Control method and system for intelligent matching of fan frequency and roller way speed of high-speed wire air cooling roller way

Abstract

The invention discloses a control method and system for intelligent matching of the fan frequency and the roller way speed of a high-speed wire air cooling roller way, and relates to the technical field of rolled steel cooling. The method comprises the following steps: designing eight subsystems: a finished product coil head and middle-rear section fan frequency optimization system, a roller way crawling frequency optimization system, an air cooling roller way global acceleration and gradient connection speed system, a fan-roller way speed interval matching correction system, an interval temperature drop quantitative identification system and an interval optimal frequency-speed system; segmented frequency slope control, accurate recognition of the crawling state, rolling line linkage speed increasing, temperature drop difference value correction and double-variable optimal control are achieved. The problems of scattered coil blowing, uneven cooling, high energy consumption and unstable quality caused by existing fixed parameter control are solved, it can be guaranteed that finished product coils are cooled evenly, the scattered coil distance is reasonable, the performance stability is improved, meanwhile, power consumption is saved, the production cost of ton steel is reduced, and the device is suitable for the double-high-wire finished product scattered coil cooling and conveying procedure of a steel rolling mill.

Description

Technical Field

[0001] This invention relates to the field of steel production technology, and in particular to a control method and system for intelligent matching of the frequency of the air-cooled roller conveyor fan and the speed of the roller conveyor. Background Technology

[0002] In the high-speed rolling mill production process, the air-cooled roller conveyor is a key piece of equipment connecting the rolling process and the finished product collection process. It undertakes two core functions: firstly, the function of transporting finished coils, which is to stably transport the finished coils formed by the coiler to the subsequent collection and packaging stages to ensure the continuity of the production process; secondly, the function of cooling finished coils, which uses airflow generated by fans installed under the air-cooled roller conveyor to cool down the high-temperature finished coils, so that the temperature of the coils is reduced to a range that meets the requirements of subsequent processing and performance, ensuring that the mechanical properties of the finished products meet the standards.

[0003] However, the current industry standard for controlling double-high-speed air-cooled roller conveyors generally adopts a fixed parameter mode, where the fan operates at a preset fixed frequency and the roller conveyor transmits at a fixed speed. This control method has significant drawbacks and technical defects, and has become a key bottleneck restricting production efficiency and finished product quality. The specific problems are as follows:

[0004] 1. Excessive blowing and cooling of loose coils can lead to abnormal performance and wasted energy.

[0005] Under the existing fixed control mode, the first section of the roller conveyor presents a contradiction: "excessive fan airflow + low roller conveyor speed." On the one hand, the airflow output from the fixed frequency converter exceeds the actual cooling requirements of the coiled rolls in this area. Excessive airflow can easily blow up the coiled rolls that have just entered the roller conveyor, causing disordered coil arrangement and affecting the stability of subsequent transmission. On the other hand, the low roller conveyor speed causes the coiled rolls to stay in this area for too long. Combined with the excessive airflow, this can lead to excessive cooling (excessive temperature drop), directly damaging the microstructure of the rolled piece and causing the mechanical properties (such as strength and toughness) of the finished product to deviate from the set standards, failing to meet usage requirements. At the same time, the continuous output of excess airflow does not require additional electrical energy, resulting in significant power waste and increasing the company's production costs.

[0006] 2. Uneven cooling of loose coils leads to unstable finished product quality and a decrease in yield:

[0007] Because the speed of the first section of the roller conveyor is fixed and relatively slow, the finished coils entering the conveyor cannot spread out quickly and evenly, easily resulting in stacking and overlapping. Under these conditions, the cooling airflow generated by the fan at a fixed frequency cannot evenly distribute the coils across all parts: the coils in the stacked areas suffer from insufficient cooling (temperature not reaching the target value) due to the difficulty in airflow penetration; while the exposed coils, directly subjected to the strong airflow, experience over-cooling (temperature too low), creating a double problem of uneven cooling: "local under-cooling + local over-cooling." This problem directly leads to a significant decrease in the stability of the finished product quality. Some abnormally cooled coils need to be scrapped, which not only increases raw material loss but also significantly reduces the yield rate and affects the consistency of the finished product batch quality.

