Method and device for switching network following type control mode and network constructing type control mode of wind turbine generator

Abstract

The invention provides a switching method and device for a wind turbine generator network-following type control mode and a network-constructing type control mode, and relates to the technical field of wind turbine generators. A two-dimensional coordinate system with the wind speed change range as the abscissa and the short-circuit ratio change range as the ordinate is constructed; determining a first stable operation domain of the following grid type wind turbine generator, a second stable operation domain of the constructing grid type wind turbine generator and hysteresis switching boundary conditions according to actual stability conditions of different points of the following grid type wind turbine generator and the constructing grid type wind turbine generator in the two-dimensional coordinate system; switching between a network following type control mode and a network constructing type control mode is carried out based on the hysteresis switching boundary condition; wherein secondary compensation is carried out on the frequency and the voltage based on a consistency algorithm when switching between the network following type control mode and the network constructing type control mode is carried out. Therefore, the switching frequency of wind turbine generator network following / network construction control is reduced, the disturbance problem in the switching process can be better restrained, and stable operation of the system is guaranteed.

Description

Technical Field

[0001] The present application relates to the technical field of wind turbines, and in particular to a method and device for switching between a grid-following control mode and a grid-forming control mode for a wind turbine. Background Art

[0002] With the rapid development of renewable energy generation technologies, particularly the increasing proportion of renewable energy sources like wind and solar power, the declining proportion of traditional synchronous generators, the widespread use of power electronic equipment, and the application of long-distance transmission technologies, the grid strength of power systems has continued to decline. Furthermore, since renewable energy generation is significantly affected by climate and weather conditions, characterized by intermittency, volatility, and uncertainty, this also leads to fluctuations in system grid strength. Against this backdrop, control strategies for grid-connected converters for renewable energy generators have become a research focus. Existing research has shown that installing a certain number of grid-connected control units in renewable energy stations can effectively mitigate the instability issues associated with fully grid-connected renewable energy stations in weak grid environments, providing reliable support for their stable operation. Given the significant fluctuations in grid strength in current power systems, the stability of GFM (grid-connected) and GFL (grid-connected) control systems in different grid strength environments differs significantly.

[0003] Among them, studying a smooth switching control strategy to meet the seamless switching between wind turbine grid-connected and grid-following control is of great significance for improving the stability of new energy sites. Currently, research on GFL / GFM switchable units mainly focuses on off-grid / grid-connected mode switching control. However, in grid-connected mode, there is relatively little research on switching control between GFL and GFM control to expand the stability boundary of the power system. Current research has the following three main problems: 1) The research process mainly considers converter system modeling, while ignoring the impact of power-side generators on system stability; 2) Some switching strategies still experience overvoltage and overcurrent during the transient process of switching; 3) Some pre-synchronization algorithms have problems such as complex calculations and difficult applications. Summary of the Invention

[0004] In view of this, the purpose of the present application is to provide a method and device for switching between grid-following and grid-forming control modes of a wind turbine generator set, which can effectively suppress disturbance problems during the switching process.

[0005] The embodiment of the present application provides a method for switching between a grid-following control mode and a grid-forming control mode for a wind turbine generator system, comprising the following steps:

[0006] Constructing a two-dimensional coordinate system with the wind speed variation range as the horizontal coordinate and the short-circuit ratio variation range as the vertical coordinate, and determining the first stable operation domain of the grid-following wind turbine and the second stable operation domain of the grid-forming wind turbine based on the actual stability of the grid-following wind turbine and the grid-forming wind turbine at different points in the two-dimensional coordinate system;

[0007] The hysteresis switching boundary conditions are determined according to the first stable operating domain and the second stable operating domain, and switching between the grid-following type and the grid-forming type control modes is performed based on the hysteresis switching boundary conditions; wherein, when switching between the grid-following type and the grid-forming type control modes, the frequency and voltage are secondary compensated based on the consistency algorithm.

