Helper roll controlling system

Abstract

To provide a helper roll controlling system capable of preventing an excessive Droop amount correction amount from being calculated at the time of steady operation.SOLUTION: A controlling system comprises: an actual load torque computing unit for calculating an actual load torque of a motor for driving a helper roll; a Droop gain computing unit for calculating a Droop gain using the actual load torque; a Droop amount correction amount computing unit for calculating a Droop amount correction amount using the Droop gain; and a motor current / voltage computing unit for calculating current and voltage for controlling the motor so that the Droop amount correction amount follows an added rotational speed reference. The actual load torque computing unit includes a mechanical loss torque acquisition unit for acquiring a mechanical loss torque and is configured to calculate the actual load torque by subtracting the mechanical loss torque acquired by the mechanical loss torque acquisition unit from a motor torque at the time of steady operation.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a helper roll control system that controls the amount of droop of a helper roll. [Background technology]

[0002] This type of helper roll control system is known from Patent Document 1. In this control system, a droop amount compensation amount (hereinafter also referred to as "droop amount correction amount") is calculated from the droop amount and motor current during acceleration / deceleration, and the calculated droop amount compensation amount is added to the rotational speed reference and input to the speed controller of the helper roll controller. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-344405 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the technique described in Patent Document 1, when calculating the droop compensation amount, acceleration / deceleration torque is taken into consideration but mechanical loss torque is not, so the mechanical loss torque is included in the load torque during steady operation. As a result, an excessive droop compensation amount is calculated, and as shown in Figure 5, when the droop function (a function that provides a drooping characteristic in which the rotational speed decreases as the motor current increases) is set, the rotational speed reference is reduced by the amount of the excessive droop compensation amount. This increases the deviation between the speed reference and the actual speed, causing the motor to become overloaded, which may ultimately cause unstable operation of a rolling line equipped with helper rolls.

[0005] Therefore, an object of the present disclosure is to provide a helper roll control system that can prevent an excessive droop amount correction amount from being calculated during steady operation. [Means for solving the problem]

[0006] A first aspect of the present disclosure relates to a helper roll control system that controls the droop amount of helper rolls that are installed in a rolling line and that thread rolled material. The control system includes an actual load torque calculation unit that calculates an actual load torque of a motor that drives the helper roll, a droop gain calculation unit that calculates a droop gain using the actual load torque, a droop amount correction amount calculation unit that calculates a droop amount correction amount using the droop gain, and a motor current / voltage calculation unit that calculates a current and a voltage for controlling the motor so that it follows a rotational speed reference to which the droop amount correction amount has been added. The actual load torque calculation unit has a mechanical loss torque acquisition unit that acquires mechanical loss torque, and is configured to calculate the actual load torque by subtracting the mechanical loss torque acquired by the mechanical loss torque acquisition unit from the motor torque during steady operation.

[0007] The second aspect has the following characteristics in addition to the first aspect: The Droop gain calculation unit has a limiter that limits the calculated Droop gain to a predetermined upper limit value. [Effects of the Invention]

[0008] According to the present disclosure, the actual load torque is calculated taking into account the mechanical loss torque, and the calculated actual load torque is used to determine the droop gain and therefore the droop correction amount. This prevents an excessive droop correction amount from being calculated during steady operation, and even if the droop correction amount is added, the rotational speed reference does not decrease and the motor does not become overloaded. Therefore, rolled material can be threaded stably in a rolling line equipped with helper rolls. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a block diagram showing an example of the configuration of a control system for a helper role according to an embodiment. [Figure 2] 2 is a diagram illustrating a calculation process of an actual load torque calculation unit shown in FIG. 1. [Figure 3] 2 is a diagram illustrating a calculation process of a Droop gain calculation unit shown in FIG. 1. FIG. [Figure 4] FIG. 2 is a diagram illustrating an example of a hardware configuration of a main control device. [Figure 5] 10A and 10B are schematic diagrams showing rotation speed standards when the Droop function is set and when the Droop function is not set, respectively. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, with reference to the drawings, a helper roll control system according to an embodiment will be described, taking as an example a case where the droop amount of a helper roll that is installed in a rolling line and that passes a rolled material through is controlled. Common or corresponding elements in each drawing are given the same reference numerals, and their explanation will be simplified or omitted.

[0011] Fig. 1 is a block diagram showing an example of the configuration of a control system 1 for a helper roll Hr according to an embodiment. Fig. 2 is a diagram showing the calculation logic of an actual load torque calculation unit 21 shown in Fig. 1. Fig. 3 is a diagram showing the calculation logic of a Droop gain calculation unit 22 shown in Fig. 1.

