SU1385213A1 - Controlled electric drive for low-speed production equipment - Google Patents

Abstract

The invention relates to electrical engineering. The aim of the invention is to increase the range of speed control and increase energy performance. This goal is achieved by the fact that in a regulated electric drive for low-frequency technological equipment, the rotor winding of the arc-voltage motor is multiphase and is composed of sections 6, 7, 8.9 evenly distributed around the circumference of the rotor. The ends of the sections are connected by bridges 18, 19, 20, 21 of a material with low resistivity and bridges 22 of a material with high resistivity. In order to control the rotational speed, the winding leads of the articulator are connected to the network via keys controlled by the control unit. A rectifier and an inverter are used to return energy to the grid at lower speeds. 8 il. (Q (L

Description

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The invention relates to an electric drive, in particular to an arc-type electric drive, and can be used in the quality of a gearless electric drive for p personal technological equipment, i.e. low-speed and low-speed chemical equipment.

The purpose of the invention is to increase the range of rotational frequency control and increase energy performance.

FIG. 1 is a block diagram of an arcuate electric drive; 2 shows an example of a control unit; 3 (a, b), 4 (a b) diagrams of currents B of the rotor phase at different angles of rotation relative to the arc switches and at different operating modes; 5,6,7 - mechanical characteristics of the electric drive, on equal operating modes; on fit, 8 — engine rotor design.

The electric drive contains an electric motor with two arc stators 1 and 2 (Fig.), Each of which is equipped with a three-phase winding with no new poles and a rotor 3 with a winding. The winding of the arc regulator 1 is connected to a three-phase network 4c with phases A, B, C. The stators are diametrically opposed with an equal air gap above the lateral surface of the rotor.

The winding 5 of the rotor 3 is made multi-phase, each phase of which is composed of a set of sections 6–9 (Fig. 8) uniformly distributed around the circumference of the rotor 3

The same conclusions 10, 11 and 12, 13 diametrically located sections 6, 8 and 7, 9 in each phase of the winding 5 are interconnected, and the opposite terminals 14, 15 and 16, 17 of the adjacent sections 6, 9 and 7, 8 are connected between pairs respectively jumpers 18, 19 and 20; 21 of low resistivity material. In addition, bridges 10, 13 and 11, 12 sections 6.9 and 7.8 are connected in pairs by jumpers 22 of a material with high resistivity, for example steel. Controlled switches 23-25 are inserted in the electric drive to connect the windings of the second arc switch 2 to phases A, B, C of the network 4, g control unit 26, and the bridge rectifier 27 and inverter 28 are sequentially connected between each other. Rectifier input 27 is connected

with

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with the terminals of the winding of the second armature 2, the output of the inverter is provided with leads for connection to the façade A, B, C of the network. The control inputs of the keys 23-25 and the inverter 28 are connected to the outputs of the control unit 26, the input of which is connected to the setting unit 29.

The control unit contains a comparator 30 (FIG. 2), the input of which is connected to the output of the setting device 29, to the information inputs of the analog switches 31 and 32, and the output of the comparator 30 is connected directly to the control input of the first analog switch 34, through the element HE 33 to the control the second input of the analog key 32 "to the inputs of the five control boards 34; the input of the sixth control board 35 is connected to the output of the first analog switch 31, and the inputs of the six control boards 36 to the output of the second analog switch 32,

The device works as follows.

In the initial position of the setting device 29, corresponding to the upper value of the angular velocity of the rotor 3 of the arc electric wire, the logic control unit 26 opens, using control signals, AC keys 23-25 that connect the network terminals of the control unit with its output terminals, etc. e. with the coil of the articulator 2. Thus, the articulators 1 and 2 are both connected to a three-phase network 4.

In this case, in the air gap of both arcing machines, a traveling magnetic field arises, closing along; the magnet wire of the arc distributor and the rotor steel F, and F (FIG. 3). The alternating current switches 23 to 25 are connected by their inputs to the output terminals of the control unit 26 in such a way that the arc voltage regulator 2 has two phases that the phase of the supply voltage is shifted compared to the arc voltage regulator 1 by 120, therefore the direction of rotation of the magnetic fluxes of the arc voltage regulators 1 and 2 opposite.

