A ferroalloy arc furnace electrode feed control method and system

Abstract

This invention relates to the field of metallurgical control technology, and more particularly to a method and system for electrode feed control in a ferroalloy electric arc furnace. The method includes: acquiring the operating parameters of the ferroalloy electric arc furnace; calculating the ideal arc length corresponding to each phase electrode based on the operating parameters, and determining the initial target feed amount for each phase electrode based on the difference between the ideal arc length and the current arc length; performing arc stability analysis on the current and voltage values ​​of each phase electrode, and generating electrode position compensation amounts for each phase motor to suppress arc fluctuations; performing power balance optimization calculations based on the initial target feed amount, electrode position compensation amounts, and pre-acquired three-phase power imbalance, and generating independent feed control commands to drive the action of each phase electrode; and executing each independent feed control command to adjust the feed position of the corresponding electrode. This invention can comprehensively respond to multi-dimensional operating parameters and achieve multi-objective synergistic optimization of arc stability, power balance, and electrode loss.

Description

Technical Field

[0001] This invention relates to the technical field of metallurgical control, and in particular to a method and system for controlling electrode feed in a ferroalloy electric arc furnace. Background Technology

[0002] In the ferroalloy smelting process, in order to ensure smelting efficiency, stability and economy, it is necessary to precisely control the electrode feed of the electric arc furnace. At present, the electrode automatic control strategy commonly used in the industry is mainly based on single electrical parameter feedback, such as constant current control, constant resistance control or constant power control. Existing methods monitor the current or voltage of a certain phase electrode in real time, compare it with the set value, and then drive the electrode to rise and fall to reduce deviation.

[0003] However, in actual complex smelting conditions, the electrical and physical states inside the furnace are strongly coupled and intertwined with multiple variables. Existing control methods that rely on a single or a few parameters can maintain basic operation to a certain extent, but their control dimensions are relatively singular, making it difficult to simultaneously coordinate multiple key objectives such as the physical length of the electric arc, the dynamic stability of the electric arc, the three-phase power balance, and the electrode's own losses. For example, when dealing with impedance changes caused by material melting, three-phase load asymmetry, or electrode end burnout, control logic that only targets a single electrical parameter often fails to achieve synergistic optimization in multiple dimensions such as stabilizing the electric arc, balancing the three-phase power, and electrode losses, thereby affecting the smelting process level of the electric arc furnace.

[0004] Therefore, there is an urgent need for an electrode feed control method that can comprehensively respond to multi-dimensional operating parameters and achieve multi-objective synergistic optimization of arc stability, power balance, and electrode loss. Summary of the Invention

[0005] This invention provides a method and system for controlling electrode feeding in a ferroalloy electric arc furnace, which can effectively solve the problems in the background art.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for controlling electrode feed in a ferroalloy electric arc furnace includes: The operating parameters of the ferroalloy electric arc furnace are obtained, including the current value, voltage value, arc impedance, molten pool resistance, consumption rate, and material height in the furnace of the three-phase electrodes. Based on the operating parameters, the ideal arc length corresponding to each phase electrode is calculated, and the initial feed target amount of each phase electrode is determined according to the difference between the ideal arc length and the current arc length. For the current and voltage values ​​of each phase electrode, an arc stability analysis is performed to generate the electrode position compensation amount for each phase motor to suppress arc fluctuations. Based on the initial feed target amount, the electrode position compensation amount, and the pre-acquired three-phase power imbalance, power balance optimization calculation is performed to generate independent feed control commands that drive the action of each phase electrode. Each of the aforementioned independent feed control commands is executed to adjust the feed position of the corresponding electrode.

[0007] Furthermore, the step of performing arc stability analysis and generating electrode position compensation amounts for each phase of the motor to suppress arc fluctuations includes: Calculate the fluctuation rate of arc voltage and the harmonic distortion rate of current for each phase within a preset time window; The arc voltage fluctuation rate and the current harmonic distortion rate are compared with the corresponding set thresholds respectively; Based on the comparison results, for electrodes with arc instability risk, the magnitude and direction of the electrode position compensation amount are determined, wherein the direction is to adjust the arc length in the shortening direction to stabilize the arc.

[0008] Furthermore, the step of performing power balance optimization calculations and generating independent feed control commands to drive the action of each phase electrode includes: The initial feed target amount of each phase electrode is combined with the corresponding electrode position compensation amount to obtain the comprehensive demand adjustment amount of each electrode. With the optimization objectives of minimizing the three-phase power imbalance and balancing the cumulative workload of each electrode, the independent feed control commands that satisfy the optimization objectives are calculated based on the comprehensive demand adjustment.

[0009] Furthermore, the constraints satisfied by the solution process include: The single adjustment range corresponding to the independent feed control command of each electrode shall not exceed the maximum permissible step value determined based on the thermal inertia time constant of that electrode.

[0010] Furthermore, the arc voltage fluctuation rate is the ratio of the standard deviation of the voltage sample values ​​to the average absolute value of the voltage within a preset sliding time window.

