A flow control method and system for an equal percentage characteristic flow regulating valve

Abstract

This application proposes a flow control method and system for an equal percentage characteristic flow regulating valve, relating to the field of flow control technology. The method includes: determining an initial opening command by looking up a table and controlling the opening to obtain a first opening; regulating the flow based on the first opening to obtain a first flow value and a first flow deviation between the first flow value and a target flow value; if the first flow deviation is greater than a second target value, determining an opening compensation amount based on external disturbance factors, and obtaining a target opening based on the opening compensation amount and the first opening; if the first flow deviation is less than or equal to the second target value, determining an optimized flow based on the compensated opening. By setting a multi-disturbance identification mechanism based on four compensation factors and priority determination, this application achieves strong adaptability to complex dynamic environments under low flow or rapidly changing operating conditions, effectively overcoming the adaptability limitations of traditional control methods due to their reliance on fixed parameters.

Description

Technical Field

[0001] This application relates to the field of flow control technology, and in particular to a flow control method and system for an equal percentage characteristic flow regulating valve. Background Technology

[0002] In the field of industrial process control, equal percentage characteristic flow control valves are widely used in fluid control systems requiring wide-range adjustment and high stability. These valves exhibit a non-linear relationship between opening degree and flow rate; that is, as the opening degree increases, the flow rate change caused by a unit change in opening degree increases exponentially. This provides fine adjustment capability at small opening degrees and sufficient flow capacity at large opening degrees. Traditional flow control methods typically calculate the corresponding theoretical opening degree based on a set target flow rate value through table lookup or mathematical models, and then drive the valve to that opening position. Subsequently, the control system dynamically adjusts the valve opening using a proportional-integral-derivative (PID) control algorithm based on the deviation between the real-time flow rate value fed back from the flow sensor and the target value, in order to reduce or eliminate the deviation.

[0003] However, in actual operation, various external disturbances can significantly affect the flow control accuracy of valves. For example, changes in medium temperature may alter fluid density and viscosity, thus affecting the actual flow rate; fluctuations in inlet pressure directly change the pressure difference across the valve, disrupting the original flow-opening relationship; vibrations in the pipeline system may cause flow measurement noise or valve position drift; furthermore, long-term operation can alter the frictional characteristics between the valve stem and packing, leading to sluggish or incomplete actuator response. These disturbances make it difficult to achieve high-precision flow regulation solely through theoretical opening settings and conventional feedback control, especially under low flow or rapidly changing operating conditions, which can easily result in response lag, overshoot, oscillation, or even regulation failure. To improve control performance, existing technologies typically rely on increasing sensor accuracy, optimizing PID parameters, or adding feedforward compensation. However, these methods often have limited adaptability to specific operating conditions and lack the ability to comprehensively identify and coordinate multiple disturbances, resulting in significant deficiencies in the system's robustness and regulation accuracy under complex operating conditions. Summary of the Invention

[0004] This application aims to at least partially address one of the technical problems in the related art.

[0005] To achieve the above objectives, this application proposes a flow control method for an equal percentage characteristic flow regulating valve, comprising the following steps:

[0006] Step 1: Determine the target traffic value and the real-time traffic value;

[0007] Step 2: Determine the flow deviation based on the target flow value and the real-time flow value;

[0008] Step 3: Preset a first target value, determine a first judgment condition based on the first target value, when the real-time flow value cannot meet the first judgment condition, determine the initial opening instruction by looking up the table and control the opening to obtain the first opening, regulate the flow based on the first opening to obtain the first flow value and the first flow deviation between the first flow value and the target flow value;

[0009] Step 4: If the first flow deviation is greater than the second target value, the opening compensation amount is determined by external disturbance factors, and the target opening is obtained based on the opening compensation amount and the first opening; if the first flow deviation is less than or equal to the second target value, the first opening is defined as the compensation opening; the optimized flow is determined based on the compensation opening.

[0010] Furthermore, the opening compensation amount is determined through external disturbance factors, including the following steps:

[0011] Step 41: Obtain the compensation factor group that affects the traffic flow, wherein the compensation factor group includes several compensation factors;

[0012] Step 42: Determine the corresponding standard value for each compensation factor; determine the degree of deviation based on each compensation factor and its corresponding standard value.

[0013] Step 43: Identify the influencing factor of the first flow deviation based on the degree of deviation, and compensate the opening degree based on the influencing factor to obtain the opening degree compensation amount.

[0014] Furthermore, the compensation factors include medium temperature deviation, inlet pressure fluctuation rate, viscosity change rate, and average friction force;

[0015] If the deviation of the medium temperature deviation is the largest, the medium temperature will be used as the influencing factor of the first flow deviation, and the first control compensation strategy will be executed based on the medium temperature deviation.

[0016] If the deviation of the inlet pressure fluctuation rate is the largest and the inlet pressure fluctuation rate is greater than 1.5, the inlet pressure fluctuation rate will be used as the first influencing factor of the flow deviation, and the second control compensation strategy will be implemented based on the inlet pressure fluctuation rate.

[0017] If the viscosity change rate is greater than 0.8 and the first flow rate is less than the third target value, viscosity will be used as the influencing factor of the first flow rate deviation, and the third control compensation strategy will be executed based on the viscosity change rate.

[0018] If none of the above conditions are met, friction force will be used as the influencing factor of the first flow deviation, and the fourth control compensation strategy will be executed based on the average friction force.

[0019] The first control compensation strategy, the second control compensation strategy, the third control compensation strategy, and the fourth control compensation strategy, that is, flow control is performed through the compensation opening degree to obtain the optimized flow rate.

