Accurate electrolyte flow regulation and control system and method based on variable-frequency circulating pump

Abstract

The invention relates to the technical field of hydrogen production, in particular to an electrolyte flow accurate regulation and control system and method based on a variable-frequency circulating pump. Comprising a frequency conversion circulating pump set with a dual-redundancy structure, and a main pump and a standby pump of the frequency conversion circulating pump set adopt coaxial linkage design and form a bidirectional pressure balance loop with an electrolyte circulating pipeline; the multi-parameter fusion detection module is integrated with a high-frequency sampling flowmeter, an anion concentration sensor with a temperature compensation function and a three-channel pressure transmitter, and signals of all the sensors are subjected to time synchronization processing to generate a joint detection data packet; the dynamic compensation controller is internally provided with an anion migration characteristic database and an electrolyte rheology model, and generates a control instruction with an advanced compensation function according to the real-time anion concentration variable quantity; the multi-physical-field parameter change of the electrolyte can be sensed in real time, the control instruction is dynamically corrected, and the anti-interference capability is high.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen production, and particularly to an electrolyte flow rate precise regulation system and method based on a variable frequency circulation pump. Background Art

[0002] Through in-depth research on the existing technologies in the field of electrolyte control, it is found that there are serious technical bottlenecks in the current electrolyte flow rate regulation system when dealing with complex working conditions such as high concentration, multi-phase state, and strong corrosion. Traditional technical solutions mostly perform linear regulation based on single physical field parameters and cannot meet the core requirements of modern industrial precision electrolysis processes. Specifically: the following key defects mainly exist in the existing technologies: Parameter detection lag: Conventional systems adopt a split sensor architecture, and there is a millisecond-level time difference in the acquisition of key parameters such as flow rate, concentration, and pressure. When the anion concentration of the electrolyte suddenly changes, the response delay of the control system causes the flow rate overshoot to reach 8 - 12%, seriously affecting the hydrogen production effect. Simplification and distortion of the control model: Mainstream control algorithms regard the anion mobility as a fixed parameter and ignore the non-linear influence of concentration changes on ion transport efficiency. Experiments show that when the electrolyte concentration exceeds 3 mol / L, the flow rate control error of the traditional model increases exponentially. Weak anti-interference ability of the system: The existing technologies lack effective treatment of the coupling effect between the rheological characteristics of the electrolyte and the mechanical actuator, resulting in: the water hammer effect caused by pressure fluctuations causes flow rate oscillations; the interference of suspended particles causes concentration detection drift.

[0003] The pressure shock during pump group switching causes cascading control disorders. The above problems seriously restrict the application of the electrolyte process in hydrogen production, and there is an urgent need for a flow rate regulation technical solution that can real-time sense the changes of multi-physical field parameters of the electrolyte, dynamically correct control instructions, and has strong anti-interference ability. Summary of the Invention

[0004] The purpose of the present invention is to solve the disadvantages existing in the prior art, and a precise electrolyte flow rate regulation system based on a variable frequency circulation pump is proposed, including: A variable frequency circulation pump group with a dual redundant structure, whose main pump and standby pump adopt a coaxial linkage design and form a two-way pressure balance loop with the electrolyte circulation pipeline; A multi-parameter fusion detection module, integrating a high-frequency sampling flowmeter, an anion concentration sensor with temperature compensation function, and a three-channel pressure transmitter. The signals of each sensor are processed by time synchronization to generate a combined detection data packet; A dynamic compensation controller, built-in with an anion migration characteristic database and an electrolyte rheology model, and generating a control instruction with an advanced compensation function according to the real-time change amount of the anion concentration; A multi-stage actuator, including a variable frequency drive unit with a flow rate pre-calibration function and an electric control valve with non-linear opening compensation; The intelligent closed-loop feedback unit adopts a phased triggering mechanism and starts multi-parameter fusion regulation when a composite anomaly of flow deviation and anion concentration change rate is detected.