[0011] Furthermore, the current harmonic distortion rate is the ratio of the square root of the sum of the squares of the effective values ​​of each harmonic component to the effective value of the fundamental component after performing a fast Fourier transform on the instantaneous current value sequence within the same preset sliding time window.

[0012] Further, executing each of the independent feed control commands includes: Before issuing instructions, perform security pre-verification; The verified command is assigned to the corresponding electrode controller, which combines high-resolution position feedback and applies feedforward compensation and adaptive PID algorithm to generate a drive signal to control the electrode to move to the commanded position.

[0013] Furthermore, the verification includes instruction range verification, rate of change verification, and system interlock status verification.

[0014] Furthermore, the current values ​​of the three-phase electrodes are obtained by a Rogowski coil current sensor connected in series with the secondary side output terminals of each phase electrode. The voltage values ​​of the three-phase electrodes are obtained by capacitive voltage divider sensors connected in parallel between each phase electrode and the furnace body; The output signals of the current sensor and voltage sensor are connected to a synchronous data acquisition card to achieve synchronous acquisition of current and voltage signals. The arc impedance is calculated in real time based on the ratio of the instantaneous voltage value to the instantaneous current value collected synchronously at the same moment.

[0015] On the other hand, the present invention also provides an electrode feed control system for a ferroalloy electric arc furnace, comprising: The parameter acquisition module is used to acquire the operating parameters of the ferroalloy electric arc furnace, including the current value, voltage value, arc impedance, molten pool resistance, consumption rate, and material height in the furnace of the three-phase electrodes. The target calculation module is used to calculate the ideal arc length corresponding to each phase electrode based on the operating parameters, and determine the initial feed target amount of each phase electrode based on the difference between the ideal arc length and the current arc length. The stability analysis module is used to perform arc stability analysis on the current and voltage values ​​of each phase electrode and generate electrode position compensation amounts for each phase electrode to suppress arc fluctuations. The optimization decision module is used to perform power balance optimization calculations based on the initial feed target amount, the electrode position compensation amount, and the pre-acquired three-phase power imbalance, and generate independent feed control commands to drive the action of each phase electrode. The instruction execution module is used to execute each of the independent feed control instructions to adjust the feed position of the corresponding electrode.

[0016] The technical solution of this invention achieves the following technical effects: By acquiring multi-dimensional parameters such as the current value, voltage value, arc impedance, molten pool resistance, consumption rate, and material height in the furnace of the three-phase electrodes, and calculating the ideal arc length of each phase electrode based on these parameters, the initial feed target amount can be determined. This overcomes the limitation that a single parameter cannot fully reflect the coupled changes in the electrical and physical states in the furnace, enabling control commands to respond to electrical fluctuations and predict the impact of physical factors such as electrode wear or material melting, thus improving the accuracy of arc length control. Simultaneously, the position compensation amount generated by arc stability analysis is combined with power balance optimization. While suppressing instantaneous arc fluctuations, the global deviation is corrected through three-phase power imbalance, avoiding the contradiction of system imbalance caused by local optimization in existing methods, and achieving synergy between arc stability and power balance.

[0017] The initial feed target focuses on long-term process adaptation, the position compensation handles dynamic fluctuations, and the power balance optimization ensures global coordination. The sequential execution of these three not only decouples nonlinear coupling problems, but also dynamically adjusts the instructions through a feedback mechanism, enabling it to have adaptive capabilities, reducing control conflicts, and lowering electrode mechanical wear and reactive power loss caused by frequent adjustments.

[0018] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, specific embodiments of this application are given below. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a flowchart illustrating the electrode feed control method for ferroalloy electric arc furnace of the present invention. Figure 2 This is a structural block diagram of the electrode feed control system for the ferroalloy electric arc furnace of the present invention. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0023] like Figure 1 As shown, the present invention provides a method for controlling the electrode feed of a ferroalloy electric arc furnace, which specifically includes the following steps: Step S1: Obtain the operating parameters of the ferroalloy electric arc furnace, including the current value, voltage value, arc impedance, molten pool resistance, consumption rate, and material height inside the furnace of the three-phase electrodes. Step S2: Based on the operating parameters, calculate the ideal arc length corresponding to each phase electrode, and determine the initial feed target amount of each phase electrode according to the difference between the ideal arc length and the current arc length. Step S3: Perform arc stability analysis on the current and voltage values ​​of each phase electrode to generate electrode position compensation amounts for each phase motor to suppress arc fluctuations. Step S4: Based on the initial feed target amount, the electrode position compensation amount, and the pre-acquired three-phase power imbalance, perform power balance optimization calculation to generate independent feed control commands to drive the action of each phase electrode. Step S5: Execute each of the independent feed control commands to adjust the feed position of the corresponding electrode.

