Electrolyte flow precision regulation system and method based on variable frequency circulating pump

Abstract

This invention relates to the field of hydrogen production technology, and more particularly to a system and method for precise control of electrolyte flow rate based on a variable frequency circulating pump. It includes: a variable frequency circulating pump set with a dual-redundancy structure, wherein the main pump and the standby pump are coaxially linked, forming a bidirectional pressure balance loop with the electrolyte circulation pipeline; a multi-parameter fusion detection module, integrating a high-frequency sampling flow meter, an anion concentration sensor with temperature compensation function, and a three-channel pressure transmitter, wherein the signals from each sensor are processed in a time-synchronized manner to generate a joint detection data packet; and a dynamic compensation controller, which has a built-in anion migration characteristic database and an electrolyte rheological model, and generates control commands with anti-compensation function based on real-time changes in anion concentration. This application can sense changes in multiple physical field parameters of the electrolyte in real time, dynamically correct control commands, and has strong anti-interference capabilities.

Description

Technical Field

[0001] This invention relates to the field of hydrogen production technology, and in particular to a system and method for precise control of electrolyte flow based on a variable frequency circulating pump. Background Technology

[0002] In-depth research into existing technologies in electrolyte control reveals serious technical bottlenecks in current electrolyte flow control systems when dealing with complex conditions such as high concentrations, multiphase states, and strong corrosion. Traditional solutions are mostly based on linear adjustment of a single physical field parameter, which cannot meet the core requirements of modern industry for precision electrolysis processes. Specifically, existing technologies suffer from the following key defects: Parameter detection lag: Conventional systems use a split sensor architecture, resulting in millisecond-level time differences in the acquisition of key parameters such as flow rate, concentration, and pressure. When the electrolyte anion concentration changes abruptly, the response delay of the control system leads to a flow overshoot of 8-12%, severely affecting hydrogen production efficiency. Simplified and distorted control model: Mainstream control algorithms treat anion mobility as a fixed parameter, ignoring the nonlinear impact of concentration changes on ion transport efficiency. Experiments show that when the electrolyte concentration exceeds 3 mol / L, the flow control error of the traditional model increases exponentially. The system has weak anti-interference ability: the existing technology lacks effective treatment of the coupling effect between the electrolyte rheological properties and the mechanical actuator, resulting in: water hammer effect caused by pressure fluctuation causing flow oscillation; and concentration detection drift caused by suspended particle interference.

[0003] The pressure shock during pump switching causes a chain of control imbalances. These problems severely restrict the application of electrolyte technology in hydrogen production. There is an urgent need for a flow control technology that can sense changes in multi-physical field parameters of the electrolyte in real time, dynamically correct control commands, and has strong anti-interference capabilities. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and proposes a precise electrolyte flow control system based on a variable frequency circulating pump, comprising:

[0005] The variable frequency circulating pump set with dual redundancy structure has a coaxial linkage design between the main pump and the standby pump, forming a bidirectional pressure balance loop with the electrolyte circulation pipeline.

[0006] The multi-parameter fusion detection module integrates a high-frequency sampling flow meter, an anion concentration sensor with temperature compensation function, and a three-channel pressure transmitter. The signals from each sensor are processed by time synchronization to generate a joint detection data packet.

[0007] The dynamic compensation controller has a built-in database of anion migration characteristics and an electrolyte rheological model. It generates control commands with anti-compensation function based on the real-time changes in anion concentration.

[0008] Multi-stage actuator, including a frequency converter drive unit with flow pre-calibration function and an electric regulating valve with non-linear opening compensation;

[0009] The intelligent closed-loop feedback unit adopts a staged triggering mechanism. When a combined anomaly of flow deviation and anion concentration change rate is detected, multi-parameter fusion control is initiated.

[0010] The above technical solution employs a five-module collaborative control system. A variable frequency pump unit serves as the execution terminal, a multi-parameter detection module synchronously acquires flow rate, anion concentration, and pressure, a dynamic control module generates commands based on an electrochemical compensation algorithm, an execution module implements dual-channel control of speed and valves, and a closed-loop feedback module establishes a deviation triggering mechanism. This solution addresses the problems of delayed feedback on anion concentration changes caused by single-sensor detection, the control algorithm's failure to consider the coupling effect of electrochemical parameters, and the reliance on manual intervention for fault recovery in existing technologies.

