SU1026272A1 - A.c. electric drive - Google Patents

Abstract

AC power drive containing a short-circuited rotor asynchronous motor, the stator windings of which are connected to a direct-connected frequency converter, a rotation speed adjuster, the output of which is connected to the input of the stator phase current and the flow coupling of the rotor, which outputs through the phase regulators block connected to the control inputs of the frequency converter with a direct connection, the phase current detection unit with the phase current meters connected to the unit Calculate the flux linkage of the rotor, the three-phase output of which is connected to the corresponding feedback inputs of the phase regulator unit, the synchronization unit, the rotation speed detection unit with a speed sensor, the output of which is connected to the second input of the stator phase current setting driver and the rotor power difference, so that, in order to improve quality in dynamic modes of operation,. equipped with a discrete block of calculated coefficients and a discrete RAM block, the inputs of which are connected to the outputs of the phase regulator block, the phase current detection block and the rotation speed determining block, the first and second three-phase outputs of the discrete RAM block are connected to the first and second three-phase inputs respectively the rotor flow calculation unit, the third and fourth three-phase outputs, and the fifth output of the discrete memory unit - with the corresponding inputs of the discrete the locus of calculated coefficients, the first and second outputs of which (L ogo are connected to the corresponding inputs and controls of the phase adjustment block of the poTOpia computation unit, while the second three-phase output of the discrete random-access memory block is connected to the corresponding feedback input of the block phase regulators, and the phase regulator block and the rotor flux linkage computation block VO5 are complete in the form of multidisciplinary discrete transducers, the unit of definite currents is supplied with phase integral integral The light converters, the input of each of which is connected to the output of the corresponding phase current meter, and the output forms the corresponding phase output of the phase currents detecting unit, the unit for determining the rotational speed is equipped with an integrated analog-digital converter whose input is connected to the output of the speed sensor, and the output forms the output the unit for determining the rotational speed, with the synchronization inputs

Description

the analog-to-digital conversion and tokoe speeds are included

Phase Detectors

1026272

to the output of the sync block.

The invention relates to electrical engineering, in particular, to frequency-controlled asynchronous electric pilots and can be used in systems where the requirements are reliability and high dynamic properties, in particular, in the mechanism of the rotary wheel of an excavator.  An alternating current izvesgen alternating current motor containing a squirrel cage rotor asynchronous motor, the stator windings of which are connected to the output terminals of the frequency converter with a direct connection connected to the supply mains and connected to the stator current sensors, and the shaft is connected to the speed sensor.  Hall sensors are installed in the engine, the outputs of which, together with the outputs of current sensors, are connected to the control system through the coordinate converters and solvers, and the outputs of the latter through the coordinate converters are connected to the control inputs of the frequency converter with direct connection.  The control system of the known device is a two-channel subordinate control system.  One channel of stabilization of the flow vector module is made with a subordinate magnetizing current control loop, the second channel of motor speed control.  with a subordinate circuit regulating the active current of the motor.  The channels are interconnected by cross-links l.  A disadvantage of the known device is that the installation of the Hall sensor is associated with a change in the design of the electric motor.  The characteristics of the Hall sensors depend significantly on temperature, therefore, in order to make accurate measurements of the magnitude of the flux linkage, it is necessary to create a complex system of temperature stabilization.  In addition, since the drive is made on the basis of analogue technology, all decisive devices used to determine the harmonic functions, division, multiplication, are complex and unreliable devices that have,. computational error.  