[0008] In some embodiments, based on the actual stability of the grid-following and grid-forming wind turbines at different points in the two-dimensional coordinate system, the first stable operating domain of the grid-following wind turbine is determined to be (C1∪C3), and the second stable operating domain of the grid-forming wind turbine is determined to be (C2∪C3); when the operating environment of the wind turbine is in the area (C1∪C3), the grid-following control mode is adopted, and when the operating environment of the wind turbine is in the area (C2∪C3), the grid-forming control mode is adopted.

[0009] In some embodiments, the hysteresis switching boundary condition is determined to be region C3 based on the first stable operating domain and the second stable operating domain; when the operating environment of the wind turbine generator set exceeds region C3, switching between the grid-following and grid-forming control modes is performed.

[0010] In some embodiments, in the grid-following control mode, the machine-side converter controls the power captured by the wind turbine, and the grid-side converter is used to maintain the DC bus voltage and achieve synchronization with the grid through a phase-locked loop.

[0011] In some embodiments, in the grid-forming control mode, the operating characteristics of the synchronous generator are simulated based on the voltage source characteristics to achieve synchronization with the grid.

[0012] In some embodiments, the frequency is quadratically compensated using the following formula:

[0013]

[0014] Among them, Δω i is the quadratic frequency compensation value based on the consistency algorithm in switching control, ω i is the actual frequency value after switching, ω j is the frequency in the control mode before switching, ω ref is the rated frequency, a ij Represents the switching coefficient of the two control modes, b i It is the reference signal for inverter control.

[0015] In some embodiments, the voltage is compensated twice using the following formula:

[0016]

[0017] Where Δui is the secondary voltage compensation value based on the consistency algorithm in switching control, u i is the actual voltage value after switching, u j is the voltage in the control mode before switching, u ref is the rated voltage, a ij Represents the switching coefficient of the two control modes, b i It is the reference signal for inverter control.

[0018] In some embodiments, a device for switching between a grid-following control mode and a grid-forming control mode of a wind turbine is further provided, the device comprising:

[0019] a determination module for constructing a two-dimensional coordinate system with a wind speed variation range as the horizontal coordinate and a short-circuit ratio variation range as the vertical coordinate, and determining a first stable operation domain of the grid-following wind turbine and a second stable operation domain of the grid-forming wind turbine based on actual stability conditions of the grid-following wind turbine and the grid-forming wind turbine at different points in the two-dimensional coordinate system;

[0020] A switching module is used to determine the hysteresis switching boundary conditions according to the first stable operating domain and the second stable operating domain, and switch between the grid-following type and the grid-forming type control mode based on the hysteresis switching boundary conditions; wherein, when switching between the grid-following type and the grid-forming type control mode, the frequency and voltage are compensated twice.

[0021] In some embodiments, an electronic device is also provided, including: a processor, a memory and a bus, the memory storing machine-readable instructions executable by the processor, and when the electronic device is running, the processor and the memory communicate through the bus, and when the machine-readable instructions are executed by the processor, the steps of the method for switching between the grid-following type and the grid-forming type control mode of a wind turbine are performed as described in any one of the above.

[0022] In some embodiments, a computer-readable storage medium is also provided, on which a computer program is stored. When the computer program is executed by a processor, the steps of the method for switching between the grid-following type and the grid-forming type control mode of a wind turbine group as described above are executed.

[0023] The present application describes a method and device for switching between grid-following and grid-forming control modes for a wind turbine. The method constructs a two-dimensional coordinate system with the wind speed variation range as the horizontal coordinate and the short-circuit ratio variation range as the vertical coordinate. The method also determines the first stable operating domain of the grid-following wind turbine and the second stable operating domain of the grid-forming wind turbine based on the actual stability of the grid-following and grid-forming wind turbines at different points in the two-dimensional coordinate system. The method also determines hysteresis switching boundary conditions based on the first and second stable operating domains, and switches between the grid-following and grid-forming control modes based on the hysteresis switching boundary conditions. When switching between the grid-following and grid-forming control modes, the frequency and voltage are quadratically compensated based on a consistency algorithm. This reduces the switching frequency of the wind turbine's grid-following / grid-forming control, and can better suppress disturbances during the switching process, ensuring stable system operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 A flow chart showing a method for switching between a wind turbine generator set grid-following control mode and a grid-forming control mode according to an embodiment of the present application is shown;

