Method for improving voltage and current cooperative control stability of generator excitation system
By generating a grid impedance-frequency curve through an excitation controller, identifying resonant risk frequency bands, dynamically adjusting channel gain weights, and implementing frequency band limiting, the problem of new oscillation risks arising when suppressing broadband oscillations in existing technologies is solved, thereby improving system stability and oscillation suppression efficiency.
Patent Information
- Application Number
- CN202510995230.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-18
- Publication Date
- 2025-10-31
AI Technical Summary
When suppressing broadband oscillations, existing technologies often alter the grid resonance characteristics through control measures, leading to new oscillation risks, reducing system stability, and making it difficult to suppress known oscillations while avoiding the initiation of new oscillations.
The system generates a grid impedance-frequency curve by using an excitation controller, identifies resonant risk frequency bands, dynamically adjusts channel gain weights, implements frequency band limiting, and ensures system stability through impedance closed-loop optimization.
It effectively suppresses known oscillations, prevents new frequency band oscillations, improves system stability margin, enhances oscillation suppression efficiency and accuracy, and maintains the safety of power grid impedance characteristics.
Smart Images
Figure CN120879653A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of power generation equipment technology, and specifically relates to a method for improving the stability of voltage and current coordinated control of a generator excitation system. Background Technology
[0002] With the widespread application of power electronic equipment in the power grid, the interaction between new energy generators and the power grid is becoming increasingly complex, and the problem of wideband oscillations is becoming more prominent. To suppress these oscillations covering the subsynchronous to supersynchronous frequency bands, existing technologies typically employ active damping control strategies. The control strategy generally involves injecting a compensation signal inversely to the oscillation to provide positive damping, thereby suppressing the oscillation. However, this method has significant drawbacks in practice. On the one hand, traditional single strong excitation or fixed-frequency band limiting control is difficult to adapt to the dynamic changes in oscillation frequency. Often, while suppressing oscillations in one frequency band, it may generate negative damping effects in other frequency bands, exciting new oscillations. On the other hand, although it can track the dominant oscillation frequency, the dynamic intervention behavior of the controller itself changes the equivalent impedance characteristics presented by the generator to the power grid. This impedance change induced by control may shift the original resonant point of the system to a new, unmonitored frequency band, or create new resonant coupling with other equipment in the power grid. Ultimately, although the old oscillations are suppressed, new, more unpredictable oscillations are excited, thus reducing the overall stability of the system. Therefore, how to effectively suppress broadband oscillations while avoiding the adverse effects of control measures on the grid resonance characteristics and preventing the risk of new oscillations is a technical problem that urgently needs to be solved in this field. Summary of the Invention
[0003] To address the shortcomings of existing technologies, this invention provides a method for improving the stability of voltage and current coordinated control in a generator excitation system, thereby solving the aforementioned technical problems.
[0004] A method for improving the stability of a generator excitation system through coordinated voltage and current control includes the following steps:
[0005] Voltage and current signals at the generator terminals are acquired by a broadband measurement device and transmitted to the excitation controller. The excitation controller generates the grid impedance-frequency curve at the generator terminals based on the voltage and current signals using fast Fourier transform and Prony algorithm.
[0006] The excitation controller calculates the resonance risk index based on the grid impedance-frequency curve, and when the resonance risk index exceeds a preset threshold, it determines the corresponding resonance frequency band as a restricted frequency band.
[0007] The excitation controller decomposes the excitation current command into low-frequency, medium-frequency, and high-frequency signals through a bandpass filter bank, and dynamically adjusts the gain weight of each channel according to the real-time oscillation frequency monitored by the wideband measurement device.
[0008] The excitation controller limits the amplitude of the excitation current command within the restricted frequency band formed by the predetermined frequency range extending above and below the restricted frequency band and its boundary.
[0009] The excitation controller compares the generated grid impedance-frequency curve with the preset target impedance curve and optimizes the parameters of its internal damping controller in real time using a gradient descent algorithm.
