SU1283712A1 - Control system for electric drive - Google Patents

Abstract

The invention relates to automatic control and is characterized by high demands on accuracy and speed in a wide range of rotational speed control under conditions of a significant change in the parameters and characteristics of the electric drive. The essence of the invention is that a known electric drive control system comprising a serially connected speed controller and a speed controller, as well as a thyristor converter control unit and an electromechanical object, the output of which is connected to the second speed controller input, are connected in series to the first adder, integrator, the second adder and the relay element and the p-connected reference model and the block forming the error signal, the output of which is connected to the second input of the relay The element, the inputs of the reference model and the first adder are connected to the output of the setpoint device, the second inputs of the first adder, the error signal generation unit and the second adder are connected to the output of the electromechanical object, output. The second adder is connected to the third input of the first adder, a mid-range filter is additionally introduced, the output of which is connected to the third input of the speed regulator, as well as a low-pass filter connected in series and an amplifier with adjustable output voltage limiting with the output of the speed controller, and the output with the control unit of the thyristor converter, the second input of the integrator and the input of the low-pass filter are connected to the output of the relay element, the output of the filter is low x frequencies are connected to the input of the mid-range filter. The invention can be applied in executive electric drives of CNC machines and manipula- tion cion robots. 1 yl. (L 1C 00 00 th

Description

1.12

This invention relates to automatic control and is intended

for use in permanent electric drive control systems

current, adjustable in speed of rotation, current and position, and characterized by high demands on the stability of their dynamic properties under conditions of a significant change in the parameters and characteristics of the electric drive.

The purpose of the invention is to increase the accuracy and speed of the electric drive control system.

The drawing shows a functional scheme of the proposed drive control system.

The control system contains a sensor 1, a speed controller 2, a block 3 for controlling a thyristor converter, a first adder 4, an integrator 5, a second adder 6, a relay element 7, a reference model 8, a block

9 formations of the error signal, filter

10 mids, low pass filter 11, amplifier 12 with adjustable output voltage limiting, electromechanical object

(not shown).

The control system works in the following way.

The driver signal from the setting device 1, implemented, for example, in the form of an adjustable divider with a constant voltage source or other setting of software rotation, through the speed controller 2 and the amplifier 12 with adjustable limitation of the output voltage and the post-thyristor converter control unit 3 It falls on an electromechanical object, which works it out with its dynamics. The speed controller 2 is implemented with a proportional-integral characteristic to impart astatism to the rotational speed control loop formed by blocks 2, 12, 3. The current controller, current sensor, thyristor converter and motor can be used as a unit of an electro-mechanical object. direct current with a rotation speed sensor (tachogenerator). The master signal arriving at the actuator is simultaneously applied to the reference model 8, implemented as a passive filter. At the output of the reference model 8, a signal is generated that corresponds to a steady 22

to a very fast transient process in an electric drive with a standard (intermittent) effect. Simultaneously, the signal coming from the output of the electric drive (tachogenerator), proportional to its output coordinate (speed of rotation of the engine), together with the output signal of the reference model 8, goes to the error signal generating unit 9, the output of which is the error signal between the reference transient, produced by model 8, and the real transition process of an adjustable electric drive. The signal at the output of the error signal generating unit 9, by its shape, duration and amplitude, characterizes the degree of deviation of the actual transient process from the reference one with a wide variation in the parameters and characteristics of the electric drive, for example, when the engine inertia moment changes during its replacement, which leads to a corresponding change in the gain in the control loop output coordinates, as well as when operating in the mode of intermittent currents and when load changes. In addition to the error error signal generating unit 9, the electric drive control device includes an object state estimation generating unit generating an estimate of the error error error and consisting of the first adder 4, the integrator 5 and the second adder 6 sequentially connected. The output proportional to the second adder 6 is outputted the rate of change of the error signal of the real and reference processes. Developed by the second

adder 6, the signal is applied through

I

the second input of the relay element 7 and

summed with the error signal of the match. The output of the relay element 7, in contrast to the prototype, is closed to the inverse input of the integrator 5, so that an internal correction circuit of the object forming unit is formed. In this circuit, a high-frequency switching mode (real slipping mode) with a frequency of 10 kHz is formed, which provides a refined, taking into account changes in the parameters of the electric drive, estimates of the derivative of the error of the error when, for example, the parameters of the engine change due to the moment of inertia brought to the motor shaft or replacing the engine or changing the excitation flow.

Thus, the work of the unit for forming an assessment of the state of an object, calculated on the linearity and immutability of the parameters of the object, is consistent, i.e. coincides with the motion of a non-linear electric drive with varying parameters. At the same time, the output signal, removed from the output of the relay element 7 and processed by the newly introduced low-frequency filter 11, is an adaptation signal that is fed to the inverting input of the input amplifier 12 with adjustable limiting output voltage, which increases the range of stable operation of the electric drive, and therefore, gives a further increase in its speed. The low-frequency filter 11 serves to averaging the signal from the output of the relay element 7, as well as for distributing the correction process of the electric drive condition evaluation unit and the electric drive adaptation process over time when its parameters and characteristics change. Additional insertion of amplifier 12, summing the signals from the output of the regulator 2 and the low-frequency filter 11, makes it possible to increase the accuracy of the electric drive at low levels of the input signal by eliminating the zero drift of the operational amplifier of the relay element 7, since amplifier 12 is inside the loop the NIL is regulated by the frequency of rotation formed by blocks 2, 12.3, and the presence of proportional-integral speed regulator 2 makes the drive static. The newly introduced connection connecting the output of the low-frequency filter 11 and the inverting input of the regulator 2 through the filter 10 mid-frequency, allows to increase the dynamic accuracy of the electric drive (reduce the overshoot), especially

the upper control range of the rotational speed of the electric drive, due to the coverage of the entire control loop of the electric drive, the dynamic component of the adaptive signal (the constant component of the adaptive signal is cut off by the filter 10).

Thus, the combination of newly introduced blocks and links increases the accuracy and speed of the electric drive under conditions of a significant change in parameters and characteristics.

Claims (1)

Invention Formula An electric drive control system comprising a thyristor converter control unit connected in series, an electromechanical object and a speed controller, a serial control unit, a first adder, an integrator, a second adder and a relay element connected in series. A reference model and an error signal generating unit connected by an output to the second the input of the relay element, the output of the electromechanical object is connected to the second inputs of the block forming the error signal, the first and second sum mators, the third input of the first adder is connected to the output of the second adder, the output of the setpoint is connected to the input of the reference model and the second input of the speed regulator, characterized in that, in order to increase the accuracy and speed of the system, it contains a medium-frequency filter and serially connected a low-pass filter and an amplifier with adjustable output voltage level, connected by an output to the input of the control unit of the thyristor converter, and a second input to the output of the speed regulator, the output of the relay element is connected to the second input of the integrator and the input of the low-pass filter, the output of which is connected to the third input of the speed controller through a medium-pass filter.