A coiler torque control method, device and frequency converter

Abstract

The present invention discloses a coiler torque control method, device and frequency converter. The method includes: if the coiler is in the speed control mode, obtaining the actual operating speed and actual output current of the coiler; adjusting the speed set value based on the actual operating speed to determine the current set value of the coiler, wherein the speed set value is greater than the linear speed of the coiler; adjusting the current set value based on the actual output current to determine the actual torque value of the coiler; comparing the actual torque value with the torque set value, and selecting the smaller torque value as the target torque value; outputting the target torque value, and controlling the coiler to execute the corresponding control mode according to the target torque value. This method can effectively solve the technical problem that the quality of the strip steel is damaged due to large fluctuations in torque output during the switching process between the speed control and torque control of the coiler, and is beneficial to improving the smoothness of torque output during the switching process.

Description

Technical Field

[0001] The present invention relates to the technical field of continuous casting and rolling, and particularly relates to a coiler torque control method, device, and frequency converter. Background Art

[0002] As the last process of the continuous casting and rolling production line, the accurate and stable control of the coiler directly affects the quality of the finished steel coil. To ensure the quality of the steel coil, the coiler adopts a combination of speed control and torque control. Before the strip is tensioned, the coiler is in speed mode and runs at the rolling speed + traction speed to facilitate the coiler to build tension; during the process from when the strip enters the coiler to complete tension building until the pinch roll at the front of the coiler throws the strip during tailing, the coiler is always in torque control mode; when the pinch roll throws the strip during tailing, as the strip tension disappears, the coiler immediately switches to speed control mode.

[0003] Therefore, the speed control and torque control of the coiler need to be frequently switched according to different production steps, and the smoothness of torque output during the switching process directly affects the quality of the strip. Through the research on the speed control and torque control methods of the coiler, this application provides a coiler torque control method. Summary of the Invention

[0004] Embodiments of this application provide a coiler torque control method, device, and frequency converter, which can effectively solve the technical problem that the quality of the strip is damaged due to large fluctuations in torque output during the switching process between the speed control and torque control of the coiler, and is beneficial to improving the smoothness of torque output during the switching process.

[0005] In the first aspect, the present invention provides the following technical solution through an embodiment of the present invention:

[0006] A coiler torque control method is applied to a frequency converter, and the frequency converter is used to control the switching between the speed control mode and the torque control mode of the coiler. The method includes: if the coiler is in the speed control mode, obtain the actual operating speed and actual output current of the coiler; adjust the speed set value based on the actual operating speed to determine the current set value of the coiler, where the speed set value is greater than the linear speed of the coiler; adjust the current set value based on the actual output current to determine the actual torque value of the coiler; compare the actual torque value with the torque set value, and select the smaller torque value as the target torque value; output the target torque value, and control the coiler to execute the corresponding control mode according to the target torque value.

[0007] Preferably, controlling the coiler to execute a corresponding control mode according to the target torque value includes: if the actual torque value is used as the target torque value, controlling the coiler to execute the speed control mode; if the torque set value is used as the target torque value, controlling the coiler to switch from the speed control mode to the torque control mode.

[0008] Preferably, after controlling the coiler to switch from the speed control mode to the torque control mode, the method further includes: comparing the actual operating speed with the speed set value; if the actual operating speed is greater than or equal to the speed set value, controlling the coiler to switch from the torque control mode to the speed control mode.

[0009] Preferably, adjusting the speed set value based on the actual operating speed to determine the current set value of the coiler includes: passing the actual operating speed and the speed set value through a speed adjustment algorithm to obtain an initial current set value; performing a speed limit adjustment on the initial current set value to determine the current set value of the coiler.

[0010] Preferably, performing a speed limit adjustment on the initial current set value to determine the current set value of the coiler includes: judging whether the initial current set value is within the range of the speed limit; if the initial current set value is greater than the upper limit of the speed limit, determining the upper limit of the speed limit as the current set value; if the initial current set value is less than the lower limit of the speed limit, determining the lower limit of the speed limit as the current set value; if the initial current set value is within the range of the speed limit, determining the initial output current value as the current set value.