An alternating magnetic field F and F, induces in the winding 5 of the rotor 3 currents li and 1.

In FIG. 3, the arc voltage motor drive at the moment of time when the rotor 3 is in the a position, i.e., when equal parts of the rotor winding 3 are located directly against the arc switches 1 and 2, FIG. 3 conventionally shows one phase of the rotor winding 3: one part 37 of the winding 5 is against the arc regulator 1, the other part 38 of the winding 5 is against the arc regulator 2.

In this case, the current 1 flows through the first part 37 of the winding 5, the passage through the jumpers 22, closes in the second part 38 of the winding 5, Current I leads in the second part 38 of the winding 5, and the passage through the jumpers 22 closes in the first winding part 37 -5, At each instant, the directions of currents 1 and 1 coincide (Fig. 3).

As a result of the interaction of the rotating magnetic field F, with the current, a rotational moment M, directed towards the rotation of the magnetic field F, occurs. As a result of the interaction of the rotating magnetic field f with a current, a torque M appears, directed towards the magnetic field Fg. Due to the fact that the magnetic fields (and φ rotate in opposite directions, the torques M and Mg | applied to the rotor 3 fold, and it rotates under the action of the total moment with a synchronous angular velocity n °, due to the number of pole pairs 1 and 2. When the rotor 3 rotates by 90 ° - to the position b, when jumpers 22 are located against arcs 1 and 2 (FIG. 3), the current pattern in parts 37 and 38 of the winding 5 of the rotor 3 remains the same, eg the magnitude and magnitude of the torques is maintained. With the next rotation of the rotor 3 by 90 / he again occupies position a (fig.Za), then again position b, etc.

Since the total moment is kept constant, the rotor 3 rotates uniformly with a synchronous angular velocity. At the same time, the attractive attractive forces between the rotor 3 and the arc drivers 1 and 2 are equal to each other and are directed in different directions (the arc switches 1 and 2 are located diametrically

opposite with the same air gap over the lateral surface of the rotor) and, compensating each other, balance the rotor 3. The magnitude of the currents O and 3 depends both on the emf of arc regulators and the resistance of the circuit.

In this case, the resistance of a closed loop consisting of

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two equal parts 37 and 38 of the windings 5 and jumpers 22 are determined by the resistance value of the jumpers 22; their resistance is much higher than the winding wire, since they are made of a material with a higher resistivity.

Thus, if the jumpers 22 are made, for example, of steel, the characteristic of an arcuate electric drive in this case will be equivalent to the characteristic of an asynchronous electric motor with a steel rotor and have the form shown in Fig. 5.

The advantage of the soft characteristic lies in the large starting points and the possibility of a stable rotor type in the whole range of angular velocities from synchronous to zero. The fig. 3 shows the mechanical characteristic () of the electric drive with one arc regulator, the total characteristic of the (b) electric drive with two asynchronous arc stators. By changing the geometry of the jumpers 22 (cross section, length), as well as their electrically conductive properties, it is possible to select the necessary mechanical characteristic (c) of this electric drive for a particular type of process equipment - (FIG. 5), with maximum efficiency at the point of AC keys 23 - 25 (Fig. 1), for example, thyristor circuits with counter-parallel switching of thyristors can be used, passing in turn positive and negative half-waves of the supply voltage.

When the position of the setting head slider 29 changes in the direction of decreasing angular velocity n, logic unit 26 changes the firing angle of one of the thyristor pairs of an alternating current key 23-25, for example, key 25.

Since the other half-wave remains unchanged, an asymmetry of phase A of the supply voltage (inequality of half-waves) occurs, which, in turn, leads to the appearance of a constant component voltage in phase A acting on a rotating rotor with a current gain. The further the position of the asymmetry engine of the setting device 29 from the initial position, the greater the asymmetry of phase A, an increase in the proportion of the constant component in it, and, consequently, an increase in braking gain per rotor, which leads to a decrease in its angular velocity due to the soft mechanical characteristic (erne one advantage of the soft characteristics of the drive).

