Self-adaptive pumping and injecting balance control system for underground water circulating well based on multivariable fuzzy control

Abstract

The invention discloses a self-adaptive pumping and injecting balance control system for an underground water circulating well based on multivariable fuzzy control, which is characterized in that a packer divides the circulating well into an upper chamber and a lower chamber which are independent, and sieve holes communicated with environmental underground water are formed in the wall of the circulating well corresponding to the upper chamber and the lower chamber; the water pumping pipeline penetrates through the packer and is connected with a water outlet of the water pump, the water pump pumps water in the lower cavity to the upper cavity through the water pumping pipeline, an upper liquid level sensor is arranged in the upper cavity, a lower liquid level sensor is arranged in the lower cavity, and the control device is electrically connected with the water pump, the upper liquid level sensor, the lower liquid level sensor and the adjusting valve. The control device adjusts the opening degree of the adjusting valve and / or regulates and controls the operation frequency of the water pump through the frequency converter according to the liquid level information in the upper cavity and the lower cavity. According to the system, operation and maintenance are optimized, manual intervention is reduced, manual debugging is not needed under any hydrogeological condition, operation parameters are automatically adjusted, and pumping and injection balance is guaranteed.

Description

Technical Field

[0001] This invention belongs to the field of environmental protection technology, specifically, it relates to an adaptive injection-extraction balance control system for groundwater circulation wells based on multivariable fuzzy control. Background Technology

[0002] With the progress of global industrialization, a large amount of industrial wastewater and solid waste has been landfilled or leaked, causing toxic and harmful pollutants such as heavy metals, chlorinated hydrocarbons, petroleum hydrocarbons, and benzene compounds to enter underground aquifers.

[0003] The "groundwater extraction and treatment" technology extracts polluted groundwater from wells and treats it by building surface treatment facilities. This requires long-term and large-scale water extraction and operation of surface facilities, resulting in extremely high energy consumption and maintenance costs. The sludge or concentrate produced during treatment requires further disposal.

[0004] In-situ permeable reactive barrier (IPB) technology involves constructing a passive wall underground filled with reactive media, which is degraded or adsorbed as a pollutant plume flows through it. This technology lacks flexibility; once constructed, it is difficult to move or adjust and cannot adapt to changes in the pollutant plume's morphology. Biological or chemical blockage of the reactive media can lead to IPB failure, and the remediation effect depends entirely on the natural flow rate of groundwater, resulting in a long remediation cycle.

[0005] The subsequently developed "groundwater circulation well" technology actively creates a localized, three-dimensional, and controllable circulating flow field around the well by circulating groundwater below the surface. However, in complex and heterogeneous hydrogeological conditions, permeability varies greatly. During operation, the difference between pumping and injection rates leads to problems such as excessive pumping causing overflow, insufficient pumping flow preventing circulation, and repeated pump start-ups and shutdowns, requiring real-time intervention from maintenance personnel.

[0006] In the operation of groundwater circulation wells, the ideal state for the flow rate of pumping and reinjection is that the pumping and reinjection are balanced. However, the current circulation wells control the flow rate manually or control the pumping and injection balance by repeatedly starting and stopping. Summary of the Invention

[0007] To address the aforementioned technical problems in the existing technology, this invention provides an adaptive injection-extraction balance control system for groundwater circulation wells based on multivariate fuzzy control. By optimizing operation and maintenance and reducing manual intervention, it can automatically adjust operating parameters without manual debugging under any hydrogeological conditions to ensure injection-extraction balance.

[0008] The present invention adopts the following technical solution: An adaptive pumping-injection balance control system for groundwater circulating wells based on multivariate fuzzy control includes a control device, a packer installed in the circulating well, a pumping pipe, and a water pump. The packer divides the circulating well into an independent upper chamber and a lower chamber. The well wall corresponding to the upper and lower chambers has sieve holes communicating with groundwater. The pumping pipe passes through the packer and connects to the outlet of the water pump. A regulating valve is installed on the pumping pipe. The water pump pumps water from the lower chamber to the upper chamber through the pumping pipe. An upper liquid level sensor is installed in the upper chamber, and a lower liquid level sensor is installed in the lower chamber. The control device is electrically connected to the water pump, the upper liquid level sensor, the lower liquid level sensor, and the regulating valve. Based on the liquid level information in the upper and lower chambers, the control device uses a multivariate fuzzy method to control the flow rate and head of the water pump by controlling the operating frequency of the frequency converter and / or the opening of the regulating valve.