[0011] Preferably, the control algorithm of the dynamic compensation controller satisfies the following conditional expression:

[0012] ;

[0013] in: This refers to the output speed of the variable frequency circulating pump. For target traffic; Current traffic; This refers to the concentration of anions. This is the effective mobility coefficient; For pipeline pressure difference; , This represents the pump body characteristic constant.

[0014] The above technical solution innovatively introduces an anion mobility correction factor to construct a system that includes the target flow difference. Anion concentration Effective migration rate and pressure difference The multivariable control equations, through pump body characteristic constants , Achieve normalization processing.

[0015] Further preferably, the effective mobility coefficient The calculation formula is:

[0016] ;

[0017] in: The baseline mobility; This is the concentration decay coefficient.

[0018] The above technical solution is adopted: This solution overcomes the limitations of traditional linear models by establishing an exponential decay function, and utilizes the concentration decay coefficient. Achieve nonlinear correction of mobility.

[0019] More preferably, the phased triggering mechanism of the intelligent closed-loop feedback unit specifically includes:

[0020] Initial triggering phase: When the absolute value of the flow deviation exceeds 5% of the target value for 2 consecutive seconds, the basic compensation mode is activated;

[0021] Secondary triggering phase: When the rate of change in anion concentration exceeds 0.2 mol / (L·s) and is accompanied by a pressure fluctuation value greater than 10 kPa, the emergency pressure stabilization mode is activated;

[0022] Final triggering stage: When a nonlinear coupling deviation between anion concentration and flow rate is detected, the expert decision-making system is activated to perform multi-objective optimization.

[0023] Using the above technical solution: This solution can establish a graded response strategy by setting dual threshold triggering conditions (flow deviation > 5% or concentration change rate > 0.2 mol / (L·s)).

[0024] More preferably, the anion concentration sensor adopts the following design:

[0025] The built-in reference electrode automatic calibration module performs zero-point drift compensation every 30 seconds.

[0026] A porous ceramic diffusion barrier is set up to effectively isolate the interference of suspended particles in the electrolyte;

[0027] It is equipped with a dual-range detection channel, with different sensitivity coefficients used in the concentration ranges of 0-5 mol / L and 5-10 mol / L.

[0028] The above technical solution adopts an ion-selective electrode array, integrating three innovative designs: automatic calibration, porous ceramic barrier, and dual-range detection.

[0029] More preferably, the dual-redundancy structure of the variable frequency circulating pump set includes:

[0030] When the main pump is running, the standby pump remains in a pre-pressurized state, maintaining a standby condition of 50% of the rated speed;

[0031] A dynamic torque balancing coupling is installed between the two pumps to control pressure fluctuations within ±3% during switching.

[0032] The pump body's flow-through components are coated with anionic inert coating with a thickness of 200-300μm.

[0033] The above technical solution is adopted: This solution uses a parallel design of main and standby pumps, a dynamic torque balancing coupling, and an anionic inert coating on the flow parts. This can solve the problems of excessive pressure shock during pump switching and shortened pump life caused by anionic corrosion that exist in conventional redundant designs.

[0034] A method, applied to an electrolyte flow precision control system based on a variable frequency circulating pump as described in any one of the above, characterized in that it comprises:

[0035] S1. System self-learning initialization: Load the corresponding anion migration characteristic curve according to the electrolyte type code, and establish a three-dimensional control model of flow rate-concentration-pressure;

[0036] S2. Multi-source data fusion acquisition: Simultaneously acquire flow meter pulse signals, anion concentration gradient values, and pipeline pressure distribution maps with a period of 10ms;

[0037] S3. Dynamic Compensation Decision Generation: Based on the trend of anion concentration change, predict the rheological properties in the next 3 seconds, and calculate the mobility compensation coefficient and pressure attenuation factor;

[0038] S4. Multi-actuator coordinated control: The compensated target parameters are decomposed into variable frequency pump speed control quantity and valve opening correction quantity, and feedforward-feedback composite regulation is implemented;

[0039] S5. Intelligent closed-loop optimization: When a flow field distortion caused by a sudden change in anion concentration is detected, it automatically switches to a multi-level safety control strategy.

[0040] The above technical solution is adopted: This solution establishes a five-step control paradigm, focusing on achieving dynamic mobility compensation in the S3 stage and setting safety redundancy in the S5 stage; it can solve the problems of traditional technical solutions, such as response lag caused by a control cycle of up to 500ms and the lack of a mechanism to deal with sudden changes in anion concentration.

