Converter blowing signal linkage og fan high-low speed control method and system

Abstract

This invention relates to the field of OG blower speed control technology, specifically to a method and system for high and low speed control of OG blowers linked to converter blowing signals. The method includes the converter PLC acquiring the oxygen lance height value, oxygen valve status, and nitrogen valve status and sending them to the OG blower PLC. The OG blower PLC generates speed commands based on the comparison between the oxygen lance height value and the blowing position threshold, as well as the oxygen and nitrogen valve statuses. A high-speed command is generated when the oxygen lance height value is lower than the blowing position threshold and the oxygen valve is open; otherwise, a low-speed command is generated. When the speed command changes, a ramp function is used to linearly change the blower speed from the initial speed to the target speed within a 120-second buffer time, and a current signal is output to drive the hydraulic coupler actuator to adjust the blower speed. This invention achieves automatic segmented operation of the blower speed according to the converter process, while mitigating equipment impact through buffer control, resulting in good energy-saving effects and equipment protection.

Description

Technical Field

[0001] This invention relates to the field of OG blower speed control technology, and more specifically, to a method and system for controlling the high and low speeds of OG blowers in converter blowing signal linkage. Background Technology

[0002] In the converter steelmaking process, the OG blower, as the core equipment of the gas recovery system, is mainly used to extract the high-temperature flue gas generated during converter smelting. OG stands for oxygen converter gas recovery. This blower is usually driven by a high-voltage motor and uses a hydraulic coupler to achieve speed regulation. Operators rely on experience to manually adjust the electric actuator of the coupler to keep the blower running at high speed during the blowing stage to meet the gas extraction process requirements.

[0003] However, converter smelting is an intermittent process, requiring high-speed operation of the blowers only during the blowing stage, while other stages do not require high speed. Because manual adjustment cannot precisely match the changes in the converter process, operators often keep the blowers running at high speed throughout the entire smelting cycle, resulting in a large amount of wasted electricity during non-blowing stages.

[0004] To address the aforementioned issues, existing technologies have proposed a PID control scheme based on flue gas parameter feedback. This scheme uses a pressure sensor or flow meter to detect the flue gas pressure or flow rate at the OG fan inlet in real time, compares the detected value with the set value, and uses a PID algorithm to calculate the output control quantity to adjust the hydraulic coupler actuator, thereby automatically changing the fan speed.

[0005] However, this method has certain limitations: its control source is flue gas parameters rather than core converter process signals, so it can only respond after flue gas parameters change, making it impossible to predict the start and end of converter blowing in advance, and also difficult to distinguish between different process stages such as blowing and slag splashing for furnace protection; at the same time, this scheme adopts a direct step adjustment method when switching the fan speed, which does not fully consider the dynamic response characteristics of high-power equipment and hydraulic couplers, and is prone to causing mechanical and electrical shocks to the fan system.

[0006] Therefore, there is an urgent need for an OG blower control method that can be linked with converter blowing process signals and has smooth speed regulation function. Summary of the Invention

[0007] One objective of this invention is to provide a method for controlling the high and low speeds of the OG blower in a converter blowing process, which uses the oxygen lance position and oxygen valve status as core process signals to effectively identify the blowing and non-blowing stages and generate corresponding speed commands. Simultaneously, it employs buffer control during speed switching to ensure smooth changes in blower speed, thereby solving the problems mentioned in the background art. Manual adjustment cannot accurately match the intermittent process changes of the converter, causing the blower to continue to run at high speed during non-blowing stages, resulting in energy waste. Furthermore, the existing automatic speed control scheme has problems such as response lag, difficulty in distinguishing different process stages, and the risk of equipment shock when speed changes abruptly.

[0008] To achieve the above objective, the method includes the following steps: S1. The converter PLC collects the oxygen lance height value output by the absolute encoder on the oxygen lance lifting mechanism, the oxygen blowing valve status output by the valve position feedback switch on the oxygen blowing valve, and the nitrogen blowing valve status output by the valve position feedback switch on the nitrogen blowing valve, and sends them to the OG blower PLC via industrial Ethernet. S2. Preset the blowing position threshold, compare the oxygen lance height value with the blowing position threshold, and generate a speed command based on the comparison result and the status of the oxygen and nitrogen valves: When the oxygen lance height is below the blowing position threshold and the oxygen valve is open, a high-speed command is generated. When the oxygen lance height is below the blowing position threshold and the nitrogen blowing valve is open, a low-speed command is generated. When the oxygen lance height value is not lower than the blowing position threshold, a low-speed command is generated; The S3 and OG fan PLC uses the speed command as the target speed and the current actual speed of the fan as the starting speed, and sets the buffer time to 120 seconds. During the buffer time, each control cycle calculates the time elapsed from the start of the buffer. Multiply the ratio of this time to the buffer time by the difference between the target speed and the starting speed, and then add the starting speed to obtain the speed that should be reached in the current cycle. Based on the linear correspondence between the expected speed and the current value, a current signal corresponding to the expected speed in the current cycle is generated and output to the hydraulic coupler actuator. S4. The electric actuator drives the scoop tube to move according to the current signal, changing the amount of oil filling the working chamber of the hydraulic coupler. The change in the amount of oil filling adjusts the speed of the fan connected to the output end of the hydraulic coupler.

