SU1319226A2 - Electric drive with frequency-current control - Google Patents

Abstract

The invention relates to electrical engineering and can be used in industrial motion reproduction systems. The purpose of the invention is to expand the scope. This goal is achieved by introducing to the electric drive with frequency-current control an adder (C) 15, a reversible counter (PC) 16, a demultiplexer (D) 17, a zero-organ (BUT) 18 and a converter (FLL) 19 voltage - frequency . In addition, the current amplitude setting unit 4 is provided with an additional active current setting option connected to the HO 18 and FND 19 inputs. With 15 it is connected between the counter 9 and the register 10. The second input C 15 is connected to the output of PC 16. The control input D 17 is connected with the output BUT 18, the information input D 17 with the output of the FP 19, and the outputs with the inputs of the PC 16. The introduction of these blocks allows forming the slip frequency. Therefore, it is possible to control both synchronous and asynchronous motors. 4 il. I (L

Description

eleven

The invention relates to electrical engineering, namely, frequency-controlled electric drives, can be used in industrial motion reproduction systems for controlling synchronous and asynchronous short-circuited motors and is an improvement of the invention in accordance with the authors. 1279042.

The purpose of the invention is to expand the field of application by providing the ability to control both synchronous and asynchronous motors.

Figure 1 shows the functional diagram of the electric drive with frequency-current control; Fig. 2 is a block diagram of a current amplitude setting; FIG. 3 is a demultiplexer circuit; Fig. 4 is a diagram of a frequency matching unit.

The electric drive with frequency-current control (Fig. 1) contains a motor (D) 1, on the shaft of which a rotor position sensor (DP) 2 is installed, a phase current amplifier (UFT) 3, connected to the windings of the motor 1, and the control inputs to the outputs of the current amplitude setting unit (BZAT) 4, the reference frequency generator (HRC) 5, the output of which is connected via the frequency matching block (BSN) 6 with the input of the rotor position sensor 2, the initial phase setting unit (BSNC) 7 connected to the output from the inputs of the phase mixing unit 8, the other input of which is connected n to the output of the rotor position sensor 2, a counter 9 connected by the input to the output of the choke 5, and an output connected to the first input of the register 10, the second input of which is connected to the output of the phase-shifting unit 8. The output of the register 10 is connected to the inputs of permanent memory (ROM ) 11 and 12, programmed according to the laws of sinusl and cosine, respectively. The outputs of the ROM 11 and 12 are connected respectively to the inputs of digital-to-analog converters. (DAC) 13 and 14, connected by outputs to the reference inputs BZAT 4.

An adder 15 with two inputs, a reversible counter 16, a demultiplexer 17 with control and information inputs, a zero-organ 18 and a voltage-frequency converter (BFR) 19 are introduced into the frequency-current-controlled electric drive. BZAT 4 is equipped with an additional output current reference current connected to inputs

92262

the zero-organ 18 and the PNC 19, while the adder 15 is connected on the first input and output between the counter 9 and the register 10, the control input of the demultiplex of the plexer 17 is connected to the output of the zero-organ 18, the information input - on the output of the PNC 19, and the outputs - with the inputs of the reversible counter 16, the output connected to the second input of the sum of the torus 15.

BZAT 4 contains the driver of the tasks of the phase currents (FEFT) 20 (FIG. 2) with information and reference inputs and setters of the active 21 and reactive

5 22 components of the motor current 1, the outputs of which are connected to the information inputs of the FZFT 20. The reference inputs of the FZFT 20 form the reference inputs of the BFTA 4, the main outputs of which

0 are the outputs of FPP 20, and the additional output of the active current setting is the output of the active current setpoint 21.

Demultiplexer 17 for two outputs

 It can be built on the basis of elements And 23-26 (fig.Z). The control input of the demultiplexer 17 is formed by the inputs of the element And 23, and the information input - by the inputs of the element And 24.

30 The inputs of the And 25 element are connected respectively to the outputs of the And 23 and 24 elements, and the inputs of the And 26 element are connected respectively to the output of the And 24 element and to the inputs of the And 23 element. The outputs of the demultiplexer 17 are formed by the outputs of the And elements 25 and 26.

