SU1005256A1 - Dc drive - Google Patents

Description

An electric motor and speed sensor connected to the speed controller inputs and a speed sensor and a current sensor connected to the input of the first current controller have a starting current controller with a limiting node and two opposite-parallel diodes, while the starting current controller inputs are connected to the setpoint device and a speed sensor, and its output through the aforementioned diodes is connected to the input of the first current controller, and the output of the speed sensor is additionally connected to the input of a thyristor converter.

In the drawing, an electric drive circuit is functional.

The electric drive contains serially connected speed controller 1 with limiting node 2, first current regulator 3 with limiting node 4, second proportional-integral current regulator 5 and thyristor converter b, supplying the rotor circuit of the electric motor 7, as well as connected to the controller inputs 1 speed setting device 8 and speed sensor 9 and current sensor 10 connected to the input of the first current regulator 3.

A start-up current regulator 11 with a limitation node 12 and two anti-parallel-connected diodes 13 are also introduced into the drive, while the inputs of the starting current regulator are connected to the setpoint 8 and the speed sensor 9, and its output is connected to the first diodes 13 regulator 3 current. The output of the speed sensor 9 is additionally connected to the input of the thyristor converter 6. Nodes 2.4 and 12 of the limits of the regulators 1.3 and 11 have a relay characteristic.

The drive operates in the following manner.

In the input circuits of the speed controller 1, the target and measured speeds of the electric motor are compared. because of the characteristics of the speed controller 1, it is possible to obtain the following output signals: zero: if the compared signals are the same, and stable, the polarity of which is determined by the matching sign between the compared signals, and the value does not depend on the magnitude of the error. at the input of the starting current controller 11, amplified, inverted, limited and supplied to the diodes 13. If the output signal of the controller 11 exceeds the direct voltage drop and diodes 13, it is fed to the input of the first current regulator 3, wherein q is summed output signal of the current sensor 10 and is subtracted from the output signal of the controller 1 skoroeti. The output of current regulator 3 is simultaneously scaled and integrated by the second current regulator 5 and summed at the input of the thyristor converter 6 with the output of speed sensor 9.

Processes in the core circuit of a dc motor with a constant excitation flow are described by the equation

dl

and

E -

idt

where and

- output voltage

converter g E - motor EMF; 1 - current of the root circuit; R, L is the resistance and inductance of the engine's main circuit. Not allowing a significant error, it is possible to consider the thyristor converter as a speedless link with the transmission coefficient K „

n therefore

 .. |, R, .L, - (;

for the case of a linear change in the current of the motor with a given, permissible according to the switching conditions on the collector,

V .-- cow.

+

corresponds to the acceleration of the engine.

 + C (0), (g)

where 1 (o) is the initial value

cor.

Dividing (1) by K, we get

2:

U. p h

 1: 1.

where 1 „I R ,,

Equation (3) can be in the form

and

and. z +

where and

 Kp 9 P

Claims (2)

Consequently, in order to form a given, (linear) law of change of the motor's crust current, it is necessary to apply the sum of the voltages U. and and to the converter input. The voltage U is proportional to the measured value of the EMF of the motor and is the output voltage of the corresponding sensor in a certain scale. The voltage U can be formed by an integral-proportional current regulator 5 at a jump input action provided by the current and speed regulators 3 and 1. A change in the feedback level of the regulator 3 or the limiting level of the output voltage of the regulator 1 causes a change in the maximum magnitude of the current cor. By varying the level of limiting the output voltage of the regulator 3, it is possible to control the rate of change of the current cor. The engine is started in the system by inputting a stepped driver signal at the maximum allowable current level (limiter I) with a given rate of its rise. To enable the engine to start at a given rate of change of speed less than the maximum allowable, and regulator 11 and diodes 13 are introduced into the system to form the current diagram corresponding to this rate. Regulator 11 of starting current, as can be seen from the diagram, is proportional and with controller 1 has a lower coefficient and a lower level of limiting the output signal. When the engine is started, in this case, the input of the regulator 3 is affected by the signal difference from the outputs of the regulators 1 and 11, which corresponds to a lower level of current setting, a lower current and a lower rate of its increase. The purpose of the diodes 13 is to exclude the effect of the inrush current regulator in the disturbance testing mode for the load. The high speed of the system provides a small change in the speed (EMF) of the engine when a load is applied, which causes a slight change in the output voltage of the starting current regulator 11, which is completely damped by the direct resistance of the diodes 13. The implementation of the proposed device allows improving the performance of equipped with a similar drive, due to a more complete use of engine overall power. By choosing the settings of the regulators, the operation mode of the electric machine can be brought closer to the limiting one, without fear of possible overloads and a premature collector from the nose. DETAILED DESCRIPTION OF THE INVENTION An electric current drive comprising an electric motor and a speed controller connected in series with a limiting unit, a first current regulator with a limiting unit, a second proportional-integral current regulator and a thyristor converter, a power supply for the electric motor speed sensor, a speed sensor and a speed sensor and a current sensor connected to the input of the first current controller, characterized in that, in order to improve the quality of regulation and more complete Using an electric motor, a starting current regulator with a limiting node and two oppositely connected diodes are entered into it, while the inputs of the starting-current regulator are connected to the presetter and the speed sensor, and its output through the mentioned diodes is connected to the input first regulator.current, and the output of the speed sensor is additionally connected to the input of the thyristor converter. Sources of information taken into account in the examination 1. M. Chilikin, V. Klyuchev, A. Sandler. Theory of automated electric drive. M., Energie, 1979, p. 516-517: 2.Garnov V.K., Rabinovich V.B., Vishnevetsky L.M. Unified system of electric motor autosteering in metallurgy. M., Metgshlurgi, 1977, pp.127-128.