SU1422351A1 - Reversible d.c. electric drive - Google Patents

Abstract

The invention relates to electrical engineering and can be used to control electric motors. operating in the mode of frequent starts and braking. The aim of the invention is to increase the reliability of the drive. The drive contains a block 30 of logic control; 7, the first six inputs of which are connected to the outputs of block 15 of the definition of characters. The seventh input of block 30 is connected to the first output of the relay element 23, the second output 32 of which is connected to the eighth input of block 30. The ninth input of block 30 is connected to the output of delay block 25, and the output to the second 26 and third 27 controlled keys. This device provides prevention of emergency situations caused by (faults in the control system or reversing the air driver. 1 s, n, / L f-ly, 4 Il.

Description

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The invention relates to electrical engineering, in particular, to thyristor Drives of direct current operating in the mode of frequent starting and braking, and can be used in electric drives of drilling winches of modern drilling rigs of various capacities.

The purpose of the invention is to increase the reliability of the drive.

FIG. 1 shows a functional diagram of the drive; in fig. 2 - the same, block of definition of signs and pervb: Go block of logic control; in fig. 3 - the same, the second logical control unit; in fig. 4 then the current zero indicator of the current.

The reversible electric drive contains a DC motor,; root winding 1. of which iK is connected to an irreversible thyristor converter; head 2, the intensity control 3 is sequentially connected to the iPoro control circuit, the speed regulator A with the limiting unit, the first control key 5, the link 6 with a tunable structure, the unit 7 the module is inserted and the current control box 8 is turned on, and the motor excitation winding 9 is connected to a reversible thyristor converter 10, in the control circuit of which the EMF control unit 11 and the drive current regulator 12 are connected in series speed sensors 13 and excitation current 14 connected to the inputs of the respective regulators, character detecting unit 15, whose inputs are connected to the outputs of speed regulator 4, excitation current sensor 14 and speed sensor 13, and six codes 16–21 are connected to six inputs of the first unit, 22 logic control, while the first output of logic control unit 22 is connected with the control input of the control key 5, its second output with the control input of the link 6 with a tunable structure, and the third output with the rate control input The output signal of the intensity setting device 3 and the control input of the limiting unit of the speed controller 4. The electric drive also contains a sign-sensitive relay element 23, an excitation current indicator 24, a delay unit 25, control switches 26 and 27, resistors 28 and 29

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and the second logical control unit 30 with nine inputs, the first six inputs of which are connected respectively to six codes 16-21 of the character definition block 15, the seventh input is connected to the first output 31 of the sensitive relay element 23, the second output 32 of which is connected to the eighth input of the block 30 logic control, the ninth input of which is connected to the output 33 of the delay block 25, and the output of the logic control block 30 is connected to the control inputs of the second 26 and third 27 control keys. The logical control unit 30 (Fig. 3) consists of four AND 34-37 logic elements, three IL-38 logic elements 40-40 and a delay 41 block for the appearance of a signal. The outputs of the logic elements 34 and 35 are connected respectively to the first and second inputs of the logical element OR 38, the outputs of the logic elements 36 and 37 are connected respectively to the first and second inputs of the logical element OR 39, the output of the logical element OR 38 through the block 41 delays and the output of the logical element OR 39 is directly connected to the first and second inputs

logical element OR 40, the output of which is the output of the block 30 of logical control.

The first 16 and second 17 outputs of the character detection unit 15 are connected respectively to the first input of the second 35 and the first input of the first 34 logic elements AND logic control unit 30, the third input 18 of the character determination unit 15 is connected to the first input of the indicator 24 zero excitation current and the second logical input element 3 of the logic control unit 30, a quarter output 19 of the character determination unit 15 is connected to a second input of the indicator 24 zero of the excitation current and a second input of the logic element 35 of the logic control unit 30, n fifth 20 and sixth 21 outputs the block determining marks 15 are respectively connected to the second input of the AND gate 36 and the second input of the AND gate 37 logical control unit 30. Vkod link 6 with a tunable structure connected to the input of the signal-sensitive relay314

element 23, the outputs 31 and 32 of which are connected respectively with the third input of the logic element 35 and the third input of the logic element 34 of the logic control unit 30, the output of the indicator 24 of the excitation current zero is connected to the input of the delay unit 25, the output of which is connected to the third the inputs of logic elements AND 36 and 37 of the block 30 of the logical control. The control key 26 is connected between the output of the module allocation unit 7 and one output of the resistor 28, and the control key 27 is connected between the output of the EMF control unit 11 and one output of the resistor 29, the second output of which is combined with the second output of the resistor 28. and with a common point.

The zero current indicator 24 (Fig. 4) contains two logical elements HE 42 and 43 and logical element AND 44, whose inputs are connected to the outputs of logical elements HE 4 and 43, and the output is the output of indicator 24,

The reversible DC motor works as follows.

