Power outer loop dynamic control fault ride-through method and system for network-forming converter

Abstract

The invention relates to the technical field of network construction type converter control, in particular to a network construction type converter power outer loop dynamic control fault ride-through method and system, and the method comprises the steps: constructing a VSG active-frequency control loop and a VSG reactive-voltage control loop; constructing a VSG control-based network construction type converter control loop on the basis of the control loop; during a fault period, the VSG is converted from an active control priority mode to a reactive control priority mode, the VSG dynamically adjusts an active power instruction value and a reactive power instruction value, the active power of the network-forming converter is reduced, and the reactive power is increased; and dynamically adjusting the active droop coefficient according to the voltage drop degree of the power grid, and recovering the power system after the fault is removed. According to the method, the short-term stability of the system is maintained by reducing the active power instruction value during the fault period, and meanwhile, the active droop coefficient is dynamically adjusted, so that the transient recovery process of the VSG after the fault is removed is optimized, and the fault ride-through capability and the transient stability are improved.

Description

Technical Field

[0001] This invention relates to the field of grid-type converter control technology, and in particular to a method and system for fault ride-through of dynamic control of the outer power loop of a grid-type converter. Background Technology

[0002] my country's energy structure is rapidly transitioning towards renewable energy, building a new power system dominated by new energy sources. Against this backdrop, various types of new energy power generation units are achieving efficient grid connection, reliable transmission, and flexible consumption through power electronic equipment. Power electronic equipment has become one of the core components of modern power systems. However, large-scale wind and solar power generation, connected to the grid through power electronic equipment, is gradually replacing traditional synchronous generators.

[0003] Grid-type converters are more suitable for power grids with low system strength, low physical inertia, and poor stability. Under short-circuit fault conditions, the rapid increase in short-circuit current poses a serious threat to the transient stability of the power grid. Unlike synchronous generators, grid-type converters do not have an actual physical mechanical rotor and are limited by the overcurrent capacity of the semiconductor devices themselves. Therefore, they cannot utilize the fault response strategies of synchronous generators and face the risk of overcurrent protection triggering grid disconnection. Thus, during fault periods, grid-type converters must employ certain fault ride-through control methods to ensure continued stable operation when the power grid encounters large disturbances.

[0004] Existing fault ride-through methods for grid-connected converters mostly suppress VSG (Virtual Synchronous Generator) fault currents by dynamically limiting virtual impedance, thus protecting converter devices from fault current surges. During fault ride-through, maintaining the active support characteristics of the VSG also requires maintaining transient stability of the power angle and voltage support. To improve the transient stability of the VSG after a fault occurs, this can be achieved by reducing the active power command value or increasing the active power droop factor. However, some existing studies on VSG power command control strategies only consider changes in the power command value, neglecting the dynamic performance of the VSG's transient recovery process after fault clearance. While this single control method can maintain short-term system stability during a fault by reducing the active power command value, after fault clearance, the lack of dynamic adjustment of the active power droop factor often leads to oscillations or delays in the VSG's power recovery process, resulting in poor system dynamic performance.

[0005] The information disclosed in this background section is intended only to enhance the understanding of the general background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0006] This invention provides a method and system for dynamic control of the power outer loop of a grid-type converter to overcome faults, thereby effectively solving the problems in the background art.

[0007] To achieve the above objectives, the technical solution adopted by this invention is: a fault ride-through method for dynamic control of the outer power loop of a grid-type converter, comprising the following steps:

[0008] Construct a VSG active-frequency control loop and a VSG reactive-voltage control loop;

[0009] Based on the above control loop, a VSG-based grid converter control loop is constructed;

[0010] During a power system fault, the VSG switches from active power control priority mode to reactive power control priority mode. The VSG dynamically adjusts the active power command value and reactive power command value, reducing the active power of the grid-type converter and increasing the reactive power.

[0011] The active power droop coefficient is dynamically adjusted according to the degree of voltage drop in the power grid, so as to restore the power system after the fault is cleared.

[0012] Furthermore, the VSG active-frequency control loop includes:

[0013] ;

[0014] In the formula, For frequency, This is a frequency reference value. This is the actual value of active power. This is the active power command value. Let be the moment of inertia, and s be the complex variable of the Laplace transform; This is the active power droop coefficient. is the damping coefficient.

