Direct drive fan GSC fault ride-through control method under balanced and unbalanced faults

Abstract

The invention relates to a direct-drive fan GSC fault ride-through control method under balanced and unbalanced faults, which comprises a non-fault GSC networking control module, a fault GSC fault ride-through control module and a power control module, and comprises the following steps of: detecting whether a fault occurs in the operation of a power grid, switching a fault mode signal Fm according to the operation condition of the power grid, when the power grid is in a normal operation or weak network condition, using a non-fault GSC networking control module, and enabling a power control module to operate normally; when a balanced or unbalanced fault occurs, the Fm is switched to the GSC fault ride-through control module under the fault, the power control module is bypassed by the Fm, corresponding voltage and current of the GSC are output under different power grid operation conditions, the current is effectively controlled within a safe range, and the voltage unbalance factor is reduced during the unbalanced power grid fault period. According to the method, the network construction capability of the direct-drive fan is enhanced, and the fault ride-through capability of the direct-drive fan under the balanced and unbalanced faults of the power grid is remarkably improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of grid-connected control and fault ride-through of wind power generation, and relates to a control method for grid-side converter (GSC) fault ride-through of a direct-drive wind turbine under balanced and unbalanced faults. Background Art

[0002] The direct-drive wind turbine is connected to the power grid through a grid-side converter (GSC). To solve the technical problem of insufficient stability of grid-following (GFL) under weak grid conditions, grid-forming (GFM) control, as a powerful alternative solution, has been widely studied and integrated into the GSC. Although GFM control improves the stability of weak power grids, it usually requires a large-capacity DC capacitor to provide sufficient inertia. In applications, it is crucial to control the DC link voltage because direct-drive wind turbines usually lack a large amount of energy storage on the DC side, and installing such energy storage will increase the cost and complexity of the system. Currently, some scholars have proposed an alternative control strategy that uses the machine-side converter (MSC) to manage the DC voltage, but grid faults still need to be considered, and challenges still remain in terms of transient response.

[0003] During grid faults, different from synchronous generators (SGs), SGs can manage significant overcurrents, while power converters can only withstand 20% to 40% of overcurrents. Trying to replicate the overcurrent capacity of SGs during large disturbances will require large semiconductor components, which will bring high additional costs. Therefore, power converters are designed to limit current during extreme events and also provide reactive current to help the power grid recover.

[0004] Considering the importance of limiting the converter current, the most effective method is to use a control method that adjusts the reference current and limits the overcurrent independently of the fault conditions. In a GFM converter, if current saturation is directly applied, the converter may work as a constant current source, resulting in loss of control of the terminal voltage and instability. To avoid this situation, a standby phase locked loop (PLL) is usually activated, but this may lead to power imbalance during fault recovery. Some studies have shown that even in the case of excessive current, the GFM converter should maintain its characteristics. Other studies suggest using virtual impedance to limit current, but the effectiveness of this method depends on factors such as the fault location and the selected virtual impedance, and it is easily limited in practical applications.

[0005] In summary, the existing direct-drive wind turbine GFM converters do not consider the stable operation and over-current limiting ability of the converter under grid faults, which may lead to system instability during faults and a decrease in the service life of the converter. Moreover, the existing over-current limiting methods also have certain limitations, and the GFM converter urgently needs to be further improved. Summary of the Invention

[0006] In view of the above existing problems, the present invention is proposed.

[0007] Therefore, the present invention provides a fault ride-through control method for the GSC of a direct-drive wind turbine under balanced and unbalanced faults, which can solve the problem that the existing direct-drive wind turbine GFM converter does not consider the stable operation and over-current limiting ability of the converter under grid faults.

[0008] To solve the above technical problems, the present invention provides the following technical solutions. The fault ride-through control method for the GSC of a direct-drive wind turbine under balanced and unbalanced faults includes:

[0009] A GSC grid-forming control module under non-fault conditions, a GSC fault ride-through control module under fault conditions, and a power control module;

[0010] The GSC grid-forming control module under non-fault conditions is used to improve the grid-forming ability of the direct-drive wind turbine when the grid is operating normally or in a weak grid condition;

[0011] The GSC fault ride-through control module under fault conditions is used to limit the over-current in the converter during balanced and unbalanced faults;

[0012] The power control module is used to keep the GSC synchronized with the grid.