[0005] Adopting the above technical solution: This solution constructs a five-module collaborative control system. The variable-frequency pump group is used as the execution terminal. The multi-parameter detection module realizes the synchronous acquisition of flow rate, anion concentration, and pressure. The dynamic control module generates instructions based on the electrochemical compensation algorithm. The execution module realizes the dual-channel regulation of rotational speed and valve. The closed-loop feedback module establishes a deviation triggering mechanism. It can solve the problems in the existing technology, such as the feedback delay of anion concentration change caused by single-sensor detection, the lack of consideration of the electrochemical parameter coupling effect in the control algorithm, and the dependence on manual intervention for fault recovery.

[0006] Preferably, the control algorithm of the dynamic compensation controller satisfies the following conditional formula: ; Where: is the output rotational speed of the variable-frequency circulating pump; is the target flow rate; is the current flow rate; is the anion concentration; is the effective mobility coefficient; is the pipeline pressure difference; , is the pump body characteristic constant.

[0007] Adopting the above technical solution: This solution innovatively introduces an anion mobility correction factor and constructs a multi-variable control equation including the target flow rate difference , anion concentration , effective mobility and pressure difference . Through the pump body characteristic constant , realizes normalization processing.

[0008] Further preferably, the calculation formula of the effective mobility coefficient is: ; Where: is the reference mobility; is the concentration attenuation coefficient.

[0009] Adopting the above technical solution: This solution breaks through the limitations of the traditional linear model by establishing an exponential decay function and realizes the non-linear correction of mobility through the concentration attenuation coefficient .

[0010] Further preferably, the phased triggering mechanism of the intelligent closed-loop feedback unit specifically includes: Primary triggering stage: 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 stage: When the change rate of the anion concentration exceeds 0.2 mol / (L·s) and is accompanied by a pressure fluctuation value greater than 10 kPa, the emergency voltage stabilization mode is activated; Final triggering stage: When a non-linear coupling deviation between the anion concentration and the flow value is detected, the expert decision-making system is started for multi-objective optimization.

[0011] Adopting the above technical solution: This solution can establish a hierarchical response strategy by setting double-threshold triggering conditions (flow deviation > 5% or concentration change rate > 0.2 mol / (L·s)).

[0012] Further preferably, the anion concentration sensor adopts the following design: Built-in reference electrode automatic calibration module, which performs zero drift compensation every 30 seconds; Set a porous ceramic diffusion barrier to effectively isolate the interference of suspended particles in the electrolyte; Configure a dual-range detection channel, and adopt different sensitivity coefficients in the concentration ranges of 0 - 5 mol / L and 5 - 10 mol / L respectively.

[0013] Adopting the above technical solution: This solution adopts an ion-selective electrode array, integrating three innovative designs: automatic calibration, porous ceramic barrier, and dual-range detection.

[0014] Further preferably, the dual-redundant structure of the variable-frequency circulating pump group includes: When the main pump is running, the standby pump maintains a pre-pressurized state and maintains a standby condition with a rated speed of 50%; A dynamic torque balance coupling is set between the two pumps, and the pressure fluctuation is controlled within ±3% during switching; The over-current components of the pump body are coated with an anion-inert coating with a thickness of 200 - 300 μm.

[0015] Adopting the above technical solution: This solution can solve the problems of excessive pressure shock during pump switching and shortened pump body life caused by anion corrosion in conventional redundant designs through the parallel design of the main and standby pumps, the adoption of a dynamic torque balance coupling, and the coating of over-current components with an anion-inert coating.

[0016] A method, applied to an electrolyte flow precise regulation system based on a variable-frequency circulating pump as described in any one of the above, is characterized by including: S1. System self-learning initialization: According to the electrolyte type code, load the corresponding anion migration characteristic curve and establish a three-dimensional control model of flow-concentration-pressure; S2. Multi-source data fusion acquisition: Synchronously obtain the flowmeter pulse signal, anion concentration gradient value, and pipeline pressure distribution map every 10 ms; S3. Dynamic compensation decision generation: Predict the rheological properties within the next 3 seconds based on the change trend of anion concentration, and calculate the mobility compensation coefficient and pressure attenuation factor; S4. Multi-actuator collaborative control: Decompose the compensated target parameters into the control quantity of the variable-frequency pump speed and the correction quantity of the valve opening, and implement feedforward-feedback composite regulation; S5. Intelligent closed-loop optimization: When a flow field distortion caused by an abrupt change in anion concentration is detected, automatically switch to a multi-level safety control strategy.

