A method, system and apparatus for subsynchronous oscillation suppression

Abstract

This invention discloses a method, system, and apparatus for suppressing subsynchronous oscillations. The method includes: extracting the power angle deviation signal of a doubly-fed induction generator (DFIG); modulating and generating a subsynchronous component signal of the power angle deviation based on the power angle deviation signal of the DFIG; and superimposing the power angle deviation subsynchronous component signal onto the rotor side of the DFIG. q The voltage at the shaft control circuit is used to control the rotor. q The shaft voltage is compensated and controlled to suppress subsynchronous oscillations. This invention can effectively suppress subsynchronous oscillations caused by the grid connection of doubly-fed wind farms through series compensation lines, ensuring the stability of the power system.

Description

Technical Field

[0001] This invention relates to a method, system, and apparatus for suppressing subsynchronous oscillations, belonging to the field of grid-connected stability analysis and control technology for wind power systems. Background Technology

[0002] In recent years, subsynchronous oscillations caused by wind power system grid connection have become one of the serious threats to the safe and stable operation of power systems. With the construction and grid connection of more and more large-scale wind farms, subsynchronous oscillation accidents have occurred repeatedly in power grids across the country. Subsynchronous oscillations diverge rapidly, affect a wide area, and can easily cause damage to the wind turbine crowbar circuits, turbine disconnection from the grid, and complete wind farm shutdown, seriously affecting the safe and stable operation of power systems containing large-scale wind power.

[0003] Depending on the different mechanisms for suppressing subsynchronous oscillations, methods based on the wind farm's own frequency converter control system and methods based on primary electrical equipment can be used. The former mainly suppresses subsynchronous oscillations by designing an additional damping controller in the doubly fed wind turbine control system. These dampers are designed by selecting appropriate feedback signals as inputs to the damping controller, such as rotor speed, rotor current, or series capacitor voltage.

[0004] As can be seen from the definition of the power angle of a doubly-fed generator, the magnitude of the power angle is related to the rotor and excitation current of the doubly-fed wind turbine generator. It is a good reflection of the electrical and mechanical quantities of the doubly-fed wind turbine generator itself. Therefore, as a damping control signal, it has advantages such as easy control and sensitive detection. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method, system, and device for suppressing subsynchronous oscillations, which can effectively suppress subsynchronous oscillations caused by the grid connection of doubly-fed wind farms through series compensation lines, thus ensuring the stability of the power system. To achieve the above objective, this invention employs the following technical solution:

[0006] In a first aspect, the present invention provides a method for suppressing subsynchronous oscillations, the method comprising:

[0007] Extract the power angle deviation signal of the doubly-fed induction wind turbine;

[0008] Based on the power angle deviation signal of the doubly fed induction wind turbine, the power angle deviation subsynchronous component signal is modulated and generated.

[0009] The subsynchronous component signal of the power angle deviation is superimposed on the voltage of the q-axis control circuit on the rotor side of the doubly fed wind turbine to compensate and control the rotor q-axis voltage and suppress subsynchronous oscillation.

[0010] In conjunction with the first aspect, further, the extraction of the power angle deviation signal of the doubly-fed induction wind turbine includes:

[0011] Based on the fifth-order electromagnetic transient model of the doubly-fed induction generator in the dq coordinate system, the transient electromotive force, stator current and stator voltage, and rotor voltage components of the doubly-fed induction generator on the dq axis are obtained.

[0012] The fifth-order electromagnetic transient model of the doubly-fed induction generator in the dq coordinate system is transformed to polar coordinates to obtain the fifth-order electromagnetic transient equation of the doubly-fed induction generator in polar coordinates with the amplitude and phase of stator current and transient electromotive force as state variables. The phase of the transient electromotive force is the power angle deviation signal of the doubly-fed induction generator.

[0013] In conjunction with the first aspect, the generation of the success angle deviation subsynchronization component signal further includes:

[0014] The power angle deviation signal of the doubly fed induction wind turbine is input into the filtering stage to extract the subsynchronous signal;

[0015] The subsynchronous signal is sequentially input into the proportional element and the phase-shifting element to adjust the amplitude and phase of the subsynchronous signal, thereby generating the power angle deviation subsynchronous component signal used to suppress subsynchronous oscillation.

