Wind power plant subsynchronous oscillation suppression system and method based on energy storage type SVG

Abstract

The invention discloses a wind power plant subsynchronous oscillation suppression system and method based on an energy storage type SVG, and relates to the technical field of power system stability control, and the system comprises a cascade H-bridge power module which is used for outputting the required reactive or active power; the isolated direct-current converter is connected between the energy storage unit and the cascaded H-bridge power module and is used for performing energy transmission and electrical isolation; the control strategy module is connected to the detection signal acquisition module and the cascaded H-bridge power module, and is used for receiving the output of the detection signal acquisition module and generating a control instruction for controlling the operation of a static var generator (SVG); and the pulse width modulation module is used for controlling the switching action of each H-bridge module according to the signal generated by the control strategy. According to the invention, a network construction type control strategy is constructed by adopting a network construction type control algorithm, so that the static var generator does not depend on a power grid phase-locked loop any more, voltage and frequency signals are generated autonomously, and system out-of-control caused by phase locking failure is avoided.

Description

Technical Field

[0001] This invention relates to the field of power system stability control technology, and in particular to a wind farm subsynchronous oscillation suppression system and method based on an energy storage SVG (static var generator). Background Technology

[0002] As wind power plays a vital role in the global energy landscape, large-scale grid connection of wind farms has become a trend. However, the transmission of power from wind farms via series compensation lines can trigger subsynchronous oscillations, threatening grid stability. Currently, adding damping control to the reactive power compensation equipment already in operation at wind farms is an effective solution to suppress these subsynchronous oscillations. Among available reactive power compensation equipment, SVG (Static Var Generator) dominates the market due to its simple structure, fast response, and low cost.

[0003] Existing subsynchronous oscillation suppression schemes for wind farms mainly rely on phase-locked loop (PLL) controlled SVG (Static Var Generator) or additional damping devices, which have the following shortcomings: 1) Traditional SVGs suffer from reduced control performance under weak grid conditions due to PLL lockout, failing to effectively suppress oscillations; 2) Simple reactive power compensation lacks active power support capabilities and is difficult to cope with frequency fluctuations; 3) Dedicated damping devices are costly and have slow response speeds, relying on complex parameter tuning; 4) Existing schemes mostly employ passive suppression, unable to dynamically adapt to different oscillation modes, and may affect the original stability of the system. Furthermore, research on the coordinated control of energy storage and SVG is insufficient, failing to fully leverage the advantages of grid-based control.

[0004] The purpose of this invention is to provide a wind farm subsynchronous oscillation suppression system based on an energy storage-type SVG. This device employs grid-based control, enabling the SVG to autonomously generate voltage, frequency, and phase, eliminating dependence on the grid's phase-locked loop and enhancing stability under weak grid conditions. Summary of the Invention

[0005] In view of the above-mentioned problems, the present invention is proposed.

[0006] Therefore, the problems to be solved by this invention are: traditional SVG has reduced control performance due to phase-locked loop loss under weak grid conditions, and cannot effectively suppress oscillations; simple reactive power compensation lacks active power support capability and is difficult to cope with frequency fluctuations; dedicated damping devices are costly and have slow response speed, and rely on complex parameter tuning; existing solutions mostly adopt passive suppression, which cannot dynamically adapt to different oscillation modes and may affect the original stability of the system.

[0007] To address the aforementioned technical problems, this invention provides the following technical solution: a wind farm subsynchronous oscillation suppression system based on an energy storage-type SVG, comprising: a cascaded H-bridge power module for outputting the required reactive or active power; an energy storage unit for providing fast-response active power support; an isolated DC-DC converter connected between the energy storage unit and the cascaded H-bridge power module for energy transmission and electrical isolation; a detection signal acquisition module for real-time acquisition of voltage and current signals at the wind farm grid connection point, and for signal filtering and conditioning; a control strategy module connected to the detection signal acquisition module and the cascaded H-bridge power module for receiving the output of the detection signal acquisition module and generating control commands for controlling the operation of the static var generator (SVG); and a pulse width modulation module for controlling the switching action of each H-bridge module according to the signal generated by the control strategy.