[0026] Figure 2 A schematic diagram showing the stability performance of GFL and GFM wind turbines when the grid strength changes according to an embodiment of the present application;

[0027] Figure 3 A schematic diagram showing the stability performance of GFL and GFM wind turbines when the wind speed changes according to an embodiment of the present application;

[0028] Figure 4 A schematic diagram showing a comparison between the traditional switching indicator of an embodiment of the present application and the switching indicator proposed in the present application is shown;

[0029] Figure 5 A schematic diagram of the structure of a device for switching between a grid-following type and a grid-forming type control mode of a wind turbine generator system according to an embodiment of the present application is shown;

[0030] Figure 6 A schematic structural diagram of an electronic device according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. It should be understood that the drawings in the present application only serve the purpose of illustration and description and are not used to limit the scope of protection of the present application. In addition, it should be understood that the schematic drawings are not drawn to scale. The flowcharts used in this application illustrate the operations implemented according to some embodiments of the present application. It should be understood that the operations of the flowcharts can be implemented out of sequence, and steps without logical context can be reversed or implemented simultaneously. In addition, those skilled in the art, under the guidance of the contents of this application, can add one or more other operations to the flowchart, or remove one or more operations from the flowchart.

[0032] In addition, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application generally described and shown in the drawings here can be arranged and designed in various configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present application.

[0033] It should be noted that the term "comprising" will be used in the embodiments of the present application to indicate the existence of the features declared thereafter, but does not exclude the addition of other features.

[0034] In view of the technical problems raised by the background technology, the present application provides a method, device, electronic equipment and storage medium for switching between grid-following and grid-forming control modes of a wind turbine generator set, which can effectively suppress disturbance problems during the switching process.

[0035] See the instructions attached Figure 1 The present application provides a method for switching between a grid-following control mode and a grid-forming control mode for a wind turbine generator system, comprising the following steps:

[0036] S1. Construct a two-dimensional coordinate system with the wind speed variation range as the abscissa and the short-circuit ratio variation range as the ordinate, and determine a first stable operating domain of the grid-following wind turbine and a second stable operating domain of the grid-forming wind turbine based on the actual stability of the grid-following wind turbine and the grid-forming wind turbine at different points in the two-dimensional coordinate system;

[0037] S2. Determine the hysteresis switching boundary conditions according to the first stable operating domain and the second stable operating domain, and switch between the grid-following type and the grid-forming type control modes based on the hysteresis switching boundary conditions; wherein, when switching between the grid-following type and the grid-forming type control modes, perform secondary compensation on the frequency and voltage based on the consistency algorithm.

[0038] In order to clearly understand the technical solution of the embodiment of the present invention, the application scenario can be illustrated first. In this application, in the GFL grid-following control mode, the machine-side converter controls the power captured by the wind turbine, the grid-side converter is used to maintain the DC bus voltage, and realizes the synchronization process with the grid through the phase-locked loop. In the GFM grid-forming control mode, the GFM control strategy based on the voltage source characteristics can independently construct the reference voltage and phase of the system. In the GFM control system, the grid-side converter simulates the operating characteristics of the synchronous generator, such as inertia and damping, through the GFM control strategy to realize the synchronization process with the grid. Among them, the mathematical model of the GFL converter is shown in formula (1); the mathematical model of the GFM wind turbine based on virtual synchronous generator control is shown in formula (2).