[0016] In conjunction with the first aspect, furthermore, the filtering stage employs a bandpass filter to extract the subsynchronous signal, and the characteristic frequency ω... c The subsynchronous oscillation mode frequency is set, and the signal in the subsynchronous frequency domain is extracted by adjusting the bandwidth of the filter. This signal is expressed by the transfer function of the following formula:

[0017] (1)

[0018] In equation (1), G1(s) is the bandpass filter, K1 is the filter gain, s is a complex variable, ξ is the damping coefficient, and ω c The characteristic angular frequency is denoted as ω.

[0019] In conjunction with the first aspect, the phase-shifting stage further includes multiple lead-lag correction stages, simultaneously adjusting the amplitude and phase of the subsynchronization signal, as expressed by the following transfer function:

[0020] (2)

[0021] In equation (2), G2(s) is the transfer function of the transposition, s is a complex variable, T1 is the lead time constant, and T2 is the lag time constant.

[0022] In a second aspect, the present invention provides a subsynchronous oscillation suppression system, comprising:

[0023] Measurement module: Extraction module: used to extract the power angle deviation signal of the doubly-fed induction wind turbine;

[0024] Modulation generation of power angle deviation subsynchronization component module: used to modulate and generate power angle deviation subsynchronization component signal based on the power angle deviation signal of doubly fed induction wind turbine;

[0025] Data processing module: used to superimpose the subsynchronous component signal of the power angle deviation onto the voltage of the q-axis control loop on the rotor side of the doubly fed wind turbine, and to compensate and control the rotor q-axis voltage to suppress subsynchronous oscillation.

[0026] In conjunction with the second aspect, further, the extraction module extracts the power angle deviation signal of the doubly-fed induction generator (DFIG) wind turbine, including: obtaining the components of the transient electromotive force, stator current, stator voltage, and rotor voltage of the DFIG wind turbine on the dq axis based on the 5th-order electromagnetic transient model of the DFIG wind turbine in the dq coordinate system; transforming the 5th-order electromagnetic transient model of the DFIG wind turbine in the dq coordinate system to polar coordinates to obtain the 5th-order electromagnetic transient equation of the DFIG wind turbine in polar coordinates with the amplitude and phase of the stator current and transient electromotive force as state variables, wherein the phase of the transient electromotive force is the power angle deviation signal of the DFIG wind turbine.

[0027] In conjunction with the second aspect, further, the power angle deviation generation module inputs the power angle deviation signal of the doubly fed induction wind turbine into the filtering stage to extract the subsynchronous signal; the subsynchronous signal is then input into the proportional stage and the phase shift stage in sequence to adjust the amplitude and phase of the subsynchronous signal, thereby generating a power angle deviation subsynchronous component signal used to suppress subsynchronous oscillation.

[0028] Thirdly, the present invention provides a subsynchronous oscillation suppression device, including an additional damping controller, wherein the additional damping controller is equipped with the system described in the second aspect, and the additional damping controller is disposed on the rotor-side frequency converter of the doubly fed induction wind turbine.

[0029] Fourthly, the present invention provides a method for verifying subsynchronous oscillation suppression, comprising:

[0030] A simulation model of a doubly fed wind power system connected to the grid via a series compensation line is built in PSCAD or EMTDC simulation software. After the subsynchronous oscillation is induced, the subsynchronous oscillation suppression method described in the first aspect is adopted.

[0031] The waveforms of the active and reactive power outputs of the wind farm, the waveforms of the power angle amplitude and the waveform of the internal electromotive force amplitude of the doubly fed induction wind turbine are compared with the waveforms without subsynchronous oscillation suppression to verify the effectiveness of suppressing subsynchronous oscillation.

[0032] Compared with the prior art, the beneficial effects achieved by the subsynchronous oscillation suppression method, system, and apparatus provided in the embodiments of the present invention include:

[0033] This invention extracts the power angle deviation signal of a doubly-fed induction generator (DFIG) wind turbine; generates a subsynchronous component signal of the power angle deviation based on this signal; and superimposes this subsynchronous component signal onto the voltage of the q-axis control loop on the rotor side of the DFIG wind turbine to compensate for and control the rotor q-axis voltage, thereby suppressing subsynchronous oscillations. This invention effectively suppresses subsynchronous oscillations in the power system, ensuring the safe grid-connected operation of the DFIG wind power system. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the superimposed signal in a subsynchronous oscillation suppression method provided in Embodiment 1 of the present invention;