[0010] Preferably, when the excitation controller calculates the resonance risk index based on the grid impedance-frequency curve, it specifically uses the following formula:
[0011]
[0012] in, This is a quantification value for the resonance risk. For frequency scanning points, The equivalent impedance on the generator side. The equivalent impedance on the grid side. For impedance phase difference, This is the phase stability factor.
[0013] Preferably, the broadband measurement device specifically includes:
[0014] Current sensor to monitor generator terminal current signal;
[0015] Voltage sensor to monitor generator terminal voltage signal;
[0016] An analog-to-digital converter performs analog-to-digital conversion on the output data of the current sensor and the voltage sensor.
[0017] The communication module is used for data synchronization with the power grid synchronization phasor measurement unit based on the IEEE C37.118.2 protocol.
[0018] Preferably, when dynamically adjusting the gain weight of each channel based on the real-time oscillation frequency monitored by the broadband measurement device, the following formula is specifically used:
[0019]
[0020] in, For frequency-varying damping gain, For the maximum allowable gain, For the target frequency point, For real-time oscillation frequency, This is the gain distribution bandwidth coefficient.
[0021] Preferably, the amplitude limitation of the excitation current command is specifically performed through an FIR band-stop filter. The center frequency of the stopband of the FIR band-stop filter is the center frequency of the restricted frequency band, the stopband width is 3Hz above and below the center frequency, and the amplitude limitation is 10% of the rated excitation current.
[0022] Preferably, the gradient descent algorithm is as follows:
[0023]
[0024] in, To measure the generator impedance, The target impedance curve, For the damping control parameter vector, This is the regularization coefficient.
[0025] Preferably, the excitation controller adopts a dual digital signal processor hot-standby architecture, including a main DSP and a coprocessor, wherein:
[0026] The main DSP executes the steps of the method;
[0027] The coprocessor monitors the trajectory of the power grid impedance-frequency curve in real time, and triggers a gradient rise blocking mechanism when an abnormal trajectory is detected.
[0028] Preferably, when the excitation controller starts wideband damping control, the distance protection transient exceedance criterion at the generator end is locked.
[0029] The overcurrent protection setting is dynamically adjusted based on the amplitude of the high-frequency component of the excitation current, with the adjustment range within 20% of the rated value.
[0030] Preferably, the following steps are also included:
[0031] The voltage drop rate of the generator terminals is detected. When the voltage drop rate is greater than 10% / ms, the amplitude limit of the excitation current command within the restricted frequency band is lifted.
[0032] Enable the strong excitation function to support voltage recovery.
[0033] Preferably, on-site verification is achieved by injecting a pseudo-random binary signal, specifically including the following steps:
[0034] In the generator excitation system, a pseudo-random binary signal with a frequency range of 0-500Hz and an amplitude not exceeding 2% of the rated excitation current is injected as a disturbance signal.
[0035] Within the restricted frequency band, the oscillation amplitude caused by the disturbance signal is suppressed by more than 60% within 200ms.
[0036] The beneficial effects of this invention are as follows: While suppressing known oscillations, this method also actively avoids interference with the inherent resonant characteristics of the power grid through hard limiting of the dynamic restricted frequency band, effectively preventing secondary risks of new frequency band oscillations induced by the control behavior itself, and greatly improving the stability margin of the system under complex operating conditions. Simultaneously, through adaptive channel weighting, damping control resources are allocated on demand, improving the suppression efficiency and accuracy of broadband oscillations. Furthermore, the impedance closed-loop optimization mechanism ensures that the overall impedance characteristics of the system remain safe at all times. Attached Figure Description
[0037] To more clearly illustrate the technical solutions in the embodiments of this application 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 this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0038] Figure 1 This is a flowchart illustrating a method for improving the stability of a generator excitation system through coordinated control of voltage and current, as provided by the present invention. Detailed Implementation
[0039] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.
[0040] The following disclosure provides many different embodiments or examples for implementing different structures of the present invention. To simplify the disclosure of the present invention, the components and arrangements of specific examples are described below. Of course, these are merely examples and are not intended to limit the present invention.
[0041] The embodiments of the invention will now be described in detail with reference to the accompanying drawings.