[0009] In the above technical solution, the oxygen lance height and the oxygen blowing valve status are used as triggering conditions for high-speed commands because the oxygen lance position directly reflects whether the converter has entered the blowing preparation state, while the opening of the oxygen blowing valve marks the actual start of blowing. Both conditions must be met simultaneously to ensure that the blower immediately accelerates at the start of blowing, avoiding the inherent lag problem of relying solely on flue gas parameter feedback. Simultaneously, the nitrogen blowing valve status is used as a separate condition for low-speed commands because during the slag splashing and furnace protection stage, although the oxygen lance is in the blowing position, gas recovery is not required. Failure to distinguish this would lead to incorrect blower acceleration and energy waste. The nitrogen blowing valve status accurately identifies this stage and maintains low-speed blower operation. Furthermore, a 120-second buffer time is set when the speed command switches, and a ramp function linear speed regulation is used because high-power blowers and... Hydraulic couplers have large rotational inertia and mechanical inertia. Direct step switching can cause severe mechanical and electrical shocks, which can accelerate equipment wear or even cause fan surge or coupler overheating. Linear speed regulation, on the other hand, can match the speed change process with the dynamic response characteristics of the equipment, thereby achieving a safe and smooth transition. Based on this, by establishing a precise mathematical relationship between the calculation of the speed to be reached in the current cycle and the buffer time, that is, the speed to be reached in each control cycle is obtained by adding the ratio of the starting speed to the buffer time and multiplying it by the speed difference, the fan speed can be accurately completed in the predetermined time. This ensures the smoothness of speed regulation and achieves stable control of the speed regulation time, avoiding the problems of excessively long speed regulation time affecting the process response or excessively short speed regulation time causing equipment shock.

[0010] Based on this, the electric actuator drives the scoop tube to move axially. When the scoop tube is inserted into the working chamber of the hydraulic coupler, the amount of oil in the working chamber decreases, causing the fan speed to decrease. When the scoop tube is pulled out, the amount of oil in the working chamber increases, causing the fan speed to increase.

[0011] In another technical solution, when the speed command of the OG fan PLC changes, if another command switch occurs during the buffering process, the current actual speed is used as the new starting speed and the current time is used as the new starting time to restart the buffer control.

[0012] In this technical solution, the electric actuator drives the scoop tube to move axially to adjust the oil filling volume of the hydraulic coupler's working chamber. This is because the speed regulation principle of the hydraulic coupler determines that its output speed is positively correlated with the oil filling volume of the working chamber. By changing the position of the scoop tube, the fan speed can be continuously and steplessly adjusted. This combination of mechanical structure and control signal allows the 4-20mA current signal to be directly converted into the displacement of the scoop tube, thus ensuring the accurate execution of the speed regulation command. If the correspondence between the scoop tube's movement direction and the speed change is not clearly defined, the operator or control system may cause the speed regulation direction to be incorrect due to confusion, which may even damage the equipment in severe cases. Based on this, when another instruction switch occurs during the buffering process, the current actual speed is used as the new starting speed to restart the buffering control. This is because the converter smelting process may experience short-term interruptions or rapid changes, such as the oxygen blowing valve being closed briefly and then immediately opened. If the original buffering process is continued, the blower speed may become out of sync with the process requirements. Restarting the buffering control ensures that the blower always transitions to the new target speed from the current actual speed, which not only ensures that the blower speed follows the process changes in real time, but also ensures that any switching process is carried out smoothly under the buffering control.

[0013] The second objective of this invention is to provide a converter blowing signal linkage OG blower high and low speed control system, including a signal acquisition and communication module, a process stage identification module, a buffer control module, an actuator module, and a human-machine interaction module; The signal acquisition and communication module is used to acquire oxygen lance height values, oxygen blowing valve status, and nitrogen blowing valve status, and send the acquired oxygen lance height values, oxygen blowing valve status, and nitrogen blowing valve status to the OG blower PLC via industrial Ethernet. The process stage identification module is used to generate speed commands based on the oxygen lance height value, oxygen blowing valve status, and nitrogen blowing valve status. The buffer control module is used to take the speed command as the target speed and the current actual speed of the fan as the starting speed. Within a 120-second buffer period, it calculates the expected speed for each control cycle according to the ramp function, so that the expected speed changes linearly from the starting speed to the target speed, and converts the expected speed into a current signal output. The actuator module is used to drive the scoop tube to move according to the current signal, change the oil filling amount of the hydraulic coupler working chamber, and thus adjust the fan speed; The human-machine interaction module is used to receive operating status data sent by the OG fan PLC and display it through a graphical interface, as well as to receive manual commands input by the operator and send them to the OG fan PLC.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention achieves effective linkage between the oxygen lance position and the oxygen blowing valve status, automatically increasing the speed of the blower to high speed during the converter blowing stage to ensure the gas recovery effect, and automatically reducing the speed of the blower to low speed during the non-blowing stage, thus avoiding the energy waste caused by the blower maintaining high speed during the non-blowing stage in traditional manual operation.

[0015] 2. This invention sets a 120-second buffer time and uses a ramp function for linear speed regulation when switching speed commands, so that the fan speed changes smoothly from the starting speed to the target speed. This avoids the mechanical and electrical shocks to the fan and power grid caused by direct step switching, effectively preventing equipment failures such as fan surge, hydraulic coupling overheating and motor overload, and extending the service life of key equipment.