[0035] Figure 2 This is a schematic diagram of the vectors of various variables of a doubly fed induction generator in a subsynchronous oscillation suppression method provided in Embodiment 1 of the present invention;

[0036] Figure 3 These are the waveforms of active power and reactive power of the wind farm in Embodiment 2 of the present invention;

[0037] Figure 4 These are the waveforms of the power angle amplitude and the internal potential amplitude of the doubly fed induction wind turbine in Embodiment 2 of the present invention. Detailed Implementation

[0038] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0039] Example 1:

[0040] This invention provides a method for suppressing subsynchronous oscillations, comprising:

[0041] Extract the power angle deviation signal of the doubly-fed induction wind turbine;

[0042] Based on the power angle deviation signal of the doubly fed induction wind turbine, the power angle deviation subsynchronous component signal is generated.

[0043] The subsynchronous component signal of the power angle deviation is superimposed on the voltage of the q-axis control circuit on the rotor side of the doubly fed wind turbine to compensate and control the rotor q-axis voltage and suppress subsynchronous oscillation.

[0044] The specific steps include:

[0045] Step 1: Extract the power angle deviation signal of the doubly-fed induction wind turbine.

[0046] Step 1.1: Based on the fifth-order electromagnetic transient model of the doubly-fed induction generator in the dq coordinate system, obtain the transient electromotive force, stator current and stator voltage, and rotor voltage components of the doubly-fed induction generator on the dq axis.

[0047] Specifically, the fifth-order electromagnetic transient model of a doubly-fed induction generator in the dq coordinate system is expressed by the following equation:

[0048] (1)

[0049] in, .

[0050] In equation (1), i ds and i qs These are the stator current components on the dq axis, respectively; and These are the transient potential components on the dq axis, respectively; v ds and v qs These are the stator voltages on the dq axes, respectively; v dr and v qr These are the rotor voltages on the dq axes, respectively; L s For the stator leakage inductance, L r For the leakage inductance of the rotor, L m For mutual inductance between stator and rotor; L ss For the stator equivalent mutual inductance, L ss =L m +L s L rr For the rotor equivalent mutual inductance, L rr =L m +L r ;R s R is the resistance of the stator. r The resistance of the rotor; s slip For the worsening, s slip =1-ω r ω r ω is the rotor speed; s For synchronous speed; H r T is the rotor inertia time constant; m This refers to mechanical torque.

[0051] Step 1.2: Transform the 5th order electromagnetic transient model of the doubly-fed induction generator in the dq coordinate system to polar coordinates to obtain the 5th order electromagnetic transient equation of the doubly-fed induction generator in polar coordinates with the amplitude and phase of the stator current and transient electromotive force as state variables. The phase of the transient electromotive force is the power angle deviation signal of the doubly-fed induction generator.

[0052] The transient electromotive force, stator current, stator voltage, and rotor voltage components of a doubly-fed induction generator (DFIG) wind turbine are transformed to polar coordinates, and their amplitudes and phase angles are used to describe the electrical quantities. Without loss of generality, the spatial relationships of these electrical quantities are expressed as follows: Figure 2 As shown in the figure. V s The magnitude of the stator voltage vector leads the d-axis by an angle α in space; v ds and v qs These are the projections of the stator voltage vector onto the dq axis, respectively; similarly, E' is the magnitude of the transient potential vector, leading the d-axis by an angle β. e , and These represent the projections of the transient potential vector onto the dq axis; and the rotor voltage vector. The angle leading the d-axis is θ; the current vector I s The angle leading the d-axis is β i Furthermore, the phase angle at which the transient potential leads the stator voltage is defined as δ, and the phase angle at which the stator current leads the stator voltage is defined as... .

[0053] The transient electromotive force, stator current, stator voltage, and rotor voltage components of a doubly-fed induction generator along the dq axis are expressed by the following formula:

[0054] (2)

[0055] The phase angles are related as follows:

[0056] (3).

[0057] The fifth-order electromagnetic transient model of a doubly-fed induction generator in the dq coordinate system is transformed to polar coordinates and expressed by the following equation:

[0058] (4)

[0059] The rotor dynamic equation is:

[0060] (5)

[0061] In equation (4), .

[0062] In equation (5), T j Let ω be the rotor's moment of inertia. r T is the rotor speed. m This refers to mechanical torque.