[0008] As a preferred embodiment of the wind farm subsynchronous oscillation suppression system based on energy storage SVG described in this invention, the cascaded H-bridge power module is composed of several cascaded H-bridge converters, and the DC side of each H-bridge is connected to the energy storage unit through an independent isolated DC-DC converter.

[0009] As a preferred embodiment of the wind farm subsynchronous oscillation suppression system based on energy storage SVG described in this invention, the isolated DC-DC converter adopts a dual active bridge topology and the switching frequency is set at 10-20kHz, so that bidirectional energy flow is generated between the energy storage unit and the cascaded H-bridge power module, and electrical isolation is performed to achieve fast dynamic response.

[0010] As a preferred embodiment of the wind farm subsynchronous oscillation suppression system based on energy storage SVG described in this invention, the energy storage unit includes a lithium-ion battery, a supercapacitor, or a combination of a lithium-ion battery and a supercapacitor, and is charged and discharged through an isolated DC-DC converter.

[0011] As a preferred embodiment of the wind farm subsynchronous oscillation suppression system based on energy storage SVG described in this invention, the control strategy module includes: a grid-type control unit, used to generate a voltage reference signal autonomously by simulating the external characteristics of a synchronous generator using a grid-type control algorithm; a damping control unit, used to generate a reverse damping command based on the detected subsynchronous oscillation component and superimpose it onto the grid-type control loop; and an impedance reshaping unit, used to control the static var generator SVG to exhibit negative resistance characteristics in the subsynchronous frequency band, thereby blocking the oscillation path.

[0012] As a preferred embodiment of the wind farm subsynchronous oscillation suppression system based on energy storage SVG described in this invention, the grid-type control unit includes a voltage outer loop, a current inner loop, and a power control loop, and adopts a grid-type control algorithm for autonomous generation and synchronous control of voltage and frequency.

[0013] The beneficial effects of this preferred technical solution are as follows: the grid-type control unit simulates the characteristics of a synchronous generator through a grid-type control algorithm, autonomously constructs a voltage or frequency reference, and achieves stable support for the grid voltage and frequency, replacing the traditional method that relies on phase-locked loops, effectively solving the problem of instability caused by the loss of lock-in in traditional SVG under weak grid or voltage distortion environments.

[0014] As a preferred embodiment of the wind farm subsynchronous oscillation suppression system based on energy storage SVG described in this invention, the damping control unit includes: a bandpass filter for extracting the subsynchronous component from the voltage or current signal; a phase compensator for adjusting the phase of the extracted signal; and a gain regulator for amplifying or attenuating the damping signal.

[0015] The beneficial effects of this preferred technical solution are as follows: by using a bandpass filter to extract the subsynchronous oscillation frequency component in the voltage or current, the subsynchronous oscillation component of the wind farm can be accurately identified and responded to. The source of oscillation energy can be canceled by the inverted signal, thereby enhancing the pertinence and proactivity of oscillation suppression.

[0016] As a preferred embodiment of the wind farm subsynchronous oscillation suppression system based on energy storage SVG described in this invention, the SVG is not only used for conventional reactive power compensation, but also removes subsynchronous harmonic components by adding a second-order notch filter, and combines the subsynchronous damping control of the damping control unit to suppress subsynchronous oscillation by adjusting the phase angle.

[0017] As a preferred embodiment of the wind farm subsynchronous oscillation suppression system based on energy storage SVG described in this invention, the pulse width modulation module adopts a modulation strategy to generate the drive signals required by each stage of the H-bridge module.

[0018] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for suppressing subsynchronous oscillations in wind farms based on energy storage-type SVG, comprising: a detection signal acquisition module acquiring voltage and current signals at the grid connection point of the wind farm in real time, and filtering and conditioning the signals; extracting the subsynchronous oscillation frequency components contained in the acquired voltage or current signals through bandpass filtering logic within the control strategy module, for identifying the existence and characteristics of oscillations; the control strategy module generating a fundamental control signal for maintaining system voltage and frequency stability based on a grid-type control algorithm and the system operating state; and the control strategy... The module simultaneously generates a reverse damping control signal based on the extracted subsynchronous oscillation component, after phase compensation and gain adjustment, to suppress oscillation energy. The fundamental control signal and the subsynchronous damping signal are superimposed and fused to form the final control command. The fused control command is sent to the pulse width modulation module, which uses a modulation strategy to control the switching devices in each stage of the H-bridge power module, thereby outputting the regulated current or voltage. According to the real-time active power demand of the system, the energy storage unit performs rapid charging and discharging through an isolated DC-DC converter to provide or absorb active power, forming a coordinated control mechanism for active and reactive power.

