A direct current power supply based electric arc furnace and control method

Abstract

The present application relates to the field of metallurgical equipment, and discloses a direct current power supply based ore smelting furnace and control method, comprising: an electrode, the electrode comprising a cathode electrode and symmetrically distributed first and second anode electrodes, the electrode penetrating through the top of the furnace body and extending into the furnace; a rectifier set, the rectifier set being connected with the two anode electrodes through a positive bus and connected with the cathode electrode through a negative bus; the rectifier set being configured with a trigger adjustment control strategy. Thus, accurate adjustment of the direct current and uniform distribution of the current are realized, and stable transmission of the power of the ore smelting furnace and continuous and stable combustion are ensured.

Description

Technical Field

[0001] This invention relates to the field of metallurgical equipment, specifically to a submerged arc furnace based on DC power supply and its control method. Background Technology

[0002] Submerged arc furnaces are core equipment used in industries such as metallurgy and chemical engineering to produce high-temperature molten materials such as ferroalloys and calcium carbide. Traditional submerged arc furnaces generally use a three-phase AC power supply, which inputs electrical energy into the furnace through three electrodes arranged in a triangle.

[0003] The existing smelting process in electric arc furnaces, especially in the AC power supply process, often has the following technical problems: First, traditional AC-powered submerged arc furnaces suffer from alternating thermal stress and severe losses due to the periodic polarity reversal of the three-phase current. They also have inherent defects such as three-phase power imbalance and arc dynamic instability, resulting in high energy consumption and product quality fluctuations during the smelting process. Secondly, existing DC smelting retrofit solutions typically require extensive adjustments or even replacements of the furnace body and related power supply equipment, resulting in high retrofit costs. Furthermore, during long-term operation, the electrodes are still prone to localized overheating and accelerated wear, further shortening electrode lifespan and affecting the stability of the smelting system. Summary of the Invention

[0004] The summary section of this invention provides a brief overview of the concepts, which will be described in detail in the detailed description section below. This summary section is not intended to identify key or essential features of the claimed technical solutions, nor is it intended to limit the scope of the claimed technical solutions.

[0005] This invention proposes a DC-powered submerged arc furnace and its control method to solve one or more of the technical problems mentioned in the background section above.

[0006] This invention provides a DC-powered submerged arc furnace, comprising: The electrode includes a cathode electrode and an anode electrode. The anode electrode includes a first anode electrode and a second anode electrode. The electrode passes through the top of the furnace body and extends into the furnace. The first anode electrode and the second anode electrode are symmetrically distributed on both sides of the cathode electrode. The rectifier unit is connected to the first anode electrode and the second anode electrode through the positive bus and to the cathode electrode through the negative bus. The rectifier unit is equipped with a trigger regulation control strategy. The furnace body is used to contain the molten material and support the electrodes.

[0007] Optionally, the electrode is connected to the DC bus of the rectifier unit via a water-cooled copper clamp located at the top, and the water-cooled copper clamp has a cooling water channel inside.

[0008] Optionally, the electrode is a self-baking electrode, and the electrode has a corresponding electrode diameter; and The electrode diameter is determined by the following formula:

[0009] in, The diameter of the electrode; The current flowing through the electrodes; denoted as current density.

[0010] Optionally, the cathode electrode has a corresponding cathode electrode diameter; and The diameter of the cathode electrode is determined by the following formula:

[0011] in, The diameter of the cathode electrode; The total power of the electric arc furnace; The voltage of the DC bus; This represents the maximum cathode current density corresponding to the cathode.

[0012] Optionally, the anode electrode has a corresponding anode electrode diameter; and The diameter of the anode electrode is determined by the following formula:

[0013] in, The diameter of the anode electrode; The total power of the electric arc furnace; The voltage of the DC bus; This represents the maximum current density at the anode.

[0014] Optionally, the rectifier unit adopts a double anti-star rectifier circuit; and The trigger adjustment control strategy is as follows: based on the voltage and current of the DC bus and the real-time current of each rectifier bridge arm in the rectifier unit, the corresponding trigger angle adjustment amount is obtained, and a control command for the trigger angle is generated according to the 120° phase difference between the three phases.