The closest to the proposed technical entity is an AC electric drive containing an asynchronous motor with a short-circuited rotor, the stator windings of which are connected to a direct-connected frequency converter, a rotational speed adjuster, the right side of which is connected to the first stator current currents and flux linkage, the outputs of which through the block of phase regulators are connected to the control inputs of the frequency converter with a direct connection, the block of sensors of phase currents with phase meters of currents associated with a block of coordinate transformations, the outputs of which are connected to the corresponding feedback inputs of the block of phase regulators, the block of compensating links and. the calculating unit, the rotational speed sensor, the output of which is connected to the BtopoMy input of the stator and stator phase flow setting unit 2.   The disadvantage of the known electric drive is its complexity and, accordingly, low reliability.  Since the control system of the device is continuous, it is based on the analog technique of non-linear conversion. bodies that associate absolute slip with engine torque are associated with a number of difficulties.  In particular, it is necessary to avoid piecewise linearization of nonlinearity, which makes the converter difficult to set up and has low accuracy. Difficulties arise in the implementation of coordinate transducers and a computational block, since the latter include multiplication, division, etc. d. , the implementation of which on the basis of analogue technology is conjugated with significant errors.  Increasing accuracy is associated with the complexity of computing devices.  The neglect of discrete properties of the frequency converter necessitates the introduction of additional current feedbacks, stabilizing its operation in a discontinuous current mode, which determines the need for introducing additional elements of the comparison and complicates the electric drive.  The indirect determination of the components of the flux linking vector in a known electric drive determines the need to install additional sensors for stator phase voltages, which also complicates the electric drive and reduces it. Its accuracy is high, since it requires solving the issue of galvanic isolation with a control system and at the same time maintaining a high accuracy of signal measurement.  In addition, in a known electric drive, there is no possibility of direct interfacing with digital computing units and various software programmers.  The purpose of the invention is to increase the quality in dynamic modes of operation and control reliability by adjusting the stator current frequency converter rutor and speed of rotation, averaged over a discrete interval of the frequency converter.  The goal is achieved by the fact that an AC electric drive containing an asynchronous motor with a short-circuited rotor, the stator windings of which are connected to a frequency converter. directly connected, the rotational speed sensor, the output of which is the keys to the first input of the shaper of the stator phase currents building and the rotor flux coupling, the outputs of which are connected to the control systems of the primer through a phased array of phase regulators. a directly connected timefothy timer, a block (phase currents with phase current gages, connected to the unit р s flux linkage unit, the phase output of which is connected to the feedback inputs (phase regulators, synchro unit Ou | vatsii, the unit for determining the rotational speed with a speed sensor, the output of which is connected to the second input of the | stalk phase setting current | And the rotor flux linkage, is equipped with an arithmetic unit of calculated coefficients and a discrete memory block, the inputs to Secondly, they are connected to the outputs of the phase regulator block, the phase current detection block and the rotation speed target detection block, the first and second three-phase outputs of the discrete memory unit are connected to the first and second three-phase rotor current coupling units, and the third and fourth three-phase, respectively. the outputs and the fifth output of a discrete memory unit - with the corresponding inputs of the ciscrete block of calculation coefficients, the first and second outputs of which are connected to the corresponding inputs and controlling the phase regulator unit and the rotor flux linkage calculation unit, while the second three-phase I output of the discrete memory unit is connected to the corresponding feedback input of the phase regulator unit, and the phase regulator unit and the rotor flux linkage calculation unit are in the form of multi-connected discrete converters, the phase currents determination unit is supplied by phase integrated analog-digital converters, the input of each of which is connected to the output of the corresponding phase meter current, and the output forms the corresponding phase output of the phase current detection unit, the rotation speed determination unit is equipped with an integrated analog-digital converter, the input of which is connected to the output of the speed sensor, and the output forms the output of the rotation speed determination unit, and the synchronization inputs of the integrated phase determination sensors currents and speeds are connected to the output of the synchronization unit.  