Method and control device for suppressing fault differential pressure of doubly-fed wind turbine

Abstract

The application is suitable for the field of doubly-fed wind turbine grid-connection technology, and provides a doubly-fed wind turbine fault voltage difference suppression method and a control device. The method comprises the following steps: after detecting voltage drop of the doubly-fed wind turbine, parameters of the doubly-fed wind turbine are obtained, the parameters comprising stator current, rotor current, grid-connection point voltage, stator winding self-inductance, mutual inductance, rotor angular frequency and power grid angular frequency; based on the parameters, a stator current transient component is calculated; based on the stator current transient component, a voltage difference suppression term is calculated; based on the voltage difference suppression term, a control voltage given value is obtained; and the control voltage given value is transmitted to a rotor converter to adjust a control voltage output value of the rotor converter. The application can offset the change of rotor transient induced electromotive force, effectively suppress the rotor current, and significantly improve the fault ride-through performance of the doubly-fed wind turbine.

Description

Technical Field

[0001] This application belongs to the field of doubly fed wind turbine grid connection technology, and particularly relates to a method and control device for suppressing fault differential pressure in doubly fed wind turbines. Background Technology

[0002] Doubly fed induction generators (DFIGs) offer advantages such as variable speed operation, high wind energy conversion efficiency, independent decoupling control of active and reactive power, and low converter cost. However, the stator side of a DFIG is directly connected to the grid. When a grid fault occurs, the rotor windings are prone to overcurrent, which can cause the turbine to disconnect from the grid. Currently, DFIGs mainly improve fault ride-through performance by weakening stator transient flux linkage and suppressing overcurrent. A control strategy that suppresses the transient back EMF of the converter's control voltage through flux linkage effectively suppresses rotor overcurrent during faults, achieving good suppression results at different fault depths. However, flux linkage monitoring technology is complex and difficult to implement in engineering. Therefore, it is necessary to find a fault ride-through method that can avoid flux linkage monitoring. Summary of the Invention

[0003] This application provides a method and control device for suppressing fault differential pressure in doubly-fed wind turbines to improve the fault ride-through performance of doubly-fed wind turbines.

[0004] This application is achieved through the following technical solution:

[0005] In a first aspect, embodiments of this application provide a method for suppressing fault differential pressure in a doubly-fed wind turbine, including:

[0006] When a voltage drop is detected in the doubly fed wind turbine, the parameters of the doubly fed wind turbine are obtained, including: stator current, rotor current, grid connection point voltage, stator winding self-inductance, mutual inductance, rotor angular frequency, and grid angular frequency.

[0007] Based on the parameters, the transient components of the stator current are calculated.

[0008] The differential pressure suppression term is calculated based on the transient component of the stator current.

[0009] The control voltage setpoint is obtained based on the differential pressure suppression term.

[0010] The control voltage setpoint is transmitted to the rotor converter to adjust the control voltage output value of the rotor converter.

[0011] In conjunction with the first aspect, in some possible implementations, the differential voltage suppression term is calculated based on the transient component of the stator current, including:

[0012] The transient component of rotor induced electromotive force is calculated based on the transient component of stator current, grid angular frequency, and mutual inductance.

[0013] The differential pressure suppression term is calculated based on the transient component of the rotor induced electromotive force and the suppression coefficient.

[0014] In conjunction with the first aspect, in some possible implementations, the transient component of the stator current is calculated using the following formula:

[0015]

[0016] Among them, i sfn i is the transient component of the stator current. sf For stator current, i rf For rotor current, u s L is the grid connection point voltage. s For the stator winding self-inductance, L m For mutual inductance, ω s This is the angular frequency of the power grid.

[0017] In conjunction with the first aspect, in some possible implementations, the transient component of the rotor induced electromotive force is calculated using the following formula:

[0018] e ron =-jω r L m i sfn

[0019] Where, ω r L is the angular frequency of the power grid. m For mutual induction, i sfn This refers to the transient component of the stator current.

[0020] In conjunction with the first aspect, in some possible implementations, the differential pressure suppression term is calculated using the following formula:

[0021] u rn =k c e ron

[0022] Where, k c e is the suppression coefficient. ron This represents the transient component of the rotor induced electromotive force.

