An Alkali Concentration and Flow Rate Control System and Method Based on Adaptive PID

Abstract

This application relates to the technical field of automatic control, and discloses an adaptive PID-based alkaline solution concentration and flow rate regulation system and method. The system includes a data acquisition module for acquiring the alkaline solution concentration at each circulation node; a data processing module for constructing a concentration sequence for each circulation node based on the alkaline solution concentration; a concentration analysis module for calculating the response characteristic index of the alkaline solution concentration based on the concentration sequence of each circulation node; a control strategy module for identifying concentration response anomalies based on the response characteristic index of the alkaline solution concentration and matching corresponding flow control strategies based on the type of concentration response anomaly; and a flow rate regulation module for real-time regulation of the circulating flow rate of the alkaline solution based on the flow control strategy. This application improves the stability and accuracy of alkaline solution concentration regulation by identifying different abnormal states and performing targeted circulating flow rate adjustments.

Description

Technical Field

[0001] This application relates to the technical field of automation control, specifically to an alkaline solution concentration and flow rate regulation system and method based on adaptive PID. Background Technology

[0002] In an alkaline water electrolysis hydrogen production system, the alkaline solution forms a multi-node, multi-path circulating flow network among the electrolyzer group, storage section, and gas-liquid separation unit. The concentration of the alkaline solution continuously evolves within this network through flow transfer, mixing, and local replenishment, and its spatial distribution is influenced by changes in circulation flow rate, path structure, and electrolysis load.

[0003] Existing control methods typically use the concentration at the main pipe or a single point as the control target, maintaining the concentration near the set value by adjusting the replenishment volume or circulation flow. However, since the system is essentially a multi-volume unit coupled network, when an early imbalance occurs in the concentration distribution between different nodes, the overall concentration is still within the normal range. If timely intervention and regulation are not implemented, the early imbalance in the concentration distribution will continue to worsen, leading to an irreversible imbalance in the system state by the time an abnormality in the main pipe concentration is detected, making it difficult to quickly repair using conventional PID control.

[0004] The information disclosed in this background section is intended only to enhance the understanding of the overall background of this application and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0005] The technical problem to be solved by this application is to overcome the defects of the prior art and provide an alkaline solution concentration and flow rate regulation system and method based on adaptive PID, so as to improve the stability and accuracy of alkaline solution concentration regulation.

[0006] To solve the above-mentioned technical problems, this application provides the following technical solution:

[0007] On one hand, this application provides an adaptive PID-based alkaline solution concentration and flow rate regulation system, including a data acquisition module, a data processing module, a concentration analysis module, a control strategy module, and a flow rate regulation module; wherein:

[0008] The data acquisition module is used to collect the alkali concentration at each cycle node;

[0009] The data processing module constructs a concentration sequence for each loop node based on the alkali concentration.

[0010] The concentration analysis module calculates the response characteristic index of the alkali concentration based on the concentration sequence of each loop node;

[0011] The control strategy module identifies concentration response anomalies based on the response characteristic indicators of alkali concentration, and matches the corresponding flow control strategy based on the type of concentration response anomaly.

[0012] The flow regulation module adjusts the circulating flow rate of the alkali solution in real time based on the flow control strategy.

[0013] As a preferred embodiment of the adaptive PID-based alkali concentration and flow rate regulation system described in this application, the data acquisition module includes a concentration acquisition unit; the concentration acquisition unit is equipped with a concentration detection device installed at each circulation node, and a continuous sampling period is preset; at the beginning of each sampling period, the concentration acquisition unit simultaneously acquires the alkali concentration at each circulation node.

[0014] The circulation node includes a liquid supply input node, an electrolysis output node, a separation reflux node, and a replenishment and mixing node;

[0015] The data processing module includes a data processing unit; the data processing unit processes the alkali concentration into a concentration sequence for each cycle node; the concentration sequence of any cycle node is a time series of the alkali concentration of the corresponding node, including the alkali concentration of the corresponding cycle node in multiple consecutive sampling cycles.

[0016] As a preferred embodiment of the adaptive PID-based alkaline solution concentration and flow rate regulation system described in this application, the concentration analysis module includes a first analysis unit; the response characteristic index includes the concentration change rate of each cycle node in each sampling period.

[0017] The first analysis unit calculates the concentration change rate of each cycle node in each sampling period based on the concentration sequence of each cycle node. For any cycle node, the concentration change rate in any sampling period is the ratio of the concentration change to the length of the sampling period, and the concentration change in any sampling period is the difference between the alkali concentration of the corresponding sampling period and the alkali concentration of the adjacent previous sampling period.

[0018] As a preferred embodiment of the adaptive PID-based alkaline solution concentration and flow rate regulation system described in this application, the concentration analysis module further includes a second analysis unit; the response characteristic index further includes the node concentration difference and concentration gradient identifier between different cycle nodes within any sampling period.