[0015] Optionally, the DC-powered submerged arc furnace control method of the present invention, applied in a DC-powered submerged arc furnace of the present invention, includes: Obtain the real-time current corresponding to the DC bus; The real-time current is compared with the first current threshold and the second current threshold respectively to obtain the comparison results; If the comparison result indicates that the real-time current is less than or equal to the first current threshold, a first control command for the trigger angle is generated. If the comparison result indicates that the real-time current is greater than or equal to the second current threshold, a second control command for the trigger angle is generated.

[0016] Optionally, generate a first control command for the firing angle, including: Based on the real-time current and the first current threshold, the first current deviation corresponding to the real-time current is obtained; The real-time trigger angle is obtained, and a first control command is generated based on the first current deviation and the real-time trigger angle.

[0017] Optionally, a second control command is generated for the firing angle, including: Based on the real-time current and the second current threshold, the second current deviation corresponding to the real-time current is obtained; The real-time trigger angle is obtained, and a second control command is generated based on the second current deviation and the real-time trigger angle.

[0018] The present invention has the following beneficial effects: 1. Improved energy efficiency and operational stability of the submerged arc furnace. Specifically, the adoption of a single-cathode, dual-anode DC power supply structure effectively eliminates the alternating thermal stress on the electrodes caused by periodic commutation in traditional AC furnaces, significantly extending electrode lifespan. Simultaneously, DC power supply avoids the skin effect and proximity effect of AC power, reducing energy loss. Combined with a trigger-based regulation control strategy, it ensures uniform current distribution and continuous, stable arc combustion, thereby reducing power consumption and improving the uniformity of the thermal field within the furnace. 2. Improved the long-term reliability of the metallurgical system. Specifically, by modifying the original furnace body, the modification cost was significantly reduced, overcoming the need for large-scale system modifications commonly found in existing DC smelting schemes, and avoiding the economic bottleneck caused by replacing the entire furnace body and related power supply equipment. Simultaneously, by applying the principles of current distribution and heat load balance, the optimal diameters of the cathode and anode electrodes were derived, ensuring that the electrodes operate within a safe current density range. This effectively prevents increased losses due to localized overheating, providing a solid guarantee for the long-term stable operation of the metallurgical system. Attached Figure Description

[0019] The above and other features, advantages, and aspects of the various embodiments of the present invention will become more apparent from the accompanying drawings and the following detailed description. Throughout the drawings, the same or similar reference numerals denote the same or similar elements. It should be understood that the drawings are schematic, and elements are not necessarily drawn to scale.

[0020] Figure 1 This is a schematic diagram of the structure of a DC-powered electric arc furnace according to the present invention; Figure 2 This is a flowchart of a DC-powered submerged arc furnace control method according to the present invention; Figure 3 This is a flowchart of the generation of the first control command in a DC-powered submerged arc furnace control method according to the present invention. Detailed Implementation

[0021] The invention will now be described in more detail with reference to the accompanying drawings. While some embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the invention. It should be understood that the drawings and embodiments of the invention are for illustrative purposes only and are not intended to limit the scope of protection of the invention.

[0022] It should also be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings. Unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0023] It should be noted that the concepts of "first" and "second" mentioned in this invention are only used to distinguish different devices, modules or units, and are not used to limit the order of functions performed by these devices, modules or units or their interdependencies.

[0024] It should be noted that the terms "a" and "a plurality of" used in this invention are illustrative rather than restrictive. Those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0025] The names of messages or information exchanged between the various devices of this invention are for illustrative purposes only and are not intended to limit the scope of these messages or information.

[0026] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0027] like Figure 1 The diagram shown is a structural schematic of a DC-powered submerged arc furnace system according to the present invention, specifically including: The electrode includes a cathode electrode 2 and an anode electrode. The anode electrode includes a first anode electrode 3 and a second anode electrode 4. The electrode passes through the top of the furnace body 1 and extends into the furnace. The first anode electrode 3 and the second anode electrode 4 are symmetrically distributed on both sides of the cathode electrode 2.

[0028] In some embodiments, such as Figure 1As shown, the electrodes can be graphite electrodes, and are respectively configured as cathode electrode 2 and anode electrodes. There is one cathode electrode 2 and two anode electrodes. The three electrodes pass through the top of the furnace body 1 and extend into the interior of the furnace body 1. The two anode electrodes are distributed on both sides of the cathode electrode 2, forming a triangular layout, thus forming a single-cathode, double-anode DC power supply structure. The single-cathode, double-anode DC power supply structure refers to a single cathode electrode 2 set in the center and two anode electrodes symmetrically arranged on both sides, which is used to improve current distribution and arc stability.

