a set value of reactive power of the AC power grid and an actual value of reactive power of the AC power grid at the second moment.

[0034] In an optional implementation of the first aspect, determining a reference value of the active power state quantity and a reference value of the reactive power state quantity at the second moment includes:

[0035] Obtaining an actual value of an active component and an actual value of a reactive component of the grid voltage at the second moment;

[0036] Based on the reference value of the first active current state quantity at the second moment, the reference value of the first reactive current state quantity, the actual value of the active component of the grid voltage, and the actual value of the reactive component of the grid voltage, the reference value of the active power state quantity and the reference value of the reactive power state quantity at the second moment are determined.

[0037] In an optional implementation of the first aspect, determining a reference value of the active power state quantity and a reference value of the reactive power state quantity at the second moment includes:

[0038] Acquire an actual value of the active component of the grid voltage, an actual value of the reactive component of the grid voltage, an actual value of the active component of the grid current, and an actual value of the reactive component of the grid current at the second moment;

[0039] Based on the actual value of the active component of the grid voltage at the second moment, the actual value of the reactive component of the grid voltage, the actual value of the active component of the grid current, and the actual value of the reactive component of the grid current, the reference value of the active power state quantity and the reference value of the reactive power state quantity at the second moment are determined.

[0040] In an optional implementation of the first aspect, determining the feedback value of the active power state quantity and the feedback value of the reactive power state quantity at the second moment includes:

[0041] Obtaining an actual value of an active component and an actual value of a reactive component of the grid voltage at the second moment;

[0042] Based on the reference value of the second active current state quantity at the second moment, the reference value of the second reactive current state quantity, the actual value of the active component of the grid voltage, and the actual value of the reactive component of the grid voltage, the feedback value of the active power state quantity and the feedback value of the reactive power state quantity at the second moment are calculated.

[0043] In an optional implementation of the first aspect, the method further includes:

[0044] During the execution of the first control algorithm, obtaining, at a third moment, an actual value of the active power of the power system, an actual value of the reactive power, an actual value of the grid frequency, an actual value of the grid voltage, an actual value of the active component of the grid voltage, an actual value of the reactive component of the grid voltage, an actual value of the active component of the grid current, and an actual value of the reactive component of the grid current;

[0045] Acquiring the set value of the active power, the set value of the reactive power, the set value of the grid frequency, and the set value of the grid voltage;

[0046] Determining a reference value of a second active current state quantity and a reference value of a second reactive current state quantity at the third moment based on the actual value of the active power, the actual value of the reactive power, the actual value of the grid frequency, the actual value of the grid voltage, the actual value of the active component of the grid voltage, the actual value of the reactive component of the grid voltage, the set value of the active power, the set value of the reactive power, the set value of the grid frequency, and the set value of the grid voltage at the third moment;

[0047] Based on the reference value of the active current state quantity at the third moment, the reference value of the second reactive current state quantity, the actual value of the active component of the grid current and the actual value of the reactive component of the grid current, the value of the active component and the value of the reactive component of the output potential of the converter at the third moment are determined; the value of the active component and the value of the reactive component of the output potential of the converter at the third moment are used to adjust the grid frequency of the power system.

[0048] In an embodiment of the present application, the value of the active component and the value of the reactive component of the output potential of the converter at the third moment are determined during the operation of the first control algorithm. Since the value of the active component and the value of the reactive component of the output potential of the first converter at the third moment are used to control the grid frequency of the power system, the value of the active component and the value of the reactive component of the output potential of the converter can be modulated to obtain a switching modulation signal for controlling the switching module in the converter, and the switching control of the power module in the converter is realized by the switching modulation signal, thereby realizing the regulation of the grid frequency.

[0049] In an optional implementation of the first aspect, the first control algorithm is a virtual synchronous generator control algorithm, the second control algorithm includes a constant DC voltage control algorithm and the virtual synchronous generator control algorithm; and obtaining the actual value of the target electrical parameter of the power system includes:

[0050] Acquiring an actual value of an active component of a grid current of the power system at a first moment; the first moment being a moment when the first working mode switching instruction is received;

[0051] The step of setting the initial value of the target state variable to the actual value of the corresponding target electrical parameter includes:

[0052] An initial value of the first active current state variable in the second control algorithm is set to the actual value of the active component of the grid current at the first moment.

[0053] In an embodiment of the present application, when the second control algorithm is a constant DC voltage and VSG control algorithm, since the target state variable in the second control algorithm only includes the active current state quantity, when switching from the first control algorithm to the second control algorithm, the initial value of the active current state quantity in the second control algorithm is set to the actual value of the active component of the grid current before switching the algorithm, so that the DC bus voltage and DC bus current of the power system can maintain continuity before and after the control algorithm is switched, thereby avoiding transient shocks to the AC power grid.

[0054] In an optional implementation of the first aspect, after starting to run the second control algorithm, the method further includes:

[0055] determining a reference value of the first active current state quantity at a second moment;

[0056] determining a reference value of a second reactive current state at the second moment;

[0057] Obtaining an actual value of an active component and an actual value of a reactive component of the grid current at the second moment;

[0058] Based on the reference value of the first active current state quantity at the second moment, the reference value of the second reactive current state quantity, the actual value of the active component of the grid current and the actual value of the reactive component of the grid current, the value of the active component and the value of the reactive component of the output potential of the converter at the second moment are determined; the value of the active component and the value of the reactive component of the output potential of the converter at the second moment are used to control the grid voltage of the power system.

[0059] In an embodiment of the present application, the value of the active component and the value of the reactive component of the output potential of the converter at the second moment are determined during the operation of the second control algorithm. Since the value of the active component and the value of the reactive component of the output potential of the first converter at the second moment are used to control the grid voltage of the power system, the value of the active component and the value of the reactive component of the output potential of the converter can be modulated to obtain a switching modulation signal for controlling the switching module in the converter, and the switching control of the power module in the converter is realized by the switching modulation signal, thereby realizing control of the grid voltage.

[0060] In an optional implementation of the first aspect, determining a reference value of the first active current state quantity at the second moment includes:

[0061] Obtaining a set value of a DC bus voltage of the power system;

[0062] Obtaining an actual value of the DC bus voltage at the second moment;

[0063] Based on the set value of the DC bus voltage and the actual value of the DC bus voltage at the second moment, a reference value of the first active current state quantity at the second moment is calculated.

[0064] In an optional implementation of the first aspect, determining a reference value of the second reactive current state at the second moment includes:

[0065] determining a reference value of the active power state quantity at the second moment;

[0066] determining a feedback value of the active power state quantity at the second moment;

[0067] Acquire an actual value of reactive power of the power system, an actual value of an active component of the grid voltage, and an actual value of a reactive component of the grid voltage at the second moment;

[0068] Obtaining a setting value of the reactive power, a setting value of the grid voltage, and a setting value of the grid frequency;

[0069] Based on the reference value of the active power state quantity at the second moment, the feedback value of the active power state quantity, the actual value of the reactive power, the actual value of the active component of the grid voltage, the actual value of the reactive component of the grid voltage, the set value of the reactive power, the set value of the grid voltage, the set value of the grid frequency and the rated value of the grid frequency, determine the reference value of the second active current state quantity and the reference value of the second reactive current state quantity at the second moment.

[0070] In an optional implementation of the first aspect, determining the reference value of the active power state quantity at the second moment includes:

[0071] Based on the reference value of the first active current state quantity at the second moment, the reference value of the second reactive current state quantity, the actual value of the active component of the grid voltage and the actual value of the reactive component of the grid voltage, the reference value of the active power state quantity at the second moment is determined.

[0072] In an optional implementation of the first aspect, determining the reference value of the active power state quantity at the second moment includes:

[0073] Obtaining an actual value of an active component and an actual value of a reactive component of the grid current at the second moment;

[0074] Based on the actual value of the active component of the grid voltage at the second moment, the actual value of the reactive component of the grid voltage, the actual value of the active component of the grid current, and the actual value of the reactive component of the grid current, the reference value of the active power state quantity at the second moment is determined.

[0075] In an optional implementation of the first aspect, determining the feedback value of the active power state quantity at the second moment includes:

[0076] Based on the reference value of the second active current state quantity at the second moment, the reference value of the second reactive current state quantity, the actual value of the active component of the grid voltage and the actual value of the reactive component of the grid voltage, the feedback value of the active power state quantity at the second moment is determined.

[0077] In an optional implementation of the first aspect, the method further includes:

[0078] During the execution of the first control algorithm, obtaining, at a third moment, an actual value of the active power of the power system, an actual value of the reactive power, an actual value of the grid frequency, an actual value of the grid voltage, an actual value of the active component of the grid voltage, an actual value of the reactive component of the grid voltage, an actual value of the active component of the grid current, and an actual value of the reactive component of the grid current;

[0079] Acquiring the set value of the active power, the set value of the reactive power, the set value of the grid frequency, and the set value of the grid voltage;

[0080] Determining a reference value of a second active current state quantity and a reference value of a second reactive current state quantity at the third moment based on the actual value of the active power, the actual value of the reactive power, the actual value of the grid frequency, the actual value of the grid voltage, the actual value of the active component of the grid voltage, the actual value of the reactive component of the grid voltage, the set value of the active power, the set value of the reactive power, the set value of the grid frequency, and the set value of the grid voltage at the third moment;

[0081] Based on the reference value of the active current state quantity at the third moment, the reference value of the second reactive current state quantity, the actual value of the active component of the grid current, and the actual value of the reactive component of the grid current, the value of the active component and the value of the reactive component of the output potential of the converter at the third moment are determined; the value of the active component and the value of the reactive component of the output potential of the converter at the third moment are used to regulate the grid voltage of the power system.

[0082] In an embodiment of the present application, the value of the active component and the value of the reactive component of the output potential of the converter at the third moment are determined during the operation of the first control algorithm. Since the value of the active component and the value of the reactive component of the output potential of the first converter at the third moment are used to control the grid frequency of the power system, the value of the active component and the value of the reactive component of the output potential of the converter can be modulated to obtain a switching modulation signal for controlling the switching module in the converter, and the switching control of the power module in the converter is realized by the switching modulation signal, thereby realizing the regulation of the grid frequency.

[0083] In a second aspect, an embodiment of the present application provides an operation control device for a converter in a grid-connected system, comprising:

[0084] an acquisition module, configured to acquire an actual value of a target electrical parameter of the power system if a first operating mode switching instruction is received during the execution of the first control algorithm; the target electrical parameter corresponds to a target state variable in the second control algorithm;

[0085] The setting module is used to stop running the first control algorithm, set the initial value of the target state variable to the actual value of the corresponding target electrical parameter, and start running the second control algorithm.

[0086] In a third aspect, an embodiment of the present application provides another operation control device for a converter in a grid-connected system, comprising a memory and a computer program stored in the memory and executable on a processor, wherein when the processor executes the computer program, the operation control method as described in any optional implementation of the first aspect above is implemented.

[0087] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, it implements the operation control method as described in any optional implementation of the first aspect above.

[0088] In a fifth aspect, an embodiment of the present application provides a converter, comprising a converter module and an operation control device for the converter in the grid-connected system as described in the second aspect above.

