Self-synchronization regulation and control method and equipment for improving transient stability of doubly-fed fan

Abstract

The invention relates to a self-synchronizing regulation and control method and equipment for improving transient stability of a doubly-fed fan. The method comprises the following steps: obtaining equivalent circuits which enable stator and rotor sides of the doubly-fed fan to be equivalent to contain induced electromotive force respectively; based on an equivalent circuit, the induced electromotive force contained in the stator side is converted into a rotor dynamic compensation item in the grid-side converter, and the induced electromotive force contained in the rotor side is converted into a stator dynamic compensation item in the rotor-side converter; respectively constructing inner loop current control expressions of a rotor side converter and a grid side converter containing stator and rotor dynamic compensation items, and obtaining a vector current control model of an additional compensation item; and obtaining operation data of a rotor side converter and a grid side converter of the doubly-fed fan, and performing self-synchronization regulation and control on the double converters of the doubly-fed fan based on the operation data and the vector current control model of the additional compensation item, thereby realizing grid-connected stable operation and transient stable operation of the doubly-fed fan under the change of the power grid voltage.

Description

Technical Field

[0001] This application relates to the field of power grid technology, and in particular to a self-synchronization control method and device for improving the transient stability capability of doubly-fed wind turbines. Background Technology

[0002] Doubly fed induction generator (DFIG) wind turbines consist of mechanical and electrical subsystems. The stator is directly connected to the power grid, while the rotor is AC-excited through both grid-side and stator-side converters. Wind power is transmitted to the grid via dual channels in both the stator and rotor. Traditional DFIG control methods employ current vector decoupling control of dual converters, requiring strong voltage support from the grid to stabilize the control current. Under fault conditions, the transient stability of DFIG operation is significantly limited due to the influence of the DFIG itself and the control circuitry, and may even result in grid disconnection. Achieving transient stability of DFIG operation under grid voltage fluctuations is a pressing issue that needs to be addressed. Summary of the Invention

[0003] Therefore, it is necessary to provide a self-synchronization control method, equipment, device, and storage medium that can improve the transient stability capability of doubly-fed induction generators (DFIGs) by enabling transient stable operation of DFIGs under grid voltage variations.

[0004] The first aspect of this application provides a self-synchronization control method for improving the transient stability capability of a doubly-fed wind turbine, comprising:

[0005] Obtain equivalent circuits that represent the stator and rotor sides of a doubly fed wind turbine as containing induced electromotive forces;

[0006] Based on the equivalent circuit, the induced electromotive force contained in the stator side is converted into the rotor dynamic compensation term in the grid-side converter, and the induced electromotive force contained in the rotor side is converted into the stator dynamic compensation term in the rotor-side converter. Thus, the inner loop current control expressions of the rotor-side and grid-side converters containing stator and rotor dynamic compensation terms are constructed respectively, and the vector current control model with additional compensation term is obtained.

[0007] The operating data of the rotor-side converter and grid-side converter of the doubly-fed induction generator (DFIG) are obtained. Based on the operating data and the vector current control model of the additional compensation term, the dual converters of the DFIG are self-synchronized and controlled.

[0008] In one embodiment, the vector current control model of the additional compensation term is a precise transient model of the doubly fed wind turbine, which is based on the virtual synchronous machine phase-locked loop detection grid voltage self-synchronization technology and combined with the upper-level reactive power dispatching command.

[0009] In one embodiment, in the vector current control model of the additional compensation term, the doubly-fed induction generator (DFIG) rotor-side converter adopts power outer loop control + vector current inner loop control of the additional compensation term, and the grid-side converter adopts DC voltage and reactive power outer loop control + vector current inner loop control of the additional compensation term; the upper-level reactive power dispatching command is executed to allocate reactive power values ​​to the DFIG rotor-side and grid-side converters to provide the reactive power required by the power grid.