[0020] Further, the first control compensation strategy includes:

[0021] Obtain the medium temperature deviation and query the pre-stored temperature-flow influence database to obtain the average flow rate offset rate corresponding to each 1°C temperature change at the first opening degree;

[0022] Determine the theoretical flow rate offset based on the medium temperature deviation and the average flow rate offset rate;

[0023] Determine the ratio of the first flow rate deviation to the theoretical flow rate offset; determine the compensation level coefficient according to the ratio: if the ratio < A, the compensation level coefficient is A1; if A ≤ ratio < B, the compensation level coefficient is B1; if ≥ B, the compensation level coefficient is B2; where, A1 < B1 < B2;

[0024] Determine the opening degree compensation amount based on the first flow rate value, the first flow rate deviation, and the first opening degree; determine the first compensation opening degree based on the opening degree compensation amount and the compensation level coefficient, and perform flow control based on the first compensation opening degree to obtain the first optimized flow rate.

[0025] Further, the second control strategy includes:

[0026] Obtain the inlet pressure volatility and preset the target range, determine the second compensation opening degree based on the pressure volatility, the boundary values of the target range, and / or the first flow rate deviation, and perform flow control based on the second compensation opening degree to obtain the second optimized flow rate.

[0027] Further, the third control strategy includes:

[0028] Obtain the viscosity change rate, look up the viscosity-opening degree correction coefficient according to the viscosity change rate and the first opening degree, determine the third compensation opening degree based on the viscosity-opening degree correction coefficient and the viscosity change rate, and perform flow control based on the third compensation opening degree to obtain the third optimized flow rate.

[0029] Further, the fourth control strategy includes:

[0030] Obtain the average friction force;

[0031] Compare the average friction force with the preset target friction force. If the target friction force > 1.3 times the average friction force, it is determined that there is static friction or jamming of the valve stem, and a reverse relaxation operation is performed;

[0032] After completing the reverse relaxation operation, re-collect the real-time flow rate value at the current moment, and determine the second flow rate deviation based on the real-time flow rate value and the target flow rate value at the current moment;

[0033] If the second flow deviation is less than the first target value, flow control will be performed based on the first opening; if the second flow deviation is greater than or equal to the first target value, the fourth compensation opening will be determined based on the second flow deviation, and flow control will be performed based on the fourth compensation opening to obtain the fourth optimized flow.

[0034] Further, a reverse relaxation operation is performed, including: reducing the first opening by 0.03 to obtain a reduced opening, holding it for 0.5 seconds, and then re-driving the reduced opening back to the first opening.

[0035] This application also discloses a flow control system for an equal percentage characteristic flow regulating valve, comprising the following modules:

[0036] Traffic data collection module: used to determine target traffic values ​​and real-time traffic values;

[0037] Deviation determination module: used to determine the flow deviation based on the target flow value and the real-time flow value;

[0038] Control module: used to preset a first target value, determine a first judgment condition based on the relationship between the flow deviation and the first target value, when the real-time flow value cannot meet the first judgment condition, determine the initial opening instruction by looking up a table and control the opening to obtain the first opening, control the flow based on the first opening to obtain the first flow value and the first flow deviation between the first flow value and the target flow value;

[0039] Compensation module: If the first flow deviation is greater than the second target value, the opening compensation amount is determined by external disturbance factors, and the target opening is obtained based on the opening compensation amount and the first opening; if the first flow deviation is less than or equal to the preset target threshold, the first opening is defined as the compensation opening; the optimized flow is determined based on the compensation opening.

[0040] Compared with existing technologies, the flow control method for an equal percentage characteristic flow regulating valve provided in this application achieves strong adaptability to complex dynamic environments under low flow or rapidly changing operating conditions by setting up a multi-disturbance identification mechanism based on four compensation factors and priority determination. This effectively overcomes the adaptability limitations of traditional control methods due to their reliance on fixed parameters. The system synchronously monitors and analyzes the deviation of medium temperature deviation, inlet pressure fluctuation rate, viscosity change rate, and average friction force. Combined with the valve's equal percentage characteristics and operating condition sensitivity, a priority determination logic is established. This allows for accurate identification of the dominant disturbance source and priority execution of corresponding compensation strategies when multiple disturbances coexist, avoiding response inaccuracies caused by disturbance coupling or judgment lag in traditional methods. Furthermore, by setting up a residual error fine correction stage, the system further evaluates the continued impact of each factor after compensating for the main disturbance. For secondary disturbances that are not completely eliminated, orderly and sequential auxiliary compensation is implemented to ensure the accuracy and stability of the control action. This solution enables comprehensive identification and hierarchical response to various disturbance factors, which not only improves the dynamic response capability and steady-state accuracy of the control system, but also enables the flow control valve to maintain high robustness and adaptability under extreme conditions through a mechanism-based and structured compensation process design. This fundamentally solves the technical bottlenecks of the existing technology, such as one-sided disturbance identification, simple compensation logic, and poor adaptability to operating conditions. Attached Figure Description

[0041] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0042] Figure 1 A schematic flowchart illustrating a flow control method for an equal percentage characteristic flow regulating valve provided in an embodiment of this application;

[0043] Figure 2 A structural diagram of a flow control system for an equal percentage characteristic flow regulating valve provided in an embodiment of this application;

[0044] Figure 3 This is a block diagram of an electronic device provided in an embodiment of this application. Detailed Implementation

[0045] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0046] The following describes a flow control method for an equal percentage characteristic flow regulating valve according to an embodiment of this application, with reference to the accompanying drawings.

[0047] It should be noted that the execution subject of the flow control method of the equal percentage characteristic flow regulating valve in the present application embodiment is the flow control system of the equal percentage characteristic flow regulating valve in the present application embodiment. The flow control system of the equal percentage characteristic flow regulating valve can be configured in an electronic device so that the electronic device can perform the flow control function of the equal percentage characteristic flow regulating valve.

[0048] like Figure 1 As shown, the flow control method for an equal percentage characteristic flow regulating valve includes the following steps:

[0049] Step 1: Determine the target traffic value and the real-time traffic value.

[0050] The target flow rate is set based on system operating requirements. In this embodiment, the target flow rate is dynamically set by the upper-level control system according to actual process requirements. For example, in a chemical reaction feeding process, the operator or automation system sets the target flow rate to 120 m³ / h. The real-time flow rate is measured online by an electromagnetic flow meter installed on the pipeline. The sensor continuously collects the medium flow velocity at a sampling period of 100 ms and converts it into a real-time flow rate value Qact by combining it with the pipeline cross-sectional area. The measurement data is filtered and then sent to the control unit.