[0015] Furthermore, the VSG reactive-voltage control loop includes:

[0016] ;

[0017] In the formula, The integral coefficient of the reactive power-voltage control loop; This is a reference value for the converter voltage amplitude; This provides the virtual reactive power output for the converter. Q is the no-load electromotive force of the converter, and Q is the actual value of reactive power. ref This is a reference value for reactive power; n q This is the reactive power droop factor. This is the rated voltage of the grid-connected converter.

[0018] Furthermore, the VSG dynamically adjusts the active power command value and reactive power command value, including:

[0019] ;

[0020] ;

[0021] In the formula, This is the active power command value. This is the reactive power command value; Q is the active power command value. ref This is a reference value for reactive power; V d The active voltage, V q This is reactive voltage; , These are the dynamic reactive current coefficients under different magnitudes of grid voltage drops; This is the reactive current component. The rated output current of the grid-type converter, For grid-side current of grid-type converter The q-axis component, V gp This is the per-unit value of the grid-connected voltage.

[0022] Furthermore, the dynamic adjustment of the active power droop coefficient based on the degree of grid voltage drop includes:

[0023] ;

[0024] In the formula, This is the active power droop coefficient. This is the initial value of the active power droop coefficient; To adjust the gain for active droop coefficient, V gp This is the grid voltage.

[0025] The present invention also includes a fault ride-through system for dynamic control of the outer power loop of a grid-type converter, using the method described above, wherein the system comprises:

[0026] The VSG control unit is used to construct the VSG active-frequency control loop and the VSG reactive-voltage control loop;

[0027] The converter control unit is used to construct a VSG-based grid converter control loop based on the above control loop;

[0028] The power command unit is used to switch the VSG from active power control priority mode to reactive power control priority mode during power system faults. The VSG dynamically adjusts the active power command value and reactive power command value to reduce the active power of the grid-type converter and increase the reactive power.

[0029] The droop system adjustment unit is used to dynamically adjust the active power droop coefficient according to the degree of grid voltage drop, so as to realize the power system recovery after the fault is cleared.

[0030] The present invention also includes a computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the computer program, implements the method as described above.

[0031] The present invention also includes a storage medium having a computer program stored thereon, which, when executed by a processor, implements the method as described above.

[0032] The beneficial effects of this invention are as follows: By constructing a grid-type converter control loop based on VSG control, during a power system fault, the VSG switches from an active power control priority mode to a reactive power control priority mode. The VSG dynamically adjusts the active power command value and the reactive power command value, reducing the active power of the grid-type converter and increasing the reactive power. During a fault, the short-term stability of the system is maintained by reducing the active power command value, while the active power droop coefficient is dynamically adjusted to optimize the transient recovery process of the VSG after the fault is cleared, thereby improving the fault ride-through capability and transient stability of the VSG. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a flowchart of the method in Example 1;

[0035] Figure 2 This is a schematic diagram of the system structure in Example 2;

[0036] Figure 3 This is a block diagram of the VSG active-frequency control loop in Example 2;

[0037] Figure 4 This is a block diagram of the VSG reactive-voltage control loop in Example 2;

[0038] Figure 5 This is a block diagram of the grid-type converter control based on VSG control in Example 2;

[0039] Figure 6 This is a block diagram of the VSG outer loop control based on the coordination of power command value and active power droop coefficient in Example 2;

[0040] Figure 7 This is a schematic diagram of the structure of the computer device of the present invention. Detailed Implementation

[0041] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0042] Example 1:

[0043] like Figure 1 As shown: A fault ride-through method for dynamic control of the power outer loop of a grid-type converter includes the following steps:

[0044] Construct a VSG active-frequency control loop and a VSG reactive-voltage control loop;

[0045] Based on the above control loop, a VSG-based grid converter control loop is constructed;

[0046] During a power system fault, the VSG switches from active power control priority mode to reactive power control priority mode. The VSG dynamically adjusts the active power command value and reactive power command value, reducing the active power of the grid-type converter and increasing the reactive power.

[0047] The active power droop coefficient is dynamically adjusted according to the degree of voltage drop in the power grid, so as to achieve rapid power system recovery after fault clearance.