[0010] In one embodiment, the equivalent circuit includes a stator-side synchronous machine equivalent circuit and a rotor-side synchronous machine equivalent circuit;

[0011] The expression for the stator voltage of a doubly-fed wind turbine is:

[0012]

[0013] The expression for the rotor voltage of a doubly-fed wind turbine is:

[0014]

[0015] Where j is the imaginary part, v s and v r These are the stator and rotor voltage vectors of the doubly fed wind turbine, respectively; i s and i r These are the stator and rotor current vectors, respectively; ψ s and ψ r These are the stator and rotor flux linkage vectors, respectively; R s and R r These are the stator and rotor resistances, respectively; L s L r and L m These are the stator and rotor self-inductance and the magnetizing inductance, respectively; ω slip ω is the generator slip angular frequency. slip =ω s -ω r ω s and ω r These are the grid angular frequency and the generator rotor angular frequency, respectively; L′ s and L′ r These are the stator and rotor transient inductances of the doubly-fed wind turbine. σ is the leakage flux coefficient.

[0016] In one embodiment, in the vector current control model of the additional compensation term, the complex vector expression of the rotor-side voltage of the doubly-fed wind turbine is:

[0017]

[0018] The complex vector expression for the grid-side voltage of a doubly-fed induction generator (DFIG) is:

[0019]

[0020] In one embodiment, stator voltage orientation is used, and the complex vector expression of the rotor-side voltage of the doubly-fed wind turbine is:

[0021]

[0022] The complex vector expression for the grid-side voltage of a doubly-fed induction generator (DFIG) is:

[0023]

[0024] Among them, K p1 and K i1 These are the proportional and integral coefficients of the rotor current controller, respectively; i rref and i r These are the reference and actual values ​​of the rotor current, respectively; K p2 and K i2 These are the proportional and integral coefficients of the grid-side current controller, respectively; i sref and i s These are the reference and actual values ​​of the grid-side current, respectively.

[0025] In one embodiment, based on the operating data and the vector current control model of the additional compensation term, the dual converters of the doubly-fed wind turbine are self-synchronized and regulated, including:

[0026] Based on the operating data and the vector current control model of the additional compensation term, the complex vector of the rotor-side voltage and the complex vector of the grid-side voltage of the doubly-fed wind turbine are calculated.

[0027] Based on the complex vector of the rotor-side voltage of the doubly fed wind turbine, a rotor-side converter drive signal is generated and sent to the rotor-side converter of the doubly fed wind turbine.

[0028] Based on the complex vector of the grid-side voltage of the doubly fed wind turbine, a grid-side converter drive signal is generated and sent to the grid-side converter of the doubly fed wind turbine.

[0029] A second aspect of this application provides a self-synchronizing control device for improving the transient stability capability of a doubly-fed induction generator (DFIG), comprising a data acquisition board and a controller. The data acquisition board is connected to the rotor-side converter and the grid-side converter of the DFIG and sends acquired data to the controller. The controller is connected to the dual converters of the DFIG and is used to perform self-synchronizing control of the dual converters of the DFIG according to the above-described method.

[0030] A third aspect of this application provides a self-synchronizing control device for improving the transient stability capability of a doubly-fed wind turbine, comprising:

[0031] The model generation module is used to obtain equivalent circuits that represent the stator and rotor sides of the doubly fed wind turbine as containing induced electromotive force. Based on the equivalent circuits, the induced electromotive force contained in the stator side is converted into the rotor dynamic compensation term in the grid-side converter, and the induced electromotive force contained in the rotor side is converted into the stator dynamic compensation term in the rotor-side converter. Thus, the inner loop current control expressions of the rotor-side and grid-side converters containing stator and rotor dynamic compensation terms are constructed respectively, and the vector current control model with additional compensation term is obtained.

[0032] The self-synchronization control module is used to acquire the operating data of the rotor-side converter and grid-side converter of the doubly-fed wind turbine, and to perform self-synchronization control on the dual converters of the doubly-fed wind turbine based on the operating data and the vector current control model of the additional compensation term.

[0033] A fourth aspect of this application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-described method.

