A method and device for suppressing subsynchronous resonance in a wind-fire bundled transmission system with series compensation

Abstract

This invention provides a method and apparatus for suppressing subsynchronous resonance in a wind-fire bundled power transmission system with series compensation. The method includes: dq decoupling control based on stator dynamic flux compensation; superimposing the stator current of the doubly-fed induction generator (DFIG) onto the rotor reference voltage of the turbine-side converter via a transfer function; and optimizing the phase angle and amplitude characteristics of the transfer function within the subsynchronous frequency band to achieve overall optimization of the damping characteristics of the DFIG in the subsynchronous frequency band. This application achieves suppression of subsynchronous resonance in the wind-fire bundled power transmission system by comprehensively reshaping the impedance characteristics of the DFIG in the subsynchronous frequency band and optimizing its damping characteristics.

Description

Technical Field

[0001] This application belongs to the field of wind power generation technology, specifically, it relates to a method and device for suppressing subsynchronous resonance in a wind-fire bundled transmission system with series compensation. Background Technology

[0002] When wind power production bases are far from load centers and require long-distance inter-regional power transmission, a bundled wind-thermal power transmission method with series compensation is used. This involves transmitting both thermal and wind power through AC transmission lines with series compensation. This approach leverages the adjustability of thermal power to mitigate the fluctuations and randomness of wind power output, while also enhancing the transmission capacity of AC transmission channels using the series-compensated AC lines. However, with the integration of wind power, the subsynchronous interactions between wind, thermal, and series-compensated systems become more complex, increasing the risk of torsional vibration in the shaft system of thermal power units and subsynchronous electrical resonance in the power grid. Traditional methods for analyzing and optimizing the subsynchronous resonance mechanism of wind turbine units based on the Nyquist criterion are highly dependent on the structure and parameters of the power grid system and can only perform stability assessments and optimizations for specific frequency bands or points, making it difficult to optimize the impedance characteristics of wind turbine units across the entire subsynchronous frequency band. Summary of the Invention

[0003] This application provides a method and apparatus for suppressing subsynchronous resonance in a wind-thermal power bundled transmission system via series compensation, in order to solve the problem that when large-scale wind power bases are connected, the subsynchronous interaction between wind power, thermal power and series compensation systems becomes more complex, increasing the risk of torsional vibration of the shaft system of thermal power units and subsynchronous electrical resonance in the power grid.

[0004] According to the first aspect of this application, a method for suppressing subsynchronous resonance in a wind-fire bundled transmission system with series compensation is provided, comprising:

[0005] Obtain the positive sequence impedance at the terminals of the doubly-fed wind turbine;

[0006] The stator current of the doubly fed wind turbine is superimposed onto the rotor reference voltage of the machine-side converter via a transfer function;

[0007] The damping characteristics of the doubly fed wind turbine terminal impedance in the subsynchronous frequency band are adjusted by tuning the transfer function.

[0008] In one embodiment, the stator current of the doubly-fed wind turbine in the wind-fire bundled transmission system is superimposed onto the rotor reference voltage of the turbine-side converter via a transfer function, including:

[0009] The stator current of the doubly fed wind turbine in the synchronous rotating coordinate system is expressed as the d-axis and q-axis components i. sd and i sq The rotor reference voltage d-axis and q-axis components U, fed back through the transfer function R(s), are superimposed onto the machine-side converter. rd_ref and U rq_refsuperior.

[0010] In one embodiment, the method for suppressing subsynchronous resonance in a wind-fire bundled transmission system further includes:

[0011] By adjusting the control parameters of the transfer function R(s), the phase of the transfer function H'(s) in the subsynchronous frequency band is kept between [-90°, 0°].

[0012] The subsynchronous stability of the wind-fire bundled power transmission system is improved by optimizing the damping characteristics of the doubly fed wind turbine in the subsynchronous frequency band through the transfer function R(s).

[0013] In one embodiment, obtaining the positive sequence impedance of the doubly-fed wind turbine terminals includes:

[0014] DQ decoupling control is achieved by using dq decoupling and stator flux dynamic compensation in the inner loop of the machine-side converter.