[0019] The second analysis unit calculates the node concentration difference and concentration gradient identifier for each sampling period based on the concentration sequence of each cycle node; the node concentration difference includes the electrolysis concentration difference, the separation concentration difference, and the replenishment concentration difference;

[0020] For any sampling period, the second analysis unit calculates the corresponding nodal concentration difference, specifically including:

[0021] The difference between the alkali concentration at the electrolysis output node and the alkali concentration at the liquid supply input node is calculated as the electrolysis concentration difference for the corresponding sampling period.

[0022] The difference between the alkali concentration at the separation reflux node and the alkali concentration at the electrolysis output node is calculated as the separation concentration difference for the corresponding sampling period.

[0023] The difference between the alkali concentration at the replenishment mixing node and the alkali concentration at the separation reflux node is calculated as the replenishment concentration difference for the corresponding sampling period.

[0024] As a preferred embodiment of the alkaline solution concentration and flow rate regulation system based on adaptive PID described in this application, wherein: the concentration gradient identifier includes a first gradient identifier, a second gradient identifier, and a third gradient identifier;

[0025] For any sampling period, the second analysis unit calculates the concentration gradient identifier based on the corresponding node concentration difference, specifically including:

[0026] If the electrolysis concentration difference is greater than 0, the first gradient indicator is set to 1; otherwise, the first gradient indicator is set to -1.

[0027] If the concentration difference is greater than 0, the second gradient indicator is set to 1; otherwise, the second gradient indicator is set to -1.

[0028] If the concentration difference of the replenishing solution is less than 0, the value of the third gradient indicator is 1; otherwise, the value of the third gradient indicator is -1.

[0029] As a preferred embodiment of the adaptive PID-based alkaline solution concentration and flow rate regulation system described in this application, the control strategy module includes an anomaly detection unit; the anomaly detection unit is configured with an anomaly detection strategy for identifying concentration response anomalies; the concentration response anomalies include concentration gradient anomalies and propagation path anomalies.

[0030] The anomaly detection strategy includes: for any sampling period, if at least one of the first gradient identifier, the second gradient identifier, and the third gradient identifier is -1, then there is a concentration gradient anomaly.

[0031] The anomaly detection strategy further includes: for any sampling period, detecting whether the propagation path conditions are met; if at least one propagation path condition is not met, then there is a propagation path anomaly.

[0032] The propagation path conditions include: the concentration change rate at the liquid mixing node is greater than the concentration change rate at the liquid supply input node; the concentration change rate at the liquid supply input node is greater than the concentration change rate at the electrolysis output node; and the concentration change rate at the electrolysis output node is greater than the concentration change rate at the separation reflux node.

[0033] As a preferred embodiment of the adaptive PID-based alkaline solution concentration and flow rate regulation system described in this application, the control strategy module further includes a strategy matching unit; the strategy matching unit is configured with a PID control strategy; the PID control strategy includes a basic PID strategy, a first control strategy, and a second control strategy.

[0034] Any PID control strategy is used to specify the input error and control output of the PID controller; wherein, in each PID control strategy, the control output of the PID controller is the flow regulation of the circulating flow.

[0035] The strategy matching unit matches the corresponding PID control strategy based on the type of concentration response anomaly and sends it to the flow regulation module; specifically including:

[0036] If an anomaly in the concentration gradient exists, the first control strategy is applied; if no anomaly in the concentration gradient exists, but an anomaly in the propagation path exists, the second control strategy is applied.

[0037] As a preferred embodiment of the adaptive PID-based alkali concentration and flow rate regulation system described in this application, the basic PID strategy includes: setting a target alkali concentration; calculating the difference between the target alkali concentration and the alkali concentration at the supply input node as the input error of the PID controller;

[0038] The first control strategy includes: marking sampling periods without abnormal concentration response as normal periods; and for any node concentration difference, calculating its average value in all normal periods as a reference concentration difference for the node concentration difference.

[0039] Mark the node concentration difference corresponding to any concentration gradient with a value of -1 as an abnormal concentration difference;

[0040] The input error of the PID controller is calculated based on the difference between each abnormal concentration and the corresponding reference concentration.

[0041] As a preferred embodiment of the adaptive PID-based alkali concentration and flow rate regulation system described in this application, the second control strategy includes: calculating the node concentration rate difference, including a first rate difference, a second rate difference, and a third rate difference; wherein, the first rate difference is the difference between the concentration change rate of the replenishment mixing node and the concentration change rate of the supply input node; the second rate difference is the difference between the concentration change rate of the supply input node and the concentration change rate of the electrolysis output node; and the third rate difference is the difference between the concentration change rate of the electrolysis output node and the concentration change rate of the separation reflux node.

[0042] For any node concentration rate difference, calculate its mean over all normal cycles, and use it as the reference rate difference for node concentration rate differences.

[0043] Any node concentration rate difference less than or equal to 0 is marked as an abnormal rate difference;

[0044] The input error of the PID controller is calculated based on the difference between each abnormal rate and the corresponding reference rate.

