Wide load variable speed cruise control method for supercritical coal-fired power generating units

Abstract

The application discloses a wide-load variable-speed cruise control method for a supercritical coal-fired power generating unit and relates to the technical field of data processing, and comprises the following steps: obtaining a valve position signal and a water flow signal of a feedwater recirculation valve of the coal-fired power generating unit and identifying a valve position oscillation interval; performing valve position disturbance on the feedwater recirculation valve in the valve position oscillation interval and extracting a feedwater flow change trajectory after the valve position disturbance; performing clustering analysis on the feedwater flow signal based on the feedwater flow change trajectory and constructing a signal separation topology according to an analysis result; identifying a propagation delay phase of the feedwater flow signal based on the signal separation topology, performing delay compensation on the propagation delay phase, and obtaining a valve position adjustment phase time sequence; and performing phase misplacement adjustment on a valve opening of the feedwater recirculation valve in a variable-speed reduction process based on the valve position adjustment phase time sequence, so that the problem that, when the coal-fired power generating unit is rapidly reduced in load, a feedwater adjustment valve is delayed in response and thus oscillation is caused, thereby leading to uncontrollable steam temperature, is solved.

Description

Technical Field

[0001] This invention relates to the field of data processing technology, and more specifically, to a wide-load variable-rate cruise control method for supercritical coal-fired power generating units. Background Technology

[0002] Supercritical coal-fired power generating units are large-scale thermal power generation equipment that achieves efficient energy conversion through high-parameter steam circulation and are widely used in the power generation field. During the operation of these units, the boiler feedwater regulation process directly affects the stability of the steam-water circulation and the accuracy of steam parameter control. Especially when the unit participates in deep peak shaving and wide-load operation, it is necessary to rapidly adjust the feedwater flow rate through actuators such as feedwater recirculation valves and feedwater regulating valves to adapt to changes in unit load. Among these, the feedwater recirculation valve, as a crucial regulating component connecting the feedwater regulation process and the boiler water circulation process, directly affects the feedwater flow rate response speed through its valve position changes, further influencing key operating parameters such as superheated steam temperature and reheated steam temperature. Therefore, the dynamic response characteristics of the feedwater recirculation valve are a vital factor in ensuring the stable operation of supercritical coal-fired power generating units under wide load conditions.

[0003] For example, the invention patent announcement CN119962347A discloses a method, terminal, and storage medium for optimizing the valve flow characteristics of thermal power units. The method includes the following steps: establishing an original valve flow characteristic dataset; based on the original valve flow characteristic dataset, and reasonably assuming the correspondence between the total valve position command and the pressure ratio using the equivalent steam flow method, establishing an original valve flow characteristic optimization dataset; based on the original valve flow characteristic optimization dataset, fitting and constructing an actual valve flow characteristic curve using an improved K-means clustering analysis algorithm; and optimizing the actual valve flow characteristic curve using an improved particle swarm optimization algorithm to obtain the optimized valve flow characteristic curve. This method avoids the problem of easily getting trapped in local optima during complex optimization and has high parameter identification accuracy and robustness.

[0004] However, during rapid load reduction in supercritical coal-fired power generating units, the actual adjustment process of the feedwater recirculation valve is affected by factors such as the inertia of the valve actuator, the lag in pipeline fluid, and the feedwater flow transmission process, resulting in a time offset between valve position changes and feedwater flow response. When the unit load continues to decrease, although the control command can quickly change the target opening of the feedwater recirculation valve, the actual feedwater flow cannot synchronously follow the load change due to the lag in the feedwater flow response. This can easily cause overshoot or undershoot in feedwater flow regulation, leading to an imbalance in the steam-water energy balance and causing periodic fluctuations or even overshoot and loss of control in steam temperature. Furthermore, existing control methods typically control the valve opening based on fixed adjustment parameters or preset response curves, which is difficult to adapt to the dynamic response differences under different load change rates during wide-load variable-speed load reduction. They cannot accurately identify the phase offset relationship between valve position changes and feedwater flow changes, resulting in a continuous misalignment between valve regulation actions and actual flow demand, further reducing the stability of steam temperature control during rapid load reduction.

[0005] To address the above problems, this invention proposes a solution. Summary of the Invention

[0006] To overcome the aforementioned deficiencies of the prior art, embodiments of the present invention provide a wide-load variable-rate cruise control method for supercritical coal-fired power generating units. By identifying the oscillation state of the feedwater recirculation valve and extracting the feedwater flow propagation delay characteristics, phase compensation and misalignment correction are performed on the valve position adjustment process to solve the problem that when the coal-fired power generating unit rapidly reduces the load, the feedwater regulating valve reacts lagily, which leads to oscillation and thus causes steam temperature runaway.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A wide-load variable-rate cruise control method for supercritical coal-fired power generating units includes the following steps: The system acquires the valve position signal and water flow signal of the feedwater recirculation valve of a coal-fired power generating unit, and identifies the valve position oscillation interval based on these signals. Within the oscillation interval, the system perturbs the valve position of the feedwater recirculation valve and extracts the feedwater flow change trajectory after the perturbation. Based on the feedwater flow change trajectory, the system performs cluster analysis on the feedwater flow signal and constructs a signal separation topology for the feedwater flow signal according to the analysis results. Based on the signal separation topology, the system identifies the propagation delay phase of the feedwater flow signal and performs delay compensation to obtain the valve position adjustment phase timing. Based on the valve position adjustment phase timing, the system performs phase misalignment adjustment of the valve opening of the feedwater recirculation valve during the variable speed reduction process.

[0009] In a preferred embodiment, the step of identifying the valve position oscillation interval based on the valve position signal and water flow signal specifically involves: performing time-frequency domain joint analysis on the valve position signal and water flow signal to obtain the dominant fluctuation component of the valve position signal; extracting the amplitude envelope of the dominant fluctuation component, and identifying the oscillation start time and oscillation end time of the valve position signal based on the amplitude envelope to obtain the valve position oscillation period; calculating the sliding window variance of the water flow signal within the valve position oscillation period, and identifying the flow fluctuation interval of the water flow signal based on the calculation result; extracting the intersection interval of the valve position oscillation period and the flow fluctuation interval on the time axis to obtain the oscillation coupling interval; calculating the time-domain cross-correlation function of the valve position signal and the water flow signal within the oscillation coupling interval, and calculating the peak phase offset of the cross-correlation function; and correcting the oscillation coupling interval based on the peak phase offset of the cross-correlation function to obtain the valve position oscillation interval.

[0010] In a preferred embodiment, the step of perturbing the feedwater recirculation valve within the valve position oscillation range and extracting the feedwater flow rate change trajectory after the valve position perturbation specifically involves: applying multi-level amplitude perturbation signals to the feedwater recirculation valve within the valve position oscillation range and obtaining the feedwater flow rate value of the feedwater recirculation valve during each level of perturbation; calculating the average and range values ​​of the flow rate values ​​during the period of each level of perturbation after the end of each level of perturbation, and generating flow response feature points corresponding to each level of perturbation based on the average and range values; performing cubic spline interpolation on the flow response feature points corresponding to each level of perturbation to obtain the flow response trajectory; and performing a first-order difference operation on the flow response trajectory to obtain the feedwater flow rate change trajectory.