[0034] The aforementioned self-synchronization control method, equipment, device, and storage medium for improving the transient stability capability of doubly-fed induction generator (DFIG) wind turbines are based on equating the stator and rotor sides of the DFIG to equivalent circuits containing induced electromotive force (EMF). The induced EMF on the stator side is converted into a rotor dynamic compensation term in the grid-side converter, and the induced EMF on the rotor side is converted into a stator dynamic compensation term in the rotor-side converter. This allows for the construction of inner-loop current control expressions for the rotor-side and grid-side converters, respectively, containing stator and rotor dynamic compensation terms, resulting in a vector current control model with additional compensation terms. Then, the operating data of the rotor-side converter and grid-side converter of the DFIG are acquired. Based on the operating data and the vector current control model with additional compensation terms, self-synchronization control is performed on the dual converters of the DFIG, achieving stable grid-connected operation and transient stability of the DFIG under grid voltage variations. Attached Figure Description

[0035] Figure 1 This is a flowchart of a self-synchronization control method for improving the transient stability capability of a doubly-fed wind turbine in one embodiment;

[0036] Figure 2 This is a structural diagram of a doubly fed wind turbine system, a control scheme, and an equivalent circuit diagram of the stator and rotor sides in one embodiment;

[0037] Figure 3 This is a control block diagram of a grid-side converter containing rotor dynamic compensation terms in one embodiment;

[0038] Figure 4 This is a control block diagram of a rotor-side converter containing stator dynamic compensation terms in one embodiment;

[0039] Figure 5Here is a block diagram of a phase-locked loop control based on a virtual synchronous machine in one embodiment;

[0040] Figure 6 This is a structural block diagram of a self-synchronization control device for improving the transient stability capability of a doubly-fed wind turbine in one embodiment.

[0041] Figure 7 This is an internal structural diagram of a computer device in one embodiment. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0043] Traditional current vector decoupling control for doubly-fed induction generators (DFIGs) achieves good results under ideal grid conditions, but it struggles to adapt to medium- and long-term stable operation and grid-connected control under varying grid voltage. Therefore, achieving operation control for DFIGs that adapts to grid voltage fluctuations is crucial for their stable grid-connected operation. Currently, DFIG grid-connected operation faces the following problems: 1. The dual-converter current vector decoupling control of DFIGs requires strong voltage support from the grid to stabilize the control current. However, the grid does not provide sufficient voltage support for DFIGs, leading to grid-connected stability issues, particularly under weak grid conditions; 2. With high-proportion, high-penetration wind power grid connections, the low inertia and weak characteristics of the grid connection point are becoming apparent. The interaction between the DFIG's phase-locked loop and the grid impedance coupling causes increasingly significant grid-connected stability problems; 3. Under fault conditions, the transient stability capability is significantly limited due to the influence of the DFIG itself and its control components, even leading to grid disconnection.

[0044] Because the rotor-side and grid-side converters of doubly-fed induction generators (DFIGs) with excitation functions have small capacities, their overall control capability is relatively weak, making the operation and control strategy of DFIGs somewhat important. Under an ideal grid, the grid voltage amplitude, frequency, and phase angle are constant. The traditional vector current decoupling control method based on stator voltage orientation can achieve independent control of active and reactive power, providing a certain degree of anti-interference capability and achieving some results. The stator of the DFIG is directly connected to the grid, and the amplitude, frequency, and phase of the rotor current are controlled through the rotor-side converter, indirectly adjusting the output power on the stator side. The structure of the DFIG cannot effectively isolate the intrinsic connection between the DFIG and the grid, making it more sensitive to grid voltage fluctuations, especially grid faults. The small-capacity rotor-side converter limits the overall control capability of the DFIG, resulting in weak grid fault ride-through capability and transient stability. Traditional current PI controllers designed under ideal grid conditions can only effectively control DC quantities without steady-state error. They cannot achieve the desired control effect on AC quantities of double-frequency harmonics, leading to an imbalance in the stator and rotor current amplitudes of the doubly-fed induction generator (DFIG). In severe cases, this can jeopardize the stability of the power system and the grid-connected stable operation of the DFIG. In summary, as the problems of power system harmonics, reactive power, and the capacitive and inductive characteristics of transmission line impedance parameters become increasingly serious, grid voltage fluctuations occur. Under these non-ideal grid voltage conditions, problems arise in the operation control and transient stability of DFIGs. As a result, the traditional vector current decoupling control of existing DFIGs is ill-suited for grid-connected stability issues under grid voltage fluctuations.