[0019] The beneficial effects of this invention are as follows: By using a grid-based control algorithm to construct a grid-based control strategy, the static var generator no longer relies on the grid phase-locked loop and can autonomously generate voltage and frequency signals, which significantly improves the stable operation capability in weak grid or voltage distortion environments and avoids system runaway due to phase-locked loop failure.

[0020] The damping control strategy integrated in this invention effectively cancels out the energy at the oscillation source by extracting the subsynchronous frequency component in real time and generating a phase-compensated reverse control signal that is superimposed on the control path. It has the ability to suppress vibration quickly, accurately, and with strong adaptability. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. 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.

[0022] Figure 1 This is a structural diagram of a wind farm subsynchronous oscillation suppression system based on an energy storage SVG in Example 1.

[0023] Figure 2 This is a control strategy diagram for a wind farm subsynchronous oscillation suppression system based on an energy storage SVG in Example 1. Detailed Implementation

[0024] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0025] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0026] Example 1, referring to Figure 1 and Figure 2 This is the first embodiment of the present invention, which provides a wind farm subsynchronous oscillation suppression system based on energy storage SVG, including, as follows: Figure 1 As shown:

[0027] Cascaded H-bridge power modules are used to output the required reactive or active power.

[0028] Energy storage units are used to provide fast-response active power support, where u c It is expressed as capacitor voltage.

[0029] An isolated DC / DC converter is connected between the energy storage unit and the cascaded H-bridge power module for energy transfer and electrical isolation.

[0030] The detection signal acquisition module is used to acquire voltage and current signals at the grid connection point of the wind farm in real time, and to perform signal filtering and conditioning.

[0031] The control strategy module is connected to the detection signal acquisition module and the cascaded H-bridge power module. It is used to receive the output of the detection signal acquisition module and generate control commands for controlling the operation of the static var generator (SVG).

[0032] And a pulse width modulation (PWM) module, used to control the switching action of each H-bridge module according to the signal generated by the control strategy.

[0033] Specifically, the cascaded H-bridge power module is composed of several cascaded H-bridge converters, and the DC side of each H-bridge is connected to the energy storage unit through an independent isolated DC-DC converter.

[0034] The isolated DC-DC converter adopts a dual active bridge topology with a switching frequency set at 10-20kHz, enabling bidirectional energy flow between the energy storage unit and the cascaded H-bridge power module, while providing electrical isolation to achieve a fast dynamic response.

[0035] The energy storage unit includes a lithium-ion battery, a supercapacitor, or a combination of lithium-ion batteries and supercapacitors, and is charged and discharged via an isolated DC-DC converter.

[0036] The control strategy module includes a network-type control unit, which uses a network-type control algorithm to simulate the external characteristics of a synchronous machine and autonomously generate a voltage reference signal.

[0037] The damping control unit is used to generate a reverse damping command based on the detected subsynchronous oscillation component and superimpose it onto the network control loop.

[0038] Impedance reshaping unit is used to control the static var generator (SVG) to exhibit negative resistance characteristics in the subsynchronous frequency band, thereby blocking the oscillation path.

[0039] The main control strategies of the control strategy module are as follows: Figure 2 As shown, the subsynchronous component is extracted by a bandpass filter, and after phase compensation and gain adjustment, a damping signal is generated and superimposed on the converter control loop.

[0040] Among them, u pcc Represented as the voltage value detected at the grid connection point, u sub This is represented as a voltage signal with the subsynchronous frequency component after bandpass filtering. This refers to the reference voltage signal used to control the SVG after bandpass filtering, phase compensation, and proportional adjustment, which is then input as a command to the SVG.

[0041] The network-type control unit includes an outer voltage loop, an inner current loop, and a power control loop, and uses a network-type control algorithm to autonomously generate and synchronize voltage and frequency.