[0089] It can be understood that the beneficial effects of the second to fifth aspects mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0090] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0091] FIG1 is a schematic structural diagram of a power system provided in an embodiment of the present application;

[0092] FIG2 is a schematic architecture diagram of a grid-connected system to which an operation control method for a converter in a grid-connected system provided by an embodiment of the present application is applicable;

[0093] FIG3 is a schematic flow chart of a method for controlling the operation of a converter in a grid-connected system provided by an embodiment of the present application;

[0094] FIG4 is a schematic flow chart of an operation control method of a converter in a grid-connected system provided by another embodiment of the present application;

[0095] FIG5 is a schematic flow chart of an operation control method of a converter in a grid-connected system provided by another embodiment of the present application;

[0096] FIG6 is a schematic flow chart of a method for controlling the operation of a converter in a grid-connected system provided by another embodiment of the present application;

[0097] FIG7 is a schematic flow chart of a method for controlling the operation of a converter in a grid-connected system provided by another embodiment of the present application;

[0098] FIG8 is a schematic structural diagram of an operation control device for a converter provided in an embodiment of the present application;

[0099] FIG9 is a schematic structural diagram of an operation control device for a converter provided in another embodiment of the present application;

[0100] FIG10 is a schematic structural diagram of an operation control device for a converter provided in another embodiment of the present application;

[0101] FIG11 is a schematic structural diagram of an operation control device for a converter provided in another embodiment of the present application;

[0102] FIG12 is a schematic structural diagram of an operation control device for a converter provided in another embodiment of the present application;

[0103] FIG13 is a schematic structural diagram of an operation control device for a converter provided in another embodiment of the present application;

[0104] FIG14 is a schematic structural diagram of an operation control device for a converter provided in another embodiment of the present application;

[0105] FIG15 is a schematic structural diagram of an operation control device for a converter provided in another embodiment of the present application;

[0106] FIG16 is a schematic structural diagram of an operation control device for a converter provided in another embodiment of the present application;

[0107] FIG17 is a schematic structural diagram of an operation control device for a converter provided in yet another embodiment of the present application. Modes for Carrying Out the Invention

[0108] The following embodiments of the technical solution of the present application are described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0109] It should be noted that, unless otherwise specified, all technical terms used in the embodiments of this application have the same meanings as those commonly understood by those skilled in the art in the technical field of this application. The technical terms used in the embodiments of this application are only used to explain the specific embodiments of this application and are not intended to limit this application.

[0110] In the description of the embodiments of the present application, the technical terms "include", "comprise", "have" and any variations thereof all mean "include but not limited to", unless otherwise specifically emphasized.

[0111] In the description of the embodiments of the present application, unless otherwise specified, the technical term "plurality" refers to two or more than two, and the technical terms "at least one" and "one or more" refer to one, two or more.

[0112] The technical terms "first" and "second" are only used to distinguish different objects and should not be understood as indicating or implying relative importance or implicitly indicating the quantity, specific order or primary and secondary relationship of the indicated technical features.

[0113] The technical term "and / or" simply describes a relationship between related objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. Furthermore, the character " / " in this document generally indicates an "or" relationship between the related objects.

[0114] The phrase "embodiment" mentioned in the description of the embodiments of the present application means that the specific features, structures, or characteristics described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it refer to independent or alternative embodiments that are mutually exclusive with other embodiments. It is understood explicitly and implicitly by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0115] With the increasing severity of global environmental issues, more and more renewable energy generation systems (such as photovoltaic systems) are being integrated into power systems to reduce carbon emissions from electricity production. As shown in Figure 1, renewable energy generation systems are typically connected to the AC grid through converters. Although converters offer the advantage of fast response, they are static components and lack the rotational inertia and damping characteristics of traditional synchronous generators. Therefore, they cannot provide inertial and damping support for the power system. Therefore, the integration of renewable energy generation systems significantly reduces the power system's inertia, thereby weakening its anti-interference capabilities and reducing its stability.

[0116] Virtual synchronous generator (VSG) technology was developed to address the low inertia level problem caused by the grid connection of such renewable energy power generation systems. It embeds the mathematical model of a traditional synchronous generator into the control algorithm of the converter and utilizes the characteristics of the energy storage system that can provide virtual inertia and virtual damping. The energy storage system is connected to the DC transmission system for VSG control, so that the grid-connected system composed of the converter and the energy storage system can simulate the rotational inertia and damping characteristics of a traditional synchronous generator, allowing the renewable energy power generation system to be connected to the grid in the same way as a traditional synchronous generator, realizing power exchange between the renewable energy power generation system and the AC power grid according to the characteristics of a traditional synchronous generator, thereby improving the stability of the power system.

[0117] Converters can generally be divided into voltage source converters (VSCs) and current source converters (CSCs). Since CSCs provide weak support for power system voltage and frequency, VSCs are generally used as converters in power systems.

[0118] The grid-connected system consisting of a VSC and an energy storage system can provide functions such as inertia support, primary frequency regulation, and static synchronous compensator (STATCOM) for the AC power grid.

[0119] The inertia support function is used to maintain grid frequency stability in the event of an AC grid fault or load change. Specifically, in the event of an AC grid fault or load change, the inertia characteristics of a traditional synchronous generator can be simulated by controlling the charging and discharging of the energy storage system in the grid-connected system. This injects or absorbs energy into or from the AC grid to maintain grid frequency stability.

[0120] The primary frequency regulation function is used to quickly restore the grid frequency when the grid frequency changes instantaneously by controlling the energy storage system to inject power into or absorb power from the AC grid, so as to maintain the grid frequency within the rated range.

[0121] The STATCOM function is used to regulate the reactive power of the AC grid and maintain grid voltage stability. Specifically, the VSC in a grid-connected system can regulate the reactive power of the AC grid and maintain grid voltage stability by converting the DC voltage on the DC side into an AC voltage with the amplitude, frequency, or phase required by the AC grid.

[0122] It can be seen that when a grid-connected system consisting of a VSC and an energy storage system provides inertia support or primary frequency regulation for the AC grid, the VSC and the energy storage system need to work closely together. Specifically, the VSC needs to execute the VSG control algorithm, and the energy storage system needs to execute the constant DC voltage control algorithm to jointly achieve inertia support or primary frequency regulation for the AC grid. When the energy storage system is forced to exit the power system due to maintenance or failure, the VSC itself cannot provide inertia support and primary frequency regulation for the AC grid and can only provide STATCOM functions for the AC grid. In this case, the VSC needs to execute the constant DC voltage and constant reactive power control algorithms to independently assume the reactive power regulation or voltage regulation of the AC grid.

[0123] As can be seen from this, when the energy storage system exits the power system, the VSC needs to switch from the VSG control algorithm to the constant DC voltage and constant reactive power control algorithm. When the energy storage system is reconnected to the power system, the VSC needs to switch from the constant DC voltage and constant reactive power control algorithm to the VSG control algorithm. Because the VSG control algorithm and the constant DC voltage and constant reactive power control algorithm have different state variables and control principles, when the VSC switches between these two algorithms, it can cause transient shocks such as overcurrent or overvoltage in the AC grid, leading to oscillation and instability in the power system.

[0124] In order to solve the problem of transient impact on the AC power grid caused by the VSC in the grid-connected system when switching the control algorithm, the embodiment of the present application provides an operation control method, device and converter of the converter in the grid-connected system. By setting the initial value of the target state variable in the second control algorithm to the actual value of the corresponding target electrical parameter before switching the control algorithm from the first control algorithm to the second control algorithm, the initial value of the target state variable in the second control algorithm can be kept consistent with the actual value of the corresponding target electrical parameter in the power system after switching to the second control algorithm. In this way, smooth switching of the control algorithm can be achieved, the transient impact on the power grid caused by the converter when switching between different control algorithms can be reduced, and the stability of the power system can be improved.

[0125] Please refer to Figure 2, which is a schematic diagram of the grid-connected system architecture applicable to a method for controlling the operation of a converter in a grid-connected system provided in an embodiment of the present application. The grid-connected system 20 can be connected between a renewable energy generation system 21 and an AC power grid 22 in a power system to provide inertia support, primary frequency regulation, and STATCOM functions for the AC power grid.

[0126] It should be noted that, for the specific meanings of the functions such as inertia support, primary frequency modulation and STATCOM, please refer to the relevant descriptions in the aforementioned embodiments, which will not be repeated here.

[0127] Specifically, the grid-connected system 20 may include an inverter 201 and an energy storage system 202 .

[0128] The AC end of the converter 201 can be connected to the AC grid 22, and the DC end of the converter 201 can be connected to the renewable energy generation system 21 via a DC bus. The energy storage system 202 can be connected in parallel to the DC bus.

[0129] Exemplarily, the converter 201 may be a VSC.

[0130] Specifically, the converter 201 may include a converter module 2011 and a converter operation control device 2012 .

[0131] The converter module 2011 can be used to realize the mutual conversion between alternating current and direct current.

[0132] Exemplarily, the converter module 2011 may include three bridge arms corresponding to three different phases of the AC power, and the three bridge arms may be connected in parallel to the DC bus. Optionally, each bridge arm may include an upper bridge arm and a lower bridge arm connected in series, and the common point of the upper bridge arm and the lower bridge arm of each bridge arm may be connected to the corresponding AC phase line.

[0133] Each upper bridge arm or lower bridge arm may include a bridge arm resistor R, a bridge arm inductor L connected in series, and at least one power module 20110. The power module 20110 may include, for example, switching devices such as a switch tube and / or a diode.

[0134] Exemplarily, the operation control device 2012 of the converter may be a programmable logic controller (PLC) or a microcontroller unit (MCU), etc. The embodiment of the present application does not specifically limit the specific type of the operation control device 2012 of the converter.

[0135] Optionally, the input end of the converter operation control device 2012 can be connected to an electrical parameter acquisition device (such as 23 in FIG. 2 ) and a host computer (not shown) of the power system. Based on this, the converter operation control device 2012 can obtain the actual value of the preset electrical parameter of the power system collected by the electrical parameter acquisition device, or obtain the set value of the preset electrical parameter of the power system from the host computer.

[0136] For example, the input end of the inverter operation control device 2012 can be connected to the electrical parameter acquisition device and the power system host computer via a power line. Alternatively, the inverter operation control device 2012 can be connected to the power system host computer wirelessly via Bluetooth or wireless fidelity (WIFI).

[0137] The term "electrical parameter" refers to the actual electrical parameters present during the operation of the power system. The type of preset electrical parameters can be determined based on the actual control requirements of the power system. For example, the preset electrical parameters may include grid voltage, grid frequency, DC bus voltage, and / or grid current.

[0138] The grid voltage refers to the AC voltage of the AC grid in the power system.

[0139] The grid voltage may include a three-phase AC voltage, for example, an A-phase AC voltage, a B-phase AC voltage, and a C-phase AC voltage. Based on this, the actual value Vg of the grid voltage may include an actual value vgA of the A-phase AC voltage, an actual value vgB of the B-phase AC voltage, and an actual value vgC of the C-phase AC voltage.

[0140] Grid frequency refers to the periodic frequency of changes in the AC voltage of the AC grid in the power system.

[0141] Grid current refers to the AC current of the AC grid in the power system.

[0142] The grid current may include three-phase AC current, for example, phase A, phase B, and phase C. Based on this, the actual value Ig of the grid current may include the actual value igA of the phase A AC current, the actual value igB of the phase B AC current, and the actual value igC of the phase C AC current.

[0143] Optionally, the output end of the inverter operation control device 2012 can be connected to each power module 20110 in the inverter 201. Based on this, the inverter operation control device 2012 can realize operation control of the inverter 201 (such as control of the output power of the inverter 201) by controlling the switching of each power module 20110.

[0144] Specifically, the converter operation control device 2012 can implement operation control of the converter 201 by executing the converter operation control method provided in the embodiment of the present application. It should be noted that the specific content of the converter operation control method will be introduced below and will not be described in detail here.

[0145] Please refer to Figure 3, which is a schematic flow chart of a method for controlling the operation of a converter in a grid-connected system provided by an embodiment of the present application. The execution subject of the method for controlling the operation of the converter may be the operation control device 2012 of the converter described above. The method for controlling the operation of the converter may include S301, which is described in detail as follows:

[0146] S31 , during the execution of the first control algorithm, if a first working mode switching instruction is received, an actual value of a target electrical parameter of the power system is obtained; the target electrical parameter corresponds to a target state variable in the second control algorithm.

[0147] The first control algorithm may be a VSG algorithm.

[0148] It should be noted that when the operation control device of the converter runs the first control algorithm, the grid-connected system operates in the first operation mode. The first operation mode is a mode in which the converter and the energy storage system in the grid-connected system work in coordination.

[0149] The first working mode switching instruction may be sent by a host computer of the power system to the operation control device of the converter.

[0150] Optionally, the first operating mode switching instruction may be used to instruct the grid-connected system to switch from the first operating mode to the second operating mode, wherein the second operating mode is a mode in which the converter in the grid-connected system operates independently.