[0009] Furthermore, the water pumping pipe is also equipped with a regulating valve, which is electrically connected to the control device and is used to control the opening degree of the regulating valve.

[0010] The control device includes a data acquisition module, a fuzzy control module, a frequency control module, and a valve adjustment module. The data acquisition module receives real-time chamber liquid level information collected by the upper and lower liquid level sensors, as well as real-time valve opening information and inverter operating frequency information. The fuzzy control module is connected to the data acquisition module and has fuzzy inference rules. The fuzzy control module combines the current liquid level information, opening information, and frequency information to generate control commands according to the fuzzy inference rules, and transmits them to the frequency control module and valve adjustment module to control the pump operating frequency and valve opening, respectively.

[0011] Preferably, the fuzzy control module first regulates the operating frequency of the frequency converter, and then regulates the opening degree of the regulating valve.

[0012] Preferably, the fuzzy control module adapts to the nonlinear and variable characteristics of the circulating well, water pump, and upper and lower chambers, converting liquid level deviation, flow rate deviation, and head deviation into fuzzy commands. The fuzzy control module uses the centroid method to defuzzify, converting the fuzzy frequency adjustment amount Δf and valve opening adjustment amount Δθ into specific digital commands, and transmits them to the frequency adjustment module and valve opening adjustment module for execution, thereby adjusting the water pump operating frequency and regulating valve opening in real time.

[0013] Wherein, the liquid level deviation e_L = set liquid level L_set - actual liquid level L_act; The flow deviation e_Q = set constant flow rate Q_set - actual pumping flow rate Q_act; The head deviation e_H = minimum head H_min required for stable liquid level in the chamber - actual head H_act; The fuzzy control module compares the currently calculated flow deviation, head deviation, and liquid level deviation with the built-in fuzzy inference rules to generate the current fuzzy control scheme.

[0014] Furthermore, the fuzzy control module is also equipped with an adjustment dead zone. When the upper chamber liquid level deviation is less than ±1%, the flow rate deviation is less than ±2%, and the head deviation is less than ±1%, the fuzzy control module will not perform adjustment on the frequency converter and the regulating valve.

[0015] Preferably, the frequency adjustment module controls the inverter to adjust by 1-2 Hz at a time, and sets a delay of 5-8 seconds after frequency adjustment before determining whether to compensate for the adjustment of the regulating valve; the valve opening adjustment module controls the regulating valve to adjust by 2-3% at a time.

[0016] Furthermore, the fuzzy inference rules of the fuzzy control module also incorporate the liquid level change rate, which predicts the liquid level trend in the upper chamber and adjusts the frequency and valve opening in advance.

[0017] Preferably, the upper liquid level sensor and the lower liquid level sensor are respectively equipped with upper liquid level threshold and lower liquid level threshold in the corresponding upper chamber and lower chamber.

[0018] The present invention has the following advantages over the prior art: A. This invention installs corresponding upper and lower liquid level sensors in the upper and lower chambers of the pumping pipeline, respectively. After receiving the liquid level information from the upper and lower liquid level sensors, as well as the current opening degree of the regulating valve and the pump operating frequency, the control device adjusts the pump operating frequency and the opening degree of the regulating valve based on the liquid level in the upper and lower chambers, the pump flow rate and head information, using a multivariate fuzzy control method. This automatically adjusts the pumping flow rate and pressure, greatly reducing the commissioning process after the installation of the groundwater circulation well. At the same time, it can achieve unattended automatic operation during equipment operation, greatly reducing personnel costs and avoiding the problems of pump burnout due to low liquid level or frequent start-stop.

[0019] B. This invention also includes a regulating valve on the pumping pipeline. The control device prioritizes regulating the operating frequency of the frequency converter, minimizing disturbance to the liquid level in the chamber and preventing disruption to the already stable flow / liquid level. This enables regulation of the delivered water volume and pressure. This invention combines the regulating valve opening and frequency converter control, along with the fuzzy inference rules in the fuzzy control module, to quickly achieve a circulating balance of pumped and injected water between the upper and lower chambers, resulting in better circulation. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the specific embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the underground water circulation well system provided by the present invention.

[0022] Figure 2 This is a schematic diagram of the control device provided by the present invention.