[0011] Preferably, adjusting the current set value based on the actual output current to determine the actual torque value of the coiler includes: passing the actual output current and the current set value through a current adjustment algorithm to obtain an initial actual torque value; performing a current limit adjustment on the initial actual torque value to determine the actual torque value of the coiler.

[0012] Preferably, performing a current limit adjustment on the initial actual torque value to determine the actual torque value of the coiler includes: judging whether the initial actual torque value is within the range of the current limit; if the initial actual torque value is greater than the upper limit of the current limit, determining the upper limit of the current limit as the actual torque value; if the initial actual torque value is less than the lower limit of the current limit, determining the lower limit of the current limit as the actual torque value; if the initial actual torque value is within the range of the current limit, determining the initial actual torque value as the actual torque value.

[0013] Preferably, the method further includes: if it is detected that the strip is in a damaged state, controlling the coiler to be in the torque control mode.

[0014] In a second aspect, according to an embodiment of the present invention, the following technical solution is provided:

[0015] A coiler torque control device includes:

[0016] An acquisition module, configured to acquire the actual operating speed and the actual output current of the coiler if the coiler is in the speed control mode;

[0017] A current set value determination module, configured to adjust the speed set value based on the actual operating speed to determine the current set value of the coiler, where the speed set value is greater than the linear speed of the coiler;

[0018] An actual torque value determination module, configured to adjust the current set value based on the actual output current to determine the actual torque value of the coiler;

[0019] A first comparison module, configured to compare the actual torque value with the torque set value and select the smaller torque value as the target torque value;

[0020] A control module, configured to output the target torque value and control the coiler to execute the corresponding control mode according to the target torque value.

[0021] In a third aspect, according to an embodiment of the present invention, the following technical solution is provided:

[0022] An inverter includes: a memory, a processor, and a computer program stored on the memory and executable on the processor, and when the processor executes the program, the steps of the method according to any one of the foregoing first aspects are implemented.

[0023] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

[0024] The coiler torque control method provided by the embodiment of the present invention, if the coiler is in the speed control mode (which can be when receiving a signal to switch from the speed control mode to the torque control mode), by obtaining the actual operating speed of the coiler, adjusting the actual operating speed based on the speed set value, determining the actual output current of the coiler, then adjusting the actual output current according to the current set value, determining the actual torque value of the coiler, comparing the actual torque value with the received torque set value, judging the smaller value between the actual torque value and the torque set value, and taking the smaller value as the target torque value. Since the speed set value is higher than the line speed of the coiler, adjusting the speed set value with a higher speed based on the actual operating speed makes the speed deviation of the frequency converter always positive, so that the actual operating speed of the frequency converter gradually increases to the speed set value. During this process, the actual torque value is first less than the torque set value, and at this time the actual torque value is used as the target torque value until the actual torque value is greater than the torque set value, indicating that the coiler meets the requirement of being able to switch from the speed control mode to the torque control mode. At this time, the frequency converter controls the coiler to execute the torque control mode, which solves the problem of excessive torque fluctuation causing equipment vibration during the switching process from the speed control mode to the torque control mode, resulting in damage to the strip quality, and thus is beneficial to improving the torque output smoothness during the switching process and ensuring the quality of the strip and the stability of production. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0026] Figure 1 It is a flowchart of the coiler torque control method provided by the embodiment of the present invention;

[0027] Figure 2 It is a schematic diagram of the coiler torque control process provided by the embodiment of the present invention;

[0028] Figure 3 It is a schematic diagram of the structure of the coiler torque control device provided by the embodiment of the present invention;

[0029] Figure 4 It is a schematic diagram of the structure of the frequency converter provided by the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] The embodiments of the present application provide a coiler torque control method, device, and frequency converter, which can effectively solve the technical problem that the quality of the strip steel is damaged due to large torque output fluctuations during the switching process between the speed control and torque control of the coiler, and is beneficial to improving the torque output stability during the switching process.

