CN-122018601-A - Temperature feedback control method and system for smelting stage of electric arc furnace flat molten pool

CN122018601ACN 122018601 ACN122018601 ACN 122018601ACN-122018601-A

Abstract

The invention relates to the technical field of data processing, in particular to a temperature feedback control method and a system for a smelting stage of a flat molten pool of an electric arc furnace. The method comprises the steps of periodically extracting arc force indexes and vibration response indexes of all channels according to current signals and vibration signals of all channels, storing the two pairs of arc force indexes into a historical data queue and updating the historical data queue, judging whether the discrete degree of the arc force indexes in the queue meets the validity condition according to all the channels, if so, fitting to obtain vibration force transmission ratios according to all the pairs of data in the queue, determining the reliability of vibration signals according to the arc force indexes and the vibration response indexes in the queue, determining real-time electric energy thermal efficiency according to preset efficiency parameters, transmission ratios and reliability, correcting real-time electric power based on the real-time electric energy thermal efficiency, determining the net heating power of molten steel by combining chemical reaction thermal power and heat loss power, accumulating and integrating based on the net heating power of molten steel, and determining the predicted temperature of molten steel, so that the accuracy of predicted temperature is improved.

Inventors

ZHANG LILIANG
TIAN CHANGYONG

Assignees

湖南泰安硅业有限公司

Dates

Publication Date: 20260512
Application Date: 20260203

Claims (10)