[0023] The meanings in the diagram are as follows: 1-Control device; 2-Circulation well; 21-Upper chamber; 22-Lower chamber 3-Package; 4-Pumping pipe; 5-Water pump; 6-Upper liquid level sensor 7-Lower liquid level sensor; 8-Frequency converter; 9-Regulating valve, a-Upper liquid level line, b-Lower liquid level line. Detailed Implementation

[0024] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0026] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0027] like Figure 1 As shown, this invention provides an adaptive pumping-injection balance control system for groundwater circulation wells based on multivariate fuzzy control, including a control device 1, a packer 3 installed in the circulation well 2, a pumping pipe 4, and a water pump 5. The packer 3 divides the circulation well 2 into an independent upper chamber 21 and a lower chamber 22. The well wall of the circulation well 2, corresponding to the upper chamber 21 and the lower chamber 22, is provided with sieve holes that communicate with the ambient groundwater. The sieve holes are set in a reasonable position in the upper chamber 21. The pumping pipe 4 passes through the packer 3 and connects to the outlet of the water pump 5. The water pump 5 pumps water from the lower chamber 22 to the upper chamber 21 through the pumping pipe 4. The upper chamber 21 is equipped with an upper liquid level sensor 6, and the lower chamber 22 is equipped with a lower liquid level sensor 7. The control device 1 is electrically connected to the water pump 5, the upper liquid level sensor 6, and the lower liquid level sensor 7. The upper and lower liquid level sensors 6 and 7 monitor the liquid level in their respective chambers in real time and transmit the collected liquid level information to the control device 1. Preferably, the control device 1 uses PLC program control. Based on the liquid level information in the upper and lower chambers 21, the control device 1 adjusts the operating frequency of the water pump 5 via a frequency converter 8. By controlling the pump frequency based on the liquid level monitoring information in the upper and lower chambers, the control device achieves a pumping balance between the upper and lower chambers, eliminating the need for repeated on-site operation by personnel, greatly reducing manual intervention and lowering labor costs.

[0028] As a further preferred embodiment of the present invention, a regulating valve 9 is also provided on the pumping pipe 4. The regulating valve 9 can be a pneumatic or electric regulating valve. Its control signal line is connected to the control device. The control device 1 controls the opening of the regulating valve 9 according to the collected liquid level information to regulate the water output of the pump, thereby achieving rapid adjustment of the pumping balance between the upper chamber and the lower chamber.

[0029] The upper liquid level sensor 6 and the lower liquid level sensor 7 are respectively set with upper liquid level thresholds and lower liquid level thresholds in their corresponding upper chamber 21 and lower chamber 22. The upper liquid level thresholds and lower liquid level thresholds can be a range, such as... Figure 1 The upper and lower liquid level lines are respectively set in the upper and lower chambers.

[0030] The specific injection balance control logic is as follows: When the liquid level detected by the current liquid level sensor 7 is not lower than the lower liquid level line, and the liquid level detected by the upper liquid level sensor 6 is not higher than the upper liquid level line, the water pump can be started to pump water. When the current liquid level sensor 7 detects that the liquid level has reached the lower liquid level line, or the upper liquid level sensor 6 detects that the liquid level has reached the upper liquid level line, the water pump frequency is gradually reduced to decrease the flow rate. When the liquid levels in the upper and lower chambers remain unchanged, the frequency adjustment is stopped. When the water pump frequency is reduced to the set frequency (generally 25-30Hz), the frequency is no longer reduced, but the opening of the regulating valve is adjusted to reduce the flow rate until the liquid levels in the upper and lower chambers remain unchanged, at which point the adjustment is stopped.

[0031] After the operation is stable, the liquid level change in the upper and lower chambers is set to a range threshold. When the liquid level exceeds the range, the pumping volume and pumping pressure are adjusted by adjusting the pump frequency or regulating the valve opening to control the liquid level change within the set threshold.

[0032] If the liquid level in the lower chamber rises above a threshold (which can be set manually), the pump frequency is increased or the regulating valve opening is widened. If the liquid level in the lower chamber drops above a threshold, the inverter frequency is decreased or the regulating valve opening is narrowed. If the liquid level in the upper chamber rises above a threshold (which can be set manually), the inverter frequency is decreased or the regulating valve opening is narrowed. If the liquid level in the upper chamber drops above a threshold (which can be set manually), the pump frequency is increased or the regulating valve opening is widened.