[0016] 3. This invention enables data exchange between the converter PLC and the OG blower PLC via industrial Ethernet, allowing the blower speed to be automatically adjusted in real time to follow changes in the converter process. At the same time, it provides automatic and manual dual-mode operation through the WINCC human-machine interface. Operators can achieve intelligent operation without human intervention by centrally monitoring in the main control room, and can also flexibly intervene manually under special working conditions, which greatly reduces the labor intensity and risk of misoperation of on-site manual operation. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall process of the converter blowing signal linkage OG blower high and low speed control method of the present invention; Figure 2 This is a flowchart of step S2 of the present invention; Figure 3 This is a flowchart of step S3 of the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Here are some explanations of technical terms: Wherein, PLC stands for Programmable Logic Controller. In this embodiment, it includes a converter PLC installed in the converter main control room and an OG blower PLC installed in the OG blower room control cabinet, which are used to collect converter-side process signals and execute blower control algorithms, respectively. A WINCC industrial computer refers to an industrial control computer installed with Siemens WINCC configuration software, used to realize the display and operation of the human-machine interface; A hydraulic coupler actuator is an electric actuator installed on the housing of a hydraulic coupler, used to drive the movement of the scoop tube.

[0020] Currently, manual adjustment cannot accurately match the intermittent process changes in the converter, resulting in the blower maintaining high-speed operation during non-blowing stages, leading to energy waste. Furthermore, existing automatic speed control schemes suffer from response lag, difficulty in distinguishing different process stages, and the potential for equipment shock during abrupt speed changes. One objective of this invention is to provide a method for controlling the high and low speeds of the OG blower in conjunction with converter blowing signals. See [link to relevant documentation]. Figure 1 As shown, it includes the following steps: S1. The converter PLC collects the oxygen lance height value output by the absolute encoder on the oxygen lance lifting mechanism, the oxygen blowing valve status output by the valve position feedback switch on the oxygen blowing valve, and the nitrogen blowing valve status output by the valve position feedback switch on the nitrogen blowing valve, and sends them to the OG blower PLC via industrial Ethernet. S2. Preset the blowing position threshold, compare the oxygen lance height value with the blowing position threshold, and generate a speed command based on the comparison result and the status of the oxygen and nitrogen valves: When the oxygen lance height is below the blowing position threshold and the oxygen valve is open, a high-speed command is generated. When the oxygen lance height is below the blowing position threshold and the nitrogen blowing valve is open, a low-speed command is generated. When the oxygen lance height value is not lower than the blowing position threshold, a low-speed command is generated; The S3 and OG fan PLC uses the speed command as the target speed and the current actual speed of the fan as the starting speed, and sets the buffer time to 120 seconds. During the buffer time, each control cycle calculates the time elapsed from the start of the buffer. Multiply the ratio of this time to the buffer time by the difference between the target speed and the starting speed, and then add the starting speed to obtain the speed that should be reached in the current cycle. Based on the linear correspondence between the expected speed and the current value, a current signal corresponding to the expected speed in the current cycle is generated and output to the hydraulic coupler actuator. S4. The electric actuator drives the scoop tube to move according to the current signal, changing the amount of oil filling the working chamber of the hydraulic coupler. The change in the amount of oil filling adjusts the speed of the fan connected to the output end of the hydraulic coupler.

[0021] By linking the oxygen lance position with the oxygen blowing valve status signal in real time, and combining it with buffer speed control tailored to the characteristics of the hydraulic coupler, the fan speed and converter smelting conditions are precisely matched. This minimizes energy consumption while ensuring process requirements are met, and effectively protects the safe operation of the equipment.

[0022] The equipment layout of this invention involves equipment in two areas: the converter side and the blower room side. The converter side is provided with a converter body, and a liftable oxygen lance is provided above the converter body. The oxygen lance is driven to move up and down by an oxygen lance lifting mechanism. An absolute encoder is installed on the oxygen lance lifting mechanism, which is used to detect the height position of the oxygen lance in real time.

[0023] The converter side is also equipped with oxygen blowing valves and nitrogen blowing valves. The oxygen blowing valve is installed on the oxygen delivery pipeline, and the nitrogen blowing valve is installed on the nitrogen delivery pipeline. Each of the oxygen blowing valves and nitrogen blowing valves is equipped with a valve position feedback switch to detect the open and closed status of the valves. The absolute encoder of the oxygen lance lifting mechanism, the valve position feedback switch of the oxygen blowing valve, and the valve position feedback switch of the nitrogen blowing valve are all connected to the converter PLC via signal cables. The converter PLC is located in the converter main control room.

[0024] An OG fan is installed on the fan room side. The OG fan is driven by a high-power, high-voltage motor. The motor output shaft is connected to the fan input shaft via a hydraulic coupler, which is used to regulate the fan speed. An electric actuator is installed on the hydraulic coupler. The electric actuator contains a motor and a transmission mechanism, which drives the movement of the scoop tube inside the hydraulic coupler. The fan speed is regulated by changing the amount of oil filling the working chamber.

[0025] The control signal input terminal of the electric actuator is connected to the OG fan PLC via a control cable. The OG fan PLC is located in the control cabinet of the OG fan room. A WINCC industrial computer is also installed on the fan room side. The WINCC industrial computer serves as the human-machine interface and is connected to the OG fan PLC via Ethernet for human-machine interaction and monitoring of operating status.

[0026] Based on the completed equipment layout, this invention establishes a data communication link between the converter PLC and the OG blower PLC. An optical fiber cable is laid between the Ethernet communication modules of the converter PLC and the OG blower PLC, with both ends connected to industrial Ethernet switches. The WINCC industrial control computer in the converter main control room is connected to the local switch via a network cable, and the WINCC industrial control computer in the OG main control room is connected to the blower room switch via a network cable, forming a complete industrial Ethernet network. Fixed IP addresses on the same network segment are assigned to each device in the network, and subnet masks and gateway parameters are set to ensure network connectivity.