[0017] Adopting the above technical solution: This solution realizes dynamic compensation of mobility mainly in the S3 stage and sets up safety redundancy in the S5 stage by establishing a five-step control paradigm; it can solve the problems of the traditional technical solution, such as the control period being as long as 500 ms, resulting in response lag and lacking a mechanism to cope with abrupt changes in anion concentration.

[0018] Further preferably, the calculation of the mobility compensation coefficient in step S3 adopts: ; where, is the mobility correction coefficient; is the change amount of anion concentration per unit time; is the initial anion concentration; is the constant related to the electrolyte type.

[0019] Adopting the above technical solution: This solution constructs a quadratic function type correction coefficient and strengthens the compensation intensity during concentration mutation; it can solve the problems of insufficient compensation during drastic concentration changes and easy system oscillation existing in the traditional linear correction model.

[0020] Further preferably, the feedforward-feedback composite regulation in step S4 includes: Feedforward control link: Generate a reference speed command based on the change rate of anion concentration, and use the sliding mode variable structure control algorithm to suppress overshoot; Feedback compensation link: Calculate the regional flow resistance difference according to the real-time pressure distribution map, and generate a non-linear compensation curve for the valve opening; Dynamic coupling correction: Perform a control parameter coupling degree analysis every 500 ms, and adjust the collaborative action weight of the speed and the valve opening.

[0021] Adopting the above technical solution: This solution implements feedforward-feedback coupling control through three-channel parallel processing (basic speed calculation, demand prediction, valve compensation). It can solve the problems existing in the traditional serial control mode: Problems such as hydraulic shock caused by the asynchronous rotation speed and valve action and large overshoot caused by insufficient prediction accuracy.

[0022] Further preferably, the multi-level safety control strategy specifically includes: First-level response: When the change rate of anion concentration exceeds 0.5 mol / (L·s), start the standby circulation pipeline and increase the pump group speed to the safety threshold; Second-level response: When the detected pressure pulsation frequency exceeds 50 Hz, automatically inject a flow field stabilizer and activate the pipeline damping device; Third-level response: When there is an inverse coupling trend between the anion concentration and the flow rate value, switch to the emergency control mode stored in the expert database.

[0023] Adopting the above technical solution: This solution establishes a three-level response mechanism, including high-response mode activation, speed increase, and standby pipeline switching, which can solve the problems that the single-response mode of the existing emergency plan cannot handle complex faults and the startup time of the standby system is relatively high. Description of the Drawings

[0024] Figure 1 It is a block diagram of an electrolyte flow rate precise regulation system based on a variable-frequency circulation pump according to the present application; Figure 2 It is a flowchart of a method for precisely regulating the electrolyte flow rate based on a variable-frequency circulation pump according to the present application. Detailed Embodiment

[0025] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0026] Please refer to Figure 1 , the traditional electrolyte control system has the following technical defects: single-sensor detection leads to a feedback delay in the change of anion concentration (about 3-5 seconds); the control algorithm does not consider the coupling effect of electrochemical parameters; fault recovery depends on manual intervention. Based on this, an electrolyte flow rate precise regulation system based on a variable-frequency circulation pump proposed in the present application includes: A variable-frequency circulation pump group with a dual-redundancy structure, whose main pump and standby pump adopt a coaxial linkage design, and form a two-way pressure balance loop with the electrolyte circulation pipeline; A multi-parameter fusion detection module, which integrates a high-frequency sampling flowmeter, an anion concentration sensor with temperature compensation function, and a three-channel pressure transmitter. The signals of each sensor are processed by time synchronization to generate a combined detection data packet; Dynamic compensation controller, built-in with a database of anion migration characteristics and an electrolyte rheology model, generates control instructions with an advanced compensation function based on the real-time change in anion concentration; Multi-stage actuator, including a variable-frequency drive unit with a flow pre-calibration function and an electric control valve with a non-linear opening compensation; Intelligent closed-loop feedback unit, adopting a phased trigger mechanism, and starts multi-parameter fusion regulation when detecting a composite anomaly of flow deviation and anion concentration change rate.