[0041] More preferably, the mobility compensation coefficient in step S3 is calculated using:

[0042] ;

[0043] in, This is a mobility correction factor; This represents the change in anion concentration per unit time. This represents the initial anion concentration; These are constants related to the electrolyte type.

[0044] The above technical solution addresses the problems of insufficient compensation and system oscillation caused by drastic concentration changes in traditional linear correction models by constructing quadratic function-type correction coefficients and strengthening compensation during concentration abrupt changes.

[0045] More preferably, the feedforward-feedback composite adjustment in step S4 includes:

[0046] Feedforward control: A reference rotation speed command is generated based on the rate of change of anion concentration, and a sliding mode variable structure control algorithm is used to suppress overshoot;

[0047] Feedback compensation stage: Calculate the regional flow resistance difference based on the real-time pressure distribution map and generate a nonlinear compensation curve for the valve opening;

[0048] Dynamic coupling correction: Perform a control parameter coupling analysis every 500ms and adjust the synergistic weight of speed and valve opening.

[0049] The above technical solution employs a three-channel parallel processing approach (base speed calculation, demand forecasting, and valve compensation) to implement feedforward-feedback coupled control. This addresses the limitations of traditional serial control modes.

[0050] The problem is that the rotation speed and valve action are not synchronized, which causes hydraulic impact and the insufficient prediction accuracy leads to a large overshoot.

[0051] More preferably, the multi-level security control strategy specifically includes:

[0052] Level 1 response: When the rate of change in anion concentration exceeds 0.5 mol / (L·s), start the backup circulation pipeline and increase the pump speed to the safety threshold;

[0053] Level 2 response: When a pressure pulsation frequency exceeds 50Hz, the flow field stabilizer is automatically injected and the pipeline damping device is activated;

[0054] Level 3 Response: When an inverse coupling trend between anion concentration and flow rate is observed, switch to the emergency control mode stored in the expert database.

[0055] The above technical solution establishes a three-level response mechanism, including high-response mode activation, speed increase, and backup pipeline switching. This can solve the problems of existing emergency solutions' single response mode being unable to cope with complex faults and the high startup time of the backup system. Attached Figure Description

[0056] Figure 1 This is a block diagram of the electrolyte flow rate precision control system based on a variable frequency circulating pump according to this application;

[0057] Figure 2This is a flowchart of the method for precise control of electrolyte flow based on a variable frequency circulating pump, as described in this application. Detailed Implementation

[0058] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0059] Please see Figure 1 Traditional electrolyte control systems suffer from the following technical drawbacks: single-sensor detection leads to a delay in feedback of anion concentration changes (approximately 3-5 seconds); the control algorithm does not consider the coupling effect of electrochemical parameters; and fault recovery relies on manual intervention. Based on this, this application proposes a precise electrolyte flow rate control system based on a variable frequency circulating pump, comprising:

[0060] The variable frequency circulating pump set with dual redundancy structure has a coaxial linkage design between the main pump and the standby pump, forming a bidirectional pressure balance loop with the electrolyte circulation pipeline.

[0061] The multi-parameter fusion detection module integrates a high-frequency sampling flow meter, an anion concentration sensor with temperature compensation function, and a three-channel pressure transmitter. The signals from each sensor are processed by time synchronization to generate a joint detection data packet.

[0062] The dynamic compensation controller has a built-in database of anion migration characteristics and an electrolyte rheological model. It generates control commands with anti-compensation function based on the real-time changes in anion concentration.

[0063] Multi-stage actuator, including a frequency converter drive unit with flow pre-calibration function and an electric regulating valve with non-linear opening compensation;

[0064] The intelligent closed-loop feedback unit adopts a staged triggering mechanism. When a combined anomaly of flow deviation and anion concentration change rate is detected, multi-parameter fusion control is initiated.

[0065] It is worth mentioning that this solution constructs a five-module collaborative control system, using a variable frequency pump unit as the execution terminal. A multi-parameter detection module synchronously collects flow rate, anion concentration, and pressure; a dynamic control module generates commands based on an electrochemical compensation algorithm; the execution module implements dual-channel regulation of speed and valves; and a closed-loop feedback module establishes a deviation triggering mechanism. This solution effectively addresses the problems in existing technologies, such as delayed feedback of anion concentration changes due to single-sensor detection; the control algorithm's failure to consider the coupling effect of electrochemical parameters; and the reliance on manual intervention for fault recovery.