If the drive operates in the first quadrant of the mechanical characteristics in the motor mode in the lifting direction, then the outputs of the speed controller 4, sensor 14 of the excitation current and speed sensor 13 contain signals of positive polarity. With such a combination of signal symbols, the signals of the logical unit are present at the inputs of the character determination unit 15 and its outputs 16, 18, and 20, and the logic zero signals at outputs 17, 19, and 21. At the same time, at the first output of logic control unit 22 (Fig. 2) there is a signal of a logical unit and the control key 5 is closed. On the second and third outputs of the logical control unit 22 (Fig. 2) there are signals of logical zero. Due to the fact that the first controlled key 5 is closed, a positive polarity signal is also present at the output of the link 6 with a tunable structure, which results in the appearance of a logical unit signal at the first output 3t of the sensitive signal relay element 23 and the signal of the logical zero at its second output 32 ,

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Since the excitation current is different from zero and positive, the output of the indicator 24 is the zero of the excitation current (Fig. 4), and consequently, at the output 33 of the delay unit 25 there are logical zero signals. With such a combination of logical signals at the inputs of the logic control unit 30 (Fig. 3) associated with the outputs 16-21 of the character detection unit 15, the outputs 31 and 32 of the sensitive sensing relay element 23 and the output 33 of the delay unit 25, at the outputs of all logic elements I 34 - 37 signals of logical zero are present. Such a logical signal is also present at the output of the logical element OR 40. Due to this, the controllable keys 26 and 27 are open.

During braking, in the process of decreasing the excitation current to zero, the output of the speed controller 4 contains a negative polarity signal, and the outputs of the sensors of the excitation current 14 and speed 13 contain signals of a positive polarity. With such a combination of signal symbols, the signals of the logical unit are present at the inputs of the block 15 for determining signs at its outputs 17, 18, and 20, and the signals of logical zero at the outputs 16, 19, and 21. In this case, during normal operation of the elements of the logical control unit 22, a logical zero signal is present at its first output, and during normal operation of the control key 5, the latter is open. At the output of the link 6 with a tunable structure, which, due to the presence of a single logical signal at the second output of the logical control unit 22, is transferred from proportional to aperiodic, the signal is zero. Due to this, both on the first 31 and on the second 32 outputs of the signal-sensitive relay element 23 there are signals of logical zero. Since the excitation current is not equal to zero, the output of the indicator 24 is the zero of the excitation current and the output 33 of the delay unit 25 contains the signals of logical zero. With such a combination of logical signals at the inputs 16-21, 31-33 of the logic control unit 30 (FIG. 3), the outputs of all the logical elements AND 34-37 contain the signals of the logical zero. Such a logical signal is also present at the output of the logical element OR 40. Due to this, the controlled keys 26 and 27 are open. If, due to a malfunction of the elements of the logic control unit 22 or the control key 5, the latter, when braking, is closed, a situation arises when, with a negative signal at the output of the regulator, 4 speeds, positive signals at the outputs of the excitation current sensors 14 and speed 13, at the output of the link 6 with a tunable structure there is a signal of negative polarity. At the same time, at the first output 31 of the sign-sensitive relay element 23 there is a logical zero signal, and at the second 32 output - a signal of a logical 20 unit. With such a combination of logic signals at inputs 16-21, 31-33 of logic control unit 30, the signal of the unit appears at the output of the AND 34, 25 logic element and the outputs of the remaining logical elements 35-37 are logic zero signals. The signal of the logical unit appears at the output 38 of the logic element OR 38 and with a time delay defined by the delay unit 41, the signal of the logical unit appears at the output of the logical element OR 40. This leads to the closure of the controlled switches 26 and 27 , locking the non-inverter converter 2 and reducing the excitation current to zero. Due to this, the drive stops quickly.

In the event of a similar situation when a drive operating in the third quadrant is braked, all processes proceed in a similar way, with the only difference that the appearance of the logical unit signal at the output of the logical element OR 40 is determined by the presence of the signal of the logical unit at the output of the logical element And 35, since only at the inputs 16, 19 and 31 of this logical element: (fig, 3) there are signals of logical unity (T).

If the electric drive operates in the third quadrant of the mechanical characteristic in the power-speed mode, the outputs of the controller 4 are speedy 55 and, the excitation current sensors 14 and 13 and the speed signal are flashing polarity. With such