[0039]

[0040] Where, ω represents the grid frequency, rad / s; θ represents the grid phase, rad; P ref , P, Q ref , Q represents the reference value and actual value of the active power and reactive power output by the grid-following converter, W, Var; i d 、i q 、u d 、u q Represents the dq axis components of the grid-connected point current and voltage, A, V; i dref 、i qref 、u dref 、u qref k represents the reference value of the dq axis components of the current and voltage control in the converter current loop and voltage loop, A, V; p_PLL 、k i_PLL 、k p_i1 、k p_u1 、k p_u2 、k i_i1 、k i_u1 、k i_u2 Represents the PI controller coefficient.

[0041]

[0042] Where J and D represent the inertia coefficient and damping coefficient of VSG control; ω0 represents the rated frequency reference value; U ref Indicates the output voltage reference value of the GFM converter; m q Represents the reactive power control coefficient; k p_i3 、k p_u3 、k i_i4 、k i_u4 Represents the PI control coefficient.

[0043] In step S1, the present application defines a new switching index that takes into account the real-time wind speed and grid strength changes, so as to better evaluate the real-time operating status of the wind turbine and select the appropriate control mode. This is because, in the existing switching model, the system grid strength is usually used as the switching standard. In an environment with high grid strength, the following type of control is adopted, and in an environment with low grid strength, the grid-forming type of control is adopted. However, this switching index does not take into account the impact of actual wind speed on system stability. The present application further analyzes the stability of the system under the conditions of changes in grid strength and wind speed, and the results are shown in the appendix of the specification. Figure 2 and instructions attached Figure 3 As can be seen, the stability of the two types of units exhibits opposite characteristics when wind speed and grid strength change. That is, the grid-following type control unit has better stability in a strong grid environment and low wind speed environment, while the grid-forming type unit has better support capabilities in a weak grid environment and high wind speed environment.

[0044] See the instructions attached Figure 4 In the figure, the horizontal axis represents the wind speed variation range, and the vertical axis represents the SCR variation range. In the resulting two-dimensional (v, SCR) coordinate system, the stable operating domains of the two wind turbines, GFL and GFM, are derived based on their actual stability at different (v, SCR) points. Region (C1∪C3) represents the stable operating range for grid-following turbines. When the (v, SCR) of the turbine's operating environment falls within this region, GFL control is suitable for operation. Region (C2∪C3) represents the stable operating range for grid-forming turbines. When the (v, SCR) of the turbine's operating environment falls within this region, GFM control is suitable for operation. In region C3, due to the low wind speed and moderate system SCR, both control methods exhibit good stability. This characteristic can be used as a boundary condition for system hysteresis switching, thereby reducing the system's switching frequency.

[0045] In one embodiment, a wind farm is equipped with wind turbines capable of switching between grid-following (GFL) and grid-forming (GFM) operation. A two-dimensional (v, SCR) coordinate system has been established, and the ranges of various regions have been determined. The wind speed v is assumed to be in m / s, and the short-circuit ratio (SCR) is dimensionless. Based on actual operating data and analysis, the following regions have been determined: Region C1 is defined for wind speeds v < 6 m / s and SCR > 3; Region C2 is defined for wind speeds v > 9 m / s and SCR < 2; and Region C3 is defined for wind speeds 6 m / s ≤ v ≤ 9 m / s and 2 ≤ SCR ≤ 3.

[0046] The situation of switching from grid-following type (GFL) to grid-forming type (GFM): Initially, the wind turbine operates in area C1, with wind speed v = 5m / s and SCR = 3.5. At this time, the wind turbine adopts the GFL control mode to operate stably. As the weather changes, the wind speed gradually increases. When the wind speed reaches 8m / s, the SCR becomes 2.5, and the operation point enters area C3. Since it is still in the area where both control methods can operate stably, the wind turbine does not switch the control mode for the time being. When the wind speed continues to increase to 10m / s, the SCR drops to 1.8, and the operation point enters area C2. At this time, the wind turbine switches from the GFL control mode to the GFM control mode to adapt to the high wind speed and weak grid environment to ensure stable operation.