[0063] Using the amplitude and phase of stator current and transient electromotive force as state variables, the fifth-order electromagnetic transient equation of the doubly-fed induction wind turbine in polar coordinates is constructed, and the transient electromotive force phase δ is the deviation power angle of the doubly-fed induction wind turbine.

[0064] Step 2: Generate the power angle deviation subsynchronous component signal based on the power angle deviation signal of the doubly fed induction wind turbine.

[0065] Step 2.1: Input the power angle deviation signal of the doubly fed induction wind turbine into the filtering stage to extract the subsynchronous signal.

[0066] The filtering stage uses a bandpass filter to extract the subsynchronous signal, and the characteristic frequency ω c The subsynchronous oscillation mode frequency is set, and the signal in the subsynchronous frequency domain is extracted by adjusting the bandwidth of the filter. This signal is expressed by the transfer function of the following formula:

[0067] (6)

[0068] In equation (6), G1(s) is the bandpass filter, K1 is the filter gain, s is a complex variable, ξ is the damping coefficient, and ω c The characteristic angular frequency is denoted as ω.

[0069] Step 2.2: Input the subsynchronous signal into the proportional element and the phase shifter in sequence, adjust the amplitude and phase of the subsynchronous signal, and generate the power angle deviation subsynchronous component signal used to suppress the subsynchronous oscillation.

[0070] The proportional element is used to adjust the amplitude of the subsynchronization signal. If the proportional coefficient K δ If the ratio is too large, it can easily cause stability problems to the original system, while if the ratio is too small, it will weaken the suppression effect of the additional control signal on subsynchronous oscillation.

[0071] The phase-shifting stage includes multiple lead and lag correction stages, simultaneously adjusting the amplitude and phase of the subsynchronous signal, and is expressed by the following transfer function:

[0072] (7)

[0073] In equation (7), G2(s) is the transfer function of the transposition, s is a complex variable, T1 is the lead time constant, and T2 is the lag time constant.

[0074] Step 3: As Figure 1 As shown, the subsynchronous component signal of the power angle deviation is superimposed on the voltage of the q-axis control loop on the rotor side of the doubly fed wind turbine to form an additional damping controller, which is used to compensate and control the rotor q-axis voltage and suppress subsynchronous oscillation.

[0075] Figure 1 middle, , These are the reference values ​​for active and reactive power, respectively. , These are the actual values ​​of active and reactive power, respectively. , These are the reference values ​​for the rotor current components on the d-axis and q-axis, respectively. , These are the actual components of the rotor current on the d-axis and q-axis, respectively; , These are the actual components of the rotor voltage on the d-axis and q-axis, respectively; , For impedance parameters; proportionality coefficient; , These are the lead and lag time constants, respectively; This is the deviation of the work angle.

[0076] This invention can effectively suppress subsynchronous oscillations in power systems and ensure the safe grid-connected operation of doubly-fed wind power systems.

[0077] Example 2:

[0078] This invention provides a software system corresponding to the method described in Embodiment 1, namely a subsynchronous oscillation suppression system, comprising:

[0079] Extraction module: Used to extract the power angle deviation signal of the doubly-fed induction wind turbine;

[0080] Power angle deviation subsynchronization component module: used to modulate and generate the power angle deviation subsynchronization component signal based on the power angle deviation signal of the doubly fed induction wind turbine.

[0081] Data processing module: used to superimpose the subsynchronous component signal of the power angle deviation onto the voltage of the q-axis control loop on the rotor side of the doubly fed wind turbine, in order to compensate and control the rotor q-axis voltage and suppress subsynchronous oscillation.

[0082] The extraction module extracts the power angle deviation signal of the doubly-fed induction generator (DFIG) wind turbine, including: obtaining the components of transient electromotive force, stator current, stator voltage, and rotor voltage on the dq axis of the DFIG wind turbine based on the 5th-order electromagnetic transient model of the DFIG wind turbine in the dq coordinate system; transforming the 5th-order electromagnetic transient model of the DFIG wind turbine in the dq coordinate system to polar coordinates to obtain the 5th-order electromagnetic transient equation of the DFIG wind turbine in polar coordinates with the amplitude and phase of the stator current and transient electromotive force as state variables, where the phase of the transient electromotive force is the power angle deviation signal of the DFIG wind turbine.