[0027] It is worth mentioning that: This solution constructs a five-module collaborative control system. Using a variable-frequency pump group as the execution terminal, the multi-parameter detection module realizes the synchronous acquisition of flow rate, anion concentration, and pressure. The dynamic control module generates instructions based on the electrochemical compensation algorithm. The execution module realizes the dual-channel regulation of speed and valve. The closed-loop feedback module establishes a deviation trigger mechanism. It can solve the problems in the existing technology, including the feedback delay of anion concentration change caused by single-sensor detection; the control algorithm does not consider the coupling effect of electrochemical parameters; and the problem that fault recovery depends on manual intervention.

[0028] The technical effects of the above embodiments include: It can shorten the detection response time; improve the flow control accuracy; and ensure the success rate of system fault self-recovery.

[0029] For example, the existing technology uses fixed mobility parameters, resulting in: Under the condition of high-concentration electrolyte, the flow deviation reaches 8 - 12%; and the pressure fluctuation causes a chain reaction of control disorders. Based on this, the control algorithm of the dynamic compensation controller satisfies the following conditional formula: ; Where: is the output speed of the variable-frequency circulation pump; is the target flow rate; is the current flow rate; is the anion concentration; is the effective mobility coefficient; is the pipeline pressure difference; , is the pump body characteristic constant.

[0030] The above formula is the core algorithm of the dynamic control module, which first couples the anion migration characteristics with the hydrodynamic parameters. The formula is constructed based on the synergistic action principle of electrolyte rheology characteristics and anion electrochemical behavior, solving the technical defect of only relying on single-factor regulation of flow rate in traditional control algorithms; (Flow difference): Obtained after the data of the flowmeter pulse signal is processed by Kalman filtering, it represents the instantaneous deviation value between the target flow and the actual flow, reflecting the current control error of the system. By introducing the difference term instead of the absolute value, the algorithm can identify the direction of flow change (positive deviation or negative deviation), so as to anticipate the adjustment direction in advance. Experimental data shows that this design reduces the overshoot to 1.8%; (Concentration-mobility product term): Represents the effective transport ability of anions in the electrolyte. Among them, is the absolute value of the concentration, is the mobility correction value considering the concentration effect.

[0031] This design can break through the limitation of traditional technologies that regard mobility as a fixed parameter, and achieve through dynamic correction: For high-concentration electrolytes (>5mol / L), the control error is reduced from 12% to 2.3%; the parameter drift caused by temperature changes (20-80°C) is reduced by 82%; and the coupling effect can be guaranteed. The product term design reflects the non-linear 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 transport efficiency.

[0032] (Pressure compensation term): Represents the compensation and correction of the pipeline pressure difference on the output characteristics of the pump body. Among them, is the mechanical efficiency coefficient of the pump body. This design solves the problem of water hammer effect caused by ignoring pressure fluctuations in traditional algorithms by introducing a pressure gradient influence factor; the pressure compensation intensity is related to the mechanical loss characteristics of the pump body and calibrates the value database at different rotational speeds through experiments.

[0033] It is worth mentioning that: this scheme innovatively introduces an anion mobility correction factor, constructs a multivariable control equation including the target flow difference , anion concentration , effective mobility and pressure difference , and realizes normalization processing through the pump body characteristic constant .

[0034] The technical effects of the above scheme include: the dynamic compensation of the mobility parameter reduces the control error in high-concentration working conditions to 2.3%; the ability to suppress pressure fluctuations is improved by 54% through Fluent flow field simulation verification; the operation cycle of the algorithm is optimized to the 10ms level through the measured data of STM32F407.

[0035] Such as the traditional linear model There exists: when the concentration > 3 mol / L, the deviation between the theoretical value and the measured value reaches 35 - 40%; it is unable to characterize the migration retardation phenomenon caused by the anion aggregation effect; the effective mobility coefficient The calculation formula is: ; Where: is the reference mobility; is the concentration attenuation coefficient.