[0047] Switching from grid-forming (GFM) to grid-following (GFL) control: The wind turbine initially operates in region C2, with a wind speed of v = 11 m / s and an SCR of 1.5, using GFM control mode. The wind speed then gradually decreases. When it drops to 8 m / s, the SCR reaches 2.2, and the operation point enters region C3, where the wind turbine maintains GFM control mode. When the wind speed further decreases to 5 m / s, the SCR increases to 3.2, and the operation point enters region C1. The wind turbine switches to GFL control mode, leveraging the stability of the strong grid to achieve stable operation.

[0048] Hysteresis switching avoids frequent switching: During the operation of the wind turbine, the wind speed and SCR may fluctuate near the boundary of area C3. For example, when the wind speed is 7m / s and SCR = 2.8, the wind turbine operates in area C3 and adopts the GFL control mode. If the wind speed rises to 8m / s briefly, the SCR becomes 2.5, and it is still in area C3, the wind turbine will not switch to GFM mode. Only when the wind speed continues to rise, causing the operating point to exceed area C3 and enter area C2, will the switch be made. Similarly, if the wind speed drops from 7m / s to 6m / s, the SCR becomes 3. As long as it is still in area C3, the current control mode will be maintained, avoiding frequent switching due to small fluctuations in wind speed or SCR, and ensuring the stability of the system.

[0049] In step S2, when the system receives an instruction to switch between the GFM and GFL control modes, the internal voltage and current control loop switches the controller to the new mode by resetting the external integrator. Although this method can achieve fast response, it will also produce overvoltage and overcurrent disturbances. To address this problem, the present application further proposes a wind turbine grid / grid seamless switching smooth control strategy based on a consistency algorithm, which minimizes the disturbance during the switching process by performing secondary compensation on the frequency and voltage amplitude of the system. Specifically, for the grid control and grid-following control units, the droop control considering secondary voltage and frequency regulation can be implemented by formula (3):

[0050]

[0051] Where, ω i ,u i are the frequency and voltage reference values of the inverter inner loop, ω0,u0 are the frequency and voltage balance points, n i ,m i Represents the droop control active coefficient and reactive coefficient, P i ,P ref i , Q i ,Q ref i Indicates the actual value and reference value of active power and reactive power, u i_ω ,u i_u are the secondary frequency and voltage regulation components of the converter, i represents the control mode, where i=1 is grid-forming control and i=2 is grid-following control.

[0052] Taking the consistency algorithm of frequency quadratic compensation as an example, suppose:

[0053] ω droop_i =ω0-n i (P i -P i ref ) (4)

[0054] For the droop control loop, when the system reaches a steady state, the converter droop coefficient is inversely proportional to the power deviation, that is:

[0055] n i (P i -P i ref )=Const (5)

[0056] That is, in different control modes, the converter ω droop_i When performing frequency compensation, the secondary frequency modulation component of the converter should be the difference between the GFL and GFM control output frequencies, that is:

[0057] Δω i =u i_ω (6)

[0058] At the same time, since the output frequency and voltage of the inverter under the two control modes operate on the same power grid, the shift of the two control droop curves should be consistent. Therefore, the consistency algorithm based on frequency quadratic compensation is designed as follows:

[0059]

[0060] Among them, Δω i is the quadratic frequency compensation value based on the consistency algorithm in switching control, ω i is the actual frequency value after switching, ωj is the frequency in the control mode before switching, ω ref is the rated frequency, a ij Represents the switching coefficient of the two control modes, b i It is the reference signal for inverter control.

[0061] Similarly, the consistency algorithm based on voltage quadratic compensation can be designed as follows:

[0062]

[0063] Where Δu i is the secondary voltage compensation value based on the consistency algorithm in switching control, u i is the actual voltage value after switching, u j is the voltage in the control mode before switching, u ref is the rated voltage, a ij Represents the switching coefficient of the two control modes, b i It is the reference signal for inverter control.