[0011] In a preferred embodiment, the step of performing cluster analysis on the water flow signal based on the water flow change trajectory and constructing a signal separation topology for the water flow signal based on the analysis results specifically involves: The water flow rate change trajectory is segmented on the time axis to obtain several trajectory segments. Multidimensional time-domain features are extracted for each trajectory segment, including the trajectory segment mean, trajectory segment variance, trajectory segment peak value, trajectory segment valley value, and trajectory segment slope sign sequence. Based on the multidimensional time-domain features of each trajectory segment, the feature distance matrix between any two trajectory segments is calculated. Cluster analysis is performed on the feature distance matrix to obtain the cluster label of each trajectory segment.

[0012] In a preferred embodiment, the step of constructing the signal separation topology of the water flow signal based on the analysis results specifically involves: dividing the signal segments at corresponding time positions in the water flow signal into different categories according to cluster labels, resulting in several category signal segments; extracting the cluster center trajectory of each cluster as the initial trajectory of each category signal segment, resulting in several initial trajectory sets; calculating the dynamic time warping distance between each initial trajectory and the signal segment at the corresponding time position in the water flow signal, and reallocating the signal segment to the category signal segment corresponding to the nearest initial trajectory based on the dynamic time warping distance, resulting in adjusted category signal segments; obtaining the distribution interval of each adjusted category signal segment of the water flow signal on the time axis, and constructing the signal separation topology of the water flow signal based on the distribution interval.

[0013] In a preferred embodiment, the step of identifying the propagation delay phase of the water flow signal based on the signal separation topology and performing delay compensation on the propagation delay phase to obtain the valve position adjustment phase timing sequence specifically involves: extracting the center time of each category signal segment in the water flow signal on the time axis in the signal separation topology, and arranging the center times according to the category coding order of the category signal segments to obtain a category center time sequence; calculating the time difference between adjacent center times in the category center time sequence to obtain a category transition time interval sequence, and extracting the mode of the category transition time interval sequence as the transition time interval; calculating the difference between the first center time in the category center time sequence and the starting time of the valve position oscillation interval to obtain the propagation delay phase; dynamically correcting the propagation delay phase according to the transition time interval to obtain the propagation delay correction amount for each category signal segment; performing a time-domain reverse translation of each category signal segment in the water flow signal based on the propagation delay correction amount to obtain the translated category signal segment; and rearranging the new center times of the translated category signal segments according to the category coding order to obtain the valve position adjustment phase timing sequence.

[0014] In a preferred embodiment, the step of dynamically correcting the propagation delay phase based on the transfer time interval to obtain the propagation delay correction amount for each category of signal segment specifically involves: for each center moment after the first center moment in the category center moment sequence, calculating the time interval between the current center moment and the previous center moment, and performing a difference operation between the time interval and the transfer time interval to obtain the interval deviation amount of the current center moment; accumulating the interval deviation amounts of all center moments before the current center moment to obtain the cumulative deviation amount of the current center moment, and correcting the propagation delay phase based on the cumulative deviation amount to obtain the propagation delay correction amount for the category of signal segment corresponding to the current center moment.

[0015] In a preferred embodiment, the phase misalignment adjustment of the valve opening of the feedwater recirculation valve during the variable speed reduction process based on the valve position adjustment phase timing sequence specifically involves: acquiring the unit load change rate signal of the coal-fired power generation unit during the variable speed reduction process, and determining the start and end times of the variable speed reduction process based on the unit load change rate signal to obtain the variable speed reduction period; acquiring the current valve opening command sequence of the water recirculation valve, and calculating the time deviation between each phase node in the valve position adjustment phase timing sequence and each command node in the current valve opening command sequence within the variable speed reduction period to obtain a node deviation sequence; performing sign discrimination on the node deviation sequence, marking nodes with positive time deviations as phase leading nodes and nodes with negative time deviations as phase lagging nodes; constructing a phase misalignment distribution map based on the distribution of phase leading and phase lagging nodes; and controlling the valve opening of the feedwater recirculation valve during the variable speed reduction process based on the phase misalignment distribution map.

[0016] In a preferred embodiment, controlling the valve opening of the feedwater recirculation valve during the variable speed reduction process based on the phase misalignment distribution map specifically involves: applying a delay compensation amount to the valve opening command of the phase-leading node and an advance compensation amount to the valve opening command of the phase-lagging node based on the phase misalignment distribution map, thereby obtaining a phase-corrected valve opening command sequence; rearranging the phase-corrected valve opening command sequence according to the time axis to form a valve position control output sequence after phase misalignment adjustment; and controlling the valve opening of the feedwater recirculation valve during the variable speed reduction process based on the valve position control output sequence.

[0017] The technical effects and advantages of this invention regarding the wide-load variable-rate cruise control method for supercritical coal-fired power generating units are as follows: This invention acquires the valve position signal and water flow signal of the feedwater recirculation valve in a coal-fired power generating unit, and identifies the valve position oscillation range by combining the valve position change and water flow response characteristics, thereby accurately locating the dynamic abnormal region of the valve during rapid load reduction. Furthermore, it applies valve position perturbation to the feedwater recirculation valve within the valve position oscillation range and extracts the feedwater flow change trajectory after the perturbation, enabling proactive acquisition of the dynamic correlation characteristics between valve position change and feedwater flow response. Based on the feedwater flow change trajectory, it performs cluster analysis on the feedwater flow signal and constructs a signal separation topology to distinguish different flow response states and their temporal evolution relationships. Further utilizing… The signal separation topology identifies the delayed phase during the propagation of the feedwater flow signal and compensates for the propagation delay phase to obtain a valve position adjustment phase sequence that matches the actual flow response. Finally, based on the valve position adjustment phase sequence, the opening of the feedwater recirculation valve during the variable speed reduction process is adjusted by phase misalignment, so that the valve adjustment action can adapt to the dynamic changes in feedwater flow in advance, reducing flow fluctuations and regulation oscillations caused by valve position response lag. This improves the stability of feedwater regulation during the rapid load reduction process of coal-fired power generating units, avoids uncontrolled fluctuations in steam temperature due to steam-water energy imbalance, and improves the safety and reliability of the unit's wide-load variable speed operation. Attached Figure Description

[0018] Figure 1 This is a flowchart illustrating the wide-load variable-rate cruise control method for supercritical coal-fired power generating units according to the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1, Figure 1 This invention presents a wide-load variable-rate cruise control method for supercritical coal-fired power generating units, comprising the following steps: S1, acquire the valve position signal and water flow signal of the feedwater recirculation valve of the coal-fired power generation unit, and identify the valve position oscillation range based on the valve position signal and water flow signal; In this embodiment, the valve position oscillation range is identified based on the valve position signal and the water flow signal, specifically as follows: The valve position signal and water flow signal are subjected to joint time-frequency domain analysis to obtain the dominant fluctuation component of the valve position signal; Extract the amplitude envelope of the dominant fluctuation component, and identify the oscillation start and end times of the valve position signal based on the amplitude envelope to obtain the valve position oscillation period; During the valve position oscillation period, the sliding window variance of the water flow signal is calculated, and the flow fluctuation range of the water flow signal is identified based on the calculation results. The intersection of the valve position oscillation period and the flow fluctuation range on the time axis is extracted to obtain the oscillation coupling range; Calculate the time-domain cross-correlation function of the valve position signal and the water flow signal within the oscillation coupling interval, and calculate the peak phase offset of the cross-correlation function; The oscillation coupling interval is corrected based on the peak phase offset of the cross-correlation function to obtain the valve position oscillation interval.