[0029] The rectifier unit 5 is connected to the first anode electrode 3 and the second anode electrode 4 via the positive bus 7, and to the cathode electrode 2 via the negative bus 6. The rectifier unit 5 is equipped with a trigger regulation control strategy.

[0030] In some embodiments, the first anode electrode 3 and the second anode electrode 4 are connected to the rectifier unit 5 via the positive bus 7, and the cathode electrode 2 is connected to the rectifier unit 5 via the negative bus 6. The rectifier unit 5 is equipped with a trigger regulation control strategy to ensure that the three-phase current is evenly distributed to the first anode electrode 3 and the second anode electrode 4 after rectification, avoiding arc instability caused by current deviation. Furthermore, by adjusting the trigger angle of the rectifier unit 5, stable power transmission and continuous stable arc combustion are achieved. The 120° phase difference refers to the 120° phase difference between the three-phase voltages output by the three-phase AC power supply. In the rectifier unit 5, when the three-phase current is rectified into DC, maintaining a 120° phase difference ensures that the three-phase current is evenly distributed to each anode, avoiding single-phase overload or arc instability. The rectifier unit can be a rectifier device for converting three-phase AC power into DC power, and can consist of a rectifier transformer and multiple rectifier bridge arms. The rectifier transformer is used to achieve voltage level matching and power supply regulation. The rectifier bridge arm is used to rectify and convert the AC power output from the rectifier transformer.

[0031] Furnace body 1 is used to contain the molten material and support the electrodes.

[0032] In some embodiments, the furnace body 1 of the submerged arc furnace is used to contain the molten material and provide mechanical support and fixed position for the electrodes, thereby ensuring the stable arrangement and safe operation of the electrodes during the molten process. In practice, the original furnace body 1 can be modified to reduce economic costs.

[0033] These embodiments improve the energy efficiency and operational stability of the submerged arc furnace. Specifically, the adoption of a single-cathode, dual-anode DC power supply structure effectively eliminates the alternating thermal stress on the electrodes caused by periodic commutation in traditional AC furnaces, significantly extending electrode lifespan. Simultaneously, DC power supply avoids the skin effect and proximity effect of AC power, reducing energy loss. Combined with a trigger-based regulation control strategy, this ensures uniform current distribution and continuous, stable arc combustion, thereby reducing power consumption and improving the uniformity of the thermal field within the furnace.

[0034] In some embodiments, to further address the second technical problem described in the background section, namely, "existing DC submerged arc furnace technologies typically require structural modifications to the furnace structure or the entire power supply system, resulting in high modification costs. Simultaneously, long-term electrode operation inevitably leads to localized overheating and increased wear, resulting in shortened electrode lifespan and reduced metallurgical system stability," in some embodiments of the present invention, the electrode is connected to the DC bus of the rectifier unit 5 via a top-mounted water-cooled copper clamp, the water-cooled copper clamp having internal cooling water channels.

[0035] In some embodiments, the top of the electrode is connected to the DC bus of the rectifier unit 5 via a water-cooled copper clamp. A cooling water channel is also provided inside the water-cooled copper clamp to achieve good conductivity and efficient heat dissipation, prevent the contact resistance from increasing due to local overheating, and improve the connection reliability.

[0036] The electrodes are self-baking electrodes, and each electrode has a corresponding electrode diameter; and The electrode diameter is determined by the following formula:

[0037] in, The diameter of the electrode; The current flowing through the electrodes; denoted as current density.

[0038] In some embodiments, the cathode electrode 2 can be a high-density self-baking electrode with excellent conductivity and high-temperature strength; the anode electrode can be a wear-resistant self-baking electrode (containing boron additives to enhance corrosion resistance) to enhance its erosion resistance under DC arc. The electrode diameter can be calculated based on the current density and the current passing through the electrode, thereby ensuring that the electrode operates within a safe current density range.

[0039] Among them, based on the current passing through the electrodes Electrode diameter The electrode cross-sectional area can be calculated as follows:

[0040] in, The cross-sectional area of ​​the electrode is... Given the electrode diameter, the current density is... It can be determined using the following formula: in, For current density, The cross-sectional area of ​​the electrode is... The current passing through the electrodes, Let be the electrode diameter. From this, the aforementioned formula can be derived to calculate the electrode diameter. .