[0066] The technical effects of the above embodiments include: shortening the detection response time; improving the accuracy of flow control; and ensuring the success rate of system fault self-recovery.

[0067] Existing technologies, for example, use fixed mobility parameters, which leads to:

[0068] Under high-concentration electrolyte conditions, the flow rate deviation reaches 8-12%; and pressure fluctuations trigger a chain reaction of control misalignment. Based on this, the control algorithm of the dynamic compensation controller satisfies the following conditional expression:

[0069] ;

[0070] in: This refers to the output speed of the variable frequency circulating pump. For target traffic; Current traffic; This refers to the concentration of anions. This is the effective mobility coefficient; For pipeline pressure difference; , This represents the pump body characteristic constant.

[0071] The above formula is the core algorithm of the dynamic control module, which for the first time couples the anion migration characteristics with hydrodynamic parameters for calculation. The formula is based on the synergistic effect of electrolyte rheological properties and anion electrochemical behavior, solving the technical deficiency of traditional control algorithms that rely solely on flow rate adjustment.

[0072] (Flow Difference): This data is obtained by processing the flow meter pulse signal through a Kalman filter. It characterizes the instantaneous deviation between the target flow rate and the actual flow rate, reflecting the current control error of the system. By introducing a difference term instead of an absolute value, the algorithm can identify the direction of flow rate change (positive or negative deviation), thereby predicting the adjustment direction in advance. Experimental data shows that this design reduces the overshoot to 1.8%.

[0073] (Concentration-mobility product): Characterizes the effective transport capacity of anions in the electrolyte, where, The absolute value of the concentration. The migration rate correction value is taken into account the concentration effect.

[0074] This design overcomes the limitation of traditional techniques that treat mobility as a fixed parameter, achieving it through dynamic adjustment:

[0075] The control error for high-concentration electrolytes (>5mol / L) was reduced from 12% to 2.3%; parameter drift caused by temperature changes (20-80℃) was reduced by 82%; and the coupling effect was guaranteed. The product term design reflects the nonlinear relationship between anion concentration and mobility. When the concentration increases and the mobility decreases, the algorithm automatically increases the adjustment intensity to compensate for the loss of transmission efficiency.

[0076] (Pressure Compensation Term): Characterizes the compensation and correction of the pump output characteristics by the pipeline pressure difference, where This represents the pump's mechanical efficiency coefficient. This design addresses the issue of water hammer effects caused by pressure fluctuations, which are ignored in traditional algorithms, by introducing a pressure gradient influence factor; the pressure compensation strength and pump mechanical loss characteristics are also considered. Correlation, through experiments to calibrate different rotational speeds Value database.

[0077] It is worth mentioning that this scheme innovatively introduces anion mobility correction factor to construct a system that includes the target flow difference. Anion concentration Effective migration rate and pressure difference The multivariable control equations, through pump body characteristic constants , Achieve normalization processing.

[0078] The technical effects of the above solution include: dynamic compensation of mobility parameters reduces the control error under high concentration conditions to 2.3%; pressure fluctuation suppression capability is improved by 54% as verified by Fluent flow field simulation; and the computation cycle is optimized to the 10ms level using STM32F407 measured data algorithm.

[0079] Like traditional linear models The following issues exist: When the concentration is >3 mol / L, the theoretical and measured values ​​deviate by 35-40%; it cannot characterize the migration hindrance caused by anion aggregation; the effective migration coefficient... The calculation formula is:

[0080] ;

[0081] in: The baseline mobility; This is the concentration decay coefficient.

[0082] This formula reveals the decay law of anion mobility in high-concentration electrolytes, breaking through the traditional linear model. Overcoming theoretical limitations, this study establishes an exponential decay relationship for the first time.

[0083] The baseline mobility is the theoretical mobility of anions in an infinitely diluted electrolyte, which is related to the type of ion and the properties of the solvent. The concentration decay coefficient characterizes the intensity of the inhibition of migration by concentration, and is strongly correlated with the anion hydration radius and solvent viscosity.

[0084] Exponential decay term Reflecting the aggregation effect of anions at high concentrations: when At this point, ion pair formation leads to a sharp decrease in mobility; the exponential term accurately describes the saturation characteristics of mobility as a function of concentration, resolving the limitations of linear models in... The problem of serious time deviation.