[0045] As a preferred embodiment of the alkaline solution concentration and flow rate regulation system based on adaptive PID described in this application, the flow rate regulation module includes a PID unit and a regulation command unit;

[0046] The PID unit is equipped with a PID controller to execute the PID control strategy and calculate the flow adjustment amount of the circulating flow based on the corresponding input error.

[0047] The adjustment instruction unit generates a flow adjustment instruction based on the flow adjustment amount and sends it to the flow adjustment execution mechanism.

[0048] Secondly, this application provides a method for regulating the concentration and flow rate of alkaline solution based on adaptive PID, comprising the following steps:

[0049] Collect the alkali concentration at each cycle node;

[0050] Construct the concentration sequence for each cycle node based on the alkaline solution concentration;

[0051] The response characteristic index of alkali concentration is calculated based on the concentration sequence of each cycle node.

[0052] Based on the response characteristic index of alkali concentration, anomalies in concentration response are identified, and corresponding flow control strategies are matched based on the type of anomaly in concentration response.

[0053] The circulation flow rate of the alkali solution is adjusted in real time based on a flow control strategy.

[0054] Compared with the prior art, the beneficial effects achieved by this application are as follows:

[0055] This application can identify the instability trend of concentration distribution caused by multi-node, multi-path coupling structure when the overall value of alkali concentration does not deviate significantly from the set range. By regulating the circulation flow, it can intervene in the propagation relationship of alkali concentration between nodes in the circulation system, thereby suppressing the spread of local imbalance and maintaining overall operational stability. Attached Figure Description

[0056] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments 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. Wherein:

[0057] Figure 1 A schematic diagram of the structure of the alkaline solution concentration and flow rate regulation system based on adaptive PID provided in this application;

[0058] Figure 2 A flowchart of the alkaline solution concentration and flow rate regulation method based on adaptive PID provided in this application. Detailed Implementation

[0059] The technical solution of this application will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments and specific features in the embodiments are detailed descriptions of the technical solution of this application, rather than limitations thereof. In the absence of conflict, the embodiments and technical features in the embodiments can be combined with each other.

[0060] Example 1

[0061] This embodiment describes an alkaline solution concentration and flow rate regulation system based on adaptive PID control, referring to... Figure 1 The system includes a data acquisition module, a data processing module, a concentration analysis module, a control strategy module, and a flow regulation module; among which:

[0062] The data acquisition module is used to collect the alkali concentration at each cycle node;

[0063] The data acquisition module includes a concentration acquisition unit; the concentration acquisition unit is used to acquire the alkali concentration at each circulation node;

[0064] The concentration acquisition unit is equipped with a concentration detection device installed at each circulation node and has a preset continuous sampling period; at the beginning of each sampling period, the concentration acquisition unit simultaneously collects the alkali concentration at each circulation node.

[0065] Optionally, the concentration detection device can be a densitometer, conductivity sensor, etc., which directly measures the density or conductivity of the alkali solution at the corresponding location, and calculates the alkali solution concentration by means of the calibrated conversion relationship between density or conductivity and alkali solution concentration.

[0066] The circulation nodes include a liquid supply input node, an electrolysis output node, a separation reflux node, and a replenishment and mixing node.

[0067] The liquid supply input node is the main pipe position before the circulation pipeline enters the electrolytic cell group. The alkali concentration at this node is the input alkali concentration of the electrolytic reaction zone. The electrolysis output node is the alkali collection outlet position of the electrolytic cell group. The alkali concentration at this node is the output alkali concentration of the electrolytic reaction zone. The separation and reflux node indicates the position before the alkali flows back to the circulation pipeline after gas-liquid separation. The alkali concentration at this node reflects the impact of gas-liquid separation on the alkali state. The replenishment and mixing node is the position where the replenished alkali mixes with the circulating alkali in the circulation pipeline after injection. The alkali concentration at this node includes the impact of external disturbances on the original alkali concentration in the circulation. In the alkali circulation system, the replenished alkali is mixed with the circulating alkali at the replenishment mixing node to form a high-concentration alkali, which then reaches the supply input node through the circulation pipeline. After that, it enters the electrolytic cell group to participate in the electrolysis reaction. The alkali after the reaction is discharged from the electrolysis output node and enters the gas-liquid separation unit. After separation, the alkali forms a liquid phase and flows back to the separation return node, and is then circulated again to the replenishment mixing node to be mixed with the subsequent replenishment, thus forming a closed-loop propagation path for the alkali.

[0068] The data acquisition module also includes a flow acquisition unit; the flow acquisition unit is equipped with a flow meter for real-time acquisition of the circulating flow rate of the alkali solution.

[0069] Optionally, the flow acquisition unit is equipped with an electromagnetic flow meter and installed in the reflux manifold between the separation reflux node and the replenishment mixing node to obtain the circulating flow of the main circulation pipeline in real time.

[0070] The data processing module constructs a concentration sequence for each loop node based on the alkali concentration.

