RU1802393C - Device for control over electric motor - Google Patents

Abstract

Usage: can be used in speed control systems of electric drives of general industrial mechanisms. Essence: in this device in dynamic modes, when the balance of the control system is disturbed, the speed changes, the module of the first derivative of the speed is applied to the second input of the comparator, increasing the reference signal and preventing the comparator from switching. 1 ill.

Description

J The invention relates to electrical engineering and can be used in electric drives of general industrial mechanisms and machine tools.

j The object of the invention is to increase the speed of the device. I The drawing shows a diagram of a device for controlling an electric motor. j The device for controlling the electric motor includes a current setting unit 1 (speed controller), a current sensor 2, a 3-speed controller, a two-channel switch 4, a delay element 5, a comparator 6, the first 7, the second 8 and the retium 9 resistors, a threshold element 10, a speed sensor 11, the controller 3 of the eye having inputs of a predetermined (1) 3d) and a true (Uoc) current value connected to the outputs of the current setting unit 1 and the current sensor 2, respectively. The output of current controller 3 is the output of the device. The control input of the key 4 through the delay element 5 is connected to the output of the comparator 6, the make contact of the key 4 connects the output of the current regulator 3 to the common bus of the device, i the break contact of the key 4 disconnects the power supply of the electric drive control system (SIFU). The first input of the comparator 6 is connected to a common point of the first 7 and second 8 resistors. The second output of the resistor 7 is connected to the output of the current setting unit 1, and the second output of the resistor 8 is connected to the output of the current sensor 2, Serially connected the third resistor 9 and the threshold element 10 are connected by one output to the output of the current sensor 2, and the second output to the first input of the comparator 6.

In addition, a fourth resistor 12, a capacitor 13, and a module isolation device 14 connected in series with one output to the output of the speed sensor 11, and with a second output to the second input of the comparator 6, and a fifth resistor 15. connected to a common the device bus and the second input of the comparator 6.

The device operates as follows.

With the correct functioning of the speed control system of the electric drive and with a load not exceeding the permissible value determined by the threshold of the threshold element 10. the signal

(L

WITH

00

about

Yu

Gj yu

CA)

the first input of the comparator 6 is equal to zero, since the signals Kzd of the set current value and Uoc of the true current value are equal in magnitude and opposite in sign. At the second input of the comparator 6, the reference signal is zero. The comparator b is in the initial state and its output signal corresponds to a logical zero. The signal at the control input of key 4 is equal to zero, the make contact of key 4 is open, and the output signal DBUX of current controller 3 corresponds to the set value of the parameter.

In the event of malfunctions in the drive speed control system, for example, when the sensor, current controller, speed controller, speed and current feedback fail, the controllers become saturated, the equality of signals and zdz and Uoc are violated, the output of the comparator 6 displays a single signal coming through the delay element 5 to the control input of the key 4. The key 4 is activated by connecting the output of the current regulator 3 to the common bus of the device with its make contact. The output signal Out of control of the current controller 3 becomes equal to zero and the motor stops. The NC contact of the key 4 turns off the power of the power key management system, for example, SIFU.

With the correct functioning of the drive speed control system, but with the value of the signal Uoc of the true value of the current exceeding the threshold of the threshold element 10, a signal other than zero arrives at the input of the comparator 1, the comparator 6 switches to the single state, which leads, as in the case of malfunctions to shut off the drive.

In dynamic modes, using the resistor 12, the capacitor 13, and the module extraction device 14, my .dUbc (t) is extracted

dul

dt

first derivative

a speed signal from the speed sensor 11 and is supplied to the second input of the comparator 6, raising the reference signal. An increase in the reference signal prevents the comparator 6 from switching to a single state in dynamic modes (acceleration, braking, reverse), when the equality of the Pzad and Uoc signals is violated with a functioning electric drive speed control system,

In case of short circuit or open circuit of speed feedback signal 1) ds

d Uc (t) is equal to zero, the reference signal /

second input of comparator 6

0

5

on the

dt

is zero, the speed controller (current setting unit 1) becomes saturated, the equality of the Shed and Uoc signals is violated, the comparator 6 switches to the single state and the key 4 is activated at the beginning of the transient process, which significantly reduces the path of the motor shaft and reduces the likelihood of emergency situations. Delay for (0.002-0.005) s. the delay provided by element 5 is necessary for detuning from switching interference when the drive is turned on and off.

Claims (1)

SUMMARY OF THE INVENTION A device for controlling an electric motor comprising a current setting unit, a current sensor, a current controller, a two-channel a key, a delay element, a comparator, first, second and third resistors, a threshold element and a speed sensor, the output of the current controller being the output of the device and the inputs connected to the reference unit current and current sensor, the closing contact of the key is connected between the output of the current regulator and the common bus of the device, and the breaking contact is between the control system of the power keys of the electric drive and a power source, the control input of the key through the delay element is connected to the output of the comparator, the first and second resistors are connected by one conclusions to the outputs of the unit for setting the current and current sensor respectively, and the second conclusions, combined into a common point, are connected to the first input of the comparator, the third resistor and the threshold element are connected in series by the first the output to the output of the current sensor, and the second to the first input of the comparator, characterized in that, in order to improve performance, the fourth resistor is connected in series, a capacitor and module isolation device, connected by the first output to the output of the speed sensor, and the second output to the second input of the comparator, the fifth resistor connected to the device common bus and the second input of the comparator.