Consider the mechanical characteristic of the electric drive in this mode, Q 20, the second part 38 of the winding 5, the re-arc conditioner 1 is turned on, cross, directly, and the mechanical characteristic (and FIG. 6) of the drive has not changed.

The arc regulator 2 operates in the combined mode and acts on the rotor 3 with two forces: - the engine (a) and the brake (b) (Fig. 6). The total characteristic of the interaction of the stator 1 and the arc regulator 2 gives the mechanical characteristic (g) of the arcuate electric drive in the combined mode (fig 6) „

Thus, it is possible to change the angular speed of the rotor 3 from the synchronous 25 c arbor of 2, a torque M arises applied to the arc 20

sliver 19, in this case, the picture of the directions of the currents relative to the arcing machines 1 and 2 is preserved. As a result of the interaction of the rotating magnetic flux Φ and the current 1, a torque M occurs, directed in the direction of rotation of the magnetic field. The part 38 of the three-phase winding 5 of the rotor 3 generates a rotating magnetic flux F, which closes in the arc clamp 2, which induces a current in the windings of the arc splitter 2.

As a result of the interaction of the rotating magnetic flux φ and t velocity n ° up to a certain speed n, moving along the family of characteristics (e) to characteristics (g).

With the help of the described technical means, it is possible to further reduce the OQ angular velocity of the rotor (from 0.05 to Oj1 n), however, in this case almost all the energy consumed by the arc-2 will be used to maintain the braking gain and power characteristics of the drive will be low.

It is possible to consider the depth of adjustment of the angular velocity of the rotor 3 by the combined mode method of about 1: 3 (up to n 0.3 n °) to be considered optimal and economically. In this case, the efficiency of the electric drive will be no worse than 0.5.

With a further change in the position of the setting engine, the logic control unit closes the alternating current keys 23-25 and opens the inverter 28.

Thus, only arc switch 1 is connected to the network, the three-phase winding of which creates a twist

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stator-2 and directed towards the rotating magnetic flux. Since the arc regulator 2 is fixed

 motionless, the same moment acts on the rotating rotor 3 in the opposite direction, which coincides with the direction of its rotation. Thus, the rotor 3 is acted upon by the total driving moment M - M.; and it rotates at a low angular velocity (with a large slip) with respect to

angular synchronous speed magnetic field. The slip energy released in the rotor from the side of the douser 1 when creating the moment M is induced in the duster 2 when creating the moment KI and through the three-phase rectifier 13 (FIG. 1) and the inverter 14 returns back to the network. The characteristic of the drive in this mode will have the form shown in Fig.7. Changing the position of the setting engine 9 leads to a change in the proportion of energy returned to the network with the help of, controlled by the inverter 28 and, consequently, to the appearance of a family of characteristics (Fig.7), in. which can be lowered down to low and even creeping speed In this case, the electric power is consumed by one arc regulator 1, and the total moment is obtained double (M 1 – M0. Useful work in this case is Pr (M – M i) n.

Touch the magnetic flux. The alternating magnetic flux f, induces in the first part 37 of the winding 5 the same current 1 (Fig.4a). However, it now closes not through steel jumpers 22, but along the path of least resistance: jumper 18 to position a, 18, second part 38 of winding 5, jumper 19 — first part 37 of winding 5 (FIG. 4a).

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In the second part 38 of the winding 5, the current 1 now flows in the same direction as in its first part 37 (bottom to top). In the position (FIG. 4), the current is closed. By contour: the first part 37 of the winding 5, jumper 21, the second part 38 of the winding 5, jumper 18, the first part 37 of the winding 5, jumper

20, the second part 38 of the winding 5, re-

each of the arc regulator 2 occurs torque M applied to the arc

sliver 19, in this case, the picture of the directions of the currents relative to the arcing machines 1 and 2 is preserved. As a result of the interaction of the rotating magnetic flux Φ and the current 1, a torque M occurs, directed in the direction of rotation of the magnetic field. The part 38 of the three-phase winding 5 of the rotor 3 generates a rotating magnetic flux F, which closes in the arc clamp 2, which induces a current in the windings of the arc splitter 2.