[0015] After achieving dq decoupling control, the dq impedance matrix in the synchronous rotating coordinate system is transformed into the positive and negative sequence impedance matrix in the stationary coordinate system to obtain the positive sequence impedance at the doubly fed wind turbine terminal.

[0016] In one embodiment, adjusting the damping characteristics of the doubly-fed induction generator (DFIG) terminal impedance in the subsynchronous frequency band by tuning the transfer function includes:

[0017] A new wind turbine terminal impedance characteristic is obtained by introducing additional damping control based on stator current feedback in the machine-side converter.

[0018] Based on the new turbine terminal impedance characteristics, the control parameters of the transfer function R(s) are tuned to optimize the damping level of the doubly fed wind turbine in the subsynchronous frequency band.

[0019] According to another aspect of this application, a subsynchronous resonance suppression device for a wind-fire bundled transmission system with series compensation is also provided, comprising:

[0020] The superposition unit is used to superimpose the stator current of the wind-fire bundled transmission system onto the reference voltage of the rotor-side converter.

[0021] Positive sequence impedance acquisition unit, used to acquire the positive sequence impedance of the stator port of the doubly fed wind turbine;

[0022] The damping characteristic modification unit adjusts the control parameters of the transfer function R(s) to optimize the damping characteristics of the doubly fed wind turbine in the subsynchronous frequency band.

[0023] In one embodiment, the stacking unit includes:

[0024] The component superposition module is used to superimpose the stator current components i along the d-axis and q-axis in the synchronous rotating coordinate system. sd and i sqThe rotor reference voltage d-axis and q-axis components U, fed back through the transfer function R(s), are superimposed onto the machine-side converter. rd_ref and U rq_ref superior.

[0025] In one embodiment, the subsynchronous resonance suppression device of the wind-fire bundled transmission system further includes:

[0026] The tuning module is used to tune the control parameters of the transfer function R(s) so that the phase of the transfer function H'(s) in the subsynchronous frequency band is between [-90°, 0°].

[0027] The stability enhancement module is used to improve the subsynchronous stability of the wind-fire bundled power transmission system by optimizing the damping characteristics of the doubly fed wind turbine in the subsynchronous frequency band through the transfer function R(s).

[0028] In one embodiment, the positive-sequence impedance acquisition unit includes:

[0029] The decoupling module is used to achieve dq decoupling control in the inner loop of the machine-side converter by using dq decoupling and stator flux dynamic compensation.

[0030] The matrix transformation module is used to transform the dq impedance matrix in the synchronous rotating coordinate system to the positive and negative sequence impedance matrix in the stationary coordinate system after dq decoupling control to obtain the positive sequence impedance of the stator port of the doubly fed wind turbine.

[0031] In one embodiment, the damping characteristic changing unit includes:

[0032] The new impedance characteristic acquisition module is used to obtain new stator port impedance characteristics by introducing additional damping control of the machine-side converter based on stator current feedback, on the basis of obtaining stator port impedance characteristics by positive sequence impedance.

[0033] The damping level changing module adjusts the control parameters of the transfer function R(s) to optimize the damping characteristics of the doubly fed wind turbine in the subsynchronous frequency band.

[0034] This application achieves suppression of the subsynchronous resonance phenomenon in the wind-fire bundled power transmission system by comprehensively reshaping the impedance characteristics of the subsynchronous frequency band of the doubly-fed wind turbine and optimizing the damping characteristics of the subsynchronous frequency band of the doubly-fed wind turbine. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1A block diagram of vector control for a doubly fed wind turbine machine-side converter considering dynamic compensation of stator flux is provided for this application.

[0037] Figure 2 This application provides an additional damping control method for a doubly fed wind turbine rotor-side converter that considers stator current feedback.

[0038] Figure 3 This application describes a method for suppressing subsynchronous resonance in a wind-fire bundled transmission system via series compensation.