[0064] This application provides a method for switching between grid-following and grid-forming control modes for wind turbines. First, a grid-following / grid-forming switching indicator is proposed. Compared with traditional switching indicators, the proposed switching indicator can better evaluate the real-time operating status of the wind turbine and, under certain circumstances, reduce the switching frequency of the wind turbine's grid-following / grid-forming control. Subsequently, a smooth switching control strategy is proposed based on a consistency algorithm. Compared with existing control strategies, this strategy can better suppress disturbances during the switching process and ensure stable system operation. At the same time, compared with other control strategies, this strategy has a simpler calculation method and is easier to implement.

[0065] Based on the same inventive concept, an embodiment of the present application also provides a switching device for the grid-following and grid-forming control modes of a wind turbine. Since the principle of solving the problem by the device in the embodiment of the present application is similar to the above-mentioned method for switching the grid-following and grid-forming control modes of a wind turbine in the embodiment of the present application, the implementation of the device can refer to the implementation of the method, and the repeated parts will not be repeated.

[0066] As the instruction manual Figure 5 As shown, the embodiment of the present application further provides a device for switching between a grid-following type and a grid-forming type control mode of a wind turbine generator set, the device comprising:

[0067] Determination module 501 is used to construct a two-dimensional coordinate system with the wind speed variation range as the abscissa and the short-circuit ratio variation range as the ordinate, and determine a first stable operating domain of the grid-following wind turbine and a second stable operating domain of the grid-forming wind turbine based on the actual stability of the grid-following wind turbine and the grid-forming wind turbine at different points in the two-dimensional coordinate system;

[0068] The switching module 502 is used to determine the hysteresis switching boundary conditions according to the first stable operating domain and the second stable operating domain, and to switch between the grid-following type and the grid-forming type control modes based on the hysteresis switching boundary conditions; wherein, when switching between the grid-following type and the grid-forming type control modes, the frequency and voltage are compensated secondary.

[0069] In one embodiment, the determination module 501 determines that the first stable operating domain of the grid-following wind turbine is (C1∪C3) and the second stable operating domain of the grid-forming wind turbine is (C2∪C3) according to the actual stability of the grid-following wind turbine and the grid-forming wind turbine at different points in the two-dimensional coordinate system; when the operating environment of the wind turbine is in the area (C1∪C3), the grid-following control mode is adopted, and when the operating environment of the wind turbine is in the area (C2∪C3), the grid-forming control mode is adopted.

[0070] In one embodiment, the switching module 502 determines that the hysteresis switching boundary condition is region C3 based on the first stable operation domain and the second stable operation domain; when the operating environment of the wind turbine generator system exceeds region C3, the switching between the grid-following type and the grid-forming type control mode is performed.

[0071] In one embodiment, in the grid-following control mode, the generator-side converter controls the power captured by the wind turbine, while the grid-side converter maintains the DC bus voltage and achieves synchronization with the grid via a phase-locked loop. In the grid-forming control mode, the operating characteristics of the synchronous generator are simulated based on the voltage source characteristics to achieve synchronization with the grid.

[0072] In one embodiment, the switching module 502 performs secondary compensation on the frequency using the following formula:

[0073]

[0074] Among them, Δω i is the quadratic frequency compensation value based on the consistency algorithm in switching control, ω i is the actual frequency value after switching, ω j is the frequency in the control mode before switching, ω ref is the rated frequency, a ij Represents the switching coefficient of the two control modes, b i It is the reference signal for inverter control.

[0075] In one embodiment, the switching module 502 performs secondary compensation on the voltage using the following formula:

[0076]

[0077] Where Δu iis the secondary voltage compensation value based on the consistency algorithm in switching control, u i is the actual voltage value after switching, u j is the voltage in the control mode before switching, u ref is the rated voltage, a ij Represents the switching coefficient of the two control modes, b i It is the reference signal for inverter control.