[0023] In conjunction with the first aspect, in some possible implementations, the control voltage setpoint is obtained based on the differential pressure suppression term, including:

[0024] The control voltage setpoint is obtained based on the voltage output from the differential pressure suppression term and the rotor current via PI regulation.

[0025] In conjunction with the first aspect, in some possible implementations, the control voltage setpoint is calculated using the following formula:

[0026]

[0027] Among them, urw The voltage output by the rotor current through PI regulation, u rn This is the differential pressure suppression term.

[0028] In conjunction with the first aspect, in some possible implementations, the control voltage setpoint is transmitted to the rotor converter to regulate the control voltage output value of the rotor converter. The method also includes:

[0029] If a voltage drop is detected in the doubly fed fan, the doubly fed fan is connected to the unloading circuit, which is used to reduce the rotor current of the doubly fed fan.

[0030] In a second aspect, embodiments of this application provide a control device, including: a processor and a memory, the memory being used to store a computer program, wherein the processor executes the computer program to implement the doubly fed fan fault differential pressure suppression method as described in any of the first aspects.

[0031] Thirdly, embodiments of this application provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements the doubly-fed fan fault differential pressure suppression method as described in any of the first aspects.

[0032] Fourthly, embodiments of this application provide a computer program product that, when run on a control device, causes the control device to execute the doubly fed fan fault differential pressure suppression method described in any of the first aspects.

[0033] It is understood that the beneficial effects of the second to fourth aspects mentioned above can be found in the relevant descriptions in the first aspect mentioned above, and will not be repeated here.

[0034] The beneficial effects of the embodiments in this application compared with the prior art are:

[0035] This application obtains the parameters of a doubly-fed induction generator (DFIG) after a voltage drop and an increase in rotor current. It then obtains the parameters of the stator, which is coupled with the rotor. Because the stator and rotor are coupled, the voltage difference suppression term can be calculated by calculating the transient current component of the stator. Based on the voltage difference suppression term, the control voltage setpoint is obtained. The control voltage setpoint changes the control voltage output value of the rotor converter, which cancels the change in the transient induced electromotive force of the rotor and achieves effective suppression of the rotor current, thereby improving the fault ride-through performance of the DFIG.

[0036] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this specification. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of this application, 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 of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is a schematic diagram illustrating an application scenario of the doubly fed fan fault differential pressure suppression method provided in an embodiment of this application;

[0039] Figure 2 This is a schematic flowchart of a method for suppressing fault pressure difference in a doubly fed wind turbine according to an embodiment of this application;

[0040] Figure 3 This is a rotor equivalent circuit diagram provided in one embodiment of this application;

[0041] Figure 4 This is a block diagram of a method for suppressing fault differential pressure in a doubly-fed wind turbine according to an embodiment of this application;

[0042] Figure 5 This is a schematic diagram of a wind farm grid connection simulation system provided in one embodiment of this application;

[0043] Figure 6 This is a comparison diagram of the changes in grid connection points between the method of the present invention and the conventional control method provided in an embodiment of this application;

[0044] Figure 7 This is a comparison diagram of the changes in grid connection points between the method of the present invention and the conventional control method provided in another embodiment of this application;

[0045] Figure 8 This is a schematic diagram of the structure of a doubly fed fan fault differential pressure suppression device provided in an embodiment of this application;

[0046] Figure 9 This is a schematic diagram of the structure of a control device provided in an embodiment of this application. Detailed Implementation

[0047] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0048] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0049] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0050] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if detected [the described condition or event]" may be interpreted, depending on the context, as meaning "once determined," "in response to determination," "once detected [the described condition or event]," or "in response to detection [the described condition or event]."

[0051] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0052] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0053] For example, embodiments of this application can be applied to, for example... Figure 1 In the exemplary scenario shown, the doubly-fed induction generator (DFIG) parameter acquisition device 10 acquires the parameters of the DFIG after detecting a voltage drop and an increase in rotor current. These parameters are then transmitted to the DFIG fault differential pressure suppression device 20. The DFIG fault differential pressure suppression device 20 calculates the control voltage setpoint based on the DFIG parameters and transmits the control voltage setpoint to the inverter, thereby improving the fault ride-through performance of the DFIG.