[0048] By constructing a grid-type converter control loop based on VSG control, during power system faults, the VSG switches from active power control priority mode to reactive power control priority mode. The VSG dynamically adjusts the active power command value and reactive power command value, reducing the active power of the grid-type converter and increasing the reactive power. During faults, the system maintains short-term stability by reducing the active power command value, while dynamically adjusting the active power droop coefficient to optimize the transient recovery process of the VSG after fault clearance, thereby improving the fault ride-through capability and transient stability of the VSG.

[0049] In this embodiment, the VSG active-frequency control loop includes:

[0050] ;

[0051] In the formula, For frequency, This is a frequency reference value. This is the actual value of active power. This is the active power command value. Let be the moment of inertia, and s be the complex variable of the Laplace transform; This is the active power droop coefficient. is the damping coefficient.

[0052] The VSG reactive-voltage control loop includes:

[0053] ;

[0054] In the formula, The integral coefficient of the reactive power-voltage control loop; This is a reference value for the converter voltage amplitude; This provides the virtual reactive power output for the converter. Q is the no-load electromotive force of the converter, and Q is the actual value of reactive power. ref This is a reference value for reactive power; n q This is the reactive power droop factor. This is the rated voltage of the grid-connected converter.

[0055] The VSG dynamically adjusts the active power command value and reactive power command value, including:

[0056] ;

[0057] ;

[0058] In the formula, This is the active power command value. This is the reactive power command value; Q is the active power command value. ref This is a reference value for reactive power; V d The active voltage, V q This is reactive voltage; , These are the dynamic reactive current coefficients under different magnitudes of grid voltage drops; This is the reactive current component. The rated output current of the grid-type converter, For grid-side current of grid-type converter The q-axis component, V gp This is the per-unit value of the grid-connected voltage.

[0059] Dynamically adjust the active power droop factor according to the degree of grid voltage drop, including:

[0060] ;

[0061] In the formula, This is the active power droop coefficient. This is the initial value of the active power droop coefficient; To adjust the gain for active droop coefficient, V gp This is the per-unit value of the grid-connected voltage.

[0062] like Figure 2 As shown, this embodiment also includes a grid-type converter power outer loop dynamic control fault ride-through system, using the method described above. The system includes:

[0063] The VSG control unit is used to construct the VSG active-frequency control loop and the VSG reactive-voltage control loop;

[0064] The converter control unit is used to construct a VSG-based grid converter control loop based on the above control loop;

[0065] The power command unit is used to switch the VSG from active power control priority mode to reactive power control priority mode during power system faults. The VSG dynamically adjusts the active power command value and reactive power command value to reduce the active power of the grid-type converter and increase the reactive power.

[0066] The droop system adjustment unit is used to dynamically adjust the active power droop coefficient according to the degree of grid voltage drop, so as to realize the rapid recovery of the power system after the fault is cleared.

[0067] Example 2:

[0068] This embodiment includes a fault ride-through method for dynamic control of the outer power loop of a grid-type converter. During a fault, the method reduces the active power command value to maintain the short-term stability of the system, while dynamically adjusting the active power droop coefficient to optimize the transient recovery process of the VSG after the fault is cleared.

[0069] According to the active power-frequency droop characteristic, the droop characteristic equation between the active power and frequency of the synchronous generator governor is:

[0070] (1)

[0071] Actual value of active power output of GFM converter based on VSG control With instruction value The relational expression is obtained by performing a Laplace transform:

[0072] (2)

[0073] To incorporate virtual inertia and damping into the converter control loop, substitute equation (1) into equation (2), and let... ,get:

[0074] (3)

[0075] Therefore, the active-frequency regulation equation for the GFM converter based on VSG control is obtained as follows:

[0076] (4)

[0077] As shown in equation (4), the VSG active-frequency control loop borrows the droop control characteristics of a synchronous generator. Its core idea is to detect the deviation between the actual active power value and the active power reference value in real time, and adjust the output electromagnetic torque accordingly to achieve frequency control of the system. In the equation, the moment of inertia... The introduction of this technology gives VSG a "virtual inertia" characteristic, with a damping coefficient... This setting provides the system with effective oscillation suppression capabilities, enabling the converter to not only adjust output power but also stabilize frequency changes during grid fluctuations. Finally, to obtain the phase reference value of the converter output voltage... , need to Perform integration processing.