[0013] As a preferred embodiment of the fault ride-through control method for the GSC of a direct-drive wind turbine under balanced and unbalanced faults according to the present invention, wherein: it is detected whether a fault occurs in the grid operation, and the judgment result is used to determine the fault mode signal F m .

[0014] As a preferred embodiment of the fault ride-through control method for the GSC of a direct-drive wind turbine under balanced and unbalanced faults according to the present invention, wherein: if the grid is operating normally or in a weak grid condition, the GSC grid-forming control module under non-fault conditions is selected through the fault mode signal F m , and the power control module operates normally; when a balanced or unbalanced fault occurs, it is switched to the GSC fault ride-through control module under fault conditions through F m , and the power control module is bypassed by F m .

[0015] As a preferred solution of the direct-drive wind turbine GSC fault ride-through control method under balanced and unbalanced faults described in the present invention, wherein: the dq-axis control input VsTdq(t) of the GSC grid-forming control module under non-fault conditions is obtained by the following formula:

[0016]

[0017] Wherein, L F is the filter inductor, R F is the filter resistor, I s Fdq is the dq-axis component of the current on the GSC side in the synchronous dq reference frame, ω s is the transformation phase derivative of the power control module, V s Gdq is the dq-axis component of the voltage on the filter capacitor side in the synchronous dq reference frame, and J is represented by the following formula:

[0018]

[0019] u idq represents the output of the proportional-integral module of the current control loop of the GSC grid-forming control module under non-fault conditions, and is represented by the following formula:

[0020]

[0021] Wherein, K p and K i are the proportional and integral gains of the current controller, is the reference value of I s Fdq and is represented by the following formula:

[0022]

[0023] Wherein, C F is the filter capacitor, I s Gdq is the dq-axis component of the current on the filter capacitor side in the synchronous dq reference frame, and u vdq represents the voltage control loop of the GSC grid-forming control module under non-fault conditions, and is represented by the following formula:

[0024]

[0025] Wherein, K iv and K pv are the proportional and integral gains of the voltage controller, is the reference value of V s Gdq .

[0026] As a preferred solution of the direct-drive wind turbine GSC fault ride-through control method under balanced and unbalanced faults described in the present invention, wherein: the dq-axis control input V of the GSC fault ride-through control module under the determined fault Tdq (t) is obtained by the following formula:

[0027]

[0028] Wherein, is the positive-sequence component of V Tdq (t) in the positive rotating coordinate system, representing the voltage component under balanced faults, is the positive-sequence component of V Tdq (t) in the negative rotating coordinate system, representing the voltage component under unbalanced faults.

[0029] As a preferred solution of the direct-drive wind turbine GSC fault ride-through control method under balanced and unbalanced faults described in the present invention, wherein: is represented by the following formula:

[0030]

[0031] Wherein, I Fdq is the dq-axis component of the GSC-side current in the synchronous dq reference frame under fault conditions, I * Fdq is the reference value of I Fdq , is represented by the following formula:

[0032]

[0033] Wherein, ω F is the output frequency of the power control module under fault conditions, T(2ω F ) is used for the conversion between the positive and negative reference frames and is represented by the following formula:

[0034]

[0035] is the negative-sequence component of V Tdq (t) in the negative rotating coordinate system and is represented by the following formula:

[0036]

[0037] Wherein, K pn is the proportional gain of the negative-sequence component of the voltage controller, I * Fdq(t) is represented by the following formula:

[0038]

[0039] Wherein, and are respectively represented by the following formulas:

[0040]

[0041] Wherein, and are respectively; and are respectively; V Gd+ and V Gq+ are respectively the positive sequence components of the d-axis and q-axis of the voltage on the filter capacitor side; V Gd- and V Gq- are respectively the negative sequence components of the d-axis and q-axis of the voltage on the filter capacitor side; V n Gd- and V n Gq- are respectively the negative sequence components of the d-axis and q-axis of the voltage on the filter capacitor side in the negative rotating reference frame; V n Gd+ and V n Gq+ are respectively the positive sequence components of the d-axis and q-axis of the voltage on the filter capacitor side in the negative rotating reference frame.