[0045] Based on this, the self-synchronization control method for improving the transient stability of doubly-fed induction generator (DFIG) wind turbines provided in this application equates the stator and rotor sides of the DFIG wind turbine to equivalent circuits similar to synchronous machines containing induced electromotive force, based on the principle of dynamic system similarity, thus providing ideas for a new control strategy for DFIG wind turbines. It constructs inner-loop current control expressions for the rotor-side and grid-side converters containing stator and rotor dynamic compensation terms, referred to as vector current control models with additional compensation terms, to enhance the applicability of DFIG wind turbines to grid conditions. Based on operating data and the vector current control model with additional compensation terms, it performs self-synchronization control on the dual converters of the DFIG wind turbine to solve the problem that existing DFIG wind turbines using traditional vector current decoupling control methods are difficult to achieve stable grid-connected operation and transient stability under grid voltage changes.

[0046] In one embodiment, such as Figure 1 As shown, a self-synchronization control method for improving the transient stability capability of a doubly-fed induction generator (DFIG) wind turbine is provided, including:

[0047] Step S110: Obtain equivalent circuits for the stator and rotor sides of the doubly-fed induction generator (DFIG) wind turbine, respectively, containing induced electromotive force. Specifically, based on the structural characteristics of the DFIG wind turbine and the principle of dynamic system similarity, the stator and rotor sides can be pre-equivalently represented as equivalent circuits similar to synchronous machines, containing induced electromotive force. Electrically, the DFIG wind turbine is equivalent to a voltage source; electromechanically, it resembles a synchronous generator, exhibiting strong grid-connected stable operation and transient reactive power support capabilities under weak grid conditions.

[0048] Specifically, the equivalent circuit includes the stator-side synchronous machine equivalent circuit and the rotor-side synchronous machine equivalent circuit. Figure 2 The paper shows that the stator and rotor sides of a doubly fed fan are equivalent circuits similar to synchronous machines, each containing induced electromotive force, providing theoretical ideas for a new control strategy for doubly fed fans.

[0049] The expression for the stator voltage of a doubly-fed wind turbine is:

[0050]

[0051] As can be seen from the above equation, the stator voltage vector of a doubly-fed wind turbine is determined by the induced electromotive force e on the stator side. s The voltage drop across the stator resistance and transient inductance caused by the stator current. Composition, e s The value is directly related to the rotor flux linkage.

[0052] The expression for the rotor voltage of a doubly-fed wind turbine is:

[0053]

[0054] The above equation reflects the relationship between the rotor voltage and current of a doubly-fed induction generator (DFIG). The rotor voltage vector of the DFIG is determined by the induced electromotive force e on the rotor side. r The voltage drop across the rotor resistance and transient inductance caused by the rotor current. Composition, e r The value is directly related to the stator flux linkage.

[0055] In the above formula, j is the imaginary part, and v s and v r These are the stator and rotor voltage vectors of the doubly fed wind turbine, respectively; i s and i r These are the stator and rotor current vectors, respectively; ψ s and ψ r These are the stator and rotor flux linkage vectors, respectively; R s and R r These are the stator and rotor resistances, respectively; L s L r and L m These are the stator and rotor self-inductance and the magnetizing inductance, respectively; ωslip ω is the generator slip angular frequency. slip =ω s -ω r ω s and ω r These are the grid angular frequency and the generator rotor angular frequency, respectively; L s ′ and L r ′ are the stator and rotor transient inductances of the doubly-fed wind turbine, respectively. σ is the leakage flux coefficient.

