SU1552324A1 - Dc electric drive with flexible coupling between electric motor and mechanism - Google Patents

Abstract

The invention relates to electrical engineering and can be applied to control the thyristor electric drive of direct current of industrial mechanisms, the load of which varies over a wide range, for example, lifting winches of oil-drilling installations. The purpose of the invention is to increase the reliability of the electric drive with automatic power limitation. An indicator 20 is additionally introduced into the device, relay elements 21 and 22, an OR-NOT 23 logic element, a control key 24, a sampling-storage device 25, low-pass filters 26 and 27, and a module allocation module 28. Achieving a positive effect is determined by the fact that the limitation of the maximum motor speed at a given value of the load torque occurs as a function of the calculated value of the static load current. 2 Il.

Description

all acceleration in the first zone of adjusting the mask of the signal at the output of the device

speed, the excitation current is equal to the nominal, at the output of the level indicator 20 there is a logical O signal, and the sample-storage device 25 is switched to the Sampling mode.

The signal at the output of the proportional link 32 is proportional to the current static load I

-St

U, 2 (p) KTflICT (p)

one

Where

Km "rcc current feedback coefficient of the core; the integrator time constant is 30;

amplification factor of proportional link 32. By appropriate selection of T and K values, the dynamic error of determining the static load current can be made quite small, since sampling and storage device 25 operates in Sampling mode, the signal from the output of proportional link 32 is fed to the input of power control unit 19. Despite this, even at the maximum output signal of the sampling-storage device 25, while the drive accelerates in the first speed control zone, the output signal of the power control unit 19 cannot become less than the output signal of the second proportional amplifier 37, which is proportional to the fundamental value the speed of the drive. If the load of the electric drive is such that the signal at the output of the intensity sensor 7 (Fig. 1) exceeds the value corresponding to the base speed, the dependent electric field weakening system of the electric motor takes effect. As soon as current

25 sampling-storage.

Thus, with the load present, the value of the speed reference signal at the output of the intensity setter 7 depends on the static load current. If the load of the electric drive is large enough, the signal at the output of the power control unit 19 corresponds to the main speed,

weakening the floor does not occur, and

sampling-storage device 25 does not go into information storage mode. After stopping the drive signals at the inputs of the first 21 and second

The 22 relay elements become zero. In this case, the output of the logical element OR NOT 23 appears

the signal is logical and the control key 24 is closed, so that

the signal at the output of the sampling-storage device 25 is zeroed and it is being prepared for the next work cycle.

The module allocation unit 28 is inserted into the system to ensure its operability both when moving forward and moving backward, and the first 26 and second 27 low pass filters effectively filter out the high frequency components in the signals of the current sensor 16 of the core and the speed sensor 15.

The work of the proposed system when moving the drive in the backward direction occurs in a similar way.

Achieving a positive effect is determined by the fact that the proposed technical solution limits

The maximum motor speed at a given value of the load torque occurs as a function of the calculated value of the static load current. In this case, the signal calculation is proportional to

excitation of an electric motor becomes less current than a static load less than the nominal one, on tricks, occurs only during operation

level 20 indicator appears constant flow sig drive

Logical 1, and the device 25 excitation. When switching to mode

sample-storage is transferred to the field weakening mode computed value

the current is remembered and determines the maximum speed value.

These differences make it possible to increase the reliability of operation of the electric drive, since it eliminates a special weight sensor mounted on the fixed end of the wire rope.

In addition, the calculation of the static load current from the information about the electric current of the electric motor and its rotational speed makes it possible to increase the accuracy of setting the maximum speed depending on the static torque.

koy load.

Claims (1)

Formula of the invention A DC electric drive with elastic coupling between an electric motor and a mechanism containing a DC electric motor, the root circuit of which is connected to a thyristor converter, the control circuit of which is connected in series by a selsyn controller, a phase-sensitive rectifier, proportional amplifier an adjustable limiting unit in the feedback circuit, an intensity setter, a speed controller and a current controller kor, and a motor winding l is connected to a thyristor exciter, the control circuit of which includes a series-connected task block, an emf regulator and a field current regulator connected to the inputs of the corresponding regulators of the speed sensor, core current, emf and excitation current, as well as a power control unit whose output connected to five 0 five 0 five 0 the control input of the adjustable limiting unit, characterized in that, in order to increase the reliability of the drive during the automatic power limitation, a level indicator, two relay elements, an OR-NOT logical element, a control key, a sampling device, are additionally introduced into it storage, two low-pass filters, a module allocation unit and serially connected first adder, integrator, second adder and proportional link, the output of which is connected to the subtractive input of the first adder and input the sampling-storage unit connected by its output to the input of the power control unit, the output of the current sensor cor through the first low pass filter i is connected to the summing input of the first adder, the output of the speed sensor through the module allocation unit and the second low pass filter connected to the subtracting input of the second adder, the output of the excitation current sensor through the level indicator is connected to the control input of the sampling-storage device, the output of the phase-sensitive rectifier is connected through the first relay element to the first input OR-NOT, the second input of which is connected to the output of the second relay element connected by its input to the output of the second low-pass filter, and the output of the OR-NOT logic element is connected to the control input of the control key connected in parallel with the sample-storage device. fe Memory $ 35 i 6Y / 37 L (5r ..J UCMZ Faye. 2