[0008] 3. The speed and airflow are not properly coordinated, making it difficult to guarantee the cooling effect:

[0009] In the existing control mode, the frequency of the fan inverter and the speed of the roller conveyor are independent fixed parameters without any linkage adjustment mechanism. When production specifications (such as coil diameter and steel grade) change or operating conditions (such as rolling speed and coil temperature) fluctuate, the fixed air volume cannot adapt to the changed cooling requirements of the coil, and the fixed roller conveyor speed cannot adjust the transmission rhythm in accordance with the air volume, resulting in an imbalance between air volume and speed. For example, when the coil temperature is too high and stronger cooling is needed, the fixed air volume cannot meet the cooling requirements; when the coil temperature is normal but the roller conveyor speed is too slow, over-cooling will occur. This lack of linkage in the control method makes the cooling effect constantly unstable, making it difficult to ensure the consistency of the finished coil quality and further restricting the quality upgrade of high-speed wire rod products. Summary of the Invention

[0010] In order to overcome the above-mentioned shortcomings of the prior art, the purpose of this invention is to provide a control method and system for intelligent matching of the frequency of the high-speed wire rod air-cooling roller conveyor fan and the speed of the roller conveyor, which solves the defects of uneven cooling, low efficiency and high energy consumption of traditional high-speed wire rod air-cooling systems, while taking into account multiple requirements of product quality, production efficiency and cost control, and has strong operation and maintenance convenience and technical applicability.

[0011] The technical solution adopted by this invention to solve its technical problem is:

[0012] A control method for intelligently matching the frequency of a high-speed wire rod air-cooled roller conveyor fan with the roller conveyor speed, comprising the following steps:

[0013] S1: Set the frequency optimization control of the fan in the head section of the finished coil, set the frequency of the variable frequency fan after the finished coil is spun into a slope curve that drops evenly, and maintain the frequency at the end of the slope for constant frequency operation after a set time.

[0014] S2: Set the frequency optimization control of the fan in the middle and later sections of the finished coil. After the frequency constant frequency operation is set for a set time at the end of the slope in step S1, the frequency of the variable frequency fan is set to a uniformly rising slope curve until the initial frequency is reached.

[0015] S3: Set the fan frequency optimization control for the roller conveyor crawling time interval, accurately quantify and identify the crawling state of the roller conveyor, and then intelligently match and trigger the fan frequency to achieve optimal cooling matching control under the roller conveyor crawling state.

[0016] S4: Set up full-area intelligent speed-up control for the air-cooled roller conveyor, and add a linkage control unit between the air-cooled roller conveyor and the rolling line. When the pre-finishing steel signal is triggered, the full-area acceleration control of the air-cooled roller conveyor is started, and the acceleration amplitude is 1.5 times the initial setting.

[0017] S5: Set the initial speed control for gradient connection of the air-cooled roller conveyor, and add a time interval connection control unit. When the triggering link responds, the speed of the air-cooled roller conveyor will be reduced to the initial set speed that matches the rolling specifications according to the connection gradient.

[0018] S6: Set intelligent correction control for matching the fan frequency and roller speed range. By comparing the fan cooling range and the displacement range of the finished coil with the optimal range and outputting the difference, the optimal range control is achieved through intelligent correction with variable import.

[0019] S7: Set up interval temperature drop quantization identification and difference output control, add roller section interval quantization temperature identification unit, integrate with standard cooling control program to achieve efficient correction of cooling difference;

[0020] S8: Set the optimal frequency and speed control for the interval, add the optimal performance and optimal cooling curve control unit, and combine the combined control of fan frequency and roller speed to achieve dual optimal interval control of frequency control and speed control.

[0021] A control system for intelligently matching the frequency of the high-speed wire rod cooling roller conveyor fan and the speed of the roller conveyor to achieve the above control method includes a coil head frequency control and a mid-to-rear section fan control system, a roller conveyor crawling frequency optimization and a full-range speed-up control system, a gradient connection speed control and interval matching correction system, and an interval temperature drop identification and frequency-speed superposition control system.

[0022] The coil head frequency control and mid-to-rear section fan control system is used to execute the control of steps S1 and S2.

[0023] The roller conveyor crawling frequency optimization and global speed-up control system is used to execute the control of steps S3 and S4.

[0024] The gradient connection speed control and interval matching correction system is used to perform the control of steps S5 and S6.

[0025] The interval temperature drop identification and frequency-speed superposition control system is used to execute the control in steps S7 and S8.

[0026] As a further improvement of the present invention, the coil head frequency control and mid-to-rear section fan control system includes a coil head frequency control time interval interlocking control system, a coil head frequency control trigger signal control system, a coil head frequency control drive output control system, a mid-to-rear section fan control interval connection control system, a mid-to-rear section fan control interval superposition control system, and a mid-to-rear section fan control end-to-end lifting curve process control system.

[0027] As a further improvement of the present invention, the roller crawling frequency optimization and global acceleration control system includes a roller crawling frequency optimization state recognition control system, a roller crawling frequency optimization quantitative docking and matching control system, a roller crawling frequency optimization integrated output control system, a global acceleration control amplitude setting quantitative control system, a global acceleration control segmented matching and connection control system, and a global acceleration control intelligent triggering control system.

[0028] As a further improvement of the present invention, the gradient connection speed control and interval matching correction system includes a gradient connection speed control segmented interval coefficient control system, a gradient connection speed control initial value import control system, a gradient connection speed control integrated drive control system, an interval matching correction input drive control system, an interval matching correction output drive control system, and an interval matching correction parameter adjustment control system.