[0054] The following combination Figure 1The method for suppressing fault pressure difference in doubly fed wind turbines in this application is described in detail.

[0055] Figure 2 This is a schematic flowchart of a method for suppressing differential pressure during a doubly-fed wind turbine fault, provided in an embodiment of this application. (Refer to...) Figure 2 The method for suppressing fault differential pressure in this doubly-fed induction generator is described in detail below:

[0056] Step 101: After a voltage drop is detected in the doubly-fed induction generator (DFIG), the parameters of the DFIG are obtained.

[0057] For example, the parameters include: stator current, rotor current, grid connection point voltage, stator winding self-inductance, mutual inductance, rotor angular frequency, and grid angular frequency.

[0058] Specifically, the stator side of a doubly-fed induction generator (DFIG) is directly connected to the power grid. When a grid fault occurs, according to the principle of flux linkage conservation, a transient component will be induced in the stator flux linkage. Due to the coupling relationship between the stator and rotor, this transient component of the stator flux linkage will generate a large-amplitude rotor transient induced electromotive force in the rotor windings. For example... Figure 3 As shown, the rotor transient induced electromotive force This is applied to the rotor circuit, and at this time the rotor-side converter RSC control voltage... Unable to respond to rotor induced electromotive force in a timely manner The change in voltage increases the differential pressure, which in turn increases the rotor current. To prevent damage to the converter equipment, the fan will disconnect from the grid.

[0059] Step 102: Calculate the transient component of the stator current based on the parameters; calculate the differential voltage suppression term based on the transient component of the stator current; obtain the control voltage setpoint based on the differential voltage suppression term.

[0060] For example, the differential pressure suppression term is calculated based on the transient component of the stator current, including: calculating the transient component of the rotor induced electromotive force based on the transient component of the stator current, the grid angular frequency, and the mutual inductance; and calculating the differential pressure suppression term based on the transient component of the rotor induced electromotive force and the suppression coefficient.

[0061] For example, the transient component of the stator current is calculated using the following formula:

[0062]

[0063] Among them, i sfn i is the transient component of the stator current. sf For stator current, i rf For rotor current, u s L is the grid connection point voltage. s For the stator winding self-inductance, L m For mutual inductance, ω s This is the angular frequency of the power grid.

[0064] For example, the transient component of the rotor induced electromotive force is calculated by the following formula:

[0065] e ron =-jω r L m i sfn (2)

[0066] Where, ω r L is the angular frequency of the power grid. m For mutual induction, i sfn This refers to the transient component of the stator current.

[0067] For example, the differential pressure suppression term is calculated using the following formula:

[0068] u rn =k c e ron (3)

[0069] Where, k c e is the suppression coefficient. ron This represents the transient component of the rotor induced electromotive force.

[0070] Specifically, when k c =1, which can achieve complete suppression of the rotor transient induced electromotive force. Under the condition of complete suppression, since the rotor potential and voltage still maintain a constant voltage difference, the rotor current can theoretically remain unchanged. When k c When k < 1, the rotor transient induced electromotive force is in an under-suppressed state, and the effect of suppressing rotor overcurrent is weaker than that of full suppression; when k c When the value is greater than 1, the rotor transient induced electromotive force is in an over-suppressed state, which usually does not occur in actual control.

[0071] For example, obtaining the control voltage setpoint based on the differential pressure suppression term includes: obtaining the control voltage setpoint based on the voltage output by PI regulation of the rotor current and the differential pressure suppression term.

[0072] For example, the control voltage setpoint is calculated using the following formula:

[0073]

[0074] Among them, u rw The voltage output by the rotor current through PI regulation, u rn This is the differential pressure suppression term.

[0075] Step 103: The control voltage setpoint is transmitted to the rotor converter to adjust the control voltage output value of the rotor converter.

[0076] For example, transmitting a control voltage setpoint to the rotor converter to regulate the control voltage output value of the rotor converter, the method further includes:

[0077] If a voltage drop is detected in the doubly fed fan, the doubly fed fan is connected to the unloading circuit, which is used to reduce the rotor current of the doubly fed fan.