BSC 6 can be performed according to a scheme containing a frequency divider 27 (FIG. 4), a counter 28, and

0 mines are the devices (ROM) 29 and 30, each of which is connected in series with the corresponding DAC 31 and 32. The inputs of ROM 29 and 30 are combined and connected to the output of the counter 28, with 45 of the frequency divider 27 connected to the output. The input of the frequency divider 27 forms the BSh 6 input, the output of which are the PAP outputs 31 and 32. The frequency divider 27 can be assembled on digital integrated circuits, for example, according to a circuit made on the basis of a dynamic D-flip-flop.

The electric drive with frequency-current control works as follows:

55 som.

The stator windings of the engine 1 (which can be used as a synchronous or asynchronous motor, multi-pole or with

by magnetic reduction) are fed by currents from UFT 3. GOCH 5 produces square-wave pulses that simultaneously nocTynarot to the input of counter 9 and to the input - 6, in which the frequency divider 27 is divided by the frequency divider 27, where p is a coefficient equal to the number of pole pairs of the engine 1. A pulse sequence from the output of splitter 27 frequency with frequency f # / p is fed to the input of a cyclically functioning counter 28, which forms at its output a periodic sequence of numbers in binary code defining the addresses of words write it down ROMs in ROMs 29 and 30 according to a given switching table, ROMs 29 and 30 contain preliminarily tabulated values of the sine and cosine functions, respectively. The encoded values of these functions from the output of the ROM 29 and 30 are fed to the D / A converters 31 and 32, where they are converted into analog signals. Thus, at the output of the BSC 6, the required two-phase system of sinusoidal voltages is formed to ensure the position sensor 2 in the phase shifter mode. Frequency of these ex

SRI is equal to where N is the number

P-2 bits of the counter 28.

The output voltage of position sensor 2 is determined by the extrusion

V4 ..- n (

where a is the number of the counting pulse at the output of the counter 28,, 2, 3, 4, ..., 6 is the angle equal to the mechanical angle between the axis of the primary winding of the position sensor 2, fed nap. , 211 f, are. u ,. . (- 2N g) axis

output winding.

in time t

uk5 + c) 2

21lf

where, 1,2,3, ..., i.e. at the moments of changing the sign of the voltage U from negative to positive, the output of the phase-shifting unit 8 is formed

narrow interrogation impulse coming

the reference input of the register 10. In this case, the register 10 records information from the output of the adder 15, in which the summation of the codes of numbers

with fO f5 20 25 0

35

from the output of the reversible counter 16 and from the output of the counter 9, which converts a sequence of pulses with a frequency f from the output of the woofer to a sequence of numbers in binary code. Since the counter 9 functions cyclically, the same number at its output repeats itself through an interval of time T –r, where L is the number

1 bit

This periodic sequence of numbers goes to the first input of the adder 15, where it receives a phase shift determined by the time at each time with the number from the output of the reversible counter 16 present at the second input of the adder 15. After the end of the polling pulse of the register

10Save information about the state of the output bits of the adder 15, corresponding to the time t before the arrival of the next polling pulse.

From the output of register 10 with a frequency corresponding to the pulse frequency from the phase-shifting unit 8, the coded numbers are received at the inputs of ROM 11 and 12, each of which determines the address of the corresponding word recorded by ROM 11 and 12 according to a given switching table. ROM

11 and 12, the pre-tabulated values of the sine and cosine functions, respectively, are recorded. The encoded values of these functions come in PAP 13 and 14, where

analog signals of the following form:

N

Q and and. 2KT1 + 01N 2 -I. (2) 3 te C2 -2 iTf J

0

HS

Q

five

 „,“ Eosl | S 2S | iflE-2.4. (3)

where If is the phase shift of the voltages U, U, determined at each instant of time by the number at the output of the reversing counter 16.

In case of equality, the bits of counters 9 and 28, these voltages take the form (rv + H + 2Cr-P); (4) and cos (pQ + 4 + 2Kp JT). (five)

four

Voltages, U are fed to the reference inputs of BZAT, at the outputs of which voltages are generated, I specify. currents in the motor windings 1. If the motor windings 1 are two-phase, these voltages are

and, U cos (p0 + 4H-2KpIl) -UQsin. (+ if + 2Kp3r) (6)

Uq U .. s in (pv-t f -2KpJf) (pe + + C + 2KrL),. (7)

where Ug, Uj are the voltages of setting the active and reactive components of the motor 1, taken from the outputs of the sensor 5c of the active 21 and reactive 22 (Fig. 2) components of the motor current t, respectively.

In the case of the application of the go-phase motor 1, the block A for setting the current amplitude is supplied with a converter of the number of phases, and the amplifier 3 phase currents

It is also filled with t-phase. I ...