[0031] The general idea of the technical solution of the embodiments of the present application is as follows:

[0032] A coiler torque control method is applied to a frequency converter, and the frequency converter is used to perform control switching between a speed control mode and a torque control mode of the coiler. The method includes: if the coiler is in the speed control mode, obtaining the actual operating speed and actual output current of the coiler; adjusting the speed set value based on the actual operating speed to determine the current set value of the coiler, where the speed set value is greater than the linear speed of the coiler; adjusting the current set value based on the actual output current to determine the actual torque value of the coiler; comparing the actual torque value with the torque set value, and selecting the smaller torque value as the target torque value; outputting the target torque value, and controlling the coiler to execute the corresponding control mode according to the target torque value.

[0033] To better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings of the specification and specific embodiments.

[0034] In a first aspect, a coiler torque control method provided by an embodiment of the present invention is applied to a frequency converter, and the frequency converter is used to perform control switching between a speed control mode and a torque control mode of the coiler. Specifically, as Figure 1 shown, the method includes the following steps S101 to step S105.

[0035] Step S101, if the coiler is in the speed control mode, obtaining the actual operating speed of the coiler;

[0036] Step S102, adjusting the speed set value based on the actual operating speed to determine the current set value of the coiler, where the speed set value is greater than the linear speed of the coiler;

[0037] Step S103, adjusting the current set value based on the actual output current to determine the actual torque value of the coiler;

[0038] Step S104, comparing the actual torque value with the torque set value, and selecting the smaller torque value as the target torque value;

[0039] Step S105, output the target torque value, and control the coiler to execute the corresponding control mode according to the target torque value.

[0040] It should be noted that the frequency converter provided in this application may include a speed regulator, a current regulator, and a comparator.

[0041] In a specific embodiment, when the coiler is in the speed control mode, or when the frequency converter controls the coiler to switch from the speed control mode to the torque control mode, the frequency converter needs to execute the step of obtaining the target torque value to control the coiler based on the target torque value.

[0042] Specifically, the frequency converter can obtain the actual operating speed of the coiler in real time. The actual operating speed can be detected by a speed measuring instrument in real time, compiled by a field speed encoder, and given by a programmable logic controller (PLC) connected to the frequency converter. Then, based on the speed set value and the actual operating speed, the current set value of the coiler is determined.

[0043] Among them, the speed set value is greater than the line speed of the coiler. Specifically, the setting range of the speed set value can be determined according to the on-site installation, equipment model, etc. For example, the speed set value can be 5% higher than the line speed.

[0044] In a specific embodiment, adjusting the actual operating speed based on the speed set value to determine the current set value of the coiler may specifically include: passing the actual operating speed and the speed set value through a speed adjustment algorithm to obtain an initial current set value; performing speed limit adjustment on the initial current set value to determine the current set value of the coiler.

[0045] Specifically, as Figure 2 shown, the speed regulator 101 in the frequency converter can perform PID adjustment on the speed set value and the actual operating speed to obtain the initial current set value. In order to prevent the output value (i.e., the initial current set value) of the speed regulator 101 from exceeding the specified range, speed limit 102 adjustment is performed on the initial current set value to determine the current set value of the coiler. The current set value is used as the input value of the current regulator 103.

[0046] Among them, the initial value of the current setting is adjusted by the speed limit 102 to determine the current setting value of the coiler, which may specifically include: determining whether the initial value of the current setting is within the range of the speed limit 102; if the initial value of the current setting is greater than the upper limit of the speed limit 102, then the upper limit of the speed limit 102 is determined as the current setting value; if the initial value of the current setting is less than the lower limit of the speed limit 102, then the lower limit of the speed limit 102 is determined as the current setting value; if the initial value of the current setting is within the range of the speed limit 102, then the initial value of the current setting is determined as the current setting value. Thus, the current setting value of the coiler is controlled within the threshold range set by the speed limit 102.