[0042] In an optional embodiment, the network-based control algorithm can employ a network-based control strategy based on a Virtual Synchronous Generator (VSG), specifically including:

[0043] The difference between the active power of the SVG and the power grid is monitored in real time. This difference is then substituted into the "inertia + damping" model to obtain the active power command that the SVG should output. This model simulates the rotational equation behavior of a traditional synchronous generator to generate dynamic frequency adjustment.

[0044] Based on the power command, the target voltage amplitude and frequency are dynamically calculated, and the voltage phase angle signal simulating the rotation of the synchronous machine rotor is output for subsequent control.

[0045] The three-phase voltage reference signal generated by the VSG module is converted into dq coordinates, and the voltage command is sent to the current inner loop controller; the current controller outputs a modulation signal, which is then modulated by PWM to drive the H-bridge power module.

[0046] With load fluctuations or grid disturbances, the VSG automatically adjusts its output frequency and voltage, providing dynamic inertia support. It can simulate primary frequency regulation characteristics and achieve active or reactive power sharing with other power generation units.

[0047] In another optional embodiment, the mesh-based control algorithm can also employ a mesh-based control strategy based on droop control, specifically including:

[0048] During the system initialization phase, droop coefficients, such as frequency droop coefficients and voltage droop coefficients, are set, reference values, including target frequency and target voltage, are set, and the maximum allowable offset range is determined.

[0049] The control module monitors the active and reactive power output of the SVG in real time and updates the SVG output power feedback value according to load changes or oscillation response.

[0050] Based on the relationship between active power and frequency, the following adjustment mechanism is adopted:

[0051] When active power increases, the output frequency decreases slightly; when active power decreases, the output frequency increases slightly. Based on the relationship between reactive power and voltage, when reactive power increases, the SVG output voltage decreases slightly, and vice versa. This achieves automatic power distribution and balancing without the need for phase-locked loops or centralized control.

[0052] The calculated target voltage amplitude and frequency values ​​are converted into three-phase sinusoidal reference signals, which are then sent to the current inner loop controller and modulated to form a drive signal.

[0053] The pulse width modulation module controls the H-bridge to conduct according to the reference signal, realizing multi-level output, giving the SVG a certain "flexible power supply" characteristic, dynamically adapting to grid disturbances and power fluctuations.

[0054] It should be noted that the grid-based control algorithm enables the SVG to operate in a grid without relying on a phase-locked loop, thus improving its adaptability to weak grids; it provides frequency and voltage stability support, preventing wind farms from disconnecting from the grid due to voltage disturbances; it has a simulated inertial response function, improving the system's anti-disturbance capability; it can operate in coordination with energy storage units to form an active / reactive power linkage support mechanism; and it improves the intelligence level of SVG control, enhancing the overall stability of the system.

[0055] The damping control unit includes a bandpass filter for extracting the subsynchronous component from the voltage or current signal.

[0056] A phase compensator is used to adjust the phase of the extracted signal.

[0057] Gain regulators are used to amplify or attenuate damped signals.

[0058] The impedance reshaping unit includes an SVG that is not only used for conventional reactive power compensation, but also removes subsynchronous harmonic components by adding a second-order notch filter, and combines the subsynchronous damping control of the damping control unit to suppress subsynchronous oscillations by adjusting the phase angle.

[0059] The pulse width modulation (PWM) module employs a modulation strategy to generate the drive signals required by each stage of the H-bridge module.

[0060] In an optional embodiment, the modulation strategy may employ a carrier phase-shift modulation strategy to generate drive signals for each stage of the cascaded H-bridge module, specifically including the following steps:

[0061] First, determine the required number of cascaded H-bridge modules based on the system power rating and output voltage requirements. For example, if five H-bridges are cascaded, staggered drive signals need to be generated for each of the five H-bridges.

[0062] A common sinusoidal reference waveform is set for all H-bridges, representing the desired output voltage target, and is used for comparison with their respective carrier signals.

[0063] Each H-bridge is assigned a triangular wave carrier signal with the same frequency and amplitude but staggered phase. For example, if there are 5 H-bridges, the carrier phases are staggered by 72° (360° / 5) to ensure uniform distribution on the time axis and form a phase-shifted relationship.