[0083] The subsynchronous component module for generating the power angle deviation signal of the doubly fed induction wind turbine is input into the filtering stage to extract the subsynchronous signal. The subsynchronous signal is then input into the proportional stage and the phase shift stage in sequence to adjust the amplitude and phase of the subsynchronous signal, thereby generating the power angle deviation subsynchronous component signal used to suppress subsynchronous oscillation.

[0084] Example 3:

[0085] This invention provides a subsynchronous oscillation suppression device, comprising: an additional damping controller, wherein the additional damping controller is equipped with a subsynchronous oscillation suppression system provided in Embodiment 2, and the additional damping controller is disposed on the rotor-side frequency converter of a doubly fed induction wind turbine generator.

[0086] Example 4:

[0087] This invention provides a method for verifying subsynchronous oscillation suppression, comprising:

[0088] A simulation model of a doubly fed wind power system connected to the grid via a series compensation line is built in PSCAD or EMTDC simulation software. After the subsynchronous oscillation is induced, a subsynchronous oscillation suppression method provided in Example 1 is adopted.

[0089] The waveforms of active and reactive power output from the wind farm, the waveforms of the power angle amplitude and the simulated waveforms of the doubly-fed induction wind turbine generator are compared with the waveforms without subsynchronous oscillation suppression to verify the effectiveness of suppressing subsynchronous oscillation.

[0090] A simulation model of a wind power system connected to the grid via a series-compensated line was built in the simulation system. The effectiveness of the additional damping controller was verified by activating the controller after inducing subsynchronous oscillations. A wind speed of 9 m / s and a series compensation degree of 70% were selected. The wind power system at this time contains a subsynchronous component of approximately 37 Hz. Therefore, the characteristic frequency of the bandpass filter was set. rad / s, and select the gain Damping coefficient After modulation, a proportional coefficient is set. Three phase-shifting stages are selected and connected in series, and then set... , The simulation time was 10s, during which subsynchronous oscillation was induced, and additional damping control was applied after 0.2s.

[0091] The simulated waveforms of active power P and reactive power Q of a wind farm are as follows: Figure 3 As shown, for better comparison, the simulated waveforms of power P' and Q' without subsynchronous oscillation suppression are also given in the figure. Figure 3It can be seen that after adopting the subsynchronous oscillation suppression method provided in Example 1, the active and reactive power remain stable after a small fluctuation, while the power of the wind farm that does not adopt the subsynchronous oscillation suppression method provided in Example 1 completely loses stability in a short period of time.

[0092] Simulation waveform of the power angle amplitude of a doubly-fed induction wind turbine generator is as follows: Figure 4 As shown, for better comparison, the figure also presents the simulated waveform of the power angle amplitude of the doubly-fed induction wind turbine without subsynchronous oscillation suppression. Figure 4 As can be seen, after adopting the subsynchronous oscillation suppression method provided in Example 1, the generator power angle and internal potential energy can maintain stable operation, while the generator power angle and internal potential amplitude without adopting the subsynchronous oscillation suppression method provided in Example 1 lose stability more quickly. The simulation results verify the effectiveness of the subsynchronous oscillation suppression method provided in Example 1.

[0093] Example 5:

[0094] This invention also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps of the subsynchronous oscillation suppression method described in Embodiment 1.

[0095] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied 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.

[0096] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will 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 apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0097] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0098] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0099] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for suppressing subsynchronous oscillations, characterized in that, include: Extracting the power angle deviation signal of a doubly-fed induction generator; wherein, the extraction of the power angle deviation signal of the doubly-fed induction generator includes: Based on the fifth-order electromagnetic transient model of the doubly-fed induction generator in the dq coordinate system, the transient electromotive force, stator current and stator voltage, and rotor voltage components of the doubly-fed induction generator on the dq axis are obtained. The fifth-order electromagnetic transient model of the doubly-fed induction generator in the dq coordinate system is transformed to polar coordinates to obtain the fifth-order electromagnetic transient equation of the doubly-fed induction generator in polar coordinates with the amplitude and phase of stator current and transient electromotive force as state variables. The phase of the transient electromotive force is the power angle deviation signal of the doubly-fed induction generator. Based on the power angle deviation signal of the doubly-fed induction wind turbine, a power angle deviation subsynchronization component signal is modulated and generated; wherein, the modulation and generation of the power angle deviation subsynchronization component signal includes: The power angle deviation signal of the doubly-fed induction wind turbine is input into the filtering stage to extract the subsynchronous signal; the filtering stage uses a bandpass filter to extract the subsynchronous signal, and the characteristic frequency ω c The subsynchronous oscillation mode frequency is set, and the signal in the subsynchronous frequency domain is extracted by adjusting the bandwidth of the filter. This signal is expressed by the transfer function of the following formula: (1) In equation (1), G1(s) is the bandpass filter, K1 is the filter gain, s is a complex variable, ξ is the damping coefficient, and ω c The characteristic angular frequency; The subsynchronous signal is sequentially input into a proportional element and a phase-shifting element to adjust its amplitude and phase, generating a subsynchronous component signal for suppressing subsynchronous oscillations due to power angle deviation. The phase-shifting element includes multiple lead-lag correction elements, simultaneously adjusting the amplitude and phase of the subsynchronous signal, as expressed by the following transfer function: (2) In equation (2), G2(s) is the transfer function of the transposition process, s is a complex variable, T1 is the lead time constant, and T2 is the lag time constant; The subsynchronous component signal of the power angle deviation is superimposed on the voltage of the q-axis control circuit on the rotor side of the doubly fed wind turbine to compensate and control the rotor q-axis voltage and suppress subsynchronous oscillation.

