SU1461839A1 - Apparatus for controlling the electric motor of slewing gear of quarry excavator - Google Patents

Abstract

The invention relates to mining machinery and allows to increase the productivity of a mining excavator. For this, the device is equipped with an optoelectronic converter (OED) 11, the output circuit of which is connected to the first and second inputs of the first current limiter (OT) 4. The first input circuit of the OEP 11 is connected to the positive input of the direct current source 14 and the first input of the com- mand controller (CC ) 6. To the second QC input, the negative output of source 14 is connected via the second OT 13. The output of QC 6 is connected to the first input of a voltage limiter, the output of which is connected to the input of a rectifying bridge 9. To the second input circuit with {C

Description

one

The invention relates to mining machinery and can be applied in electric drives of excavator turning mechanisms.

The aim of the invention is to improve the performance of a career excavator.

FIG. 1 is a block diagram of the control device; in fig. 2 - static characteristics of the electric motor; in fig. 3 - characteristic of the voltage limiter; in fig. 4 is a functional circuit of the optoelectronic converter.

The device contains a drive motor 1, a power converter 2, a current regulator 3, a current limiter 4, a voltage regulator 5, a controller 6, a voltage limiter 7, a voltage sensor 8, an overvoltage bridge 9, a voltage stabilizer 10, opto-electronics converter 11, current limiters 12, 13, DC source 14. .

Optoelectronic converter in one of the possible implementation options contains optocouplers 15 and 16, the transistor 17 and the diodes 18-21.

The device works as follows.

The supply of the driving voltage to the driving input of the current regulator 3 is carried out as follows. In the case of a positive voltage at the output of the voltage regulator 5, this voltage is supplied through the diode 18, the current limiter 4 and the diode 21 to the driver input of the current regulator 3. In case of a negative voltage

The output of the regulator 5 is the voltage through the diode 19, the current limiter 4 and the diode 20 also enter the driver input of the current regulator 3. Thus, the use of a rectifying bridge formed by diodes 18–21 ensures that current passes through current limiter 4 and the OP collector emitter circuit of transistor 17 in one direction only, regardless of the polarity of the voltage at the output of voltage regulator 5.

The operation of the optoelectronic converter 11 consists in changing the resistance of the collector-emitter circuit of transistor 17, which shunts part of current limiter 4, depending on the base-emitter circuit current value

0 of the transistor 17, and the change of this current is carried out as a function of the input signals of the optoelectronic converter — the currents through the emitters of the diode optocouplers 15 and 16. As a result, the equivalent resistance of the section of the output of the voltage regulator 5 — the driving input of the current regulator 3 changes Yiwu thus, the voltage at the driver input of the current regulator 3 is regulated as a function of the input signals of the optoelectronic converter 11 - currents through the emitters of the optocouplers 15 and 16.

Thus, for example, at a small amount of current flowing through the emitter of the optocoupler 15, the value of the reverse photocurrent flowing through the photodiode of the optocoupler 15 is negligible and the transistor 17 operates in a cut-off mode. With this resistance

The collector-emitter circuit of transistor 17 is the maximum.

When the current flowing through the optocoupler 15 emitters increases, the light power of the emitting diode increases, the value of the reverse photocurrent flowing through the photodiode of the optocoupler 15 increases, as a result of which the current in the base-emitte circuit of transistor 17 increases, it goes into active mode and the collector-emitter circuit resistance transistor 17 will decrease.

When a certain value of the reverse photocurrent flowing through the photodiode of the optocoupler 15 is reached, the transistor 17 switches to a full mode and the collector-emitter junction resistance of the transistor 17 will be minimal.

The operation in control with optocoupler 16 is similar. When controlling the acceleration process of the electric drive, the control unit of the controller 6 moves from the zero position to the extreme one that is required to the right. the movement of motion. At the same time, the speed reference signal arriving at the first input of voltage regulator 5 and to the first input of voltage suppressor 7 gradually rises from zero to maximum value.

The output of the supply converter 2 is voltage and the motor 1 begins to accelerate. The voltage applied to the core of the electric motor 1 increases, the negative feedback signal of the electric motor voltage applied to the inputs of the voltage regulator 5 and the voltage limiter 7 increases. The voltage at the output of the limiter 7 is proportional to the difference in the signals of the speed reference and the negative feedback on the voltage of the electric motor.