[0041] Among them, cathode electrode 2 corresponds to the cathode electrode diameter; and The diameter of the cathode electrode is determined by the following formula:

[0042] in, The diameter of the cathode electrode; The total power of the electric arc furnace; The voltage of the DC bus; This represents the maximum cathode current density corresponding to the cathode.

[0043] In some embodiments, the cathode electrode 2 requires higher conductivity to cope with the high thermal load from the total current; the anode electrode requires better wear resistance to withstand arc impact. Due to their differences in materials and functions, their maximum safe current densities are different, therefore the cathode electrode 2 corresponds to a cathode electrode diameter, and the anode electrode corresponds to an anode electrode diameter.

[0044] The total DC current can be obtained using the following formula, based on the total power of the electric arc furnace and the DC bus voltage:

[0045] in, This is the total DC current. The total power of the electric arc furnace. This is the voltage of the DC bus.

[0046] Since cathode electrode 2 needs to carry the current flowing into the first anode electrode 3 and the second anode electrode 4, the cathode current carrying capacity is:

[0047] in, For the cathode to carry current, Given the total DC current, the current carried by each anode electrode is: in, The current carried by each anode electrode, This represents the total DC current.

[0048] Based on this, and combined with the aforementioned electrode diameter formula, the cathode electrode diameter corresponding to cathode electrode 2 can be derived:

[0049] in, The diameter of the cathode electrode; The total power of the electric arc furnace; The voltage of the DC bus; This represents the maximum cathode current density. This represents the total DC current.

[0050] Among them, the anode electrode corresponds to the anode electrode diameter; and The diameter of the anode electrode is determined by the following formula:

[0051] in, The diameter of the anode electrode; The total power of the electric arc furnace; The voltage of the DC bus; This represents the maximum current density at the anode.

[0052] In some embodiments, the diameter of the anode electrode corresponding to the anode electrode can be derived by the following formula: in, This is the total DC current. The diameter of the anode electrode; The total power of the electric arc furnace; The voltage of the DC bus; This represents the maximum current density at the anode.

[0053] Among them, rectifier unit 5 adopts a double anti-star rectifier circuit; and The trigger adjustment control strategy is as follows: based on the voltage and current of the DC bus and the real-time current of each rectifier bridge arm in the rectifier unit, the corresponding trigger angle adjustment amount is obtained, and a control command for the trigger angle is generated according to the 120° phase difference between the three phases.

[0054] In some embodiments, the rectifier unit 5 may employ a double-reverse star rectifier circuit to convert three-phase AC power into DC power. This double-reverse star rectifier circuit can be composed of two sets of three-phase star rectifier bridges connected in parallel, with current balancing between the two bridges achieved through a balancing reactor, thereby obtaining a higher output current capability under the same transformer secondary voltage conditions. The double-reverse star rectifier circuit refers to a rectifier topology structure consisting of two sets of three-phase star rectifier units connected in reverse, with current sharing on the DC side achieved through a balancing reactor. A balancing reactor is a reactive device used to provide current sharing and suppress current imbalance between parallel rectifier units. The transformer secondary voltage refers to the AC voltage output from the secondary side of the rectifier transformer, used to provide the pre-rectification voltage input to the rectifier circuit. The secondary side of the transformer has a conventional structure, used to provide operating voltage to the corresponding load.

[0055] The controller in rectifier unit 5 can acquire the voltage and current of the DC bus and the current signals of each rectifier bridge arm in real time through configured voltage and current transformers. The built-in controller in rectifier unit 5 can calculate the firing angle adjustment based on the acquired voltage and current, and generate three sets of trigger control commands by combining the 120° phase difference between the three-phase AC currents, thereby achieving balanced distribution of the three-phase current and stable control of the rectified output. The firing angle adjustment can be used to ensure stable arc combustion and prevent overcurrent or insufficient output. The controller refers to the electrical control unit built into the rectifier unit, which can generate control commands based on the acquired electrical signals.

[0056] One of the methods for controlling a submerged arc furnace based on DC power supply is applied to a submerged arc furnace based on DC power supply, and includes: Step 1: Obtain the real-time current corresponding to the DC bus.

[0057] In some embodiments, such as Figure 2 The diagram shows a flowchart of a DC-powered submerged arc furnace control method according to the present invention. The execution subject can be the controller built into the rectifier unit 5. The execution subject can obtain the real-time current corresponding to the DC bus by reading the data monitored by the current detection device (such as a Hall current sensor) set in the DC bus circuit.