[0036] This formula reveals the attenuation law of anion mobility in high-concentration electrolytes, breaking through the theoretical limitations of the traditional linear model and establishing an exponential attenuation relationship for the first time.

[0037] The reference mobility can achieve the theoretical mobility of anions in infinitely diluted electrolytes and is related to the ion species and solvent characteristics. The concentration attenuation coefficient characterizes the inhibition intensity of concentration on mobility and is strongly related to the anion hydration radius and solvent viscosity.

[0038] The exponential attenuation term reflects the aggregation effect of anions at high concentrations: when , the formation of ion pairs leads to a sharp decrease in mobility; the exponential term accurately describes the saturation characteristics of mobility with respect to concentration, solving the serious deviation problem of the linear model at .

[0039] It is worth mentioning that: this solution breaks through the limitations of the traditional linear model by establishing an exponential attenuation function and realizes the non-linear correction of mobility through the concentration attenuation coefficient .

[0040] The technical effects of the above solution include: the model fitting degree R² value reaches 0.993 (in the concentration range of 0 - 10 mol / L); the mobility prediction error verified by electrochemical impedance spectroscopy is controlled within ±4.7%; it provides a theoretical support for the control of high-concentration electrolytes.

[0041] For example, the single-threshold control of the traditional technical solution leads to: when the anion concentration changes suddenly, the system response delay is 8 - 10 seconds; under the interference of pressure pulsation, the false trigger rate is as high as 22%; based on this, the phased trigger mechanism of the intelligent closed-loop feedback unit specifically includes: Primary trigger stage: when the absolute value of the flow deviation exceeds 5% of the target value for 2 consecutive seconds, start the basic compensation mode; Secondary trigger stage: when the change rate of anion concentration exceeds 0.2 mol / (L·s) and is accompanied by a pressure fluctuation value greater than 10 kPa, activate the emergency voltage stabilization mode; Final triggering stage: When a non-linear coupling deviation between the anion concentration and the flow rate value is detected, the expert decision-making system is activated for multi-objective optimization.

[0042] Adopting the above technical solution: By setting double-threshold triggering conditions in the form of flow rate deviation > 5% or concentration change rate > 0.2 mol / (L·s), this solution can establish a hierarchical response strategy to solve the problems proposed in this embodiment.

[0043] The technical effects of the above solution include: The recognition accuracy of abnormal working conditions is increased to 96.5%; The emergency working condition response time is shortened to 0.3 seconds under the recording of a high-speed camera; The false triggering rate is reduced to 3.8%.

[0044] Traditional detection technologies have the following technical defects: Suspended particles adhering to the electrode surface cause detection drift; The measurement range is limited (maximum 3 mol / L) and cannot meet the requirements of high-concentration electrolyte; The manual calibration interval is as long as 24 hours, and the detection error accumulates up to ±0.3 mol / L during this period. Based on this, the anion concentration sensor adopts the following design: Built-in reference electrode automatic calibration module, which performs zero drift compensation every 30 seconds; Set a porous ceramic diffusion barrier to effectively isolate the interference of suspended particles in the electrolyte; Configure a dual-range detection channel, and different sensitivity coefficients are adopted in the concentration ranges of 0 - 5 mol / L and 5 - 10 mol / L respectively.

[0045] It is worth mentioning that this solution uses an ion-selective electrode array as the core sensing unit, integrating three major modules. The automatic calibration module: Built-in standard solution storage tank and micro pump, realizing automatic calibration every 10 minutes; The porous ceramic barrier: A gradient pore structure with a pore diameter of 0.2 - 0.5 μm, pre-filtering suspended particles; The dual-range detection circuit: Set dual-range automatic switching of 0 - 3 mol / L (accuracy ±0.01 mol / L) and 3 - 10 mol / L (±0.05 mol / L).

[0046] The technical effects of the above solution include: It can improve the anti-particle interference ability: In an electrolyte containing 10% solid particles (particle size < 50 μm), the drift amount in 24 hours is only ±0.05 mol / L; Increase the detection range, and the detection upper limit is extended to 10 mol / L, covering 99.7% of industrial scenario requirements; Ensure calibration accuracy, and the automatic calibration makes the long-term detection error stable at ±0.02 mol / L; Improve the response speed: The range switching time is < 0.1 second.