[0151] Optionally, the first operating mode switching instruction may also be used to control the operation control device of the converter to switch from a first control mode to a second control mode. The first control mode may be a VSG control mode. The second control mode may be a control mode combining constant DC voltage control with constant reactive power control; or, the second control mode may be a control mode combining constant DC voltage control with VSG control.

[0152] Based on this, the second control algorithm may include a constant DC voltage control algorithm and a constant reactive power control algorithm; or, the second control algorithm may include a constant DC voltage control algorithm and a VSG control algorithm.

[0153] The first control mode corresponds to the first control algorithm, and the second control mode corresponds to the second control algorithm. That is, the operation control device of the converter needs to run the first control algorithm when the first control mode is used to control the operation of the converter, and needs to run the second control algorithm when the second control mode is used to control the operation of the converter.

[0154] In the embodiment of the present application, the type of the target electrical parameter can be determined according to the type of the target state variable in the second control algorithm, that is, the target electrical parameter can correspond to the target state variable in the second control algorithm.

[0155] The target state variable is a virtual control parameter used to control the corresponding target electrical parameter in the power system.

[0156] It is understandable that, because different control algorithms are used to achieve different controls on the converter, the types of target state variables in different control algorithms may vary. For example, assuming that the second control algorithm includes an active current state variable for controlling the first active component of the grid current, upon receiving the first operating mode switching instruction, the operation control device of the converter may obtain the actual value of the active component of the grid current at the current moment.

[0157] S32, stop running the first control algorithm, set the initial value of the target state variable in the second control algorithm to the actual value of the corresponding target electrical parameter, and start running the second control algorithm.

[0158] It can be understood that the operation control device of the converter can switch from the first control algorithm to the second control algorithm by stopping running the first control algorithm and starting running the second control algorithm, thereby realizing the switch from providing inertial support or primary frequency regulation function for the AC power grid to providing STATCOM function for the AC power grid.

[0159] The initial value of the target state variable refers to the value of the target state variable at the time of starting to run the second control algorithm, that is, the value of the target state variable at the time of switching from the first control algorithm to the second control algorithm.

[0160] For example, assuming that the target state variable in the second control algorithm includes a first active current state quantity, the operation control device of the converter can set the initial value of the first active current state quantity in the second control algorithm to the actual value of the active component of the grid current before starting to run the second control algorithm before switching from the first control algorithm to the second control algorithm. Thereafter, the operation control device of the converter starts to run the second control algorithm again.

[0161] From the above, it can be seen that the operation control method of the converter provided in the embodiment of the present application, by setting the initial value of the target state variable in the second control algorithm to the actual value of the corresponding target electrical parameter before switching the control algorithm from the first control algorithm to the second control algorithm, can make the initial value of the target state variable in the second control algorithm consistent with the actual value of the corresponding target electrical parameter in the power system after switching to the second control algorithm. In this way, smooth switching of the control algorithm can be achieved, the transient impact on the power grid caused by the converter when switching between different control algorithms is reduced, and the stability of the power system is improved.

[0162] In one embodiment of the present application, when the second control algorithm includes a constant DC voltage control algorithm and a constant reactive power control algorithm, the process of obtaining the actual value of the target electrical parameter of the power system in S31 may include:

[0163] The actual value of the active component and the actual value of the reactive component of the grid current of the power system at the first moment are obtained.

[0164] Correspondingly, the process of setting the initial value of the target state variable to the actual value of the corresponding target electrical parameter in S32 may include the following steps:

[0165] Setting the initial value of the first active current state quantity in the second control algorithm to the actual value of the active component of the grid current at the first moment;

[0166] The initial value of the first reactive current state variable in the second control algorithm is set to the actual value of the reactive component of the grid current at the first moment.

[0167] The first moment is the moment when the operation control device of the converter receives the first working mode switching instruction.

[0168] The actual values ​​of the active component and the reactive component of the grid current at the first moment can be obtained by coordinate transformation of the actual value igA of the A-phase AC current, the actual value igB of the B-phase AC current, and the actual value igC of the C-phase AC current collected by the electrical parameter acquisition device at the first moment.

[0169] Optionally, the above coordinate transformation operation may be performed by an operation control device of the converter.

[0170] Based on this, the operation control device of the converter can obtain the actual value igA of the A-phase AC current, the actual value igB of the B-phase AC current, and the actual value igC of the C-phase AC current collected by the electrical parameter acquisition device at the first moment from the electrical parameter acquisition device, and perform coordinate transformation on the actual value igA of the A-phase AC current, the actual value igB of the B-phase AC current, and the actual value igC of the C-phase AC current at the first moment to obtain the actual value of the active component and the actual value of the reactive component of the grid current at the first moment.

[0171] Among them, the first active current state quantity can be an active current state quantity obtained based on a constant DC voltage control algorithm. The first active current state quantity can be used to control the flow direction of active power in the power system. Specifically, the positive or negative value of the first active current state quantity is used to determine whether the converter absorbs active power from the AC power grid or injects active power into the AC power grid. For example, when the value of the first active current state quantity is positive, it means that the converter absorbs active power from the AC power grid; when the value of the first active current state quantity is negative, it means that the converter injects active power into the AC power grid. Therefore, the grid frequency can be regulated by controlling the value of the first active current state quantity.

[0172] The initial value of the first active current state quantity refers to the value of the first active current state quantity at the moment when the operation control device of the converter starts to execute the second control algorithm.

[0173] Among them, the first active current state quantity can be a reactive current state quantity obtained based on a fixed reactive power control algorithm. The first reactive current state quantity can be used to control the flow direction of reactive power in the power system. Specifically, the positive or negative value of the first reactive current state quantity is used to determine whether the converter absorbs reactive power from the AC power grid or injects reactive power into the AC power grid. For example, when the value of the first reactive current state quantity is positive, it means that the converter absorbs reactive power from the AC power grid; when the value of the first reactive current state quantity is negative, it means that the converter injects reactive power into the AC power grid. Therefore, the grid voltage can be regulated by controlling the value of the first reactive current state quantity.

[0174] The initial value of the first reactive current state quantity refers to the value of the first reactive current state quantity at the moment when the operation control device of the converter starts to run the second control algorithm.

[0175] In this embodiment, when the second control algorithm includes a constant DC voltage control algorithm and a constant reactive power control algorithm, since the target state variables in the second control algorithm include a first active current state quantity and a first reactive current state quantity, when switching from the first control algorithm to the second control algorithm, the initial value of the first active current state quantity and the initial value of the first reactive current state quantity are respectively set to the actual value of the active component and the actual value of the reactive component of the grid current before switching the algorithm, thereby maintaining the continuity of the DC bus voltage and the DC bus current of the power system before and after the control algorithm is switched, thereby reducing the transient impact on the AC power grid.

[0176] Based on this, after starting to run the second control algorithm, the operation control method of the converter may further include S41 to S43 as shown in FIG4 , which are described in detail as follows:

[0177] S41, determining a reference value of a first active current state quantity and a reference value of a first reactive current state quantity at a second moment.

[0178] The reference value of the first active current state quantity may refer to the value of the first active current state quantity after the second control algorithm is executed (i.e., the second control algorithm is effective). The reference value of the first reactive current state quantity may refer to the value of the first reactive current state quantity after the second control algorithm is executed.

[0179] In a specific implementation, S41 may include the following steps:

[0180] 41-1, obtaining a setting value of the DC bus voltage of the power system and a setting value of the reactive power of the AC power grid.

[0181] 41-2, obtaining the actual value of the DC bus voltage and the actual value of the reactive power of the AC grid at the second moment.

[0182] 41-3. Calculate a reference value of the first active current state quantity at the second moment based on the set value of the DC bus voltage and the actual value of the DC bus voltage at the second moment.

[0183] 41-4, calculating a reference value of a first reactive current state quantity based on a set value of reactive power of the AC power grid and an actual value of reactive power of the AC power grid at a second moment.

[0184] The setting value of the DC bus voltage of the power system and the setting value of the reactive power of the AC power grid may both be sent from the upper computer of the power system to the operation control device of the converter.

[0185] Optionally, the operation control device of the converter may obtain from the electric parameter acquisition device an actual value of the DC bus voltage acquired by the electric parameter acquisition device at the second moment.

[0186] Optionally, the actual value of the reactive power of the AC power grid can be obtained by performing power calculation based on the actual value vgA of the AC voltage of phase A, the actual value vgB of the AC voltage of phase B, and the actual value vgC of the AC voltage of phase C, and the actual value igA of the AC current of phase A, the actual value igB of the AC current of phase B, and the actual value igC of the AC current of phase C, collected by the electrical parameter collection device at the second moment. Exemplarily, this power calculation operation can be performed by the operation control device of the converter.

[0187] Based on this, the operation control device of the converter can obtain from the electrical parameter acquisition device the actual value vgA of the A-phase AC voltage, the actual value vgB of the B-phase AC voltage, and the actual value vgC of the C-phase AC voltage, the actual value igA of the A-phase AC current, the actual value igB of the B-phase AC current, and the actual value igC of the C-phase AC current collected by the electrical parameter acquisition device at the second moment, and perform power calculation on the actual value vgA of the A-phase AC voltage, the actual value vgB of the B-phase AC voltage, and the actual value vgC of the C-phase AC voltage, the actual value igA of the A-phase AC current, the actual value igB of the B-phase AC current, and the actual value igC of the C-phase AC current at the second moment to obtain the actual value of the reactive power of the AC power grid.

[0188] Specifically, the operation control device of the converter can calculate the reference value of the first active current state quantity based on the set value of the DC bus voltage and the actual value of the DC bus voltage at the second moment using the following formula (1):

[0189] in, is the reference value of the first active current state quantity, Gvdc(s) is the transfer function of the first proportional integral (PI) regulator for controlling the DC bus voltage, vdcset is the set value of the DC bus voltage, and vdc is the actual value of the DC bus voltage at the second moment.

[0190] The operation control device of the converter can calculate the reference value of the first reactive current state quantity based on the set value of the reactive power of the AC power grid and the actual value of the reactive power of the AC power grid at the second moment using the following formula (2):

[0191] in, is the reference value of the first reactive current state quantity, GQ(s) is the transfer function of the second PI regulator for controlling the reactive power of the AC power grid, Qset is the set value of the reactive power of the AC power grid, and Q is the actual value of the reactive power of the AC power grid at the second moment.

[0192] S42: Acquire an actual value of the active component and an actual value of the reactive component of the grid current at a second moment.

[0193] It should be noted that, for the specific method of obtaining the actual value of the active component and the actual value of the reactive component of the grid current, reference may be made to the relevant description in the aforementioned embodiment, which will not be repeated here.

[0194] S43, based on the reference value of the first active current state quantity, the reference value of the first reactive current state quantity, the actual value of the active component of the grid current and the actual value of the reactive component of the grid current at the second moment, determine the value of the active component and the value of the reactive component of the output potential of the converter at the second moment; the value of the active component and the value of the reactive component of the output potential of the converter at the second moment are used to control the grid voltage of the power system.

[0195] The active component of the output potential of the converter at the second moment is used to adjust the active component of the grid voltage.

[0196] At the second moment, the reactive component of the output potential of the converter is used to regulate the reactive component of the grid voltage.

[0197] Specifically, the operation control device of the converter can determine the value of the active component and the value of the reactive component of the output potential of the converter at the second moment based on the reference value of the first active current state quantity, the reference value of the first reactive current state quantity, the actual value of the active component of the grid current, and the actual value of the reactive component of the grid current using the following formulas (3) and (4):

[0198] Wherein, ed is the value of the active component of the output potential of the converter, eq is the value of the reactive component of the output potential of the converter, Gid(s) is the transfer function of the third PI regulator for controlling the active component of the grid current, is the reference value of the first active current state quantity, is the reference value of the first reactive current state quantity, Giq(s) is the transfer function of the fourth PI regulator for controlling the componentless grid current, igd is the actual value of the active component of the grid current, and igq is the actual value of the reactive component of the grid current.

