SU1399878A1 - D.c. electric drive - Google Patents

Abstract

The invention relates to electrical engineering and can be used dp speed control of electric motors. The chain of the invention is reliability. The device contains large-scale amplifiers 12, 13, 14, the outputs of which are connected to the input of the comparison unit 15. The output of the comparison unit 15 is connected to the input of the sampling-storage device 16. The second input of the sampling-storage device 16 is connected to a clock pulse generator 17. In this electric drive, transient processes are optimal in speed, both in the stepwise and in the linear setting of the rotational speed. 1 il. §

Description

This invention relates to electrical engineering and can be used in direct current drives.

The aim of the invention is to increase reliability.

The drawing shows a diagram of the drive.

The electric drive contains serially connected task unit 1, speed controller 2, limiter amplifier 3, core current regulator 4, controlled converter 5, electric motor 6, rotation speed sensors 7 and core current 8 connected to the inputs of the corresponding regulators. The speed controller 2 contains a differentiating element 9 connected to the output of the speed sensor 7, the first comparison node 10, the inputs of which are connected to the first output of the job block 1 and the rotation speed sensor 7, the second comparison node 11, the inputs of which are connected to the second output of the task block 1 and the output of the differentiating link 9, the outputs of the first and second comparison nodes are connected to the inputs of the first 12 and second 13 scale amplifiers, respectively, and the output of the core current sensor 8 is connected to the input of the third scale amplifier 14, the scale outputs Amplifiers are connected to the inputs of the third comparison node 15, the output of which is connected to the input of the sampling-storage device 16, the output of which is connected to the input of the amplifier-limiter 3, the control input of the sampling-storage device 16 is connected to the output of the 17 clock pulse generator.

The drive works as follows.

In the established modes, the voltage at the output of the third node 15 is proportional to the static load on the shaft of the electric drive:

50

sg), (,)

voltages corresponding to the set and set value of the rotation speed (

about )

voltages corresponding to the specified and steady-state value of the derivative of the rotational speed, i.e. acceleration (0); i. - the steady-state voltage value of the current core sensor, determined by the static load on the shaft of the electric drive;

К ,, К, Кз - constant transmission coefficients of large-scale amplifiers 12-14.

The 17-clock pulse generator produces short pulses with a T following period (10-50 ms for industrial electric drives), transferring the VHD for a short time (up to several microseconds) to the sampling mode. Thus, the output voltage of the sampling-storage device and the amplifier-limiter 3 , Which is the voltage setting of the current core, is a time-quantized signal

and. ,, (k) k, (k) -:) (k) + k) (k) -:) (k)),

in steady state proportional to the static load of the actuator:

K, i

st (k).

With a stepwise increment of the rotational speed reference (0) and a static load unchanged, the closest pulse from the 17 clock pulse generator puts the sampling-storage device 16 into the sampling mode and a voltage appears at its output

  K,:) (0) -:) (0) + + K, 1 (0),

where (0), (0), i (0) are the voltage settings of the speed, real speed and current of the core, measured immediately before the arrival of the first pulse from the clock generator.

The core current clears the setpoint with some inertia, determined by the time constant of the current loop.

When the next pulse arrives, a voltage is generated from the clock pulse generator at the output of the sampling-storage device 16.

(1) K, d (1) -d (1)) - K, 1 (1)

where (1), - (1), - (1), 1 (1) are voltages

the speed setting unit 1, the differentiator 9 speed sensor 7 and the core current sensor 8, measured immediately before the second pulse of the 17 clock pulse generator.

The transfer coefficients of the first and second large-scale amplifiers

In the first control interval, the output voltage of the sample-storage device 16 has the following meaning:

Uy ,, (0) K (0) - (0) h-K, 1 (0),

the second is determined according to the expression

. (,;) (1) - (1) + к, (1) (1) + Kji (1)

and on the third and subsequent

)

and,

Those. for two control intervals, the electric drive goes into the established dynamic mode, in which iijeT is the core current proportional to the specified acceleration of the electric drive.

Thus, the proposed electric drive allows one to obtain transient processes with optimal speed both with a stepwise and a linear specification of the rotational speed. In this case, the contour of the current core has inertia and is represented by a link of the first order, and as a controlled converter

are chosen such that by the end of the second the phase control thyristor converter will be used. The first-order astatism in terms of driving effects is the possibility of using commercially available thyristor converters to significantly expand the functionality of the electric drive, and the simplicity of its implementation contributes to its reliability.

40

45

The control current cycle has reached the steady state, and the rotational speed has reached the specified value.

If the voltage increment v of the speed reference is large enough, then the current in the transient enters the limit mode, the level of which is set by the amplifier-limiter 3. The motor speed increases linearly until the speed regulation error decreases to such a value, whereby the output voltage of the sampling-storage device 16 will become less than that limited by the amplifier-limiter 3. The current and the motor speed and speed of the engine at the same time for two control intervals reach the specified set eniy.55

With a linear change in the driver action, from block 1 of the task, on the speed controller 2, two signals are received that are not equal to zero: -5 O, S 0.

Claims (1)

Invention Formula A DC motor containing a motor connected to the output of the converter, and a series-connected reference unit, a speed controller, an amplifier-limiter, a current controller whose output is connected to the converter input, current core and rotation frequency sensors, whose outputs connected to the inputs of the corresponding regulator, the speed controller includes a differentiating element connected 35 40 55 45 55 Invention Formula A DC motor containing a motor connected to the output of the converter, and a serially connected reference unit, a speed controller, an amplifier-limiter, a current controller whose output is connected to the converter input, current core and rotation frequency sensors whose outputs are connected to the inputs of the corresponding regulator, the speed regulator includes a differentiating element connected the input to the output of the rotation speed sensor, the sampling storage device, the first and second comparison nodes, the inputs of the first comparison node being connected to the first output of the task block and the output of the rotation speed sensor, characterized in that, in order to increase reliability, the first, second and third large-scale amplifiers, the third comparison node and the clock pulse generator, the inputs of the second comparison node being connected to the second output of the reference block and the output differentiating the outputs of the first and second comparison nodes are connected to the inputs of the first and second scale amplifiers, the output of the current sensor core is connected to the input of the third scale amplifier, the outputs of the scale amplifiers are connected to the inputs of the third comparison node, which is connected to the input of the sample storage device which is connected to the input of the amplifier limiter, the output of the clock pulse generator is connected to the control input of the sample-hold device.