[0056] Step S120: Based on the equivalent circuit, the induced electromotive force on the stator side is converted into a rotor dynamic compensation term in the grid-side converter, and the induced electromotive force on the rotor side is converted into a stator dynamic compensation term in the rotor-side converter. This allows for the construction of inner-loop current control expressions for the rotor-side and grid-side converters, respectively, containing stator and rotor dynamic compensation terms, thus obtaining a vector current control model with additional compensation terms. This vector current control model with additional compensation terms can be stored in the controller for self-synchronization control of the dual converters, in conjunction with the operating data collected from the rotor-side and grid-side converters.

[0057] Based on the equivalent circuits of the stator-side synchronous machine and the rotor-side synchronous machine, the induced electromotive force on the stator side is converted into the rotor dynamic compensation term in the grid-side converter, and the induced electromotive force on the rotor side is converted into the stator dynamic compensation term in the rotor-side converter. Thus, the inner loop current control expressions of the rotor-side and grid-side converters containing stator and rotor dynamic compensation terms are constructed respectively. This is referred to as the vector current control model with additional compensation terms, which can be used to adapt to the operation control of doubly-fed wind turbines under grid voltage changes and enhance the applicability of doubly-fed wind turbines to grid conditions.

[0058] The rotor current of a doubly fed wind turbine is induced by the electromotive force e on the rotor side. r (Stator flux linkage ψ) s ) and rotor voltage v under rotor-side converter control r The result is determined by the combined effect, and the rotor-side induced electromotive force e r It is obtained by the stator flux linkage of the doubly fed wind turbine generator induced on the rotor side. Its value changes mainly depend on the grid voltage, and is less affected by changes in rotor operating conditions.

[0059] The specific structure of the vector current control model for the additional compensation term is not unique. In one embodiment, the vector current control model for the additional compensation term is a precise transient model of the doubly-fed induction generator (DFIG) wind turbine established by combining a virtual synchronous machine phase-locked loop (PLL) detection technology for grid voltage self-synchronization with upper-level reactive power dispatch commands under grid voltage variations. Specifically, the rotor-side converter of the DFIG wind turbine adopts an outer power loop control + an inner vector current loop control for the additional compensation term, as shown below. Figure 3As shown; the grid-side converter adopts DC voltage and reactive power outer loop control + vector current inner loop control with additional compensation terms, such as... Figure 4 As shown. Figure 5 The diagram shows a control block diagram based on a virtual synchronous machine phase-locked loop. By executing upper-level reactive power scheduling commands, reactive power values ​​are allocated to the rotor side and grid side converters of the doubly-fed induction generator (DFIG) to provide the reactive power required by the power grid and reduce the impact of grid voltage drops on the DFIG.

[0060] Specifically, in the vector current control model with additional compensation terms, the complex vector expression for the rotor-side voltage of the doubly-fed wind turbine is:

[0061]

[0062] The above formula is the basis for improving the rotor-side converter control scheme design. Compared with the traditional control scheme, it is necessary to take into account the compensation term for the change of stator excitation current of the doubly fed wind turbine to establish an accurate transient model of the rotor-side converter, thereby improving the adaptability of the doubly fed wind turbine to grid faults.

[0063] If stator voltage orientation is used, then v sd =V s v sq =0, v s =V s The above formula can be written as

[0064]

[0065] Among them, V s This refers to the stator-side phase voltage amplitude of the doubly-fed induction generator (DFIG); v sd v sq These are the d- and shaft components of the stator-side voltage of the doubly-fed wind turbine, respectively; K p1 and K i1 These are the proportional and integral coefficients of the rotor current controller, respectively; i rref and i r These are the reference and actual values ​​of the rotor current, respectively. Based on the above formula, an accurate transient model of the rotor-side converter containing stator dynamic compensation terms can be established.