[0071] The data processing module includes a data cleaning unit and a data sorting unit;

[0072] The data cleaning unit is used to clean the alkaline concentration of each cycle node output by each concentration acquisition unit.

[0073] Optionally, the data cleaning includes, but is not limited to, outlier removal and missing value interpolation filling. For example, if a certain loop node has no valid alkali concentration sample value in any sampling period, the valid alkali concentration sample value of the corresponding loop node in the closest sampling period can be selected for filling, or the sampling values ​​of adjacent periods can be interpolated to form an aligned time series of alkali sampling data of each loop node under the same time reference, so as to ensure that subsequent calculations can be performed based on a consistent time reference.

[0074] The data processing unit organizes the alkaline concentration after data cleaning into a concentration sequence for each cycle node; the concentration sequence of any cycle node is a time series of the alkaline concentration of the corresponding node, including the alkaline concentration of the corresponding cycle node in multiple consecutive sampling periods.

[0075] The concentration analysis module calculates the response characteristic index of the alkali concentration based on the concentration sequence of each loop node;

[0076] The concentration analysis module includes a first analysis unit and a second analysis unit; the response characteristic indicators include the concentration change rate of each cycle node in each sampling period, and the node concentration difference and concentration gradient identifier between different cycle nodes in any sampling period.

[0077] The first analysis unit calculates the concentration change rate of each cycle node in each sampling period based on the concentration sequence of each cycle node. For any cycle node, the concentration change rate in any sampling period is the ratio of the concentration change to the length of the sampling period, and the concentration change in any sampling period is the difference between the alkali concentration of the corresponding sampling period and the alkali concentration of the adjacent previous sampling period.

[0078] The second analysis unit calculates the node concentration difference and concentration gradient identifier for each sampling period based on the concentration sequence of each cycle node; the node concentration difference includes the electrolysis concentration difference, the separation concentration difference, and the replenishment concentration difference;

[0079] For any sampling period, the second analysis unit calculates the corresponding nodal concentration difference, specifically including:

[0080] The difference between the alkali concentration at the electrolysis output node and the alkali concentration at the liquid supply input node is calculated as the electrolysis concentration difference for the corresponding sampling period.

[0081] The difference between the alkali concentration at the separation reflux node and the alkali concentration at the electrolysis output node is calculated as the separation concentration difference for the corresponding sampling period.

[0082] The difference between the alkali concentration at the replenishment mixing node and the alkali concentration at the separation reflux node is calculated as the replenishment concentration difference for the corresponding sampling period.

[0083] Electrolysis concentration difference indicates the degree of concentration change of the alkali solution before and after electrolysis due to the consumption of alkali in the electrolytic reaction. Separation concentration difference indicates the degree of concentration change of the alkali solution during gas-liquid separation due to gas evolution. Makeup concentration difference indicates the degree of concentration change of the reflux alkali solution after separation after the addition of makeup solution and the completion of preliminary mixing, reflecting the direct impact of makeup solution on the concentration of the original circulating alkali solution.

[0084] The concentration gradient identifier includes a first gradient identifier, a second gradient identifier, and a third gradient identifier;

[0085] For any sampling period, the second analysis unit calculates the concentration gradient identifier based on the corresponding node concentration difference, specifically including:

[0086] If the electrolysis concentration difference is greater than 0, the first gradient indicator is set to 1; otherwise, the first gradient indicator is set to -1.

[0087] If the concentration difference is greater than 0, the second gradient indicator is set to 1; otherwise, the second gradient indicator is set to -1.

[0088] If the concentration difference of the replenishing solution is less than 0, the value of the third gradient indicator is 1; otherwise, the value of the third gradient indicator is -1.

[0089] The control strategy module identifies concentration response anomalies based on the response characteristic indicators of alkali concentration, and matches the corresponding flow control strategy based on the type of concentration response anomaly.

[0090] The control strategy module includes an anomaly detection unit and a strategy matching unit;

[0091] The anomaly detection unit is configured with an anomaly detection strategy to identify concentration response anomalies; the concentration response anomalies include concentration gradient anomalies and propagation path anomalies.

[0092] The anomaly detection strategy includes: for any sampling period, if at least one of the first gradient identifier, the second gradient identifier, and the third gradient identifier is -1, then there is a concentration gradient anomaly.

[0093] Under normal operating conditions, water consumption during electrolysis leads to an increase in alkali concentration, resulting in an electrolysis concentration difference greater than 0. Gas-liquid separation causes partial water evaporation, resulting in a separation concentration difference greater than 0. Liquid replenishment dilutes the alkali, resulting in a replenishment concentration difference less than 0. When the system experiences flow anomalies such as local stagnation or reverse enrichment, the normal propagation relationship of alkali between circulation nodes is disrupted, leading to a reversal of the concentration gradient between adjacent circulation nodes. For example, if there is stagnation or a dead zone at the inlet of the electrolytic cell group, the local liquid forms a high-concentration region due to prolonged residence, resulting in a measured electrolysis concentration difference less than 0. Local deviations from the mainstream propagation path cause abnormal alkali concentrations measured at circulation nodes, and the direction of concentration change based on the location relationship of the circulation nodes no longer conforms to the normal propagation law.

