Rectangular six-electrode ac furnace constant impedance control system and method

Abstract

This invention relates to a constant impedance control system and method for a rectangular six-electrode AC electric furnace, belonging to the field of electrometallurgical equipment technology. It uses an optimized short-grid system to set initial impedance values ​​under different operating conditions. Current and voltage detection units are installed at the low-voltage output terminals of each electrode to detect the current and voltage data of the electric arc. A constant impedance PID controller compares the calculated actual impedance value with the set impedance value, thereby adjusting the electrode via an electrode regulator to maintain impedance stability. Three-phase power imbalance is used as the judgment criterion. Based on a novel rectangular six-electrode electric furnace, this invention provides a precise constant impedance electrode adjustment method for this type of furnace, solving the problems of slow electrode control response, adjustment lag, and neglect of strong three-phase coupling in existing technologies, significantly improving the furnace's operational stability and energy efficiency.

Description

Technical Field

[0001] This invention belongs to the field of electrometallurgical equipment technology, and relates to a constant impedance control system and method for a rectangular six-electrode AC electric furnace. Background Technology

[0002] Rectangular six-electrode AC furnaces, which have been developed in recent years, generally suffer from short-circuit impedance imbalance. In addition, traditional AC furnaces mostly use three-phase three-electrode systems, whose electrode control suffers from slow response speed, lag in adjustment, and neglect of the effects of strong three-phase coupling, resulting in low natural power factor and affecting smelting efficiency.

[0003] Therefore, there is an urgent need for a constant impedance control method and system to adapt to rectangular six-electrode AC furnaces, so as to achieve precise control and improve smelting efficiency. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a constant impedance control system and method for a rectangular six-electrode AC electric furnace.

[0005] To achieve the above objectives, the present invention provides the following technical solution: On one hand, the present invention provides a constant impedance control system for a rectangular six-electrode AC electric furnace, including a short grid system, a current detection unit, a voltage detection unit, a signal processing unit, a constant impedance PID controller, an electrode regulator, and a power judgment unit; The short network system is used to connect the six electrodes of the rectangular six-electrode AC furnace with three single-phase transformers; The current detection unit is installed at the low-voltage output terminal of the transformer and is used to collect arc current in real time. The voltage detection unit is installed between the electrode and the bottom of the AC electric furnace for real-time acquisition of arc voltage; The signal processing unit is used to calculate real-time impedance based on current and voltage. The constant impedance PID controller is used to compare the real-time impedance with the set impedance and output an adjustment signal. The electrode adjuster is used to control the raising and lowering of the electrode according to the adjustment signal; The power judgment unit is used to calculate the three-phase power imbalance and dynamically correct the set impedance value.

[0006] Furthermore, in the short network system, the six electrodes are arranged in a line, and the short networks containing the six electrodes are the six phases ABCDEF, where AB, CD, and EF are one of the three circuits, used to connect three single-phase transformers respectively. The short network increases the inter-circuit spacing while determining the spacing within the circuits.

[0007] Furthermore, the current detection unit is a current transformer or a Rogowski coil, which is installed at the six low-voltage side output terminals of the three single-phase transformers to detect the current flowing through the arc.

[0008] Furthermore, the voltage detection unit is a voltage transformer or a Hall coil, which is installed between the electrode and the furnace bottom to measure the six-segment arc voltage.

[0009] Furthermore, the constant impedance PID controller is a fuzzy adaptive PID controller, whose fuzzy rules are constructed based on impedance error and current change rate, realizing the adaptive performance of the PID controller in judging the actual arc impedance and the set impedance error.

[0010] Furthermore, after receiving the signal, the electrode adjuster controls the hydraulic transmission system to adjust the electrode lifting and lowering, thereby achieving impedance adjustment.

[0011] Furthermore, when the power judgment unit detects that the three-phase power imbalance exceeds a preset value, it triggers dynamic correction of the impedance setting value.