[0042] like Figure 1 As shown, a method for improving the stability of a generator excitation system through coordinated voltage and current control includes the following steps:
[0043] Voltage and current signals at the generator terminals are acquired by a broadband measurement device and transmitted to the excitation controller. The excitation controller generates the grid impedance-frequency curve at the generator terminals based on the voltage and current signals using fast Fourier transform and Prony algorithm.
[0044] The excitation controller calculates the resonance risk index based on the grid impedance-frequency curve, and when the resonance risk index exceeds a preset threshold, it determines the corresponding resonance frequency band as a restricted frequency band.
[0045] The excitation controller decomposes the excitation current command into low-frequency, medium-frequency, and high-frequency signals through a bandpass filter bank, and dynamically adjusts the gain weight of each channel according to the real-time oscillation frequency monitored by the wideband measurement device.
[0046] The excitation controller limits the amplitude of the excitation current command within the restricted frequency band formed by the predetermined frequency range extending above and below the restricted frequency band and its boundary.
[0047] The excitation controller compares the generated grid impedance-frequency curve with the preset target impedance curve and optimizes the parameters of its internal damping controller in real time using a gradient descent algorithm.
[0048] In its implementation, this scheme first uses a wideband measurement device with a bandwidth of at least 2kHz to rapidly acquire the dynamic voltage and current signals at the generator outlet. The excitation controller receives this raw data and uses a combination of Fast Fourier Transform and Prony algorithm to calculate a precise grid impedance-frequency characteristic curve covering 0.1Hz to 1000Hz in real time. Next, the controller analyzes this curve, quantifying resonance risk by calculating key indicators such as impedance amplitude and phase crossover. Once an indicator exceeds a preset safety threshold, the frequency point and its adjacent area are immediately marked as a "forbidden zone," thus accurately pinpointing potential instability sources. The safety threshold is generally set as a sharp increase in impedance amplitude or a drastic phase jump at a certain frequency point. This method decomposes the excitation current command into three control channels of low, medium, and high frequencies, and adaptively adjusts the gain weight of each channel based on the dominant oscillation frequency monitored in real time by the wideband measurement device, precisely targeting the most needed frequency bands for suppression. Subsequently, within the identified restricted frequency band and a protection band extending ±3Hz above and below it, the controller applies strict amplitude limits to the excitation current command using a digital band-stop filter, forming a dynamic control restricted area. This hard limiting measure fundamentally avoids resonance point drift caused by controller intervention. Finally, the controller continuously compares the real-time measured impedance curve with a target impedance curve representing the ideal stable state and uses optimization algorithms such as gradient descent to continuously fine-tune the parameters of the internal damping controller, ensuring that the generator's equivalent impedance characteristics are always constrained and tend towards the optimal safety target. Compared to existing technologies, this method, while suppressing known oscillations, also actively avoids interference with the inherent resonance characteristics of the power grid through hard limiting of the dynamic restricted frequency band, effectively preventing the secondary risk of new frequency band oscillations induced by the control behavior itself, and greatly improving the system's stability margin under complex operating conditions. At the same time, through adaptive channel weighting, damping control resources are allocated on demand, improving the suppression efficiency and accuracy of broadband oscillations. The impedance closed-loop optimization mechanism ensures that the overall impedance characteristics of the system remain safe.
[0049] More specifically, when the excitation controller calculates the resonance risk index based on the grid impedance-frequency curve, it uses the following formula:
[0050]
[0051] in, This is a quantification value for the resonance risk. For frequency scanning points, The equivalent impedance on the generator side. The equivalent impedance on the grid side. For impedance phase difference, This is the phase stability factor.
[0052] More specifically, the broadband measurement device includes:
[0053] Current sensor to monitor generator terminal current signal;
[0054] Voltage sensor to monitor generator terminal voltage signal;
[0055] An analog-to-digital converter performs analog-to-digital conversion on the output data of the current sensor and the voltage sensor.
[0056] The communication module is used for data synchronization with the power grid synchronization phasor measurement unit based on the IEEE C37.118.2 protocol.
[0057] Among them, the bandwidth of the current sensor is not less than 2kHz, the bandwidth of the voltage sensor is not less than 2kHz, the sampling rate of the analog-to-digital converter is not less than 100kS / s, and through the communication module, the phase angle of the voltage and current measured locally can be accurately compared with the phase angle of other nodes in the entire network.