[0094] The anomaly detection strategy further includes: for any sampling period, detecting whether the propagation path conditions are met; if at least one propagation path condition is not met, then there is a propagation path anomaly.

[0095] The propagation path conditions include: the concentration change rate at the liquid mixing node is greater than the concentration change rate at the liquid supply input node; the concentration change rate at the liquid supply input node is greater than the concentration change rate at the electrolysis output node; and the concentration change rate at the electrolysis output node is greater than the concentration change rate at the separation reflux node.

[0096] The replenishment of solution (pure water or low-concentration alkali solution) first affects the replenishment mixing node, and then sequentially influences the alkali concentration at the supply input node, electrolysis output node, and separation reflux node along the circulation path. In this propagation chain, the upstream node has the fastest alkali concentration response and the largest change amplitude. Due to the influence of solution mixing and diffusion, the amplitude of alkali concentration change gradually decreases, and the rate of concentration change shows a decreasing trend. When there are anomalies such as insufficient mixing, alkali in some areas may not participate in the transfer along the normal flow path, or alkali from different paths may arrive at each circulation node at different speeds, which will cause a misalignment in the concentration response sequence of each circulation node.

[0097] An abnormal concentration gradient disrupts the basic operating rules of the alkali circulation system, while an abnormal propagation path affects circulation efficiency and stability. In subsequent regulation, the abnormal concentration gradient should be the priority response.

[0098] The strategy matching unit is configured with a PID control strategy; the PID control strategy includes a basic PID strategy, a first control strategy, and a second control strategy.

[0099] Any PID control strategy is used to specify the input error and control output of the PID controller; wherein, in each PID control strategy, the control output of the PID controller is the flow regulation of the circulating flow.

[0100] The strategy matching unit matches the corresponding PID control strategy based on the type of concentration response anomaly and sends it to the flow regulation module; specifically including:

[0101] If an anomaly in the concentration gradient exists, the first control strategy is applied; if no anomaly in the concentration gradient exists, but an anomaly in the propagation path exists, the second control strategy is applied.

[0102] The basic PID strategy includes: setting a target alkali concentration; calculating the difference between the target alkali concentration and the alkali concentration at the supply input node, which is used as the input error of the PID controller.

[0103] Those skilled in the art can set the target alkali concentration based on actual needs; for example, a common industrial target alkali concentration is 25% to 30% to maintain high conductivity while suppressing corrosion. The selection of the supply input node is based on the fact that this node is located before the alkali enters the electrolytic cell assembly, and can directly reflect the state of the mainstream alkali participating in the reaction; at the same time, this location has taken into account the effects of replenishment mixing and reflux, and the alkali concentration is representative and stable.

[0104] Optionally, the basic PID strategy also includes setting the proportional, integral, and derivative coefficient values. Changes in alkali concentration are affected by circulation, mixing, and reaction processes, resulting in a slow response and significant lag. In contrast, the circulation flow rate, as the actuated variable, responds quickly, classifying it as a slow-variable process control system. To address this characteristic, the proportional, integral, and derivative coefficients can be set in a ratio of 10:1:0.1. The proportional component plays a dominant role, enabling the system to respond quickly to differences in alkali concentration and adjust the circulation flow rate promptly. The integral component is of moderate size to gradually eliminate steady-state deviations and ensure long-term concentration stability. The derivative component is small, used only to suppress fluctuations during the adjustment process and avoid over-adjustment due to measurement noise.

[0105] The first control strategy includes:

[0106] Sampling periods without abnormal concentration responses are marked as normal periods; for any node concentration difference, its mean value in all normal periods is calculated and used as the reference concentration difference for the node concentration difference.

[0107] Mark the node concentration difference corresponding to any concentration gradient with a value of -1 as an abnormal concentration difference;

[0108] The input error of the PID controller is calculated based on the difference between each abnormal concentration and the corresponding reference concentration.

[0109] Specifically, the abnormal concentration difference is subtracted from the corresponding reference concentration difference to obtain one component of the PID controller's input error. If there are multiple components, the sum of all components is calculated as the PID controller's input error. For example, if the first gradient indicator is -1, it indicates that the electrolysis concentration difference is less than or equal to 0, and the electrolysis concentration difference is an abnormal concentration difference. The electrolysis concentration difference is subtracted from the reference concentration difference to obtain one component of the input error. If the second or third gradient indicator is also -1, the input error component is calculated similarly based on the separation concentration difference or replenishment concentration difference and the corresponding reference concentration difference.