When an asynchronous motor is used in an electric drive, the code at the output of the reversible counter 16 changes with a frequency determined by a given slip frequency, which is formed in proportion to the voltage UQ. The voltage UQ is transformed into LF 19 into rectangular pulses with a frequency fn, arriving at the information input of the demultiplexer 17, the control input of which receives a signal sign Ug, formed by the zero body 18 and carrying information about the voltage sign U. With a positive f 2

served

 and the output of the demultiplexer 17

at the input of the forward count of the reversible counter 16, and with a negative U (3 - at the countdown input of the reversible counter 16. From the output of this counter, a sequence of numbers with a frequency f is removed. The sign

when t corresponds to a direct code change (an increase in the number at the output of the reversible counter 16 with the arrival of a counting pulse), and a sign corresponds to a reverse code change (decrease at the output of the reversing counter 16 with the arrival of a counting pulse).

The up / down counter 16 functions cyclically, with a repeat period of 2

No code at output T, where S is the number of bits of the reversible counter 16, equal to the number of bits of counters 9 and 28. The repetition period of code T corresponds to a phase change of 2iT. For any

Voltage U,

b - number

time points where

e

counting pulse at the output of the reversing counter 16, the angle defining

the phase shift of the voltages U, Uv, can be found according to the expression

i ± 22Lfjz

(eight)

Where

. the value of the angle is h at f 0. Consider that 0 23 fjp- t + G, where fgp is the rotor speed of the engine 1; 6 value of angle b at fgp 0 and. taking into account (8), expressions (6), (7) for the K-th moment. . samples take the form.

.cosL23Tp (f ± f

five

(f

TO

9Р

(f

0

fc) ± f.)

 3

(9)

ftf

+ U (f, ± f), (10)

Where

Q

- fa.

o

5. The set slip frequency, the voltage frequency from the output of DP2 (sampling frequency), YHH - - + 0 + 2Kr P;

Expressions (9), (10) are equivalent to d expressions for lattice functions obtained by time quantization with frequency f.jS of the stresses

five

, () sinL2Kp (f p ± fJt +; (11)

and and. sin 2jip (f, p ± f,)

+ U, (fgp ± f,) t + y. (12)

With no

SRI Uf

frequency ratio

.fc

may be

time fj and frequency; , UQ current, which is almost always reached, the voltage U., Ug can be represented as (11), (12).

 In this case, in the windings of the motor 1, using the phase current amplifier 3, sinusoidal currents are formed, the amplitude of which is determined by the signals

Ugi

and ... with the output of the active dial

; 21 and the reactive 22 component currents of the motor 1, and the frequency — the product of the number of pole pairs of the motor 1 and

0

the sum of the rotational speed of the rotor of the engine 1 and the slip frequency set in proportion to the voltage UQ.

When controlling a synchronous motor, the transmission coefficient of the FNP 19 is set equal to zero so that at any voltage UQ the frequency f 0. At the same time, the frequency of the currents in the windings of the motor 1 is determined as 713

The rotation frequency of the rotor and the number of pole pairs of the engine 1.

Thus, the introduction of an adder, a reversible counter, a null organ, a voltage-frequency converter, and a demultiplexer into an electric drive with frequency-frequency control of an alternating-current motor makes it possible to form a slip frequency and, therefore, use the electric drive to control both synchronous and asynchronous motors, i.e. allows you to expand the scope of application of the known electric drive.

Claims (1)

Invention Formula Electric drive with frequency-current control aut. St. 1279042, characterized in that, in order to expand the field of application " at 22 % 92268 neither by providing the ability to control both synchronous and asynchronous motors, an adder with two inputs is introduced into it, a reversible counter, a demultiplexer with control and information inputs, a zero-organ and a voltage-frequency converter, and the current amplitude setting unit is equipped with additional The zero output of the active current, connected to the inputs of the zero-organ and the voltage converter, is the frequency, while the adder on the first input and output is connected between the f5 by a switch and a register, the control input of the demultiplexer is connected to the output of the null organ, the information input of the demultiplexer — with the output of the voltage converter — the frequency, and 0 outputs - with the inputs of the reversible counter, the output connected to the second input of the adder. Wj and / 20 2 Sign L / o ti L. P. , Editor A. Sabo Compiled by A.Zhilin Tehred Z. Kadar Proofreader M. Sharoshi Order 2526/53 Circulation 660 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4 L ABOUT one Fig.Z FIG.