[0058] Step 2: Compare the real-time current with the first current threshold and the second current threshold respectively to obtain the comparison results.

[0059] In some embodiments, the first current threshold is used to represent the lower limit of the DC bus current, reflecting the minimum requirement for normal operating current; for example, the first current threshold may be 48kA. The second current threshold is used to represent the upper limit of the DC bus current, corresponding to the maximum safe current allowed by the system; for example, the second current threshold may be 52kA. The executing entity can compare the read real-time current with the first current threshold and the second current threshold respectively to obtain the comparison result.

[0060] If the comparison result indicates that the real-time current is less than or equal to the first current threshold, a first control command for the trigger angle is generated.

[0061] In some embodiments, when the comparison result shows that the real-time current is less than or equal to a first current threshold, it indicates that the DC output current is too low, which may lead to arc instability or insufficient melting power. At this time, the controller can generate a first control command to reduce the firing angle of the rectifier unit 5, thereby advancing the thyristor turn-on time, increasing the output voltage and current, and allowing the arc to reignite stably and remain within the set power range. For example, under a rated current of 50kA, if the detected current is less than 48kA (e.g., 45kA), the controller can reduce the firing angle from the originally set 25° to 22°, thereby increasing the output current to enhance the arc's combustion stability and maintain melting continuity.

[0062] If the comparison result indicates that the real-time current is greater than or equal to the second current threshold, a second control command for the trigger angle is generated.

[0063] In some embodiments, when the comparison result shows that the real-time current is greater than or equal to the second current threshold, it indicates that there is an overcurrent risk in the system, which may cause electrode overheating or rectifier unit 5 overload. At this time, the controller can generate a second control command to increase the firing angle of rectifier unit 5 to delay the thyristor turn-on time, reduce the output voltage and current, thereby achieving current limiting protection. For example, under a rated current of 50kA, if the detected current is greater than 52kA (e.g., 56kA), the controller can increase the firing angle from 25° to 28° to reduce the output current, prevent overheating damage, and maintain safe system operation.

[0064] The generation of the first control command for the trigger angle includes: Step 1: Based on the real-time current and the first current threshold, obtain the first current deviation corresponding to the real-time current.

[0065] In some embodiments, such as Figure 3The diagram shows a flowchart of the generation of the first control command in a DC-powered submerged arc furnace control method according to the present invention. If the real-time current is less than or equal to a first current threshold, the executing entity can first perform a difference calculation between the first current threshold and the real-time current, and then calculate the percentage of the difference to obtain the first current deviation corresponding to the real-time current.

[0066] Step 2: Obtain the real-time trigger angle and generate the first control command based on the first current deviation and the real-time trigger angle.

[0067] In some embodiments, the real-time trigger angle can be obtained from the trigger angle register of the controller. Then, the first current deviation is multiplied by a preset negative adjustment ratio coefficient to obtain a negative adjustment amount. Finally, the real-time trigger angle is added to the negative adjustment amount to obtain the updated trigger angle, and a first control command is generated based on the target trigger angle. For example, if the real-time trigger angle is 25°, the first current deviation is 5%, and the preset negative adjustment ratio coefficient is 60 (the trigger angle is adjusted by 0.6° for every 1% current deviation), then the updated trigger angle can be 22°.

[0068] The generation of a second control command for the trigger angle includes: Step 1: Based on the real-time current and the second current threshold, obtain the second current deviation corresponding to the real-time current.

[0069] In some embodiments, if the real-time current is greater than or equal to the second current threshold, the executing entity can first perform a difference calculation on the real-time current and the second current threshold, and then calculate the percentage of the difference to obtain the second current deviation corresponding to the real-time current.

[0070] Step 2: Obtain the real-time trigger angle, and generate the second control command based on the second current deviation and the real-time trigger angle.

[0071] In some embodiments, the real-time trigger angle can be obtained from the trigger angle register of the controller. Then, the second current deviation is multiplied by a preset positive adjustment ratio coefficient to obtain a positive adjustment amount. Finally, the real-time trigger angle is added to the positive adjustment amount to obtain the updated trigger angle, and a second control command is generated based on this increased target trigger angle. For example, if the real-time trigger angle is 25°, the second current deviation is 5%, and the preset positive adjustment ratio coefficient is 60 (the trigger angle is adjusted by 0.6° for every 1% current deviation), then the updated trigger angle can be 28°.