[0027] The converter PLC and the OG blower PLC use a periodic data exchange method. The converter PLC packages the collected oxygen lance position signal, oxygen valve status signal, and nitrogen valve status signal into data and sends it to the OG blower PLC via Ethernet. The OG blower PLC sends its operating status data to the converter PLC and two WINCC industrial control computers via Ethernet, realizing bidirectional data exchange and centralized monitoring.

[0028] Based on the above equipment layout and communication link establishment, the following describes the working process of the oxygen lance during converter smelting. A complete converter smelting cycle consists of multiple stages: In the initial stage, the oxygen lance is at its upper limit position, during which iron addition and scrap steel addition operations are performed; subsequently, the oxygen lance descends to the blowing position, the oxygen valve opens to begin blowing, and the converter generates a large amount of flue gas during this stage, requiring the OG blower to operate at high speed to ensure gas recovery; after blowing, the oxygen lance is raised to the waiting position, the oxygen valve closes, and operators perform temperature measurement and sampling; subsequently, the oxygen lance is raised to its upper limit again for steel tapping; finally, the oxygen lance descends to the blowing position again, the nitrogen valve opens for slag splashing and furnace protection, and gas recovery is not required during this stage, with the blower operating at low speed. During the above process, the positional changes of the oxygen lance and the on / off states of the oxygen and nitrogen valves are key signals for determining the current process stage of the converter.

[0029] Step S1 of this invention involves process signal acquisition and transmission. Specifically, the converter PLC acquires core process signals from the converter side in real time and periodically sends the acquired signals to the OG blower PLC using the established industrial Ethernet communication link, providing a data foundation for subsequent process stage identification. This includes the following steps: Ⅰ: During the operation of the oxygen lance lifting mechanism, the absolute encoder installed on it outputs a communication signal in real time. This signal has a linear relationship with the height position of the oxygen lance. The converter PLC reads this signal through PROFIBUS at a fixed sampling period.

[0030] The converter PLC has an internal data conversion function that converts the acquired digital signal values ​​into actual oxygen lance height values ​​in meters. The sampling period is set to 100ms to ensure real-time tracking of oxygen lance position changes. Simultaneously, the converter PLC filters the signal to eliminate potential transient interference and ensure the stability of the acquired data.

[0031] II: Each oxygen and nitrogen blowing valve is equipped with a valve position feedback switch. When the valve is open, the feedback switch outputs a closed signal, and the corresponding digital input channel of the converter PLC detects a high level. When the valve is closed, the feedback switch outputs an open signal, and the corresponding channel is at a low level. The converter PLC scans each digital input channel at a fixed cycle to obtain the real-time on / off status of the oxygen and nitrogen blowing valves, thus determining their respective statuses.

[0032] To prevent misjudgment of valve status due to valve vibration or electromagnetic interference on site, the converter PLC sets delay filtering for the two valve statuses: only when a certain status remains stable for more than 200ms will it be recognized as a valid status and used for subsequent logic judgment.

[0033] III: The converter PLC packages the pre-processed oxygen lance height, oxygen valve status, and nitrogen valve status into a single data packet according to a pre-defined data format. This data packet contains a data identifier, timestamp, and data value. Using Ethernet communication, the converter PLC sends this data packet to the designated receiving area of ​​the OG blower PLC every 200ms. The transmission employs a periodic triggering method to ensure the timeliness and stability of data updates.

[0034] IV: After receiving the data packet sent by the converter PLC, the OG blower PLC first checks the data freshness. An internal timer is set in the OG blower PLC, resetting after each successful reception of new data. If no new data packet is received for 500 ms, communication is considered interrupted. In this case, the OG blower PLC automatically maintains the current blower speed and issues a communication fault alarm.

[0035] If data reception is normal, the OG blower PLC will store the received oxygen lance height, oxygen valve status, and nitrogen valve status into its local data area, and perform a validity check on the oxygen lance height value to determine if it is within the preset normal range. If it exceeds this range, the data is considered invalid, and the valid value from the previous cycle is used instead. At the same time, a data anomaly warning is issued, prompting the operator to check the encoder or signal lines.

[0036] Through the above steps, the OG blower PLC can obtain stable and reliable converter process signals in real time, laying the foundation for subsequent process stage identification.

[0037] like Figure 2 As shown, step S2 of this invention involves process stage identification and speed command generation. Specifically, the OG blower PLC identifies the current process stage of the converter based on the received oxygen lance height value, oxygen valve status, and nitrogen valve status, according to a preset judgment logic, and generates a corresponding blower speed command based on the process stage. This includes the following steps: I: The OG blower PLC has a pre-set blowing position height threshold. This threshold is set according to the actual process parameters of the converter. When the oxygen lance height is below this threshold, it is determined that the oxygen lance has entered the blowing position. Simultaneously, the OG blower PLC has internal timers for oxygen valve opening and closing to record the duration of the oxygen valve's state. The OG blower PLC also has a preset minimum oxygen blowing duration required for determining the blowing stage to prevent misjudgments caused by instantaneous signal fluctuations.

[0038] II: The OG blower PLC reads the currently received oxygen lance height, oxygen valve status, and nitrogen valve status in each control cycle. When the oxygen lance height is lower than the preset blowing position threshold and the oxygen valve is open, the oxygen valve opening timer starts accumulating. When the oxygen valve opening duration reaches the preset minimum oxygen blowing duration, the OG blower PLC determines that the converter is currently in the blowing stage, at which point a high-speed operation command is generated, with the target speed set to 1200 r / min. The duration requirement in the blowing stage determination condition is to avoid misjudgments caused by abnormal operating conditions such as the oxygen valve opening briefly and then immediately closing.