[0051] Step 2: Determine the flow deviation based on the target flow value and the real-time flow value.

[0052] Flow deviation is calculated to assess the current control status and provide a basis for subsequent adjustments. Flow deviation ΔQ is defined as the difference between the target flow value Qset and the real-time flow value Qact obtained from real-time measurement, and its calculation formula is as follows:

[0053] ΔQ = Qset - Qact.

[0054] Step 3: Preset a first target value, determine a first judgment condition based on the first target value, and when the real-time flow value cannot meet the first judgment condition, determine the initial opening instruction by looking up the table and control the opening to obtain the first opening. Adjust the flow based on the first opening to obtain the first flow value and the first flow deviation between the first flow value and the target flow value.

[0055] A preset first target value y1 is established, where y1 = 0.05Qmax (i.e., the allowable error is 5% of the rated maximum flow rate Qmax). ΔQ ≤ y1 is used as the first judgment condition. When the real-time flow rate meets this condition, the current valve opening is considered to meet the basic control accuracy requirements, and the system maintains the existing opening without further adjustment. This judgment mechanism avoids unnecessary actions when the error is small, improving system stability. When the real-time flow rate fails to meet the first judgment condition, the current state is determined to have not reached the control target, and an initialization adjustment process needs to be initiated. In this case, the system no longer relies on the slow PID integral process but directly obtains an initial opening command close to the target flow rate value by looking up a pre-calibrated flow-opening characteristic table, achieving rapid approximation.

[0056] This flow-opening characteristic table is based on the valve's equal percentage flow characteristic function: A theoretical mapping table is constructed. Here, 'a' is a constant percentage (preferably a=50 in this embodiment), and 'd' is the normalized opening degree (range 0-1; the normalized opening degree represents the proportion of the valve core's current position relative to the stroke from fully closed (0%) to fully open (100%); any opening degree described below is a normalized opening degree). The specific construction method is as follows: During the calibration stage before the valve leaves the factory, through experimental testing or fluid simulation, actual flow data corresponding to multiple opening points (such as 10%, 20%, ..., 100%) are obtained, and the relationship between the fitted flow rate and the normalized opening degree is obtained: And solve it in reverse to get the opening calculation formula: Where Q is the fitted flow rate.

[0057] After the valve completes its operation and the flow stabilizes (usually taking 2-5 seconds), the system re-acquires the actual flow rate, records it as the first flow rate value Q1, and calculates the first flow rate deviation ΔQ1 between it and the target value: ΔQ1=Qset−Q1.

[0058] Step 4: If the first flow deviation is greater than the second target value, the opening compensation amount is determined by external disturbance factors, and the target opening is obtained based on the opening compensation amount and the first opening; if the first flow deviation is less than or equal to the second target value, the first opening is defined as the compensation opening; the optimized flow is determined based on the compensation opening.

[0059] At this point, this embodiment introduces a more stringent second target value y2: y2 = 0.03Qmax, used to determine whether subsequent disturbance identification and compensation mechanisms need to be initiated. The first target value serves as a rapid assessment threshold for the system's current state, primarily used to determine whether significant adjustments are necessary. It allows for a certain range of error, avoiding frequent initiation of adjustment processes when approaching the target, thereby improving system response efficiency and reducing actuator wear. The second target value in the second stage is a threshold for refined evaluation of residual errors after a theoretical initial adjustment. Its stricter setting (3%) means that only when a non-negligible deviation remains after the initial adjustment is it determined that external disturbances (such as temperature changes, pressure fluctuations, etc.) have an impact, thus triggering subsequent compensation mechanisms.

[0060] Step 41: Obtain the compensation factor group that affects the flow rate. The compensation factor group includes several compensation factors. The compensation factors include medium temperature deviation, inlet pressure fluctuation rate, viscosity change rate, and average friction force.

[0061] These compensation factors are all key external or internal disturbances affecting the actual flow control accuracy of regulating valves. Medium temperature deviation indirectly affects flow rate by altering the fluid's physical properties. Increased temperature typically leads to decreased liquid viscosity and reduced gas density, thus increasing flow rate at the same opening degree, and vice versa. Especially for high-viscosity media (such as heavy oil and polymer solutions), even small temperature changes can significantly alter flow resistance, causing flow rate deviations from the set value. Inlet pressure fluctuation rate directly affects the pressure difference across the valve. Since flow rate is proportional to the square root of the pressure difference, large upstream pressure fluctuations will cause flow rate fluctuations even with a constant valve opening, severely disrupting the stability of the flow-opening relationship. Viscosity change rate directly determines the resistance characteristics of fluid flow in pipes and valves. Increased viscosity leads to increased pressure drop across the valve, resulting in actual flow rate lower than theoretical value, especially sensitive under low opening or low flow conditions. This change may be caused by changes in medium composition, temperature drift, or chemical reactions. The average friction force reflects the dynamic friction state between the valve stem and the packing. After long-term operation, the friction force increases due to wear, oxidation or lubrication failure, which will cause the actuator to respond slowly, be inaccurate in positioning, and exhibit crawling or jamming phenomena, causing the actual opening degree to deviate from the command value, and thus causing flow control deviation.

[0062] The current medium temperature is collected in real time by a high-precision temperature sensor installed near the valve inlet, and the difference between this temperature and the standard reference temperature under the same operating condition is used to obtain the medium temperature deviation. Further analysis of the physical properties database of the medium type (e.g., water, oil, steam) is conducted to assess its impact on viscosity and density. A pressure sequence is continuously measured by an inlet pressure sensor. The ratio of the standard deviation to the average pressure within a set time window (e.g., 10 seconds) yields the inlet pressure fluctuation rate, used to quantify the degree of pressure instability. The viscosity change rate can be obtained in two ways: first, by directly measuring the current viscosity using an online viscometer and calculating the viscosity change rate using historical benchmark values; second, when direct measurement is not possible, by indirectly estimating the viscosity change trend based on a temperature-viscosity empirical model (e.g., the Andrade equation) from temperature changes. The average friction force is indirectly estimated by analyzing the drive current or thrust signal of the actuator: during valve operation, the control system records the drive current I required to maintain a certain opening degree. After deducting the basic current required to overcome the fluid pressure difference, the remaining portion corresponds to mechanical friction force. The system filters and averages the friction force samples over a period of time to obtain the average friction force, used to assess whether the valve stem movement is abnormal. All of the above factors are used in a standardized form in the subsequent deviation calculation, providing a reliable basis for disturbance identification and compensation.