[0078] Based on the above analysis, the VSG active-frequency control loop block diagram is as follows: Figure 3 As shown.

[0079] Based on the reactive power-voltage droop characteristic, the droop characteristic equation between reactive power and voltage of a synchronous generator governor can be expressed in the following form:

[0080] (5)

[0081] In the formula, This provides the virtual reactive power output for the converter. This is the no-load potential of the converter.

[0082] The reactive power-voltage droop control system monitors the changes in reactive power of the load in real time and automatically adjusts the amplitude of the output voltage according to the fluctuations in load demand. Equation (5) is an open-loop control. To enable the GFM converter based on VSG control to achieve stable AC voltage control in grid-connected mode, an integral controller is introduced to improve voltage control performance, namely:

[0083] (6)

[0084] In the formula, The integral coefficient of the reactive power-voltage control loop; This is a reference value for the voltage amplitude of the converter.

[0085] Substituting equation (5) into equation (6), we obtain the mathematical model of the VSG reactive-voltage control loop as follows:

[0086] (7)

[0087] Based on the above analysis, the block diagram of the reactive power-voltage control loop of the GFM converter based on VSG control is as follows: Figure 4 As shown.

[0088] Combined formula (4), formula (7) Figure 3 and Figure 4 The control block diagram of the GFM converter based on VSG control is as follows: Figure 5 As shown.

[0089] During fault ride-through, the converter must maintain continuous operation within a certain voltage range without disconnecting from the grid. Therefore, the converter needs to inject reactive current into the grid connection point to achieve active voltage support. The degree of grid voltage sag is related to the reactive current injected by the converter. The relationship expression between them is:

[0090] (8)

[0091] In the formula, The dynamic reactive current coefficient is used when the grid voltage drops below 0.2 pu, and is generally taken as 1.05.

[0092] Equation (8) can be used to obtain the relationship between the grid voltage drop and the active current component of VSG. The relationship expression between them is:

[0093] (9)

[0094] As can be seen from equations (8) and (9), during fault ride-through, the VSG should switch from active power control priority mode to reactive power control priority mode to support the grid voltage. The reactive current injected by the converter is higher than the reactive current during normal operation, while the active current decreases accordingly. The magnitude of the reactive current is adjusted according to the degree of grid voltage drop, thereby achieving grid voltage support and improving the fault ride-through capability of the VSG.

[0095] Active power output from VSG to the grid during fault ride-through and reactive power for:

[0096] (10)

[0097] Substituting equations (8) and (9) into equation (10), we obtain the VSG active power command value during fault ride-through. and reactive power command value for:

[0098] (11)

[0099] (12)

[0100] During a fault, as the grid voltage drops, the VSG dynamically adjusts the active and reactive power command values ​​based on equations (11) and (12). When the grid voltage... hour, and These are the corresponding initial instruction values. and When the grid voltage drops between 0.2 and 0.9 pu, This will be reduced to maintain the stability of the system's power angle. This will increase the reactive current injected into the system. When the grid voltage back, This will be further reduced to increase the deceleration area and decrease the acceleration area, thereby improving the system's stability margin. It will be further increased to maintain a certain voltage support.

[0101] Active sagging coefficient Dynamic adjustments are made based on the degree of grid voltage sag to optimize the dynamic recovery process after fault clearance. Active power droop factor. The dynamic adjustment formula is:

[0102] (13)

[0103] In the formula, This is the initial value of the active power droop coefficient; The gain is adjusted by the active droop coefficient.

[0104] By employing a dynamic power compensation control strategy, the active power command value is corrected, thereby reducing the power angle offset. :

[0105] (14)

[0106] In the formula, For line reactance, This refers to the grid voltage after the fault occurred. This refers to the VSG terminal voltage after the fault occurred. This represents the active power command value of the VSG during fault ride-through.

[0107] Based on the above analysis, the VSG outer loop control block diagram based on the coordination of power command value and active power droop coefficient is obtained as follows: Figure 6 As shown.

[0108] This embodiment proposes a fault ride-through method for the dynamic control of the outer power loop of a grid-type converter based on the coordinated control of the power command value and the active power droop coefficient. During a fault, the short-term stability of the system is maintained by reducing the active power command value, while the active power droop coefficient is dynamically adjusted to optimize the transient recovery process of the VSG after the fault is cleared, thereby improving the fault ride-through capability and transient stability of the VSG.