[0024] In this embodiment, firstly, multi-dimensional operating parameters, including current value, voltage value, arc impedance, molten pool resistance, consumption rate, and material height in the furnace, are acquired. Based on these parameters, the ideal arc length of each phase electrode is calculated to determine the initial feed target amount. Subsequently, arc stability analysis is performed on the current and voltage values ​​of each phase electrode to generate an electrode position compensation amount to suppress arc fluctuations. Finally, the initial feed target amount, electrode position compensation amount, and three-phase power imbalance are combined to perform power balance optimization calculations and generate independent feed control commands to drive the action of each phase electrode.

[0025] By acquiring multi-dimensional parameters such as the current, voltage, arc impedance, molten pool resistance, consumption rate, and material height in the furnace from the three-phase electrodes, and calculating the ideal arc length for each phase electrode based on these parameters, the initial feed target is determined. This overcomes the limitation that a single parameter cannot fully reflect the coupled changes in the electrical and physical states within the furnace, enabling control commands to respond to electrical fluctuations and predict the impact of physical factors such as electrode wear or material melting, thus improving the accuracy of arc length control. Simultaneously, the position compensation generated by arc stability analysis is combined with power balance optimization to suppress instantaneous arc fluctuations while correcting global deviations through three-phase power imbalance, avoiding the contradiction of system imbalance caused by local optimization in existing methods, and achieving synergy between arc stability and power balance.

[0026] The initial feed target focuses on long-term process adaptation, the position compensation handles dynamic fluctuations, and the power balance optimization ensures global coordination. The sequential execution of these three not only decouples nonlinear coupling problems, but also dynamically adjusts the instructions through a feedback mechanism, enabling it to have adaptive capabilities, reducing control conflicts, and lowering electrode mechanical wear and reactive power loss caused by frequent adjustments.

[0027] In a specific implementation, as one example, to meet the technical requirement of comprehensive and accurate acquisition of multi-dimensional parameters, a data acquisition system covering both electrical and physical states is constructed. This simultaneously addresses data acquisition interference caused by the special environment inside the furnace and the asynchronous timing of data acquisition for different types of parameters. A multi-unit collaborative data acquisition system is set up to achieve comprehensive acquisition of operating parameters. The specific operation is as follows: For acquiring the current and voltage values ​​of the three-phase electrodes, current acquisition is achieved by connecting Rogowski coil current sensors in series at the secondary output terminals of the three-phase electrodes. The sensors output analog signals, and the sensor installation positions are avoided in the high-temperature radiation areas of the electrodes. Voltage acquisition uses capacitive voltage divider sensors, which are connected in parallel between the three-phase electrodes and the furnace body. The sensors output analog signals, and the sensor probes are encapsulated in high-temperature resistant materials to maintain insulation from the furnace body. The output signals of the current and voltage sensors are connected to a synchronous data acquisition card to synchronously trigger the acquisition signals, ensuring that the three-phase current and voltage signals are acquired in phase synchronization.

[0028] To obtain the arc impedance, based on the instantaneous voltage and current values ​​of the three-phase electrodes acquired at the same time, the built-in impedance calculation module calculates the arc impedance in real time according to the ratio of the instantaneous voltage value to the instantaneous current value, and the calculation cycle is consistent with the sampling cycle. During the calculation process, if the instantaneous current value is lower than the electrode no-load threshold, the impedance calculation of that phase is paused and the calculation result of the previous cycle is used to avoid calculation anomalies caused by zero drift.

[0029] To obtain the molten pool resistance, detection electrodes are evenly arranged along the circumference at the bottom of the electric arc furnace body. The axis of the detection electrodes forms a preset angle with the central axis of the furnace body, and the top of the electrodes is flush with the surface of the refractory layer at the bottom of the furnace. An insulating structure is used to isolate the detection electrodes from the metal shell of the furnace body. The resistance signal output by the detection electrodes is transmitted to the differential signal conditioning module via a shielded cable, and the conditioned signal is connected to the data acquisition card. Based on the resistance values ​​between each pair of detection electrodes, the molten pool resistance is calculated using a weighted average method. The measurement deviation caused by the unevenness of the local molten pool state is eliminated by fusing data from multiple measurement points.

[0030] To obtain the electrode consumption rate, a laser displacement sensor is installed on the fixed support of each phase electrode. The sensor emits light along the electrode axis and is installed at a preset distance from the electrode surface, avoiding the electrode lifting path. During initial electrode installation, the initial electrode length and the initial position measured by the sensor are recorded, along with the electrode connector length. During smelting, the current electrode position measured by the sensor is collected in real time, and the cumulative smelting time is recorded. The electrode consumption rate for that phase is calculated by subtracting the electrode connector length from the difference between the initial and current positions and then dividing the result by the cumulative smelting time. When the electrode is replaced, the initial length and initial position of the new electrode are recorded again, and the cumulative smelting time is reset to ensure the continuity of the consumption rate calculation.