[0012] As shown in Fig. 1, the control system 1 for the helper roll Hr includes a master controller 2 and a drive device 3. The master controller 2 and the drive device 3 are capable of communicating with each other via wire or wirelessly. The control system 1 controls the droop amount of at least one helper roll Hr (one in the example shown in Fig. 1) driven by a motor 4.

[0013] The main control device 2 includes an actual load torque calculation unit 21, a droop gain calculation unit 22, and a rotational speed reference calculation unit 23. The drive device 3 includes a motor torque / acceleration / deceleration torque calculation unit 31, a droop amount correction amount calculation unit 32, a motor current / voltage calculation unit 33, and a current detection unit 34.

[0014] The actual load torque calculation unit 21 calculates the motor torque T MOT and acceleration / deceleration torque T acc In addition to the mechanical loss torque T mech Furthermore, the actual load torque T act That is, the actual load torque calculation unit 21 calculates the motor torque T MOT Acceleration / deceleration torque T acc and mechanical loss torque T mech By subtracting from the actual load torque T act Therefore, the actual load torque T act is the mechanical loss torque T during steady operation mech is taken into consideration (subtracted). T act =T MOT -T acc -T mech ···(1)

[0015] Motor torque T MOT and acceleration / deceleration torque T acc is input from the motor torque / acceleration / deceleration torque calculation unit 31.

[0016] As shown in Fig. 2, the actual load torque calculation unit 21 has a mechanical loss torque acquisition unit 211 and a subtractor 212. The mechanical loss torque acquisition unit 211 has a mechanical loss torque table TBm that is obtained in advance by experiment or simulation. The mechanical loss torque table TBm specifies the mechanical loss torque in each speed range. The mechanical loss torque acquisition unit 211 refers to the mechanical loss torque table TBm and calculates the actual speed N (actual speed N) input from the rotation speed detection means 41 (described later). FBK The subtractor 212 calculates the actual load torque T act and calculate the actual load torque T act to the Droop gain calculation unit 22. Note that the mechanical loss torque acquisition unit 211 can also calculate the mechanical loss torque according to the actual speed performance using a mathematical formula instead of the mechanical loss torque table TBm.

[0017] The droop gain calculation unit 22 has multipliers 221 and 222 and a limiter 223. The multiplier 221 calculates the actual load torque T act and the preset semi-fixed Droop gain upper limit G HL Using the above, the Droop gain G is calculated using the following equation (2). a That is, the multiplier 221 calculates the actual load torque T act Droop gain upper limit G HL By multiplying by a Ask for. G a =T act ×G HL ···(2)

[0018] Here, the actual speed N of motor 4 may be decreased due to external factors such as breakage of the rolled material (plate breakage). FBK may become large. Actual speed N FBK is detected by the rotation speed detection means 41 attached to the motor 4. In this case, the actual speed N FBK The deviation between the speed reference and the motor torque T MOT This increases the actual load torque T act becomes excessively large, and a situation may occur in which the motor 4 accelerates even though it is desired to stop the motor 4.

[0019] Therefore, the multiplier 222 sets the upper limit value G HL The overload factor F of motor 4 OL By multiplying this, the upper limit G HL and calculate the upper limit G HL The limiter 223 outputs the Droop gain G a and the upper limit value G input from the multiplier 222 HL Then, compare the Droop gain G a is the upper limit G HL In the following cases, the limiter 223 reduces the Droop gain G a Final Droop Gain G Dto the droop amount correction amount calculation unit 32. On the other hand, the droop gain G a is the upper limit G HL If the upper limit G HL Final Droop Gain G D to the droop amount correction amount calculation unit 32. In this way, the limiter 223 limits the droop gain G D is the upper limit G HL It is limited to the following:

[0020] The rotational speed reference calculation unit 23 calculates the rotational speed reference N of the motor 4 that rotates the roll Hr based on the threading speed of the rolled material input from the outside. S Calculate the calculated rotation speed reference N S is output to the drive device 3. The output rotation speed reference N S A droop amount correction amount calculated by a droop amount correction amount calculation unit 32 (to be described later) is added to the above.

[0021] The motor torque / acceleration / deceleration torque calculation unit 31 calculates the motor torque T from the torque current input from the current detection unit 34. MOT and outputs it to the actual load torque calculation unit 21. Also, the motor torque / acceleration / deceleration torque calculation unit 31 calculates the actual speed N FBK and the moment of inertia GD, which is set as a parameter of motor 4. 2 and [kg m 2 ], and the acceleration / deceleration torque T acc is calculated and output to the actual load torque calculation unit 21. In the following equation (3), N TOP is the motor rated speed. T acc =(dN FBK / dt)×N TOP ×GD2···(3)

[0022] The droop amount correction amount calculation unit 32 calculates the droop gain G DThe speed droop amount corresponding to the current is calculated as the droop amount correction amount based on the torque current input from the current detection unit 34. The calculated droop amount correction amount is calculated based on the mechanical loss torque T mech Droop gain G calculated taking into account D Since it is calculated using the mechanical loss torque T mech These factors were taken into consideration.