[0109] Please see Figure 7The diagram shows a structural schematic of a computer device provided in an embodiment of this application. An embodiment of this application provides a computer device 400, including a processor 410 and a memory 420. The memory 420 stores a computer program executable by the processor 410. When the computer program is executed by the processor 410, it performs the method described above.

[0110] This application embodiment also provides a storage medium 430, on which a computer program is stored, and the computer program is executed by a processor 410 to perform the above method.

[0111] The storage medium 430 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read Only Memory (EPROM), Programmable Red-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk.

[0112] In the description of this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. "A plurality of" means two or more, unless otherwise explicitly specified.

[0113] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0114] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0115] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing a particular logical function or process, and the scope of the preferred embodiments of the invention includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as will be understood by those skilled in the art to which embodiments of the invention pertain.

[0116] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0117] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0118] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0119] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A fault ride-through method for dynamic control of the power outer loop of a grid-type converter, characterized in that, Includes the following steps: Construct a VSG active-frequency control loop and a VSG reactive-voltage control loop; Based on the above control loop, a VSG-based grid converter control loop is constructed; During a power system fault, the VSG switches from active power control priority mode to reactive power control priority mode. The VSG dynamically adjusts the active power command value and reactive power command value, reducing the active power of the grid-type converter and increasing the reactive power. The active power droop coefficient is dynamically adjusted according to the degree of voltage drop in the power grid, so as to restore the power system after the fault is cleared.

2. The fault ride-through method for dynamic control of the outer power loop of a grid-type converter according to claim 1, characterized in that, The VSG active-frequency control loop includes: ； In the formula, For frequency, This is a frequency reference value. This is the actual value of active power. This is the active power command value. Let be the moment of inertia, and s be the complex variable of the Laplace transform; This is the active power droop coefficient. is the damping coefficient.

3. The fault ride-through method for dynamic control of the outer power loop of a grid-type converter according to claim 2, characterized in that, The VSG reactive-voltage control loop includes: ； In the formula, The integral coefficient of the reactive power-voltage control loop; This is a reference value for the converter voltage amplitude; This provides the virtual reactive power output for the converter. Q is the no-load electromotive force of the converter, and Q is the actual value of reactive power. ref This is a reference value for reactive power; n q This is the reactive power droop factor. This is the rated voltage of the grid-connected converter.

4. The fault ride-through method for dynamic control of the outer power loop of a grid-type converter according to claim 1, characterized in that, The VSG dynamically adjusts the active power command value and reactive power command value, including: ； ； In the formula, This is the active power command value. This is the reactive power command value; Q is the active power command value. ref This is a reference value for reactive power; V d The active voltage, V q This is reactive voltage; , These are the dynamic reactive current coefficients under different magnitudes of grid voltage drops; This is the reactive current component. The rated output current of the grid-type converter, For grid-side current of grid-type converter The q-axis component, V gp This is the per-unit value of the grid-connected voltage.

5. The fault ride-through method for dynamic control of the outer power loop of a grid-type converter according to claim 1, characterized in that, The dynamic adjustment of the active power droop coefficient based on the degree of grid voltage drop includes: ； In the formula, This is the active power droop coefficient. This is the initial value of the active power droop coefficient; To adjust the gain for active droop coefficient, V gp This is the per-unit value of the grid-connected voltage.

6. A fault ride-through system for dynamic control of the outer power loop of a grid-type converter, characterized in that, Using the method as described in any one of claims 1 to 5, the system comprises: The VSG control unit is used to construct the VSG active-frequency control loop and the VSG reactive-voltage control loop; The converter control unit is used to construct a VSG-based grid converter control loop based on the above control loop; The power command unit is used to switch the VSG from active power control priority mode to reactive power control priority mode during power system faults. The VSG dynamically adjusts the active power command value and reactive power command value to reduce the active power of the grid-type converter and increase the reactive power. The droop system adjustment unit is used to dynamically adjust the active power droop coefficient according to the degree of grid voltage drop, so as to realize the power system recovery after the fault is cleared.

7. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method as described in any one of claims 1-5.

8. A storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the method as described in any one of claims 1-5.

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