FIG.  1 shows the functional scheme of the proposed AC drive; in fig.  2 is a functional diagram of a driver for setting stator phase currents and rotor flux coupling; in fig.  3 is a functional circuit of a frequency converter with direct communication.  The AC drive comprises an asynchronous motor 1 with a short-circuited Rutor (FIG.  1), the stator windings of which are connected to the frequency converter 2 with direct connection, the rotation speed controller 3, the output of which is connected to the first input of the shaper 4 sets the stator phase currents and the coupling pOTOpja, the outlets of which are connected to the control inputs of the pryozravatel 2 frequencies with non-temporal svyb  The electric drive contains a block 6 for determining the phase currents with phase meters 7 to 9 currents associated with the block Y of the rotor flow calculation, the three-phase you, which is connected to the corresponding feedback loops of the block 5 of phase regulators, the block 11 of synchronization and the block 12 for determining The speed of rotation with a speed sensor 13, the output of which is connected to the second input of the driver 4, sets the phase currents of the stator and the rotor flux linkage.  The AC drive is provided with a discrete block 14 of the calculated coefficients and a discrete block 15 of the RAM, the inputs of which are connected to the outputs of the block 5 phase controllers, block 6 for determining phase currents and block 12 for determining the rotation speed.  The first and second three-phase outputs of the discrete memory unit 15 are connected respectively to the first and second three-phase inputs of the rotor flux linkage calculation unit 10, the third and fourth three-phase outputs and the fifth output of the specified block with the corresponding inputs of the discrete coefficient coefficient unit 14, the first and second outputs of which connected to the corresponding control inputs of the block 5 phase regulators and block 10. calculation of the rotor flux linkage.  The second three-phase output of the discrete memory block 15 is connected to the corresponding feedback input of the block 5 phase controllers.  Block 5 of phase regulators and block 1O of the rotor flux linkage calculation are made in the form of multifunctional discrete transducers.  The phase current detection unit 6 is integrated with analog to digital converters 16-18, the input of each of which is connected to the output of the corresponding phase current meter 7-9, and the output is the corresponding phase output of the phase current detection unit 6.  The rotation speed determining unit 12 is provided with an integrated analog-to-digital converter 19.  The synchronization inputs of analog-to-digital converters 16 19 connected to the output of the synchronization unit 11.  The shaper 4 sets the phase currents of the stator and the rotor flux linkage contains a reference element 20 (fkg.  2) the channel for calculating the required average phase.  stator currents and the channel for calculating the required averaged phase rotor flux linkages.  The channel for calculating the required averaged phase currents of the stator contains a block 21 for calculating the required averaged moment of the electric motor 1, Bxdb of which is connected to the output of the comparison element 2O, and the output to one of the inputs of the averaging slip calculator 22 and simultaneously through one of the inputs of the averaging active calculation block 23 the stator current vector and the module 24 for calculating the module of the averaged stator current vector are connected to one of the inputs of the first vector converter 25.  At the same time, the second input of the module 24 for calculating the averaged stator current vector module is connected to the output of the 26 calculating block averaged reactive component of the stator current vector, which is simultaneously connected to one of the inputs of the angle calculator 27 between the averaged current vector of the rotor and the rotor flow, its second input is connected to the output of block 23 for calculating the averaged active component of the stator current vector.  The output of the angle calculator 2 7 between the averaged stator current and rotor flux current vectors through one of the inputs of the calculator 28 of the angle of rotation of the averaged stator current vector is connected to the second signal of the first vector converter 25, the outputs of which are connected to the corresponding circuits of the current setting of the 5 phase regulators .  The channel for calculating the required averaged phase rotor flux linkages contains a unit 29 for calculating the rotation angle of the averaged rotor flux vector vector, one input of which is connected to the output of averaging multiplication unit 22, the second to the output of the integrated analog-digital converter 19, the third to the output of the speed setpoint 3, and The code is connected to the second input of the unit 28 for calculating the angle of rotation of the averaged stator current vector and to the normal one from the inputs of the second vector converter 30.  