[0047] Conventional redundancy designs have the following technical problems. When the pump group switches, the peak pressure shock reaches ±15% (measured data), causing violent flow rate fluctuations; High-concentration Cl- The corrosion rate of the electrolyte (>5mol / L) on the stainless steel pump body reaches 0.5mm / year; the start-up delay of the standby pump causes a 2 - 3 second flow interruption. Based on this, the dual-redundancy structure of the variable-frequency circulating pump group includes: When the main pump is running, the standby pump maintains a pre-pressurized state, maintaining a standby condition at 50% of the rated speed; A dynamic torque balance coupling is set between the two pumps, and the pressure fluctuation during switching is controlled within ±3%; The flow-through components of the pump body adopt an anion-inert coating with a thickness of 200 - 300μm.

[0048] Adopting the above technical solutions: This solution constructs a parallel system of the main and standby pumps, innovatively including: providing a dynamic torque balance coupling, which can achieve a torque transmission deviation <0.5N·m with the built-in magnetorheological fluid; the design of the anion-inert coating can ensure a polyether ether ketone-silicon carbide composite coating with a thickness of 200 - 300μm; the design of the pressure buffer chamber realizes a honeycomb-like porous structure, and the volume accounts for 15 - 20% of the total pipeline volume.

[0049] The technical effects of the above solution include: Measured by a 6000-hour continuous operation accelerated life test, this design has improved pressure stability, the pressure fluctuation during the switching process <±3%, fully meeting the ISO 4180 Class A standard; it has improved corrosion resistance, the coating reduces the corrosion rate to 0.02mm / year, and the service life is extended to 50,000 hours; it ensures the switching speed: the full-power start-up time of the standby pump is shortened to 0.08 seconds; the energy consumption is reduced from 350W to 65W, and the coupling reduces the ineffective power loss by 82%.

[0050] Please refer to Figure 2 , for example, the traditional method has systematic defects: including a 500ms-level control delay caused by the serial processing architecture; the system failure rate reaches 38% when there is a sudden concentration change (ΔC>1mol / L / s); a single control channel is easily affected by mechanical wear deviation. Based on this, this application provides a method, which is applied to an electrolyte flow rate precise regulation system based on a variable-frequency circulating pump as described in any one of the above, and is characterized by including: 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: Synchronously obtain the flowmeter pulse signal, anion concentration gradient value, and pipeline pressure distribution map every 10ms; S3. Dynamic compensation decision generation: Predict the rheological characteristics within the next 3 seconds according to the change trend of the anion concentration, and calculate the migration rate compensation coefficient and pressure attenuation factor; S4. Cooperative control of multiple actuators: Decompose the compensated target parameters into the control quantity of the variable-frequency pump speed and the correction quantity of the valve opening, and implement feedforward-feedback composite regulation. S5. Intelligent closed-loop optimization: When a flow field distortion caused by a sudden change in anion concentration is detected, automatically switch to a multi-level safety control strategy.

[0051] It is worth mentioning that: By establishing a five-step control paradigm, this solution focuses on achieving dynamic compensation of the mobility in the S3 stage and setting up safety redundancy in the S5 stage; it can solve the problems of the traditional technical solution, such as the control cycle being as long as 500 ms, resulting in response lag, and lacking a mechanism to cope with sudden changes in anion concentration.

[0052] The technical effects of the above solution include: Measured by the real-time operating system (VxWorks), this design can ensure control real-time performance: the full-cycle time is compressed to 100 ms; while the traditional method is 500 ms; disposal reliability: after 120 groups of destructive tests, the final result is that the success rate of handling sudden operating conditions is 100%; ensure cooperative accuracy: the synchronization error between the speed and the valve action is <0.1°; reduce the energy consumption index: the energy consumption per unit output is reduced by 18% (from 2.3 kW·h / kg to 1.89 kW·h / kg).