As a result of the interaction of the rotating magnetic flux, f and

OQ,

35

40

45

50

55

stator-2 and directed towards the rotating magnetic flux. Since the arc regulator 2 is fixed

 motionless, the same moment acts on the rotating rotor 3 in the opposite direction, which coincides with the direction of its rotation. Thus, the rotor 3 is acted upon by the total driving moment M - M.; and it rotates at a low angular velocity (with a large slip) with respect to

angular synchronous speed magnetic field. The slip energy released in the rotor from the side of the douser 1 when creating the moment M is induced in the duster 2 when creating the moment KI and through the three-phase rectifier 13 (FIG. 1) and the inverter 14 returns back to the network. The characteristic of the drive in this mode will have the form shown in Fig.7. Changing the position of the setting engine 9 leads to a change in the proportion of energy returned to the network with the help of, controlled by the inverter 28 and, consequently, to the appearance of a family of characteristics (Fig.7), in. which can be lowered down to low and even creeping speed In this case, the electric power is consumed by one arc regulator 1, and the total moment is obtained double (M 1 – M0. Useful work in this case is Pr (M – M i) n.

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At very small values of n (at creeping speeds), the value is much less than the electric power consumed by the arcing unit 1 and all the electric power minus losses in the three-phase bridge 27 and the inverter 28 is recovered into the network.

The control unit (FIG. 2) operates as follows.

At the initial position of the setpoint slider 29, corresponding to the maximum angular velocity of the rotor of the drive, the comparator 30 turns on with its signal and switches the control board 5 and the control boards 4 directly through the analog key 31, which control the thyristors of the alternating current keys 23-25 through the HE element 34. The comparator. 30 turns off the analog key 32. In this case, the keys AC 23-25 are turned on and the rotor 3 rotates at a synchronous angular speed. Changing the position of the engine setting unit 29 causes the thyristor of phase 25 key A, which passes one of the half-waves, to be covered with an analog key 31 acting on the control board 35. The rotor 3 reduces its angular velocity due to the occurrence of braking gain. The setting control slider 29 causes the comparator 30 to close (at the moment corresponding to 3 n °) and, consequently, to close the control boards 34 and 35, i.e. switching off the alternating current keys 23–25. Through the NOT 34 element, the closed comparator 30 switches on the analog key 32, allowing it to be turned on via the control boards 26 of the inverter 28 and further controlled by means of the setting unit 29.

Thus, this electric drive has a greater angular velocity control range (1: 1000) and, therefore, can be used as a gearless electric drive from high-speed equipment, which is evidence of the expansion of its functionality. At the same time, the energy characteristics of the electric drive at nominal and low revs are improved, which is reflected in an increase in the PDC at nominal revolutions due to the rotor being balanced by the diametral installation of two arc controllers and at lower revolutions due to the rotor slip energy being recovered and a double moment is obtained. The power factor improvement is obtained by selecting the appropriate ignition angle of the inverter thyristors.

Claims (1)

Invention Formula Adjustable electric drive for low-speed technological equipment, containing an electric motor with arc stators, each of which has a multi-phase winding with implicit poles, the winding of one arc stator is provided with leads for connection to the network, and a rotor with windings that is characterized by the fact that increasing the frequency control range of the rotational frequency and increasing the energy indices, the rotor winding is made multiphase, each phase of the rotor winding is composed of four sections equal to rectangularly distributed around the circumference of the rotor, one-named conclusions diametrically located sections and one opposite conclusions adjacent sections of each phase of the rotor winding are interconnected by jumpers from a material with low resistivity, and other opposite conclusions from adjacent sections of the same phase are jumpers from a material with high resistivity, such as steel, and controllable keys are introduced to connect the multiphase winding of the second arc stator to the network, a control unit, a but interconnected by a bridge rectifier and an inverter, the input of the rectifier is connected to the terminals of the multiphase stator windings of the second arc, and the output of the inverter is provided with terminals for connection to the network control inputs decree OF DATA keys and inverter soe-: dineny yield control unit. -0GP d S with / f COP kb ka ka t t t t t t fr iii w u about j j / 5U 15 Well d five F Lzh 0t ../ . a) to f1 ffi 78  i / g 2 but 3 22 J g mi {7 22 3 38; with about Ml Fig.Z / V, FIG. FIG. five 2P P P Th 7