[0078] Specifically, while differential voltage suppression control can suppress rotor current, it also increases the control voltage of the rotor converter, which cannot exceed its maximum value. In the event of a significant voltage drop, the rotor transient induced electromotive force is difficult to completely suppress, and a load shedding circuit is still required to prevent rotor current damage to the equipment.

[0079] like Figure 4 As shown, I sdq I rdq U sdq i sf i rf u s d-axis and q-axis components; e rd e rq For e ron The d-axis and q-axis components. Rotor current I rdq Stator current I sdq Stator voltage U sdq The transient component I of the stator current is calculated from equation (1). sfn Then, the rotor transient induced electromotive force e is calculated using equation (2). rd e rq After the proportional process, it is added to u rwd u rwq The control voltage of the converter can be obtained from the above. The d-axis and q-axis components are transformed by coordinates and then processed by a PWM generator to obtain a three-phase PWM modulation signal, which is applied to the rotor converter to suppress the voltage difference between the converter control voltage and the rotor induced electromotive force and reduce the rotor current.

[0080] The aforementioned method for suppressing differential voltage during doubly-fed induction generator (DFIG) faults obtains the parameters of the DFIG after a voltage drop and an increase in rotor current. This yields the parameters of the stator, which is coupled with the rotor. Because of the coupling between the stator and rotor, the differential voltage suppression term can be calculated by calculating the transient current component of the stator. Based on the differential voltage suppression term, the control voltage setpoint is obtained. This control voltage setpoint changes the control voltage output value of the rotor converter, offsetting the change in the transient induced electromotive force of the rotor and effectively suppressing the rotor current. This, in turn, improves the fault ride-through performance of the DFIG.

[0081] To verify the feasibility of the solution, a system was built as follows: Figure 5The simulation system for a wind farm grid connection shown includes 30 doubly-fed induction generator (DFIG) wind turbines with a capacity of 2MW each. The DFIGs are connected to an infinite power grid via two transformer stages. The basic parameters of the simulation model are shown in Table 1.

[0082] Table 1 Basic parameters of the simulation model

[0083]

[0084] Example 1: Figure 5 and Figure 6 As shown in (a), a three-phase ground fault lasting 0.2s occurs at bus B2 at 1s. During the fault process, according to the wind turbine grid connection criteria, the doubly-fed induction generator (DFIG) adopts active power reduction control, and the system's dynamic response... Figure 6 As shown, the voltage drop depth is 25% in 1 second. Without additional control, the rotor current increases and decreases as the rotor transient induced electromotive force decays, posing a risk of overcurrent. When the differential voltage suppression control based on the transient component of the stator current proposed in this paper is used, the rotor transient induced electromotive force is offset. At this time, the fault depth is lighter and full suppression can be achieved, completely offsetting the rotor transient induced electromotive force, and the rotor current remains almost unchanged.

[0085] Example 2: Figure 7 As shown, the voltage drop depth is 60%. Within 1 second, the voltage drops to 0.4 pu, indicating a deeper fault. The rotor current overcurrent value increases accordingly, and the rotor transient induced electromotive force also increases. Due to the limitation of the rotor converter's RSC voltage output capability, only a portion of the rotor transient induced electromotive force can be offset. For example... Figure 7 As shown in (e)(f), the control voltage u of the converter at 1.2s rd is 0.8pu,u rq It is 0.57 pu, and the calculated u r The value is 0.98 pu, close to the rated value. Without additional control, the maximum rotor current reaches 1.94 pu, while after adopting the doubly-fed fan fault differential pressure suppression method, the maximum rotor current is 1.4 pu, and the rotor current peak value is effectively suppressed. Without additional control, the rotor current and its d-axis and q-axis components fluctuate greatly, while after adopting the doubly-fed fan fault differential pressure suppression method, the rotor current fluctuation is very small.

[0086] Test results show that the fault differential pressure suppression method of the doubly fed wind turbine in this application can effectively suppress overcurrent, reduce the damage of faults to the wind turbine converter, and improve the fault ride-through capability of the wind turbine.