1. A method for controlling temperature feedback in a smelting stage of a flat molten pool of an electric arc furnace, which is characterized by comprising the following steps: Obtaining a measured temperature of molten steel in response to the smelting entering a flat melting pool stage; According to the current signals and vibration signals of all channels, the arc force amplitude and vibration response amplitude of all channels are periodically extracted, and the arc force index and vibration response index are respectively standardized and then obtained; judging whether the discrete degree of the electric arc force index in the queue meets the validity condition or not according to each channel, if so, fitting to obtain a vibration force transmission ratio according to all data pairs in the queue, determining the reliability of a vibration signal according to the correlation between the electric arc force index in the queue and a vibration response index, and determining the real-time electric energy thermal efficiency of the channel according to preset efficiency parameters, transmission ratio and reliability; Correcting the real-time electric power based on the real-time electric energy thermal efficiency, and combining the preset chemical reaction thermal power and the preset heat loss power to determine the net heating power of the molten steel; and controlling a smelting end point according to the predicted temperature, and executing corresponding optimized smelting operation according to the real-time electric energy thermal efficiency.
2. The method for controlling temperature feedback in the smelting stage of a flat molten pool of an electric arc furnace according to claim 1, wherein the current signal comprises current instantaneous values of electrode channels of each phase acquired through a current transformer, and the furnace wall vibration signal comprises furnace wall vibration acceleration instantaneous values of each region acquired through a vibration acceleration sensor installed on the outer wall of a furnace shell of the electric arc furnace and corresponding to the physical position of each phase electrode; the arc force index and vibration response index obtaining process comprises the following steps: The method comprises the steps of obtaining a current signal, carrying out square operation on current instantaneous values at all collecting moments in the current signal to obtain current square values, and generating an arc force equivalent signal proportional to the Lorentz force of an arc according to the current square values at all collecting moments in time sequence; For each electrode channel, acquiring a current square value sequence and a vibration acceleration instantaneous value sequence in each period, and acquiring a preset arc force reference amplitude and a preset vibration response reference amplitude; Performing fast Fourier transform on the current square value sequence in each period to obtain a first frequency spectrum; Reading complex numbers corresponding to the same target frequency from a second frequency spectrum, and taking the module length of the complex numbers as vibration response amplitude; Dividing the amplitude of the arc force by a preset arc force reference amplitude to obtain an arc force index of each periodic channel, and dividing the vibration response amplitude by a preset vibration response reference amplitude to obtain a vibration response index of each periodic channel.
3. The method for controlling temperature feedback in a molten pool smelting stage of an electric arc furnace according to claim 1, wherein the history data queue is maintained by a first-in first-out queue data structure for storing an arc force index and a vibration response index in each electrode channel period, and the queue has a preset maximum length; the method for storing the two component data pairs in each channel historical data queue according to time sequence and updating comprises the following steps: combining an arc force index and a vibration response index of a channel obtained in a current period into a group of new data pairs for each electrode channel, adding the new data pairs to the head of a historical data queue maintained for the channel; And removing the oldest data pair positioned at the tail of the queue if the current length of the added queue exceeds the preset maximum length, wherein if the number of the data pairs in the queue maintained by the channel does not reach the preset maximum length, a preset safety efficiency value is adopted for the channel.
4. A method for controlling temperature feedback in a molten bath smelting stage of an electric arc furnace according to claim 3, wherein the determining whether the degree of dispersion of the electric arc force index in the queue satisfies the validity condition comprises: for each electrode channel, calculating standard deviation of all arc force indexes in a queue maintained by the current period channel as a fluctuation index; If the fluctuation index is smaller than a preset fluctuation threshold, judging that all data pairs in a queue of a channel in the current period are invalid, and skipping the subsequent transmission ratio and reliability calculation, and adopting a preset safety efficiency value as the real-time electric energy thermal efficiency of the channel in the current period for the channel.
5. The method for controlling temperature feedback in a molten bath smelting stage of an electric arc furnace according to claim 4, wherein the process for obtaining the vibration force transmission ratio comprises the steps of: for each electrode channel, carrying out linear regression through a least square method based on all electric arc force indexes and vibration response index data pairs in a queue maintained by the current period channel to obtain regression slope of the vibration response index relative to the electric arc force index; The regression slope is taken as the vibration force transmission ratio of the channel in the current period.
6. The method for temperature feedback control in the melting stage of a flat bath of an electric arc furnace according to claim 4, wherein the vibration signal reliability determining process comprises: for each electrode channel, respectively generating an arc force index sequence and a vibration response index sequence in the current period channel according to a time sequence based on all data pairs in a queue maintained in the current period channel; Calculating a pearson correlation coefficient between the electric arc force index sequence and the vibration response index sequence as a correlation coefficient; and taking the square value of the correlation coefficient as the reliability of the vibration signal of the channel in the current period.
7. The method according to claim 1, wherein the preset efficiency parameters comprise a preset efficiency reference value and a preset maximum efficiency loss value; The real-time electric energy thermal efficiency determining process includes: acquiring a credibility threshold; For each electrode channel, adopting a preset S-shaped function to map the reliability of the vibration signal in the current period channel to a reliability weight between 0 and 1, wherein if the reliability of the vibration signal is far lower than a reliability threshold value, the mapped reliability weight approaches 0, and if the reliability of the vibration signal is far higher than the reliability threshold value, the mapped reliability weight approaches 1; Calculating the product of the vibration force transmission ratio of the channel in the current period and a preset maximum efficiency loss value as an efficiency loss amount; and subtracting the product of the credibility weight and the efficiency loss from a preset efficiency reference value to obtain the real-time electric energy thermal efficiency of the current period channel.
8. The method for temperature feedback control in the melting stage of a flat bath of an electric arc furnace according to claim 7, wherein the process for determining the net heating power of the molten steel comprises the steps of: Acquiring the real-time electric power of each electrode channel, and acquiring the preset chemical reaction heat power and the preset heat loss power; multiplying the real-time electric power of each electrode channel by the corresponding real-time electric energy thermal efficiency to obtain the effective electric power of each channel; Summing the effective electric power of all channels to obtain total effective electric power; subtracting the preset heat loss power from the sum of the total effective electric power and the preset chemical reaction heat power to obtain the net heating power of the molten steel.
9. The method for temperature feedback control in the melting stage of a flat melting tank of an electric arc furnace according to claim 1, wherein the molten steel prediction temperature determining process comprises: maintaining a preset temperature prediction integrator, wherein the state of the preset temperature prediction integrator comprises an initial temperature value and an accumulated heat energy value; The temperature prediction integrator takes the preset molten steel mass and the preset specific heat capacity as parameters, continuously accumulating the product of the net heating power of the molten steel and the time to update an accumulated heat energy value, dividing the accumulated heat energy value by the product of the preset molten steel estimated mass and the preset molten steel specific heat capacity to obtain a temperature rise value from an initial moment, and adding the temperature rise value and the initial temperature value to obtain the predicted molten steel temperature at the current moment; the initial temperature value is set as the measured temperature of the molten steel obtained for the first time at the starting time, and is updated as a new measured temperature value every time a new measured temperature of the molten steel is obtained subsequently, and meanwhile, the accumulated heat energy value is reset to zero.
10. A temperature feedback control system for a flat bath smelting stage of an electric arc furnace, characterized in that the system comprises a memory, a processor and a computer program stored in the memory and running on the processor, characterized in that the processor implements the steps of the method according to any one of claims 1-9 when executing the computer program.