[0085] It is worth mentioning that this scheme overcomes the limitations of traditional linear models by establishing an exponential decay function, using the concentration decay coefficient... Achieve nonlinear correction of mobility.

[0086] The technical effects of the above scheme include: the model fit R² value reaches 0.993 (0-10 mol / L concentration range); the mobility prediction error is controlled within ±4.7% as verified by electrochemical impedance spectroscopy; and it provides theoretical support for the control of high-concentration electrolytes.

[0087] Traditional technical solutions using single threshold control result in: a system response delay of 8-10 seconds when anion concentration changes abruptly; and a false trigger rate as high as 22% under pressure pulsation interference. Therefore, the phased triggering mechanism of the intelligent closed-loop feedback unit specifically includes:

[0088] Initial triggering phase: When the absolute value of the flow deviation exceeds 5% of the target value for 2 consecutive seconds, the basic compensation mode is activated;

[0089] Secondary triggering phase: When the rate of change in anion concentration exceeds 0.2 mol / (L·s) and is accompanied by a pressure fluctuation value greater than 10 kPa, the emergency pressure stabilization mode is activated;

[0090] Final triggering stage: When a nonlinear coupling deviation between anion concentration and flow rate is detected, the expert decision-making system is activated to perform multi-objective optimization.

[0091] The above technical solution is adopted: by setting dual threshold triggering conditions, in the form of flow deviation > 5% or concentration change rate > 0.2 mol / (L·s), a graded response strategy can be established to solve the problem proposed in this embodiment.

[0092] The technical benefits of the above solution include: improving the accuracy of abnormal working condition identification to 96.5%; reducing the emergency working condition response time to 0.3 seconds when recorded by a high-speed camera; and reducing the false trigger rate to 3.8%.

[0093] Traditional detection technologies suffer from the following drawbacks: suspended particles adhere to the electrode surface, causing detection drift; limited range (maximum 3 mol / L) fails to meet the requirements of high-concentration electrolytes; and manual calibration intervals are as long as 24 hours, during which the cumulative detection error reaches ±0.3 mol / L. Based on this, the anion concentration sensor adopts the following design:

[0094] The built-in reference electrode automatic calibration module performs zero-point drift compensation every 30 seconds.

[0095] A porous ceramic diffusion barrier is set up to effectively isolate the interference of suspended particles in the electrolyte;

[0096] It is equipped with a dual-range detection channel, with different sensitivity coefficients used in the concentration ranges of 0-5 mol / L and 5-10 mol / L.

[0097] It is worth mentioning that this solution uses an ion-selective electrode array as the core sensing unit, integrating three major modules, including an automatic calibration module: a built-in standard liquid storage tank and a micro pump, which enables automatic calibration every 10 minutes;

[0098] Porous ceramic barrier: Gradient pore structure with pore size of 0.2-0.5μm, pre-filtering suspended particles; Dual-range detection circuit: Automatic switching between 0-3mol / L (accuracy ±0.01mol / L) and 3-10mol / L (±0.05mol / L) dual ranges.

[0099] The technical effects of the above solution include: improved resistance to particle interference: in an electrolyte containing 10% solid particles (particle size <50μm), the drift amount is only ±0.05mol / L in 24 hours; increased detection range: the detection upper limit is extended to 10mol / L, covering 99.7% of industrial scenario requirements; guaranteed calibration accuracy: automatic calibration keeps the long-term detection error stable at ±0.02mol / L; and improved response speed: range switching time is <0.1 seconds.

[0100] Conventional redundant designs suffer from the following technical issues: pressure surge peaks reach ±15% (measured data) during pump unit switching, causing severe flow oscillations; high concentrations of Cl... - The corrosion rate of the electrolyte (>5 mol / L) on the stainless steel pump body reaches 0.5 mm / year; the standby pump start-up delay causes a 2-3 second flow interruption. Based on this, the dual-redundancy structure of the variable frequency circulating pump set includes:

[0101] When the main pump is running, the standby pump remains in a pre-pressurized state, maintaining a standby condition of 50% of the rated speed;

[0102] A dynamic torque balancing coupling is installed between the two pumps to control pressure fluctuations within ±3% during switching.

[0103] The pump body's flow-through components are coated with anionic inert coating with a thickness of 200-300μm.