[0021] It should be noted that the valve position signal of the feedwater recirculation valve is a continuously changing signal characterizing the valve's opening status during operation. It reflects the actual response of the valve actuator to control commands and the degree of valve core opening at various times. During wide-load operation of the unit, with load changes, feedwater regulation, and continuous adjustments to control commands, the valve position signal typically exhibits a continuously changing temporal characteristic. When the valve experiences frequent adjustments, execution lag, or decreased stability, the valve position signal will show periodic fluctuations with a certain regularity. The water flow signal, on the other hand, is continuous temporal data reflecting the actual fluid flow changes within the feedwater recirculation pipeline. It characterizes the change in the medium flow state within the pipeline after valve regulation. Because feedwater flow is affected by factors such as valve opening, hydraulic inertia, pipeline volume, and the medium transport process, the water flow signal typically exhibits a certain response lag compared to the valve position signal, and may be accompanied by amplitude attenuation, fluctuation amplification, or local oscillations.

[0022] Furthermore, the valve position signal and water flow signal are arranged according to a unified time base, maintaining time synchronization between the two types of signals. Based on this, the fluctuation characteristics of the two types of signals over time and the distribution of different frequency components are analyzed. For the valve position signal, the focus is on identifying the duration, energy distribution, and trend of each frequency component throughout the entire operation period. Combined with the frequency response of the water flow signal at the corresponding moment, the frequency ranges with synchronous variation characteristics in the two types of signals are analyzed to eliminate discrete frequency components formed by random disturbances and short-term noise. Subsequently, the stability and energy proportion of each continuous frequency component throughout the entire analysis period are compared. The fluctuation component with the longest duration, the highest energy proportion, and the ability to form a corresponding response relationship in the water flow signal is identified as the dominant fluctuation component of the valve position signal.

[0023] After obtaining the dominant fluctuation component of the valve position signal, the oscillation amplitude changes of this component at each moment are continuously analyzed along the time axis. A continuously changing outer envelope curve is formed based on each local peak value, serving as the amplitude envelope of the dominant fluctuation component. Subsequently, the amplitude envelope is continuously analyzed. When the amplitude envelope rises continuously from a stable state and exceeds the normal operating fluctuation range, the time corresponding to the first entry into a sustained oscillation state is determined as the oscillation start time. During the oscillation process, the changing trend of the amplitude envelope is continuously tracked. When the amplitude envelope gradually falls back and continuously recovers to the normal operating fluctuation range and remains stable, the corresponding time is determined as the oscillation termination time. Finally, the continuous time range between the oscillation start time and the oscillation termination time is used as the valve position oscillation period, ensuring that the identified oscillation period fully covers the continuous oscillation process of the valve position and avoiding misidentification of short-term disturbances or isolated fluctuations as an oscillation state.

[0024] Secondly, using the valve position oscillation period as the analysis range, the water flow signal is segmented sequentially according to continuous time windows. After completing the statistics for each time window, the time window is continuously moved along the time axis. For each time window, the dispersion of the water flow signal relative to the average change level within the window is statistically analyzed, and the fluctuation strength of the corresponding window is obtained accordingly. When multiple consecutive time windows show a large degree of fluctuation and the change trend remains continuous, it is considered that the water flow within that time range is continuously affected by the valve position oscillation; when the fluctuation level in subsequent time windows gradually returns to the normal operating state, it is considered that the flow fluctuation has ended. Finally, the time range in which there is a continuous and obvious fluctuation is determined as the flow fluctuation range of the water flow signal, to reflect the actual fluctuation process of the feedwater flow caused by the valve position oscillation.

[0025] Furthermore, the valve position oscillation period and the flow fluctuation range are mapped to the same time axis for comparison, and the overlap between the two in time range is determined one by one. When the valve position oscillation period and the flow fluctuation range overlap, the continuous time range covered by both is extracted; if there are multiple independent overlapping parts, they are retained separately and arranged in chronological order. When there is only a short time interval between adjacent overlapping intervals and the fluctuations on both sides have a continuous change relationship, the adjacent intervals can be merged into the same continuous segment. Finally, all continuous overlapping time ranges are taken as the oscillation coupling interval, so that the interval simultaneously satisfies the conditions of valve position oscillation and synchronous water flow fluctuation.

[0026] Furthermore, within the oscillation coupling interval, using the valve position signal as the reference sequence and the water flow signal as the sequence to be analyzed, while keeping the time position of the valve position signal unchanged, the water flow signal is shifted forward and backward sequentially. After each time shift, the two sets of signals corresponding to the current time position are compared point-by-point according to the same sampling time. The direction and amplitude of change at the corresponding sampling points are comprehensively compared, and the comparison results of each corresponding sampling point within the entire oscillation coupling interval are accumulated to obtain the correlation value corresponding to the current time offset. The above accumulation process is repeated according to different time offsets, so that each time offset corresponds to a unique correlation value, and the correspondence between the time offset and the correlation value is established, thereby constructing a time-domain cross-correlation function.

[0027] Subsequently, the function point with the largest correlation value is found in the time-domain cross-correlation function, and the time offset corresponding to the function point is extracted. The time offset is used as the response delay when the valve position signal and the water flow signal reach the maximum correlation. Then, according to the oscillation period corresponding to the dominant fluctuation component of the valve position signal, the response delay is converted into the corresponding phase offset to obtain the peak phase offset of the cross-correlation function, which characterizes the actual propagation lag of the water flow signal relative to the valve position signal.

[0028] Finally, the time offset corresponding to the peak phase offset of the cross-correlation function is used as the correction benchmark for the oscillation coupling interval. First, the offset direction corresponding to the peak phase offset is determined. When the peak phase offset corresponds to a lag in the water flow signal relative to the valve position signal, the time position corresponding to the valve position signal is kept unchanged, and the oscillation coupling interval is shifted as a whole along the time axis in the actual response direction of the water flow signal. When the peak phase offset corresponds to a lead in the water flow signal relative to the valve position signal, the oscillation coupling interval is shifted as a whole in the opposite direction. After the overall shift is completed, the corrected oscillation coupling interval is used as the new analysis range. The continuous oscillation segments corresponding to the valve position signal within this time range are re-extracted, and it is determined whether there is a continuous correlation response corresponding to the water flow signal within each oscillation segment. When the time interval between adjacent oscillation segments is less than the preset continuous interval, the adjacent oscillation segments are merged. When there is no continuous response relationship between adjacent oscillation segments, they are retained as independent oscillation segments. Subsequently, the start and end times of each continuous oscillation segment were determined, and the continuous oscillation segments were arranged in chronological order to obtain the corrected valve position oscillation range, so that the obtained valve position oscillation range could be consistent with the actual dynamic response of the water supply flow signal.