[0029] As a further improvement of the present invention, the interval temperature drop identification and frequency speed superposition control system includes an initial control system for interval temperature drop identification, an end control system for interval temperature drop identification, a variable conversion and processing control system for interval temperature drop identification, a combination output control system for frequency speed superposition control associated control points, a dual-variable linkage control system for frequency speed superposition control, and a drive output control system for frequency speed superposition control.

[0030] Compared with the prior art, the beneficial effects of the present invention are:

[0031] 1. Significantly improves the cooling uniformity of finished coils and ensures product quality stability: By segmented fan frequency control, roller crawling status recognition and interval temperature drop quantitative correction, the problem of uneven traditional air cooling is solved, ensuring a consistent temperature field for finished coils, improving mechanical property stability and reducing scrap rate.

[0032] 2. Optimize the speed control logic of the roller conveyor to improve production efficiency and the quality of loose coil arrangement: Relying on the full-range speed increase and gradient connection speed control of the rolling line linkage, the coil transmission time is shortened, loose coil stacking is avoided, downtime adjustment is reduced, and the overall efficiency of the rolling line is improved.

[0033] 3. Achieve precise energy consumption control and reduce the production cost per ton of steel: Break the constant power operation mode, match the fan frequency and roller speed as needed, reduce air cooling power consumption, and combined with the reduction of scrap rate, reduce the cost per ton of steel, which is in line with the trend of green manufacturing.

[0034] 4. Modular system design improves operation and maintenance convenience and enhances technical applicability: Modular design facilitates troubleshooting and maintenance, and the parameters are flexibly adjustable to adapt to different steel types and specifications, reducing the transformation cost of product switching. Attached Figure Description

[0035] Figure 1 This is a flowchart of a control method for intelligent matching of the frequency of a high-speed wire rod air-cooled roller conveyor fan and the speed of the roller conveyor, according to the present invention.

[0036] Figure 2 This is a structural block diagram of a control method for intelligent matching of the frequency of a high-speed wire rod air-cooled roller conveyor fan and the speed of the roller conveyor, according to the present invention. Detailed Implementation

[0037] The present invention will now be further described in conjunction with the accompanying drawings and embodiments:

[0038] like Figure 1 In this embodiment, the high-speed wire rod air-cooling roller conveyor is 60m long and divided into 8 segments (2.5m each). 16 variable frequency fans (rated power 7.5kW, rated frequency 50Hz) are installed below. The roller conveyor drive motor has a rated speed of 1450rpm and is suitable for rolling specifications Φ5mm-Φ20mm. It covers 20 common materials including Q235, 45# steel, and HRB400E. The following details the specific steps.

[0039] This embodiment discloses a control method for intelligent matching of the frequency of the air-cooled roller conveyor fan and the speed of the roller conveyor. The steps are as follows:

[0040] S1: Set up a frequency optimization control system for the fan in the head section of the finished coil. By setting the frequency of the variable frequency fan after the finished coil is spun into a uniformly decreasing slope curve, the frequency at the end of the slope can be protected after the time is set in the box to maintain constant frequency operation.

[0041] Preferably, after the finished rolled part is formed by the spinning machine (spinning speed 12-18 m / s), the head section control signal is triggered, and the fan frequency decreases uniformly from the initial value of 50 Hz at a slope of -0.5 Hz / s. After 10 seconds, it drops to the target frequency of 45 Hz and maintains this frequency for 20 seconds. During this stage, the air volume gradient is reduced (the air speed is simultaneously reduced from 9 m / s to 6 m / s) to prevent the loose rolled part that has just entered the roller table from being blown away by the strong airflow. At the same time, the temperature gradient of the rolled part in the head area is controlled to be ≤30℃ / m to prevent local overcooling.

[0042] Preferably, the slope parameter is set visually through a human-machine interface (HMI), and the input box supports step adjustment of 0.1-1.0Hz / s, which can be dynamically adjusted by the operator according to the thermal conductivity of the steel grade;

[0043] The frequency control integrates a PLC PID module (model S7-1500) to collect ambient temperature data in real time (range -10℃ to 40℃). When the ambient temperature fluctuates by ±10℃, the slope coefficient is automatically corrected (correction amount ±0.05Hz / s) to ensure a stable cooling rate.

[0044] The incidence of head-blown and blown-off accidents has been reduced from 15% in existing technologies to 1.2%, and the temperature uniformity in the head area has been improved by 40%.

[0045] S2: Set up a frequency optimization control system for the fan in the middle and later sections of the finished coil. After setting the time by setting the time of the set box, the frequency of the variable frequency fan is set to a uniformly rising slope curve until the initial frequency is reached.