[0110] Optionally, the first control strategy also includes setting the value ratios of the proportional coefficient, integral coefficient, and derivative coefficient. The control objective of the first control strategy is to forcibly reconstruct the propagation direction of the alkali concentration. This requires a stronger ability to quickly correct deviations. An example of an optional value ratio is as follows: a ratio of 16:0.5:0.2 for the proportional coefficient, integral coefficient, and derivative coefficient. Compared to the basic PID strategy, increasing the proportional coefficient ratio enhances the immediate response to the reversal of the concentration difference at nodes; decreasing the integral coefficient ratio reduces the tailing caused by the accumulation of historical errors; and increasing the derivative coefficient ratio enhances the suppression of sudden changes in flow rate and oscillations.

[0111] Optionally, the first control strategy also includes constraints on the control output, such as limiting the flow rate adjustment of the circulating flow rate to be greater than 0, so as to ensure that the overall transport capacity of the fluid can be enhanced, the local enrichment state can be broken, and the rapid and uniform mixing of the replenishment liquid and the main circulating liquid can be promoted.

[0112] The second control strategy includes:

[0113] The concentration rate difference between the nodes is calculated, including a first rate difference, a second rate difference, and a third rate difference; wherein, the first rate difference is the difference between the concentration change rate of the liquid mixing node and the concentration change rate of the liquid input node; the second rate difference is the difference between the concentration change rate of the liquid input node and the concentration change rate of the electrolysis output node; and the third rate difference is the difference between the concentration change rate of the electrolysis output node and the concentration change rate of the separation reflux node.

[0114] For any node concentration rate difference, calculate its mean over all normal cycles, and use it as the reference rate difference for node concentration rate differences.

[0115] Any node concentration rate difference less than or equal to 0 is marked as an abnormal rate difference;

[0116] The input error of the PID controller is calculated based on the difference between each abnormal rate and the corresponding reference rate.

[0117] Specifically, the abnormal rate difference is subtracted from the corresponding reference rate difference to obtain one component of the PID controller's input error. If there are multiple components, the sum of all components is calculated as the PID controller's input error. For example, if the first rate difference is less than or equal to 0, the first rate difference is subtracted from the corresponding reference rate difference to obtain one component of the PID controller's input error. If the second or third rate difference is also less than or equal to 0, the other components of the PID controller's input error are calculated based on the corresponding reference rate difference.

[0118] Optionally, the second control strategy also includes setting the proportional, integral, and derivative coefficient values. The control objective of the second control strategy is to restore the continuous transmission of the dilution effect of the replenishment on the concentration along the circulation path. An example of an optional setting is as follows: the ratio of the proportional, integral, and derivative coefficients is 13:1.5:0.1; compared to the basic PID strategy, the increased ratio of the proportional and integral coefficients allows the PID controller to respond more quickly to node concentration rate misalignments and enhances its ability to correct persistent node concentration rate misalignments.

[0119] It should be noted that the numerical ratios of the proportional, integral, and derivative coefficients in each PID control strategy provided in this embodiment are only used to illustrate the control logic of the adaptive PID in this scheme and do not constitute a limitation on the parameters of the PID controller. Those skilled in the art can use the numerical ratios provided in this embodiment as a reference and, based on this, set the specific values ​​of the proportional, integral, and derivative coefficients using commonly used PID parameter tuning methods in the art, including but not limited to the step response method, the critical proportional method, or online tuning methods based on operating data, so that the system can achieve the requirements of stability and timely response in the corresponding PID control mode.

[0120] The flow regulation module adjusts the circulating flow rate of the alkali solution in real time based on the flow control strategy.

[0121] The flow regulation module includes a PID unit and a regulation command unit;

[0122] The PID unit is equipped with a PID controller to execute the PID control strategy and calculate the flow adjustment amount of the circulating flow based on the corresponding input error.

[0123] The adjustment instruction unit generates a flow adjustment instruction based on the flow adjustment amount and sends it to the flow adjustment execution mechanism.

[0124] Actuators such as circulating pumps and circulating control valves adjust the circulating flow rate by regulating the rotational speed or valve opening based on the flow rate regulation amount specified in the flow rate regulation command. Optionally, the control period of the PID controller is set to be the same as the sampling period, or set to an integer multiple of the sampling period, to ensure timing consistency between sampling and control.

[0125] Example 2

[0126] This embodiment is the second embodiment of this application; it is based on the same inventive concept as Embodiment 1, and refers to... Figure 2 This embodiment introduces a method for regulating the concentration and flow rate of alkali solution based on adaptive PID, including the following steps:

[0127] The concentration of alkali solution at each cycle node is collected; within a preset continuous sampling period, the concentration data of alkali solution is collected synchronously by a concentration detection device set at each cycle node; the concentration detection device can be a density transducer or a conductivity sensor, and the alkali solution concentration value is obtained by conversion through calibration relationship.

[0128] Based on the alkali concentration, a concentration sequence for each cycle node is constructed; the collected alkali concentration data is cleaned, including outlier removal and missing value interpolation, so that the data of each cycle node is aligned under a unified time reference; and the cleaned data is organized into a time series of the corresponding node within a continuous sampling period.