[0029] S2, within the valve position oscillation range, the valve position of the feedwater recirculation valve is disturbed, and the trajectory of the feedwater flow rate change after the valve position disturbance is extracted; In this embodiment, the valve position of the feedwater recirculation valve is disturbed within the valve position oscillation range, and the feedwater flow rate change trajectory after the valve position disturbance is extracted, specifically as follows: Within the valve position oscillation range, apply multi-level amplitude disturbance signals to the feedwater recirculation valve and obtain the water flow rate value of the feedwater recirculation valve in each level of disturbance; After each level of disturbance ends, calculate the average and range of water flow during that level of disturbance, and generate flow response characteristic points corresponding to each level of disturbance based on the average and range values. The flow response trajectory is obtained by cubic spline interpolation of the flow response feature points corresponding to each level of disturbance. The flow response trajectory is subjected to a first-order difference operation to obtain the water supply flow change trajectory.

[0030] It should be noted that the valve position oscillation range is used as the implementation range for valve position disturbance, and the unit's operating status and other control parameters are kept untouched. Within the valve position oscillation range, the current valve position of the feedwater recirculation valve is used as the reference opening. Multiple valve position adjustments of different levels are applied sequentially according to the disturbance amplitude, from smallest to largest. Each level of disturbance is maintained for a preset duration, allowing the valve opening to stabilize at the corresponding disturbance level before proceeding to the next level. During each level of disturbance, the change in water flow in the feedwater recirculation pipeline is continuously recorded, and the water flow value at the corresponding moment is obtained at a uniform sampling interval until the current level of disturbance ends. Then, the valve position is restored to the reference position, and the next level of disturbance is applied. After completing all levels of disturbance sequentially, the continuous water flow value corresponding to each level of disturbance can be obtained.

[0031] For each level of disturbance, all water flow values ​​acquired are aggregated according to the corresponding disturbance time range. The overall change level of all water flow values ​​within that time range is statistically analyzed, and the average result of all sampled values ​​is used as the stable flow characteristic under that level of disturbance. Simultaneously, the maximum and minimum water flow values ​​within that time range are extracted, and the range between them is calculated to reflect the degree of fluctuation in water flow under the current disturbance conditions. Subsequently, the average value is used as the center position of the flow response, and the range is used as the representation information of the flow fluctuation amplitude. These two values ​​are then correlated according to the current disturbance level to form a unique flow response feature point corresponding to that level of disturbance. After completing the statistics for all disturbance levels, multiple flow response feature points arranged in order of disturbance amplitude are obtained.

[0032] Furthermore, according to the order in which disturbances at each level are implemented, the corresponding flow response characteristic points are arranged sequentially, and a continuous correspondence between the characteristic points is established based on the disturbance level. Then, using adjacent flow response characteristic points as continuous connection objects, a smooth transition segment is constructed between adjacent characteristic points while ensuring that the positions of each characteristic point remain unchanged. This ensures that the trend of change after connection remains continuous at each characteristic point, and that there are no obvious abrupt changes between adjacent transition segments. After completing the continuous connection between all adjacent characteristic points, each independent transition segment connects end to end to form a continuously changing flow response trajectory.

[0033] Finally, following the direction of change in the flow response trajectory, two consecutive trajectory points are extracted sequentially from adjacent positions, and the change of the latter trajectory point relative to the former is calculated to obtain the flow change corresponding to the current position. Then, moving one trajectory point forward, the calculation of changes between adjacent trajectory points is repeated until the continuous processing of the entire flow response trajectory is completed. For the change results corresponding to all adjacent trajectory points, a new change sequence is reassembled according to the original arrangement, so that each change result corresponds to a local change process in the flow response trajectory. When the change results between adjacent positions continuously increase, it indicates that the water supply flow in that section is continuously increasing; when the change results continuously decrease, it indicates that the water supply flow is gradually decreasing; when the change results approach stability, it indicates that the flow response is tending to stabilize. Ultimately, the water supply flow change trajectory is composed of the change results of all adjacent trajectory points.

[0034] S3, cluster analysis is performed on the water flow rate signal based on the water flow rate change trajectory, and a signal separation topology of the water flow rate signal is constructed based on the analysis results; In this embodiment, cluster analysis is performed on the water flow rate signal based on the water flow rate change trajectory, and a signal separation topology for the water flow rate signal is constructed based on the analysis results, specifically as follows: The water flow rate change trajectory is segmented on the time axis to obtain several trajectory segments, and multidimensional time-domain features are extracted for each trajectory segment. The multidimensional time-domain features include the trajectory segment mean, trajectory segment variance, trajectory segment peak value, trajectory segment valley value, and trajectory segment slope sign sequence. Based on the multidimensional temporal features of each trajectory segment, calculate the feature distance matrix between any two trajectory segments; Cluster analysis is performed on the feature distance matrix to obtain the cluster label for each trajectory segment.

[0035] It should be noted that continuous time segments are sequentially divided along the time axis corresponding to the water flow change trajectory, ensuring that each time segment contains a continuous water flow change trajectory and that adjacent time segments are seamlessly connected, covering the entire change process. When the water flow change is drastic, the time segment length can be appropriately shortened; when the water flow change is relatively stable, the original time segment length is maintained to ensure that each trajectory segment can fully reflect the local change characteristics within the corresponding time range. After completing all segments, statistical analysis is performed on each trajectory segment. The average change level of all change values ​​within the trajectory segment is calculated as the trajectory segment mean; the dispersion of each change value around the average change level is calculated as the trajectory segment variance; the largest change value within the trajectory segment is extracted as the trajectory segment peak value, and the smallest change value is extracted as the trajectory segment valley value; then, according to the increase or decrease relationship between adjacent change values ​​within the trajectory segment, the direction of local change for each segment is determined sequentially, with continuous increases marked as an upward direction and continuous decreases marked as a downward direction, and a trajectory segment slope sign sequence is formed according to the chronological order. Ultimately, each trajectory segment corresponds to a set of trajectory segment mean, trajectory segment variance, trajectory segment peak value, trajectory segment valley value, and trajectory segment slope sign sequence, which together constitute the multidimensional time-domain features of the trajectory segment.

[0036] Furthermore, the multidimensional time-domain features corresponding to each trajectory segment are arranged in a unified order, ensuring that each trajectory segment has a unique corresponding feature description. Then, using one trajectory segment as a reference, it is compared sequentially with the remaining trajectory segments, analyzing the consistency of the trajectory segment mean, variance, peak value, valley value, and slope sign sequence item by item. When the differences between the corresponding features of two trajectory segments are small, their variation patterns are considered similar; when the differences are large, their variation patterns are considered significantly different. After completing the comparison between the reference trajectory segment and all trajectory segments, the above process is repeated using the remaining trajectory segments as new references until a correspondence analysis is completed between any two trajectory segments, and the corresponding feature distance is obtained. Finally, the feature distances between all trajectory segments are arranged according to their trajectory segment numbers, so that each position in the matrix corresponds to the feature distance between two trajectory segments, thus constructing a complete feature distance matrix.