[0063] Step 42: Determine the corresponding standard value based on each compensation factor; determine the degree of deviation based on each compensation factor and its corresponding standard value.

[0064] In the flow control method of this invention, the standard value involved in step 42 refers to the fluctuation benchmark of each compensation factor under normal operating conditions, i.e., the standard deviation threshold. This standard deviation threshold is essentially a typical fluctuation level set by the system for each compensation factor, used to measure whether the current measurement value deviates from the normal range.

[0065] For medium temperature deviation, the standard deviation threshold represents the natural fluctuation level of the temperature signal during stable system operation. This value is calculated by continuously acquiring inlet temperature sensor data under typical operating conditions (sampling period of 1 second, lasting 1 hour), calculating the standard deviation of the temperature series, and taking its 95th percentile as the benchmark. For example, in a certain chemical process, if the measured temperature fluctuation standard deviation is concentrated between 0.3-0.6℃, then 0.6℃ is taken, indicating that when the temperature change exceeds this fluctuation range, it is considered to have a significant thermal disturbance.

[0066] For inlet pressure volatility, the standard deviation threshold reflects the inherent volatility of upstream pressure under conditions of no external disturbance. Specifically, it is determined as follows: under stable valve opening and essentially constant flow, inlet pressure signals are collected, and the ratio of the standard deviation to the average pressure within each 10-second window is calculated (i.e., volatility). Then, the volatility sequences from multiple steady-state periods are statistically analyzed, and their standard deviation is used as the standard deviation threshold. For example, if historical data shows a standard deviation of 0.015 for pressure volatility, then setting it to 0.015 means that when the actual volatility is significantly higher than this value, the system will determine that a pressure source disturbance exists.

[0067] For viscosity change rate, the standard deviation threshold is set based on the medium type and operational experience. If the system is equipped with an online viscometer, the standard deviation is calculated and the upper limit is taken by long-term monitoring of the fluctuation of the relative viscosity change rate; if there is no direct measurement, the viscosity change trend is estimated based on the temperature-viscosity model, and the typical fluctuation level is determined by combining historical data. For example, for water-based media, the standard deviation threshold can be set to 0.02 (i.e., 2%), while for high-viscosity oils, it can be relaxed to 0.05.

[0068] For the mean friction force, its standard deviation threshold reflects the stability of the friction force during valve stem movement. This value is calculated by performing multiple opening and closing operations after valve installation or maintenance, recording the drive current or thrust signal, and then retrieving the friction force sequence to calculate its standard deviation. For example, if the measured standard deviation of friction force fluctuation is 8 N, then the standard deviation threshold is set to 10 N (with a margin), which serves as a benchmark for judging friction anomalies in subsequent operation.

[0069] After determining the standard deviation threshold for each compensation factor, calculate its degree of deviation:

[0070] r i x represents the degree of deviation of the i-th compensation factor. i The value of the i-th compensation factor (medium temperature deviation, inlet pressure fluctuation rate, viscosity change rate, and average friction force). Let be the standard value of the i-th compensation factor.

[0071] Step 43: Identify the influencing factor of the first flow deviation based on the degree of deviation, and compensate the opening degree based on the influencing factor to obtain the opening degree compensation amount.

[0072] In this embodiment, the compensation factor with the largest deviation is taken as the influencing factor of the first flow deviation.

[0073] In this embodiment, based on the medium temperature deviation, inlet pressure fluctuation rate, viscosity change rate, and average friction force, and combined with the deviation degree of each compensation factor and the valve operating characteristics, the compensation priority of the influencing factors is determined. Specifically, the following judgment rules are included: If the inlet pressure fluctuation rate is greater than 15%, the inlet pressure fluctuation is immediately taken as the influencing factor of the first flow deviation, and the second control compensation strategy is activated, regardless of whether the deviation degree of other compensation factors is greater; if the first opening degree is less than 0.3, and the deviation degree of the average friction force exceeds twice the standard value of the average friction force, the friction force is taken as the influencing factor of the first flow deviation, and the fourth control compensation strategy is executed first; if the deviation degree of the medium temperature deviation or viscosity change rate continuously exceeds its standard deviation threshold for more than 30 seconds, its priority is increased by one level, and it is compensated first over other factors that have not continuously exceeded the limit; if none of the above conditions are met, the compensation factor with the largest deviation degree is taken as the influencing factor of the first flow deviation, and the corresponding control compensation strategy is executed.