[0064] A common sinusoidal reference signal is compared with the independent carrier triangular wave of each H-bridge. When the reference wave is higher than the carrier wave, a high level is output, and when it is lower than the carrier wave, a low level is output, thereby generating a set of independent PWM pulse signals for each H-bridge module.

[0065] Because of the phase difference between the carrier waves, the generated PWM signals will also be naturally staggered in time, forming interleaved modulation waveforms, thereby avoiding multiple modules from being turned on at the same time and reducing current surges and harmonic superposition.

[0066] The generated PWM signal is sent to the switching device inside the corresponding H-bridge module to drive it to turn on or off according to the set pulse, thereby controlling the output voltage of each H-bridge.

[0067] Because the PWM waveforms output by each H-bridge are staggered in timing and superimposed on each other, a multi-level, low-harmonic, high-resolution composite voltage waveform is finally formed at the AC output terminal, which meets the power grid's requirements for power quality.

[0068] In another optional embodiment, the modulation strategy may also employ a space vector modulation strategy to generate drive signals for each stage of the cascaded H-bridge module, specifically including the following steps:

[0069] The desired three-phase sinusoidal voltage signal is converted into a spatial vector form through coordinate transformation, which is used to determine the current target composite vector.

[0070] The space vector plane is divided into six basic sectors (each 60°). The sector where the current vector is located is determined based on the direction of the target vector. This is used to select two sets of active vectors and one set of zero vectors that may be used in this cycle.

[0071] Based on the angle and amplitude between the target vector and the fundamental vector, the duration of action of the two active vectors and one zero vector within the PWM cycle is accurately calculated.

[0072] Arrange the three vectors in the order of action according to the principle of minimum switching count or symmetry to form a switching sequence, ensuring the symmetry and modulation accuracy of the PWM waveform.

[0073] Based on the calculated operating time and switching sequence, a corresponding PWM control pulse signal is generated for each power switch and sent to the power module to drive the switching device to turn on or off according to the required rhythm.

[0074] It should be noted that by using a modulation strategy to perform PWM control on multiple H-bridge power units, precise and synchronized gating signals can be generated; controlling the output of multi-level H-bridge modules to output high-quality multi-level voltage waveforms can achieve smoothing of the output waveform and multi-level control, significantly reducing the harmonic content of the output voltage; improving the waveform quality and control accuracy of the SVG output current; reducing system electromagnetic interference and filter size requirements; supporting modular redundant design and scalability, and enhancing the maintainability and operational reliability of the equipment.

[0075] Example 2, the second embodiment of the present invention, differs from the first embodiment in that: a method for suppressing subsynchronous oscillations in wind farms based on energy storage SVG includes: a detection signal acquisition module acquiring voltage and current signals at the grid connection point of the wind farm in real time, and filtering and conditioning the signals; extracting the subsynchronous oscillation frequency components contained in the acquired voltage or current signals through bandpass filtering logic within the control strategy module, for identifying the existence and characteristics of oscillations; and the control strategy module generating a fundamental control signal for maintaining system voltage and frequency stability based on a grid-based control algorithm and the system operating state. The control strategy module simultaneously generates a reverse damping control signal based on the extracted subsynchronous oscillation component, after phase compensation and gain adjustment, to suppress oscillation energy. The fundamental control signal and the subsynchronous damping signal are superimposed and fused to form the final control command. The fused control command is sent to the pulse width modulation module, which uses a modulation strategy to control the switching devices in each stage of the H-bridge power module, thereby outputting the regulated current or voltage. According to the real-time active power demand of the system, the energy storage unit performs rapid charging and discharging through an isolated DC-DC converter to provide or absorb active power, forming a coordinated control mechanism for active and reactive power.

[0076] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A wind farm subsynchronous oscillation suppression system based on energy storage SVG, characterized in that: include, Cascaded H-bridge power modules are used to output the required reactive or active power; Energy storage units are used to provide fast-response active power support; An isolated DC-DC converter is connected between the energy storage unit and the cascaded H-bridge power module for energy transfer and electrical isolation. The detection signal acquisition module is used to acquire voltage and current signals at the grid connection point of the wind farm in real time, and to perform signal filtering and conditioning. The control strategy module is connected to the detection signal acquisition module and the cascaded H-bridge power module. It is used to receive the output of the detection signal acquisition module and generate control commands for controlling the operation of the static var generator (SVG). And a pulse width modulation module, used to control the switching action of each H-bridge module according to the signal generated by the control strategy.