[0037] Finally, using the feature distance matrix as the basis for determining the similarity between trajectory segments, each trajectory segment is first initialized as an independent category. Then, following the order of increasing feature distance, the two categories with the smallest feature distance are merged first, ensuring that trajectory segments with the most similar patterns of change are grouped into the same category. After one category merging, the feature distance between the new category and other categories is recalculated, and the category merging process is repeated according to the principle of minimum feature distance, gradually clustering trajectory segments with similar changing characteristics into larger categories. When the feature distance between categories reaches a preset distinguishing condition, merging stops, and each final category is identified as a cluster. Subsequently, each trajectory segment is assigned a corresponding category label according to its cluster affiliation, so that trajectory segments belonging to the same cluster have the same cluster label, while trajectory segments belonging to different clusters have different cluster labels, thus completing the classification of trajectory segments.

[0038] In this embodiment, a signal separation topology for the water supply flow signal is constructed based on the analysis results, specifically as follows: Based on the cluster labels, the signal segments at corresponding time positions in the water flow signal are divided into different categories, resulting in several categories of signal segments; The cluster center trajectory of each cluster is extracted as the initial trajectory of each category signal segment, resulting in several initial trajectory sets; Calculate the dynamic time warping distance between each initial trajectory and the signal segment at the corresponding time position in the water flow signal, and reallocate the signal segment to the category signal segment corresponding to the nearest initial trajectory based on the dynamic time warping distance to obtain the adjusted category signal segment; The distribution range of each adjusted category signal segment of the water flow signal on the time axis is obtained, and a signal separation topology of the water flow signal is constructed based on the distribution range.

[0039] It should be noted that, based on the cluster label corresponding to each trajectory segment, the temporal position of that trajectory segment in the original water supply flow signal is sequentially located, and the continuous water flow signal segment corresponding to that time position is extracted. Subsequently, all signal segments with the same cluster label are grouped into the same category, while signal segments with different cluster labels are grouped into different categories, thus reclassifying the original water supply flow signal into multiple categories according to its variation characteristics. For multiple signal segments distributed at different time positions within the same category, their original positions on the time axis are kept unchanged; only the correspondence between their respective categories is established, without altering the temporal structure of the signal itself. After classifying all signal segments, each category contains several signal segments with similar variation patterns, resulting in several categories of signal segments.

[0040] Furthermore, for each cluster, all signal segments belonging to that cluster are arranged chronologically, and the overall change trends among the signal segments are compared one by one. When a signal segment of a certain category maintains high consistency with other signal segments of the same category within the same cluster, and its overall change process can represent the change pattern of most signal segments within that cluster, then the change trajectory corresponding to that category of signal segment is determined as the cluster center trajectory of that cluster. Subsequently, the cluster center trajectory is used as the initial trajectory of the corresponding category of signal segment and saved according to the cluster number, so that each cluster corresponds to a unique initial trajectory. After all clusters have been processed, the initial trajectories corresponding to each cluster together form several initial trajectory sets.

[0041] Secondly, using each initial trajectory as a reference, it is compared one by one with each signal segment at the corresponding time position in the water supply flow signal. During the comparison, the overall change order of the two trajectories remains unchanged, and the time position of segments with different local change rates is adjusted to gradually establish a correspondence between positions with similar change trends in the two trajectories. The dynamic time warping distance between the current signal segment and the initial trajectory is obtained based on the overall difference between all corresponding positions. Subsequently, the same signal segment is analyzed in correspondence with all initial trajectories, and the magnitude of each dynamic time warping distance is compared. The initial trajectory with the smallest dynamic time warping distance is determined as the closest change type for that signal segment, and the signal segment is reclassified into the category corresponding to that initial trajectory.

[0042] Finally, the start and end times of each adjusted category signal segment in the original water supply flow signal are extracted, and the distribution range of each category signal segment on the entire time axis is determined based on its corresponding time position. Subsequently, all category signal segments are arranged in chronological order, and the connection relationship between adjacent category signal segments is established one by one, recording the positions of transitions between different categories and their corresponding chronological relationships. When the same category signal segment appears repeatedly at multiple time positions, their mutual correspondence is established to characterize the repeated distribution characteristics of the same change type in different time ranges; when different category signal segments appear consecutively, the transition relationship between different categories is established to reflect the evolution process between different change states during water supply flow changes. After establishing the correspondence between all category signal segments, each category signal segment is used as a topology node, and the time connection relationship, repeated correspondence relationship, and category transition relationship between each node are used as topology connection relationships to jointly construct the signal separation topology of the water supply flow signal. This signal separation topology not only reflects the distribution position of various flow change characteristics but also characterizes the evolution relationship between different flow change states, providing a temporal topological basis for subsequent propagation delay phase identification.

[0043] S4. Based on the signal separation topology, the propagation delay phase of the water flow signal is identified, and the propagation delay phase is compensated for to obtain the valve position adjustment phase timing. In this embodiment, the propagation delay phase of the water flow signal is identified based on the signal separation topology, and delay compensation is performed on the propagation delay phase to obtain the valve position adjustment phase timing, specifically: The center time of each category signal segment in the water supply flow signal is extracted on the time axis in the signal separation topology, and the center times are arranged according to the category coding order of the category signal segments to obtain the category center time sequence; Calculate the time difference between adjacent center times in the category center time sequence to obtain the category transition time interval sequence, and extract the mode of the category transition time interval sequence as the transition time interval; The propagation delay phase is obtained by calculating the difference between the first center time in the category center time sequence and the starting time of the valve position oscillation interval; The propagation delay phase is dynamically corrected based on the transfer time interval to obtain the propagation delay correction amount for each type of signal segment; Based on the propagation delay correction, each category of signal segment in the water supply flow signal is time-domain reverse-shifted to obtain the shifted category of signal segment. The new center times of the shifted category signal segments are rearranged according to the category coding order to obtain the valve position adjustment phase timing.

[0044] It should be noted that after constructing the signal separation topology, each category of signal segment in the topology is traversed sequentially. The start and end times of each category of signal segment are read on the time axis, and the midpoint between the start and end times is determined. The time corresponding to this midpoint is taken as the center time of that category of signal segment. After extracting the center times of all categories of signal segments, they are sorted according to their category codes. For multiple categories of signal segments with the same category code, they are arranged according to their chronological order on the time axis; for categories of signal segments with different category codes, they are arranged in ascending order of category code. Finally, all the arranged center times are sequentially assembled into a category center time sequence, which reflects both the category relationship of each category of signal segment and maintains the chronological order within the same category.

[0045] Furthermore, following the order of the category center time sequence, adjacent center times are selected sequentially, and the time interval corresponding to the latter center time relative to the former center time is calculated. These time intervals are then recorded in the original order. After one calculation, the next set of adjacent center times is selected, and the same process is repeated until all adjacent center times in the category center time sequence have been statistically analyzed. Subsequently, all time intervals are categorized and statistically analyzed according to their numerical values. Time intervals with minor differences but belonging to the same range of variation are grouped into the same statistical interval for accumulation, and the frequency of occurrence for each time interval is counted. The time interval with the highest frequency is identified as the most common transition rule between categories and is used as the transition time interval.

[0046] Furthermore, the first center time is extracted from the categorical center time sequence, and the start time of the corresponding valve position oscillation interval is read. Using the start time of the valve position oscillation interval as a time reference position, the time interval between the first center time and this reference position is statistically analyzed. If the first center time is after the start time of the valve position oscillation interval, it is considered that the change in feedwater flow rate has a response lag relative to the valve position oscillation; if the first center time is before the start time of the valve position oscillation interval, it is considered that the change in feedwater flow rate has an early response. Subsequently, the time difference between the two is used as the initial time amount for the response offset of the feedwater flow rate signal relative to the valve position oscillation. Combined with the time correspondence of signal propagation during valve position oscillation, this time difference is used as the propagation delay phase to represent the overall propagation delay generated during the transmission of valve position action to the change in feedwater flow rate.