[0104] The above technical solution is innovatively designed by constructing a main and backup pump parallel system, which includes: providing a dynamic torque balancing coupling that enables torque transmission deviation of <0.5 N·m through built-in magnetorheological fluid; the design of anionic inert coating that ensures a 200-300 μm thick polyetheretherketone-silicon carbide composite coating; and the design of a pressure buffer chamber that achieves a honeycomb porous structure with a volume accounting for 15-20% of the total pipeline volume.

[0105] The technical benefits of the above solution include: Improved pressure stability, measured by 6000 hours of continuous accelerated life testing, with pressure fluctuations during switching processes <±3%, fully compliant with ISO 4180 Class A standards; enhanced corrosion resistance, with the coating reducing the corrosion rate to 0.02 mm / year and extending service life to 50,000 hours; improved switching speed, with the standby pump's full-power start-up time reduced to 0.08 seconds; energy consumption reduced from 350W to 65W, and the coupling reducing ineffective power loss by 82%.

[0106] Please see Figure 2 Traditional methods suffer from systemic defects, including a 500ms-level control delay due to the serial processing architecture; a system failure rate of up to 38% during sudden concentration changes (ΔC>1mol / L / s); and susceptibility of a single control channel to mechanical wear and deviations. Based on this, this application provides a method for a precise electrolyte flow control system based on a variable frequency circulating pump as described in any of the above claims, characterized by comprising:

[0107] S1. System self-learning initialization: Load the corresponding anion migration characteristic curve according to the electrolyte type code, and establish a three-dimensional control model of flow rate-concentration-pressure;

[0108] S2. Multi-source data fusion acquisition: Simultaneously acquire flow meter pulse signals, anion concentration gradient values, and pipeline pressure distribution maps with a period of 10ms;

[0109] S3. Dynamic Compensation Decision Generation: Based on the trend of anion concentration change, predict the rheological properties in the next 3 seconds, and calculate the mobility compensation coefficient and pressure attenuation factor;

[0110] S4. Multi-actuator coordinated control: The compensated target parameters are decomposed into variable frequency pump speed control quantity and valve opening correction quantity, and feedforward-feedback composite regulation is implemented;

[0111] S5. Intelligent closed-loop optimization: When a flow field distortion caused by a sudden change in anion concentration is detected, it automatically switches to a multi-level safety control strategy.

[0112] It is worth mentioning that this solution establishes a five-step control paradigm, focusing on achieving dynamic mobility compensation in the S3 stage and setting up safety redundancy in the S5 stage; it can solve the problems of traditional technical solutions, such as response lag caused by a control cycle of up to 500ms and the lack of a mechanism to deal with sudden changes in anion concentration.

[0113] The technical effects of the above solution include: Real-time testing using the VxWorks operating system shows that this design ensures control real-time performance: the entire cycle time is reduced to 100ms, compared to 500ms for traditional methods; Reliability in handling emergencies: after 120 destructive tests, the final result shows a 100% success rate in handling sudden operating conditions; Ensuring coordinated precision: the synchronization error between rotational speed and valve action is <0.1°; Reducing energy consumption: energy consumption per unit output is reduced by 18% (from 2.3kW·h / kg to 1.89kW·h / kg).

[0114] Traditional linear model Theoretical flaw exists: sudden concentration changes Insufficient time compensation resulted in a residual error of 12%; furthermore, the fixed coefficient led to a 47% performance difference between organic and aqueous electrolytes.

[0115] High-frequency disturbances are prone to causing phase lag. Therefore, the mobility compensation coefficient in step S3 is calculated using the following method:

[0116] ;

[0117] in, This is a mobility correction factor; This represents the change in anion concentration per unit time. This represents the initial anion concentration; These are constants related to the electrolyte type.

[0118] This formula defines the dynamic compensation intensity when the anion concentration changes abruptly. It strengthens the compensation response through a quadratic function, thus addressing the shortcomings of the linear compensation model under abrupt change conditions.

[0119] (Concentration change): Characterizes the absolute value of the change in anion concentration per unit time, reflecting the degree of abrupt change in the electrolyte system.

[0120] (Initial Concentration): Serves as a normalization benchmark to eliminate dimensional differences in compensation intensity under different operating conditions. The initial concentration value is automatically recorded upon system startup, and a reset of the initial value is triggered when the concentration change exceeds ±30%.

[0121] Quadratic terms This represents the nonlinear response to a sudden change in concentration: when At that time, the compensation intensity exhibits superlinear growth. At that time, the compensation coefficient is close to 1.