[0039] III: When the oxygen lance height is below the preset blowing position threshold and the nitrogen valve is open, the OG blower PLC determines that the converter is currently in the slag splashing protection stage. Although the oxygen lance is also in the blowing position during the slag splashing protection stage, the nitrogen valve is open for slag splashing operation, and gas recovery is not required. Therefore, the OG blower PLC generates a low-speed operation command, with the target speed set to 800 r / min. The slag splashing protection stage is identified separately and maintained at a low speed to avoid energy waste caused by accidental speed increases during this stage.

[0040] When the oxygen lance height is higher than the preset blowing position threshold, or when both the oxygen and nitrogen valves are closed, the OG blower PLC determines that the converter is currently in a non-blowing stage. The non-blowing stage includes processes such as ferroalloy addition, scrap steel addition, temperature measurement and sampling, tapping, and waiting. These stages do not require gas recovery; therefore, the OG blower PLC generates a low-speed operation command, setting the target speed to 800 r / min.

[0041] IV: After executing the above judgment logic each cycle, the OG blower PLC stores the generated speed command in the output register and records the current command value for comparison in the next cycle. If the judgment results are consistent for multiple consecutive cycles, the speed command remains unchanged; if the judgment result changes, the speed command switches accordingly, and the buffer control process is triggered in the next cycle. The OG blower PLC also stores key data such as the currently identified process stage, oxygen lance height, and valve status in the local data area for display on the human-machine interface and subsequent analysis.

[0042] Through the above steps, the OG blower PLC can accurately identify the current process stage based on the real-time process signals of the converter and generate a matching blower speed command, laying the foundation for achieving precise on-demand energy supply.

[0043] like Figure 3As shown, step S3 of this invention is speed command switching and buffer control. Specifically, the OG fan PLC detects whether the speed command has changed. When a switch occurs, the buffer control algorithm is activated. A ramp function smoothly transitions the current speed to the target speed within a preset time, and the intermediate value is converted into an analog signal in real time and output to the hydraulic coupler actuator. The specific steps include: Ⅰ: In each control cycle, the OG fan PLC compares the speed command generated in the current cycle with the speed command recorded in the previous cycle. If the two values ​​are equal, it is determined that the speed command has not changed, and the current output value remains unchanged; if the two values ​​are not equal, it is determined that a command switch has occurred, and the switch buffer start time T0 and the starting speed n0 are recorded, where n0 is the current actual speed value of the fan, and the buffer control process is started.

[0044] The instruction switching includes two scenarios: the acceleration process of switching from a low-speed instruction of 800 r / min to a high-speed instruction of 1200 r / min, and the deceleration process of switching from a high-speed instruction of 1200 r / min to a low-speed instruction of 800 r / min.

[0045] Furthermore, the OG fan PLC has a pre-set buffer time T of 120 seconds. This buffer time is determined based on the response characteristics of the hydraulic coupler actuator, the rotational inertia of the high-power fan, and actual on-site commissioning experience. It ensures that the fan speed changes smoothly, avoiding impact on the equipment and power grid, while also meeting the requirements of the converter smelting process for the fan's response speed.

[0046] II: After the buffer control is started, the OG fan PLC calculates the expected speed at the current moment according to the ramp function in each control cycle. The ramp function expression is: ; In the formula, n(t) is the expected rotational speed at the current moment; n0 is the initial rotational speed during buffer startup; n t The target speed is 1200 r / min during acceleration and 800 r / min during deceleration. T is the preset buffer time, which is 120 seconds. T0 is the buffer startup time; t represents the current time.

[0047] The OG fan PLC performs a calculation every 500ms, substituting the current time t into the above formula to obtain the current expected speed n(t). When t-T0≥T, the expected speed equals the target speed, the buffering process ends, and the output is locked at the target speed.

[0048] Furthermore, a pre-established correlation between the fan speed and the control current of the hydraulic coupler actuator is created within the OG fan PLC. Based on field calibration data, when the fan speed is 800 r / min, the corresponding electric actuator input current is 8 mA; when the fan speed is 1200 r / min, the corresponding electric actuator input current is 16 mA. The two exhibit a linear relationship.

[0049] The OG fan PLC converts the calculated required speed n(t) into the corresponding current value using a linear interpolation formula. The conversion formula is as follows: ; In the formula, I(t) is the current value that should be output at the current moment; I low The current value corresponding to low speed is set to 8mA; I high The current value corresponding to high speed is set to 16mA; n low For the low-speed target speed, we set it to 800 r / min; n high The target speed for high speed is set to 1200 r / min.

[0050] The calculated current value is converted into a 4-20mA current signal through the PLC analog output channel and sent to the hydraulic coupler actuator.

[0051] III: If the process stage determination result in step S2 changes again during the buffering process, causing a new speed command to switch before the buffering is completed, the OG blower PLC immediately terminates the current buffering process, uses the current actual speed as the new starting speed, the current time as the new starting time, and the newly generated speed command as the target speed, and restarts the buffering control process. This design ensures that the blower speed always follows the converter process changes, while maintaining smooth speed regulation during any switching process.

[0052] In addition, the OG fan PLC collects the actual fan speed in real time during the buffering process and compares it with the expected speed for the current cycle. If the deviation between the actual speed and the expected speed continues to exceed a preset threshold and the time exceeds a set value, a speed regulation abnormality is determined, and an audible and visual alarm is issued, prompting the operator to check whether there is a jamming fault in the electric actuator or hydraulic coupling. When the buffering process ends normally, the OG fan PLC locks the speed command output to the target speed until the next command switch occurs.