2. The wind farm subsynchronous oscillation suppression system based on energy storage SVG as described in claim 1, characterized in that: The cascaded H-bridge power module is composed of several cascaded H-bridge converters, and the DC side of each H-bridge is connected to the energy storage unit through an independent isolated DC-DC converter.

3. The wind farm subsynchronous oscillation suppression system based on energy storage SVG as described in claim 2, characterized in that: The isolated DC-DC converter adopts a dual active bridge topology and sets the switching frequency to 10-20kHz, enabling bidirectional energy flow between the energy storage unit and the cascaded H-bridge power module, while providing electrical isolation to achieve rapid dynamic response.

4. The wind farm subsynchronous oscillation suppression system based on energy storage SVG as described in claim 3, characterized in that: The energy storage unit includes a lithium-ion battery, a supercapacitor, or a combination of a lithium-ion battery and a supercapacitor, and is charged and discharged through an isolated DC-DC converter.

5. The wind farm subsynchronous oscillation suppression system based on energy storage SVG as described in claim 4, characterized in that: The control strategy module includes, A network-type control unit is used to simulate the external characteristics of a synchronous machine and autonomously generate a voltage reference signal by employing a network-type control algorithm. The damping control unit is used to generate a reverse damping command based on the detected subsynchronous oscillation component and superimpose it onto the network control loop. Impedance reshaping unit is used to control the static var generator (SVG) to exhibit negative resistance characteristics in the subsynchronous frequency band, thereby blocking the oscillation path.

6. The wind farm subsynchronous oscillation suppression system based on energy storage SVG as described in claim 5, characterized in that: The network-type control unit includes a voltage outer loop, a current inner loop, and a power control loop, and uses a network-type control algorithm to autonomously generate and synchronously control voltage and frequency.

7. The wind farm subsynchronous oscillation suppression system based on energy storage SVG as described in claim 6, characterized in that: The damping control unit includes, A bandpass filter is used to extract the subsynchronous component from a voltage or current signal; A phase compensator is used to adjust the phase of the extracted signal; Gain regulators are used to amplify or attenuate damped signals.

8. The wind farm subsynchronous oscillation suppression system based on energy storage SVG as described in claim 6, characterized in that: The impedance reshaping unit includes an SVG that is not only used for conventional reactive power compensation, but also removes subsynchronous harmonic components by adding a second-order notch filter, and combines the subsynchronous damping control of the damping control unit to suppress subsynchronous oscillations by adjusting the phase angle.

9. A wind farm subsynchronous oscillation suppression system based on energy storage SVG as described in claim 6, characterized in that: The pulse width modulation module employs a modulation strategy to generate the drive signals required by each stage of the H-bridge module.

10. A method for suppressing subsynchronous oscillations in wind farms based on energy storage SVG, comprising applying a wind farm subsynchronous oscillation suppression system based on energy storage SVG as described in any one of claims 1 to 9, characterized in that: This includes a signal acquisition module that collects voltage and current signals at the wind farm's grid connection point in real time, and filters and conditions the signals; From the acquired voltage or current signals, the subsynchronous oscillation frequency components are extracted through the bandpass filtering logic inside the control strategy module to identify the presence and characteristics of oscillations. The control strategy module is based on a network-based control algorithm and generates a fundamental control signal to maintain system voltage and frequency stability according to the system operating status. The control strategy module simultaneously generates a reverse damping control signal based on the extracted subsynchronous oscillation component, after phase compensation and gain adjustment, to suppress oscillation energy. The fundamental control signal and the subsynchronous damping signal are superimposed and fused to form the final control command; The fused control command is sent to the pulse width modulation module, and the modulation strategy is used to control the switching devices in each stage of the H-bridge power module, thereby outputting the regulated current or voltage. Based on the real-time active power demand of the system, the energy storage unit performs rapid charging and discharging through an isolated DC-DC converter to provide or absorb active power, forming a coordinated control mechanism for active and reactive power.

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