SU1267580A1 - A.c.electric drive - Google Patents

Abstract

The invention relates to electrical engineering and can be used to drive automatic manipulators, autonomous integrated robots, and the like. The purpose of the invention is to improve the accuracy of regulation. This goal is achieved by introducing a second measuring winding (O), which, together with the first measuring O, is connected to the output of a high frequency gir. This makes it possible to more accurately separate the signal proportional to the CKopoc-fH of the engine and use it in the speed feedback loop, which leads to an increase in control accuracy. The device contains a comparison element 6, a conversion unit (B) 5. B 4 controls, a 3 frequency converter, the output of which is connected to the stator O, two measuring O, (L connected to the output specified from r-th and to the input B 7 feedback. B 7 contains a filter 12, a demodulator 13 and B 14 for the speed distribution. 4 Il.

Description

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The invention relates to electrical engineering and can be used to drive the mechanisms of automatic manipulators, autonomous integrated robots, and so on.

The aim of the invention is to improve the accuracy of regulation 51 speed

FIG. 1 is a block diagram of an electric drive; in fig. 2 and 3, the arrangement of the measuring windings and the replacement circuit of the rotor and additional windings, respectively, in FIG. 4 - output signal of the high-frequency filter and amplitude-15 and

demodulator.

The current nepei-ieHiioio electric drive contains a squirrel cage rotor with a three-phase power and the first measuring winding; gmi 1 and 2 on the stator, frequency converter 3 with control unit 4 conversion unit 5 with input and three codes, comparing element 6, return unit 7 zi The three-phase power winding 1 of the asynchronous motor is connected to the output of the converter 3 watches, I control the input of which is connected to the output of the control unit 4, the inputs of which are СД1сл: very suitable for the corresponding output of the conversion unit 5, one input / output of which the output of the comparison element 6, and the other input - to the output of the feedback unit 7, one 13 of which is connected to, oh, the output of the first measure

 entry elements and framing

netgl connected to for. speed, and the other input, 1, - to the code of the feedback unit, second meter winding 8, high frequency generator 9, two isolation resistors. a and 11, feedback unit 7 is connected. filter 12 high frequency, ay. a chip demodulator 13 and a speed calculation block I1, the output of which is the output of the feedback block 7, two inputs of which are the inputs of high filter 12, frequencies), one output of the second measuring winding 8 is connected to the Drupp; the output of the first measuring winding 2 and grounded, the other output of the second measuring 1-pel1-nd winding; - 8 g connected to the other input of the feedback unit 7 and through the first section

The body resistor is 10 to one output of a high-frequency generator 9, the other output of which is connected through one second separation resistor 11 to one output of the first measuring winding 2,

FIG. 4 the following notation is taken: 15 and 16 - voltage at the outputs of the high-frequency filter; 17 and 18 - voltage on the outputs of the amplitude demodulator.

The drive works as follows.

At a signal to set the speed of SO,

6 comparison generates a difference signal Ato, which is fed to the first input of the conversion unit 5, which converts), as well as the LO signal fed to its second input, to the set of the emulation task signals and the frequency l. and the phases of the stator supply current. According to these signals, the control unit 4 generates the control signals of the power circuit of the converter 3, to the output of which are connected the phases A, B and C of the three-phase power winding 1 of the induction motor. In addition, the measuring windings 2 and 8 are fed through separation resistors 10 and 11 from a high-frequency generator 9 V1 1. The high-frequency voltage from the windings 10 and 11, together with the low-frequency components emitted by them, emf is fed to the input of the high-frequency filter 12, in which you target high-frequency spgnals 15 and 16 (Fig. 4), the mod: shredded teeth .sh pulsations. Amplice demodulator 1–3 descends sine and cosine envelopes 17 and 18 (Fig. 4), proportional to sine and cosine of the rotor angle, which produces a feedback signal on speed O in block 14 (Fig. 1) calculating speed.

The signal O is obtained as follows. Each measuring winding 2 and B and a short-circuited turn of the lateral surface of the rotor can be represented as a transformer with variable mutual inductance (Fig. 3).

To simplify, suppose that the coupling coefficient of the short-circuited coil and any measuring winding 2 and B varies from 0 to 1. The feedback signal O is the element

m

about 1, (1)

TO

4 иТ | Г where K is the coupling coefficient; M - mutual inductance; LI is the inductance of the measuring winding; LII - inductance of a short-circuited coil. Then the equivalent complex input impedance of such a transformer is gi. xi mg ..T4i where E is the output voltage of the high-frequency generator; measuring winding current active resistance in the measuring winding circuit; active resistance of a short-closed loop; circular frequency of the generator. If we ignore the active resistance of a short-circuited coil: and the active resistance in the circuit from the measuring winding is focused on the separation resistor, then the voltage on this winding will be determined by the suppression (I-K) Rl + jcaL | (IK) a amplitude of the high frequency envelope U1 lU11 tOi.Ll (IK) Since all the values in (4) except K do not depend on the angle of rotation of the rotor, it is possible to choose the shape and arrangement of the measuring windings, t. e. the dependence of the coupling coefficient on the angle of rotation of the rotor, so that the high frequency current envelope is sinusoidal or cosineusoidal. In particular, if we put in (4 R1 ЦЬ then at 2ЬП (Х (6)

(1 + cosnc),

Claims (1)

2 12 where o (- angle of rotation of the shaft dvpgatep - number of short-circuited turns of the rotor. A signal proportional to the angle is obtained similarly when the second measuring winding is positioned with a 1 / A shift of the period of the short-circuited turn of the lateral surface of the rotor. In block 14, the velocity is calculated using one of the known methods , for example, by the ratio 1., dydx, .n dt-y dF X СО8ПЙ.у SinCX Thus, due to the introduction of the second measuring winding, feeding a high frequency signal to both indicated windings and the Subsequent processing of these signals in the processing unit accuracy of speed control of an electric drive is improved.Application of the invention An alternating current electric drive comprising a squirrel cage rotor motor with three-phase power and a first measuring winding on the stator, a frequency converter with a control unit, a conversion unit with two inputs and three outputs Comparison element, feedback unit, three-phase power winding of the asynchronous wiggler is connected to the output of the pre-converted frequency, the control input is cheaply connected to the output of the ka the management, the inputs of which are connected with the corresponding 1C11 to the outputs of the transformation. One input is connected to the output of the control element, and the other input is connected to the output of the feedback loop, one input is connected to one output of the first measuring winding, one input of the comparison element is connected to the speed reference, and the other input is connected to the output terminal feedback, characterized in that, in order to improve the speed control accuracy, a second meter is inserted into it