[0047] Furthermore, using the propagation delay phase as the initial correction benchmark, the actual transition between signal segments of each category is analyzed sequentially according to the arrangement of the category center time sequence. First, the actual time interval between adjacent category center times is calculated and compared one by one with the pre-obtained transition time interval to determine the degree of deviation of each category transition relative to the typical transition rhythm. Then, the deviations generated during each transition are gradually accumulated according to the chronological order of the category center times, allowing the propagation delay phase to be dynamically adjusted during the category transition process. Once the accumulated deviation for a certain category of signal segment is determined, this accumulated deviation is added to the propagation delay phase to correct the propagation delay phase, obtaining the propagation delay correction amount for that category of signal segment. After completing the dynamic correction of all category signal segments sequentially, each category of signal segment corresponds to a propagation delay correction amount that reflects its actual propagation delay state, thus avoiding the problem of gradual accumulation of correction errors between different categories caused by using a fixed propagation delay.

[0048] Furthermore, for each category of signal segment, the corresponding propagation delay correction value is read, and this value is used as the basis for time correction to adjust the position of that category of signal segment on the time axis. When the propagation delay correction value corresponds to a lag in the water flow signal, the entire category of signal segment is shifted forward by the corresponding time length along the time axis; when the propagation delay correction value corresponds to an early response in the water flow signal, the entire category of signal segment is shifted backward by the corresponding time length along the time axis. During the translation process, only the start and end positions of the category of signal segment on the time axis are adjusted, maintaining the relative time relationship and change characteristics between the sampling points within the category of signal segment, thus completing the time position correction of the entire category of signal segment. After completing the time adjustment of all category of signal segments in sequence, a translated category of signal segment with higher time consistency with the valve position adjustment process is obtained.

[0049] Finally, the start and end times of each translated category signal segment on the time axis are reread, and the center time corresponding to each category signal segment is redefined so that the new center time reflects the actual time position of the category signal segment after propagation delay compensation. Subsequently, the signal segments are reordered according to their category codes. For category signal segments with the same category code, they are still arranged according to the order of their new center times on the time axis; for category signal segments with different category codes, they are arranged sequentially according to their category codes, maintaining the sequential correspondence between categories. After reordering all category signal segments, the new center times are sequentially connected to form a continuous time series. This time series is used as the valve position adjustment phase sequence, enabling the valve position adjustment action to be controlled according to the actual response sequence after propagation delay compensation, thereby improving the adjustment coordination of the feedwater recirculation valve during the variable speed reduction process.

[0050] In this embodiment, the propagation delay phase is dynamically corrected based on the transfer time interval to obtain the propagation delay correction amount for each type of signal segment, specifically: For each center time after the first center time in the category center time sequence, calculate the time interval between the current center time and the previous center time, and perform a difference operation between the time interval and the transition time interval to obtain the interval deviation of the current center time. The interval deviations of all center times before the current center time are accumulated to obtain the cumulative deviation of the current center time. The propagation delay phase is then corrected based on the cumulative deviation to obtain the propagation delay correction amount for the corresponding category of signal segment at the current center time.

[0051] It should be noted that in the category center time sequence, the first center time is used as the initial reference point, and processing is performed sequentially starting from the second center time. For the current center time, its corresponding time position and the time position corresponding to the previous center time are read, and the actual time length between the two is calculated. This time length is taken as the actual time interval corresponding to the current category transition. Subsequently, the actual time interval is compared with the predetermined transition time interval to determine the change of the current category transition process relative to the typical transition rhythm. When the actual time interval is greater than the transition time interval, the current category transition is considered to be delayed, and the corresponding delay deviation is recorded; when the actual time interval is less than the transition time interval, the current category transition is considered to be advanced, and the corresponding advance deviation is recorded; when the two are basically the same, the current category transition is considered to be maintaining a normal rhythm, and the corresponding deviation is recorded as zero or close to zero. After completing the statistics of the current center time, the remaining center times are processed sequentially according to the category center time sequence until all category center times have been analyzed, thereby obtaining the interval deviation corresponding to each center time.

[0052] Secondly, following the sequence of category center times, the first center time is used as the starting point for cumulative calculation. Starting from the second center time, all interval deviations corresponding to each category transition before the current center time are read sequentially and accumulated item by item according to the order in which the category transitions occur. This ensures that the time offsets generated during the previous category transitions are gradually propagated to the current category transition position. After accumulation, the result is used as the cumulative deviation at the current center time, representing the overall time offset accumulated by the current category signal segment relative to the initial propagation delay. Subsequently, the cumulative deviation at the current center time is corrected in relation to the propagation delay phase. When the cumulative deviation indicates that the propagation delay is gradually increasing, the propagation delay of the current category signal segment is increased accordingly; when the cumulative deviation indicates that the propagation delay is gradually decreasing, the propagation delay of the current category signal segment is decreased accordingly; when the cumulative deviation remains stable, the propagation delay phase is kept unchanged. After the correction is completed, the propagation delay correction amount of the signal segment corresponding to the current center time is obtained, and the same process is repeated for subsequent center times, so that each signal segment of the category can obtain a propagation delay correction amount that can reflect the cumulative effect of the previous category conversion, thereby ensuring that the propagation delay compensation can be continuously adjusted with the category conversion process, rather than always using a fixed delay value.

[0053] S5, based on the valve position adjustment phase timing, adjusts the valve position opening of the water supply recirculation valve during the variable speed reduction process by phase misalignment.

[0054] In this embodiment, the valve opening of the feedwater recirculation valve is adjusted by phase misalignment during the variable speed reduction process based on the valve position adjustment phase timing sequence, specifically as follows: The load change rate signal of the coal-fired power generating unit during the speed reduction process is obtained, and the start and end times of the speed reduction process are determined based on the load change rate signal to obtain the speed reduction period. Obtain the current valve position opening command sequence of the water recirculation valve, and calculate the time deviation between each phase node in the valve position adjustment phase timing sequence and each command node in the current valve position opening command sequence during the variable speed reduction period to obtain the node deviation sequence; The node deviation sequence is marked with a sign, and nodes with positive time deviations are marked as phase-leading nodes, while nodes with negative time deviations are marked as phase-lagging nodes. A phase misalignment distribution map is constructed based on the distribution of phase-leading and phase-lagging nodes; The valve opening of the water supply recirculation valve during the variable speed reduction process is controlled based on the phase misalignment distribution map.

[0055] It should be noted that during the variable-speed reduction operation of the coal-fired power generating unit, the load change rate signal over time is continuously acquired. This signal reflects the rate of decrease or change in the unit load per unit time. The acquired load change rate signals are analyzed chronologically to determine the load change state at each moment. When the load change rate changes from a stable operating state to a continuously decreasing state, and remains above the normal fluctuation range for multiple consecutive sampling moments, the time when this state begins to appear is determined as the start time of the variable-speed reduction process. Subsequently, the changes in the load change rate signal are continuously tracked. When the load change rate gradually returns to the stable operating range, and the unit load no longer maintains a continuous decreasing trend, the corresponding time is determined as the end time of the variable-speed reduction process. The continuous time range between the start and end times is defined as the variable-speed reduction period, ensuring that subsequent valve position phase misalignment analysis is performed only on the effective adjustment phase during the unit load change process.