[0046] Preferably, after 20 seconds of constant frequency operation in the head section, the frequency recovery program for the middle and rear sections is initiated: the fan frequency increases uniformly at a slope of +0.3Hz / s, and returns to the initial frequency of 50Hz after 16.7 seconds. During this stage, as the unrolled coil gradually unfolds on the roller conveyor (the coverage increases from 60% at the head to 85%), the air volume gradually increases to match the cooling requirements of the unrolled coil, and the temperature fluctuation of the unrolled coil in the end area is controlled within ±15℃ to avoid insufficient cooling in the middle and rear sections.

[0047] Preferably, the target frequency (45Hz) at the end of the slope is determined by a minimum amplitude algorithm, with the algorithm's marginal condition set as a roll density ≥ 1.2 rolls / m. 2 When the laser sensor detects that the unwound density is lower than this value, the constant frequency running time is automatically extended (for every decrease of 0.1 rolls / m). 2 (Extend for 2 seconds) to prevent overblowing from causing the roll to shift.

[0048] The rate of insufficient cooling in the middle and later stages of the coiling process was reduced from 20% to 3.5%, and the fluctuation range of the finished product's mechanical properties was reduced to ±5%.

[0049] S3: Set up a fan frequency optimization control system for the roller conveyor crawling time interval. By accurately quantifying and identifying the crawling state of the roller conveyor, the system then performs intelligent matching and triggering output of the fan frequency, thereby achieving optimal cooling matching control during the roller conveyor crawling state.

[0050] Preferably, the roller speed is detected in real time by an encoder (sampling frequency 1kHz, resolution 1μm). When the speed is ≤0.1m / s, the crawling mode is triggered and the fan frequency immediately drops to 30Hz. If the crawling duration is >5 seconds, the temperature difference compensation mechanism is activated: for every 1℃ higher than the standard value detected on the surface of the loose roll, the fan frequency increases by 2Hz (compensation upper limit 40Hz) to avoid local overheating of the loose roll during the crawling stage.

[0051] Preferably, the crawling state recognition module integrates a Hall sensor (detecting the roller conveyor motor current) and an AI classifier (based on the CNN algorithm, with 100,000 training samples and a recognition accuracy of ≥99%). Only when the current fluctuation is <5% and the speed is ≤0.1m / s is it determined to be a valid crawling state, thus avoiding false triggering caused by momentary motor stall.

[0052] The false trigger rate during crawling decreased from 8% to 0.3%, and the overheating rate during crawling phase decreased from 12% to 1.8%.

[0053] S4: Set up a full-area intelligent speed-up control system for the air-cooled roller conveyor. By adding a linkage control unit between the air-cooled roller conveyor and the rolling line, when the pre-finishing steel signal is triggered, the full-area acceleration control of the air-cooled roller conveyor is intelligently started, and the acceleration amplitude is quantized to 1.5 times the initial setting.

[0054] Preferably, when the current transformer of the 16 pre-finishing mill detects a sudden increase in the biting current of ≥50% (triggering a biting signal), the speed of the roller conveyor immediately increases from the initial value (e.g., 0.45m / s) to 1.5 times (0.675m / s), with an acceleration response time of <0.5 seconds, ensuring that the loose coils output from the rolling line can be quickly transmitted and avoiding roller conveyor congestion.

[0055] Preferably, the linkage control unit adopts the PROFINET communication protocol to establish real-time data interaction with the rolling line PLC (model S7-400), with a communication delay of <10ms. Simultaneously, an acceleration curve (S-curve, acceleration 0.5m / s²) is preset in the roller conveyor drive frequency converter (model MM440). 2 This prevents sudden speed changes from causing the rolls to unravel and stack.

[0056] The synchronization rate between the roller conveyor and the rolling line has been increased to 99.8%, and the accident rate of uncoiled coil congestion has been reduced by 95%.

[0057] S5: Set up an initial speed control system for gradient connection of air-cooled roller conveyor. By adding a time interval connection control unit, when the triggering link responds, the speed of the air-cooled roller conveyor is intelligently reduced to the initial set speed that matches the rolling specifications according to the connection gradient.

[0058] Preferably, when the rolling specification is changed (e.g., from Φ8mm to Φ12mm), the roller speed is automatically adjusted according to the gradient function V=0.2+0.05D (where D is the diameter of the rolled piece in mm): 0.6m / s for Φ8mm and 0.8m / s for Φ12mm, with a speed transition time of 3 seconds, to avoid unstable transmission of loose coils when the specification is changed.

[0059] Preferably, the gradient connection control unit has a built-in steel grade database that stores parameters such as thermal conductivity coefficient and phase transformation temperature of 20 common materials. When the steel grade is switched (e.g., Q235 is switched to 45# steel), the corresponding cooling curve is automatically called and the speed gradient is adjusted synchronously (e.g., the speed gradient of 45# steel is increased by 0.02m / s·mm).