[0047] Among them, the speed limit 102 can be set through the internal parameters of the frequency converter according to the process requirements of the coiler, and the present application does not make specific limitations.

[0048] Next, based on the current regulator 103 in the frequency converter receiving the current setting value of the speed regulator 101, the actual torque value TRQ_REF of the coiler can be determined. In a specific embodiment, based on the current setting value, the actual output current is adjusted to determine the actual torque value TRQ_REF of the coiler, which may specifically include: passing the actual output current and the current setting value through a current adjustment algorithm to obtain the initial value of the actual torque; adjusting the initial value of the actual torque by the current limit 104 to determine the actual torque value TRQ_REF of the coiler.

[0049] Specifically, adjusting the initial value of the actual torque by the current limit 104 to determine the actual torque value TRQ_REF of the coiler includes: determining whether the initial value of the actual torque is within the range of the current limit 104; if the initial value of the actual torque is greater than the upper limit of the current limit 104, then the upper limit of the current limit 104 is determined as the actual torque value TRQ_REF; if the initial value of the actual torque is less than the lower limit of the current limit 104, then the lower limit of the current limit 104 is determined as the actual torque value TRQ_REF; if the initial value of the actual torque is within the range of the current limit 104, then the initial value of the actual torque is determined as the actual torque value TRQ_REF. Thus, the actual torque value TRQ_REF of the coiler is controlled within the threshold range set by the current limit 104.

[0050] Among them, the current limit 104 can be set through the internal parameters of the frequency converter according to the process requirements of the coiler, and the present application does not make specific limitations.

[0051] It should be noted that the actual output current can be obtained by conversion through the current transformer inside the frequency converter.

[0052] Such as Figure 2As shown, the current regulator 103 receives the current set value of the speed regulator 101 and the actual output current for PID regulation, and then determines the actual torque value TRQ_REF of the coiler through the current limiting 104.

[0053] In the torque mode of the coiler, the frequency converter receives the torque set value TENS_R1 sent by the PLC, and then compares the actual torque value TRQ_REF with the torque set value TENS_R1.

[0054] In a specific embodiment, before comparing the actual torque value TRQ_REF with the torque set value TENS_R1, torque limit regulation of the initial torque set value may also be included. Among them, the torque limit 105 can be set through the internal parameters of the frequency converter according to the process requirements of the coiler, and the present application does not make specific limitations.

[0055] Specifically, it is judged whether the initial torque set value is within the range of the torque limit 105; if the initial torque set value is greater than the upper limit of the torque limit 105, the upper limit of the torque limit 105 is determined as the torque set value TENS_R1; if the initial torque set value is less than the lower limit of the speed limit 102, the lower limit of the torque limit 105 is determined as the torque set value TENS_R1; if the initial torque set value is within the range of the speed limit 102, the initial torque set value is determined as the torque set value TENS_R1. Thus, the torque set value TENS_R1 of the coiler is controlled within the threshold range set by the torque limit 105.

[0056] Then, the comparator 106 in the frequency converter compares the actual torque value TRQ_REF with the torque set value TENS_R1, and selects the smaller torque value as the target torque value T_R. Specifically, if the actual torque value TRQ_REF is less than or equal to the torque set value TENS_R1, the actual torque value TRQ_REF is determined as the target torque value T_R; if the actual torque value TRQ_REF is greater than the torque set value TENS_R1, the torque set value TENS_R1 is determined as the target torque value T_R.