[0129] The response characteristic index of alkali concentration is calculated based on the concentration sequence of each cycle node; the concentration change rate of each cycle node in each sampling period is calculated based on the concentration sequence, as well as the node concentration difference and concentration gradient identifier between different cycle nodes; where the concentration change rate is the ratio of the concentration difference between adjacent sampling periods to the sampling period length.

[0130] Based on the response characteristic index of alkali concentration, concentration response anomalies are identified, and corresponding flow control strategies are matched based on the type of concentration response anomaly. The presence of concentration gradient anomalies is determined based on the concentration gradient identifier, and propagation path anomalies are determined based on the magnitude of the concentration change rate among each node. If a concentration gradient anomaly exists, the first control strategy is matched first; otherwise, the second control strategy is matched when a propagation path anomaly exists.

[0131] The circulating flow rate of the alkali solution is adjusted in real time based on a flow control strategy. A PID controller calculates the flow adjustment amount based on the input error corresponding to the strategy and generates a flow adjustment command that acts on the circulating pump or regulating valve to adjust the speed or valve opening, thereby achieving dynamic control of the circulating flow rate.

[0132] This application can identify the instability trend of concentration distribution caused by multi-node, multi-path coupling structure when the overall value of alkali concentration does not deviate significantly from the set range. By regulating the circulation flow, it can intervene in the propagation relationship of alkali concentration between nodes in the circulation system, thereby suppressing the spread of local imbalance and maintaining overall operational stability.

[0133] The specific functions of each of the above steps are described in the relevant content of the adaptive PID-based alkaline solution concentration and flow rate regulation system in Example 1, and will not be repeated here.

[0134] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0135] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of protection of this application, and these forms are all within the protection scope of this application.

Claims

1. A system for regulating the concentration and flow rate of alkali solution based on adaptive PID, characterized in that: It includes a data acquisition module, a data processing module, a concentration analysis module, a control strategy module, and a flow regulation module; among which: The data acquisition module is used to collect the alkali concentration at each cycle node; The data processing module constructs a concentration sequence for each loop node based on the alkali concentration. The concentration analysis module calculates the response characteristic index of the alkali concentration based on the concentration sequence of each loop node; The control strategy module identifies concentration response anomalies based on the response characteristic indicators of alkali concentration, and matches the corresponding flow control strategy based on the type of concentration response anomaly. The flow regulation module adjusts the circulating flow rate of the alkali solution in real time based on the flow control strategy; The concentration analysis module includes a second analysis unit; the response characteristic indicators include the node concentration difference and concentration gradient identifier between different cycle nodes within any sampling period; The second analysis unit calculates the node concentration difference and concentration gradient identifier for each sampling period based on the concentration sequence of each cycle node; the node concentration difference includes the electrolysis concentration difference, the separation concentration difference, and the replenishment concentration difference; For any sampling period, the second analysis unit calculates the corresponding nodal concentration difference, specifically including: The difference between the alkali concentration at the electrolysis output node and the alkali concentration at the liquid supply input node is calculated as the electrolysis concentration difference for the corresponding sampling period. The difference between the alkali concentration at the separation reflux node and the alkali concentration at the electrolysis output node is calculated as the separation concentration difference for the corresponding sampling period. The difference between the alkali concentration at the replenishment mixing node and the alkali concentration at the separation reflux node is calculated as the replenishment concentration difference for the corresponding sampling period.

2. The alkali concentration and flow rate regulation system based on adaptive PID as described in claim 1, characterized in that: The data acquisition module includes a concentration acquisition unit; the concentration acquisition unit is equipped with a concentration detection device installed at each cycle node, and a continuous sampling period is preset; at the beginning of each sampling period, the concentration acquisition unit simultaneously acquires the alkali concentration at each cycle node. The circulation node includes a liquid supply input node, an electrolysis output node, a separation reflux node, and a replenishment and mixing node; The data processing module includes a data processing unit; the data processing unit processes the alkali concentration into a concentration sequence for each cycle node; the concentration sequence of any cycle node is a time series of the alkali concentration of the corresponding node, including the alkali concentration of the corresponding cycle node in multiple consecutive sampling cycles.

3. The alkali concentration and flow rate regulation system based on adaptive PID as described in claim 2, characterized in that: The concentration analysis module includes a first analysis unit; the response characteristic index includes the concentration change rate of each loop node in each sampling period; The first analysis unit calculates the concentration change rate of each cycle node in each sampling period based on the concentration sequence of each cycle node. For any cycle node, the concentration change rate in any sampling period is the ratio of the concentration change to the length of the sampling period, and the concentration change in any sampling period is the difference between the alkali concentration of the corresponding sampling period and the alkali concentration of the adjacent previous sampling period.