[0012] On the other hand, the present invention provides a constant impedance control method for a rectangular six-electrode AC electric furnace, based on the above system, comprising the following steps: S1: Optimize the design of the short network system to connect the six electrodes and three single-phase transformers, reduce impedance and impedance imbalance for system compensation; S2: Based on the optimized short network system, set the initial values ​​of arc impedance for multiple operating conditions; S3: The current and voltage of the electric arc are detected in real time by the current detection unit and the voltage detection unit, respectively; S4: Calculate the real-time impedance value of the electric arc through the data processing unit; S5: Input the real-time impedance value of the electric arc into the constant impedance PID controller and make an error judgment with the impedance value set under this working condition. If it is less than the predetermined value, then make a three-phase power imbalance judgment. If it is greater than or equal to the predetermined value, then transmit the signal to the electrode regulator. S6: After receiving the signal, the electrode regulator adjusts the arc impedance by raising and lowering the electrode. S7: Perform a three-phase power imbalance judgment. If it is less than the set value, maintain the original state. If it is greater than or equal to the set value, dynamically correct the impedance setting value. S8: Repeat steps S3 to S7.

[0013] The beneficial effects of this invention are as follows: (1) Optimize the short network system, reduce the strong coupling effect between phases, reduce impedance and impedance imbalance for system compensation, and provide a good foundation for the electrode control system.

[0014] (2) Accurately measure the current and voltage of the electric arc, and combine it with a fuzzy adaptive PID controller. Through a constant impedance electrode adjustment strategy, high-precision and dynamic electrode control is achieved under a rectangular six-electrode AC furnace, solving the problems of slow electrode control response, adjustment lag, and neglect of strong three-phase coupling in the existing technology. The short-circuit impedance imbalance has been reduced to <3%; the electrode adjustment response time has been shortened to <200ms; and the three-phase power imbalance has been controlled within ±5%.

[0015] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0016] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein: Figure 1 This is a flowchart of a constant impedance control method for a rectangular six-electrode AC furnace. Detailed Implementation

[0017] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0018] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0019] In the following description, numerous details are explored to provide a more thorough explanation of embodiments of the invention. However, it will be apparent to those skilled in the art that embodiments of the invention may be practiced without these specific details. In other embodiments, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring embodiments of the invention.

[0020] Example 1: This invention provides a constant impedance control system for a rectangular six-electrode AC electric furnace, comprising an optimized short grid system for the rectangular six-electrode AC electric furnace, a current detection unit, a voltage detection unit, a signal processing unit, a constant impedance PID controller, an electrode regulator, and a power judgment unit.

[0021] The current detection unit is installed at the low-voltage output terminal of the transformer to collect arc current in real time. The voltage detection unit is installed between the electrode and the furnace bottom to collect the arc voltage in real time; The signal processing unit is used to calculate the real-time impedance based on current and voltage. A constant impedance PID controller is used to compare the real-time impedance with the set impedance and output an adjustment signal; Electrode regulator, used to control the raising and lowering of the electrodes according to the adjustment signal; The power judgment unit is used to calculate the three-phase power imbalance and dynamically correct the set impedance value.

[0022] The optimized short grid system of the rectangular six-electrode AC furnace has six electrodes arranged in a line. The short grid containing the six electrodes consists of six phases: ABCDEF. AB, CD, and EF are one of three circuits connected to three single-phase transformers. Under the premise of determining the spacing within the circuits, reasonably increasing the spacing between the circuits (i.e., the spacing between phases BC and DE) can effectively reduce the impedance imbalance of the short grid.

[0023] The current detection unit can be a current transformer or a Rogowski coil, etc., and is installed on the six low-voltage side output terminals of the three single-phase transformers to detect the current flowing through the arc.

[0024] The voltage detection unit can be a voltage transformer or a Hall coil, etc., and is installed between the electrode and the furnace bottom to measure the six arc voltages.

[0025] The signal processing unit receives current and voltage data and calculates the impedance value.

[0026] The constant impedance PID controller can be a fuzzy adaptive PID controller. Its fuzzy rules are constructed based on impedance error and current change rate, realizing the adaptive performance of the PID controller in judging the error between the actual arc impedance and the set impedance. The error between the actual arc impedance and the set impedance is judged against a predetermined value, i.e., whether it is less than the predetermined value. If it is, it directly enters the power judgment unit; if not, the impedance error signal is transmitted to the electrode regulator.