[0039] Figure 4 This application describes a method for obtaining the positive sequence impedance of the stator port of a doubly fed wind turbine.

[0040] Figure 5 This is a flowchart illustrating the method for changing the damping characteristics of the original doubly fed wind turbine terminal impedance in the subsynchronous frequency band, as described in this application.

[0041] Figure 6 The block diagram of the additional damping control of the rotor-side converter of the doubly fed wind turbine based on stator current feedback is provided in this application.

[0042] Figure 7 This application provides a subsynchronous resonance suppression device for a wind-fire bundling and series-compensated external transmission system.

[0043] Figure 8 This is a subsynchronous resonance suppression device for a wind-fire bundling and series-compensated external transmission system in another embodiment of this application.

[0044] Figure 9 This is a structural block diagram of the positive sequence impedance acquisition unit in an embodiment of this application.

[0045] Figure 10 This is a structural block diagram of the damping characteristic changing unit in the embodiments of this application.

[0046] Figure 11 This is a specific implementation of an electronic device in the embodiments of this application. Detailed Implementation

[0047] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] To address the subsynchronous resonance problem in wind-fire bundled power transmission systems, this application proposes a method for suppressing subsynchronous resonance in such systems based on additional damping control of the rotor-side converter, considering dynamic compensation of the stator flux linkage. By comprehensively reshaping the impedance characteristics of the subsynchronous frequency band of the doubly-fed wind turbine and optimizing its damping characteristics, the subsynchronous resonance phenomenon in the wind-fire bundled power transmission system can be suppressed.

[0049] Specifically, a doubly-fed induction generator (DFIG) wind turbine mainly consists of a wind turbine generator, an induction generator, a grid-side converter, a machine-side converter, a main control unit, a converter controller, and a box-type transformer. The DFIG wind turbine uses two back-to-back power electronic converters connected via a DC link for AC excitation, achieving variable-speed constant-frequency operation and maximum energy tracking control. The grid-side converter's operation control objective is primarily to stabilize the DC bus voltage, while the machine-side converter's operation control objective is primarily to control the active and reactive power output of the wind turbine. The machine-side converter uses vector control to control the rotor current of the induction generator. To ensure good dynamic performance of the DFIG wind turbine system under grid voltage fault conditions, an improved vector control scheme considering dynamic compensation of the stator flux is generally adopted, such as... Figure 1 As shown. Among them, and i rd and i rq These are the commanded and measured values ​​for the d-axis and q-axis components of the rotor current, respectively. and u rd2 and u rq2 These are the command values ​​for the d-axis and q-axis components of the rotor voltage, and the d-axis and q-axis components of the dynamic flux compensation components, respectively. sdq and I sdq U sαβ and I sαβ The dq-axis components and αβ components of the stator voltage and stator current, respectively, are ψ s and ψ sdq These are the flux linkage vector and its dq-axis components, R. r L r L m L s These are the rotor resistance, rotor inductance, magnetizing inductance, and stator inductance, respectively, ω slip Slip rate

[0050] This application proposes an additional damping control method for the rotor-side converter of a doubly-fed induction generator (DFIG) based on stator flux dynamic compensation, considering stator current feedback. Figure 2 As shown, it includes:

[0051] S201: Obtain the positive sequence impedance at the terminal of the doubly fed wind turbine;

[0052] S202: The stator current of the doubly fed wind turbine is superimposed onto the rotor reference voltage of the machine-side converter via a transfer function;

[0053] S203: Adjust the damping characteristics of the doubly fed wind turbine terminal impedance in the subsynchronous frequency band by setting the transfer function.

[0054] In one embodiment, the stator current of the doubly-fed induction generator is superimposed onto the rotor reference voltage of the turbine-side converter via a transfer function, including:

[0055] The stator current of the doubly fed wind turbine in the synchronous rotating coordinate system is expressed as the d-axis and q-axis components i. sd and i sq The feedback is fed back through the transfer function R(s) and then superimposed onto the d-axis and q-axis components U of the rotor reference voltage of the machine-side converter. rd_ref and U rq_ref superior.