[0042] As a preferred scheme of the direct-drive wind turbine GSC fault ride-through control method under balanced and unbalanced faults according to the present invention, wherein: when the power grid is operating normally or in a weak grid condition, the power control module operates normally, and the generated dq transformation phase signal φ m (t) is represented by the following formula:

[0043]

[0044] Wherein, K m is the equivalent P-f voltage drop coefficient, ω N is the fundamental angular frequency of the power grid, P and P ref are respectively the active power and the active power reference, ω c is the cut-off frequency of the low-pass filter adopted by the power control module.

[0045] As a preferred scheme of the direct-drive wind turbine GSC fault ride-through control method under balanced and unbalanced faults according to the present invention, wherein: when a balanced or unbalanced fault occurs, the fault mode signal F m switches to the GSC fault ride-through control module under the fault, and the power control module is bypassed by F m . At this time, the power control module only maintains the output frequency ω F before the fault.

[0046] A computer device includes a memory and a processor. The memory stores a computer program. It is characterized in that when the processor executes the computer program, the steps of a direct-drive fan GSC fault ride-through control method under balanced and unbalanced faults are realized.

[0047] A computer-readable storage medium stores a computer program thereon. It is characterized in that when the computer program is executed by a processor, the steps of a direct-drive fan GSC fault ride-through control method under balanced and unbalanced faults are realized.

[0048] Advantages of the present invention: Under different grid operating conditions, the present invention realizes the output of corresponding voltages and currents of the GSC by switching different control modules, effectively controls the current within a safe range, and reduces voltage imbalance factors during unbalanced grid faults. The method of the present invention not only enhances the grid-forming ability of the direct-drive fan but also significantly improves the fault ride-through ability of the direct-drive fan under balanced and unbalanced faults in the power grid. Description of the Drawings

[0049] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for description in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0050] Figure 1 This is the GSC grid-forming control module under non-fault conditions and the power control loop under non-fault conditions involved in the present invention.

[0051] Figure 2 This is the direct-drive fan GSC control under fault and non-fault conditions and the power control loop under fault conditions involved in the present invention. Detailed Embodiments

[0052] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following detailed description of the specific embodiments of the present invention will be made in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, not all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0053] Many specific details are set forth in the following description to facilitate a full understanding of the present invention. However, the present invention can also be implemented in other ways different from those described herein. Those skilled in the art can make similar generalizations without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0054] Second, the so-called "one embodiment" or "embodiment" herein refers to specific features, structures or characteristics that may be included in at least one implementation manner of the present invention. The appearances of "in one embodiment" in different places in this specification do not all refer to the same embodiment, nor are they separate or alternative embodiments that are mutually exclusive with other embodiments.

[0055] The present invention will be described in detail in conjunction with schematic diagrams. When describing the embodiments of the present invention in detail, for the convenience of explanation, the cross-sectional views showing the device structure will be enlarged locally in a non-general proportion, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention herein. In addition, in actual production, three-dimensional spatial dimensions of length, width and depth should be included.

[0056] At the same time, in the description of the present invention, it should be noted that the orientation or positional relationship indicated by terms such as "upper, lower, inner and outer" is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention. In addition, the terms "first, second or third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0057] Unless otherwise clearly defined and limited in the present invention, the terms "mounted, connected, connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection or an integral connection; it can also be a mechanical connection, an electrical connection or a direct connection, and can also be indirectly connected through an intermediate medium, or can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0058] Embodiment 1, referring to Figure 1 - Figure 2 , which is the first embodiment of the present invention. This embodiment provides a direct-drive fan GSC fault ride-through control method under balanced and unbalanced faults, including:

[0059] Figure 1 The GSC grid-forming control module and the power control loop under non-fault conditions, including the current control loop under non-fault conditions, the voltage control loop, the power control loop under non-fault conditions, the abc-dq coordinate system converter and the PWM modulation signal generator. Among them, the GSC grid-forming control module under non-fault conditions includes the current control loop and the voltage control loop under non-fault conditions. The specific implementation steps of the current control loop under non-fault conditions, the voltage control loop and the power control loop under non-fault conditions include:

[0060] Determine the dq-axis control input of the GSC grid-forming control module under non-fault conditions in the current control loop under non-fault conditions Obtained from the following formula:

[0061]

[0062] Among them, L F is the filter inductor, R F is the filter resistor, is the dq-axis component of the GSC-side current in the synchronous dq reference frame, ω s is the transformation phase derivative of the power control module, is the dq-axis component of the voltage on the filter capacitor side in the synchronous dq reference frame, and J is expressed by the following formula:

[0063]

[0064] u idq represents the output of the proportional-integral module of the current control loop of the GSC grid-forming control module under non-fault conditions, and is expressed by the following formula:

[0065]

[0066] Among them, in the voltage control loop, K p and K i are the proportional and integral gains of the current controller, is 's reference value, and is expressed by the following formula:

[0067]

[0068] Among them, C F is the filter capacitor, is the dq-axis component of the current on the filter capacitor side in the synchronous dq reference frame, u vdq represents the voltage control loop of the GSC grid-forming control module under non-fault conditions, and is expressed by the following formula:

[0069]

[0070] Among them, K iv and K pv are the proportional and integral gains of the voltage controller, is 's reference value.

[0071] Figure 2For the GSC control in the case of faults and non-faults and the power control loop in the case of faults, it includes the GSC fault ride-through control module in the case of faults, the GSC grid-forming control module in the case of non-faults, the power control loop in the case of faults, the abc-dq coordinate system converter, and the PWM modulation signal generator. Among them, the GSC fault ride-through control module in the case of faults includes the current control loop in the case of faults, the dq current reference value generation module, the dq current reference value generation module, the current limit value setting module, and the active and reactive current reference value setting module. The specific implementation steps of the GSC fault ride-through control module in the case of faults, the GSC grid-forming control module in the case of non-faults, and the power control loop in the case of faults include:

[0072] Determine the dq-axis control input V of the GSC fault ride-through control module in the case of faults Tdq (t) is obtained by the following formula:

[0073]

[0074] Among them, in the current control loop in the case of faults, is the positive sequence component of V Tdq (t) in the positive rotating coordinate system, representing the voltage component under balanced faults, is the positive sequence component of V Tdq (t) in the negative rotating coordinate system, representing the voltage component under unbalanced faults, is represented by the following formula:

[0075]

[0076] Among them, I Fdq is the dq-axis component of the GSC-side current in the synchronous dq reference system in the case of faults, is the reference value of I Fdq , is represented by the following formula:

[0077]

[0078] Among them, ω F is the output frequency of the power control module in the case of faults, T(2ω F ) is used for the conversion between the positive and negative reference systems and is represented by the following formula:

[0079]

[0080] is the negative sequence component of V Tdq (t) in the negative rotating coordinate system and is represented by the following formula:

[0081]

[0082] Among them, Kpn is the proportional gain of the negative sequence component of the voltage controller. It is expressed by the following formula:

[0083]

[0084] wherein, in the dq current reference value generation module, and are respectively expressed by the following formulas:

[0085]

[0086] wherein, and are the instantaneous active and reactive positive sequence current limits and negative sequence current limits respectively, V Gdq+ is the positive sequence component of the dq axis of the voltage on the filter capacitor side, is the negative sequence component of the dq axis of the voltage on the filter capacitor side in the negative rotation reference frame. In the current limit value setting module, and are determined by the following algorithm:

[0087]

[0088]

[0089] wherein, in the active and reactive current reference value setting module, and are the active and reactive positive sequence currents and negative sequence currents respectively, I max is the converter current limit value. and are respectively expressed by the following formulas:

[0090]

[0091] wherein, V n and I n are the nominal grid voltage and the converter current, V0 is the voltage before the fault, V GM+ is the positive sequence grid voltage amplitude, V GM- is the negative grid voltage amplitude, K1 and K2 represent proportionality coefficients, which are usually set according to the grid specifications.