[0027] After receiving the signal, the electrode regulator controls the hydraulic transmission system to adjust the electrode lifting and lowering to achieve impedance regulation. The power judgment unit calculates the power and three-phase power imbalance by measuring the arc current and voltage, and compares it with the set value of 5%. It determines whether the three-phase power imbalance of the arc power is less than 5%. If so, the state is maintained; if not, the impedance set value is dynamically corrected, and then the arc current and voltage are re-detected, and the above operation is repeated.

[0028] Example 2: like Figure 1 As shown, this embodiment provides a constant impedance control method for a rectangular six-electrode AC electric furnace, based on the system described in Embodiment 1, and includes the following steps: S1. Optimize the design of the short network system to connect the six electrodes and three single-phase transformers, reduce impedance and impedance imbalance for system compensation; S2. Based on the optimized short network system, set the initial values ​​of arc impedance for multiple operating conditions; S3. The real-time current and voltage of the electric arc are detected by the current detection unit and the voltage detection unit; S4. Calculate the real-time impedance value of the electric arc through the data processing unit; S5. Input the real-time impedance value of the electric arc into the constant impedance PID controller and compare it with the impedance value set under this working condition to determine the error. If it is less than the predetermined value, then determine the three-phase power imbalance. If it is greater than or equal to the predetermined value, then transmit the signal to the electrode regulator. S6. After receiving the signal, the electrode adjuster adjusts the arc impedance by raising and lowering the electrode. S7. Perform a three-phase power imbalance judgment. If it is less than the set value, maintain the original state. If it is greater than or equal to the set value, dynamically correct the impedance setting value. S8. Then re-detect the current and voltage of the arc and repeat the above operation.

[0029] This embodiment can accurately measure the current and voltage of the electric arc. Combined with a fuzzy adaptive PID controller, it achieves high-precision and dynamic electrode control under a rectangular six-electrode AC furnace through a constant impedance electrode adjustment strategy. This solves the problems of slow electrode control response, lag in adjustment, and neglect of strong three-phase coupling in the prior art.

[0030] Example 3: An electronic device, comprising a memory and a processor; The memory is used to store computer programs; The processor is configured to implement the method described in Embodiment 1 when executing the computer program.

[0031] Example 4: A computer-readable storage medium storing a computer program that, when executed by a processor, implements the method described in Embodiment 1.

[0032] Example 5: A computer program product includes a computer program that, when executed by a processor, implements the method described in Example 1.

[0033] In the above embodiments, the reference to "this embodiment" in the specification indicates that a specific feature, structure, or characteristic described in connection with the embodiment is included in at least some embodiments, but not necessarily all embodiments. Multiple appearances of "this embodiment" do not necessarily refer to the same embodiment.

[0034] In the above embodiments, although the invention has been described in conjunction with specific embodiments thereof, many substitutions, modifications, and variations of these embodiments will be apparent to those skilled in the art from the foregoing description. For example, other memory structures (e.g., dynamic RAM (DRAM)) may be used with the embodiments discussed. The embodiments of the invention are intended to cover all such substitutions, modifications, and variations falling within the broad scope of the appended claims.

[0035] As will be understood by those skilled in the art, the computer-readable storage medium described in this embodiment allows for the implementation of all or part of the steps in the above method embodiments by computer program-related hardware. The aforementioned computer program can be stored in a computer-readable storage medium. When executed, the program performs the steps of the above method embodiments; and the aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks.

[0036] The electronic terminal provided in this embodiment includes a processor, a memory, a transceiver, and a communication interface. The memory and the communication interface are connected to the processor and the transceiver and complete communication between them. The memory is used to store computer programs, the communication interface is used to perform communication, and the processor and the transceiver are used to run the computer programs, so that the electronic terminal performs the steps of the above method.

[0037] In this embodiment, the memory may include random access memory (RAM) and may also include non-volatile memory, such as at least one disk storage device.

[0038] The processors mentioned above can be general-purpose processors, including central processing units (CPUs), network processors (NPs), etc.; they can also be digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0039] This invention can be used in a wide range of general-purpose or special-purpose computing system environments or configurations. Examples include: personal computers, server computers, handheld or portable devices, tablet devices, multiprocessor systems, microprocessor-based systems, set-top boxes, programmable consumer electronics, network PCs, minicomputers, mainframe computers, and distributed computing environments including any of the above systems or devices, etc.