[0056] In one embodiment, such as Figure 3 As shown, the method for suppressing subsynchronous resonance in a wind-fire bundled transmission system with series compensation also includes:

[0057] S301: By adjusting the control parameters of the transfer function R(s), the phase of the transfer function H(s) in the subsynchronous frequency band is kept between [-90°, 0°].

[0058] S302: The damping characteristics of the doubly fed wind turbine in the subsynchronous frequency band are optimized by optimizing the transfer function R(s), thereby improving the subsynchronous stability of the wind-fire bundled power transmission system.

[0059] In one embodiment, the positive sequence impedance of the doubly-fed wind turbine terminals is obtained, such as... Figure 4 As shown, it includes:

[0060] S401: DQ decoupling control is achieved by using dq decoupling and stator flux dynamic compensation in the inner loop of the machine-side converter.

[0061] S402: After realizing dq decoupling control, the dq impedance matrix in the synchronous rotating coordinate system is transformed into the positive and negative sequence impedance matrix in the stationary coordinate system to obtain the positive sequence impedance of the stator port of the doubly fed wind turbine.

[0062] In one embodiment, the damping characteristics of the doubly-fed induction generator (DFIG) terminal impedance in the subsynchronous frequency band are adjusted by tuning the transfer function, such as... Figure 5 As shown, it includes:

[0063] S501: After obtaining the stator port positive sequence impedance characteristics, a new stator port impedance characteristic is obtained by introducing additional damping control of the machine-side converter based on stator current feedback.

[0064] S502: Based on the new stator port impedance characteristics, the control parameters of the transfer function R(s) are tuned to change the damping level of the doubly fed wind turbine in the subsynchronous frequency band.

[0065] In one specific embodiment, such as Figure 6 As shown, based on the stator port impedance modeling of the doubly-fed induction generator (DFIG) wind turbine, the control structure design and control parameter tuning of the transfer function R(s) used for additional damping control are performed. This optimizes the overall damping level of the DFIG wind turbine in the sub-synchronous frequency band, thereby improving the overall oscillation stability of the wind-fired power transmission system in the sub-synchronous frequency band. Wherein, i sd and i sq These are the measured values ​​of the d-axis and q-axis components of the stator current of the doubly fed wind turbine, respectively. Furthermore, the tuning transfer function used in the process of tuning the control parameters can be of various types, and this application is not limited to this.

[0066] Considering the improved vector control that takes into account the dynamic compensation of stator flux linkage, an additional damping control method based on stator current feedback is used. The d-axis and q-axis components of the stator current in the synchronous rotating coordinate system are fed back through the transfer function R(s) and then superimposed onto the d-axis and q-axis components U of the rotor reference voltage of the machine-side converter in the synchronous rotating coordinate system. rd_ref and U rq_ref Above, such as Figure 3 As shown, this changes the damping characteristics of the original doubly fed wind turbine terminal impedance in the subsynchronous frequency band. One possible implementation of R(s) is expressed as shown in equation (1), which includes a DC blocking element, a low-pass filter, and an integration element.

[0067]

[0068] The derivation process is as follows.

[0069] To achieve dq decoupling control, the inner loop of the machine-side converter adopts dq decoupling and dynamic flux compensation, as shown in equation (2).

[0070]

[0071] Ignoring the rotor resistance and considering equation (3), equation (4) can be derived.

[0072]

[0073]

[0074] The default outer loop and phase-locked loop are relatively slow, as shown in equation (5).

[0075]

[0076] Transform the dq impedance matrix in the synchronous rotating coordinate system to the positive and negative sequence impedance matrix in the stationary coordinate system, and the positive and negative sequence impedances of the stator port of the doubly fed wind turbine can be obtained as shown in equation (6).

[0077]

[0078] make Taking the positive sequence impedance as an example, its phase expression is shown in equation (7). It can be seen that the phase of the transfer function H(s) determines the damping level of the doubly-fed wind turbine.