[0078] The real-time structured light reconstruction device based on normalized extended polar geometry described in this application constructs a two-dimensional coordinate system with a wind speed variation range as the horizontal coordinate and a short-circuit ratio variation range as the vertical coordinate through a determination module, and determines a first stable operating domain of the grid-following wind turbine and a second stable operating domain of the grid-forming wind turbine based on the actual stability of the grid-following and grid-forming wind turbines at different points in the two-dimensional coordinate system; determines a hysteresis switching boundary condition based on the first and second stable operating domains through a switching module, and switches between the grid-following and grid-forming control modes based on the hysteresis switching boundary condition; wherein, when switching between the grid-following and grid-forming control modes, quadratic compensation of frequency and voltage is performed based on a consistency algorithm. This reduces the switching frequency of the wind turbine grid-following / grid-forming control, and can better suppress disturbance problems during the switching process, ensuring stable operation of the system.

[0079] Based on the same concept of the present invention, as shown in the attached specification Figure 6 As shown, an embodiment of the present application provides a structure of an electronic device 600, which includes: at least one processor 601, at least one network interface 604 or other user interface 603, a memory 605, and at least one communication bus 602. The communication bus 602 is used to realize the connection and communication between these components. The electronic device 600 optionally includes a user interface 603, including a display (for example, a touch screen, LCD, CRT, holographic imaging (Holographic) or projection (Projector), etc.), a keyboard or a pointing device (for example, a mouse, trackball (trackball), touchpad or touch screen, etc.).

[0080] The memory 605 may include a read-only memory and a random access memory, and provides instructions and data to the processor 601. A portion of the memory 605 may also include a non-volatile random access memory (NVRAM).

[0081] In some embodiments, the memory 605 stores the following elements, executable modules, or data structures, or a subset or extended set thereof:

[0082] Operating system 6051, including various system programs used to implement various basic services and handle hardware-based tasks;

[0083] The application module 6052 includes various application programs, such as a launcher, a media player, a browser, etc., which are used to implement various application services.

[0084] In the embodiment of the present application, by calling the program or instruction stored in the memory 605, the processor 601 is used to execute the steps of a method for switching between a grid-following type and a grid-forming type control mode of a wind turbine.

[0085] The present application also provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the computer program executes steps in a method for switching between a grid-following control mode and a grid-forming control mode of a wind turbine generator set.

[0086] Specifically, the storage medium can be a general storage medium, such as a mobile disk, hard disk, etc. When the computer program on the storage medium is run, it can execute the above-mentioned method for switching between the grid-following type and the grid-forming type control mode of the wind turbine, and can effectively suppress the disturbance problem of the switching process.

[0087] In the embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interface, the indirect coupling or communication connection of the device or unit can be electrical, mechanical or other forms.

[0088] Units described as separate components may or may not be physically separate, and components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0089] In addition, each functional unit in the embodiments provided in the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0090] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the various embodiments of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0091] Finally, it should be noted that the above embodiments are only specific implementation methods of the present application, which are used to illustrate the technical solutions of the present application, rather than to limit them. The scope of protection of the present application is not limited thereto. Although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that any person skilled in the art can modify or easily conceive of changes to the technical solutions described in the above embodiments within the technical scope disclosed in the present application, or replace some of the technical features therein with equivalents. However, these modifications, changes, or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application. They should all be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A method for switching between a wind turbine generator set's grid-following and grid-forming control modes, characterized in that: The method comprises the following steps: Constructing a two-dimensional coordinate system with the wind speed variation range as the horizontal coordinate and the short-circuit ratio variation range as the vertical coordinate, and determining the first stable operation domain of the grid-following wind turbine and the second stable operation domain of the grid-forming wind turbine based on the actual stability of the grid-following wind turbine and the grid-forming wind turbine at different points in the two-dimensional coordinate system; The hysteresis switching boundary conditions are determined according to the first stable operating domain and the second stable operating domain, and switching between the grid-following type and the grid-forming type control modes is performed based on the hysteresis switching boundary conditions; wherein, when switching between the grid-following type and the grid-forming type control modes, the frequency and voltage are secondary compensated based on the consistency algorithm.