At small values of the speed reference signal, the voltage regulator 10 does not break through and the current in the input circuit of the optoelectric converter 11 does not flow. In this case, due to the presence in the circuit of the setting of the regulator 3 current of the current limiter 4 with high resistance, the setting of the current controller is small and the current of the core, and consequently, the torque of the electric motor will be small. Value of

39t

The current limiter resistance is chosen such that the time developed by the electric motor at the same time ensures a smooth selection of gaps in the transmission. This value of the speed reference signal corresponds to the characteristic XI of the electric motor with a stopping current 1, shown in FIG. 2. 10 Upon further movement of the control unit of the controller, the speed reference signal increases, the voltage applied to the voltage stabilizer 10 reaches the breakdown voltage, and a current appears in the input circuit of the optoelectronic converter 11. However, at small values of this current, there is no change in the resistance of the output circuit of the epto-20 electronic converter 11 and ve. The setting of the current controller does not change. This value of the speed reference signal c: corresponds to the mechanical characteristic of the X2 electric engine 25, shown in FIG. 2. The voltage value of the voltage regulator 10 is chosen such that when the speed of movement of the control body of the controller is natural, without tension from the driver, they have time to select the gaps in the gear.

With further growth of the speed reference signal, the current in the input circuit of the optoelectronic converter 11 reaches a value at which the resistance of the output circuit of the optoelectronic converter 11 begins to decrease, which leads to an increase in Dani's 4Q current regulator and a gradual increase in motor torque. The intermediate characteristics of an X3, X4 and X5 electric motor 35 correspond to this value of the speed reference signal.

4g l with stop currents I

CT, i

-st.z

Art. four

shown in FIG. 2. On 50

five

and I

The presence of intermediate mechanical characteristics such as the characteristics of X3, X4 and X3 contributes to increasing the smoothness of the core current increase from the minimum to the maximum allowable value of 1CT. 4 When the current in the optog electronic circuit of the electronic converter 11 reaches its maximum value, the resistance of the output element of the optoelectronic converter 11 occurs the output circuit becomes minimal, and the reference signal

the current controller is the maximum, which provides for the acceleration of the electric motor with the maximum permissible acceleration at the selected gaps. This value of the speed reference corresponds to the characteristic X6.

A further increase in the speed reference signal does not cause a change in the resistance of the output circuit of the optoelectronic converter 11. Therefore, until the maximum speed is reached, the torque of the electric motor will be maintained at the maximum permissible level. Characteristic X7 corresponds to the maximum value of the motor speed.

The formation of sections of characteristics XI, X2, Kb and X7, which are in the first quadrant (Fig. 2), corresponds to the known system of subordinate regulation. It should be noted that these characteristics are given as: to the integral law of current control with parameters that provide zero rigidity of the current limiting section, since the characteristics XI and X2 correspond to a higher value of the current limiter A, which reduces the drive the transfer coefficient of the current regulator 3, and hence the gain of the entire system, the working areas of these characteristics are slightly softer than those in the characteristics X6 and X7.

Let us consider in more detail the formation of the characteristics of HZ. To do this, we use the one shown in FIG. 3 by the characteristic of the limiter 7 voltage - the dependence of the voltage at the output of the limiter on the magnitude of the control voltage Ui at its input. FIG. 3 The following basic notation is accepted:

and

values accordingly

etc-

  % but control voltage and voltage

at the output of the voltage limiter at which the voltage stabilizer 10 starts to punch;

U |., Up - values of the same voltage, at which the resistance of the output circuit of the optoelectronic converter begins to decrease.

and Uro are the values of the same voltage at which the resistance of the output circuit of the optoelectronic converter 11 becomes W1 minimum

, - values of the same napr 61839

and,

zheniye, corresponding to the established mode of operation on the main work

whose characteristic X7 of FIG. 2;

and

us

- the value of the saturation voltage of the voltage limiter.

