JPH0119600Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a speed compensation control device for a rolling mill that suppresses speed fluctuations caused by impact loads on the rolling mill.

[Technical issues of invention]

In a metal rolling mill where rolling rolls are driven by an electric motor, when the rolled material is bitten by the rolls, an impact load as shown at T in Figure 1 is applied, but due to the delay in the speed control system, the motor current I is The rolling mill speed v also drops instantaneously as shown in the figure.
t indicates the time axis.

The magnitude and time of the impact speed drop at this time are determined by the moment of inertia of the electric motor including the rolling roll, the load torque, and the response speed of the speed control system.

Speeding up the response of the speed control system will reduce the drop in impact speed, but if the response frequency approaches the torsional vibration frequency of the machine shaft, there will be problems such as instability in the control system, so there are limitations to speeding up the speed response. Therefore, there was a limit to reducing the impact velocity drop.

[Purpose of invention]

The object of the present invention is to provide a speed compensation control device for a rolling mill that detects the rolling torque of the rolling mill and adds it to the speed control system as a compensation input, thereby reducing the instantaneous speed drop during impact loading. It is said that

[Summary of the idea]

The present invention includes a rolling torque calculation circuit that detects the rolling pressure of a rolling mill and calculates the required rolling torque, and a rolling current calculation circuit that calculates the required rolling current from this rolling torque and motor field current. This is a speed compensation control device for a rolling mill that adds the current reference value to the current reference value in the speed control of the rolling motor, thereby suppressing instantaneous speed drops due to impact loads prior to speed control.

[Example of idea]

An embodiment of the present invention is shown in FIG.

In FIG. 3, a rolled material 1 is rolled by a rolling roll, and the rolling force is detected by a load cell 10.

The driving DC motor 3 is energized by a thyristor power source 4, and the motor field 5 is energized by a thyristor field power source 6. The rolling mill speed v, motor current I, and field current If are detected by a speed detector 7, a current detector 8, and a field current detector 9, respectively.

During no-load operation, the speed reference signal v ₀ and the detected speed v are compared and amplified by the speed control amplifier 11, and the output
I _M becomes the current reference, and the detected current I is compared and amplified by the current control amplifier 13 via the current limit amplifier 12, and its output controls the firing phase of the thyristor power supply 4 to speed up the motor 3. is controlled.

When the rolled material 1 is passed through the roll 2, the rolling force F generated on the rolling roll is detected via the load cell 10 and the rolling force calibrator 14, and further converted into rolling torque T via the rolling torque calculation circuit 15. be done.

On the other hand, the motor field current If is the field magnetic flux correction circuit 17
It is converted into field magnetic flux Φ via .

The rolling current calculation circuit 16 inputs the rolling torque T and the field magnetic flux Φ and calculates T÷Φ.
Calculate the rolling current I _O.

This rolling current I _O is added to the aforementioned motor current reference I _M in the current limiting amplifier 12, and I _M +I _O becomes the current reference to control the motor current I.

The rolling torque signal T is detected by the load cell 10 at the same time as the sheet is passed, and the current reference of the current control amplifier 13 is immediately corrected, so that the speed drop due to the impact load is compensated for in advance. As shown at I and v in the figure, the current immediately rises, and the instantaneous speed drop is greatly reduced in both magnitude and time.

[Effect of idea]

As explained above, according to the present invention, the rolling mill detects the rolling force of the rolling mill and adds this as a compensation signal to speed control, thereby reducing the instantaneous speed drop due to impact load during sheet threading. A speed compensation control circuit is obtained.

[Brief explanation of the drawing]

Fig. 1 is a time chart showing an example of speed fluctuation under conventional impact load, Fig. 2 is a time chart showing improvement of speed fluctuation according to the present invention, and Fig. 3 is a time chart showing an example of speed fluctuation control device for a rolling mill according to the present invention. It is a system diagram showing one example. 3...Rolling motor, 4...Thyristor power supply, 6
...Thyristor field power supply, 7...Speed detector, 8
...Current detector, 9...Field current detector, 10...
...Load cell, 11...Speed control amplifier, 12...
...Current limiting amplifier, 13...Current control amplifier,
14... Rolling force calibrator, 15... Rolling torque calculation circuit, 16... Rolling current calculation circuit, 17... Field magnetic flux correction circuit.

Claims (1)

[Scope of utility model registration request] A rolling torque calculation circuit that detects the rolling pressure of the rolling mill and calculates the required rolling torque, and a rolling current calculation circuit that calculates the required rolling current from the above-mentioned required rolling torque and motor field current. A speed compensation control device for a rolling mill, characterized in that it is added to a current reference value in speed control of an electric motor.