[0066] Furthermore, the grid-side converter voltage is v g , let v g =v s The complex vector expression for the grid-side voltage of a doubly-fed induction generator (DFIG) is:

[0067]

[0068] If stator voltage orientation is used, then v gd =V s v gq =0, v g =Vg The above formula can be written as

[0069]

[0070] Among them, V s and V g The phase voltage amplitudes on the stator side and grid side of the doubly-fed induction generator (DFIG); v gd v gq These are the d-axis and axis components of the grid-side voltage, respectively; K p2 and K i2 These are the proportional and integral coefficients of the grid-side current controller, respectively; i sref and i s These are the reference and actual values ​​of the grid-side current, respectively.

[0071] Step S130: Acquire the operating data of the rotor-side converter and grid-side converter of the doubly-fed induction generator (DFIG). Based on the operating data and the vector current control model with additional compensation terms, perform self-synchronization control on the dual converters of the DFIG. The quantity and type of operating data are not unique and are determined according to the data required by the vector current control model with additional compensation terms. Connect the rotor-side converter and grid-side converter of the DFIG to the data acquisition board and send the acquired operating data to the controller. The controller performs self-synchronization control on the dual converters of the DFIG based on the acquired operating data.

[0072] In one embodiment, step S130 includes: calculating the complex vector of the rotor-side voltage and the complex vector of the grid-side voltage of the doubly-fed induction generator (DFIG) based on the operating data and the vector current control model with additional compensation terms; generating a rotor-side converter drive signal based on the complex vector of the rotor-side voltage and sending it to the rotor-side converter of the DFIG; and generating a grid-side converter drive signal based on the complex vector of the grid-side voltage and sending it to the grid-side converter of the DFIG.

[0073] Specifically, the controller can also pre-store the correspondence between the rotor-side voltage complex vector and the amplitude of the rotor-side converter drive signal, as well as the correspondence between the grid-side voltage complex vector and the amplitude of the grid-side converter drive signal. For example... Figure 2 As shown, the controller substitutes the collected operating data into the vector current control model with additional compensation terms to obtain the complex vector of the rotor-side voltage and the complex vector of the grid-side voltage of the doubly-fed induction generator (DFIG). Then, by combining the saved correspondence, the corresponding rotor-side converter drive signal can be generated and sent to the rotor-side converter of the DFIG, and the corresponding grid-side converter drive signal can be generated and sent to the grid-side converter of the DFIG, thereby realizing self-synchronous control to improve the transient stability capability of the DFIG.

[0074] In one embodiment, a self-synchronizing control device for improving the transient stability capability of a doubly-fed induction generator (DFIG) wind turbine is provided, comprising a data acquisition board and a controller. The data acquisition board is connected to the rotor-side converter and the grid-side converter of the DFIG wind turbine and sends acquired data to the controller. The controller is connected to the two converters (i.e., the rotor-side converter and the grid-side converter) of the DFIG wind turbine and is used to perform self-synchronizing control of the two converters of the DFIG wind turbine according to the method described above. The controller can be, but is not limited to, various personal computers, laptops, smartphones, tablets, and portable wearable devices, such as smartwatches, smart bracelets, and head-mounted devices.

[0075] Based on the same inventive concept, this application also provides a self-synchronizing control device for improving the transient stability of a doubly-fed induction generator (DFIG) to implement the self-synchronizing control method for improving the transient stability of DFIGs described above. The solution provided by this device is similar to the solution described in the above method. Therefore, the specific limitations of one or more embodiments of the self-synchronizing control device for improving the transient stability of DFIGs provided below can be found in the limitations of the self-synchronizing control method for improving the transient stability of DFIGs described above, and will not be repeated here.

[0076] In one embodiment, such as Figure 6 As shown, a self-synchronizing control device for improving the transient stability capability of a doubly-fed induction generator (DFIG) is also provided, comprising: a model generation module 110 and a self-synchronizing control module 120, wherein:

[0077] The model generation module 110 is used to obtain equivalent circuits that represent the stator and rotor sides of the doubly fed wind turbine as containing induced electromotive force. Based on the equivalent circuits, the induced electromotive force contained in the stator side is converted into the rotor dynamic compensation term in the grid-side converter, and the induced electromotive force contained in the rotor side is converted into the stator dynamic compensation term in the rotor-side converter. Thus, the inner loop current control expressions of the rotor-side and grid-side converters containing stator and rotor dynamic compensation terms are constructed respectively, and the vector current control model with additional compensation terms is obtained.