[0079]

[0080] After introducing additional damping control for the machine-side converter based on stator current feedback, such as Figure 3 As shown, the stator port impedance characteristics at this time are as shown in equation (8).

[0081]

[0082] make Therefore, by properly tuning the control parameters of R(s), the overall phase characteristics of the transfer function H'(s) in the sub-synchronous frequency band can be changed, thereby altering the damping level of the doubly-fed induction generator (DFIG) in the sub-synchronous frequency band. This tuning method is based solely on the DFIG terminal impedance model and does not include the grid structure and parameters, making it independent of the specific grid structure and parameters.

[0083] In addition, this application also proposes a possible implementation of R(s), as shown in equation (9). The derivation process is basically the same as before, so it will not be repeated here.

[0084]

[0085] In addition, this application also provides a method for tuning the additional damping control parameters of a doubly-fed induction generator (DFIG) based on stator current feedback. By properly tuning the control parameters of R(s), the phase of R'(s) in the subsynchronous frequency band is made to be between [-90°, 0°], thereby improving the positive damping characteristics of the doubly fed wind turbine in the subsynchronous frequency band and thus enhancing the subsynchronous stability of the wind-fire bundled power transmission system.

[0086] The derivation process of the R(s) control parameter tuning method is shown below:

[0087] As mentioned above, H(s) and H'(s) can be decomposed into the form shown in equation (9):

[0088]

[0089] Let the phase of H(s) be By introducing additional damping control R(s), the phase of R'(s) in the subsynchronous frequency band is made to be... This ensures that the phase of H'(s) in the subsynchronous frequency band satisfies [-90°, 0], which in turn ensures that the phase of the positive sequence impedance at the doubly-fed wind turbine terminal satisfies [0°, 90°], thereby optimizing the damping characteristics of the doubly-fed wind turbine in the subsynchronous frequency band.

[0090] In summary, compared with the prior art, this application considers the additional damping control method of the generator-side converter with dynamic compensation of stator flux linkage, thereby changing the overall damping characteristics of the original doubly-fed induction generator (DFIG) terminal impedance in the subsynchronous frequency band. In addition, this application also includes a method for tuning the additional damping control parameters of the DFIG based on stator current feedback, which optimizes the overall damping characteristics of the DFIG terminal impedance in the subsynchronous frequency band, thereby improving the subsynchronous stability of the wind-fire bundled power transmission system.

[0091] Based on the same inventive concept, this application also provides a subsynchronous resonance suppression device for a wind-fire bundled transmission system with series compensation, which can be used to implement the method described in the above embodiments, as described in the following embodiments. Since the principle of this wind-fire bundled transmission system with series compensation in solving the problem is similar to the method for suppressing subsynchronous resonance in a wind-fire bundled transmission system with series compensation, the implementation of the wind-fire bundled transmission system with series compensation can refer to the implementation of the method for suppressing subsynchronous resonance in a wind-fire bundled transmission system with series compensation, and repeated details will not be elaborated further. As used below, the terms "unit" or "module" can refer to a combination of software and / or hardware that performs a predetermined function. Although the system described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0092] According to another aspect of this application, a subsynchronous resonance suppression device for a wind-fire bundled transmission system with series compensation is also provided, such as... Figure 7 As shown, it includes:

[0093] The superposition unit 701 is used to superimpose the stator current of the doubly fed wind turbine onto the rotor reference voltage of the machine-side converter via a transfer function.

[0094] Positive sequence impedance acquisition unit 702 is used to acquire the positive sequence impedance of the doubly fed wind turbine terminal;

[0095] The damping characteristic changing unit 703 adjusts the damping characteristics of the doubly fed wind turbine terminal impedance in the subsynchronous frequency band by setting the transfer function.

[0096] In one embodiment, the overlay unit 701 includes:

[0097] The component superposition module is used to superimpose the stator current components i along the d-axis and q-axis in the synchronous rotating coordinate system. sd and isq The rotor reference voltage d-axis and q-axis components U, fed back through the transfer function R(s), are superimposed onto the machine-side converter. rd_ref and U rq_ref superior.