[0060] When switching specifications, the rate of disordered roll arrangement decreased from 18% to 2.1%, and the switching transition time was shortened by 60%.

[0061] S6: Set up an intelligent correction control system for matching the fan frequency and roller speed range. By comparing the fan cooling range and the displacement range of the finished coil with the optimal range and outputting the difference, the optimal range control is achieved through intelligent correction of the variables.

[0062] This step achieves optimal interval matching through a three-level control system: "difference calculation - frequency correction - speed coordination," as detailed below:

[0063] Difference calculation module: A laser displacement sensor (accuracy ±0.5mm, sampling frequency 10Hz) is used to monitor the unwound displacement in real time, and compare it with the preset optimal displacement range (spacing 0.8-1.2m) to generate a displacement difference signal (unit mm);

[0064] Dynamic frequency correction: When the displacement difference exceeds the threshold (±50mm), the frequency correction algorithm is triggered, and the fan frequency is adjusted according to the gradient of Δf=0.1Hz / mm (correction range ±5Hz). For example, when the displacement difference is +60mm, the frequency increases by 6Hz.

[0065] Speed ​​coordination control: Synchronously adjust the roller speed (step 0.02m / s) to ensure uniform distribution of loose rolls (coverage ≥90%).

[0066] The corrected response time is ≤0.3 seconds, the temperature uniformity of unwinding is improved by 35% (the temperature difference is reduced from ±100℃ in the prior art to ±65℃), and the displacement deviation is controlled within ±30mm.

[0067] Preferably, the fan cooling zone is defined as a forced convection heat transfer area covering a roller conveyor width of 2-3m, with a wind speed control range of 6-12m / s, and the cooling efficiency satisfies a non-linear relationship with the wind speed: Q = 0.8v. 2 (Q is the cooling efficiency, v is the airflow speed);

[0068] Intelligent displacement range matching: Based on encoder (1μm resolution) and PID closed-loop control, a "position-frequency" mapping relationship is established by lookup table method or neural network fitting, and the error correction is <3%.

[0069] S7: Set up a temperature drop interval quantitative identification and difference output control system. By adding a roller conveyor segment interval quantitative temperature identification unit and integrating it with the standard cooling control program, the system can achieve efficient correction of cooling difference.

[0070] Preferably, this step achieves temperature drop uniformity control through zoned temperature measurement and dynamic correction, as detailed below:

[0071] Zoned temperature measurement: The 60m long roller conveyor is divided into 8 segmented sections (each segment is 2.5m), and each section is equipped with an infrared thermometer (wavelength 8-14μm, accuracy ±3℃) to collect the surface temperature of the unwound rolls in real time.

[0072] Temperature difference analysis: Calculate the difference between the temperature drop rate (°C / s) of each segment and the standard cooling curve in the steel grade database, and output the correction factor K (range 0.8-1.2). For example, when the actual temperature drop rate is 10% lower than the standard value, K = 0.9.

[0073] Integrated control: The K value is fed back to the fan frequency controller via PLC, and the output frequency is adjusted according to Δf = 2Hz × K to ensure consistent temperature drop in each section.

[0074] Key parameters and implementation results

[0075] The standard deviation of temperature drop uniformity decreased from 15℃ to 5℃, and the scrap rate of finished products decreased by 2.1% (from 5% to 2.9%).

[0076] Preferably, the segmented temperature recognition unit consists of a thermocouple array (0.5m spacing) and an infrared thermal imager, with a sampling frequency of 10Hz, and supports adaptive calibration of steel grades (such as compensation for the difference in cooling curves between 45# steel and Q235).

[0077] Difference output logic: A fuzzy PID algorithm is used. When the temperature difference is >30℃, a strong correction mode (frequency step size 1Hz) is activated, and when the temperature difference is <10℃, a fine-tuning mode (step size 0.2Hz) is activated to avoid overshoot during correction.

[0078] S8: Set up the interval optimal frequency and interval optimal speed control system. By adding the performance optimal and cooling curve optimal control unit and combining the combined control of fan frequency and roller speed, the dual optimal interval control of frequency control and speed control can be achieved.

[0079] Preferably, this step achieves dual optimization of "cooling-energy consumption" through bivariate optimization and real-time optimization, as detailed below:

[0080] Bivariate optimization: A three-dimensional mapping table of frequency-velocity (resolution 0.5Hz×0.01m / s) was established, with cooling efficiency η≥85% and fan energy consumption P≤40kW as constraints;

[0081] Real-time optimization: The optimal parameter combination is dynamically solved using a genetic algorithm (population size 50, iteration count 100). For example, for Φ10mm Q235 steel, the optimal solution is a frequency of 48Hz and a speed of 0.7m / s.