Point and characteristics of HZ soot10

etc

15

20

The value and, at which the resistance value of the current limiter 4 has the maximum value. Plot AB is formed by an automatic voltage control circuit at the output of the supply converter 2 with the help of voltage regulator 5. When the load is increased, the voltage of the electric motor 1 decreases so much that the voltage regulator switches to the nascent mode, and the current regulator 3 forms the area b-in the characteristics of X. At point B, due to a significant decrease in the voltage of the electric motor 1, the voltage 25 of the control of the voltage limiter 7 reaches the value Uu, at which the resistance of the output circuit of the optoelectronic converter 11 begins to decrease. As 30 further decreases the voltage. motor 1, the magnitude of the reference for setting current regulator 3 increases and the current of the motor core increases. Thus, it forms with the section c-d characteristics of the chorus. Similarly, the formation of the characteristics of XA and X5. However, due to the fact that the characteristics of X4 and X5 in steady state operation

40

correspond to large values

ui Uu and uf Ui, for example, p

45

-

g;

the length and duration of these characteristics will be achieved with a smaller change in the voltage of the electric motor. Therefore, the length of the sections of b '-v and b-c of these characteristics is less than that of the segment of b-in. At point g of characteristic X5, the value U is reached at which the value of the setting of current regulator 3 reaches the maximum value. A further decrease in the voltage of the motor with increasing load does not change the setting of the surge current regulator 3. . This causes the formation of the vertical section of the current limiting with the maximum value of the current amounting to 1-4. For the characteristics of X3 and X4, this value

50

current is achieved when operating in the IVth quadrant.

When the EMF of the electric motor 1 becomes greater than the emf of the supply converter 2, the characteristic of the HZ goes into the 11th quadrant. Accordingly, the voltage on the electric motor also increases, and at some of its value, the voltage regulator 5 goes into saturation mode, at which the formation of the vertical section of the e characteristic of the XZ occurs. Due to the supply to the input of the voltage suppressor of a negative feedback signal on voltage with a constant reference signal and an increase in voltage on the motor, the value of U decreases Ib

and when the voltage of an electric motor

corresponding to point d of the characteristics of the chorus, we have U. Uu. Further increase of the voltage on the electric motor leads to a decrease in Uu to zero and then to a change in its polarity, and consequently, the polarity of the voltage of the voltage limiter 7. Due to the fact that a rectifying bridge 9 is connected to the output of the orj- voltage delimiter 7, the polarity of the signal applied to the input of the optoelectronic converter 11 will not change even when the control voltage reaches the value Uu -Uu the output resistance the opto-electronic converter circuit 11 again begins to decrease. This value of the motor voltage corresponds to the point with the characteristics of the XZ. . Thus, in the area df, the resistance value of the current limiting resistor 4 is maximum and the core current is kept at a minimum current limit of 1..

As seen in FIG. 2, the length of the section of the d e characteristics of the XS is greater than the length of the section of the same characteristic, since during the transition from idle mode to achieve the value of Uu, -Uu. a change in motor voltage is required by a greater amount than to achieve a value and ,. Uu, which is clearly seen in FIG. 3. This factor ensures the limiting of the current in the initial stage of braking to 1, 1, even when the control unit of the commander controller is quickly shifted towards zero 618393.

position, which guarantees a smooth selection of gaps during braking.

With further increase in motor voltage, we have tlknl U .. and

  JO

In the input circuit of the optoelectronic converter 11, a current appears at which the resistance of its output circuit begins to decrease. There is an increase in the setting of the current regulator 3 and an increase in the current of the electric motor core. A plot of e-zhz characteristics is formed. At point g, the value of% -Uu, at which the resistance

15 of the output circuit of the optoelectric converter 11 becomes minimal. Further increasing the voltage of the motor does not change the setting of the controller 3 current. Wherein

20, a vertical portion of the current limiting characteristic of the HZ is formed with a current value of -I.

Similarly, they are continued in the 11th quadrant of characteristics.

25 XI, X2, X4, X5, X6 and X7. Their full continuation in the 11th quadrant is not shown. Only the main part of these characteristics is given before the value-I

stm

executed y0

five

0

five

0

five

nor current core 1

conductive role in limiting

current in the initial stage of braking.

The parameters of the input circuits of the limiting voltage bodies 7 are chosen such that at the maximum speed of the electric motor in the steady state mode of operation, the voltage at the output of the limiter 7 in accordance with FIG. 3 was about iG, i.e.

was a little lower than his hdc voltage

syscheni and. To provide braking and reversal of the electric motor, the control unit of the controller 6 moves in the direction of its zero position, reducing the speed reference signal. Due to the inertia of the drive, the negative feedback signal from the motor voltage decreases more slowly than the backward speed signal, as a result of which the voltage decreases and even changes at the input of the voltage suppressor 7, which leads to a decrease and even disappearance of current in the input optoelectronic circuit converter 11. At the same time, the resistance of the output circuit of converter 11 increases and the setting of the current regulator decreases, thus limiting the brake to the current in the initial stage of braking rotor motor value et. smooth selection of gaps in the transmission.