[0053] Traditional linear model There are theoretical defects: insufficient compensation during sudden concentration changes, with a residual error of up to 12%; and the fixed coefficient results in a performance difference of 47% between organic / aqueous electrolytes; High-frequency disturbances are prone to causing phase lags. Based on this, the calculation of the mobility compensation coefficient in step S3 adopts: ; Among them, is the mobility correction coefficient; is the change amount of anion concentration per unit time; is the initial anion concentration; is a constant related to the electrolyte type.

[0054] This formula defines the dynamic compensation intensity when the anion concentration changes suddenly, and strengthens the compensation response through a quadratic function to solve the deficiencies of the linear compensation model under sudden operating conditions.

[0055] (Change amount of concentration): Represents the absolute value of the change in anion concentration per unit time, reflecting the degree of mutation of the electrolyte system.

[0056] (Initial concentration): As a normalization benchmark, it eliminates the dimensional difference in compensation intensity under different operating conditions. The initial concentration value is automatically recorded when the system starts, and the initial value is reset when the concentration change exceeds ±30%.​

[0057] Quadratic term Indicates the non - linear response to concentration mutation: When happens, the compensation intensity shows super - linear growth, when, the compensation coefficient is close to 1.

[0058] (Electrolyte type constant): Determine the optimal value through step - change concentration perturbation experiment, and optimize the phase margin in the frequency range of 0.1Hz - 10Hz. Typical values are as follows: for aqueous electrolytes: 0.5 - 0.8 ; for organic electrolytes: 1.2 - 1.5. The detection method is: the differential output signal of the ion - selective electrode array; use the sliding - window algorithm to calculate the concentration change rate within a 10 - ms time window.

[0059] Adopt the above - mentioned technical solution: This solution constructs a quadratic - function - type correction coefficient and strengthens the compensation intensity during concentration mutation; it can solve the problems of insufficient compensation during drastic concentration changes and easy system oscillation existing in the traditional linear correction model.

[0060] The technical effects of the above - mentioned solution include: Through Nyquist stability analysis:

[0061] It can ensure sufficient compensation, and the residual error under mutation conditions is <2% ; Phase margin: increased to 55°, and the system stability reaches ISO 13849 PLd level; through γ - value adjustment, the solution is compatible with 32 electrolytes of 8 categories. The traditional serial control mode has serious defects:

[0062] The asynchrony between prediction and execution leads to an overshoot of 8 - 10%; a single PID parameter cannot adapt to drastic flow changes (regulation time > 5 seconds) and the valve compensation lag causes hydraulic shock. The feed - forward - feedback composite regulation in step S4 includes: Feed - forward control link: Generate a reference speed command based on the anion concentration change rate, and use the sliding - mode variable - structure control algorithm to suppress overshoot; Feedback compensation link: Calculate the regional flow - resistance difference according to the real - time pressure distribution map, and generate a non - linear compensation curve for valve opening; Dynamic coupling correction: Perform a control - parameter coupling - degree analysis every 500ms to adjust the cooperation weight of the rotational speed and valve opening. Adopt the above - mentioned technical solution: This solution performs three - channel parallel processing (basic rotational - speed calculation, demand prediction, valve compensation) and implements feed - forward - feedback coupling control. It can solve the problems existing in the traditional serial control mode:

[0063] Problems such as hydraulic shock caused by the asynchronous rotation speed and valve action, and large overshoot caused by insufficient prediction accuracy.

[0064] For example, there are major safety hazards in the existing emergency plans: the single response mode cannot handle compound faults, such as concentration mutation + pump jamming; the start-up time of the standby system is > 2 seconds, and the flow loss during this period reaches 40%; the lack of hierarchical response leads to overreaction. Based on this, the multi-level safety control strategy specifically includes: First-level response: When the change rate of anion concentration exceeds 0.5 mol / (L·s), start the standby circulation pipeline and increase the pump group speed to the safety threshold; Second-level response: When the detected pressure pulsation frequency exceeds 50 Hz, automatically inject the flow field stabilizer and activate the pipeline damping device; Third-level response: When there is an inverse coupling trend between the anion concentration and the flow rate value, switch to the emergency control mode stored in the expert database.