[0057] In a specific embodiment, after determining the target torque value T_R, the frequency converter outputs the target torque value T_R, and controls the coiler to execute the corresponding control mode according to the target torque value T_R. Specifically, controlling the coiler to execute the corresponding control mode according to the target torque value T_R may specifically include: if the actual torque value TRQ_REF is used as the target torque value T_R, controlling the coiler to execute the speed control mode; if the torque set value TENS_R1 is used as the target torque value T_R, controlling the coiler to switch from the speed control mode to the torque control mode.

[0058] Specifically, when the actual torque value TRQ_REF is less than or equal to the torque set value TENS_R1, the actual torque value TRQ_REF is output as the target torque value T_R, indicating that the current coiling site has not yet met the requirement of the execution torque set value TENS_R1, that is, it has not met the requirement of switching from the speed control mode to the torque control mode. Since the speed set value is greater than the line speed of the coiler, the speed deviation of the frequency converter remains positive, so the actual output current output by the speed regulator 101 of the frequency converter continues to increase, causing the actual torque value TRQ_REF to continue to increase until the actual torque value TRQ_REF is greater than the torque set value TENS_R1.

[0059] When the actual torque value TRQ_REF is greater than the torque set value TENS_R1, the torque set value TENS_R1 is output as the target torque value T_R. At this time, the actual torque meets the requirement of the torque set value TENS_R1, indicating that the coiling site meets the requirement of switching from the speed control mode to the torque control mode. At this time, when the coiler is switched from the speed control mode to the torque control mode, there is no torque fluctuation, thus solving the problem of torque fluctuation during the control mode switching process.

[0060] In a specific embodiment, after controlling the coiler to switch from the speed control mode to the torque control mode, it may further include: comparing the actual operating speed with the speed set value; if the actual operating speed is greater than or equal to the speed set value, controlling the coiler to switch from the torque control mode to the speed control mode.

[0061] Specifically, when the actual operating speed increases to 5% higher than the line speed of the coiler, the saturation state of the speed regulator 101 is cancelled, causing the current set value to gradually decrease, and the actual torque value TRQ_REF to gradually decrease accordingly. Furthermore, the actual torque value TRQ_REF begins to be less than or equal to the torque set value TENS_R1. At this time, the coiler switches to the speed control mode, realizing the switching of the coiler between the speed control mode and the torque control mode.

[0062] Furthermore, in order to effectively avoid abnormal operation of the equipment, the coiler torque control method provided by this application may further include: if it is detected that the strip is in a damaged state, controlling the coiler to be in the torque control mode.

[0063] Specifically, after the strip enters the coiler, it is detected whether the strip is in a damaged state. If so, the coiler is controlled to be in the torque control mode, thereby avoiding situations such as the damaged strip being damaged again under the speed control mode and causing equipment damage. Among them, the damaged state may refer to states such as strip breakage and strip cracking.

[0064] In this way, even if the strip breaks during the actual production process, the equipment still continues to operate in torque control, and at this time, the motor accelerates.

[0065] Therefore, when the coiler switches from the speed control mode to the torque control mode, the frequency converter converts the speed set value received, which is 5% higher than the line speed, and the actual operating speed through the speed regulator 101 into a current set value. The current set value and the actual output current are converted into the actual torque value TRQ_REF through the current regulator 103. When the coiler is in the torque control mode, the torque set value TENS_R1 received by the frequency converter is compared with the actual torque value TRQ_REF, and the smaller torque value is determined as the target torque value T_R of the frequency converter, so as to achieve the smoothness of the torque value during the switching process of the coiler from the speed control mode to the torque control mode and ensure the strip quality.

[0066] In summary, through a coiler torque control method provided by an embodiment of the present invention, the technical problem that the strip quality is damaged due to large torque output fluctuations during the switching process between the speed control and torque control of the coiler can be effectively solved, which is beneficial to improving the smoothness of torque output during the switching process. This method can effectively participate in the adjustment of torque control to ensure the strip quality and production stability.