[0023] The droop amount correction amount (speed droop amount) calculated by the droop amount correction amount calculation unit 32 is calculated based on the rotation speed reference N s After being added to the motor current / voltage calculation unit 33, the calculated value is input to the motor current / voltage calculation unit 33.

[0024] The motor current / voltage calculation unit 33 calculates the reference rotation speed to which the droop amount correction amount has been added and the actual speed N of the motor 4. FBK Based on this, a current reference and a voltage reference for controlling the motor 4 so as to follow the rotation speed reference to which the droop amount correction amount has been added are calculated, and output to the motor 4.

[0025] The current detection unit 34 detects the total current input to the motor 4 connected to the helper roll Hr, calculates the torque current from the detected total current, and outputs the calculated torque current to the motor torque / acceleration / deceleration torque calculation unit 31 and the droop amount correction amount calculation unit 32.

[0026] The specific structures of the main control device 2 and the drive devices 3 are not limited, but may be as follows, for example. FIG. 4 is a diagram showing an example of the hardware configuration of the main control device 2 and the drive devices 3. The functions of each part of the main control device 2 and the drive devices 3 can be realized by the processing circuit 10 shown in FIG. 4. The processing circuit 10 may be dedicated hardware 10a. The processing circuit may include a processor 10b and a memory 10c. The processing circuit may be partially formed as dedicated hardware 10a and further include a processor 10b and a memory 10c. In the example of FIG. 4, a portion of the processing circuit 10 is formed as dedicated hardware 10a, and the processing circuit 10 also includes a processor 10b and a memory 10c. At least a portion of the processing circuit 10 may be at least one dedicated hardware 10a. In this case, the processing circuit may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, or a combination thereof. The processing circuit may include at least one processor 10b and at least one memory 10c. In this case, each function of the main control device 2 and the drive device 3 is realized by software, firmware, or a combination of software and firmware. The software and firmware are written as programs and stored in memory 10c. The processor 10b realizes the functions of each part of the main control device 2 and the drive device 3 by reading and executing the programs stored in memory 10c. The processor 10b is also called a CPU (Central Processing Unit), central processing unit, processing device, arithmetic unit, microprocessor, microcomputer, or DSP. The memory 10c corresponds to, for example, non-volatile or volatile semiconductor memory such as RAM, ROM, flash memory, EPROM, and EEPROM. In this way, the processing circuit can realize each function of the main control device 2 and the drive device 3 by hardware, software, firmware, or a combination of these.

[0027] As described above, in this embodiment, the mechanical loss torque T mech Considering the actual load torque T act is calculated, and the calculated actual load torque T act Using the Droop Gain G D Consequently, the droop amount correction amount is calculated. This makes it possible to prevent an excessive droop amount correction amount from being calculated during steady operation, and even if the droop amount correction amount is added, the rotation speed reference will not decrease and the motor 4 will not be overloaded. Therefore, the rolled material can be stably threaded in a rolling line provided with helper rolls Hr.

[0028] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments and can be modified in various ways without departing from the spirit of the present disclosure. In the above-described embodiments, the motor torque / acceleration / deceleration torque calculation unit 31 and the droop amount correction amount calculation unit 32 are provided in the drive device 3, but they may also be provided in the master control device 2. [Explanation of symbols]

[0029] 1...Helper roll control system, 2...Main control device, 21...Actual load torque calculation unit, 22...Droop gain calculation unit, 23...Rotational speed reference calculation unit, 3...Drive device, 31...Motor torque / acceleration / deceleration torque calculation unit, 32...Droop amount correction amount calculation unit, 33...Motor current / voltage calculation unit, 34...Current detection unit, 4...Motor, Hr...Helper roll

Claims

1. A helper roll control system that is installed in a rolling line and controls the droop amount of a helper roll for threading a rolled material, an actual load torque calculation unit that calculates an actual load torque of a motor that drives the helper roll; a droop gain calculation unit that calculates a droop gain using the actual load torque; a droop amount correction amount calculation unit that calculates a droop amount correction amount using the droop gain; a motor current / voltage calculation unit that calculates a current and a voltage for controlling the motor so that the motor follows the rotation speed reference to which the droop amount correction amount has been added, The actual load torque calculation unit has a mechanical loss torque acquisition unit that acquires a mechanical loss torque, and calculates the actual load torque by subtracting the mechanical loss torque acquired by the mechanical loss torque acquisition unit from the motor torque during steady operation.

2. The helper roll control system according to claim 1 , wherein the Droop gain calculation unit has a limiter that limits the calculated Droop gain to a predetermined upper limit value.

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