SU1690231A1 - Regulator of electric condition of ore-smelting furnace - Google Patents

Abstract

The invention relates to electrical engineering. The purpose of the invention is to increase the productivity of the furnace by improving the quality of control. The introduction of a logic control loop for voltage, depending on the signals D iD, provides. vaet higher speed regul; torus in comparison with the known regulators yoami 1 silt,

Description

The invention relates to electrothermal, more specifically, to automatic regulators of the electric mode of ore-thermal electric furnaces.

The purpose of the invention is to increase the productivity of the furnace by improving the quality of control.

The drawing shows a block diagram of a regulator of the electric mode of the ore-thermal furnace.

In the flowchart, current sensor 2 and voltage sensor 3 are connected to the ore-thermal furnace 1, the current output of sensor 2 is connected to the input of the first threshold comparison unit 4, the second input of which is connected to the output of the first task unit 5, and the first output to the first the input of the first operational amplifier 6. The output of the amplifier 6 through the current regulator 7 is connected to the input of the actuator 8 actuator 8, the output of the voltage sensor 3 is connected to the first input of the first comparison unit 9, the second input of which is connected

with the output of the second task unit 10, and the output through the first filter 11 with the first input of the first adder 12. The second input of the adder 12 is connected to the first output of the block of operational amplifiers 13 correction The input of the block 13 is connected to the output of the subtractor 14, the second input of which is connected with the second output of the first threshold flask 4 comparisons. The first output of the first adder 12 is connected via the second filter 15 to the first input of the second adder 16, the second output to the first input of the second threshold comparison block 17, and the third output to the first input of the second operational amplifier 18. The second input of the second adder 16 is connected to the second output block operational amplifiers 13 correction. The first output of the second adder 16 is connected via the third filter 19 to the second input of the subtraction unit 14, the second output to the first input of the third threshold unit 20, and the third output to the second input of the second operational amplifier

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18. The output of the second operational amplifier 18 is connected to the first input of the second comparison unit .21, the second input of which is connected to the third output of the first threshold comparison unit 4, and the output to the second input of the first operational amplifier 6. The second input of the second threshold comparison unit 17 connected to the output of the third task unit 22, and the output to the first input of the third adder 23. The second input of the third threshold unit 20 is connected to the output of the fourth task set 24, and the output to the second input of the third adder 23, the output of which is connected swing regulator switch 25 voltage levels.

The ore-smelting furnace is a dynamic object. Its transfer function is a third-order inertial aperiodic link. The inertia of the drives, measurement circuits, and a short network can be ignored due to the smallness of the corresponding constant electric-time. Then the transfer function of the furnace can be represented as follows:

TO

W (p)

(D

U1P + 1J (T2P + W3P + 1)

where K is the current gain factor, kA / V;

TI, Ta, Tz-constant of the furnace time, s, Control of the electric mode of the ore-thermal furnace only on the output variable (on the electrode current) does not provide the required control quality, due to the lack of information about the furnace dynamics, i.e. on signals proportional to the first and second derivatives with respect to the current of the electrode from a given (reference) value. These signals can be singled out, without resorting to time differentiation of the deviation of the electrode current, which is a difficult task to accomplish. To do this, it is sufficient to implement the transfer function (1) in the form of three aperiodic links of the first order, for example, as a series connection of three RC or RL filters with time constants equal to the time constant of the furnace TI, T2, Tz. By choosing the appropriate nominal values of the passive elements of each of the filters, the transfer function of the furnace can be accurately implemented (1). The input signal for the filters is an electrical control signal for switching the voltage steps of the furnace transformer. The filter output signal is the predicted value of the current deviation of the electrode L Ave. To

signals proportional to the first and second derivatives of the electrode current deviation from the setpoint, obtained from the filter outputs, corresponded to the actual parameters of the furnace under the action of disturbances, the device determines the difference between the measured electrode current deviation А I and predicted by the filter block the deviation Л П, t . ev

0 DI-1 1pr.

A signal proportional to the difference Ј contains information about disturbances in the furnace. This signal is added to the adders. As a result of this operation, the weekend

5, the signals from the adders turn out to be proportional to the signals of the first and second derivatives with respect to the current deviation, i.e., I I and D i.

The electrical mode regulator works as follows. If the electrode current e is in a predetermined range of nominal values, the control system performs perturbations similarly to the APP-1 type of controllers. In this case, the error signal on the current D1 1E - zed. is fed to the input of the operational amplifier 6, where it is amplified in power, and then fed to the current regulator 7. This regulator moves the furnace electrode to one or another

0 side, depending on the sign I,. The movement of the electrode is carried out in order to compensate for DI by acting on the electrode of the actuator of the movement of the electrode 8.