[0199] In a specific implementation, the process of controlling the grid voltage based on the values ​​of the active component and the reactive component of the output potential of the converter in S43 may include the following steps:

[0200] Modulating a switch control signal based on the value of the active component and the value of the reactive component of the output potential of the converter to obtain a switch modulation signal for controlling each power module in the converter;

[0201] Output switching modulation signals to each power module in the converter.

[0202] In this embodiment, the value of the active component and the value of the reactive component of the output potential of the converter at the second moment are determined during the operation of the second control algorithm. Since the value of the active component and the value of the reactive component of the output potential of the first converter at the second moment are used to control the grid voltage of the power system, the value of the active component and the value of the reactive component of the output potential of the converter can be modulated to obtain a switch modulation signal for controlling the switch module in the converter. The switch modulation signal can be used to control the switching of the power module in the converter, thereby realizing the control of the grid voltage and further realizing the regulation of the reactive power of the AC grid.

[0203] Optionally, after starting to run the second control algorithm, the operation control method of the converter may further include S44 to S48 as shown in FIG4 , which are described in detail as follows:

[0204] S44: Determine a reference value of the active power state quantity and a reference value of the reactive power state quantity at the second moment.

[0205] The active power state quantity corresponds to the active power of the AC power grid in an actual power system, while the reactive power state quantity corresponds to the reactive power of the AC power grid. In other words, the active power state quantity is used to control the active power of the AC power grid in an actual power system, while the reactive power state quantity is used to control the reactive power of the AC power grid in an actual power system.

[0206] In a specific implementation, S44 may include the following steps:

[0207] 44-1, obtaining the actual value of the active component and the actual value of the reactive component of the grid voltage at the second moment.

[0208] 44-2, based on the reference value of the first active current state quantity, the reference value of the first reactive current state quantity, the actual value of the active component of the grid voltage, and the actual value of the reactive component of the grid voltage at the second moment, determine the reference value of the active power state quantity and the reference value of the reactive power state quantity at the second moment.

[0209] Among them, the actual value of the active component and the actual value of the reactive component of the grid voltage at the second moment can be obtained by coordinate transformation of the actual value vgA of the A-phase AC voltage, the actual value vgB of the B-phase AC voltage, and the actual value vgC of the C-phase AC voltage collected by the electrical parameter acquisition device at the second moment.

[0210] Exemplarily, the above-mentioned coordinate transformation operation can be performed by the operation control device of the converter. Based on this, the operation control device of the converter can obtain the actual value vgA of the AC voltage of phase A, the actual value vgB of the AC voltage of phase B, and the actual value vgC of the AC voltage of phase C collected by the electrical parameter acquisition device at the second moment, and perform coordinate transformation on the actual value vgA of the AC voltage of phase A, the actual value vgB of the AC voltage of phase B, and the actual value vgC of the AC voltage of phase C at the second moment to obtain the actual value of the active component and the actual value of the reactive component of the grid voltage at the second moment.

[0211] Specifically, the operation control device of the converter can calculate the reference value of the active power state quantity and the reference value of the reactive power state quantity at the second moment based on the reference value of the first active current state quantity, the reference value of the first reactive current state quantity, the actual value of the active component of the grid voltage, and the actual value of the reactive component of the grid voltage, respectively using the following formulas (5) and (6):

[0212] Among them, PC is the reference value of the active power state quantity, QC is the reference value of the reactive power state quantity, vgd is the actual value of the active component of the grid voltage, vgq is the actual value of the reactive component of the grid voltage, is the reference value of the first active current state quantity, is the reference value of the first reactive current state quantity.

[0213] In another specific implementation, S44 may include the following steps:

[0214] 44-3, obtaining the actual value of the active component of the grid voltage, the actual value of the reactive component of the grid voltage, the actual value of the active component of the grid current, and the actual value of the reactive component of the grid current at the second moment.

[0215] 44-4, based on the actual value of the active component of the grid voltage at the second moment, the actual value of the reactive component of the grid voltage, the actual value of the active component of the grid current, and the actual value of the reactive component of the grid current, determine the reference value of the active power state quantity and the reference value of the reactive power state quantity at the second moment.

[0216] It should be noted that the specific method for obtaining the actual value of the active component of the grid voltage, the actual value of the reactive component of the grid voltage, the actual value of the active component of the grid current, and the actual value of the reactive component of the grid current can be referred to the relevant description in the aforementioned embodiment and will not be repeated here.

[0217] Specifically, the operation control device of the converter can calculate the reference value of the active power state quantity and the reference value of the reactive power state quantity in the second control algorithm based on the actual value of the active component of the grid voltage, the actual value of the reactive component of the grid voltage, the actual value of the active component of the grid current, and the actual value of the reactive component of the grid current at the second moment using the following formula (7) and formula (8): C =1.5(v gd ×i gd +v gq ×i gq ); Formula (7) Q C =1.5(-v gd ×i gq +v gq ×i gd ); Formula (8)

[0218] Among them, PC is the reference value of the active power state quantity, QC is the reference value of the reactive power state quantity, vgd is the actual value of the active component of the grid voltage, vgq is the actual value of the reactive component of the grid voltage, igd is the actual value of the active component of the grid current, and igq is the actual value of the reactive component of the grid current.

[0219] S45: Determine the feedback value of the active power state quantity and the feedback value of the reactive power state quantity at the second moment; the feedback value of the active power state quantity and the feedback value of the reactive power state quantity are related to the reference value of the second active current state quantity and the reference value of the second reactive current state quantity in the first control algorithm.

[0220] The feedback value of the active power state quantity may be used to reflect the difference between the reference value of the active power state quantity and the actual value of the active power of the AC power grid.

[0221] The feedback value of the reactive power state quantity can be used to reflect the difference between the reference value of the reactive power state quantity and the actual value of the reactive power of the AC power grid.

[0222] In a specific implementation, S45 may include the following steps:

[0223] 45-1, obtaining the actual value of the active component and the actual value of the reactive component of the grid voltage at the second moment.

[0224] 45-2, based on the reference value of the second active current state quantity at the second moment, the reference value of the second reactive current state quantity, the actual value of the active component of the grid voltage, and the actual value of the reactive component of the grid voltage, calculate the feedback value of the active power state quantity and the feedback value of the reactive power state quantity at the second moment.

[0225] It should be noted that, for the specific method of obtaining the actual value of the active component of the grid voltage and the actual value of the reactive component of the grid voltage, reference may be made to the relevant description in the aforementioned embodiment, which will not be repeated here.

[0226] Specifically, the operation control device of the converter can calculate the feedback value of the active power state quantity and the feedback value of the reactive power state quantity at the second moment based on the reference value of the second active current state quantity, the reference value of the second reactive current state quantity, the actual value of the active component of the grid voltage, and the actual value of the reactive component of the grid voltage using the following formulas (9) and (10):

[0227] Among them, PV is the feedback value of the active power state quantity, QV is the feedback value of the reactive power state quantity, vgd is the actual value of the active component of the grid voltage, and vgq is the actual value of the reactive component of the grid voltage. is the reference value of the second active current state quantity, is the reference value of the second reactive current state quantity.

[0228] S46 , obtaining an actual value of the grid voltage, an actual value of the active component of the grid voltage, an actual value of the reactive component of the grid voltage, and an actual value of the grid frequency at the second moment.

[0229] The actual value of the grid voltage may refer to the actual value of the amplitude of the grid voltage.

[0230] Optionally, the operation control device of the converter may obtain from the electric parameter acquisition device an actual value of the grid voltage and an actual value of the grid frequency acquired by the electric parameter acquisition device at the second moment.

[0231] It should be noted that, for the specific method of obtaining the actual value of the active component and the actual value of the reactive component of the grid voltage, reference may be made to the relevant description in the aforementioned embodiment, which will not be repeated here.

[0232] S47, obtaining a setting value of the grid frequency and a setting value of the grid voltage.

[0233] Optionally, the setting value of the grid frequency and the setting value of the grid voltage may be sent from a host computer of the power system to the operation control device of the converter.

[0234] S48, based on the reference value of the active power state quantity at the second moment, the reference value of the reactive power state quantity, the feedback value of the active power state quantity, the feedback value of the reactive power state quantity, the actual value of the grid voltage, the actual value of the active component of the grid voltage, the actual value of the reactive component of the grid voltage, the actual value of the grid frequency, the set value of the grid frequency, the set value of the grid voltage and the rated value of the grid frequency, adjust the reference value of the second active current state quantity and the reference value of the second reactive current state quantity.

[0235] Specifically, the operation control device of the converter can determine the reference value of the second active current state quantity and the reference value of the second reactive current state quantity based on the reference value of the active power state quantity at the second moment, the reference value of the reactive power state quantity, the feedback value of the active power state quantity, the feedback value of the reactive power state quantity, the actual value of the grid voltage, the actual value of the active component of the grid voltage, the actual value of the reactive component of the grid voltage, the actual value of the grid frequency, the set value of the grid frequency, the set value of the grid voltage, and the rated value of the grid frequency using the following formulas (11) and (12):

[0236]

[0237] Wherein, K is the integral coefficient of the reactive loop when the VSC executes the VSG control algorithm, s is the Laplace operator, QC is the reference value of the reactive power state quantity, QV is the feedback value of the reactive power state quantity, Dp is the virtual damping coefficient of the grid-connected system, PC is the reference value of the active power state quantity, PV is the feedback value of the active power state quantity, J is the virtual moment of inertia of the grid-connected system, Vset is the set value of the grid voltage, Vg is the actual value of the grid voltage, ωset is the set value of the grid frequency, and ωg is the actual value of the grid frequency.

[0238] It should be noted that the virtual damping coefficient Dp and the virtual moment of inertia J of the grid-connected system can be determined according to the actual operating conditions and control requirements of the power system, and their specific values ​​are not restricted here.

[0239] The rated value ωn of the grid frequency may be, for example, 50 Hz or 60 Hz.

[0240] In this embodiment, after the second control algorithm starts to run, the feedback value of the active power state quantity and the feedback value of the reactive power state quantity are determined based on the actual value of the active component and the actual value of the reactive component of the grid voltage, and based on the feedback value of the active power state quantity, the feedback value of the reactive power state quantity and the actual values ​​of each power parameter in the power system, the reference value of the second active current state quantity and the reference value of the second reactive current state quantity in the first control algorithm are adjusted, so that the reference value of the second active current state quantity and the reference value of the second reactive current state quantity in the first control algorithm can always be consistent with the actual values ​​of the corresponding power parameters in the actual power system. In this way, the converter can also achieve smooth switching when switching from the second control algorithm to the first control algorithm, further reducing the transient impact of the algorithm switching on the power grid and improving the stability of the power system.

[0241] In this embodiment, the operation control method of the converter may further include S51 to S54 as shown in FIG5 , which are described in detail as follows:

[0242] S51, in the process of running the first control algorithm, obtain the actual value of the active power of the power system, the actual value of the reactive power, the actual value of the grid frequency, the actual value of the grid voltage, the actual value of the active component of the grid voltage, the actual value of the reactive component of the grid voltage, the actual value of the active component of the grid current, and the actual value of the reactive component of the grid current at the third moment.

[0243] The third moment may be any moment after the first control algorithm is executed.

[0244] It should be noted that the specific method for obtaining the actual value of active power, the actual value of reactive power, the actual value of the grid voltage, the actual value of the active component of the grid voltage, the actual value of the reactive component of the grid voltage, the actual value of the active component of the grid current, and the actual value of the reactive component of the grid current can be referred to the relevant description in the aforementioned embodiments and will not be repeated here.

[0245] S52, obtaining a setting value of active power, a setting value of reactive power, a setting value of grid frequency, and a setting value of grid voltage.

[0246] The set value of active power, the set value of reactive power, the set value of grid frequency and the set value of grid voltage may all be sent from the upper computer of the power system to the operation control device of the converter.

[0247] S53, based on the actual value of active power, the actual value of reactive power, the actual value of grid frequency, the actual value of grid voltage, the actual value of the active component of grid voltage, the actual value of the reactive component of grid voltage, the set value of active power, the set value of reactive power, the set value of grid frequency and the set value of grid voltage at the third moment, determine the reference value of the second active current state quantity and the reference value of the second reactive current state quantity at the third moment.