[0033] like Figure 2 As shown, the control device includes a data acquisition module, a fuzzy control module, a frequency control module, and a valve adjustment module. The data acquisition module receives real-time information on the chamber level from the upper and lower level sensors, as well as real-time information on the opening degree of the regulating valve and the operating frequency of the frequency converter. The fuzzy control module is connected to the data acquisition module and has fuzzy inference rules. The fuzzy control module combines the current level information, opening degree information, and frequency information to generate control commands according to the fuzzy inference rules and transmits them to the frequency control module and the valve adjustment module to control the operating frequency of the water pump and the opening degree of the regulating valve, respectively.

[0034] The specific module control method of the fuzzy control module is as follows: by adapting to the nonlinear and variable characteristics of the circulating well, water pump, and upper and lower chambers, the liquid level deviation, flow rate deviation, and head deviation are converted into fuzzy commands; the fuzzy control module uses the centroid method to defuzzify, converting the fuzzy frequency adjustment amount Δf and valve opening adjustment amount Δθ into specific digital commands, and transmitting them to the frequency adjustment module and valve opening adjustment module for execution, thereby adjusting the water pump operating frequency and the valve opening in real time. Wherein: Liquid level deviation e_L = Set liquid level L_set - Actual liquid level L_act; Flow deviation e_Q = Set constant flow rate Q_set - Actual pumping flow rate Q_act; Head deviation e_H = Minimum head required for stable liquid level in the chamber H_min - Actual head H_act; The fuzzy control module compares the currently calculated flow deviation, head deviation, and liquid level deviation with the built-in fuzzy inference rules to generate the current fuzzy control scheme.

[0035] In the groundwater circulation well system, this invention adopts fuzzy control guided by "small fluctuations in the upper chamber liquid level (core objective) → constant pumping flow rate + sufficient head (execution objective)". The core logic is to control the flow rate and stabilize the liquid level with frequency regulation as the core, while valve regulation is only used for head compensation / endurance under extreme conditions. The priority is: frequency regulation > valve regulation. Fuzzy control adapts to the nonlinear and time-varying characteristics of the well-pump-chamber (such as fluctuations in groundwater recharge), and converts the liquid level / flow rate / head deviations into fuzzy commands to achieve regulation with no overshoot and low fluctuations.

[0036] The fuzzy control core logic relationship used in this invention differs from that of general pipeline systems. In the circulating well scenario, it is necessary to additionally couple the core feedback of "upper chamber liquid level" (liquid level fluctuations directly reflect the flow supply and demand balance). The overall logic consists of three steps: "fuzzification → rule reasoning → defuzzification execution". Step 1: Blur Processing ① Input quantity: Three core input variables were selected (to meet the requirements of chamber liquid level control), and each was divided into seven fuzzy subsets: "Negative Large (NB), Negative Medium (NM), Negative Small (NS), Zero (ZO), Positive Small (PS), Positive Medium (PM), and Positive Large (PB)". Chamber level deviation e_L: Set level L_set - Actual level L_act (e_L > 0 = Low level, need to increase flow rate to replenish water; e_L < 0 = High level, need to decrease flow rate to control water). Flow deviation e_Q: Set constant flow rate Q_set - actual pumping flow rate Q_act (e_Q > 0 = insufficient flow, e_Q < 0 = excessive flow); Head deviation e_H: Minimum head H_min required for stable chamber liquid level - actual head H_act (e_H>0 = insufficient head, unable to overcome chamber / well casing resistance; e_H<0 = excess head).

[0037] ② Output quantity (fuzzy output before defuzzification) Two output variables, also divided into seven fuzzy subsets, with adjustment ranges adapted to the slow-response characteristics of the water pump + circulating well system: Frequency adjustment amount Δf: The amount of frequency increase or decrease of the inverter (Δf > 0 for frequency increase, Δf < 0 for frequency decrease, single adjustment range 1-2Hz, to avoid sudden changes in flow rate); Valve opening adjustment amount Δθ: The amount of increase or decrease in the opening of the outlet valve (Δθ>0 means larger opening, Δθ<0 means smaller closing, single adjustment range 2%-3%, to avoid sudden changes in resistance).

[0038] Step 2: Fuzzy Inference Rules (Adapted to Circular Well Scenarios) The rule design follows the principles of "liquid level priority, flow rate core, and head as a safety net," with typical core rules shown in the table below (covering mainstream operating conditions):

[0039] Step 3: Defuzzification and Execution This invention employs the centroid method for defuzzification (adapting to slow response systems and avoiding overshoot), converting the fuzzy values ​​Δf and Δθ into specific digital instructions (e.g., Δf = 1.5Hz, Δθ = 2%). Add adjustment dead zone: Do not adjust when liquid level deviation < ±1%, flow rate deviation < ±2%, and head deviation < ±1%; Add a delay to the execution: After frequency adjustment, wait 5-8 seconds (the water pump-chamber liquid level response is delayed) before determining whether valve compensation is needed to avoid erroneous adjustment.