[0098] In one embodiment, such as Figure 8 As shown, the subsynchronous resonance suppression device of the wind-fire bundled transmission system also includes:

[0099] The tuning module 801 is used to tune the control parameters of the transfer function R(s) so that the phase of the transfer function H'(s) in the subsynchronous frequency band is between [-90°, 0°].

[0100] The stability enhancement module 802 is used to improve the subsynchronous stability of the wind-fire bundled power transmission system by optimizing the damping characteristics of the doubly fed wind turbine in the subsynchronous frequency band through the transfer function R(s).

[0101] In one embodiment, such as Figure 9 As shown, the positive and negative impedance acquisition unit 702 includes:

[0102] Decoupling module 901 is used to achieve dq decoupling control in the inner loop of the machine-side converter by using dq decoupling and flux compensation.

[0103] The matrix transformation module 902 is used to transform the dq impedance matrix in the synchronous rotating coordinate system to the positive and negative sequence impedance matrix in the stationary coordinate system after dq decoupling control to obtain the positive sequence impedance of the stator port of the doubly fed wind turbine.

[0104] In one embodiment, such as Figure 10 As shown, the damping characteristic changing unit 703 includes:

[0105] The new impedance characteristic acquisition module 1001 is used to obtain new stator port impedance characteristics by introducing additional damping control of the machine-side converter based on stator current feedback on the stator port impedance characteristics obtained by positive sequence impedance.

[0106] The damping level changing module 1002 is used to adjust the control parameters of the transfer function R(s) according to the new stator port impedance characteristics, thereby changing the damping level of the doubly fed wind turbine in the subsynchronous frequency band.

[0107] This application achieves suppression of the subsynchronous resonance phenomenon in the wind-fire bundled power transmission system by comprehensively reshaping the impedance characteristics of the subsynchronous frequency band of the doubly-fed wind turbine and optimizing the damping characteristics of the subsynchronous frequency band of the doubly-fed wind turbine.

[0108] This application also provides a specific implementation of an electronic device capable of implementing all the steps in the methods described above. See [link to implementation details]. Figure 11 The electronic device specifically includes the following:

[0109] Processor 1101, memory 1102, communications interface 1103, bus 1104, and non-volatile memory 1105;

[0110] The processor 1101, memory 1102, and communication interface 1103 communicate with each other through the bus 1104.

[0111] The processor 1101 is used to call a computer program in the memory 1102 and the non-volatile memory 1105. When the processor executes the computer program, it implements all the steps in the method in the above embodiments. For example, when the processor executes the computer program, it implements the following steps:

[0112] S201: The stator current of the doubly fed wind turbine is superimposed onto the rotor reference voltage of the turbine-side converter through a transfer function.

[0113] S202: Obtain the positive sequence impedance of the stator port of the doubly fed fan.

[0114] S203: By adjusting the transfer function, the damping characteristics of the doubly fed wind turbine terminal impedance in the subsynchronous frequency band can be changed.

[0115] Embodiments of this application also provide a computer-readable storage medium capable of implementing all steps of the methods in the above embodiments. The computer-readable storage medium stores a computer program that, when executed by a processor, implements all steps of the methods in the above embodiments. For example, when the processor executes the computer program, it implements the following steps:

[0116] S201: The stator current of the doubly fed wind turbine is superimposed onto the rotor reference voltage of the turbine-side converter through a transfer function.

[0117] S202: Obtain the positive sequence impedance of the stator port of the doubly fed fan.

[0118] S203: By adjusting the transfer function, the damping characteristics of the doubly fed wind turbine terminal impedance in the subsynchronous frequency band can be changed.