[0056] Further, after determining the variable speed reduction period, the valve position opening control commands actually received by the feedwater recirculation valve within this time range are extracted and arranged according to the order in which the commands were generated, forming the current valve position opening command sequence. Simultaneously, the time position corresponding to each phase node in the valve position adjustment phase sequence is read, and each phase node is matched with the control node in the valve position opening command sequence. For each phase node, its corresponding valve position control command node is found, and their sequential relationship on the time axis is compared to determine the actual time offset of the phase node relative to the current valve position opening command. When the phase node appears before the corresponding control command, it indicates that the adjustment process has an early change; when the phase node appears after the corresponding control command, it indicates that the adjustment process has a delayed change. After sequentially completing the time comparison between all phase nodes and control command nodes, the time offset results corresponding to each node are combined according to the phase node arrangement order to obtain a node deviation sequence, which is used to describe the time misalignment relationship between the valve position adjustment phase and the actual control command.

[0057] Furthermore, the direction of each node deviation value in the node deviation sequence is determined sequentially, and its phase state is determined based on the time sequence corresponding to the node deviation value. When the time deviation of a node indicates that the valve position adjustment phase node is ahead of the current valve position opening command node, the node is marked as a phase-leading node, indicating that the valve position adjustment action at that position occurs ahead of schedule. When the time deviation of a node indicates that the valve position adjustment phase node is behind the current valve position opening command node, the node is marked as a phase-lagging node, indicating that the valve position adjustment action at that position fails to keep up with the control command change in a timely manner. For nodes with a time deviation close to zero, their phase matching degree is considered to be high, and they can be retained as normal synchronization nodes. After completing the sign determination of all nodes, each node in the node deviation sequence has a clear phase state identifier, thereby distinguishing the phase advance or phase lag at different positions during the speed reduction process.

[0058] Finally, after determining the sign of the node deviation sequence, all phase-leading and phase-lag nodes are arranged according to their corresponding time positions and the valve position adjustment phase node sequence, and the distribution range of each type of node during the speed reduction period is extracted. When multiple phase-leading nodes appear consecutively in a certain time region, the region is marked as a phase-leading concentrated region; when multiple phase-lag nodes appear consecutively in another time region, the region is marked as a phase-lag concentrated region. Simultaneously, the transition positions and durations between nodes of different misalignment types are recorded to reflect the change process of phase misalignment state during valve position adjustment. Subsequently, using the speed reduction period as the time reference and the phase node positions as adjustment state identifiers, the phase-leading region, phase-lag region, and normal matching region are associated and arranged in chronological order to form a phase misalignment distribution map. This phase misalignment distribution map can intuitively reflect the advance, lag, and change trend of the valve position adjustment phase relative to the control command at different time positions, providing a basis for subsequent valve position opening phase misalignment adjustment.

[0059] In this embodiment, the valve opening of the water recirculation valve during the variable speed reduction process is controlled based on the phase misalignment distribution map, specifically as follows: Based on the phase misalignment distribution map, a delay compensation amount is applied to the valve position opening command of the phase leading node, and an advance compensation amount is applied to the valve position opening command of the phase lagging node, so as to obtain the valve position opening command sequence after phase correction. The phase-corrected valve position opening command sequence is rearranged according to the time axis to form the valve position control output sequence after phase misalignment adjustment. The valve position opening of the water supply recirculation valve during the variable speed reduction process is controlled based on the valve position control output sequence.

[0060] It should be noted that, based on the phase state corresponding to each node in the phase misalignment distribution map, the time position and corresponding time offset of the phase-leading and phase-lag nodes during the speed reduction process are obtained respectively. For valve position opening commands marked as phase-leading nodes, since the valve position adjustment action corresponding to this node occurs before the actual demand change, the corresponding delay compensation amount is determined according to the phase lead degree corresponding to this node, and the execution time of the original valve position opening command is adjusted backward to match the valve position adjustment action with the actual response process of the feedwater flow. For valve position opening commands marked as phase-lag nodes, since the valve position adjustment action corresponding to this node occurs after the actual demand change, the corresponding advance compensation amount is determined according to the phase lag degree corresponding to this node, and the execution time of the original valve position opening command is adjusted forward to enable the valve position adjustment process to respond to unit load changes in advance. After completing the time correction of all phase nodes, the original opening trend of the valve position opening command is kept unchanged. Only the execution time of each control node is adjusted to obtain the valve position opening command sequence after phase correction, so that the valve position adjustment process can eliminate the phase misalignment caused by propagation delay and dynamic response difference.

[0061] Furthermore, after completing the phase correction of each valve position opening command node, the corrected time position of each control node is reread and sorted according to the corrected time sequence. For valve position opening command nodes whose original time positions have changed, they are re-inserted into their corresponding time positions according to their new execution times; for control nodes whose time positions have not been adjusted, their original arrangement remains unchanged. During the rearrangement process, adjacent control nodes are connected according to time continuity, so that the phase-corrected valve position opening commands can be output continuously according to the new execution order, avoiding the disorder of control command sequence caused by node time adjustments. After all control nodes are reordered, the sorted valve position opening commands are combined according to the time axis sequence to form a valve position control output sequence after phase misalignment adjustment, so that this output sequence can reflect the actual adjustment requirements after propagation delay compensation and phase correction.

[0062] Finally, the valve position control output sequence after phase misalignment adjustment is used as the basis for valve position adjustment of the feedwater recirculation valve during the variable speed reduction process. Valve position opening adjustments are executed sequentially according to the time order corresponding to each control node in the output sequence. When the execution time corresponding to a certain control node is reached, the valve position opening command corresponding to that node is sent to the feedwater recirculation valve, causing the valve opening to adjust according to the change pattern after phase correction. During the valve position adjustment process, the time correspondence between the valve position opening change and the unit load reduction process is continuously maintained, enabling the feedwater recirculation valve to avoid premature or delayed adjustment due to flow response lag. After all control nodes are executed, a valve position phase misalignment adjustment during the variable speed reduction process is completed, allowing the actual adjustment process of the feedwater recirculation valve to better match the feedwater flow rate change process, improving the stability of valve position adjustment during wide-load variable speed operation.

[0063] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, in the form of a computer program product.

[0064] Those skilled in the art will recognize that the modules and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0065] In addition, the functional modules in the various embodiments of this application can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module.

[0066] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0067] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A wide-load variable-rate cruise control method for supercritical coal-fired power generating units, characterized in that, Includes the following steps: The valve position signal and water flow signal of the feedwater recirculation valve of the coal-fired power generation unit are acquired, and the valve position oscillation range is identified based on the valve position signal and water flow signal. Within the valve position oscillation range, the valve position of the feedwater recirculation valve is disturbed, and the trajectory of the feedwater flow rate change after the valve position disturbance is extracted. Cluster analysis of the water flow rate signal is performed based on the water flow rate change trajectory, and a signal separation topology of the water flow rate signal is constructed based on the analysis results; Based on the signal separation topology, the propagation delay phase of the water flow signal is identified, and the propagation delay phase is compensated to obtain the valve position adjustment phase timing. The valve position opening of the water supply recirculation valve is adjusted by phase misalignment based on the valve position adjustment phase timing.