The second input of the second vector converter AOR, the input unit 26 for calculating the averaged reactive component of the stator current vector and the second inputs for calculating unit 22 for calculating the averaged slip and block 23 for calculating the active average component of the stator current vector are connected to the output side of the rotor axis-displacement vector module 31.  The output of the second vector converter ZO is connected to the corresponding one. the chains of the blocking of the linking of the block of 5 phase regulators.  A non-first coupled frequency converter 2 contains a digital system 32 of pulse-phase control (FIG.  3), the control inputs of which are connected to the outputs of the block 5 phase regulators, the power input switches are connected to the power supply network, and the power inputs are connected to the control electrodes of the thyristors of the phase thyristor converters 33-35.  The power inputs of the phase thyristor converters 33 - 35 are connected to a three-phase mains supply, and the outputs are connected to the stator of an asynchronous electric motor 1 with a short-circuited rotor.  It should be noted that the units of the control system are digital devices based on microprocessor-based LSIs of the K-589 series.  The AC drive, current works as follows.  During operation, the instantaneous values of the rotor speed and stator phase currents from the outputs of the corresponding meters 7–9 phase currents and the speed sensor 13 are continuously fed to the inputs of integrated analog-to-digital converters 16–19, respectively, the analog parts of which are integral links.  In turn, the synchronization unit 11 produces synchro pulses, the instants of occurrence of which coincide with the natural commutation points of the phase thyristor converters 33 - 35 ,.  and the follow-up period is equal to the discreteness interval of the frequency converter 2 with the direct connection t. e.  the discreteness interval of its phase thyristor converters is 33 - 35, and the duration after the next is equal to the t-phase thyristor converter T —r -) where coO is the circular frequency n () t supply voltage integral analog digital converters 19, 16-18.  Upon arrival of the sync pulse information that has been accumulated up to this point, t. e.  during the elapsed time interval, it is read from the output of the integral analog-digital converters 19, 16-18, and is fed to the shaper inputs 4 phase tasks. the stator currents and the engagement of the rotor and the discrete memory unit 15 are recorded in them.  Thereafter, the contents of said integral analog-to-digital converters are zeroed out and hedgehogs begin to accumulate new information.  As a result, at the end of each discrete interval of the frequency converter from the outputs of the integral analog-digital converters 19, 16-18, information is read that is numerically equal to Ueb,; f j% mt. e.  averaged over the interval of discreteness of the frequency converter of the measured value.  As a result, at the end of the discrete interval of the frequency converter, information is read from the outputs of the integrated analog-digital generators 19, 16-18, numerically equal to the values of the rotor speed and stator phase currents averaged over the discrete interval, respectively.  These values, as mentioned above, are recorded in a discrete memory block 15, in which, in addition, the values of control angles of the frequency converter with direct communication from the outputs of the block 5 of different controllers are recorded at each interval of discreteness.  The values of the values recorded in the discrete memory unit 15 are stored for two discrete intervals.  Functionally, the electric drive control system is made as two-circuit: external - control circuit of the rotor speed averaged over the interval discretization; internal - adjustment of the averaged phase currents of the stator and rotor fluxes.  At the same time, the internal loop is optimal in speed and allows you to work out the specified values of the averaged phase currents of the stator and the rotor flux linkages in two discrete intervals of the frequency converter.  By virtue of this task, these values are given two forward intervals.  Consider the operation of the device from the beginning of the (P + 1) -th interval of discreteness of the 2 frequency converter with direct connection, assuming that the h interval ended up testing the previously set averaged phase stator currents, the rotor flux linkages and the speedy gyrator.  Setpoint 3 speed of rotation issues. the value of the required average rotor speed on the (n + 2) -th discretization interval (2.  The latter arrives at the input from the inputs of the comparison element 20, the second input of which, at the end of the I-th interval, receives the value of the measured average rotor speed in the n-th discrete interval to and from the output of the integral analog-digital converter 19.  Comparison element 20 determines the value of the difference between set to (AND + 2). 