[0119] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on its differences from other embodiments. In particular, for hardware + program embodiments, since they are basically similar to method embodiments, the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. Although the embodiments in this specification provide the method operation steps as shown in the embodiments or flowcharts, more or fewer operation steps may be included based on conventional or non-inventive means. The order of steps listed in the embodiments is merely one possible execution order among many steps and does not represent the only execution order. In actual device or terminal product execution, the methods can be executed in the order shown in the embodiments or drawings or in parallel (e.g., in a parallel processor or multi-threaded processing environment, or even a distributed data processing environment). The terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, product, or apparatus that includes a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, product, or apparatus. Without further limitations, the presence of other identical or equivalent elements in the process, method, product, or apparatus that includes said elements is not excluded. For ease of description, the above devices are described in terms of function, divided into various modules. Of course, in implementing the embodiments of this specification, the functions of each module can be implemented in one or more software and / or hardware, or the module implementing the same function can be implemented by a combination of multiple sub-modules or sub-units, etc. The device embodiments described above are merely illustrative. For example, the division of units is only a logical functional division; 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. This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing device to produce a machine, such that the instructions, which are executable by the processor of the computer or other programmable data processing device, produce instructions for implementing the process. Figure 1 One or more processes and / or boxes Figure 1The apparatus is designed to perform the functions specified in one or more boxes. Those skilled in the art will understand that embodiments of this specification can be provided as methods, systems, or computer program products. Therefore, embodiments of this specification can take the form of entirely hardware embodiments, entirely software embodiments, or embodiments combining software and hardware aspects. Furthermore, embodiments of this specification can take the form of computer program products implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. The various embodiments in this specification are described in a progressive manner, with reference to each other for similar or identical parts. Each embodiment focuses on describing the differences from other embodiments. In particular, system embodiments are generally similar to method embodiments, so the description is relatively simple, and relevant parts can be referred to in the description of the method embodiments. In the description of this specification, references to terms such as "an embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example that are included in at least one embodiment or example of the embodiments of this specification. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples, without contradiction. The above descriptions are merely examples of embodiments of this specification and are not intended to limit the embodiments of this specification. Various modifications and variations can be made to the embodiments of this specification by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the embodiments of this specification should be included within the scope of the claims of the embodiments of this specification.

Claims

1. A method for suppressing subsynchronous resonance in a wind-fire bundled transmission system with series compensation, characterized in that, include: Obtain the positive sequence impedance at the terminals of the doubly-fed wind turbine; The stator current of the doubly fed wind turbine is superimposed onto the rotor reference voltage of the machine-side converter via a transfer function; The damping characteristics of the doubly fed wind turbine terminal impedance in the subsynchronous frequency band are adjusted by tuning the transfer function. The step of superimposing the stator current of the doubly-fed induction generator (DFIG) onto the rotor reference voltage of the turbine-side converter via a transfer function includes: merging the d-axis and q-axis components of the stator current in a synchronous rotating coordinate system. and By passing function R (s) The rotor reference voltage d-axis and q-axis components, after feedback, are superimposed onto the machine-side converter. U rd_ref and U rq_ref superior; By adjusting the control parameters of the transfer function R(s), the phase of the transfer function H'(s) in the subsynchronous frequency band is kept between [-90°, 0°]. The damping characteristics of the doubly fed wind turbine in the subsynchronous frequency band are optimized by optimizing the transfer function R(s), thereby improving the subsynchronous stability of the wind-fire bundled transmission system. The process of adjusting the control parameters of the transfer function R(s) to ensure that the phase of the transfer function H'(s) in the subsynchronous frequency band is between [-90°, 0°] includes: ； Among them, let ; Among them, L s L is the inductance of the stator winding. r L is the inductance of the rotor winding. m G is the magnetizing inductance between the stator winding and the rotor winding; i Indicates the current loop controller gain; Original transfer function The phase is In the original transfer function Introducing a transfer function R(s) to make the subsynchronous frequency band phase of the transfer function R'(s) in... Between, making The phase in the subsynchronous frequency band is between [-90°, 0°].

2. The method for suppressing subsynchronous resonance in a wind-fire bundled transmission system via series compensation as described in claim 1, characterized in that, The process of obtaining the positive sequence impedance at the terminals of the doubly fed wind turbine includes: In the inner loop of the machine-side converter, dq decoupling control is achieved by using dynamic compensation of stator flux linkage and dq decoupling. After achieving dq decoupling control, the dq impedance matrix in the synchronous rotating coordinate system is transformed into the positive and negative sequence impedance matrix in the stationary coordinate system to obtain the positive sequence impedance of the doubly fed wind turbine terminal.