[0078] The self-synchronization control module 120 is used to acquire the operating data of the rotor-side converter and grid-side converter of the doubly fed wind turbine, and to perform self-synchronization control on the dual converters of the doubly fed wind turbine based on the operating data and the vector current control model of the additional compensation term.

[0079] In one embodiment, the self-synchronization control module 120 calculates the complex vector of the rotor-side voltage and the complex vector of the grid-side voltage of the doubly-fed induction generator (DFIG) based on the operating data and the vector current control model of the additional compensation term; generates a rotor-side converter drive signal based on the complex vector of the rotor-side voltage and sends it to the rotor-side converter of the DFIG; and generates a grid-side converter drive signal based on the complex vector of the grid-side voltage and sends it to the grid-side converter of the DFIG.

[0080] The modules in the aforementioned self-synchronization control device for improving the transient stability of doubly-fed wind turbines can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the memory of a computer device as software, so that the processor can call and execute the corresponding operations of each module.

[0081] In one embodiment, a computer device is provided, which may be a terminal, and its internal structure diagram may be as follows: Figure 7 As shown, the computer device includes a processor, memory, input / output interface, communication interface, display unit, and input device. The processor, memory, and input / output interface are connected via a system bus, and the communication interface, display unit, and input device are also connected to the system bus via the input / output interface. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage media. The input / output interface is used for exchanging information between the processor and external devices. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, mobile cellular networks, NFC (Near Field Communication), or other technologies. When executed by the processor, the computer program implements a self-synchronizing control method to improve the transient stability of a doubly-fed wind turbine. The display unit is used to form a visually visible image and can be a display screen, projection device, or virtual reality imaging device. The display screen can be an LCD screen or an e-ink screen. The input device of the computer device can be a touch layer covering the display screen, or buttons, trackballs, or touchpads set on the casing of the computer device, or external keyboards, touchpads, or mice, etc.

[0082] Those skilled in the art will understand that Figure 7 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0083] In one embodiment, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of the method described above.

[0084] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-described method.

[0085] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps of the method described above.

[0086] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0087] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0088] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A self-synchronization control method for improving the transient stability capability of a doubly-fed induction generator (DFIG), characterized in that, include: Obtain equivalent circuits that represent the stator and rotor sides of a doubly fed wind turbine as containing induced electromotive forces; Based on the equivalent circuit, the induced electromotive force contained in the stator side is converted into the rotor dynamic compensation term in the grid-side converter, and the induced electromotive force contained in the rotor side is converted into the stator dynamic compensation term in the rotor-side converter. Thus, the inner loop current control expressions of the rotor-side and grid-side converters containing stator and rotor dynamic compensation terms are constructed respectively, and the vector current control model with additional compensation term is obtained. The operating data of the rotor-side converter and grid-side converter of the doubly-fed induction generator (DFIG) are obtained. Based on the operating data and the vector current control model of the additional compensation term, the dual converters of the DFIG are self-synchronized and controlled.

2. The method according to claim 1, characterized in that, The vector current control model for the additional compensation term is a precise transient model of the doubly-fed wind turbine, established by combining the virtual synchronous machine phase-locked loop detection grid voltage self-synchronization technology with upper-level reactive power dispatching commands.

3. The method according to claim 2, characterized in that, In the vector current control model of the additional compensation term, the rotor-side converter of the doubly-fed induction generator adopts power outer loop control + vector current inner loop control of the additional compensation term, and the grid-side converter adopts DC voltage and reactive power outer loop control + vector current inner loop control of the additional compensation term; the upper-level reactive power dispatching command is executed to allocate reactive power values ​​to the rotor-side and grid-side converters of the doubly-fed induction generator to provide the reactive power required by the power grid.