Description

Temperature feedback control method and system for smelting stage of electric arc furnace flat molten pool Technical Field The invention relates to the technical field of data processing, in particular to a temperature feedback control method and a system for a smelting stage of a flat molten pool of an electric arc furnace. Background In the electric arc furnace steelmaking process, the level bath smelting stage is a key link for determining the temperature and quality of final molten steel. Scrap steel in the furnace is basically melted in the flat bath stage to form a liquid bath, and foam slag submerged arc operation is generally adopted to improve the heat efficiency and protect the furnace lining. The accurate control of the temperature of molten steel is a core target, and steel needs to be tapped in time when the target temperature is reached, so that energy waste or low-temperature steel accidents are avoided. At present, the industry mainly relies on an energy integration model (also called a heat balance model) to estimate the temperature of molten steel, the model usually assumes the heat conversion efficiency of electric energy to be constant, however, the model has the following defects that firstly, the model cannot sense the real-time heat efficiency dynamic drift caused by the severe change of foam slag state, the model still calculates according to high efficiency in the low-efficiency period of foam slag collapse (bare arc), the false temperature rise is extremely easy to cause the virtual high of the predicted temperature and the steel judgment is seriously misled, secondly, the vibration signal is tried to be introduced to monitor the slag condition, but the effective vibration caused by the change of arc force and the ineffective vibration caused by mechanical noise such as waste steel collapse, bath boiling and the like cannot be effectively distinguished, so that the control system frequently acts by mistake under the interference of strong noise, and the temperature prediction precision and the process control reliability are severely restricted by the defect problems. Disclosure of Invention In order to solve the technical problems of inaccurate predicted temperature and serious misleading of steel judgment due to dependence on an energy integral model, the invention provides a temperature feedback control method and a temperature feedback control system for a smelting stage of a flat molten pool of an electric arc furnace, and the adopted technical scheme is as follows: the invention provides a temperature feedback control method for a smelting stage of a flat molten pool of an electric arc furnace, which comprises the following steps: Obtaining a measured temperature of molten steel in response to the smelting entering a flat melting pool stage; According to the current signals and vibration signals of all channels, the arc force amplitude and vibration response amplitude of all channels are periodically extracted, and the arc force index and vibration response index are respectively standardized and then obtained; judging whether the discrete degree of the electric arc force index in the queue meets the validity condition or not according to each channel, if so, fitting to obtain a vibration force transmission ratio according to all data pairs in the queue, determining the reliability of a vibration signal according to the correlation between the electric arc force index in the queue and a vibration response index, and determining the real-time electric energy thermal efficiency of the channel according to preset efficiency parameters, transmission ratio and reliability; Correcting the real-time electric power based on the real-time electric energy thermal efficiency, and combining the preset chemical reaction thermal power and the preset heat loss power to determine the net heating power of the molten steel; and controlling a smelting end point according to the predicted temperature, and executing corresponding optimized smelting operation according to the real-time electric energy thermal efficiency. The furnace wall vibration signal comprises a vibration acceleration sensor which is arranged on the outer wall of the electric arc furnace shell and corresponds to the physical position of each phase electrode, and the acquired furnace wall vibration acceleration instantaneous value of each region; the arc force index and vibration response index obtaining process comprises the following steps: The method comprises the steps of obtaining a current signal, carrying out square operation on current instantaneous values at all collecting moments in the current signal to obtain current square values, and generating an arc force equivalent signal proportional to the Lorentz force of an arc according to the current square values at all collecting moments in time sequence; For each electrode channel, acquiring a current square value sequence and a vibration acceleration instantaneous val