[0248] Specifically, the operation control device of the converter can be based on the actual value of active power, the actual value of reactive power, the actual value of grid frequency, the actual value of grid voltage, the actual value of the active component of grid voltage, the actual value of the reactive component of grid voltage, the set value of active power, the set value of reactive power, the set value of grid frequency and the set value of grid voltage at the third moment, using the above formula (11) and arrive:

[0249] Among them, K is the integral coefficient of the reactive loop when the VSC executes the VSG control algorithm, s is the Laplace operator, Qset is the set value of reactive power, Q is the actual value of the reactive power state variable, Dp is the virtual damping coefficient of the grid-connected system, Pset is the set value of active power, P is the actual value of active power, J is the virtual moment of inertia of the grid-connected system, Vset is the set value of the grid voltage, Vg is the actual value of the grid voltage, ωset is the set value of the grid frequency, and ωg is the actual value of the grid frequency.

[0250] S54, based on the reference value of the active current state quantity at the third moment, the reference value of the second reactive current state quantity, the actual value of the active component of the grid current and the actual value of the reactive component of the grid current, determine the value of the active component and the value of the reactive component of the output potential of the converter at the third moment; the value of the active component and the value of the reactive component of the output potential of the converter at the third moment are used to adjust the grid frequency of the power system.

[0251] Specifically, the operation control device of the converter can determine the value of the active component and the value of the reactive component of the output potential of the converter at the third moment based on the reference value of the active current state quantity at the third moment, the reference value of the second reactive current state quantity, the actual value of the active component of the grid current, and the actual value of the reactive component of the grid current using the following formulas (17) and (18):

[0252] Wherein, ed is the value of the active component of the output potential of the converter, eq is the value of the reactive component of the output potential of the converter, Gid(s) is the transfer function of the third PI regulator for controlling the active component of the grid current, is the reference value of the second active current state quantity, is the reference value of the second reactive current state quantity, Giq(s) is the transfer function of the fourth PI regulator for controlling the componentless grid current, igd is the actual value of the active component of the grid current, and igq is the actual value of the reactive component of the grid current.

[0253] In this embodiment, the value of the active component and the value of the reactive component of the output potential of the converter at the third moment are determined during the operation of the first control algorithm. Since the value of the active component and the value of the reactive component of the output potential of the first converter at the third moment are used to control the grid frequency of the power system, the value of the active component and the value of the reactive component of the output potential of the converter can be modulated to obtain a switching modulation signal for controlling the switching module in the converter. The switching control of the power module in the converter is realized by the switching modulation signal, thereby realizing the regulation of the grid frequency.

[0254] In another embodiment of the present application, when the second control algorithm includes a constant DC voltage control algorithm and a VSG control algorithm, the process of obtaining the actual value of the target electrical parameter of the power system in S31 may include the following steps:

[0255] An actual value of an active component of a grid current of the power system at a first moment is obtained.

[0256] Correspondingly, the process of setting the initial value of the target state variable to the actual value of the corresponding target electrical parameter in step S32 may include the following steps:

[0257] The initial value of the first active current state variable in the second control algorithm is set to the actual value of the active component of the grid current at the first moment.

[0258] The first moment is the moment when the first working mode switching instruction is received.

[0259] It should be noted that, for the specific method of obtaining the actual value of the active component of the grid current, reference may be made to the relevant description in the aforementioned embodiment, which will not be elaborated here.

[0260] Regarding the specific meaning of the first active current state quantity and the specific meaning of the initial value of the first active current state quantity, reference can also be made to the relevant description in the aforementioned embodiment, which will not be repeated here.

[0261] In this embodiment, when the second control algorithm includes a constant DC voltage control algorithm and a VSG algorithm, since the target state variable in the second control algorithm only includes the first active current state quantity, by setting the initial value of the first active current state quantity to the actual value of the active component of the grid current before switching the algorithm when switching from the first control algorithm to the second control algorithm, the DC bus voltage and DC bus current of the power system can be kept continuous before and after the control algorithm is switched, thereby reducing the transient impact on the AC power grid.

[0262] Based on this, after starting to run the second control algorithm, the operation control method of the converter may further include S61 to S64 as shown in FIG6 , which are described in detail as follows:

[0263] S61, determining a reference value of a first active current state quantity at a second moment.

[0264] It should be noted that, for the specific meaning of the reference value of the first active current state quantity, reference can be made to the relevant description in the aforementioned embodiment, which will not be repeated here.

[0265] In a specific implementation, S61 may include the following steps:

[0266] 61-1, obtain the set value of the DC bus voltage of the power system.

[0267] 61-2, obtaining the actual value of the DC bus voltage at the second moment.

[0268] 61-3. Calculate a reference value of the first active current state quantity at the second moment based on the set value of the DC bus voltage and the actual value of the DC bus voltage at the second moment.

[0269] It should be noted that the specific explanation of 61-1 to 61-2 can refer to the relevant description of 41-1 to 41-3 in the above embodiment, which will not be repeated here. That is, the operation control device of the converter can use the above formula (1) to calculate the reference value of the first active current state quantity at the second moment.

[0270] S62: Determine a reference value of a second reactive current state at a second moment.

[0271] It should be noted that, for the specific meaning of the reference value of the second active current state quantity, reference can be made to the relevant description in the aforementioned embodiment, which will not be repeated here.

[0272] In a specific implementation, S62 may include the following steps:

[0273] 62-1, determine a reference value of the active power state quantity at the second moment.

[0274] 62-2, determine the feedback value of the active power state quantity at the second moment.

[0275] 62-3, obtaining the actual value of the reactive power of the power system, the actual value of the active component of the grid voltage, and the actual value of the reactive component of the grid voltage at the second moment.

[0276] 62-4, obtaining the setting value of reactive power, the setting value of grid voltage, and the setting value of grid frequency.

[0277] 62-5, based on the reference value of the active power state quantity at the second moment, the feedback value of the active power state quantity, the actual value of the reactive power, the actual value of the active component of the grid voltage, the actual value of the reactive component of the grid voltage, the set value of the reactive power, the set value of the grid voltage, the set value of the grid frequency and the rated value of the grid frequency, determine the reference value of the second active current state quantity and the reference value of the second reactive current state quantity at the second moment.

[0278] It should be noted that, for the specific meanings of the reference value of the active power state quantity and the feedback value of the active power state quantity, reference may be made to the relevant description in the aforementioned embodiment, which will not be elaborated here.

[0279] Regarding the specific methods for obtaining the actual value of reactive power, the actual value of the active component of the grid voltage, the actual value of the reactive component of the grid voltage, the set value of reactive power, the set value of the grid voltage, and the set value of the grid frequency, please refer to the relevant description in the aforementioned embodiments and will not be repeated here.

[0280] Specifically, the operation control device of the converter can calculate the reference value of the second active current state quantity and the reference value of the second reactive current state quantity at the second moment based on the reference value of the active power state quantity at the second moment, the feedback value of the active power state quantity, the actual value of the reactive power, the actual value of the active component of the grid voltage, the actual value of the reactive component of the grid voltage, the set value of the reactive power, the set value of the grid voltage, the set value of the grid frequency and the rated value of the grid frequency, using the above formulas (11) and (12).

[0281] In this embodiment, the formulas (11) and (12) are and It can be calculated by the following formula (19) and formula (20):

[0282] Among them, K is the integral coefficient of the reactive loop when the VSC executes the VSG control algorithm, s is the Laplace operator, Qset is the set value of reactive power, Q is the actual value of the reactive power state quantity, Dp is the virtual damping coefficient of the grid-connected system, PC is the reference value of the active power state quantity, PV is the feedback value of the active power state quantity, J is the virtual moment of inertia of the grid-connected system, Vset is the set value of the grid voltage, Vg is the actual value of the grid voltage, ωset is the set value of the grid frequency, and ωg is the actual value of the grid frequency.

[0283] In an optional implementation, S62-1 may include the following steps:

[0284] S62-1.1, determine the reference value of the active power state quantity at the second moment based on the reference value of the first active current state quantity at the second moment, the reference value of the second reactive current state quantity, the actual value of the active component of the grid voltage and the actual value of the reactive component of the grid voltage.

[0285] Specifically, the operation control device of the converter can calculate the reference value of the active power state quantity at the second moment based on the reference value of the first active current state quantity at the second moment, the reference value of the second reactive current state quantity, the actual value of the active component of the grid voltage, and the actual value of the reactive component of the grid voltage using the following formula (21):

[0286] Among them, PC is the reference value of the active power state quantity, vgd is the actual value of the active component of the grid voltage, is the reference value of the first active current state quantity, vgq is the actual value of the reactive component of the grid voltage, is the reference value of the second reactive current state quantity.

[0287] In another optional implementation, S62-1 may include the following steps:

[0288] S62-1.2, obtaining an actual value of the active component and the actual value of the reactive component of the grid current at the second moment.

[0289] S62-1.3, determine a reference value of the active power state quantity at the second moment based on the actual value of the active component of the grid voltage, the actual value of the reactive component of the grid voltage, the actual value of the active component of the grid current, and the actual value of the reactive component of the grid current.

[0290] It should be noted that, for the specific method of obtaining the actual value of the active component and the actual value of the reactive component of the grid current, reference may be made to the relevant description in the aforementioned embodiment, which will not be repeated here.

[0291] Specifically, the operation control device of the converter can calculate the reference value of the active power state quantity at the second moment based on the actual value of the active component of the grid voltage, the actual value of the reactive component of the grid voltage, the actual value of the active component of the grid current, and the actual value of the reactive component of the grid current using the following formula (22): P C =1.5(v gd ×i gd +v gq ×i gq ); Formula (22)

[0292] Among them, PC is the reference value of the active power state quantity, vgd is the actual value of the active component of the grid voltage, igd is the actual value of the active component of the grid current, vgq is the actual value of the reactive component of the grid voltage, and igq is the actual value of the reactive component of the grid current.

[0293] In a specific implementation, S63-1 may include the following steps:

[0294] Based on the reference value of the second active current state quantity at the second moment, the reference value of the second reactive current state quantity, the actual value of the active component of the grid voltage and the actual value of the reactive component of the grid voltage, the feedback value of the active power state quantity at the second moment is determined.

[0295] Specifically, the operation control device of the converter can use the above formula (9) to calculate the feedback value of the active power state quantity at the second moment. For the content of formula (9), please refer to the relevant description in the corresponding embodiment and will not be repeated here.

[0296] S63: Acquire an actual value of the active component and an actual value of the reactive component of the grid current at the second moment.

[0297] S64, based on the reference value of the first active current state quantity at the second moment, the reference value of the second reactive current state quantity, the actual value of the active component of the grid current and the actual value of the reactive component of the grid current, determine the value of the active component and the value of the reactive component of the output potential of the converter at the second moment.

[0298] It should be noted that, for the specific meanings of the values ​​of the active component and the reactive component of the output potential, reference may be made to the relevant descriptions in the aforementioned embodiments, which will not be elaborated here.

[0299] Specifically, the operation control device of the converter can calculate the value of the active component and the value of the reactive component of the output potential of the converter at the second moment based on the reference value of the first active current state quantity, the reference value of the second reactive current state quantity, the actual value of the active component of the grid current, and the actual value of the reactive component of the grid current using the following formulas (23) and (24):

[0300] Wherein, ed is the value of the active component of the output potential of the converter, eq is the value of the reactive component of the output potential of the converter, Gid(s) is the transfer function of the third PI regulator for controlling the active component of the grid current, is the reference value of the first active current state quantity, is the reference value of the second reactive current state quantity, Giq(s) is the transfer function of the fourth PI regulator for controlling the componentless grid current, igd is the actual value of the active component of the grid current, and igq is the actual value of the reactive component of the grid current.

[0301] In this embodiment, the value of the active component and the value of the reactive component of the output potential of the converter at the second moment are determined during the operation of the second control algorithm. Since the value of the active component and the value of the reactive component of the output potential of the first converter at the second moment are used to control the grid voltage of the power system, the value of the active component and the value of the reactive component of the output potential of the converter can be modulated to obtain a switching modulation signal for controlling the switching module in the converter. The switching control of the power module in the converter is realized by the switching modulation signal, thereby realizing control of the grid voltage.