[0072] These embodiments improve the long-term reliability of the metallurgical system. Specifically, by modifying the original furnace body, the modification cost is significantly reduced, overcoming the need for large-scale system modifications commonly found in existing DC smelting schemes, and avoiding the economic bottleneck caused by replacing the entire furnace body and related power supply equipment. Simultaneously, by applying the principles of current distribution and heat load balance, reasonable diameters for the cathode and anode electrodes are derived, ensuring that the electrodes operate within a safe current density range. This effectively avoids increased losses due to localized overheating, providing a solid guarantee for the long-term stable operation of the metallurgical system.

[0073] The above description is merely a selection of preferred embodiments of the present invention and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention is not limited to specific combinations of the above-described technical features, but also includes other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above-described features with (but not limited to) technical features with similar functions disclosed in this invention.

Claims

1. A submerged arc furnace based on DC power supply, characterized in that, include: The electrode includes a cathode electrode and an anode electrode. The anode electrode includes a first anode electrode and a second anode electrode. The electrode passes through the top of the furnace body and extends into the furnace. The first anode electrode and the second anode electrode are symmetrically distributed on both sides of the cathode electrode. A rectifier unit is provided, wherein the rectifier unit is connected to the first anode electrode and the second anode electrode respectively via a positive bus, and is connected to the cathode electrode via a negative bus. The rectifier unit is configured with a trigger regulation control strategy. A furnace body, which is used to contain the molten material and support the electrodes.

2. The submerged arc furnace based on DC power supply according to claim 1, characterized in that, The electrode is connected to the DC bus of the rectifier unit via a water-cooled copper clamp located at the top, and the water-cooled copper clamp has a cooling water channel inside.

3. The submerged arc furnace based on DC power supply according to claim 2, characterized in that, The electrode is a self-baking electrode, and the electrode has a corresponding electrode diameter; and The electrode diameter is determined by the following formula: in, The diameter of the electrode; The current flowing through the electrode; denoted as current density.

4. The electric arc furnace based on DC power supply according to claim 3, characterized in that, The cathode electrode corresponds to a cathode electrode diameter; and The diameter of the cathode electrode is determined by the following formula: in, The diameter of the cathode electrode; The total power of the electric arc furnace; The voltage of the DC bus; This represents the maximum cathode current density corresponding to the cathode.

5. The electric arc furnace based on DC power supply according to claim 4, characterized in that, The anode electrode corresponds to an anode electrode diameter; and The diameter of the anode electrode is determined by the following formula: in, The diameter of the anode electrode; The total power of the electric arc furnace; The voltage of the DC bus; This represents the maximum current density of the anode corresponding to the anode.

6. The submerged arc furnace based on DC power supply according to claim 5, characterized in that, The rectifier unit adopts a double anti-star rectifier circuit; and The trigger adjustment control strategy is as follows: based on the voltage and current of the DC bus and the real-time current of each rectifier bridge arm in the rectifier unit, the corresponding trigger angle adjustment amount is obtained, and a control command for the trigger angle is generated according to the 120° phase difference between the three phases.

7. A control method for a submerged arc furnace based on DC power supply, applied to the submerged arc furnace based on DC power supply as described in any one of claims 1-6, characterized in that, include: Obtain the real-time current corresponding to the DC bus; The real-time current is compared with the first current threshold and the second current threshold respectively to obtain the comparison results; If the comparison result indicates that the real-time current is less than or equal to the first current threshold, a first control command for the trigger angle is generated. If the comparison result indicates that the real-time current is greater than or equal to the second current threshold, a second control command for the trigger angle is generated.

8. The method for controlling a submerged arc furnace based on DC power supply according to claim 7, characterized in that, The generation of the first control command for the trigger angle includes: Based on the real-time current and the first current threshold, the first current deviation corresponding to the real-time current is obtained; The real-time trigger angle is obtained, and the first control command is generated based on the first current deviation and the real-time trigger angle.

9. The method for controlling a submerged arc furnace based on DC power supply according to claim 8, characterized in that, The generation of the second control command for the trigger angle includes: Based on the real-time current and the second current threshold, the second current deviation corresponding to the real-time current is obtained; The real-time trigger angle is obtained, and the second control command is generated based on the second current deviation and the real-time trigger angle.

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