3. The method for suppressing subsynchronous resonance in a wind-fire bundled transmission system via series compensation as described in claim 1, characterized in that, The method of adjusting the damping characteristics of the doubly fed wind turbine terminal impedance in the subsynchronous frequency band by setting the transfer function includes: By introducing additional damping control of the generator-side converter based on stator current feedback, a new terminal impedance characteristic of the doubly fed wind turbine is obtained. Based on the new terminal impedance characteristics, the control parameters of the transfer function R(s) are tuned, and the phase frequency and amplitude frequency characteristics of R(s) in the subsynchronous frequency band are adjusted, thereby optimizing the damping level of the doubly fed wind turbine in the subsynchronous frequency band.

4. A subsynchronous resonance suppression device for a wind-fire bundling and series-compensated external transmission system, characterized in that, include: The superposition unit is used to superimpose the stator current of the wind-fire bundled transmission system onto the reference voltage of the rotor-side converter; Positive sequence impedance acquisition unit, used to acquire the positive sequence impedance of the stator port of the doubly fed wind turbine; The damping characteristic changing unit is used to obtain the stator port impedance characteristics based on the positive sequence impedance, thereby changing the damping characteristics of the original doubly fed wind turbine terminal impedance in the subsynchronous frequency band. The superposition unit includes: The component superposition module is used to combine the d-axis and q-axis components of the stator current in a synchronous rotating coordinate system. and By passing function R (s) The rotor reference voltage d-axis and q-axis components, after feedback, are superimposed onto the machine-side converter. U rd_ref and U rq_ref superior; The device further includes: The tuning module is used to tune the control parameters of the transfer function R(s) so that the phase of the transfer function H'(s) in the subsynchronous frequency band is between [-90°, 0°]. The stability enhancement module is used to improve the damping characteristics of the doubly fed wind turbine in the subsynchronous frequency band by improving the transfer function R(s), thereby improving the subsynchronous stability of the wind-fire bundled power transmission system. in, ； in, ; Among them, L s L is the inductance of the stator winding. r L is the inductance of the rotor winding. m G is the magnetizing inductance between the stator winding and the rotor winding; i Indicates the current loop controller gain; Original transfer function The phase is In the original transfer function Introducing a transfer function R(s) to make the subsynchronous frequency band phase of the transfer function R'(s) in... Between, making The phase in the subsynchronous frequency band is between [-90°, 0°].

5. The subsynchronous resonance suppression device for the wind-fire bundling and series-compensated external transmission system according to claim 4, characterized in that, The positive sequence impedance acquisition unit includes: The decoupling module is used to achieve dq decoupling control in the inner loop of the machine-side converter by using dq decoupling compensation and stator flux dynamic compensation. The matrix transformation module is used to transform the dq impedance matrix in the synchronous rotating coordinate system to the positive and negative sequence impedance matrix in the stationary coordinate system after dq decoupling control to obtain the positive sequence impedance of the doubly fed wind turbine terminal.

6. The subsynchronous resonance suppression device for the wind-fire bundling and series-compensated external transmission system according to claim 4, characterized in that, The damping characteristic changing unit includes: The new impedance characteristic acquisition module is used to introduce additional damping control of the machine-side converter based on stator current feedback to obtain new machine-side impedance characteristics on the stator port impedance characteristics obtained by the positive sequence impedance. The damping level changing module is used to adjust the control parameters of the transfer function R(s) according to the new terminal impedance characteristics, thereby changing the damping level of the doubly fed wind turbine in the subsynchronous frequency band.

7. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps of the subsynchronous resonance suppression method for the wind-fire bundling and series-compensated external transmission system as described in any one of claims 1 to 3.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the steps of the subsynchronous resonance suppression method for the wind-fire bundled transmission system according to any one of claims 1 to 3.

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