[0302] In this embodiment, the operation control method of the converter may further include S71 to S74 as shown in FIG7 , which are described in detail as follows:

[0303] S71. In the process of running the first control algorithm, the actual value of the active power of the power system, the actual value of the reactive power, the actual value of the grid frequency, the actual value of the grid voltage, the actual value of the active component of the grid voltage, the actual value of the reactive component of the grid voltage, the actual value of the active component of the grid current, and the actual value of the reactive component of the grid current at the third moment are obtained.

[0304] The third moment may be any moment after the first control algorithm is executed.

[0305] It should be noted that the specific method for obtaining the actual value of active power, the actual value of reactive power, the actual value of the grid voltage, the actual value of the active component of the grid voltage, the actual value of the reactive component of the grid voltage, the actual value of the active component of the grid current, and the actual value of the reactive component of the grid current can be referred to the relevant description in the aforementioned embodiments and will not be repeated here.

[0306] S72, obtaining a setting value of active power, a setting value of reactive power, a setting value of grid frequency, and a setting value of grid voltage.

[0307] The set value of active power, the set value of reactive power, the set value of grid frequency and the set value of grid voltage may all be sent from the upper computer of the power system to the operation control device of the converter.

[0308] S73, based on the actual value of active power, the actual value of reactive power, the actual value of grid frequency, the actual value of grid voltage, the actual value of the active component of grid voltage, the actual value of the reactive component of grid voltage, the set value of active power, the set value of reactive power, the set value of grid frequency and the set value of grid voltage at the third moment, determine the reference value of the second active current state quantity and the reference value of the second reactive current state quantity at the third moment.

[0309] Specifically, the operation control device of the converter can determine the reference value of the second active current state quantity and the reference value of the second reactive current state quantity at the third moment based on the actual value of the active power, the actual value of the reactive power, the actual value of the grid frequency, the actual value of the grid voltage, the actual value of the active component of the grid voltage, the actual value of the reactive component of the grid voltage, the set value of the active power, the set value of the reactive power, the set value of the grid frequency and the set value of the grid voltage at the third moment, using the above formulas (11) and (12).

[0310] In this embodiment, the formulas (11) and (12) are and It can be calculated using the above formulas (15) and (16).

[0311] S74, based on the reference value of the active current state quantity at the third moment, the reference value of the second reactive current state quantity, the actual value of the active component of the grid current and the actual value of the reactive component of the grid current, determine the value of the active component and the value of the reactive component of the output potential of the converter at the third moment; the value of the active component and the value of the reactive component of the output potential of the converter at the third moment are used to adjust the grid frequency of the power system.

[0312] Specifically, the operation control device of the converter can use the above formulas (17) and (18) to determine the value of the active component and the value of the reactive component of the output potential of the converter at the third moment based on the reference value of the active current state quantity at three moments, the reference value of the second reactive current state quantity, the actual value of the active component of the grid current, and the actual value of the reactive component of the grid current.

[0313] In this embodiment, the value of the active component and the value of the reactive component of the output potential of the converter at the third moment are determined during the operation of the first control algorithm. Since the value of the active component and the value of the reactive component of the output potential of the first converter at the third moment are used to control the grid frequency of the power system, the value of the active component and the value of the reactive component of the output potential of the converter can be modulated to obtain a switching modulation signal for controlling the switching module in the converter. The switching control of the power module in the converter is realized by the switching modulation signal, thereby realizing the regulation of the grid frequency.

[0314] It can be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0315] Based on the inverter operation control method provided in the above embodiment, the present embodiment further provides an embodiment of an inverter operation control device that implements the above method embodiment. Please refer to Figure 8 for a schematic diagram of the structure of a control device provided in the present embodiment. For ease of illustration, only the parts relevant to this embodiment are shown. As shown in Figure 8, the inverter operation control device 80 may include: an acquisition module 801 and a setting module 802. Among them:

[0316] The acquisition module 801 is used to acquire the actual value of the target electrical parameter of the power system if a first working mode switching instruction is received during the operation of the first control algorithm; the target electrical parameter corresponds to the target state variable in the second control algorithm.

[0317] The setting module 802 is used to stop running the first control algorithm, set the initial value of the target state variable to the actual value of the corresponding target electrical parameter, and start running the second control algorithm.

[0318] Optionally, the first control algorithm is a virtual synchronous generator control algorithm, and the second control algorithm includes a constant DC voltage control algorithm and a constant reactive power control algorithm;

[0319] The acquisition module 801 is specifically used for:

[0320] Acquire the actual value of the active component and the actual value of the reactive component of the grid current of the power system at a first moment; the first moment is the moment when the first working mode switching instruction is received.

[0321] The setting module 802 is specifically used for:

[0322] Setting the initial value of the first active current state quantity in the second control algorithm to the actual value of the active component of the grid current at the first moment;

[0323] An initial value of the first reactive current state variable in the second control algorithm is set to the actual value of the reactive component of the grid current at the first moment.

[0324] Optionally, the acquisition module 801 is further configured to acquire an actual value of an active component and an actual value of a reactive component of the grid current at the second moment.

[0325] As shown in FIG. 9 and FIG. 10 , the operation control device 80 of the converter may further include a constant DC voltage and constant reactive power control module 81 and a current inner loop 82 .

[0326] Among them, the constant DC voltage and constant reactive power control module 81 is used to determine the reference value of the first active current state quantity and the reference value of the first reactive current state quantity at the second moment; the second moment is any moment after running the second control algorithm.

[0327] The current inner loop 82 is used to determine the value of the active component and the value of the reactive component of the output potential of the converter at the second moment based on the reference value of the first active current state quantity, the reference value of the first reactive current state quantity, the actual value of the active component of the grid current, and the actual value of the reactive component of the grid current at the second moment; the value of the active component and the value of the reactive component of the output potential of the converter at the second moment are used to control the grid voltage of the power system.

[0328] That is, when the operation control device 80 of the converter runs the second control algorithm, the switches S2 and S4 in FIG. 9 and FIG. 10 are both set to position 1.

[0329] Specifically, as shown in FIG11 and FIG12, the current inner loop 82 can use the above formula (3) and formula (4) to determine the value of the active component and the value of the reactive component of the output potential of the converter at the second moment.

[0330] Optionally, the acquisition module 801 is further configured to acquire an actual value of the grid voltage, an actual value of the active component of the grid voltage, an actual value of the reactive component of the grid voltage, and an actual value of the grid frequency at the second moment.

[0331] As shown in FIG9 and FIG10 , the operation control device 80 of the converter may further include a virtual power instruction calculation module 83 , a virtual power feedback calculation module 84 and a VSG module 85 .

[0332] The virtual power instruction calculation module 83 is used to determine the reference value of the active power state quantity and the reference value of the reactive power state quantity at the second moment.

[0333] The virtual power feedback calculation module 84 is used to determine the feedback value of the active power state quantity and the feedback value of the reactive power state quantity at the second moment; the feedback value of the active power state quantity and the feedback value of the reactive power state quantity are related to the reference value of the second active current state quantity and the reference value of the second reactive current state quantity in the first control algorithm at the second moment.

[0334] The acquisition module 801 is further configured to acquire a setting value of the grid frequency and a setting value of the grid voltage.

[0335] The VSG module 85 is used to adjust the reference value of the second active current state quantity and the reference value of the second reactive current state quantity based on the reference value of the active power state quantity at the second moment, the reference value of the reactive power state quantity, the feedback value of the active power state quantity, the feedback value of the reactive power state quantity, the actual value of the grid voltage, the actual value of the active component of the grid voltage, the actual value of the reactive component of the grid voltage, the actual value of the grid frequency, the set value of the grid frequency, the set value of the grid voltage and the rated value of the grid frequency.

[0336] That is, when the operation control device 80 of the converter runs the second control algorithm, the switch S1 and the switch S3 in FIG. 9 and FIG. 10 are both set to 1.

[0337] Optionally, the acquisition module 801 is further configured to acquire a set value of the DC bus voltage of the power system and a set value of the reactive power of the AC power grid.

[0338] The acquisition module 801 is further configured to acquire an actual value of the DC bus voltage and an actual value of the reactive power of the AC power grid at the second moment.

[0339] As shown in FIG9 and FIG10 , the constant DC voltage and constant reactive power control module 81 may include a DC voltage loop 811 and a reactive power loop 812 .

[0340] The DC voltage loop 811 is configured to calculate a reference value of the first active current state quantity at the second moment based on the set value of the DC bus voltage and the actual value of the DC bus voltage at the second moment.

[0341] Specifically, as shown in FIG11 and FIG12 , the DC voltage loop 811 may use the above formula (1) to calculate the reference value of the first active current state quantity at the second moment.

[0342] The reactive power loop 812 is used to calculate a reference value of the first reactive current state quantity at the second moment based on the set value of the reactive power of the AC power grid and the actual value of the reactive power of the AC power grid at the second moment.

[0343] Specifically, as shown in FIG11 and FIG12 , the reactive power loop 812 may use the above formula (2) to calculate the reference value of the first reactive current state quantity at the second moment.

[0344] Optionally, the acquisition module 801 is further configured to acquire an actual value of an active component and an actual value of a reactive component of the grid voltage at the second moment.

[0345] As shown in Figure 11, the virtual power instruction calculation module 83 is specifically used to determine the reference value of the active power state quantity and the reference value of the reactive power state quantity at the second moment based on the reference value of the first active current state quantity at the second moment, the reference value of the first reactive current state quantity, the actual value of the active component of the grid voltage, and the actual value of the reactive component of the grid voltage.

[0346] Specifically, the virtual power instruction calculation module 83 may use the above formula (5) and formula (6) to calculate the reference value of the active power state quantity and the reference value of the reactive power state quantity at the second moment.

[0347] Optionally, the acquisition module 801 is further used to obtain the actual value of the active component of the grid voltage, the actual value of the reactive component of the grid voltage, the actual value of the active component of the grid current, and the actual value of the reactive component of the grid current at the second moment.

[0348] As shown in Figure 12, the virtual power instruction calculation module 83 is specifically used to determine the reference value of the active power state quantity and the reference value of the reactive power state quantity at the second moment based on the actual value of the active component of the grid voltage at the second moment, the actual value of the reactive component of the grid voltage, the actual value of the active component of the grid current, and the actual value of the reactive component of the grid current.

[0349] Specifically, the virtual power instruction calculation module 83 may use the above formula (7) and formula (8) to calculate the reference value of the active power state quantity and the reference value of the reactive power state quantity at the second moment.

[0350] Optionally, the acquisition module 801 is further configured to acquire an actual value of an active component and an actual value of a reactive component of the grid voltage at the second moment.

[0351] As shown in Figures 11 and 12, the virtual power feedback calculation module 84 is specifically used to calculate the feedback value of the active power state quantity and the feedback value of the reactive power state quantity at the second moment based on the reference value of the second active current state quantity at the second moment, the reference value of the second reactive current state quantity, the actual value of the active component of the grid voltage, and the actual value of the reactive component of the grid voltage.

[0352] Specifically, the virtual power feedback calculation module 84 may use the above formula (9) and formula (10) to calculate the feedback value of the active power state quantity and the feedback value of the reactive power state quantity at the second moment.

[0353] Optionally, the acquisition module 801 is further configured to, during the execution of the first control algorithm, acquire, at a third moment, an actual value of the active power of the power system, an actual value of the reactive power, an actual value of the grid frequency, an actual value of the grid voltage, an actual value of the active component of the grid voltage, an actual value of the reactive component of the grid voltage, an actual value of the active component of the grid current, and an actual value of the reactive component of the grid current;

[0354] The acquisition module 801 is further configured to acquire the set value of the active power, the set value of the reactive power, the set value of the grid frequency, and the set value of the grid voltage.