[0053] Through the above steps, the OG fan PLC can achieve a smooth transition between high and low fan speeds, effectively avoiding the impact of sudden speed changes on the fan, hydraulic coupler and power grid, and ensuring the safe operation of the equipment.

[0054] Step S4 of this invention involves feedback on the action and status of the actuator. Specifically, the hydraulic coupler actuator receives a 4-20mA current signal output from the OG fan PLC, driving the scoop tube to move and change the oil filling amount in the coupler's working chamber, thereby adjusting the fan speed. Simultaneously, the OG fan PLC collects feedback signals in real time, including the actual fan speed, motor current, and actuator opening, to monitor the speed regulation effect and equipment operating status. The specific steps include: Ⅰ: The OG fan PLC sends the 4-20mA current signal calculated in step S3 to the control signal input terminal of the hydraulic coupler actuator via the analog output channel. The electric actuator has a signal conditioning circuit inside, which converts the received current signal into a position setpoint. The motor drive mechanism inside the electric actuator drives the output shaft to rotate according to the deviation between the position setpoint and the current position feedback value. This rotation, through the linkage mechanism, causes the scoop tube inside the hydraulic coupler to move axially.

[0055] The output shaft of the electric actuator is connected to the scoop tube inside the hydraulic coupler via a linkage mechanism. When the electric actuator receives a control signal, the output shaft rotates, driving the linkage mechanism to move, which in turn drives the scoop tube to move axially.

[0056] The scoop tube is a key regulating component of the hydraulic coupler, and its insertion depth into the working chamber determines the amount of oil filling the working chamber. When the scoop tube is inserted into the working chamber, the amount of oil filling decreases, and the output speed of the coupler decreases; when the scoop tube is withdrawn, the amount of oil filling increases, and the output speed of the coupler increases.

[0057] The hydraulic coupler's input end is connected to the motor shaft, and its output end is connected to the fan shaft. The motor runs at a constant speed, and the hydraulic coupler continuously adjusts its output speed by changing the amount of oil filling. When the electric actuator drives the scoop tube to change position, the amount of oil filling the coupler's working chamber changes accordingly, the coupler's output speed changes accordingly, and the fan speed changes synchronously, thus achieving smooth adjustment of the fan speed according to the expected speed calculated in step S3.

[0058] II: The OG fan PLC acquires multiple feedback signals in real time. A speed sensor is installed at the fan shaft end, and the output pulse signal is converted into an actual speed value by an intelligent instrument and then input as an analog signal to the PLC. A current transformer is installed on the three-phase power supply line of the motor. After signal conversion, the signal is connected to the analog input channel of the OG fan PLC to calculate the actual operating current value of the motor. The electric actuator has an integrated position feedback device that converts the actual position of the scoop tube into a 4-20mA analog signal, which is then connected to the OG fan PLC to determine whether the actuator accurately follows the control command.

[0059] The OG fan PLC collects the actual fan speed, motor current, and actuator opening feedback and stores them in the local data area. At the same time, it sends them to the WINCC industrial computer via Ethernet for operators to monitor in real time. The actual speed is compared with the expected speed calculated in step S3 to determine whether the speed regulation process is normal.

[0060] Through the above steps, the control commands of the present invention can be accurately transmitted to the hydraulic coupler actuator and converted into actual changes in the fan speed. At the same time, through the acquisition and monitoring of multi-dimensional feedback signals, the reliability of the speed regulation process and the safety of equipment operation are ensured.

[0061] Step S5 of the present invention is human-computer interaction and fully automatic cyclic operation. Specifically, the WINCC industrial control computer provides an operator monitoring and intervention interface to realize the automatic cyclic operation of high and low speed control of the fan, and supports flexible operation in manual mode.

[0062] The WINCC industrial control computer is located in the converter main control room and OG blower room. It is connected to the OG blower PLC via Ethernet, and receives process status, blower operating parameters and alarm information data sent by the OG blower PLC in real time, and displays them to the operators in a graphical interface.

[0063] The operation screen includes a process flow diagram area that dynamically displays the real-time status of the converter, oxygen lance, and OG blower. The oxygen lance height value, oxygen blowing valve, and nitrogen blowing valve are displayed in different colors. The blower status area displays the actual blower speed, target speed, motor current, actuator opening degree, and buffer remaining time progress bar. The operation area provides buttons to switch between automatic and manual modes, as well as high-speed, low-speed, and emergency stop buttons. The trend curve area displays the historical speed and current curves for a recent period. The alarm bar displays real-time alarm information for communication failures, speed regulation deviations, and actuator malfunctions.

[0064] Operators can select the control mode through the WINCC screen. The automatic mode is the default operating mode of this invention. In this mode, the OG blower PLC operates automatically according to the logic of steps S1 to S4, continuously adjusting the blower speed according to the changes in the converter process. Operators only monitor without intervening.

[0065] When the operator clicks the manual mode button, the system switches to manual mode. The OG fan PLC keeps the current speed unchanged. The operator can manually set the target speed by clicking the high speed button or the low speed button, or directly input the speed value for precise setting.

[0066] In manual mode, the buffer control algorithm in step S3 remains effective. After the operator manually sets a new speed, the OG blower PLC smoothly adjusts the blower speed to the set value with a 120-second buffer time, ensuring that manual operation will not cause any impact on the equipment. When the operator clicks the automatic mode button, the system switches back to automatic mode, and the blower speed is determined by the converter process signal.