2. A subsynchronous oscillation suppression system, characterized in that, include: Extraction module: Used to extract the power angle deviation signal of the doubly-fed induction wind turbine; The extraction module extracts the power angle deviation signal of the doubly-fed induction generator (DFIG) wind turbine, including: obtaining the components of transient electromotive force, stator current, stator voltage, and rotor voltage on the dq axis of the DFIG wind turbine based on the 5th order electromagnetic transient model of the DFIG wind turbine in the dq coordinate system; transforming the 5th order electromagnetic transient model of the DFIG wind turbine in the dq coordinate system to polar coordinates to obtain the 5th order electromagnetic transient equation of the DFIG wind turbine in polar coordinates with the amplitude and phase of the stator current and transient electromotive force as state variables, wherein the phase of the transient electromotive force is the power angle deviation signal of the DFIG wind turbine. A module for generating a power angle deviation subsynchronization component signal: used to modulate and generate a power angle deviation subsynchronization component signal based on the power angle deviation signal of the doubly-fed induction wind turbine; wherein, the modulation of the generated power angle deviation subsynchronization component signal includes: The power angle deviation signal of the doubly-fed induction wind turbine is input into the filtering stage to extract the subsynchronous signal; the filtering stage uses a bandpass filter to extract the subsynchronous signal, and the characteristic frequency ω c The subsynchronous oscillation mode frequency is set, and the signal in the subsynchronous frequency domain is extracted by adjusting the bandwidth of the filter. This signal is expressed by the transfer function of the following formula: (1) In equation (1), G1(s) is the bandpass filter, K1 is the filter gain, s is a complex variable, ξ is the damping coefficient, and ω c The characteristic angular frequency; The subsynchronous signal is sequentially input into a proportional element and a phase-shifting element to adjust its amplitude and phase, generating a subsynchronous component signal for suppressing subsynchronous oscillations due to power angle deviation. The phase-shifting element includes multiple lead-lag correction elements, simultaneously adjusting the amplitude and phase of the subsynchronous signal, as expressed by the following transfer function: (2) In equation (2), G2(s) is the transfer function of the transposition process, s is a complex variable, T1 is the lead time constant, and T2 is the lag time constant; Data processing module: used to superimpose the subsynchronous component signal of the power angle deviation onto the voltage of the q-axis control loop on the rotor side of the doubly fed wind turbine, and to compensate and control the rotor q-axis voltage to suppress subsynchronous oscillation.

3. A subsynchronous oscillation suppression device, characterized in that, It includes an additional damping controller, which is equipped with the system of claim 2, and the additional damping controller is located on the rotor-side frequency converter of the doubly fed induction wind turbine.

4. A method for verifying subsynchronous oscillation suppression, characterized in that, include: A simulation model of a doubly fed wind power system connected to the grid via a series compensation line is built in PSCAD or EMTDC simulation software, and the subsynchronous oscillation suppression method described in claim 1 is adopted after the subsynchronous oscillation is induced. The waveforms of the active and reactive power outputs of the wind farm, the waveforms of the power angle amplitude and the waveform of the internal electromotive force amplitude of the doubly fed induction wind turbine are compared with the waveforms without subsynchronous oscillation suppression to verify the effectiveness of suppressing subsynchronous oscillation.

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