[0355] As shown in Figures 11 and 12, the VSG module 85 is used to determine the reference value of the second active current state quantity and the reference value of the second reactive current state quantity at the third moment based on the actual value of the active power, the actual value of the reactive power, the actual value of the grid frequency, the actual value of the grid voltage, the actual value of the active component of the grid voltage, the actual value of the reactive component of the grid voltage, the set value of the active power, the set value of the reactive power, the set value of the grid frequency and the set value of the grid voltage.

[0356] That is, when the operation control device 80 of the converter runs the second control algorithm, the switches S1 and S3 in FIG. 9 and FIG. 10 are both set to 0.

[0357] Specifically, the VSG module 85 may use the above formulas (11) to (14) to calculate the reference value of the second active current state quantity and the reference value of the second reactive current state quantity at the third moment.

[0358] In this embodiment, the formulas (11) and (12) are and It can be calculated using the above formulas (15) and (16).

[0359] The current inner loop 82 is used to determine the value of the active component and the value of the reactive component of the output potential of the converter at the third moment based on the reference value of the active current state quantity at the third moment, the reference value of the second reactive current state quantity, the actual value of the active component of the grid current, and the actual value of the reactive component of the grid current; the value of the active component and the value of the reactive component of the output potential of the converter at the third moment are used to adjust the grid frequency of the power system.

[0360] That is, when the operation control device 80 of the converter runs the second control algorithm, the switches S2 and S4 in FIG. 9 and FIG. 10 are turned on.

[0361] Specifically, the current inner loop 82 can use the above formula (17) and formula (18) to calculate the value of the active component and the value of the reactive component of the output potential of the converter at the third moment.

[0362] Optionally, the first control algorithm is a virtual synchronous generator control algorithm, and the second control algorithm includes a constant DC voltage control algorithm and the virtual synchronous generator control algorithm.

[0363] Based on this, the acquisition module 801 is specifically used to obtain the actual value of the active component of the grid current of the power system at the first moment; the first moment is the moment when the first working mode switching instruction is received.

[0364] The setting module 802 is specifically configured to set the initial value of the first active current state variable in the second control algorithm to the actual value of the active component of the grid current at the first moment.

[0365] Optionally, the acquisition module 801 is further configured to acquire an actual value of an active component and an actual value of a reactive component of the grid current at the second moment.

[0366] As shown in FIG. 13 and FIG. 14 , the operation control device 80 of the converter further includes a DC voltage loop 811 , a feedback module, and an inner current loop 82 .

[0367] The DC voltage loop 811 is used to determine a reference value of the first active current state quantity at the second moment.

[0368] The feedback module is used to determine a reference value of the second reactive current state at the second moment.

[0369] The current inner loop 82 is used to determine the value of the active component and the value of the reactive component of the output potential of the converter at the second moment based on the reference value of the first active current state quantity at the second moment, the reference value of the second reactive current state quantity, the actual value of the active component of the grid current, and the actual value of the reactive component of the grid current; the value of the active component and the value of the reactive component of the output potential of the converter at the second moment are used to control the grid voltage of the power system.

[0370] That is, when the operation control device 80 of the converter runs the second control algorithm, the switch S2 in FIG. 13 and FIG. 14 is set to position 1.

[0371] Specifically, as shown in FIG15 and FIG17, the current inner loop 82 can use the above formula (23) and formula (24) to calculate the value of the active component and the value of the reactive component of the output potential of the converter at the second moment.

[0372] Optionally, the acquisition module 801 is further configured to acquire a set value of the DC bus voltage of the power system.

[0373] The acquisition module 801 is further configured to acquire the actual value of the DC bus voltage at the second moment.

[0374] The DC voltage loop 811 is specifically configured to calculate a reference value of the first active current state quantity at the second moment based on the set value of the DC bus voltage and the actual value of the DC bus voltage at the second moment.

[0375] Specifically, as shown in FIG15 and FIG17 , the DC voltage loop 811 may use the above formula (1) to calculate the reference value of the first active current state quantity at the second moment.

[0376] Optionally, the acquisition module 801 is further configured to acquire an actual value of the reactive power of the power system, an actual value of the active component of the grid voltage, and an actual value of the reactive component of the grid voltage at the second moment.

[0377] The acquisition module 801 is further configured to acquire the set value of the reactive power, the set value of the grid voltage, and the set value of the grid frequency.

[0378] The feedback module includes a virtual power instruction calculation module 83 , a virtual power feedback calculation module 84 and a VSG module 85 .

[0379] The virtual power instruction calculation module 83 is used to determine the reference value of the active power state quantity at the second moment.

[0380] The virtual power feedback calculation module 84 is used to determine the feedback value of the active power state quantity at the second moment.

[0381] The VSG module 85 is used to determine the reference value of the second active current state quantity and the reference value of the second reactive current state quantity at the second moment based on the reference value of the active power state quantity at the second moment, the feedback value of the active power state quantity, the actual value of the reactive power, the actual value of the active component of the grid voltage, the actual value of the reactive component of the grid voltage, the set value of the reactive power, the set value of the grid voltage, the set value of the grid frequency and the rated value of the grid frequency.

[0382] That is, when the operation control device 80 of the converter runs the second control algorithm, the switch S0 in FIG. 13 and FIG. 14 is set to position 1.

[0383] Specifically, as shown in FIG15 and FIG16 , the VSG module 85 can calculate the reference value of the second active current state quantity and the reference value of the second reactive current state quantity at the second moment using the above formula (11) and formula (12).

[0384] In this embodiment, the formulas (11) and (12) are and It can be calculated using the above formulas (19) and (20).

[0385] Optionally, as shown in FIG15 , the virtual power instruction calculation module 83 is specifically configured to:

[0386] Based on the reference value of the first active current state quantity at the second moment, the reference value of the second reactive current state quantity, the actual value of the active component of the grid voltage and the actual value of the reactive component of the grid voltage, the reference value of the active power state quantity at the second moment is determined.

[0387] Specifically, the virtual power instruction calculation module 83 can use the above formula (21) to calculate the reference value of the active power state quantity at the second moment.

[0388] Optionally, the acquisition module 801 is further configured to acquire an actual value of an active component and an actual value of a reactive component of the grid current at the second moment.

[0389] The acquisition module 801 is further configured to acquire an actual value of the active component and an actual value of the reactive component of the grid current at the second moment.

[0390] As shown in FIG16 , the virtual power instruction calculation module 83 is specifically used for:

[0391] Based on the actual value of the active component of the grid voltage at the second moment, the actual value of the reactive component of the grid voltage, the actual value of the active component of the grid current, and the actual value of the reactive component of the grid current, the reference value of the active power state quantity at the second moment is determined.

[0392] Specifically, the virtual power instruction calculation module 83 can use the above formula (22) to calculate the reference value of the active power state quantity at the second moment.

[0393] Optionally, the virtual power feedback calculation module 84 is specifically configured to:

[0394] Based on the reference value of the second active current state quantity at the second moment, the reference value of the second reactive current state quantity, the actual value of the active component of the grid voltage and the actual value of the reactive component of the grid voltage, the feedback value of the active power state quantity at the second moment is determined.

[0395] Specifically, as shown in FIG15 and FIG16 , the virtual power feedback calculation module 84 uses the above formula (9) to calculate the feedback value of the active power state quantity at the second moment.

[0396] Optionally, the acquisition module 801 is also used to obtain the actual value of the active power, the actual value of the reactive power, the actual value of the grid frequency, the actual value of the grid voltage, the actual value of the active component of the grid voltage, the actual value of the reactive component of the grid voltage, the actual value of the active component of the grid current, and the actual value of the reactive component of the grid current of the power system at the third moment during the operation of the first control algorithm.

[0397] The acquisition module 801 is further configured to acquire the set value of the active power, the set value of the reactive power, the set value of the grid frequency, and the set value of the grid voltage.

[0398] The VSG module 85 is used to determine the reference value of the second active current state quantity and the reference value of the second reactive current state quantity at the third moment based on the actual value of the active power, the actual value of the reactive power, the actual value of the grid frequency, the actual value of the grid voltage, the actual value of the active component of the grid voltage, the actual value of the reactive component of the grid voltage, the set value of the active power, the set value of the reactive power, the set value of the grid frequency and the set value of the grid voltage at the third moment.

[0399] That is, when the operation control device 80 of the converter runs the second control algorithm, the switch S1 in FIG. 13 and FIG. 14 is set to position 1.

[0400] Specifically, as shown in FIG15 and FIG16 , the VSG module 85 may use the above formula (11) and formula (12) to determine the reference value of the second active current state quantity and the reference value of the second reactive current state quantity at the third moment.

[0401] In this embodiment, the formulas (11) and (12) are and It can be calculated using the above formulas (15) and (16).

[0402] The current inner loop 82 is used to determine the value of the active component and the value of the reactive component of the output potential of the converter at the third moment based on the reference value of the active current state quantity at the third moment, the reference value of the second reactive current state quantity, the actual value of the active component of the grid current, and the actual value of the reactive component of the grid current; the value of the active component and the value of the reactive component of the output potential of the converter at the third moment are used to control the grid frequency of the power system.

[0403] Specifically, as shown in FIG15 and FIG16, the current inner loop 82 uses the above formula (17) and formula (18) to determine the value of the active component and the value of the reactive component of the output potential of the converter at the third moment.

[0404] It should be noted that the information interaction, execution process and other contents between the above-mentioned units are based on the same concept as the method embodiment of this application. Their specific functions and technical effects can be found in the method embodiment part and will not be repeated here.

[0405] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the division of the above-mentioned functional modules / units is used as an example for illustration. In actual applications, the above-mentioned functions can be distributed and completed by different functional modules / units as needed, that is, the internal structure of the control device can be divided into different functional modules / units to complete all or part of the functions described above. The functional modules / units in the embodiment can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional modules / units. In addition, the specific names of the functional modules / units are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of each unit in the above-mentioned control device can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0406] Please refer to Figure 17, which is a structural diagram of an operation control device for a converter provided by another embodiment of the present application. As shown in Figure 17, the operation control device 17 for the converter provided in this embodiment may include: a processor 170, a memory 171, and a computer program 172 stored in the memory 171 and executable on the processor 170, such as a program corresponding to the operation control method for the converter. When the processor 170 executes the computer program 172, the steps in the above-mentioned operation control method embodiment are implemented, such as S31 to S31 shown in Figure 3. Alternatively, when the processor 170 executes the computer program 172, the functions of each module / unit in the above-mentioned control device embodiment are implemented, such as the functions of units 801 to 802 shown in Figure 8.

[0407] Exemplarily, the computer program 172 may be divided into one or more modules / units, one or more of which are stored in the memory 171 and executed by the processor 170 to complete the present application. One or more modules / units may be a series of computer program instruction segments capable of performing specific functions, and the instruction segments are used to describe the execution process of the computer program 172 in the control device 17. For example, the computer program 172 may be divided into an acquisition module and a setting module. The specific functions of each unit can be referred to the relevant description in the embodiment corresponding to FIG. 17 and are not repeated here.

[0408] Those skilled in the art will understand that FIG17 is merely an example of the control device 17 and does not constitute a limitation on the control device 17 , which may include more or fewer components than shown in the figure, or a combination of certain components, or different components.

[0409] The processor 170 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc.

[0410] The memory 171 can be an internal storage unit of the control device 17, such as the hard disk or memory of the control device 17. The memory 171 can also be an external storage device of the control device 17, such as a plug-in hard disk, smart media card (SMC), secure digital (SD) card, or flash card equipped on the control device 17. Furthermore, the memory 171 can include both the internal storage unit of the control device 17 and an external storage device. The memory 171 is used to store computer programs and other programs and data required by the control device. The memory 171 can also be used to temporarily store data that has been output or is about to be output.

[0411] An embodiment of the present application further provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, each step of the operation control method described in the above method embodiment is implemented.

[0412] An embodiment of the present application provides a computer program product. When the computer program product is run on a control device, the control device implements the steps in the above-mentioned various method embodiments.

[0413] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant description of other embodiments.