5 In this case, if the current deviation DI has the highest derivatives of DI and ID I, not falling outside the limits N1, N2, there is no control signal for voltage correction at the output of the third adder 23.

0 Electrical signals proportional to D l and D are formed at the outputs of the first 12 and second 16 adders. Since DI deviations are insignificant, then the output of the filters, in particular filter 19, is the predicted current deviation signal. differs from the measured D value slightly.

Difference of deviations Ј D1-D 1Pr.

and from the subtraction unit 14 enters the first and second adders 12 and 16. The scaling of the signals Ј for each of the channels is selected based on the requirement that the voltage correction circuit is stable. From the subtraction unit 14, a low level electrical signal is supplied. Accordingly, the low level signal is also removed from the adders 12 and 16, the second and third threshold blocks 17 and 20 of the comparison

five

do not work, and the initiative signal to the voltage level regulator 25 is not received. Similar signals are also not received at the current regulator 6, since the prohibition signal is received from the first matching block 21 from the first threshold comparison unit 4.

If the disturbance is of considerable magnitude, or its intensity is significant, then in a conventional regulator it takes considerable time to compensate for it. This controller in this case works as follows.

When And I L 13ad. the first threshold comparison unit 4 is triggered, which, with its output signal, triggers a block 21 of coincidence. In this case, an adjustable signal A o, proportional to the sum:

Alo Ki D1 + K2D l + KZD

where Ki, K2, Kz are the scale factors of operational amplifiers b and 18 along the corresponding current channels;

And I, D Iy are electrical signals proportional to the first and second derivatives by the deviation of the electrode current.

A signal (generated at the output of the adder 16, and a signal A I1 at the output of the adder 12.

Thus, under the action of high-level perturbations, the variable parameter is the signal A 0. Therefore, the current regulator 7 and, accordingly, the actuating mechanism of the electrode electrode 8 react to a signal of a higher level than the signal KiA I.

. Simultaneously with the compensation of current disturbances, voltage compensation is performed. If the signals A1 and A r1 exceed the permissible levels, the second and third threshold blocks 17, 20 of the comparison (or one of them depending on the level of A I and AI) are triggered. The output of the adder 23 generates a control signal for resetting or increasing the supply voltage using the voltage regulator 25 for switching the voltage of the furnace transformer, and the number of voltage levels or ± AU is selected depending on the level of the initiative signal from the third adder 23 s the purpose of compensation is A t0.

Thus, the inclusion of a logic control loop for voltage depending on the signals D and AI provides a higher speed controller than the known ones, and the regulation by a generalized parameter

D10 provides higher quality (minimum regulation error).

Claims (1)

The invention The regulator of the electric mode of the ore-no-furnace furnace contains a current sensor, the output of which is connected to the first input of the first threshold comparison unit, the second input of which is connected to the output of the first task unit, and the first output - with the first input of the first operational amplifier, the output of which through the current regulator is connected to the input-actuator of the electrode movement, voltage sensor, the output of which is connected to the first input of the first comparison unit, the second input of which is connected to the output of the second task unit, and regulator switching voltage steps, characterized in that, in order to increase the productivity of the furnace by improving the quality of control, it additionally contains the third and fourth blocks of the task, three filters, three adders, W The operational amplifier, the second comparison unit, the second and third comparison threshold units, the correctional operational amplifier unit and the subtraction unit, the first input of which is connected to the second output of the first threshold comparison unit, and the output to the input of the correction amplifier unit, the output of the first comparison unit through the first filter is connected to the first input of the first adder, the second input of which is connected to the first output of the block of operational correction amplifiers, the first output of the first adder is connected via the second filter with the first input of the second adder, the second output with the first input of the second threshold comparison unit, and the third output - with the first input of the second operational amplifier, the second input of the second adder is connected to the second output of the block of operational correction amplifiers, the first output of the second adder via the third filter is connected to the second input of the subtraction unit, the second output to the first input of the third threshold comparison unit, and the third output - with the second input of the second operational amplifier, the output of which is connected to the first input of the second comparison unit, the second input of which is connected to the third output of the first threshold comparison unit, and the output to the second input of the first operational amplifier, the second input of the second threshold comparison unit is connected to the third output the set task, and its output is with the first input of the third adder, the second input of which is connected to the output of the third threshold comparison unit, and the output — with the input of the switching regulator — of the threshold comparator unit is connected to the voltage levels, the second input of the third stroke of the fourth task block.