[0058] More specifically, when dynamically adjusting the gain weight of each channel based on the real-time oscillation frequency monitored by the broadband measurement device, the following formula is used:
[0059]
[0060] in, For frequency-varying damping gain, For the maximum allowable gain, For the target frequency point, For real-time oscillation frequency, This is the gain distribution bandwidth coefficient.
[0061] More specifically, the amplitude limitation of the excitation current command is specifically performed through an FIR band-stop filter. The center frequency of the stopband of the FIR band-stop filter is the center frequency of the restricted frequency band, the stopband width is 3Hz above and below the center frequency, and the amplitude limit is 10% of the rated excitation current.
[0062] After the restricted frequency bands of the power grid are calibrated through wideband measurement and algorithm analysis at the front end, the digital signal processing unit in the excitation controller instantly generates and activates a specially customized finite impulse response bandstop filter. The center frequency of the filter's stopband is precisely set to the center frequency of the identified restricted frequency band. For example, if a resonance risk is detected at 80Hz, the filter's center is locked at 80Hz. Its stopband width is set to 3Hz above and below the center frequency. This width completely covers the resonance peak while avoiding excessive suppression, ensuring the accuracy of suppression. At the same time, this filter forcibly reduces the amplitude of all frequency components in the excitation current command that fall within this stopband to no more than 10% of the rated excitation current, ensuring that the controller does not output any energy that may aggravate oscillations to this frequency band, thus ensuring that the normal damping function in the safe frequency band is not affected.
[0063] More specifically, the gradient descent algorithm is shown in the following equation:
[0064]
[0065] in, To measure the generator impedance, The target impedance curve, For the damping control parameter vector, This is the regularization coefficient.
[0066] More specifically, the excitation controller adopts a dual digital signal processor hot-standby architecture, including a main DSP and a coprocessor, wherein:
[0067] The main DSP executes the steps of the method;
[0068] The coprocessor monitors the trajectory of the power grid impedance-frequency curve in real time, and triggers a gradient rise blocking mechanism when an abnormal trajectory is detected.
[0069] The main DSP is responsible for executing the core algorithm of the entire method to ensure the stability and efficiency of the system under normal and micro-disturbance conditions. The coprocessor continuously monitors the dynamic trajectory of the grid impedance-frequency curve generated by the main DSP in real time at extremely high frequency, while simultaneously comparing the current impedance curve with the curve from the previous moment and a preset safety envelope. Once an abnormal trajectory is detected—for example, a sudden and sharp increase in the slope of the impedance curve at a certain frequency point, far exceeding the normal fluctuation range, or a divergent and malignant change in the curve shape that cannot be corrected by conventional damping control—the coprocessor makes an immediate judgment. At this point, it immediately triggers the highest-priority gradient rise blocking mechanism. This mechanism bypasses the main DSP and directly issues a strong intervention command to the excitation output unit. In practical applications, the gradient rise blocking mechanism generally employs the following methods: instantaneously locking or significantly attenuating the output of the excitation regulator; forcibly switching the control mode to a predefined, absolutely safe conservative state.
[0070] More specifically, when the excitation controller starts wideband damping control, the distance protection transient exceedance criterion at the generator end is locked.
[0071] The overcurrent protection setting is dynamically adjusted based on the amplitude of the high-frequency component of the excitation current, with the adjustment range within 20% of the rated value.