[0067] The emergency stop button is prominently displayed on the control panel, and a physical button is also mounted on the control panel. In case of an emergency, when the operator presses the emergency stop button, the OG blower PLC immediately cuts off the control power to the hydraulic coupling actuator. After the electric actuator loses power, the scoop tube remains in its current position, and the blower decelerates due to inertia. At the same time, the emergency stop signal is sent to the converter PLC via Ethernet, triggering the corresponding safety interlock.

[0068] During automatic operation, the OG blower PLC continuously executes steps S1 to S4 in a loop. At the start of each smelting cycle, the system automatically completes the full speed adjustment process from low speed to high speed and back to low speed, achieving precise tracking of the blower speed and converter process. The WINCC industrial computer stores key operating data in the database, including time, process stage, blower speed, motor current, and actuator opening. It automatically generates daily energy consumption reports, calculating high-speed running time, low-speed running time, and energy savings, facilitating operators to evaluate energy-saving effects and optimize operating parameters.

[0069] Through the above steps, the present invention realizes the automated operation of the high and low speed control of the OG blower linked by the converter blowing signal. Operators can achieve intelligent control without human intervention through automatic mode, or flexibly deal with special working conditions through manual mode. At the same time, the emergency stop button and real-time alarm function ensure the safety and reliability of the system.

[0070] The second objective of this invention is to provide a converter blowing signal linkage OG blower high and low speed control system, including a signal acquisition and communication module, a process stage identification module, a buffer control module, an actuator module, and a human-machine interaction module.

[0071] The signal acquisition and communication module is used to acquire core process signals from the converter side and establish data communication between the converter PLC and the OG blower PLC. The signal acquisition and communication module includes the converter PLC located in the converter main control room, the OG blower PLC located in the OG blower room, an industrial Ethernet switch, and an optical cable connecting the two switches.

[0072] The converter PLC is equipped with an oxygen lance position acquisition unit, an oxygen blowing valve status acquisition unit, and a nitrogen blowing valve status acquisition unit. The oxygen lance position acquisition unit is connected to an absolute encoder installed on the oxygen lance lifting mechanism, which reads a 4-20mA analog signal at a fixed sampling period and converts it into an oxygen lance height value.

[0073] The oxygen blowing valve status acquisition unit is connected to the valve position feedback switch installed on the oxygen blowing valve to obtain the on / off status of the oxygen blowing valve and sets a delay filter. The nitrogen blowing valve status acquisition unit is also connected to the valve position feedback switch installed on the nitrogen blowing valve to obtain the on / off status of the nitrogen blowing valve and similarly sets a delay filter.

[0074] The converter PLC and the OG blower PLC are connected to the switch via an Ethernet communication module and exchange data using the TCP / IP protocol. This enables the periodic transmission of process signals from the converter side to the OG blower PLC, as well as the bidirectional transmission of operating status data from the OG blower PLC to the converter PLC and the WINCC industrial control computer.

[0075] The process stage identification module is located within the OG blower PLC. It identifies the current process stage of the converter based on received oxygen lance height values, oxygen valve status, and nitrogen valve status, and generates corresponding speed commands. The process stage identification module has preset thresholds for blowing position height and oxygen blowing duration.

[0076] When the oxygen lance height is below the blowing position threshold and the oxygen valve is open for a duration that reaches the preset threshold, it is determined to be the blowing stage, and a high-speed command is generated; when the oxygen lance height is below the blowing position threshold and the nitrogen valve is open, it is determined to be the slag splashing and furnace protection stage, and a low-speed command is generated; when the oxygen lance height is above the blowing position threshold or both the oxygen valve and the nitrogen valve are closed, it is determined to be the non-blowing stage, and a low-speed command is generated.

[0077] The buffer control module is located within the OG fan PLC and is used to perform smooth speed control when the speed command changes. The buffer control module has a preset buffer time of 120 seconds and a built-in ramp function generation unit. When the speed command output by the process stage identification module changes, the buffer control module records the start time of the change and the starting speed. It then calculates the expected speed in each control cycle according to the ramp function, linearly changing the expected speed from the starting speed to the target speed over 120 seconds. The expected speed calculated in each cycle is then converted into a 4-20mA analog control signal output.

[0078] The actuator module includes a hydraulic coupler actuator, a scoop tube, and a hydraulic coupler. The control signal input terminal of the hydraulic coupler actuator is connected to the analog output channel of the OG fan PLC to receive 4-20mA analog control signals. The electric actuator internally houses a motor and transmission mechanism, and its output shaft is connected to the scoop tube inside the hydraulic coupler via a linkage mechanism. Based on the received analog signal, the electric actuator drives the scoop tube to move axially, changing the oil level in the hydraulic coupler's working chamber, thereby adjusting the fan speed connected to the output terminal of the hydraulic coupler.

[0079] The human-machine interface module includes a WINCC industrial computer located in the converter main control room and the OG blower room. The WINCC industrial computer is connected to the OG blower PLC via Ethernet. The human-machine interface module provides a graphical user interface, which includes a process flow diagram display area, a blower status display area, mode switching buttons, high-speed buttons, low-speed buttons, an emergency stop button, a trend curve display area, and an alarm display area.

[0080] The human-machine interaction module supports switching between automatic and manual modes. In automatic mode, the system runs automatically according to the logic of the process stage identification module and the buffer control module. In manual mode, the operator can manually set the speed using the high-speed button or the low-speed button. The buffer control module remains active when manually set.

[0081] Through the coordinated operation of the above modules, this invention achieves precise linkage control between converter blowing signals and OG blower speed, effectively saving energy while ensuring gas recovery, and ensuring safe operation of equipment through buffer control.