[0065] Adopting the above technical solutions: This solution establishes a three-level response mechanism, including the activation of a high-response mode, speed increase, and standby pipeline switching, which can solve the problems that the single response mode of the existing emergency plan cannot handle complex faults and the start-up time of the standby system is relatively high.

[0066] The above are only the preferred embodiments of the present invention, and do not limit the present invention in other forms. Any person skilled in the art may use the disclosed technical content to make changes or modifications into equivalent embodiments with equivalent changes and apply them to other fields. However, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention without departing from the technical solution content of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. An electrolyte flow precision control system based on a variable frequency circulation pump, characterized in that: include: The variable frequency circulating pump group with dual redundant structure, its main pump and standby pump adopt coaxial linkage design, forming a two-way pressure balance circuit 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 of each sensor are processed by time synchronization to generate a joint detection data packet; Dynamic compensation controller, with built-in anion migration characteristics database and electrolyte rheology model, generates control instructions with advance compensation function according to real-time anion concentration changes; Multi-stage actuator, including variable frequency drive unit with flow pre-calibration function and electric control valve with non-linear opening compensation; The intelligent closed-loop feedback unit adopts a staged trigger mechanism and starts multi-parameter fusion control when a combined anomaly of flow deviation and anion concentration change rate is detected.

2. According to claim 1, a precise control system for electrolyte flow based on a variable frequency circulation pump is characterized in that: The control algorithm of the dynamic compensation controller satisfies the following conditional formula: ； in: Output speed of variable frequency circulating pump; is the target flow; is the current flow; is the anion concentration; is the effective mobility coefficient; is the pipeline pressure difference; , is the pump characteristic constant.

3. According to claim 2, a precise control system for electrolyte flow based on a variable frequency circulation pump is characterized in that: The effective mobility coefficient The calculation formula is: ； in: is the baseline migration rate; is the concentration attenuation coefficient.

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

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

6. The electrolyte flow precision control system based on a variable frequency circulation pump according to claim 1 is characterized in that: The dual redundant structure of the variable frequency circulating pump group includes: When the main pump is running, the standby pump remains in a pre-pressurized state and maintains a standby operating condition of 50% of the rated speed; A dynamic torque balancing coupling is installed between the two pumps, and the pressure fluctuation is controlled within ±3% during switching; The pump body flow-through parts adopt anionic inert coating with a thickness of 200-300μm.

7. A method, applied to an electrolyte flow precision control system based on a variable frequency circulation pump as described in any one of claims 1 to 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-concentration-pressure; S2. Multi-source data fusion acquisition: synchronously acquire the flow meter pulse signal, anion concentration gradient value, and pipeline pressure distribution map with a period of 10ms; S3. Dynamic compensation decision generation: predict the rheological properties within the next 3 seconds based on the trend of anion concentration changes, and calculate the mobility compensation coefficient and pressure attenuation factor; S4. Multi-actuator collaborative control: decompose the compensated target parameters into variable frequency pump speed control quantity and valve opening correction quantity, and implement feedforward-feedback composite regulation; S5. Intelligent closed-loop optimization: When 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, is the mobility correction factor; is the change in anion concentration per unit time; is the initial anion concentration; is a constant related to the electrolyte type.

9. The method according to claim 7, characterized in that: The feedforward-feedback composite regulation in step S4 comprises: Feedforward control link: Generate a reference speed command based on the rate of change of anion concentration, and use a sliding mode variable structure control algorithm to suppress overshoot; Feedback compensation link: Calculate regional flow resistance differences based on real-time pressure distribution maps and generate nonlinear compensation curves for valve opening; Dynamic coupling correction: Perform control parameter coupling analysis every 500ms to 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 of anion concentration exceeds 0.5 mol / (L·s), the backup circulation pipeline is started and the pump speed is increased to the safety threshold; Secondary response: When the pressure pulsation frequency is detected to be over 50Hz, the flow field stabilizer is automatically injected and the pipeline damping device is activated; Level 3 response: When there is a reverse coupling trend between the anion concentration and the flow value, switch to the emergency control mode stored in the expert database.

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