[0074] In a specific embodiment of the present invention, to improve the accuracy of disturbance identification and the engineering adaptability of the control strategy, this embodiment introduces a special priority design mechanism based on valve characteristics and operating condition sensitivity to optimize the judgment criteria of influencing factors. This mechanism is not limited to simply comparing the deviation of each compensation factor, but comprehensively considers the physical characteristics of the regulating valve, the importance of key process variables, and the temporal evolution trend of the disturbance to achieve a more scientific priority ranking. Specifically, this embodiment pre-sets multi-level judgment rules: First, since the inlet pressure is the core power source driving the flow, its drastic fluctuations will directly destroy the stability of the entire regulating system. Therefore, a veto mechanism for key disturbances is set: as long as the inlet pressure fluctuation rate exceeds 15%, regardless of whether the deviation of temperature, viscosity, or friction is greater, it is immediately judged as the first influencing factor of flow deviation, and the second control compensation strategy is activated to ensure that the system prioritizes pressure stabilization when the pressure source is abnormal. Second, addressing the control challenges under low opening conditions, this embodiment utilizes the valve's equal percentage characteristics for priority adjustment. When the first opening is less than 0.3, the valve core is in a small flow area region with relatively low fluid dynamics; at this time, the influence of mechanical friction on the valve positioning accuracy is significantly amplified. Therefore, if the deviation of the mean friction force reaches a moderate or higher level (i.e., exceeds twice its standard deviation threshold), even if the deviation is not the maximum, its priority is raised to the highest level, and the reverse relaxation operation in the fourth control compensation strategy is executed first to effectively eliminate static friction or jamming. Secondly, for disturbances such as medium temperature deviation and viscosity change rate, which have large inertia and slow change characteristics, a time accumulation effect judgment is introduced. If a factor, although not deviating to its maximum at the current moment, has continuously exceeded the standard deviation threshold for more than 30 seconds, it is considered to have a persistent disturbance, and its priority is raised one level to prevent slowly changing disturbances from gradually deteriorating control performance. Finally, if none of the above special conditions are met, this embodiment degenerates into general logic: the compensation factor with the largest deviation is taken as the influencing factor, and the corresponding compensation strategy is executed.

[0075] If the deviation of the medium temperature is the largest, the medium temperature is used as the influencing factor of the first flow deviation, and the first control compensation strategy is executed based on the medium temperature deviation.

[0076] The first control compensation strategy includes:

[0077] Obtain the medium temperature deviation ΔT and query the pre-stored temperature and flow rate influence database to obtain the average flow rate offset rate pT corresponding to each 1℃ temperature change under the first opening degree.

[0078] The temperature-flow rate impact database was established through factory calibration experiments: temperature disturbances of ±10°C were applied at different opening degrees, the steady-state flow rate change rate was recorded, and the average was taken. For example, when the current first opening degree is 0.42, it was found that every 1°C increase in temperature leads to an increase in flow rate of approximately 0.9% / °C.

[0079] Determine the theoretical flow offset Δq based on the medium temperature deviation and the average flow rate offset rate: Δq = pT × ΔT.

[0080] Determine the ratio of the first flow deviation to the theoretical flow offset; determine the compensation level coefficient k based on the ratio: k = |ΔQ1| / |Δq|; if the ratio < A, the compensation level coefficient is A1; if A ≤ ratio < B, the compensation level coefficient is B1; if ≥ B, the compensation level coefficient is B2; where, A1 < B1 < B2;

[0081] Determine the compensation intensity level based on the k value: if k < 0.8, set the base compensation coefficient Kbase, Kbase = 0.9; if 0.8 ≤ k ≤ 1.2, then Kbase = 1.0; if k > 1.2, then Kbase = 1.1;

[0082] Determine the opening compensation amount Bbase based on the first flow value, the first flow deviation, and the first opening dcurr: Bbase = log((Q1 + ΔQ1) / Qmax) - dcurr. Determine the first compensated opening Bcomp1 based on the opening compensation amount and the compensation level coefficient: Bcomp1 = Kbase × Bbase, and perform flow control based on the first compensated opening to obtain the first optimized flow rate.

[0083] The calculation of the opening compensation amount stems from the characteristics of the equal percentage regulating valve itself: when the opening changes, the flow does not increase uniformly but changes according to an exponential law. That is, the larger the opening, the greater the flow change caused by the same opening change. If we want to reach the target flow from the current flow, the total opening required can be estimated by taking the logarithm of the ratio of the target flow to the maximum flow. The target flow is the current flow plus the deviation that needs to be compensated. After calculating this theoretically total opening, subtract the actual current opening of the valve, and the remaining difference is the amount of opening that still needs to be increased or decreased, which is the so-called opening compensation amount. It directly utilizes the adjustment characteristics of the valve itself, making the calculation of the compensation amount more in line with the actual physical law, especially when the flow changes greatly or the opening is small, it is more accurate than simple linear estimation.

[0084] If the deviation degree of the inlet pressure volatility is the largest and the inlet pressure volatility is greater than 1.5, take the inlet pressure fluctuation as the influencing factor of the first flow deviation, and execute the second control compensation strategy based on the inlet pressure volatility.

[0085] The second control strategy includes:

[0086] Obtain the inlet pressure volatility and preset the target range [0.06, 0.12]. Determine the second compensation opening based on the pressure volatility YP, the boundary values of the target range, and / or the first flow deviation. Perform flow control based on the second compensation opening to obtain the second optimized flow rate. If YP > 0.12, enable the feedforward compensation mode, and the second compensation opening Bcomp2: Bcomp2 = c1×(YP - 0.12), where c1 is the pressure response coefficient with a value of 0.05. If 0.06 < YP ≤ 0.12, enable the feedback fine-tuning mode, Bcomp2 = c2×ΔQ1, where c2 is the proportional gain with a value of 0.003. If YP ≤ 0.06, determine that the pressure impact is negligible, and Bcomp2 = 0.

[0087] If the viscosity change rate is greater than 0.8 and the first flow value is less than the third target value, use the viscosity as the influencing factor of the first flow deviation, and execute the third control compensation strategy based on the viscosity change rate.

[0088] The third target value is used to trigger viscosity compensation, and its conditions are: viscosity change rate > 0.8 and first flow value < third target value, that is, when the flow rate itself is low, the viscosity change has a more sensitive impact on the control accuracy; in low-flow conditions (such as less than 8%Qmax), the valve opening is small, the flow channel is narrow, and the impact of the medium viscosity change on the flow resistance is amplified, which is likely to cause control instability. Setting the third target value to 0.08Qmax can effectively cover the small-flow, high-viscosity sensitive area, ensure timely activation of viscosity compensation under critical conditions, and improve control robustness.

[0089] The third control strategy includes:

[0090] Obtain the viscosity change rate, look up the viscosity-opening correction coefficient according to the viscosity change rate and the first opening, determine the third compensation opening based on the viscosity-opening correction coefficient and the viscosity change rate, and perform flow control based on the third compensation opening to obtain the third optimized flow rate.