[0082] Closed-loop execution: Optimal parameters are sent to the frequency converter via PROFINET communication, with a response delay of <5ms.

[0083] Electricity consumption per ton of steel decreased by 18.7% (from 80kWh / t to 65kWh / t), and the finished product performance qualification rate increased to 99.2% (from 92% to 99.2 percentage points).

[0084] Preferred, highest-performance control unit: integrates JMatPro material simulation data and dynamically adjusts the cooling path according to the continuous cooling transition (CCT) curve to ensure that the unwinding phase transformation completion rate is ≥95%;

[0085] Cooling curve matching: Seven sets of reference curves are preset for Φ5-20mm specifications. The HMI interface allows operators to manually correct the curves by ±10% to adapt to special production needs.

[0086] like Figure 2 As shown, this invention further discloses a control system for intelligent matching of frequency and speed of high-speed wire rod air-cooled roller conveyor fan.

[0087] This includes a coil head frequency control and mid-to-rear section fan control system, a roller conveyor crawling frequency optimization and full-range speed increase control system, a gradient connection speed control and interval matching correction system, and an interval temperature drop identification and frequency-speed superposition control system.

[0088] The coil head frequency control and mid-to-rear section fan control system is used to first set up a finished coil head section fan frequency optimization control system. By setting the frequency of the variable frequency fan after the finished coil is unwinding to a uniformly decreasing slope curve, the frequency at the end of the slope can be protected and kept constant after a set time in the set box. Then, the finished coil mid-to-rear section fan frequency optimization control system is set up. By keeping the frequency at the end of the slope constant, the frequency of the variable frequency fan can be set to a uniformly increasing slope curve until the initial frequency is reached after a set time in the set box.

[0089] Preferably, the coil head frequency control and mid-to-rear section fan control system includes:

[0090] Interlocking module: Receives the trigger signal from the spinning machine (dry contact input, 24VDC) and triggers the head frequency slope control;

[0091] Signal generator: Outputs 0-10V analog signal to the frequency converter, corresponding to a fan frequency of 25-55Hz;

[0092] Redundancy design: Dual-channel PLC (master / standby switching time < 50ms) is used to prevent control interruption due to single point of failure.

[0093] The trigger signal system integrates a Hall effect sensor (sensitivity 20mV / G) and a current transformer (0-5A input). The head control is triggered only when the current of the spinning machine increases by ≥30% and the Hall sensor detects the passing of the workpiece, thus avoiding malfunctions.

[0094] The head control repeatability is ±0.2Hz, and the hardware failure rate is <0.1 times / year.

[0095] The frequency optimization control system for the head section of the finished coil refers to a frequency matching control system set up based on the segmented personalized control of the rolling section. "After the finished coil is produced" refers to the rolling state where the finished coil reaches the air-cooled roller conveyor for cooling and transport after passing through the coiler. A uniformly descending slope curve means controlling the entire frequency descent process according to a specific slope, thereby achieving better air-cooling control. The frequency optimization control system for the middle and rear sections of the finished coil refers to a frequency adaptive control system matched and set up based on the middle and rear sections of the rolling process. The frequency at the end of the slope refers to setting the frequency control point based on the minimum amplitude and the edge of the maximum time interval. The settable box setting time refers to achieving precise and adjustable control of the time variable by setting an import box on the human-machine interface and establishing connection points at the program control end.

[0096] The roller conveyor crawling frequency optimization and full-domain speed-up control system is used to first set up a fan frequency optimization control system for the roller conveyor crawling time interval. By accurately quantifying and identifying the crawling state of the roller conveyor, it then performs intelligent matching and triggering output of the fan frequency, thereby achieving optimal cooling matching control under the crawling state of the roller conveyor. Then, it sets up a full-domain intelligent speed-up control system for the air-cooled roller conveyor. By adding a linkage control unit between the air-cooled roller conveyor and the rolling line, when the pre-finishing 16 stands are triggered by a steel signal, the full-domain acceleration control of the air-cooled roller conveyor is intelligently started, and the acceleration amplitude is quantized to 1.5 times the initial setting.

[0097] Preferably, the roller conveyor crawling frequency optimization and global speed-up control system includes:

[0098] Status recognition unit: The speed of the roller conveyor is detected by an encoder (1024PPR). When the speed is <0.1m / s and lasts for 5 seconds, it is determined to be in a crawling state.

[0099] Frequency matching unit: calls the pre-stored parameter table (e.g., 30Hz creeping frequency corresponding to Φ12mm steel) and adjusts the frequency in combination with the temperature difference compensation algorithm;

[0100] Safety protection unit: When the crawling time is greater than 30 seconds, it will automatically switch to standby mode (fan frequency 15Hz, roller speed 0m / s) and trigger an audible and visual alarm.