[0031] To obtain the material height inside the furnace, a pulsed laser rangefinder sensor is used, installed at a pre-reserved detection hole in the center of the electric arc furnace cover. The detection direction is perpendicular to the molten pool surface, and the detection hole is equipped with a high-temperature resistant transparent window. Thermocouples are installed at preset positions on the side wall of the furnace to collect the real-time temperature inside the furnace. The temperature signal is transmitted to a temperature compensation module, which has a built-in table of the correspondence between temperature and laser propagation speed. The laser propagation speed is called according to the correspondence. The material height is calculated by subtracting half of the product of the laser round-trip time and the laser propagation speed from the fixed distance from the sensor installation reference plane to the furnace bottom. Temperature compensation eliminates the influence of high temperature on laser propagation speed, ensuring measurement accuracy.

[0032] In this embodiment, multi-dimensional parameter acquisition covers all input requirements for subsequent ideal arc length calculation, arc stability analysis, and power balance optimization, eliminating the need for additional acquisition and preventing control logic gaps due to missing parameters. The synchronous triggering mechanism eliminates timing deviations in the acquisition of different parameters, ensuring the accuracy of parameters such as arc impedance and molten pool resistance that rely on multi-parameter calculations. The special design for the unique furnace environment reduces the impact of environmental factors on acquisition accuracy and avoids control deviations caused by data distortion.

[0033] In a specific implementation, as one example, based on the multi-dimensional operating parameters obtained in step S1, the dynamic ideal arc length of each phase electrode is determined through a calculation model, and the initial feed target amount is generated accordingly. Specifically, the step-by-step calculation process of the ideal arc length is as follows: For the i-th phase electrode (i=a,b,c), its ideal arc length L ideal,i The calculation model consists of a linear superposition of three basic electrical length components, a molten pool interaction correction component, and a material height compensation component. The formula for calculating the ideal arc length is as follows: L ideal,i =L elec,i +ΔL bath,i +ΔL stock,i ; L elec,i The formula for calculating the basic electrical length component is as follows: L elec,i =K1×(U i / I i ); Among them, U i I represents the real-time voltage to ground of the i-th phase electrode, in volts; i This represents the real-time current of the i-th phase electrode, in amperes; (U i / I i ) represents the apparent impedance of the current arc circuit, in ohms; K1 represents the length impedance proportionality coefficient, in meters per ohm, which is determined by statistically analyzing the stable arc length and corresponding impedance in historical process data, converting the impedance dimension into the length dimension; the basic electrical length component reflects the approximate physical spatial scale required to maintain arc combustion under a given current and voltage.

[0034] ΔL bath,i The melt pool interaction correction component is represented by the following formula: ΔL bath,i =K2×(R m -R nom ); Among them, R m R represents the real-time equivalent resistance of the molten pool obtained in step S1, in ohms. nom K1 represents the nominal molten pool resistance at the current smelting stage, measured in ohms. This value is set based on the typical molten pool state of a specific ferroalloy at the corresponding smelting stage. K2 represents the molten pool resistance correction factor, measured in meters per ohm. This factor determines the sensitivity of adjusting the ideal arc length when the molten pool resistance deviates from the nominal value. The influence of the molten pool state on the ideal arc length is introduced through the molten pool interaction correction component. Changes in molten pool resistance characterize changes in molten pool temperature, composition, or size, directly affecting the arc energy transfer efficiency. When the molten pool resistance is higher than the nominal value, this component is positive, suggesting a moderate increase in the ideal arc length to adjust the energy injection mode; conversely, it is negative. This correction allows the ideal arc length to adapt to changes in the physicochemical state of the molten pool, aiming to optimize the energy transfer process.

[0035] ΔL stock,iThe formula for calculating the material height compensation component is as follows: ΔL stock,i =K3×(H nom -H m ); Among them, H m H represents the real-time material height inside the furnace obtained in step S1, in meters. nom The desired material height at the current smelting stage is expressed in meters; K3 represents the material height compensation coefficient, a dimensionless constant that determines the adjustment ratio of arc length requirements to changes in material height; the material height compensation component incorporates the influence of furnace charge geometry on the ideal arc length; the material height determines the degree of arc exposure and thermal radiation environment; when the actual material height is lower than the desired value, the value in parentheses is positive, indicating a positive component, suggesting an increase in the ideal arc length to avoid excessive arc concentration and localized overheating; conversely, it is negative; this compensation allows the ideal arc length to adapt to changes in the spatial distribution of materials within the furnace, aiming to ensure uniform melting and avoid damage to the furnace lining.

[0036] Furthermore, after calculating the ideal arc length of the i-th phase electrode, the current physical arc length L of the electrode is obtained through an electrode position encoder. current,i The initial feed target amount ΔZ target,i The calculation formula is as follows: ΔZ target,i =L ideal,i -L current,i ; Initial feed target ΔZ target,i The unit is meters, and its value and symbol are used to represent the basic displacement required for the phase electrode to be moved to adjust the current actual arc length to the ideal state under the current working conditions as determined by this calculation model. Positive values ​​correspond to descent commands, and negative values ​​correspond to elution commands.