[0092] Moreover, in the power control loop, when the grid is operating normally or in a weak grid situation, the power control module operates normally, and the dq transformation phase signal φ m (t) is expressed by the following formula:

[0093]

[0094] wherein, K mis the equivalent P-f voltage drop coefficient, ω N is the fundamental angular frequency of the power grid, and P and P ref are the active power and the active power reference respectively, ω c is the cut-off frequency of the low-pass filter adopted by the power control module.

[0095] Through the above full process including the GSC grid-forming control module under non-fault conditions, the GSC fault-ride-through control module under fault conditions, and the power control loop, it is possible to achieve switching different control modules under different power grid operating conditions, output the corresponding voltage and current of the GSC, effectively control the current within a safe range, and reduce the voltage imbalance factor during unbalanced power grid faults.

[0096] The present invention solves the technical problems of the stable operation of the converter and the improvement of the over-current limiting ability of the existing direct-drive wind turbine grid-forming (GFM) converter under power grid faults, can effectively avoid system instability during faults and effectively improve the service life of the converter, and further improves the limitations of the existing over-current limiting method for GFM converters. The method of the present invention inherits the advantages of the existing GFM converter. By considering the converter control method under faults and the fault-ride-through methods of the converter under balanced and unbalanced faults, the stable operation ability of the GFM converter under different power grid operating conditions is significantly improved. The process is as follows: first, detect whether a fault occurs in the power grid operation, and then switch the fault mode signal F according to the power grid operating conditions m . When the power grid is operating normally or in a weak grid condition, the GSC grid-forming control module under non-fault conditions is used, and the power control module operates normally. When a balanced or unbalanced fault occurs, switch to the GSC fault-ride-through control module under fault conditions through F m , and the power control module is bypassed by F m . In this way, the corresponding voltage and current of the GSC are output under different power grid operating conditions, the current is effectively controlled within a safe range, and the voltage imbalance factor is reduced during unbalanced power grid faults. The method of the present invention not only enhances the grid-forming ability of the direct-drive wind turbine, but also significantly improves the fault-ride-through ability of the direct-drive wind turbine under balanced and unbalanced power grid faults.

[0097] Embodiment 2

[0098] The second embodiment of the present invention is different from the previous embodiment in that:

[0099] If the above-mentioned functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The foregoing storage medium includes: various media that can store program codes, such as USB flash drives, mobile hard disks, read-only memories (ROMs), random access memories (RAMs), magnetic disks, or optical discs.

[0100] This application is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram, and the combination of flows and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0101] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in this computer-readable memory generate a manufactured article including instruction means, and the instruction means implements the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0102] These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process. Thus, the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0103] Although the preferred embodiments of the present application have been described, additional changes and modifications can be made to these embodiments by those skilled in the art once they learn the basic creative concept. Therefore, the appended claims are intended to be interpreted to include the preferred embodiments as well as all changes and modifications that fall within the scope of the present application.

[0104] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application is also intended to include these modifications and variations.

Claims

1. A GSC fault ride-through control method for a direct-drive wind turbine under balanced and unbalanced faults, characterized in that: include, GSC network construction control module under normal conditions, GSC fault ride-through control module under fault conditions, and power control module; The GSC network control module under non-fault conditions is used to improve the network construction capability of the direct-drive wind turbine when the power grid is operating normally or in a weak network condition; The GSC fault ride-through control module under fault is used to limit the overcurrent in the converter during balanced and unbalanced faults; The power control module is used to keep the GSC synchronized with the grid.

2. The GSC fault ride-through control method for a direct-drive wind turbine under balanced and unbalanced faults according to claim 1, characterized in that: Detect whether there is a fault in the power grid operation, and the judgment result is used to determine the fault mode signal F m .