[0414] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0415] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. A method for controlling the operation of a converter in a grid-connected system, comprising: During the operation of the first control algorithm, if a first working mode switching instruction is received, an actual value of a target electrical parameter of the power system is obtained; The target electrical parameter corresponds to the target state variable in the second control algorithm; The first control algorithm is stopped, the initial value of the target state variable is set to the actual value of the corresponding target electrical parameter, and the second control algorithm is started.

2. The operation control method according to claim 1, wherein: The first control algorithm is a virtual synchronous generator control algorithm, and the second control algorithm includes a constant DC voltage control algorithm and a constant reactive power control algorithm; The obtaining of the actual value of the target electric parameter of the power system includes: Acquire an actual value of an active component and an actual value of a reactive component of a grid current of the power system at a first moment; the first moment being a moment when the first working mode switching instruction is received; The step of setting the initial value of the target state variable to the actual value of the corresponding target electrical parameter comprises: Setting the initial value of the first active current state quantity in the second control algorithm to the actual value of the active component of the grid current at the first moment; An initial value of the first reactive current state quantity in the second control algorithm is set to the actual value of the reactive component of the grid current at the first moment.

3. The operation control method according to claim 2, wherein: After starting to run the second control algorithm, the method further includes: Determine a reference value of the first active current state quantity and a reference value of the first reactive current state quantity at a second moment; the second moment is any moment after the second control algorithm is executed; Acquire an actual value of an active component and an actual value of a reactive component of the grid current at the second moment; Based on the reference value of the first active current state quantity, the reference value of the first reactive current state quantity, the actual value of the active component of the grid current and the actual value of the reactive component of the grid current at the second moment, the value of the active component and the value of the reactive component of the output potential of the converter at the second moment are determined; the value of the active component and the value of the reactive component of the output potential of the converter at the second moment are used to control the grid voltage of the power system.

4. The operation control method according to claim 3, wherein: After starting to run the second control algorithm, the method further includes: Determine a reference value of the active power state quantity and a reference value of the reactive power state quantity at the second moment; Determine a feedback value of the active power state quantity and a feedback value of the reactive power state quantity at the second moment; the feedback value of the active power state quantity and the feedback value of the reactive power state quantity are related to a reference value of a second active current state quantity and a reference value of a second reactive current state quantity in the first control algorithm at the second moment; Obtain the actual value of the grid voltage, the actual value of the active component of the grid voltage, and the reactive power of the grid voltage at the second moment. The actual value of the power component and the actual value of the grid frequency; Acquiring a setting value of the grid frequency and a setting value of the grid voltage; Based on the reference value of the active power state quantity at the second moment, the reference value of the reactive power state quantity, the feedback value of the active power state quantity, the feedback value of the reactive power state quantity, the actual value of the grid voltage, the actual value of the active component of the grid voltage, the actual value of the reactive component of the grid voltage, the actual value of the grid frequency, the set value of the grid frequency, the set value of the grid voltage and the rated value of the grid frequency, the reference value of the second active current state quantity and the reference value of the second reactive current state quantity are adjusted.

5. The operation control method according to claim 3, wherein: The determining of the reference value of the first active current state quantity and the reference value of the first reactive current state quantity at the second moment includes: Acquiring a setting value of a DC bus voltage of the power system and a setting value of reactive power of an AC power grid; Acquire an actual value of the DC bus voltage and an actual value of reactive power of the AC power grid at a second moment; Calculating a reference value of the first active current state quantity at the second moment based on the set value of the DC bus voltage and the actual value of the DC bus voltage at the second moment; Based on the set value of the reactive power of the AC power grid and the actual value of the reactive power of the AC power grid at the second moment, a reference value of the first reactive current state quantity at the second moment is calculated.

6. The operation control method according to claim 4, wherein: The determining of the reference value of the active power state quantity and the reference value of the reactive power state quantity at the second moment includes: Acquire an actual value of an active component and an actual value of a reactive component of the grid voltage at the second moment; Based on the reference value of the first active current state quantity at the second moment, the reference value of the first reactive current state quantity, the actual value of the active component of the grid voltage, and the actual value of the reactive component of the grid voltage, the reference value of the active power state quantity and the reference value of the reactive power state quantity at the second moment are determined.

7. The operation control method according to claim 4, wherein: The determining of the reference value of the active power state quantity and the reference value of the reactive power state quantity at the second moment includes: Acquire an actual value of the active component of the grid voltage, an actual value of the reactive component of the grid voltage, an actual value of the active component of the grid current, and an actual value of the reactive component of the grid current at the second moment; Based on the actual value of the active component of the grid voltage, the actual value of the reactive component of the grid voltage, the actual value of the active component of the grid current and the actual value of the reactive component of the grid current at the second moment, determine the reference value of the active power state quantity and the reference value of the reactive power state quantity at the second moment.

8. The operation control method according to claim 4, wherein: The determining of the feedback value of the active power state quantity and the feedback value of the reactive power state quantity at the second moment includes: Acquire an actual value of an active component and an actual value of a reactive component of the grid voltage at the second moment; Based on the reference value of the second active current state quantity at the second moment, the reference value of the second reactive current state quantity, the actual value of the active component of the grid voltage, and the actual value of the reactive component of the grid voltage, the feedback value of the active power state quantity and the feedback value of the reactive power state quantity at the second moment are calculated.

9. The operation control method according to any one of claims 2 to 8, wherein: Also includes: In the process of running the first control algorithm, obtaining an actual value of active power, an actual value of reactive power, an actual value of grid frequency, an actual value of grid voltage, an actual value of an active component of the grid voltage, an actual value of a reactive component of the grid voltage, an actual value of an active component of a grid current, and an actual value of a reactive component of the grid current of the power system at a third moment; Acquiring a setting value of the active power, a setting value of the reactive power, a setting value of the grid frequency, and a setting value of the grid voltage; Determine a reference value of a second active current state quantity and a reference value of a second reactive current state quantity at the third moment based on an actual value of the active power, an actual value of the reactive power, an actual value of the grid frequency, an actual value of the grid voltage, an actual value of the active component of the grid voltage, an actual value of the reactive component of the grid voltage, a set value of the active power, a set value of the reactive power, a set value of the grid frequency, and a set value of the grid voltage at the third moment; Determine the value of the active component and the value of the reactive component of the output potential of the converter at the third moment based on the reference value of the active current state quantity at the third moment, the reference value of the second reactive current state quantity, the actual value of the active component of the grid current, and the actual value of the reactive component of the grid current; The value of the active component and the value of the reactive component of the output potential of the converter at the third moment are used to adjust the grid frequency of the power system.

10. The operation control method according to claim 1, wherein: The first control algorithm is a virtual synchronous generator control algorithm, and the second control algorithm includes a constant DC voltage control algorithm and the virtual synchronous generator control algorithm; The obtaining of the actual value of the target electric parameter of the power system includes: Acquire an actual value of an active component of a grid current of the power system at a first moment; the first moment being a moment when the first working mode switching instruction is received; The step of setting the initial value of the target state variable to the actual value of the corresponding target electrical parameter comprises: An initial value of the first active current state quantity in the second control algorithm is set to the actual value of the active component of the grid current at the first moment.

11. The operation control method according to claim 10, wherein: After starting to run the second control algorithm, the method further includes: Determining a reference value of the first active current state quantity at a second moment; determining a reference value of a second reactive current state at the second moment; Acquire an actual value of an active component and an actual value of a reactive component of the grid current at the second moment; Based on the reference value of the first active current state quantity at the second moment, the reference value of the second reactive current state quantity, the actual value of the active component of the grid current, and the actual value of the reactive component of the grid current, the output of the converter at the second moment is determined. The value of the active component and the value of the reactive component of the potential; the value of the active component and the value of the reactive component of the output potential of the converter at the second moment are used to control the grid voltage of the power system.

12. The operation control method according to claim 11, wherein: The determining of the reference value of the first active current state quantity at the second moment includes: Obtaining a setting value of a DC bus voltage of the power system; Acquire the actual value of the DC bus voltage at the second moment; Based on the set value of the DC bus voltage and the actual value of the DC bus voltage at the second moment, a reference value of the first active current state quantity at the second moment is calculated.

13. The operation control method according to claim 11, wherein: The determining a reference value of the second reactive current state at the second moment includes: Determining a reference value of the active power state quantity at the second moment; Determining a feedback value of the active power state quantity at the second moment; Acquire an actual value of reactive power of the power system, an actual value of an active component of a grid voltage, and an actual value of a reactive component of the grid voltage at the second moment; Obtaining the setting value of the reactive power, the setting value of the grid voltage, and the setting value of the grid frequency; Based on the reference value of the active power state quantity at the second moment, the feedback value of the active power state quantity, the actual value of the reactive power, the actual value of the active component of the grid voltage, the actual value of the reactive component of the grid voltage, the set value of the reactive power, the set value of the grid voltage, the set value of the grid frequency and the rated value of the grid frequency, determine the reference value of the second active current state quantity and the reference value of the second reactive current state quantity at the second moment.

14. The operation control method according to claim 13, wherein: The determining of the reference value of the active power state quantity at the second moment includes: Based on the reference value of the first active current state quantity at the second moment, the reference value of the second reactive current state quantity, the actual value of the active component of the grid voltage and the actual value of the reactive component of the grid voltage, the reference value of the active power state quantity at the second moment is determined.

15. The operation control method according to claim 13, wherein: The determining of the reference value of the active power state quantity at the second moment includes: Acquire an actual value of an active component and an actual value of a reactive component of the grid current at the second moment; Based on the actual value of the active component of the grid voltage at the second moment, the actual value of the reactive component of the grid voltage, the actual value of the active component of the grid current and the actual value of the reactive component of the grid current, the reference value of the active power state quantity at the second moment is determined.

16. The operation control method according to claim 13, wherein: The determining the feedback value of the active power state quantity at the second moment includes: Based on the reference value of the second active current state quantity at the second moment, the reference value of the second reactive current state quantity, the actual value of the active component of the grid voltage and the actual value of the reactive component of the grid voltage, the feedback value of the active power state quantity at the second moment is determined.

17. The operation control method according to any one of claims 10 to 16, wherein: Also includes: In the process of running the first control algorithm, obtaining the actual value of the active power, the actual value of the reactive power, the actual value of the grid frequency, the actual value of the grid voltage, the actual value of the active component of the grid voltage, the actual value of the reactive component of the grid voltage, the actual value of the active component of the grid current, and the actual value of the reactive component of the grid current of the power system at the third moment; Acquiring a setting value of the active power, a setting value of the reactive power, a setting value of the grid frequency, and a setting value of the grid voltage; Determine a reference value of a second active current state quantity and a reference value of a second reactive current state quantity at the third moment based on an actual value of the active power, an actual value of the reactive power, an actual value of the grid frequency, an actual value of the grid voltage, an actual value of the active component of the grid voltage, an actual value of the reactive component of the grid voltage, a set value of the active power, a set value of the reactive power, a set value of the grid frequency, and a set value of the grid voltage at the third moment; Determine the value of the active component and the value of the reactive component of the output potential of the converter at the third moment based on the reference value of the active current state quantity at the third moment, the reference value of the second reactive current state quantity, the actual value of the active component of the grid current, and the actual value of the reactive component of the grid current; The value of the active component and the value of the reactive component of the output potential of the converter at the third moment are used to control the grid frequency of the power system.

18. An operation control device for a converter in a grid-connected system, comprising: an acquisition module, configured to acquire an actual value of a target electrical parameter of the power system if a first working mode switching instruction is received during the operation of the first control algorithm; The target electrical parameter corresponds to the target state variable in the second control algorithm; The setting module is used to stop running the first control algorithm, set the initial value of the target state variable to the actual value of the corresponding target electrical parameter, and start running the second control algorithm.

19. An operation control device for a converter in a grid-connected system, comprising a memory and a computer program stored in the memory and executable on a processor, wherein the processor implements the operation control method according to any one of claims 1 to 17 when executing the computer program.

20. A computer-readable storage medium storing a computer program, wherein: When the computer program is executed by a processor, the operation control method according to any one of claims 1 to 17 is implemented.

21. A converter, comprising a converter module and the operation control device of the converter in the grid-connected system according to claim 18.

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