[0037] In this embodiment, the fixed electrical setpoint in traditional control is transformed into a physical length target that is dynamically optimized according to real-time operating conditions. Key operating parameters such as electrical characteristics, molten pool state, and material geometry are designed into the same calculation framework, so that the obtained ideal arc length simultaneously reflects the current requirements of loop impedance, energy transfer efficiency, and furnace space constraints. The initial feed target determined in this way can provide a reasonable adjustment benchmark based on multi-dimensional process conditions, so that stability compensation and multi-objective power balance optimization can be initiated and converged in a direction closer to the actual process optimum, enhancing the consistency of multi-objective collaborative control under complex operating conditions.

[0038] In a specific implementation, as one example, in step S3, based on the real-time acquired electrical signals, an electrode position compensation quantity for actively suppressing arc dynamic fluctuations is generated through quantitative calculation and risk assessment of stability characteristic quantities. The core of existing electrode control logic is to maintain the steady-state values ​​of electrical parameters such as current, voltage, or power. However, arc instability in actual production, such as arc drift and surge, is essentially a deterioration of the dynamic quality of electrical parameters, manifested as severe fluctuations in instantaneous values ​​and waveform distortion. Existing feedback control based on steady-state value deviation has an inherent lag in response to such dynamic problems, usually only starting to act after the arc has become significantly unstable. Based on the analysis of the arc dynamic combustion process, a monitoring and adjustment mechanism specifically targeting the dynamic quality of electrical signals is established, independent of steady-state setpoint tracking. The core concept of this mechanism is to define an electrical characteristic quantity that can characterize the dynamic stability of the arc in real time and with high sensitivity. When this electrical characteristic quantity indicates a risk of instability, a preventative, directionally determined electrode position fine-tuning command is immediately generated based on the physical characteristics of the arc, thereby intervening before the arc state deteriorates further. The specific implementation is as follows: Step S31: To quantify the dynamic behavior of the electric arc, define and calculate the arc voltage fluctuation rate and current harmonic distortion rate. The arc voltage fluctuation rate is used to assess the severity of arc voltage fluctuations over a short period. Specifically, the system continuously acquires instantaneous electrode voltage values ​​at a sampling frequency of at least 10 kHz. Within a preset sliding time window, such as 100 milliseconds, the standard deviation of all voltage samples within that window is calculated. Subsequently, the ratio of this standard deviation to the average absolute voltage value within the same window is calculated, and this ratio is defined as the arc voltage fluctuation rate. This calculation eliminates the influence of the absolute voltage value on the evaluation results, allowing the fluctuation rate to purely reflect the relative instability of the voltage. The harmonic distortion rate of current is used to assess the degree of distortion of the current waveform and reflects the regularity of arc combustion. The specific calculation process is as follows: perform spectral analysis on the instantaneous current value sequence within the same time window that is acquired synchronously with the voltage; obtain the effective value of the fundamental component and the effective value of each harmonic component of the current signal through fast Fourier transform; the current harmonic distortion rate is calculated as the ratio of the square root of the sum of the squares of the effective values ​​of each harmonic component to the effective value of the fundamental component; the higher this ratio, the greater the deviation of the current waveform from the standard sine wave, which usually corresponds to a more unstable arc combustion state.

[0039] Step S32: To achieve automatic judgment, a judgment threshold is preset for each characteristic quantity in step S31, namely the voltage fluctuation rate threshold and the current harmonic distortion rate threshold. Both are determined by analyzing historical data accumulated during the long-term stable operation of the electric arc furnace and are used to represent the safe upper limit of the characteristic quantity under normal operating conditions. In each calculation cycle, the voltage fluctuation rate and current harmonic distortion rate calculated in real time are compared with their corresponding preset thresholds. The judgment logic is: if the voltage fluctuation rate of the current calculation cycle exceeds its threshold, or the current harmonic distortion rate exceeds its threshold, or both exceed it at the same time, it is determined that the phase electrode has an arc instability risk at the current moment. This risk indicator will trigger the generation of subsequent compensation instructions.

[0040] Step S33: For electrodes that are determined to have an instability risk, generate the corresponding electrode position compensation amount according to the predetermined rules; the compensation direction is uniformly determined to drive the electrode to move downward to shorten the physical length of the arc. This decision is based on the physical characteristics of the arc: in most working conditions that lead to instability, appropriately shortening the arc length helps to reduce the arc equivalent impedance, enhance the rigidity of the arc column and its resistance to disturbances. The magnitude of the compensation is positively correlated with the degree to which the stability characteristic exceeds the threshold. The specific calculation rules are as follows: when only the voltage fluctuation rate exceeds the limit, the compensation is proportional to the portion of the fluctuation rate exceeding the threshold; when only the current harmonic distortion rate exceeds the limit, the compensation is proportional to the portion of the harmonic distortion rate exceeding the threshold; when both characteristic values ​​exceed the limit simultaneously, the compensation is the weighted sum of the above two proportional calculation results. The proportional coefficient and weighting coefficient are experimentally tuned according to the response characteristics of the specific furnace type. Their function is to convert the degree of electrical quantity exceeding the limit into a practically meaningful electrode displacement adjustment amount. The final compensation amount is a positive value, representing the recommended distance the electrode should be lowered.