3. The GSC fault ride-through control method for direct-drive wind turbines under balanced and unbalanced faults according to claim 2, characterized in that: If the power grid is operating normally or in a weak grid condition, the fault mode signal F m Select the GSC network control module under non-fault conditions, and the power control module operates normally; when a balanced or unbalanced fault occurs, m Switch to the GSC fault ride-through control module under fault, and the power control module is F m bypass.

4. The GSC fault ride-through control method for direct-drive wind turbines under balanced and unbalanced faults according to claim 3, characterized in that: The dq axis control input V sTdq(t) of the GSC network control module under the non-fault condition is obtained by the following formula: Among them, L F is the filter inductor, R F is the filter resistor, I s Fdq is the dq axis component of the current at the GSC side in the synchronous dq reference frame, ω s is the transformation phase derivative of the power control module, V s Gdq is the dq-axis component of the voltage on the filter capacitor side in the synchronous dq reference system, and J is expressed by the following formula: u idq The output of the proportional integral module of the current control loop of the GSC network control module under non-fault conditions is represented by the following formula: Among them, K p and K i are the proportional and integral gains of the current controller, for The reference value is expressed by the following formula: Among them, C F is the filter capacitor, I s Gdq is the dq axis component of the current on the filter capacitor side in the synchronous dq reference frame, u vdq The voltage control loop of the GSC network control module under non-fault conditions is represented by the following formula: Among them, K iv and K pv are the proportional and integral gains of the voltage controller, for reference value.

5. The GSC fault ride-through control method for direct-drive wind turbines under balanced and unbalanced faults according to claim 4, characterized in that: The GSC fault-crossing control module dq axis control input V under the determined fault Tdq (t) is obtained from the following formula: in, V Tdq (t) is the positive sequence component in the positive rotating coordinate system, representing the voltage component under balanced fault, V Tdq (t) The positive sequence component in the negative rotating coordinate system represents the voltage component under unbalanced fault.

6. The GSC fault ride-through control method for direct-drive wind turbines under balanced and unbalanced faults according to claim 5, characterized in that: It is expressed by the following formula: Among them, I Fdq is the dq axis component of the current on the GSC side in the synchronous dq reference frame under fault conditions, For I Fdq The reference value of It is expressed by the following formula: Among them, ω F is the output frequency of the power control module in the event of a fault, T(2ω F ) is used for conversion between positive and negative reference frames and is expressed as follows: V Tdq (t) The negative sequence component in the negative rotating coordinate system is expressed by the following formula: Among them, K pn is the proportional gain of the negative sequence component of the voltage controller, I * Fdq(t) It is expressed by the following formula: in, and They are expressed by the following formulas: in, and They are; and They are: V Gd+ and V Gq+ are the d-axis and q-axis positive sequence components of the voltage on the filter capacitor side respectively; V Gd- and V Gq- are the d-axis and q-axis negative sequence components of the voltage on the filter capacitor side respectively; V n Gd- and V n Gq- are the d-axis and q-axis negative sequence components of the voltage on the filter capacitor side in the negative rotating reference frame; V n Gd+ and V n Gq+ They are respectively the d-axis and q-axis positive sequence components of the voltage on the filter capacitor side in the negative rotating reference frame.

7. The GSC fault ride-through control method for a direct-drive wind turbine under balanced and unbalanced faults according to claim 6, characterized in that: When the power grid is operating normally or in a weak grid condition, the power control module operates normally and the generated dq conversion phase signal φ m (t) is represented by the following formula: Among them, K m is the equivalent Pf pressure drop coefficient, ω N is the grid fundamental angular frequency, P and P ref are active power and active power reference respectively, ω c It is the cutoff frequency of the low-pass filter used by the power control module.

8. The GSC fault ride-through control method for a direct-drive wind turbine under balanced and unbalanced faults according to claim 7, characterized in that: When a balanced or unbalanced fault occurs, the fault mode signal F m Switch to the GSC fault ride-through control module under fault, and the power control module is F m Bypass, at this time, the power control module only maintains the output frequency ω before the fault F .

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 8 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 8 are implemented.

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