[0067] In a second aspect, based on the same inventive concept, this embodiment provides a coiler torque control device, as Figure 3 shown, including:

[0068] An acquisition module 301, configured to obtain the actual operating speed and the actual output current of the coiler if the coiler is in the speed control mode;

[0069] A current set value determination module 302, configured to adjust the speed set value based on the actual operating speed to determine the current set value of the coiler, where the speed set value is greater than the line speed of the coiler;

[0070] An actual torque value determination module 303, configured to adjust the current set value based on the actual output current to determine the actual torque value of the coiler;

[0071] A first comparison module 304, configured to compare the actual torque value with the torque set value and select the smaller torque value as the target torque value;

[0072] A control module 305, configured to output the target torque value and control the coiler to execute the corresponding control mode according to the target torque value.

[0073] As an alternative embodiment, the control module 305 is specifically configured to: if the actual torque value is used as the target torque value, control the coiler to execute the speed control mode; if the torque set value is used as the target torque value, control the coiler to switch from the speed control mode to the torque control mode.

[0074] As an alternative embodiment, the device further includes:

[0075] A second comparison module, configured to compare the actual operating speed with the speed set value; if the actual operating speed is greater than or equal to the speed set value, control the coiler to switch from the torque control mode to the speed control mode.

[0076] As an alternative embodiment, the current set value determination module 302 includes:

[0077] A speed adjustment sub-module, configured to obtain an initial current set value by performing a speed adjustment algorithm on the actual operating speed and the speed set value;

[0078] A speed limit adjustment sub-module, configured to perform a speed limit adjustment on the initial current set value to determine the current set value of the coiler.

[0079] As an alternative embodiment, the speed limit adjustment sub-module is specifically configured to: determine whether the initial current set value is within the speed limit range; if the initial current set value is greater than the upper limit of the speed limit, determine the upper limit of the speed limit as the current set value; if the initial current set value is less than the lower limit of the speed limit, determine the lower limit of the speed limit as the current set value; if the initial current set value is within the speed limit range, determine the initial output current value as the current set value.

[0080] As an alternative embodiment, the actual torque value determination module 303 includes:

[0081] A current adjustment sub-module, configured to obtain an initial actual torque value by performing a current adjustment algorithm on the actual output current and the current set value;

[0082] A current limit adjustment sub-module, configured to perform a current limit adjustment on the initial actual torque value to determine the actual torque value of the coiler.

[0083] As an alternative embodiment, the current limit adjustment sub-module is specifically configured to: determine whether the initial value of the actual torque is within the range of the current limit; if the initial value of the actual torque is greater than the upper limit of the current limit, then determine the upper limit of the current limit as the actual torque value; if the initial value of the actual torque is less than the lower limit of the current limit, then determine the lower limit of the current limit as the actual torque value; if the initial value of the actual torque is within the range of the current limit, then determine the initial value of the actual torque as the actual torque value.

[0084] As an alternative embodiment, the device further includes:

[0085] A strip abnormality detection module, configured to control the coiler to be in the torque control mode if it detects that the strip is in a damaged state.

[0086] Each of the above modules may be implemented by software code. In this case, the above modules may be stored in the memory of the control device. Each of the above modules may also be implemented by hardware, such as an integrated circuit chip.

[0087] The coiler torque control device provided by the embodiment of the present invention has the same implementation principle and the same technical effects as those of the foregoing method embodiment. For a brief description, for the parts not mentioned in the device embodiment, reference may be made to the corresponding content in the foregoing method embodiment.

[0088] In a third aspect, based on the same inventive concept, this embodiment provides an inverter 500, as Figure 4 shown, including: a memory 501, a processor 502, and a computer program 503 stored on the memory and executable on the processor. When the processor 501 executes the program, it implements the steps of the coiler torque control method described in the foregoing first aspect.

[0089] Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications once they learn the basic creative concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications falling within the scope of the present invention.