4l and the measured nap orm Discreteness averaged speeds.  This value comes from the output of the comparison element 20 to the input of the block 2 for calculating the required average motor torque, which calculates the average torque AL that the induction motor 1 should develop at (n + 1) -m and (tt + 2) -M intervals for in order to work out the specified value of the average speed on the (n + 2 | th interval of discreteness).  Block 21 implements the following functional link; Mei k 1 - 1-H1-pz) -, where kl is a constant coefficient depending on the parameters of the electric motor 1 The value of the required average moment comes from the output of block 21 to one of the inputs of block 22 for calculating the average slip, to the second input of which receives the value of the modulus of the averaged flux linking vector po «Topaltfpj from the output of the setting device 31.  Moreover, the module of the averaged rotor flux linkage vector I (t I is set by the setting device 31, based on the condition that it is maintained at a given level.  Block 22 determines the value of the average glide slip which must be maintained at (h + 1) -th and (n + 2) -th discrete intervals to ensure the required average torque of the electric motor 1.  Block 22 implements the following functional relationship: CO j.    Mae / (K2), where.  К2 is a constant coefficient depending on the parameters of the electric motor 1.  At the same time, the values of the averaged electromagnetic momentum Me from the output of the block 21 and the motions of the averaged rotor flux vector from the output of the setter 31 arrive at the input of the block 23 for calculating the averaged active-; component of the stator current vector.  The latter calculates the discrete averaged over the interval of the frequency converter of the active component, the stator current i, t. e.  orthogonal to the rotor flux linkage vector component of the stator current vector, which must occur in asynchronous motor 1 at (in-l) -M and (h + 2) -M intervals of discreteness so that the latter can develop the required average The electromagnetic moment Me-Block 23 realizes the following connection: ia GE / ().   CG is a constant coefficient depending on the parameters of the electric motor 1.  At the same time, the value of the modulus of the averaged rotor flux linkage vector is fed to the input of the averaged reactive calculator 26. component of the stator current vector.  The last implementation of the calculation is the discretization of the frequency converter J averaged over the interval: the active component of the stator current ip, t. e.  averaged parallel to the rotor flux linkage vector, the component of the stator current vector, which must occur in the asynchronous motor 1 at the) and (n + 2) -th discrete intervals in order to provide the specified module of the averaged rotor flux linkage vector, t. e.  set stream magnetizing motor 1.  Block 26 implements the following functional relationship: ip K4-lVrU where K4 is a constant factor depending on the parameters of motor 1.  The values of both averaged components of the stator current vector come from the outputs of blocks 23 and 26 to the inputs of block 24 for calculating the module of the averaged stator current vector.  The latter calculates the modulus of the said vector-, paligi, expression (At the same time, the values of both averaged components of the stator current vector arrive at the inputs of the angle calculation unit 27 between the averaged vectors, the stator current and the rotor flux linkage, which calculates the angle between the mentioned vectors (p, which should take place in the asynchronous electric motor 1 on (nI) -m and (n + 2) -th discrete intervals, using the following expression arct (Go, / Gy).   IN BRIEF, the required averaged rotor speed in the (n + 2) interval of ciscreteness of the frequency converter CO-23 from the output of the sensor 3 speeds of rotation, measured rotor velocity on the L-th interval of signals (3 "1 from the output of the integral analog-digital converter 19 and the reduced slip from the output of the averaged slip calculating unit 22 are fed to the inputs of the calculating unit 29 of the rotational angle of the cut-off rotor bearing vector, which calculates the required angular position and the averaged rotor flux-coupling vector on the (Ji + 2) -M interval of discreteness relative to the stator phase A using the expression pW + l WcK W tni l + ooWlT, memorize it, after which the obtained value is fed to one of the inputs of the calculated 28 stator current vector.  Block. 28 performs the summation of the required angle of rotation of the averaged rotor flux link vector over (ii + 2 relative cisternity interval). phase A of the stator with the required angle is between the averaged vectors of the stator current and rotor flow, and the value of which is fed to the second input of the unit 28 from the output of the unit 27.  As a result, block2 calculates the required angle of rotation of the averaged stator vector in the (P + 2) -th discrete interval relative to the stator phase A h 21.  