[0040] The core priorities of this invention are as follows: frequency regulation is the first priority (core method), and valve regulation is the second priority (only for compensation / backup). The specific hierarchy and basis are as follows: 1. First priority: Frequency regulation (the core of flow control and liquid level stabilization) Applicable scenarios: Over 95% of normal operating conditions (mainly liquid level / flow rate deviation, head deviation ≤ NS / PS); Priority criteria: ① Frequency directly controls the submersible pump speed. According to the similarity law, the speed is proportional to the flow rate. Adjusting the frequency can accurately and linearly change the pumping flow rate, directly matching the replenishment needs of the chamber liquid level (increasing the frequency = increasing the flow rate to replenish water, decreasing the frequency = decreasing the flow rate to control water), and minimizes the disturbance to the liquid level. ② In circulating wells, the chamber volume is small and the liquid level is sensitive to changes in flow rate. The "soft regulation" characteristic of frequency regulation (no resistance change) can avoid large fluctuations in liquid level, while valve regulation is prone to cause sudden changes in pipeline resistance, resulting in sudden changes in flow rate and liquid level oscillation. ③ Frequency regulation can simultaneously take into account the head (increasing the frequency increases the head, decreasing the frequency decreases the head), which can meet the basic requirement of "sufficient head" without the need for additional valve adjustment.

[0041] 2. Second priority: Valve regulation (head compensation only / last resort under extreme conditions) Applicable scenarios: Triggered only in two situations, and must be executed after the frequency is adjusted to the correct level: ① The frequency has reached its limit (maximum 50Hz / minimum 25Hz), but the flow rate / liquid level still does not meet the standard, and the head deviation is significant (e.g., if the flow rate is still insufficient and the head is too low at 50Hz, the valve can be slightly opened to reduce resistance; if the flow rate is still excessive and the head is too high at 25Hz, the valve can be slightly closed to limit the flow). ② The liquid level / flow rate has reached the standard, but the head deviation reaches PM / PB (e.g., the head is too high, causing the water to enter the chamber too quickly, or the head is too low, making it impossible to deliver water to the chamber). The priority criteria adopted in this invention are based on the following three points: ① Valve regulation is a "passive throttling / flow amplification" method, which changes the pipeline resistance and can easily disrupt the already stable flow rate / liquid level. Therefore, it is only used for compensation. ② The resistance characteristics of the well casing / packer in the circulating well are fixed. Large valve adjustments may cause cavitation in the pump (valve closure) or a sudden rise in the fluid level in the chamber (valve opening). Only small and delayed adjustments are possible. ③ Avoid fully closing / fully opening valves: Limit the opening to 10%-90% to prevent water shortage in the chamber (fully closed) or loss of liquid level control (fully open).

[0042] The priority execution principle adopted in this invention is as follows: Adjustment sequence: First adjust the frequency → wait for the system to stabilize (5-8 seconds) → if the liquid level / flow rate / head still does not meet the requirements, then adjust the valve; Adjustment range: Frequency can be adjusted by 1-2Hz in a single adjustment, and valve can be adjusted by 2%-3% in a single adjustment (valve range < frequency). Boundary protection: the frequency should not exceed 25-50Hz, the valve should not exceed 10%-90%, and the liquid level should be rechecked after the valve is adjusted. If the fluctuation exceeds the threshold, the frequency should be adjusted back.

[0043] If the groundwater recharge fluctuates greatly (such as the difference between rainy and dry seasons), the "liquid level change rate" can be added as an auxiliary input to the fuzzy inference rules to predict the liquid level trend. For example, if the liquid level drops rapidly, the frequency can be increased slightly in advance to improve the response speed. Compared with general PID, fuzzy control is more suitable for the "hysteresis + nonlinearity" of the circulating well system (such as the liquid level in the well dropping during pumping, causing the head to change slowly), and can avoid PID overshoot (such as when the liquid level is low, the frequency adjustment is too strong, causing the liquid level to rise).

[0044] Any aspects not described in this invention are applicable to existing technologies.