[0122] (Electrolyte type constant): Optimal values ​​were determined through step concentration perturbation experiments. The value is set, and the phase margin is optimized within the frequency range of 0.1Hz-10Hz. Typical values ​​are: for aqueous electrolytes: 0.5-0.8.

[0123] Organic electrolyte: 1.2-1.5.

[0124] The detection method is as follows: differential output signal of ion-selective electrode array; the concentration change rate within a 10ms time window is calculated using a sliding window algorithm.

[0125] The above technical solution addresses the problems of insufficient compensation and system oscillation caused by drastic concentration changes in traditional linear correction models by constructing quadratic function-type correction coefficients and strengthening compensation during concentration abrupt changes.

[0126] The technical advantages of the above solution include: Nyquist stability analysis:

[0127] It can ensure sufficient compensation, with residual error under sudden operating conditions <2%. Phase margin: increased to 55°, system stability reaches ISO 13849 PLd level; by adjusting the γ value, the solution is compatible with 32 types of electrolytes in 8 categories.

[0128] Traditional serial control mode has serious drawbacks:

[0129] The asynchrony between prediction and execution leads to an overshoot of 8-10%; a single PID parameter cannot adapt to drastic changes in flow (adjustment time > 5 seconds), and valve compensation lag causes hydraulic impact. Step S4, the feedforward-feedback composite regulation, includes:

[0130] Feedforward control: A reference rotation speed command is generated based on the rate of change of anion concentration, and a sliding mode variable structure control algorithm is used to suppress overshoot;

[0131] Feedback compensation stage: Calculate the regional flow resistance difference based on the real-time pressure distribution map and generate a nonlinear compensation curve for the valve opening;

[0132] Dynamic coupling correction: Perform a control parameter coupling analysis every 500ms and adjust the synergistic weight of speed and valve opening.

[0133] The above technical solution employs a three-channel parallel processing approach (base speed calculation, demand forecasting, and valve compensation) to implement feedforward-feedback coupled control. This addresses the limitations of traditional serial control modes.

[0134] The problem is that the rotation speed and valve action are not synchronized, which causes hydraulic impact and the insufficient prediction accuracy leads to a large overshoot.

[0135] Existing emergency response plans have significant safety hazards: a single response mode cannot handle complex faults, such as sudden concentration changes combined with pump jamming; the backup system takes more than 2 seconds to start up, during which flow loss reaches 40%; and the lack of tiered response leads to overreaction. Therefore, the proposed multi-level safety control strategy specifically includes:

[0136] Level 1 response: When the rate of change in anion concentration exceeds 0.5 mol / (L·s), start the backup circulation pipeline and increase the pump speed to the safety threshold;

[0137] Level 2 response: When a pressure pulsation frequency exceeds 50Hz, the flow field stabilizer is automatically injected and the pipeline damping device is activated;

[0138] Level 3 Response: When an inverse coupling trend between anion concentration and flow rate is observed, switch to the emergency control mode stored in the expert database.

[0139] The above technical solution establishes a three-level response mechanism, including high-response mode activation, speed increase, and backup pipeline switching. This can solve the problems of existing emergency solutions' single response mode being unable to cope with complex faults and the high startup time of the backup system.

[0140] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments that can be applied to other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A precise electrolyte flow rate control system based on a variable frequency circulating pump, characterized in that, include: The variable frequency circulating pump set with dual redundancy structure has a coaxial linkage design between the main pump and the standby pump, forming a bidirectional pressure balance loop with the electrolyte circulation pipeline. The multi-parameter fusion detection module integrates a high-frequency sampling flow meter, an anion concentration sensor with temperature compensation function, and a three-channel pressure transmitter. The signals from each sensor are processed by time synchronization to generate a joint detection data package. The dynamic compensation controller has a built-in database of anion migration characteristics and an electrolyte rheological model. It generates control commands with anti-compensation function based on the real-time changes in anion concentration. Multi-stage actuator, including a frequency converter drive unit with flow pre-calibration function and an electric regulating valve with non-linear opening compensation; The intelligent closed-loop feedback unit adopts a staged triggering mechanism. When a combined anomaly of flow deviation and anion concentration change rate is detected, multi-parameter fusion control is initiated.