[0072] When the main DSP's wideband damping control algorithm is activated and begins injecting high-frequency, dynamically changing damping current into the excitation winding, the controller immediately sends a clear "K-block B" logic signal to the digital distance protection device at the generator outlet. Upon receiving this signal, the protection device temporarily disables its internal transient overrun criterion used to distinguish between transient power oscillations and actual short-circuit faults. This criterion typically operates based on the rate of change of the impedance trajectory, while the high-frequency current injected by wideband damping causes severe and rapid fluctuations in the measured impedance. By actively blocking this criterion during damping control activation, the protection device is informed in advance that the current high-frequency fluctuations are actively generated by the excitation controller to suppress oscillations, and are not actual faults. Secondly, during the dynamic setting of overcurrent protection, the excitation controller continuously analyzes its actual output excitation current and, using its internal signal processing capabilities, accurately calculates the effective value or peak amplitude of the high-frequency component in the current. Then, it dynamically and continuously adjusts the operating settings of the downstream overcurrent protection components according to a preset ratio based on this real-time changing high-frequency component amplitude. The general ratio is set as follows: for every 1 ampere increase in the high-frequency component, the setpoint is increased by 0.1 amperes. The total increase is strictly limited to no more than 20% of the rated setpoint of the protection. This ensures that under strongly damped conditions, when the total current increases due to the injection of high-frequency current, conventional overcurrent protection will not misjudge it as an overload or fault and trip. At the same time, the 20% upper limit ensures that the sensitivity of the protection is not excessively sacrificed, and the protection can still operate reliably for real short-circuit currents that far exceed the range.
[0073] More specifically, it also includes the following steps:
[0074] The voltage drop rate of the generator terminals is detected. When the voltage drop rate is greater than 10% / ms, the amplitude limit of the excitation current command within the restricted frequency band is lifted.
[0075] Enable the strong excitation function to support voltage recovery.
[0076] A voltage sag rate greater than 10% / ms is a typical indicator of a near-field, high-impact short-circuit fault. In this situation, the excitation controller determines that the system has entered an emergency fault state, and its primary task is no longer to suppress oscillations, but to maintain voltage. At this time, the excitation controller will forcibly remove the amplitude limits of the FIR band-stop filters previously set on all restricted frequency bands to suppress oscillations. This causes the output command of the excitation regulator to no longer follow the conventional PID or damped control algorithm, but to jump directly to the physical limit allowed by the system design, i.e., the strong excitation peak value, injecting a huge amount of magnetic field energy into the generator rotor at the fastest speed, greatly improving the generator set's low-voltage / high-voltage fault ride-through capability.
[0077] More specifically, on-site verification is achieved by injecting pseudo-random binary signals, which includes the following steps:
[0078] In the generator excitation system, a pseudo-random binary signal with a frequency range of 0-500Hz and an amplitude not exceeding 2% of the rated excitation current is injected as a disturbance signal.
[0079] Within the restricted frequency band, the oscillation amplitude caused by the disturbance signal is suppressed by more than 60% within 200ms.
[0080] During normal grid-connected operation of the unit, a built-in pseudo-random binary signal generator is activated through the maintenance interface of the excitation controller. This generator produces a special digital signal with mathematically white noise characteristics and injects it into the command channel of the excitation current. The frequency range of this pseudo-random binary signal is set between 0-500Hz, sufficient to cover all potential oscillation frequency bands from low to high frequencies; its amplitude does not exceed 2% of the rated excitation current, generating extremely weak disturbances that are almost imperceptible to the vast power system, ensuring absolute safety during the test and preventing any impact on grid stability. After this tiny disturbance signal is injected, the wideband measurement device within the excitation controller accurately captures the weak voltage and current responses excited by this pseudo-random binary disturbance at various frequency points. This verifies the system's ability to suppress restricted frequency bands: the controller automatically analyzes the initial amplitude of the oscillations induced by the pseudo-random binary signal within the pre-calibrated restricted frequency bands and continuously monitors the decay process of these oscillations. In practical implementation, the amplitude of this oscillation must be suppressed by more than 60% within an extremely short time of 200 milliseconds by the active damping control system. If this target is met, it proves that the FIR band-stop filter and the entire cooperative control strategy are truly effective and respond quickly; otherwise, it indicates that there are design flaws or parameter tuning problems in the system.
[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.