[0090] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. A coiler torque control method, characterized in that, Applied to an inverter, the inverter is used to perform control switching between a speed control mode and a torque control mode for a coiler, and the method includes: If the coiler is in the speed control mode, obtain the actual operating speed and the actual output current of the coiler; Adjust the speed set value based on the actual operating speed to determine the current set value of the coiler, where the speed set value is greater than the linear speed of the coiler; Adjust the current set value based on the actual output current to determine the actual torque value of the coiler; Compare the actual torque value with the torque set value, and select the smaller torque value as the target torque value; Output the target torque value, and control the coiler to execute the corresponding control mode according to the target torque value; The adjusting the speed set value based on the actual operating speed to determine the current set value of the coiler includes: passing the actual operating speed and the speed set value through a speed adjustment algorithm to obtain an initial current set value; performing speed limit adjustment on the initial current set value to determine the current set value of the coiler; Adjusting the current set value based on the actual output current to determine the actual torque value of the coiler includes: passing the actual output current and the current set value through a current adjustment algorithm to obtain an initial actual torque value; performing current limit adjustment on the initial actual torque value to determine the actual torque value of the coiler.

2. The method according to claim 1, characterized in that The controlling the coiler to execute the corresponding control mode according to the target torque value includes: If the actual torque value is used as the target torque value, control the coiler to execute the speed control mode; If the torque set value is used as the target torque value, control the coiler to switch from the speed control mode to the torque control mode.

3. The method according to claim 2, wherein After the controlling the coiler to switch from the speed control mode to the torque control mode, the method further includes: Comparing the actual operating speed with the speed set value; If the actual operating speed is greater than or equal to the speed set value, control the coiler to switch from the torque control mode to the speed control mode.

4. The method according to claim 1, wherein The performing speed limit adjustment on the initial current set value to determine the current set value of the coiler includes: Judging whether the initial current set value is within the speed limit range; If the initial current set value is greater than the upper limit of the speed limit, determine the upper limit of the speed limit as the current set value; If the initial current set value is less than the lower limit of the speed limit, determine the lower limit of the speed limit as the current set value; If the initial current set value is within the speed limit range, determine the initial output current value as the current set value.

5. The method according to claim 1, wherein The performing current limit adjustment on the initial actual torque value to determine the actual torque value of the coiler includes: Judging whether the initial actual torque value is within the current limit range; If the initial actual torque value is greater than the upper limit of the current limit, determine the upper limit of the current limit as the actual torque value; If the initial value of the actual torque is less than the lower limit of the current limit, the lower limit of the current limit is determined as the actual torque value; If the initial value of the actual torque is within the range of the current limit, the initial value of the actual torque is determined as the actual torque value.

6. The method according to claim 1, wherein It further includes: If it is detected that the strip is in a damaged state, the coiler is controlled to be in the torque control mode.

7. A coiler torque control device, characterized in that, It includes: An acquisition module, configured to acquire the actual operating speed and the actual output current of the coiler if the coiler is in the speed control mode; A current set value determination module, configured to adjust the speed set value based on the actual operating speed to determine the current set value of the coiler, where the speed set value is greater than the linear speed of the coiler; An actual torque value determination module, configured to adjust the current set value based on the actual output current to determine the actual torque value of the coiler; A first comparison module, configured to compare the actual torque value with the torque set value and select the smaller torque value as the target torque value; A control module, configured to output the target torque value and control the coiler to execute the corresponding control mode according to the target torque value; The current set value determination module is configured to obtain an initial current set value by passing the actual operating speed and the speed set value through a speed adjustment algorithm; perform speed limit adjustment on the initial current set value to determine the current set value of the coiler; The actual torque value determination module is configured to obtain an initial actual torque value by passing the actual output current and the current set value through a current adjustment algorithm; perform current limit adjustment on the initial actual torque value to determine the actual torque value of the coiler.

8. A frequency converter, characterized in that, It includes: A memory, a processor, and a computer program stored on the memory and executable on the processor, and when the processor executes the program, the steps of the method according to any one of claims 1-6 are implemented.

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