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Signal combinations of signals at the inputs of the block 15 for determining signs at its outputs 16, 18, and 20 contain signals of logical zero, and at outputs 17, 19, and 21, signals of a logical unit. At the same time, at the first output of logic control unit 22 (Fig. 2) there is a signal of a logical unit and the control key 5 is closed. On the second and third outputs of the logical control unit 22 (Fig. 2) there are signals of logical zero. Due to the fact that the controlled key 5 is closed, a negative polarity signal is also present at the output of the Avene 6 with a tunable structure, which results in the appearance of a logical zero signal at the first output 31 of the signal-sensitive relay element 23 and the signal-. the logical unit at its second output 32. Since the excitation current is different from zero and negative, the output of the indicator 24 is the zero of the excitation current (Fig. 4), and consequently, the output 33 of the delay unit 25 contains the signals of the logical zero. At. Such a combination of logical signals at the inputs of the logic control unit 30 (FIG. 3) associated with the outputs 16-21 of the character detection unit 15, with the outputs 31 and 32 of the sensitive sensing relay element 23 and with the output 33 of the delay unit 25, at the outputs of all logic elements And 34 - 37 signals of logical zero are present. Such a logical signal is also present at the output of the logical element OR 40. Due to this, the controlled keys 26 and 27 are open. Due to the weight of the load, the actual speed of the electric motor exceeds the set speed, and a positive polarity signal appears at the output of the speed controller 4. In this case, the control key 5 is opened, and at the output of the link 6 with a tunable structure, the signal is zero. The field current decreases to zero. When the excitation current reaches zero, the logic zero signals appear at the outputs 18 and 19 of the character detection unit 15 (FIG. 2). At the same time, at the outputs of the logical elements HE 42, 43 and the logical element AND 44, a signal of the logical unit appears. If due to a malfunctioning reverse thyristor71

In the case of a converter 10, the excitation current of a given positive polarity does not appear, then with a time delay determined by the delay unit 25, a signal of a logical unit appears at its output 33. Thus, the following logic signals are present at the inputs of the logical control unit 30 (FIG. 3): at BXO

dakh 16, 21 and 33 units, on the remaining inputs 17 - 20, 31. and 32 zeros. In this case, the signal of the logical unit appears only at the output of the logical element I 37, and consequently, at the outputs of the logic elements .. OR 39 and 40. This leads to the closure of the controlled keys 26 and 27, the locking of the thyristor converter 2 and stop the drive. In the event of a similar situation arising when the electric drive operating in the lifting direction is braked, all processes proceed in a similar way, with the only difference that the appearance of a logical unit signal at the output of the logical element OR 40 is determined by the presence of a logical unit at the output of the logical element And 36, since On all inputs of this logical element only, signals of a logical unit are present. Thus, in the proposed device for controlling the reversible electric drive, reliability is increased by preventing emergencies caused by faults in the control system or reversing agent.

Formula of invention

Claims (2)

1. A reversed DC electric drive containing an electric motor whose root winding is connected to an irreversible thyristor converter, the control circuit of which includes serially connected intensity adjuster, speed controller, control key, link with a tunable structure, a module and a module the current control unit is a core, and the motor excitation winding is connected to a reverse thyristor converter, in the control circuit of which the unit regulating the emf whose input is connected to the control voltage speed controller and field current controller connected to the inputs of the respective controller speed sensor and field current sensor, a character detection unit, the inputs of which are connected to the outputs of the speed controller, field current sensor and Q sensor 15 20 25 thirty 35 40 45 50 55 speeds, and six outputs — with six inputs of the first logical control unit; the first output of the first logical control unit is associated with the control of the control key input, its second output with the control input of the link with a tunable structure, and the third output with the control input of the rate of change of the output signal of the intensity setter and with the control input of the organization unit in the feedback loop of the speed regulator, characterized in that, in order to increase the reliability of the drive, Briefly, a sign-sensitive relay element, a zero indicator of the excitation current, a delay unit, a second and third controlled keys, two resistors, and a second logic control unit with nine inputs, consisting of four AND gates, three OR gates, and a delay block, are entered this outputs of the first and second logical elements And are connected respectively to the first and second inputs of the first logical element OR, the outputs of the third and fourth logical elements And are connected respectively to the first and second input -; The second logic element HJffl, the output of the first logic element OR through the delay unit and the input of the second logic element OR are directly connected to the nepBoi iy and the second inputs of the third logical element OR, the output of which is the output of the second logic control unit, the first and second codes of the character determining unit connected, respectively, to the first input of the second and first input of the first logic elements AND the second logical control unit; the third input of the character determining unit is connected to the first input the house of the zero indicator of the excitation current and the second input of the first logic element AND the second logic control unit, the fourth output. block definition signs connected to 9142 the second input of the zero indicator of the excitation current and the second input of the second logic element AND the second logical control unit, the fifth and the second outputs of the character detection unit i are connected respectively with the second : the input of the third and the second input of the fourth logic element AND the second logic control unit, the output of the tunable structure connected to the input of the sensing relay element, the first ; and the second outputs of which are connected respectively to the Third input of the second and third input of the first logic elements AND the second logic control unit, the output indicator of the excitation current is connected to the input of the delay unit, the output of which is connected to the third inputs of the third and fourth logic elements AND  / 3 Y6 Q about five ten the second logical control unit, the output of which is connected to the control inputs of the second and third controlled keys, with the control inputs of the second and third controlled keys, the first of which is connected between the output; the selection module and one output of the first resistor, and the second between the code of the EMF control unit and one output of the second resistor, the second output of which is combined with the second output of the first resistor and the common point. 2. The actuator according to claim 1, characterized in that the zero indicator of the excitation current contains two logical elements NOT and the logical element I, whose inputs are connected to the outputs of the logical elements NOT, and the output is the output of the indicator zero of the excitation current. 2Z (time 2  ; I DaS 3 j