[0091] According to the viscosity change rate ζ and the first opening dcurr, look up the viscosity-opening correction coefficient Kv. When dcurr < 0.3, Kv = 0.06 + 0.02×ζ; when dcurr ≥ 0.3, Kv = 0.04 + 0.01×ζ. Calculate the third compensation opening Bcomp3: Bcomp3 = Kv×ζ.

[0092] If none of the above conditions are met, use the friction force as the influencing factor of the first flow deviation, and execute the fourth control compensation strategy based on the average friction force.

[0093] The fourth control strategy includes:

[0094] Obtain the average friction force. Compare the average friction force with the preset target friction force. If the target friction force is greater than 1.3 times the average friction force, it is determined that the valve stem has static friction or is stuck, and a reverse relaxation operation is performed: the first opening degree is reduced by 0.03 to obtain the reduced opening degree, which is held for 0.5 seconds, and then the reduced opening degree is driven back to the first opening degree.

[0095] After the valve is assembled, multiple full-stroke switching tests are performed under standard operating conditions (normal temperature, clean medium, rated load). The current or thrust signal of the drive motor is collected, and the average frictional force during the valve stem movement is deduced. The statistical average value is then taken as the initial target frictional force. This part is a conventional technical method and will not be described in detail in this embodiment.

[0096] After completing the reverse relaxation operation, the real-time flow value at the current moment is collected again, and the second flow deviation is determined based on the real-time flow value at the current moment and the target flow value.

[0097] If the second flow deviation is less than the first target value, flow control will be performed based on the first opening; if the second flow deviation is greater than or equal to the first target value, the fourth compensation opening will be determined based on the second flow deviation, and flow control will be performed based on the fourth compensation opening to obtain the fourth optimized flow.

[0098] The fourth compensation opening Bcomp4: Bcomp4 = dcurr + Ks × ΔQ2, where Ks is the sensitivity coefficient and ΔQ2 is the second flow deviation.

[0099] After completing the main disturbance compensation (such as the second control compensation strategy initiated due to inlet pressure fluctuation rate > 15%), the control process does not immediately end, but instead enters the residual error fine correction stage. This stage aims to eliminate minor deviations caused by model errors, slow-varying disturbances, or actuator nonlinearity, thereby achieving high-precision flow control.

[0100] In one specific embodiment of the present invention, the residual error is further finely corrected to improve the final control accuracy; the residual error fine correction process includes:

[0101] After executing the main disturbance compensation strategy, the current real-time flow value is re-acquired and combined with the target flow value to calculate the first residual flow deviation. If the first residual flow deviation is greater than the preset fine-tuning threshold, the residual error correction process is initiated. The fine-tuning threshold is 2%-5% of the maximum rated flow, preferably 3%. The deviation of the medium temperature deviation, viscosity change rate, and average friction force is re-evaluated, and combined with the standard value of the compensation factor, it is determined whether an auxiliary compensation strategy needs to be initiated. If the deviation of the re-evaluated average friction force exceeds 1.5 times the standard value of the average friction force, and the current opening is less than 0.3, a reverse relaxation operation is performed to eliminate the static friction effect. If the deviation of the temperature or viscosity continues to exceed the standard value of the temperature or viscosity for more than 20 seconds, the opening correction coefficient is obtained by looking up the table according to its change rate, and a small opening adjustment is applied.

[0102] The auxiliary compensation strategy is executed serially after the main disturbance compensation is completed, and only one highest priority influencing factor is activated as an auxiliary factor each time. The corresponding control strategy is executed based on the auxiliary factor to achieve auxiliary compensation, avoiding oscillation caused by multi-strategy coupling. After the auxiliary compensation is completed, the flow rate is detected again. If the accuracy requirements are still not met, a final fine-tuning is performed based on low-gain PID to ensure that the flow rate is stable within the target range.

[0103] This embodiment uses the "second control compensation strategy activated when the inlet pressure fluctuation rate > 15%" as an example. After the second control compensation strategy is completed and the valve action stabilizes, the actual flow rate is re-acquired, and the first residual flow deviation is calculated. If the first residual flow deviation is greater than the preset fine-tuning threshold, it indicates that there is still a non-negligible residual error, which requires further processing. At this time, this embodiment re-evaluates the current state of each compensation factor: if the re-evaluated average friction force is detected to be 1.4 times the standard value, and the current opening is 0.25, it indicates that the valve stem may have slight jamming, affecting the positioning accuracy. Although its deviation does not reach the level of the main disturbance, it is enough to cause a small deviation. This embodiment then executes the reverse relaxation operation in the fourth control strategy: the current opening is pulled back by 0.03 to 0.22, held for 0.5 seconds to release static friction, and then slowly restored to the original opening, thereby improving the response consistency of the actuator. If the medium temperature continues to be 6°C higher for more than 40 seconds, and the viscosity change rate is stable at -5%, it is determined that there is a continuous physical property disturbance. At this point, the controller retrieves the temperature-opening correction mapping table, obtains the compensation coefficient (e.g., +0.015) for the corresponding opening, and fine-tunes the current opening to achieve precise compensation. All auxiliary compensations are executed serially and step-by-step to avoid overshoot caused by the superposition of multiple compensation signals. After each auxiliary operation, the flow rate is resampled to determine if it meets the standard. If residual deviation still exists after the above auxiliary compensation (e.g., due to sensor noise), low-gain PID fine-tuning is finally initiated, using a very small integral action for final convergence to ensure that the flow rate is stable within ±1%. The three-level control architecture of primary disturbance priority - auxiliary correction - PID fine-tuning not only ensures rapid response to sudden disturbances but also achieves high-precision elimination of residual errors, which is significantly better than traditional single compensation or control methods that rely entirely on PID. This fully demonstrates the technical advantages of this invention in balancing dynamic performance and steady-state accuracy under complex operating conditions.

[0104] The first, second, third, and fourth control compensation strategies are to control the flow by compensating for the opening degree, thereby obtaining optimized flow.