4. The alkaline solution concentration and flow rate regulation system based on adaptive PID as described in claim 3, characterized in that: The concentration gradient identifier includes a first gradient identifier, a second gradient identifier, and a third gradient identifier; For any sampling period, the second analysis unit calculates the concentration gradient identifier based on the corresponding node concentration difference, specifically including: If the electrolysis concentration difference is greater than 0, the first gradient indicator is set to 1; otherwise, the first gradient indicator is set to -1. If the concentration difference is greater than 0, the second gradient indicator is set to 1; otherwise, the second gradient indicator is set to -1. If the concentration difference of the replenishing solution is less than 0, the value of the third gradient indicator is 1; otherwise, the value of the third gradient indicator is -1.

5. The alkali concentration and flow rate regulation system based on adaptive PID as described in claim 4, characterized in that: The control strategy module includes an anomaly detection unit; the anomaly detection unit is configured with an anomaly detection strategy for identifying concentration response anomalies. The concentration response anomalies include concentration gradient anomalies and propagation path anomalies. The anomaly detection strategy includes: for any sampling period, if at least one of the first gradient identifier, the second gradient identifier, and the third gradient identifier is -1, then there is a concentration gradient anomaly. The anomaly detection strategy further includes: for any sampling period, detecting whether the propagation path conditions are met; if at least one propagation path condition is not met, then there is a propagation path anomaly. The propagation path conditions include: the concentration change rate at the liquid mixing node is greater than the concentration change rate at the liquid supply input node; the concentration change rate at the liquid supply input node is greater than the concentration change rate at the electrolysis output node; and the concentration change rate at the electrolysis output node is greater than the concentration change rate at the separation reflux node.

6. The alkali concentration and flow rate regulation system based on adaptive PID as described in claim 5, characterized in that: The control strategy module further includes a strategy matching unit; the strategy matching unit is configured with a PID control strategy; the PID control strategy includes a basic PID strategy, a first control strategy, and a second control strategy. Any PID control strategy is used to specify the input error and control output of the PID controller; wherein, in each PID control strategy, the control output of the PID controller is the flow regulation of the circulating flow. The strategy matching unit matches the corresponding PID control strategy based on the type of concentration response anomaly and sends it to the flow regulation module; specifically including: If an anomaly in the concentration gradient exists, the first control strategy is applied; if no anomaly in the concentration gradient exists, but an anomaly in the propagation path exists, the second control strategy is applied.

7. The alkaline solution concentration and flow rate regulation system based on adaptive PID as described in claim 6, characterized in that: The basic PID strategy includes: setting a target alkali concentration; calculating the difference between the target alkali concentration and the alkali concentration at the supply input node, which is used as the input error of the PID controller; The first control strategy includes: marking sampling periods without abnormal concentration response as normal periods; and for any node concentration difference, calculating its average value in all normal periods as a reference concentration difference for the node concentration difference. Mark the node concentration difference corresponding to any concentration gradient with a value of -1 as an abnormal concentration difference; The input error of the PID controller is calculated based on the difference between each abnormal concentration and the corresponding reference concentration.

8. The alkali concentration and flow rate regulation system based on adaptive PID as described in claim 7, characterized in that: The second control strategy includes: calculating the concentration rate difference between nodes, including a first rate difference, a second rate difference, and a third rate difference; wherein, the first rate difference is the difference between the concentration change rate of the liquid replenishment mixing node and the concentration change rate of the liquid supply input node; the second rate difference is the difference between the concentration change rate of the liquid supply input node and the concentration change rate of the electrolysis output node; and the third rate difference is the difference between the concentration change rate of the electrolysis output node and the concentration change rate of the separation reflux node. For any node concentration rate difference, calculate its mean over all normal cycles, and use it as the reference rate difference for node concentration rate differences. Any node concentration rate difference less than or equal to 0 is marked as an abnormal rate difference; The input error of the PID controller is calculated based on the difference between each abnormal rate and the corresponding reference rate.

9. The alkali concentration and flow rate regulation system based on adaptive PID as described in claim 8, characterized in that: The flow regulation module includes a PID unit and a regulation command unit; The PID unit is equipped with a PID controller to execute the PID control strategy and calculate the flow adjustment amount of the circulating flow based on the corresponding input error. The adjustment instruction unit generates a flow adjustment instruction based on the flow adjustment amount and sends it to the flow adjustment execution mechanism.

10. A method for regulating the concentration and flow rate of alkali solution based on adaptive PID, implemented based on the adaptive PID-based alkali solution concentration and flow rate regulation system as described in any one of claims 1-9, characterized in that: Includes the following steps: Collect the alkali concentration at each cycle node; Construct the concentration sequence for each cycle node based on the alkaline solution concentration; The response characteristic index of alkali concentration is calculated based on the concentration sequence of each cycle node. Based on the response characteristic index of alkali concentration, anomalies in concentration response are identified, and corresponding flow control strategies are matched based on the type of anomaly in concentration response. The circulation flow rate of the alkali solution is adjusted in real time based on a flow control strategy.

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