2. A method for switching between a grid-following control mode and a grid-forming control mode for a wind turbine according to claim 1, characterized in that: in, According to the actual stability of the grid-following and grid-forming wind turbines at different points in the two-dimensional coordinate system, the first stable operating domain of the grid-following wind turbine is determined to be (C1∪C3), and the second stable operating domain of the grid-forming wind turbine is determined to be (C2∪C3); when the operating environment of the wind turbine is in the area (C1∪C3), the grid-following control mode is adopted, and when the operating environment of the wind turbine is in the area (C2∪C3), the grid-forming control mode is adopted.

3. A method for switching between a grid-following control mode and a grid-building control mode for a wind turbine according to claim 2, characterized in that: in, Based on the first stable operation domain and the second stable operation domain, the hysteresis switching boundary condition is determined to be area C3; when the operating environment of the wind turbine generator system exceeds area C3, switching between the grid-following type and the grid-forming type control mode is performed.

4. A method for switching between a grid-following control mode and a grid-building control mode for a wind turbine according to claim 3, characterized in that: in, In the grid-following control mode, the machine-side converter controls the power captured by the wind turbine, and the grid-side converter is used to maintain the DC bus voltage and achieve synchronization with the grid through a phase-locked loop.

5. A method for switching between a grid-following control mode and a grid-building control mode for a wind turbine according to claim 3, characterized in that: in, In the grid-forming control mode, the operating characteristics of the synchronous generator are simulated based on the voltage source characteristics to achieve synchronization with the power grid.

6. A method for switching between a grid-following control mode and a grid-building control mode for a wind turbine according to claim 1, characterized in that: The frequency is compensated twice using the following formula: Among them, Δω i is the quadratic frequency compensation value based on the consistency algorithm in switching control, ω i is the actual frequency value after switching, ω j is the frequency in the control mode before switching, ω ref is the rated frequency, a ij Represents the switching coefficient of the two control modes, b i It is the reference signal for inverter control.

7. A method for switching between a grid-following control mode and a grid-building control mode for a wind turbine according to claim 6, characterized in that: The voltage is compensated twice using the following formula: Where Δu i is the secondary voltage compensation value based on the consistency algorithm in switching control, u i is the actual voltage value after switching, u j is the voltage in the control mode before switching, u ref is the rated voltage, a ij Represents the switching coefficient of the two control modes, b i It is the reference signal for inverter control.

8. A device for switching between grid-following and grid-building control modes for a wind turbine generator set, characterized in that: The device comprises: a determination module for constructing a two-dimensional coordinate system with a wind speed variation range as the horizontal coordinate and a short-circuit ratio variation range as the vertical coordinate, and determining a first stable operation domain of the grid-following wind turbine and a second stable operation domain of the grid-forming wind turbine based on actual stability conditions of the grid-following wind turbine and the grid-forming wind turbine at different points in the two-dimensional coordinate system; A switching module is used to determine the hysteresis switching boundary conditions according to the first stable operating domain and the second stable operating domain, and switch between the grid-following type and the grid-forming type control mode based on the hysteresis switching boundary conditions; wherein, when switching between the grid-following type and the grid-forming type control mode, the frequency and voltage are compensated twice.

9. An electronic device, characterized in that: include: A processor, a memory and a bus, wherein the memory stores machine-readable instructions executable by the processor. When the electronic device is running, the processor and the memory communicate via the bus. When the machine-readable instructions are executed by the processor, the steps of the method for switching between the grid-following type and the grid-forming type control mode of a wind turbine set as described in any one of claims 1 to 7 are performed.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, which, when executed by a processor, executes the steps of a method for switching between a grid-following control mode and a grid-forming control mode of a wind turbine as claimed in any one of claims 1 to 7.

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