[0105] This embodiment, based on the first, second, third, or fourth compensation opening degree or the opening degree corrected for residual error, implements the main disturbance compensation strategy. The controller converts the compensation opening degree signal into a standard analog quantity (e.g., 4–20mA) or a digital pulse signal to control the motor or cylinder of the actuator, ensuring the valve opening accurately reaches the calculated value. After the action is completed, the system waits for a short stabilization period (usually 1–3 seconds) to eliminate the effects of mechanical inertia and transient fluid response. Subsequently, the real-time flow value in the pipeline is collected in real time by a flow sensor. This value is the optimized flow rate after compensation. This optimized flow rate is then compared with the target flow rate to determine if it meets the control accuracy requirements. If it does, the current opening degree is maintained; otherwise, the disturbance identification process is restarted, and the next round of compensation iteration begins. Through calculating the compensation opening degree, driving the valve, collecting feedback, and evaluating, each control strategy not only achieves targeted suppression of specific disturbances but also verifies the compensation effectiveness through actual flow, ensuring that the final optimized flow rate gradually approaches the set target, significantly improving the dynamic response capability and steady-state control accuracy of the control system.

[0106] To verify the effectiveness of the first to fourth control compensation strategies, a typical industrial control valve system operating scenario is designed. An electrically operated control valve is used to control the cooling water flow rate, with a maximum flow rate of 100 m³ / h. 3 / h, target setting value is 80m 3 / h. Under initial conditions, the control accuracy was severely reduced due to the superposition of multiple disturbances, including increased temperature, fluctuating inlet pressure, changes in medium viscosity, and increased valve stem friction. Based on real-time monitoring data, various compensation strategies were triggered sequentially to achieve optimization, and the execution results are shown in Tables 1 and 2.

[0107] Experimental conditions: Valve type is equal percentage characteristic control valve. Control objectives include: initial opening of 0.65 (basic opening), 70m 3 Actual initial flow rate / h. Disturbance factors: Temperature rise: +8°C, leading to a decrease in fluid density and reduced flow resistance. Inlet pressure fluctuation rate: 0.14; viscosity change rate: 0.9; average friction force is 1.4 times higher than the target friction force.

[0108] Table 1. Results of the compensation strategy where inlet pressure fluctuation is the primary disturbance and viscosity change is the secondary disturbance.

[0109]

[0110] Table 2. Results of the compensation strategy where medium temperature deviation is the primary disturbance and friction is the secondary disturbance.

[0111]

[0112] As shown in Table 1, when inlet pressure fluctuation is the primary disturbance and viscosity change is the secondary disturbance, the second control strategy is first implemented based on the pressure disturbance characteristics, increasing the initial flow rate from 70 m³ / h to 76.5 m³ / h, and reducing the residual deviation from 12.5% ​​to 4.4%, effectively suppressing the flow lag problem caused by sudden pressure changes. Subsequently, a third control strategy is introduced for viscosity compensation, further optimizing the flow rate to 79.5 m³ / h, and reducing the residual deviation to 0.6%, fully demonstrating the compensation logic of stabilization followed by precision in pressure-dominated scenarios. In the case shown in Table 2, where temperature deviation is the primary disturbance and frictional anomaly is the secondary disturbance, the system prioritizes the first control strategy for temperature compensation, increasing the flow rate from 65 m³ / h to 73.5 m³ / h, and significantly reducing the deviation from 18.8% to 8.1%, solving the problem of nonlinear flow resistance changes caused by thermal effects. Then, a fourth control strategy is used to perform reverse relaxation and repositioning operations on mechanical friction, ultimately achieving a high-precision stable output with a flow rate of 79.9 m³ / h and a deviation of only 0.1%. The two sets of experiments described above demonstrate that this application establishes an intelligent decision-making mechanism based on the type, intensity, and influence path of disturbances, achieving differentiated responses and orderly compensation for primary and secondary disturbances. This avoids coupling interference and over-adjustment phenomena that may occur in traditional multivariable control. This method possesses good adaptability and scalability, enabling flexible matching of the optimal compensation sequence according to different process conditions. It overcomes the technical bottleneck of single closed-loop control's inability to cope with the superposition of multiple disturbances, exhibiting significantly superior comprehensive control capabilities and engineering practicality compared to existing technologies.

[0113] like Figure 2 As shown, this embodiment also discloses a flow control system for an equal percentage characteristic flow regulating valve, including the following modules:

[0114] Traffic data collection module: used to determine target traffic values ​​and real-time traffic values;

[0115] Deviation determination module: used to determine the flow deviation based on the target flow value and the real-time flow value;

[0116] Control module: used to preset a first target value, determine a first judgment condition based on the relationship between the flow deviation and the first target value, when the real-time flow value cannot meet the first judgment condition, determine the initial opening instruction by looking up a table and control the opening to obtain the first opening, control the flow based on the first opening to obtain the first flow value and the first flow deviation between the first flow value and the target flow value;

[0117] Compensation module: If the first flow deviation is greater than the second target value, the opening compensation amount is determined by external disturbance factors, and the target opening is obtained based on the opening compensation amount and the first opening; if the first flow deviation is less than or equal to the preset target threshold, the first opening is defined as the compensation opening; the optimized flow is determined based on the compensation opening.

[0118] To implement the above embodiments, this application also proposes an electronic device. Please see [link to relevant documentation]. Figure 3 , Figure 3 This is a schematic diagram of the structure of the electronic device provided in an embodiment of this application. For example... Figure 3 As shown, the electronic device 500 includes: a processor 501 and a memory 502 communicatively connected to the processor 501; the memory 502 stores computer-executable instructions; the processor 501 executes the computer-executable instructions stored in the memory to implement the method provided in the foregoing embodiments.

[0119] To implement the above embodiments, this application also proposes a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the methods provided in the foregoing embodiments.

[0120] To implement the above embodiments, this application also proposes a computer program product, including a computer program that, when executed by a processor, implements the methods provided in the foregoing embodiments.

[0121] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this application.