2. The wide-load variable-rate cruise control method for supercritical coal-fired power generating units according to claim 1, characterized in that, The method of identifying the valve position oscillation range based on valve position signal and water flow signal is as follows: The valve position signal and water flow signal are subjected to joint time-frequency domain analysis to obtain the dominant fluctuation component of the valve position signal; Extract the amplitude envelope of the dominant fluctuation component, and identify the oscillation start and end times of the valve position signal based on the amplitude envelope to obtain the valve position oscillation period; During the valve position oscillation period, the sliding window variance of the water flow signal is calculated, and the flow fluctuation range of the water flow signal is identified based on the calculation results. The intersection of the valve position oscillation period and the flow fluctuation range on the time axis is extracted to obtain the oscillation coupling range; Calculate the time-domain cross-correlation function of the valve position signal and the water flow signal within the oscillation coupling interval, and calculate the peak phase offset of the cross-correlation function; The oscillation coupling interval is corrected based on the peak phase offset of the cross-correlation function to obtain the valve position oscillation interval.

3. The wide-load variable-rate cruise control method for supercritical coal-fired power generating units according to claim 2, characterized in that, The process of perturbing the feedwater recirculation valve within the valve position oscillation range and extracting the feedwater flow rate change trajectory after the valve position perturbed is specifically as follows: Within the valve position oscillation range, apply multi-level amplitude disturbance signals to the feedwater recirculation valve and obtain the water flow rate value of the feedwater recirculation valve in each level of disturbance; After each level of disturbance ends, calculate the average and range of water flow during that level of disturbance, and generate flow response characteristic points corresponding to each level of disturbance based on the average and range values. The flow response trajectory is obtained by cubic spline interpolation of the flow response feature points corresponding to each level of disturbance. The flow response trajectory is subjected to a first-order difference operation to obtain the water supply flow change trajectory.

4. The wide-load variable-rate cruise control method for supercritical coal-fired power generating units according to claim 3, characterized in that, The method of clustering the water flow signal based on the water flow change trajectory and constructing a signal separation topology for the water flow signal based on the analysis results is as follows: The water flow rate change trajectory is segmented on the time axis to obtain several trajectory segments, and multidimensional time-domain features are extracted for each trajectory segment. The multidimensional time-domain features include the trajectory segment mean, trajectory segment variance, trajectory segment peak value, trajectory segment valley value, and trajectory segment slope sign sequence. Based on the multidimensional temporal features of each trajectory segment, calculate the feature distance matrix between any two trajectory segments; Cluster analysis is performed on the feature distance matrix to obtain the cluster label for each trajectory segment.

5. The wide-load variable-rate cruise control method for supercritical coal-fired power generating units according to claim 4, characterized in that, The signal separation topology for constructing the water supply flow signal based on the analysis results is as follows: Based on the cluster labels, the signal segments at corresponding time positions in the water flow signal are divided into different categories, resulting in several categories of signal segments; The cluster center trajectory of each cluster is extracted as the initial trajectory of each category signal segment, resulting in several initial trajectory sets; Calculate the dynamic time warping distance between each initial trajectory and the signal segment at the corresponding time position in the water flow signal, and reallocate the signal segment to the category signal segment corresponding to the nearest initial trajectory based on the dynamic time warping distance to obtain the adjusted category signal segment; The distribution range of each adjusted category signal segment of the water flow signal on the time axis is obtained, and a signal separation topology of the water flow signal is constructed based on the distribution range.

6. The wide-load variable-rate cruise control method for supercritical coal-fired power generating units according to claim 5, characterized in that, The method of identifying the propagation delay phase of the water flow signal based on signal separation topology and compensating for the propagation delay phase to obtain the valve position adjustment phase timing is as follows: The center time of each category signal segment in the water supply flow signal is extracted on the time axis in the signal separation topology, and the center times are arranged according to the category coding order of the category signal segments to obtain the category center time sequence; Calculate the time difference between adjacent center times in the category center time sequence to obtain the category transition time interval sequence, and extract the mode of the category transition time interval sequence as the transition time interval; The propagation delay phase is obtained by calculating the difference between the first center time in the category center time sequence and the starting time of the valve position oscillation interval; The propagation delay phase is dynamically corrected based on the transfer time interval to obtain the propagation delay correction amount for each type of signal segment; Based on the propagation delay correction, each category of signal segment in the water supply flow signal is time-domain reverse-shifted to obtain the shifted category of signal segment. The new center times of the shifted category signal segments are rearranged according to the category coding order to obtain the valve position adjustment phase timing.

7. The wide-load variable-rate cruise control method for supercritical coal-fired power generating units according to claim 6, characterized in that, The dynamic correction of the propagation delay phase based on the transfer time interval to obtain the propagation delay correction amount for each type of signal segment is as follows: For each center time after the first center time in the category center time sequence, calculate the time interval between the current center time and the previous center time, and perform a difference operation between the time interval and the transition time interval to obtain the interval deviation of the current center time. The interval deviations of all center times before the current center time are accumulated to obtain the cumulative deviation of the current center time. The propagation delay phase is then corrected based on the cumulative deviation to obtain the propagation delay correction amount for the corresponding category of signal segment at the current center time.

8. The wide-load variable-rate cruise control method for supercritical coal-fired power generating units according to claim 7, characterized in that, The phase misalignment adjustment of the valve opening of the feedwater recirculation valve during the variable speed reduction process based on the valve position adjustment phase timing is specifically as follows: The load change rate signal of the coal-fired power generating unit during the speed reduction process is obtained, and the start and end times of the speed reduction process are determined based on the load change rate signal to obtain the speed reduction period. Obtain the current valve position opening command sequence of the water recirculation valve, and calculate the time deviation between each phase node in the valve position adjustment phase timing sequence and each command node in the current valve position opening command sequence during the variable speed reduction period to obtain the node deviation sequence; The node deviation sequence is marked with a sign, and nodes with positive time deviations are marked as phase-leading nodes, while nodes with negative time deviations are marked as phase-lagging nodes. A phase misalignment distribution map is constructed based on the distribution of phase-leading and phase-lagging nodes; The valve opening of the water supply recirculation valve during the variable speed reduction process is controlled based on the phase misalignment distribution map.

9. The wide-load variable-rate cruise control method for supercritical coal-fired power generating units according to claim 8, characterized in that, The valve opening degree of the feedwater recirculation valve during the variable speed reduction process, based on the phase misalignment distribution map, is specifically as follows: Based on the phase misalignment distribution map, a delay compensation amount is applied to the valve position opening command of the phase leading node, and an advance compensation amount is applied to the valve position opening command of the phase lagging node, so as to obtain the valve position opening command sequence after phase correction. The phase-corrected valve position opening command sequence is rearranged according to the time axis to form the valve position control output sequence after phase misalignment adjustment. The valve position opening of the water supply recirculation valve during the variable speed reduction process is controlled based on the valve position control output sequence.

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