[0087] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0088] Corresponding to the doubly fed fan fault differential pressure suppression method described in the above embodiments, Figure 8 The diagram shows a structural block diagram of the doubly fed wind turbine fault differential pressure suppression device provided in the embodiments of this application. For ease of explanation, only the parts related to the embodiments of this application are shown.

[0089] See Figure 8 The doubly fed fan fault differential pressure suppression device in this embodiment may include an acquisition module 301, a calculation module 302, and a processing module 303.

[0090] Optionally, module 301 is used to acquire parameters of the doubly-fed wind turbine after a voltage drop is detected.

[0091] For example, the parameters include: stator current, rotor current, grid connection point voltage, stator winding self-inductance, mutual inductance, rotor angular frequency, and grid angular frequency.

[0092] Optionally, the calculation module 302 is used to calculate the transient component of the stator current based on the parameters; calculate the differential voltage suppression term based on the transient component of the stator current; and obtain the control voltage setpoint based on the differential voltage suppression term.

[0093] For example, the differential pressure suppression term is calculated based on the transient component of the stator current, including: calculating the transient component of the rotor induced electromotive force based on the transient component of the stator current, the grid angular frequency, and the mutual inductance; and calculating the differential pressure suppression term based on the transient component of the rotor induced electromotive force and the suppression coefficient.

[0094] For example, the transient component of the stator current is calculated using the following formula:

[0095]

[0096] Among them, i sfn i is the transient component of the stator current. sf For stator current, i rf For rotor current, u s L is the grid connection point voltage. s For the stator winding self-inductance, L m For mutual inductance, ω s This is the angular frequency of the power grid.

[0097] For example, the transient component of the rotor induced electromotive force is calculated by the following formula:

[0098] e ron =-jω r L m i sfn

[0099] Where, ω r L is the angular frequency of the power grid. m For mutual induction, isfn This refers to the transient component of the stator current.

[0100] For example, the differential pressure suppression term is calculated using the following formula:

[0101] u rn =k c e ron

[0102] Where, k c e is the suppression coefficient. ron This represents the transient component of the rotor induced electromotive force.

[0103] For example, obtaining the control voltage setpoint based on the differential pressure suppression term includes: obtaining the control voltage setpoint based on the voltage output by PI regulation of the rotor current and the differential pressure suppression term.

[0104] For example, the control voltage setpoint is calculated using the following formula:

[0105]

[0106] Among them, u rw The voltage output by the rotor current through PI regulation, u rn This is the differential pressure suppression term.

[0107] Optionally, the processing module 303 is used to transmit the control voltage setpoint to the rotor converter to adjust the control voltage output value of the rotor converter.

[0108] For example, the processing module 303 is also configured to control the doubly fed fan to connect to the unloading circuit if a voltage drop is detected in the doubly fed fan, the unloading circuit being used to reduce the rotor current of the doubly fed fan.

[0109] It should be noted that the information interaction and execution process between the above-mentioned devices / units are based on the same concept as the method embodiments of this application. For details on their specific functions and technical effects, please refer to the method embodiments section, and they will not be repeated here.

[0110] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0111] This application also provides a control device, see [link to relevant documentation] Figure 9 The control device 500 may include at least one processor 510 and a memory 520, the memory 520 being used to store a computer program 521. The processor 510 is used to call and run the computer program 521 stored in the memory 520 to implement the steps in any of the above method embodiments, for example... Figure 2 Steps 101 to 103 in the illustrated embodiment. Alternatively, when the processor 510 executes the computer program, it implements the functions of each module / unit in the above-described device embodiments, for example... Figure 8 The functions of modules 301 to 303 are shown.

[0112] For example, computer program 521 may be divided into one or more modules / units, one or more of which are stored in memory 520 and executed by processor 510 to complete this application. The one or more modules / units may be a series of computer program segments capable of performing specific functions, which describe the execution process of the computer program in control device 500.

[0113] Those skilled in the art will understand that Figure 9 This is merely an example of a control device and does not constitute a limitation on the control device. It may include more or fewer components than shown, or combine certain components, or different components, such as input / output devices, network access devices, buses, etc.

[0114] The processor 510 can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor.