Claims

1. A flow control method for an equal-percentage characteristic flow regulating valve, characterized by, The method comprises the following steps: Step 1, determining a target flow value and a real-time flow value; Step 2, determining a flow deviation according to the target flow value and the real-time flow value; Step 3, presetting a first target value, determining a first judgment condition according to the first target value, when the real-time flow value cannot meet the first judgment condition, determining an initial opening degree command through a lookup table and controlling the opening degree to obtain a first opening degree, and based on the first opening degree, regulating and controlling the flow to obtain a first flow value and a first flow deviation between the first flow value and the target flow value; Step 4, if the first flow deviation is greater than a second target value, determining an opening degree compensation amount through external disturbance factors, and obtaining a target opening degree based on the opening degree compensation amount and the first opening degree; If the first flow deviation is less than or equal to the second target value, defining the first opening degree as a compensation opening degree; Based on the compensation opening degree, determining an optimized flow; Determining an opening degree compensation amount through external disturbance factors comprises the following steps: Step 41, obtaining a compensation factor group affecting the flow, the compensation factor group comprising a plurality of compensation factors; the compensation factors comprising a medium temperature deviation, an inlet pressure fluctuation rate, a viscosity change rate and a friction force average value; Step 42, determining a corresponding standard value based on each compensation factor; determining a deviation degree according to each compensation factor and the corresponding standard value; Step 43, identifying an influence factor of the first flow deviation according to the deviation degree, and compensating the opening degree based on the influence factor to obtain the opening degree compensation amount; If the deviation degree of the medium temperature deviation is the largest, taking the medium temperature as the influence factor of the first flow deviation, and executing a first control compensation strategy based on the medium temperature deviation; If the deviation degree of the inlet pressure fluctuation rate is the largest and the inlet pressure fluctuation rate is greater than 1.5, taking the inlet pressure fluctuation as the influence factor of the first flow deviation, and executing a second control compensation strategy based on the inlet pressure fluctuation rate; If the viscosity change rate is greater than 0.8 and the first flow value is less than a third target value, taking the viscosity as the influence factor of the first flow deviation, and executing a third control compensation strategy based on the viscosity change rate; If none of the above conditions is met, taking the friction force as the influence factor of the first flow deviation, and executing a fourth control compensation strategy based on the friction force average value; The first control compensation strategy, the second control compensation strategy, the third control compensation strategy and the fourth control compensation strategy are used to control the flow through the compensation opening degree to obtain the optimized flow.

2. The flow control method of a percentage characteristic flow regulating valve according to claim 1, wherein The first control compensation strategy comprises: Obtaining the medium temperature deviation and querying a pre-stored temperature flow influence database to obtain an average flow deviation rate corresponding to each 1℃ temperature change under the first opening degree; Determining a theoretical flow deviation amount according to the medium temperature deviation and the average flow deviation rate; Determining a proportion of the first flow deviation and the theoretical flow deviation amount; Determining a compensation level coefficient according to the proportion: if the proportion is less than A, the compensation level coefficient is A1; If A is less than or equal to the proportion and less than B, the compensation level coefficient is B1; If the proportion is greater than or equal to B, the compensation level coefficient is B2; wherein A1 Determine an opening degree compensation amount based on the first flow value, the first flow deviation, and the first opening degree; determine a first compensation opening degree based on the opening degree compensation amount and a compensation level coefficient, and perform flow control based on the first compensation opening degree to obtain a first optimized flow.

3. The flow control method of a percentage characteristic flow regulating valve according to claim 1, wherein The second control strategy comprises: Obtain an inlet pressure fluctuation rate and preset a target interval, determine a second compensation opening degree based on the pressure fluctuation rate, a boundary value of the target interval, and / or the first flow deviation, and perform flow control based on the second compensation opening degree to obtain a second optimized flow.

4. The flow control method of a percentage characteristic flow regulating valve according to claim 1, wherein The third control strategy comprises: Obtain a viscosity change rate, obtain a viscosity opening degree correction coefficient according to the viscosity change rate and the first opening degree, determine a third compensation opening degree based on the viscosity opening degree correction coefficient and the viscosity change rate, and perform flow control based on the third compensation opening degree to obtain a third optimized flow.

5. The flow control method of a percentage characteristic flow regulating valve according to claim 1, wherein, The fourth control strategy comprises: Obtain a mean value of friction force; Compare the mean value of friction force with a preset target friction force, if the target friction force is greater than 1.3 times the mean value of friction force, determine that there is static friction or sticking of the valve stem, and perform a reverse relaxation operation; After the reverse relaxation operation is completed, re-collect a real-time flow value at the current time, and determine a second flow deviation based on the real-time flow value at the current time and the target flow value; If the second flow deviation is less than a first target value, perform flow control based on the first opening degree; if the second flow deviation is greater than or equal to the first target value, determine a fourth compensation opening degree according to the second flow deviation, and perform flow control based on the fourth compensation opening degree to obtain a fourth optimized flow.

6. The flow control method of a percentage characteristic flow regulating valve according to claim 5, wherein The reverse relaxation operation comprises: reducing the first opening degree by 0.03 to obtain a reduced opening degree, maintaining the reduced opening degree for 0.5 seconds, and driving the reduced opening degree back to the first opening degree.

7. A flow control system of an equal-percentage characteristic flow regulating valve for executing the flow control method of any one of the above claims 1 to 6, characterized by, The method comprises the following modules: A flow data collection module for determining a target flow value and a real-time flow value; A deviation determination module for determining a flow deviation according to the target flow value and the real-time flow value; A regulation and control module for presetting a first target value, determining a first judgment condition according to a size relationship between the flow deviation and the first target value, determining an initial opening degree command by looking up a table when the real-time flow value cannot meet the first judgment condition, and controlling the opening degree to obtain a first opening degree, regulating and controlling flow based on the first opening degree to obtain a first flow value and a first flow deviation between the first flow value and the target flow value; A compensation module for determining an opening degree compensation amount through external disturbance factors if the first flow deviation is greater than a second target value, and obtaining a target opening degree based on the opening degree compensation amount and the first opening degree; If the first flow deviation is less than or equal to a preset target threshold, the first opening degree is defined as a compensation opening degree; Determine an optimized flow based on the compensation opening degree.

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