Claims
1. A method for improving the stability of a generator excitation system through coordinated voltage and current control, characterized in that, Includes the following steps: Voltage and current signals at the generator terminals are acquired by a broadband measurement device and transmitted to the excitation controller. Based on these signals, the excitation controller generates a grid impedance-frequency curve at the generator terminals using a Fast Fourier Transform (FFT) and the Prony algorithm. The excitation controller calculates a resonance risk index based on this curve, and when the index exceeds a preset threshold, it designates the corresponding resonant frequency band as a restricted frequency band. The excitation controller decomposes the excitation current command into low-frequency, mid-frequency, and high-frequency channels using a bandpass filter bank, and dynamically adjusts the gain weight of each channel based on the real-time oscillation frequency monitored by the broadband measurement device. Within the restricted frequency band and the predetermined frequency range extending above and below its boundary, the excitation controller limits the amplitude of the excitation current command. The generated grid impedance-frequency curve is compared with a preset target impedance curve, and the parameters of its internal damping controller are optimized in real-time using a gradient descent algorithm.
2. The method for improving the stability of generator excitation system voltage and current coordinated control according to claim 1, characterized in that, When the excitation controller calculates the resonance risk index based on the grid impedance-frequency curve, it specifically uses the following formula: in, This is a quantification value for the resonance risk. For frequency scanning points, The equivalent impedance on the generator side. The equivalent impedance on the grid side. For impedance phase difference, This is the phase stability factor.
3. The method for improving the stability of generator excitation system voltage and current coordinated control according to claim 1, characterized in that, The broadband measurement device specifically includes: a current sensor for monitoring generator terminal current signals; a voltage sensor for monitoring generator terminal voltage signals; an analog-to-digital converter for converting the output data of the current sensor and the output data of the voltage sensor into analog and digital signals; and a communication module for synchronizing data with the power grid synchronization phasor measurement unit based on the IEEE C37.118.2 protocol.
4. The method for improving the stability of generator excitation system voltage and current coordinated control according to claim 1, characterized in that, When dynamically adjusting the gain weight of each channel based on the real-time oscillation frequency monitored by the broadband measurement device, the following formula is specifically used: in, For frequency-varying damping gain, For the maximum allowable gain, For the target frequency point, For real-time oscillation frequency, This is the gain distribution bandwidth coefficient.
5. The method for improving the stability of generator excitation system voltage and current coordinated control according to claim 1, characterized in that, The amplitude limitation of the excitation current command is specifically performed through an FIR band-stop filter. The center frequency of the stopband of the FIR band-stop filter is the center frequency of the restricted frequency band, the stopband width is 3Hz above and below the center frequency, and the amplitude limit is 10% of the rated excitation current.
6. The method for improving the stability of generator excitation system voltage and current coordinated control according to claim 1, characterized in that, The gradient descent algorithm is specifically shown in the following equation: in, To measure the generator impedance, The target impedance curve, For the damping control parameter vector, is the regularization coefficient.
7. The method for improving the stability of generator excitation system voltage and current coordinated control according to claim 1, characterized in that, The excitation controller adopts a dual digital signal processor hot backup architecture, including a main DSP and a coprocessor, wherein: the main DSP executes the steps of the method; the coprocessor monitors the trajectory of the grid impedance-frequency curve in real time, and triggers a gradient rise blocking mechanism when an abnormal trajectory is detected.
8. The method for improving the stability of generator excitation system voltage and current coordinated control according to claim 1, characterized in that, When the excitation controller starts wideband damping control, the distance protection transient overrun criterion at the generator end is locked; the overcurrent protection setting is dynamically adjusted according to the amplitude of the high-frequency component of the excitation current, and the adjustment range is within 20% of the rated value.
9. The method for improving the stability of generator excitation system voltage and current coordinated control according to claim 1, characterized in that, It also includes the following steps: The voltage drop rate at the generator terminals is detected. When the voltage drop rate is greater than 10% / ms, the amplitude limit of the excitation current command within the restricted frequency band is lifted; the strong excitation function is enabled to support voltage recovery.
10. The method for improving the stability of generator excitation system voltage and current coordinated control according to claim 1, characterized in that, Field verification is achieved by injecting a pseudo-random binary signal, specifically including the following steps: injecting a pseudo-random binary signal with a frequency range of 0-500Hz and an amplitude not exceeding 2% of the rated excitation current into the generator excitation system as a disturbance signal; within the restricted frequency band, the oscillation amplitude caused by the disturbance signal is suppressed by more than 60% within 200ms.