[0041] In this embodiment, by performing real-time online quantitative diagnosis of the fluctuations and waveform distortions of electrical signals, and based on the diagnostic results and a fixed arc stabilization physical strategy, a preventative adjustment command is proactively generated. The generation of this command does not depend on the slow accumulation of steady-state deviations, but is based on the rapid identification of early electrical characteristics of arc instability. It can apply a directional correction action before the arc oscillation intensifies or arc breakage occurs. This compensation amount is combined with the initial target amount based on process optimization provided in step S2, so that the control command simultaneously takes into account both long-term process objectives and instantaneous process stability.

[0042] In a specific implementation, as one example, in step S4, based on the initial feed target amount, electrode position compensation amount, and system power state, multi-objective optimization calculation is used to generate the final coordinated control command that drives the action of each electrode. This embodiment provides a coordinated decision-making method based on optimization theory, and the specific implementation includes the following steps: Step S41, define the decision variable of this control cycle as the final independent feed control command of the three-phase electrodes, denoted as the command vector, including the command displacement corresponding to the three-phase electrodes a, b, and c respectively; the input parameters include: the initial feed target amount of each phase electrode output by step S2; the position compensation amount of each phase electrode output by step S3; the instantaneous value of the three-phase active power calculated based on the real-time collected voltage and current values, used to evaluate the current and predict the future power imbalance; the current actual physical position of each electrode; and the historical accumulated operating indicators of each electrode related to thermomechanical load.

[0043] Step S42: Calculate the corresponding comprehensive demand adjustment for each phase electrode. This adjustment is a weighted fusion of the initial process target and dynamic stability compensation. The calculation formula is: Comprehensive demand adjustment = (Process target weight coefficient × Initial feed target amount) + (Stability compensation weight coefficient × Electrode position compensation amount). The stability compensation weight coefficient can be dynamically adjusted according to the arc instability risk level assessed in Step 3: when the risk level is high, the coefficient is increased to prioritize stability; when the risk level is low, the coefficient is decreased to focus more on achieving the process target. The comprehensive demand adjustment represents the expected adjustment amount of each electrode under the condition of ignoring the coupling effect between electrodes and system constraints.

[0044] Step S43: Using the instruction vector as the optimization variable, construct a mathematical model that includes two optimization objectives and a set of hard constraints; The first optimization objective is to minimize the three-phase active power imbalance. This objective aims to improve the power quality on the grid side. Mathematically, it is expressed as minimizing the maximum relative deviation of the three-phase active power. To achieve this objective, a response model describing the relationship between electrode position changes and active power changes needs to be established. This model can be obtained through offline simulation, historical data fitting, or online parameter identification methods. Using this model, the expected value of the three-phase active power can be predicted after executing a set of candidate commands. The objective function is to calculate and minimize the maximum relative deviation of these three predicted power values ​​relative to their average value. The second optimization objective is to balance the cumulative workload of each electrode. This objective aims to extend the overall lifespan of the electrode group and achieve equipment health management. A cumulative load index is maintained for each electrode, which takes into account factors such as historical travel, arc current, and working time. The second optimization objective requires that after the execution of a new control command, the updated predicted cumulative load index of each electrode should be as balanced as possible. Mathematically, this can be expressed as minimizing the variance or range of the above predicted load values. It also encourages avoiding overuse of a certain phase electrode during long-term operation. The hard constraints include single adjustment amplitude constraints and demand tracking deviation constraints. Among them, the single adjustment amplitude constraint means that the absolute value of the single displacement command change of each electrode must not exceed a preset maximum allowable step value. This maximum value is determined based on the thermal inertia time constant of the electrode and its lifting mechanism. The physical basis is that excessively fast electrode movement will cause the electrode surface and slag line area to suffer severe thermal shock, which may induce cracks or spalling on the electrode surface. The constraint value is inversely proportional to the thermal inertia time constant of the electrode system. The demand tracking deviation constraint means that the final generated instructions should not completely ignore the local integrated requirements of each electrode. To this end, an allowable tracking deviation tolerance is set, which constrains the deviation between the instruction value of each electrode in the instruction vector and the target position obtained by adding the integrated demand adjustment to its current actual position. This ensures that the optimization solution is always searched around the actual process and stable requirements.

[0045] Step S44: The above mathematical model is converted into a single-objective optimization problem using a scalarization method. For example, the linear weighted method assigns weights to the two sub-objective functions of minimizing power imbalance and balancing electrode load, and sums them to form a total objective function. The weight allocation reflects the emphasis on different performance objectives at a specific production stage. Subsequently, a numerical optimization algorithm, such as a sequential quadratic programming algorithm or a particle swarm optimization algorithm, is used to search for the instruction vector that minimizes the total objective function value in the solution space that satisfies all constraints. The instruction vector obtained through numerical calculation is the independent feed control command that drives the a, b, and c phase electrodes to move in the current control cycle.