[0045] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. An adaptive pumping-injection balance control system for groundwater circulation wells based on multivariable fuzzy control, comprising a control device (1), a packer (3) disposed in a circulation well (2), a pumping pipe (4), and a water pump (5), wherein the packer (3) divides the circulation well (2) into an independent upper chamber (21) and a lower chamber (22), and the well wall of the circulation well (2) corresponding to the upper chamber (21) and the lower chamber (22) is provided with a screen hole communicating with groundwater, the pumping pipe (4) passes through the packer (3) and is connected to the outlet of the water pump (5), and the pumping pipe (4) is provided with a regulating valve (9); the water pump (5) pumps water from the lower chamber (22) to the upper chamber (21) through the pumping pipe (4), characterized in that, The upper chamber (21) is equipped with an upper liquid level sensor (6), and the lower chamber (22) is equipped with a lower liquid level sensor (7). The control device (1) is electrically connected to the water pump (5), the upper liquid level sensor (6), the lower liquid level sensor (7), and the regulating valve (9) respectively. The control device (1) adjusts the flow rate and head of the water pump (5) by controlling the operating frequency of the frequency converter (8) and / or the opening degree of the regulating valve (9) according to the liquid level information in the upper chamber (21) and the lower chamber (22) in a multivariate fuzzy manner.

2. The adaptive injection-extraction balance control system for groundwater circulation wells according to claim 1, characterized in that, The control device includes a data acquisition module, a fuzzy control module, a frequency control module, and a valve adjustment module. The data acquisition module receives in real time the chamber liquid level information collected by the upper and lower liquid level sensors, as well as the opening information of the regulating valve and the operating frequency information of the frequency converter. The fuzzy control module is connected to the data acquisition module and is equipped with fuzzy inference rules. The fuzzy control module combines the current liquid level information, opening information, and frequency information to generate control commands according to the fuzzy inference rules and transmits them to the frequency control module and the valve adjustment module to control the operating frequency of the water pump and the opening of the regulating valve, respectively.

3. The adaptive injection-extraction balance control system for groundwater circulation wells according to claim 2, characterized in that, The fuzzy control module first regulates the operating frequency of the frequency converter, and then regulates the opening degree of the regulating valve.

4. The adaptive injection-extraction balance control system for groundwater circulation wells according to claim 3, characterized in that, The fuzzy control module adapts to the nonlinear and variable characteristics of the circulating well, water pump, and upper and lower chambers, converting liquid level deviation, flow rate deviation, and head deviation into fuzzy commands. The fuzzy control module uses the centroid method to defuzzify, converting the fuzzy frequency adjustment amount Δf and valve opening adjustment amount Δθ into specific digital commands, which are then transmitted to the frequency adjustment module and valve opening adjustment module for execution, thereby adjusting the water pump operating frequency and regulating valve opening in real time.

5. The adaptive injection-extraction balance control system for groundwater circulation wells according to claim 4, characterized in that, The liquid level deviation e_L = set liquid level L_set - actual liquid level L_act; The flow deviation e_Q = set constant flow rate Q_set - actual pumping flow rate Q_act; The head deviation e_H = minimum head H_min required for stable liquid level in the chamber - actual head H_act; The fuzzy control module compares the currently calculated flow deviation, head deviation, and liquid level deviation with the built-in fuzzy inference rules to generate the current fuzzy control scheme.

6. The adaptive injection-extraction balance control system for groundwater circulation wells according to claim 5, characterized in that, The fuzzy control module is also equipped with an adjustment dead zone. When the upper chamber liquid level deviation is less than ±1%, the flow rate deviation is less than ±2%, and the head deviation is less than ±1%, the fuzzy control module will not perform adjustment on the frequency converter and the regulating valve.

7. The adaptive injection-extraction balance control system for groundwater circulation wells according to claim 5, characterized in that, The frequency adjustment module controls the inverter to adjust by 1-2 Hz in a single operation, and sets a delay of 5-8 seconds after frequency adjustment before determining whether to compensate for the adjustment of the regulating valve; the valve opening adjustment module controls the regulating valve to adjust by 2-3% in a single operation.

8. The adaptive injection-extraction balance control system for groundwater circulation wells according to claim 7, characterized in that, The fuzzy inference rules of the fuzzy control module also include the liquid level change rate, which predicts the liquid level trend in the upper chamber and adjusts the frequency and valve opening in advance.

9. The adaptive pumping-injection balance control system for groundwater circulation wells according to any one of claims 1-8, characterized in that, The upper liquid level sensor (6) and the lower liquid level sensor (7) are respectively set with upper liquid level threshold and lower liquid level threshold in the corresponding upper chamber (21) and lower chamber (22).

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