[0040] This invention can be described in the general context of computer-executable instructions, such as program modules, that are executed by a computer. Generally, program modules include routines, programs, objects, components, data structures, etc., that perform a specific task or implement a specific abstract data type. This invention can also be practiced in distributed computing environments where tasks are performed by remote processing devices connected via a communication network. In distributed computing environments, program modules can reside in local and remote computer storage media, including storage devices.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A constant impedance control system for a rectangular six-electrode AC furnace, characterized in that: It includes a short-circuit system, a current detection unit, a voltage detection unit, a signal processing unit, a constant impedance PID controller, an electrode regulator, and a power judgment unit; The short network system is used to connect the six electrodes of the rectangular six-electrode AC furnace with three single-phase transformers; The current detection unit is installed at the low-voltage output terminal of the transformer and is used to collect arc current in real time. The voltage detection unit is installed between the electrode and the bottom of the AC electric furnace for real-time acquisition of arc voltage; The signal processing unit is used to calculate real-time impedance based on current and voltage. The constant impedance PID controller is used to compare the real-time impedance with the set impedance and output an adjustment signal. The electrode adjuster is used to control the raising and lowering of the electrode according to the adjustment signal; The power judgment unit is used to calculate the three-phase power imbalance and dynamically correct the set impedance value.

2. The constant impedance control system for a rectangular six-electrode AC furnace according to claim 1, characterized in that: The short network system has six electrodes arranged in a line, and the short networks containing the six electrodes are the six phases ABCDEF. Among them, AB, CD, and EF are one of the three circuits, which are used to connect three single-phase transformers respectively. The short network increases the inter-circuit spacing while determining the spacing within the circuit.

3. The constant impedance control system for a rectangular six-electrode AC furnace according to claim 1, characterized in that: The current detection unit is a current transformer or a Rogowski coil, which is installed at the six low-voltage side output terminals of the three single-phase transformers to detect the current flowing through the arc.

4. The constant impedance control system for a rectangular six-electrode AC furnace according to claim 1, characterized in that: The voltage detection unit is a voltage transformer or a Hall coil, installed between the electrode and the furnace bottom to measure the six-segment arc voltage.

5. The constant impedance control system for a rectangular six-electrode AC furnace according to claim 1, characterized in that: The constant impedance PID controller is a fuzzy adaptive PID controller. Its fuzzy rules are constructed based on impedance error and current change rate, realizing the adaptive performance of the PID controller in judging the actual arc impedance and the set impedance error.

6. The constant impedance control system for a rectangular six-electrode AC furnace according to claim 1, characterized in that: After receiving the signal, the electrode adjuster controls the hydraulic transmission system to adjust the electrode lifting and lowering, thereby achieving impedance adjustment.

7. The constant impedance control system for a rectangular six-electrode AC furnace according to claim 1, characterized in that: When the power judgment unit detects that the three-phase power imbalance exceeds the preset value, it triggers dynamic correction of the impedance setting value.

8. A method for constant impedance control of a rectangular six-electrode AC furnace, characterized in that: The constant impedance control system for a rectangular six-electrode AC electric furnace according to any one of claims 1-7 includes the following steps: S1: Optimize the design of the short network system to connect the six electrodes and three single-phase transformers, reduce impedance and impedance imbalance for system compensation; S2: Based on the optimized short network system, set the initial values ​​of arc impedance for multiple operating conditions; S3: The current and voltage of the electric arc are detected in real time by the current detection unit and the voltage detection unit, respectively; S4: Calculate the real-time impedance value of the electric arc through the data processing unit; S5: Input the real-time impedance value of the electric arc into the constant impedance PID controller and make an error judgment with the impedance value set under this working condition. If it is less than the predetermined value, then make a three-phase power imbalance judgment. If it is greater than or equal to the predetermined value, then transmit the signal to the electrode regulator. S6: After receiving the signal, the electrode regulator adjusts the arc impedance by raising and lowering the electrode. S7: Perform a three-phase power imbalance judgment. If it is less than the set value, maintain the original state. If it is greater than or equal to the set value, dynamically correct the impedance setting value. S8: Repeat steps S3 to S7.

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