[0101] The crawling frequency matching algorithm uses a sliding window mean filter (window width 10 seconds) to eliminate the interference of instantaneous fluctuations in roller speed (such as 0.1m / s→0.08m / s→0.12m / s), and the matching error is <1Hz.

[0102] The uniformity of cooling during the crawling stage is improved by 40%, and energy consumption is reduced by 22% (compared to fixed frequency control).

[0103] The roller conveyor crawling time interval fan frequency optimization control system refers to a system that identifies the special operating state of the air-cooled roller conveyor during crawling and then matches and controls the fan operating frequency accordingly.

[0104] Intelligent matching of fan frequency refers to the intelligent matching of the frequency of the fan in the air-cooled roller conveyor according to different operating conditions and time intervals.

[0105] Triggered output refers to a process output control system that controls based on triggering conditions and triggering thresholds. The intelligent speed-up control system for the entire air-cooled roller conveyor refers to a control system that uniformly and quantitatively increases the speed of all sections of the air-cooled roller conveyor.

[0106] The linkage control unit between the air-cooled roller conveyor and the rolling line refers to the system that identifies the control process and interval characteristics of the rolling line, and then performs associated drive control. The pre-finishing rolling 16-stand steel bite signal trigger refers to the signal triggering when the pre-finishing rolling 16-stand generates a bite current and triggers a bite distance interval.

[0107] The gradient connection speed control and interval matching correction system is used to first set up an initial speed control system for the gradient connection of the air-cooled roller conveyor. By adding a time interval connection control unit, when the triggering link responds, the speed of the air-cooled roller conveyor is intelligently reduced to the initial set speed that matches the rolling specifications according to the connection gradient. Then, an intelligent correction control system for the interval matching of the fan frequency and the roller conveyor speed is set up. The system compares the fan cooling interval and the displacement interval of the finished coil with the optimal interval and outputs the difference. Then, the optimal interval control is achieved through intelligent correction of the variables.

[0108] The initial speed control system for gradient connection of air-cooled roller conveyors refers to setting initial values ​​for the control speed of each section of the air-cooled roller conveyor according to different rolling specifications and steel grades, thereby achieving optimal control of the coil arrangement.

[0109] The time interval connection control unit refers to a system that performs cross-connection and superposition fusion control on different sections of the rolling process and different time intervals of the air cooling control process.

[0110] The intelligent correction control system for matching the fan frequency and roller conveyor speed range refers to a process control system that matches the fan frequency and roller conveyor speed range based on the optimal control curve of the controlled cooling process of the air-cooled roller conveyor.

[0111] The fan cooling zone refers to the quantified temperature reduction achieved through air-cooled fans. The finished coil displacement zone refers to the control system set up based on the coil movement and position movement records.

[0112] The interval temperature drop identification and frequency-speed superposition control system is used to first set up an interval temperature drop quantization identification and difference output control system. By adding a roller conveyor segmented interval quantization temperature identification unit and integrating it with the standard cooling control program, efficient correction of cooling difference can be achieved. Then, an interval optimal frequency and interval optimal speed control system is set up. By adding a performance optimal and cooling curve optimal control unit and combining it with the combined control of fan frequency and roller conveyor speed, dual optimal interval control of frequency control and speed control can be achieved.

[0113] The temperature drop quantification and difference output control system refers to a comprehensive output control system based on the quantification and difference identification of temperature in different loose roll transportation sections.

[0114] The roller conveyor segmented temperature identification unit refers to a control system that independently identifies the temperature of each transmission segment of the air-cooled roller conveyor, enabling matched control adjustment and intelligent correction. The optimal frequency and speed control system for each segment refers to a matched variable control system designed based on optimal temperature transition control and optimal cooling speed control. The optimal performance and optimal cooling curve control unit refers to a control system that achieves optimal control of the cooling of finished coils by bidirectionally identifying performance characteristics and variable range curves and correcting for differences.

[0115] Example verification and technical advantages:

[0116] This invention was validated for three months on a double high-efficiency production line (annual output of 800,000 tons) in a steel plant. The results showed that:

[0117] Uniformity of cooling of finished loose coils: the temperature difference decreased from ±100℃ to ±65℃, an improvement of 35%;

[0118] Finished product yield: The scrap rate decreased from 5% to 2.9%, an increase of 2.1 percentage points, resulting in an annual economic benefit of approximately 1.2 million yuan;

[0119] Energy consumption: Electricity consumption per ton of steel decreased from 80 kWh / t to 65 kWh / t, saving 12 million kWh of electricity per year, equivalent to approximately 8.4 million yuan in electricity costs;

[0120] Stability: The system can operate continuously without failure for more than 1,000 hours, and the control response time is ≤0.5 seconds, meeting the needs of industrial production.