[0082] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for controlling the high and low speeds of an OG blower linked to a converter blowing signal, characterized in that, Includes the following steps: S1. The converter PLC collects the oxygen lance height value output by the absolute encoder on the oxygen lance lifting mechanism, the oxygen blowing valve status output by the valve position feedback switch on the oxygen blowing valve, and the nitrogen blowing valve status output by the valve position feedback switch on the nitrogen blowing valve, and sends them to the OG blower PLC via industrial Ethernet. S2. Preset the blowing position threshold, compare the oxygen lance height value with the blowing position threshold, and generate a speed command based on the comparison result and the status of the oxygen and nitrogen valves: When the oxygen lance height is below the blowing position threshold and the oxygen valve is open, a high-speed command is generated. When the oxygen lance height is below the blowing position threshold and the nitrogen blowing valve is open, a low-speed command is generated. When the oxygen lance height value is not lower than the blowing position threshold, a low-speed command is generated; The S3 and OG fan PLC uses the speed command as the target speed and the current actual speed of the fan as the starting speed, and sets the buffer time to 120 seconds. During the buffer time, each control cycle calculates the time elapsed from the start of the buffer. Multiply the ratio of this time to the buffer time by the difference between the target speed and the starting speed, and then add the starting speed to obtain the speed that should be reached in the current cycle. Based on the linear correspondence between the expected speed and the current value, a current signal corresponding to the expected speed in the current cycle is generated and output to the hydraulic coupler actuator. S4. The electric actuator drives the scoop tube to move according to the current signal, changing the amount of oil filling the working chamber of the hydraulic coupler. The change in the amount of oil filling adjusts the speed of the fan connected to the output end of the hydraulic coupler.

2. The converter blowing signal-linked OG blower high and low speed control method according to claim 1, characterized in that: The converter PLC performs a delay filter on the collected oxygen blowing valve status. Only when the oxygen blowing valve status remains stable for more than 200ms is it confirmed as a valid status.

3. The converter blowing signal-linked OG blower high and low speed control method according to claim 1, characterized in that: The OG blower PLC performs a rationality check on the received oxygen lance height value. When the oxygen lance height value exceeds the preset normal range, the valid value of the previous cycle is used to replace the current value.

4. The converter blowing signal-linked OG blower high and low speed control method according to claim 1, characterized in that: The OG blower PLC also presets an oxygen blowing duration threshold. When the oxygen lance height is lower than the blowing position threshold and the oxygen blowing valve is open, a timer is started to accumulate the oxygen blowing valve opening duration. When the accumulated time reaches the oxygen blowing duration threshold, a high-speed command is generated. When the accumulated time does not reach the oxygen blowing duration threshold, the original speed command remains unchanged.

5. The converter blowing signal-linked OG blower high and low speed control method according to claim 1, characterized in that: The current signal is a 4-20mA current signal. The linear correspondence between the expected speed and the current value is as follows: when the expected speed is 800r / min corresponding to the low-speed command, it corresponds to an 8mA current value; when the expected speed is 1200r / min corresponding to the high-speed command, it corresponds to a 16mA current value. For the expected speed between 800r / min and 1200r / min, the current value is calculated by linear interpolation.

6. The converter blowing signal-linked OG blower high and low speed control method according to claim 1, characterized in that: The electric actuator drives the scoop tube to move axially. When the scoop tube is inserted into the working chamber of the hydraulic coupler, the amount of oil in the working chamber decreases, causing the fan speed to decrease. When the scoop tube is pulled out, the amount of oil in the working chamber increases, causing the fan speed to increase.

7. The converter blowing signal-linked OG blower high and low speed control method according to claim 1, characterized in that: The OG fan PLC collects the actual fan speed in real time during the buffering process and compares the actual fan speed with the expected speed for the current cycle. When the deviation exceeds the preset threshold, an alarm is issued.

8. The converter blowing signal-linked OG blower high and low speed control method according to claim 1, characterized in that: When the speed command of the OG fan PLC changes, if another command switch occurs during the buffering process, the current actual speed is used as the new starting speed and the current time is used as the new starting time to restart the buffer control.

9. The converter blowing signal-linked OG blower high and low speed control method according to claim 1, characterized in that: The OG fan PLC maintains the current fan speed unchanged and issues a communication fault alarm when the communication interruption exceeds a preset time.

10. A converter blowing signal-linked OG blower high / low speed control system, used to execute the converter blowing signal-linked OG blower high / low speed control method as described in any one of claims 1-9, characterized in that, It includes a signal acquisition and communication module, a process stage identification module, a buffer control module, an actuator module, and a human-machine interaction module; The signal acquisition and communication module is used to acquire oxygen lance height values, oxygen blowing valve status, and nitrogen blowing valve status, and send the acquired oxygen lance height values, oxygen blowing valve status, and nitrogen blowing valve status to the OG blower PLC via industrial Ethernet. The process stage identification module is used to generate speed commands based on the oxygen lance height value, oxygen blowing valve status, and nitrogen blowing valve status. The buffer control module is used to take the speed command as the target speed and the current actual speed of the fan as the starting speed. Within a 120-second buffer period, it calculates the expected speed for each control cycle according to the ramp function, so that the expected speed changes linearly from the starting speed to the target speed, and converts the expected speed into a current signal output. The actuator module is used to drive the scoop tube to move according to the current signal, change the oil filling amount of the hydraulic coupler working chamber, and thus adjust the fan speed; The human-machine interaction module is used to receive operating status data sent by the OG fan PLC and display it through a graphical interface, as well as to receive manual commands input by the operator and send them to the OG fan PLC.

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