4. The method according to claim 3, characterized in that, The equivalent circuit includes a stator-side synchronous machine equivalent circuit and a rotor-side synchronous machine equivalent circuit; The expression for the stator voltage of a doubly-fed wind turbine is: The expression for the rotor voltage of a doubly-fed wind turbine is: Where j is the imaginary part, v s and v r These are the stator and rotor voltage vectors of the doubly fed wind turbine, respectively; i s and i r These are the stator and rotor current vectors, respectively; ψ s and ψ r These are the stator and rotor flux linkage vectors, respectively; R s and R r These are the stator and rotor resistances, respectively; L s L r and L m These are the stator and rotor self-inductance and the magnetizing inductance, respectively; ω slip ω is the generator slip angular frequency. slip =ω s -ω r ω s and ω r These are the grid angular frequency and the generator rotor angular frequency, respectively; L s ′ and L r ′ represents the stator and rotor transient inductances of the doubly-fed wind turbine, respectively. σ is the leakage flux coefficient.

5. The method according to claim 4, characterized in that, In the vector current control model of the additional compensation term, the complex vector expression of the rotor-side voltage of the doubly-fed wind turbine is: The complex vector expression for the grid-side voltage of a doubly-fed induction generator (DFIG) is:

6. The method according to claim 5, characterized in that, Using stator voltage orientation, the complex vector expression of the rotor-side voltage of the doubly-fed wind turbine is: The complex vector expression for the grid-side voltage of a doubly-fed induction generator (DFIG) is: Among them, K p1 and K i1 These are the proportional and integral coefficients of the rotor current controller, respectively; i rref and i r These are the reference and actual values ​​of the rotor current, respectively; K p2 and K i2 These are the proportional and integral coefficients of the grid-side current controller, respectively; i sref and i s These are the reference and actual values ​​of the grid-side current, respectively.

7. The method according to any one of claims 1 to 6, characterized in that, Based on the aforementioned operating data and the vector current control model of the additional compensation term, self-synchronization control is performed on the dual converters of the doubly-fed wind turbine, including: Based on the operating data and the vector current control model of the additional compensation term, the complex vector of the rotor-side voltage and the complex vector of the grid-side voltage of the doubly-fed wind turbine are calculated. Based on the complex vector of the rotor-side voltage of the doubly fed wind turbine, a rotor-side converter drive signal is generated and sent to the rotor-side converter of the doubly fed wind turbine. Based on the complex vector of the grid-side voltage of the doubly fed wind turbine, a grid-side converter drive signal is generated and sent to the grid-side converter of the doubly fed wind turbine.

8. A self-synchronizing control device for improving the transient stability capability of a doubly-fed wind turbine, characterized in that, The system includes a data acquisition board and a controller. The data acquisition board is connected to the rotor-side converter and the grid-side converter of the doubly-fed wind turbine and sends acquired data to the controller. The controller is connected to the dual converters of the doubly-fed wind turbine and is used to perform self-synchronization control of the dual converters of the doubly-fed wind turbine according to the method described in any one of claims 1 to 7.

9. A self-synchronizing control device for improving the transient stability capability of a doubly-fed wind turbine, characterized in that, include: The model generation module is used to obtain equivalent circuits that represent the stator and rotor sides of the doubly fed wind turbine as containing induced electromotive forces. Based on the equivalent circuit, the induced electromotive force contained in the stator side is converted into the rotor dynamic compensation term in the grid-side converter, and the induced electromotive force contained in the rotor side is converted into the stator dynamic compensation term in the rotor-side converter. Thus, the inner loop current control expressions of the rotor-side and grid-side converters containing stator and rotor dynamic compensation terms are constructed respectively, and the vector current control model with additional compensation term is obtained. The self-synchronization control module is used to acquire the operating data of the rotor-side converter and grid-side converter of the doubly-fed wind turbine, and to perform self-synchronization control on the dual converters of the doubly-fed wind turbine based on the operating data and the vector current control model of the additional compensation term.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 7.

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