[0115] The memory 520 can be an internal storage unit of the control device or an external storage device, such as a plug-in hard drive, a smart media card (SMC), a secure digital card (SD), or a flash card. The memory 520 is used to store the computer program and other programs and data required by the control device. The memory 520 can also be used to temporarily store data that has been output or will be output.

[0116] The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of illustration, the buses shown in the accompanying drawings are not limited to a single bus or a single type of bus.

[0117] The doubly fed fan fault differential pressure suppression method provided in this application embodiment can be applied to doubly fed fan fault differential pressure suppression devices, doubly fed fan fault detection, computers and other control devices. This application embodiment does not impose any restrictions on the specific type of control device.

[0118] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps in the various embodiments of the doubly fed fan fault differential pressure suppression method described above.

[0119] This application provides a computer program product that, when run on a mobile control device, enables the mobile control device to implement the steps in the various embodiments of the doubly fed fan fault differential pressure suppression method described above.

[0120] If the integrated unit is implemented as 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, all or part of the processes in the methods of the above embodiments of this application can be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include at least: any entity or device capable of carrying the computer program code to the photographing device / control device, a recording medium, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium, such as a USB flash drive, a portable hard drive, a magnetic disk, or an optical disk.

[0121] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0122] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0123] In the embodiments provided in this application, it should be understood that the disclosed apparatus / network devices and methods can be implemented in other ways. For example, the apparatus / network device embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0124] The units described as separate components may or may not be physically separate. The 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 the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0125] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A method for suppressing fault differential pressure in a doubly-fed induction generator (DFIG), characterized in that, include: When a voltage drop is detected in the doubly fed wind turbine, the parameters of the doubly fed wind turbine are obtained, including: stator current, rotor current, grid connection point voltage, stator winding self-inductance, mutual inductance, rotor angular frequency and grid angular frequency. Based on the parameters, the transient component of the stator current is calculated; the transient component of the stator current is calculated using the following formula: in, isfn This refers to the transient component of the stator current. isf For stator current, irf For rotor current, us The voltage at the grid connection point. Ls For the stator winding self-inductance Lm For mutual intuition, ωs The angular frequency of the power grid; Based on the stator current transient component, the grid angular frequency, and the mutual inductance, the rotor induced electromotive force transient component is calculated; the rotor induced electromotive force transient component is calculated using the following formula: in, ωr The angular frequency of the power grid. Lm For mutual intuition, isfn This refers to the transient component of the stator current. Based on the transient component of the rotor induced electromotive force and the suppression coefficient, the differential pressure suppression term is calculated; The control voltage setpoint is obtained based on the differential pressure suppression term; The control voltage setpoint is transmitted to the rotor converter to adjust the control voltage output value of the rotor converter.

2. The method for suppressing differential pressure during doubly-fed wind turbine failures as described in claim 1, characterized in that, The differential pressure suppression term is calculated using the following formula: in, kc The suppression coefficient, This represents the transient component of the rotor induced electromotive force.

3. The method for suppressing differential pressure during doubly-fed wind turbine failures as described in claim 1, characterized in that, The process of obtaining the control voltage setpoint based on the differential pressure suppression term includes: The control voltage setpoint is obtained based on the voltage output from the differential pressure suppression term and the rotor current via PI regulation.

4. The method for suppressing differential pressure during doubly-fed wind turbine failures as described in claim 1, characterized in that, The control voltage setpoint is calculated using the following formula: in, urw The output voltage is the rotor current adjusted by a PI controller. urn This is the differential pressure suppression term.

5. The method for suppressing fault pressure difference in a doubly-fed wind turbine as described in any one of claims 1-4, characterized in that, The method further includes transmitting the control voltage setpoint to the rotor converter to adjust the control voltage output value of the rotor converter. If a voltage drop is detected in the doubly fed fan, the doubly fed fan is connected to the unloading circuit, which is used to reduce the rotor current of the doubly fed fan.

6. A control device, characterized in that, include: A processor and a memory, the memory for storing a computer program, the processor for calling and running the computer program stored in the memory to implement the doubly fed fan fault differential pressure suppression method as described in any one of claims 1 to 4.

7. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the fault differential pressure suppression method for doubly fed wind turbines as described in any one of claims 1 to 4.

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