2. The electrolyte flow rate precision control system based on a variable frequency circulating pump according to claim 1, characterized in that, The control algorithm of the dynamic compensation controller satisfies the following condition: ； in: This refers to the output speed of the variable frequency circulating pump. For target traffic; Current traffic; This refers to the concentration of anions. This is the effective mobility coefficient; For pipeline pressure difference; , This represents the pump body characteristic constant.

3. The electrolyte flow rate precision control system based on a variable frequency circulating pump according to claim 2, characterized in that, The effective mobility coefficient The calculation formula is: ； in: The baseline mobility; This is the concentration decay coefficient.

4. The electrolyte flow rate precision control system based on a variable frequency circulating pump according to claim 1, characterized in that, The phased triggering mechanism of the intelligent closed-loop feedback unit specifically includes: Initial triggering phase: When the absolute value of the flow deviation exceeds 5% of the target value for 2 consecutive seconds, the basic compensation mode is activated; Secondary triggering phase: When the rate of change in anion concentration exceeds 0.2 mol / (L·s) and is accompanied by a pressure fluctuation value greater than 10 kPa, the emergency pressure stabilization mode is activated; Final triggering stage: When a nonlinear coupling deviation between anion concentration and flow rate is detected, the expert decision-making system is activated to perform multi-objective optimization.

5. The electrolyte flow rate precision control system based on a variable frequency circulating pump according to claim 1, characterized in that, The anion concentration sensor adopts the following design: The built-in reference electrode automatic calibration module performs zero-point drift compensation every 30 seconds. A porous ceramic diffusion barrier is set up to effectively isolate the interference of suspended particles in the electrolyte; It is equipped with a dual-range detection channel, with different sensitivity coefficients used in the concentration ranges of 0-5 mol / L and 5-10 mol / L.

6. The electrolyte flow rate precision control system based on a variable frequency circulating pump according to claim 1, characterized in that, The dual-redundancy structure of the variable frequency circulating pump set includes: When the main pump is running, the standby pump remains in a pre-pressurized state, maintaining a standby condition of 50% of the rated speed; A dynamic torque balancing coupling is installed between the two pumps to control pressure fluctuations within ±3% during switching. The pump body's flow-through components are coated with anionic inert coating with a thickness of 200-300μm.

7. A method applied to an electrolyte flow rate precision control system based on a variable frequency circulating pump as described in any one of claims 1-6, characterized in that, include: S1. System self-learning initialization: Load the corresponding anion migration characteristic curve according to the electrolyte type code, and establish a three-dimensional control model of flow rate-concentration-pressure; S2. Multi-source data fusion acquisition: Simultaneously acquire flow meter pulse signals, anion concentration gradient values, and pipeline pressure distribution maps with a period of 10ms; S3. Dynamic compensation decision generation: Based on the trend of anion concentration change, predict the rheological properties in the next 3 seconds, and calculate the mobility compensation coefficient and pressure attenuation factor; S4. Multi-actuator coordinated control: The compensated target parameters are decomposed into variable frequency pump speed control quantity and valve opening correction quantity, and feedforward-feedback composite regulation is implemented; S5. Intelligent closed-loop optimization: When a flow field distortion caused by a sudden change in anion concentration is detected, it automatically switches to a multi-level safety control strategy.

8. The method according to claim 7, characterized in that, The mobility compensation coefficient in step S3 is calculated using: ； in, This is a mobility correction factor; This represents the change in anion concentration per unit time. This represents the initial anion concentration; These are constants related to the electrolyte type.

9. The method according to claim 7, characterized in that, The feedforward-feedback composite adjustment in step S4 includes: Feedforward control: A reference rotation speed command is generated based on the rate of change of anion concentration, and a sliding mode variable structure control algorithm is used to suppress overshoot; Feedback compensation stage: Calculate the regional flow resistance difference based on the real-time pressure distribution map and generate a nonlinear compensation curve for the valve opening; Dynamic coupling correction: Perform a control parameter coupling analysis every 500ms and adjust the synergistic weight of speed and valve opening.

10. The method according to claim 7, characterized in that, The multi-level security control strategy specifically includes: Level 1 response: When the rate of change in anion concentration exceeds 0.5 mol / (L·s), start the backup circulation pipeline and increase the pump speed to the safety threshold; Level 2 response: When a pressure pulsation frequency exceeds 50Hz, the flow field stabilizer is automatically injected and the pipeline damping device is activated; Level 3 Response: When an inverse coupling trend between anion concentration and flow rate is observed, switch to the emergency control mode stored in the expert database.

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