[0046] In this embodiment, by dynamically weighting and fusing the initial feed target and electrode position compensation, stability or process objectives can be prioritized based on the arc instability risk level, ensuring that the overall demand adjustment matches actual needs. Minimizing three-phase active power imbalance and balancing electrode cumulative workload are the dual optimization objectives. Combining the power response model and cumulative load index, the power quality on the grid side is improved, and overuse of a single electrode is avoided to extend the overall lifespan of the electrode group. Setting single-adjustment amplitude constraints based on electrode thermal inertia and demand tracking deviation constraints prevents severe thermal shock to the electrodes and ensures that commands do not deviate from core process and stability requirements. Through scalar conversion and numerical optimization algorithms, the resulting independent feed control command achieves multi-objective collaborative optimization while satisfying all constraints.

[0047] In a specific implementation, as one example, step S5 is implemented as follows: Before the instruction is sent to the execution driver, a safety pre-verification is first performed; the verification includes instruction range verification, rate of change verification, and system interlock status verification; the instruction range verification is used to confirm that the displacement value of each electrode instruction does not exceed the absolute physical limit of the mechanical stroke of the electrode; the rate of change verification is used to confirm that the rate of change of each electrode instruction relative to its current position does not exceed the safety rate of change threshold set based on the mechanical structural strength of the equipment and the maximum speed of the drive motor; the system interlock status verification is used to confirm that the key interlock conditions such as no emergency stop signal for the electric arc furnace body and the electrode lifting system, normal hydraulic system pressure, and normal cooling system operation are all in the "allowed" state; only when all safety verifications pass are the instruction allowed to be transmitted to the next level; if any verification fails, the instruction is intercepted, the system triggers an alarm and maintains the electrode in the current position or enters the preset safety holding mode.

[0048] The command vector that passes the safety verification is assigned to the corresponding electrode controller, such as a servo drive or a hydraulic proportional valve controller; the controller generates the corresponding drive signal based on the received target displacement command and its internal high-resolution position feedback.

[0049] Specifically, for electric actuators such as servo motors, the drive signal is a pulse sequence or analog voltage signal, controlling the motor speed and direction. For hydraulic actuators, the drive signal is the current signal of the proportional valve, controlling the hydraulic oil flow and direction.

[0050] During signal generation, the controller applies feedforward compensation and adaptive PID algorithm. Feedforward compensation is based on the known dynamic model of the electrode and load, and the compensation amount is given in advance to overcome system inertia. The adaptive PID parameters can be fine-tuned according to the current actual load rate of the electrode to suppress the tracking characteristic fluctuation caused by load changes.

[0051] In this embodiment, before the command is executed, a multi-dimensional safety pre-verification is performed on the command range, rate of change, and system interlock status. This can intercept risky commands that exceed the mechanical stroke, violate equipment strength limits, or fail to meet system interlock conditions, thus avoiding faults such as electrode collisions and actuator damage. After the command is assigned to the controller, a drive signal is generated by combining high-resolution position feedback to adapt to the needs of different electric and hydraulic actuators. The controller applies feedforward compensation and adaptive PID algorithms. The former overcomes system inertia in advance based on the dynamic model, while the latter fine-tunes parameters according to the load rate to suppress tracking fluctuations, ensuring that the electrode displacement accurately tracks the target command while ensuring equipment safety during the execution process.

[0052] Based on the same inventive concept as the electrode feed control method for a ferroalloy electric arc furnace described in the foregoing embodiments, this invention also provides an electrode feed control system for a ferroalloy electric arc furnace, such as... Figure 2 As shown, the system includes: The parameter acquisition module is used to acquire the operating parameters of the ferroalloy electric arc furnace, including the current value, voltage value, arc impedance, molten pool resistance, consumption rate, and material height in the furnace of the three-phase electrodes. The target calculation module is used to calculate the ideal arc length corresponding to each phase electrode based on the operating parameters, and determine the initial feed target amount of each phase electrode based on the difference between the ideal arc length and the current arc length. The stability analysis module is used to perform arc stability analysis on the current and voltage values ​​of each phase electrode and generate electrode position compensation amounts for each phase electrode to suppress arc fluctuations. The optimization decision module is used to perform power balance optimization calculations based on the initial feed target amount, the electrode position compensation amount, and the pre-acquired three-phase power imbalance, and generate independent feed control commands to drive the action of each phase electrode. The instruction execution module is used to execute each of the independent feed control instructions to adjust the feed position of the corresponding electrode.

[0053] The system described above in this invention can effectively realize the electrode feeding control method for ferroalloy electric arc furnaces, and the technical effects it can achieve are as described in the above embodiments, which will not be repeated here.

[0054] Although this application has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made thereto without departing from the spirit and scope of this application. Accordingly, this specification and drawings are merely exemplary illustrations of the application as defined herein, and are to be considered as covering any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from its scope. Thus, if such modifications and modifications fall within the scope of this application and its equivalents, this application intends to include such modifications and modifications.