[0121] Compared with existing fixed parameter control technologies, this invention achieves dynamic optimal matching between fan frequency and roller speed through segmented control, linkage adjustment and intelligent correction, while taking into account cooling effect, production efficiency and energy consumption control, and has significant technological innovation and industrial application value.

[0122] In summary, after reading this invention document, those skilled in the art can make various other corresponding modifications to the technical solutions and concepts based on this invention without creative mental effort, and all of these modifications fall within the scope of protection of this invention.

Claims

1. A control method for intelligent matching of the frequency of a high-speed wire rod air-cooled roller conveyor fan and the speed of the roller conveyor, characterized in that, Includes the following steps: S1: Set the frequency optimization control of the fan in the head section of the finished coil, set the frequency of the variable frequency fan after the finished coil is spun into a slope curve that drops evenly, and maintain the frequency at the end of the slope for constant frequency operation after a set time. S2: Set the frequency optimization control of the fan in the middle and later sections of the finished coil. After the frequency constant frequency operation is set for a set time at the end of the slope in step S1, the frequency of the variable frequency fan is set to a uniformly rising slope curve until the initial frequency is reached. S3: Set the fan frequency optimization control for the roller conveyor crawling time interval, accurately quantify and identify the crawling state of the roller conveyor, and then intelligently match and trigger the fan frequency to achieve optimal cooling matching control under the roller conveyor crawling state. S4: Set up full-area intelligent speed-up control for the air-cooled roller conveyor, and add a linkage control unit between the air-cooled roller conveyor and the rolling line. When the pre-finishing steel signal is triggered, the full-area acceleration control of the air-cooled roller conveyor is started, and the acceleration amplitude is 1.5 times the initial setting. S5: Set the initial speed control for gradient connection of the air-cooled roller conveyor, and add a time interval connection control unit. When the triggering link responds, the speed of the air-cooled roller conveyor will be reduced to the initial set speed that matches the rolling specifications according to the connection gradient. S6: Set intelligent correction control for matching the fan frequency and roller speed range. By comparing the fan cooling range and the displacement range of the finished coil with the optimal range and outputting the difference, the optimal range control is achieved through intelligent correction with variable import. S7: Set up interval temperature drop quantization identification and difference output control, add roller section interval quantization temperature identification unit, integrate with standard cooling control program to achieve efficient correction of cooling difference; S8: Set the optimal frequency and speed control for the interval, add the optimal performance and optimal cooling curve control unit, and combine the combined control of fan frequency and roller speed to achieve dual optimal interval control of frequency control and speed control.

2. A control system for intelligently matching the frequency of a high-speed wire rod air-cooled roller conveyor fan with the speed of the roller conveyor to implement the control method described in claim 1, characterized in that, This includes a coil head frequency control and mid-to-rear section fan control system, a roller conveyor crawling frequency optimization and full-range speed increase control system, a gradient connection speed control and interval matching correction system, and an interval temperature drop identification and frequency speed superposition control system. The coil head frequency control and mid-to-rear section fan control system is used to execute the control of steps S1 and S2. The roller conveyor crawling frequency optimization and global speed-up control system is used to execute the control of steps S3 and S4. The gradient connection speed control and interval matching correction system is used to perform the control of steps S5 and S6. The interval temperature drop identification and frequency-speed superposition control system is used to execute the control in steps S7 and S8.

3. The control system according to claim 2, characterized in that, The coil head frequency control and mid-to-rear section fan control system includes a coil head frequency control time interval interlocking control system, a coil head frequency control trigger signal control system, a coil head frequency control drive output control system, a mid-to-rear section fan control interval connection control system, a mid-to-rear section fan control interval superposition control system, and a mid-to-rear section fan control end-to-end lifting curve process control system.

4. The control system according to claim 2, characterized in that, The roller conveyor crawling frequency optimization and global acceleration control system includes a roller conveyor crawling frequency optimization state recognition control system, a roller conveyor crawling frequency optimization quantitative docking and matching control system, a roller conveyor crawling frequency optimization integrated output control system, a global acceleration control amplitude setting quantitative control system, a global acceleration control segmented matching and connection control system, and a global acceleration control intelligent triggering control system.

5. The control system according to claim 2, characterized in that, The gradient connection speed control and interval matching correction system includes a gradient connection speed control segmented interval coefficient control system, a gradient connection speed control initial value import control system, a gradient connection speed control integrated drive control system, an interval matching correction input drive control system, an interval matching correction output drive control system, and an interval matching correction parameter adjustment control system.

6. The control system according to claim 2, characterized in that, The interval temperature drop identification and frequency-velocity superposition control system includes an initial control system for interval temperature drop identification, an end control system for interval temperature drop identification, a variable conversion and processing control system for interval temperature drop identification, a combination output control system for frequency-velocity superposition control associated control points, a dual-variable linkage control system for frequency-velocity superposition control, and a drive output control system for frequency-velocity superposition control.

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