Similarly, the process of braking proceeds not only from the maximum speed, but also from any intermediate speed.

The shape of the drive characteristic in the zero position of the roller driver command depends on the parameters of the control circuits of the limiter 7. The negative feedback signal voltage applied to limiter 7 can be selected such that when there is no reference signal and the nominal voltage of the motor Uu. uJ .. In this case, when braking by setting the control unit of the commander of controller 6 from the working to zero position, the resistance of the output circuit of the opto-electronic converter 11 will have a maximum value and braking power unit will be maintained at the level of 1 ". Inhibition will be ineffective.

If, however, we choose the magnitude of the signal for negative feedback on

in the said circuit of the optoelectronic converter 11, a current is reached at which the resistance of the output circuit of the optoelectronic converter 11 becomes minimal. In this case, the motor will have a characteristic X9, which provides very effective braking.

FIG. 2 also shows the characteristics X10 ... X16, corresponding to the opposite direction of rotation of the electric motor. Their formation occurs as described.

The magnitude of the current in the input circuit of the optoelectric converter 11 is limited by the appropriate choice of current limiter 12 and the voltage of the voltage limiter 7.

Claims (1)

Invention Formula 25 A device for controlling an electric motor of the mechanism for turning a mining excavator containing a commander controller, the output of which is connected to the first input of the regulator to the injection given to the input of the constraint ZOi, the output of which is connected to the first body 7, such that in the absence of the input of the first current limiter, the output of which through the current regulator is connected to the input of the power supply converter, the outputs of which are connected to the power supply circuits of the electric motor and the voltage sensor inputs, the output of which is connected to the second input of the voltage regulator, voltage limiter, second and third limits - current bridge, quick bridge, voltage stabilizer, direct current source, characterized in that, in order to improve the performance of the mine excavator-45 R device, an optoelectronic transducer is introduced The output circuit of which is connected to the first and second inputs of the first current limiter, the first input circuit of the optoelectronic converter is connected to the positive terminal of the DC source and the first input of the controller, the second input of which is connected to the negative terminal of the DC source, output the controller is connected to the first input of the voltage limiter, the output of which is connected to the input of the reference of the reference signal and the nominal voltage of the electric motor l Uu, Uy, when the motor zero position Komandokontroller 6 will possess characteristic X8. With this form of performance and deceleration from the nominal speed, the initial stage of the deceleration process proceeds very effectively, since the magnitude of the braking current is determined by the value -1. As the speed drops to the value determined by point z of the X8 characteristic, the braking current gradually decreases to –I ff t (plot and-to characteristics X8), and then to zero. However, even with this characteristic, the braking time is too long, and in order to reduce it, it is necessary to eliminate the braking by reverse. Due to the inclusion of a current limiter 13 in series with another input circuit of the optoelectronic converter 11 and spreading the zero block contact of the controller 6 when the control body of the controller 6 is set to the zero position -. ZO a, whose output is connected to the first 35 40 the input of the first current limiter, the output of which through the current regulator is connected to the input of the power supply converter, the outputs of which are connected to the power supply circuits of the electric motor and the voltage sensor inputs, the output of which is connected to the second input of the voltage regulator, voltage limiter, second and third limits - current bridge, quick bridge, voltage stabilizer, direct current source, characterized in that, in order to improve the performance of the mine excavator-45 R device, an optoelectronic transducer is introduced The output circuit of which is connected to the first and second inputs of the first current limiter, the first input circuit of the optoelectronic converter is connected to the positive terminal of the DC source and the first input of the controller, the second input of which is connected to the negative terminal of the DC source, output the controller is connected to the first input of the voltage limiter, the output of which is connected to the input of the rectifier50 55 A tel bridge, the output of which is connected in series to the voltage regulator and the third current limiter is connected to the second input circuit of the electronic npeoOp; i- subscriber, the output of the voltage sensor is connected to the second input of the voltage limiter. FIG. Thebes. Oh