Claims

1. A method for controlling electrode feed in a ferroalloy electric arc furnace, characterized in that, include: The operating parameters of the ferroalloy electric arc furnace are obtained, including the current value, voltage value, arc impedance, molten pool resistance, consumption rate, and material height in the furnace of the three-phase electrodes. Based on the operating parameters, the ideal arc length corresponding to each phase electrode is calculated, and the initial feed target amount of each phase electrode is determined according to the difference between the ideal arc length and the current arc length. For the current and voltage values ​​of each phase electrode, an arc stability analysis is performed to generate the electrode position compensation amount for each phase motor to suppress arc fluctuations. Based on the initial feed target amount, the electrode position compensation amount, and the pre-acquired three-phase power imbalance, power balance optimization calculation is performed to generate independent feed control commands that drive the action of each phase electrode. Each of the aforementioned independent feed control commands is executed to adjust the feed position of the corresponding electrode.

2. The electrode feed control method for ferroalloy electric arc furnace according to claim 1, characterized in that, The process of performing arc stability analysis and generating electrode position compensation amounts for each phase of the motor to suppress arc fluctuations includes: Calculate the fluctuation rate of arc voltage and the harmonic distortion rate of current for each phase within a preset time window; The arc voltage fluctuation rate and the current harmonic distortion rate are compared with the corresponding set thresholds respectively; Based on the comparison results, for electrodes with arc instability risk, the magnitude and direction of the electrode position compensation amount are determined, wherein the direction is to adjust the arc length in the shortening direction to stabilize the arc.

3. The electrode feed control method for ferroalloy electric arc furnace according to claim 2, characterized in that, The process of performing power balance optimization calculations and generating independent feed control commands to drive the action of each phase electrode includes: The initial feed target amount of each phase electrode is combined with the corresponding electrode position compensation amount to obtain the comprehensive demand adjustment amount of each electrode. With the optimization objectives of minimizing the three-phase power imbalance and balancing the cumulative workload of each electrode, the independent feed control commands that satisfy the optimization objectives are calculated based on the comprehensive demand adjustment.

4. The electrode feed control method for ferroalloy electric arc furnace according to claim 3, characterized in that, The constraints that the solution process must satisfy include: The single adjustment range corresponding to the independent feed control command of each electrode shall not exceed the maximum permissible step value determined based on the thermal inertia time constant of that electrode.

5. The electrode feed control method for ferroalloy electric arc furnace according to claim 2, characterized in that, The arc voltage fluctuation rate is the ratio of the standard deviation of the voltage sample values ​​to the average absolute value of the voltage within a preset sliding time window.

6. The electrode feed control method for a ferroalloy electric arc furnace according to claim 5, characterized in that, The current harmonic distortion rate is the ratio of the square root of the sum of the squares of the effective values ​​of each harmonic component to the effective value of the fundamental component after performing a fast Fourier transform on the instantaneous current value sequence within the same preset sliding time window.

7. The electrode feed control method for ferroalloy electric arc furnace according to claim 1, characterized in that, The execution of each of the independent feed control commands includes: Before issuing instructions, perform security pre-verification; The verified command is assigned to the corresponding electrode controller, which combines high-resolution position feedback and applies feedforward compensation and adaptive PID algorithm to generate a drive signal to control the electrode to move to the commanded position.

8. The electrode feed control method for a ferroalloy electric arc furnace according to claim 7, characterized in that, The verification includes instruction range verification, rate of change verification, and system interlock status verification.

9. The electrode feed control method for a ferroalloy electric arc furnace according to claim 1, characterized in that, The current values ​​of the three-phase electrodes are obtained by Rogowski coil current sensors connected in series to the secondary side output terminals of each phase electrode. The voltage values ​​of the three-phase electrodes are obtained by capacitive voltage divider sensors connected in parallel between each phase electrode and the furnace body; The output signals of the current sensor and voltage sensor are connected to a synchronous data acquisition card to achieve synchronous acquisition of current and voltage signals. The arc impedance is calculated in real time based on the ratio of the instantaneous voltage value to the instantaneous current value collected synchronously at the same moment.

10. A ferroalloy electric arc furnace electrode feed control system, characterized in that, include: The parameter acquisition module is used to acquire the operating parameters of the ferroalloy electric arc furnace, including the current value, voltage value, arc impedance, molten pool resistance, consumption rate, and material height in the furnace of the three-phase electrodes. The target calculation module is used to calculate the ideal arc length corresponding to each phase electrode based on the operating parameters, and determine the initial feed target amount of each phase electrode based on the difference between the ideal arc length and the current arc length. The stability analysis module is used to perform arc stability analysis on the current and voltage values ​​of each phase electrode and generate electrode position compensation amounts for each phase electrode to suppress arc fluctuations. The optimization decision module is used to perform power balance optimization calculations based on the initial feed target amount, the electrode position compensation amount, and the pre-acquired three-phase power imbalance, and generate independent feed control commands to drive the action of each phase electrode. The instruction execution module is used to execute each of the independent feed control instructions to adjust the feed position of the corresponding electrode.

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