4tp.  The output information of blocks 24 and 28 29 and setter 31 completely determines the averaging of the stator current vector and rotor flux on the (1I-2) -th discreteness chain.  The values of the module of the averaged vector of the stator current from the outputs of the block 24 vi its angular position on the (n + 2) -th discrete interval from the output of the block 28 arrive at c. moves of the first vector converter 25.  The latter calculates the direction cosines of the averaged stator current vector over the (tt + 2) -M discretization interval, after which it performs the determination of the required cut-off stator phase currents over the (n + 2) discreteness interval 1 -211,.   decomposition of the mentioned vector in the m phases of the stator.  Similarly, the values of the magnitude of the averaged rotor flux linking vector from the output of the setting unit 31 and the angular position on the (P + 2) interval of ciscreteness from the output of the unit 29 are located on c. the moves of the second vector transformer 30.  The last computational cosine of the averaged rotor flux linkage vector is on the (th + 2) th ciscreteness interval, after which it is necessary to determine the required averaged rotor phase flux linkage of the a (n + 2) th ciscreteness interval, by decomposing the said vector along o m phases of the stator.  The values of the calculated average phase currents of the stator, dp + 2, 5c Lti 21. -i zs and rotor flux linkages (.  VjcCl comes from the outputs of vector converters 25 and 30 in the reference circuit of the reduced stator phase currents and the rotor flux linkages of the block 5 phase regulators.  It should be noted that the definition of the square root functions in block 24, arctangent in block 27 and cosines in vector converters 25 and 30 is carried out in a tabular manner, t. e.  the values of the functions are pre-computed in the required range and recorded in the permanent storage devices with which the above-mentioned blocks and vector converters are provided.  Permanent XI + K4 coefficients are also precomputed for each specific electric motor and are recorded in permanent storage devices, which are supplied with. Loki’s wives are 21-23 and 26.  To calculate the control angles of the frequency converter 2 at (hH) -M and (P + 2) discrete intervals, it is required, in addition to information about the stator phase currents, to have information about the averaged phase flux of the rotor and the stator voltage in the P discrete interval are determined in the drive by calculation.  Calculations are averaged. x phase flow-. The rotor chain connections on the atomic interval of ciscreteness are performed by the unit 10 for calculating the rotor flux linkages by expression. jM W4C2j, j-A, B, C, | and. (,,. . Fs5r ,, Sbd where 1tsMt U.  - averaged over and those {U A, B, C-ciscreteness phase currents and stator voltage on rt -m interval; (ubOi | uC averaged over the inte, B, Csen discreteness of the phase currents and stator voltage on the (and-1) interval} itn - averaged over the inter iiA. B. C the discontinuity shaft is the phase flux linkages of the rotor at the ηth interval.  Since the control system was synthesized in a fixed coordinate system tied to the axes of the stator, the coefficients. j depend on the parameters of a particular electric motor 1 and on the averaged rotor speed on the (d) -1) discrete interval, the coefficients C 5 (u, C 6 L, j depend on the parameters of the electric motor 1, the average speed on (t} -l) -M interval of discreteness with tn-lj and from the control angles of converter 2, respectively, on the ft and (nl) Hvi intervals of discreteness. At the end of the (hl) -th interval of discreteness, the value of the averaged measured speed of cotii-Q is recorded in the discrete memory 15 where the values of the control angles of the transducer are already stored m 2 () th interval discreteness.  Therefore, in the beginning of the M-th discrete interval, the values of the mentioned quantities are fed to the inputs of the discrete block 14 of the calculated coefficients and the next one starts the calculation of the coefficients and quantities included in the expression for the average flux couplings,.  first of all, the determination of the coefficients C (l, g, C 4 & n i), which is carried out in tabular form. e.  their values are preliminarily calculated for a specific electric motor 1 for the entire range of speed variations and are recorded in a permanent memory device which contains a discrete block 14 of calculated coefficients.  After this & unit 14 calculates the averaged, phase stator voltages in the (p-1) discrete interval and the values of the coefficients C6 | u, |.  The averaged stator voltages are equal to the averaged phase voltages of the 2 frequency converter with direct coupling, and the latter, as is well known, are harmonic functions of the angles η up (converter U jy n - A with s (eijn t Ч1).  Coefficients Sat j 5 {U, | I calculate with elementary arithmetic expressions containing terms depending on the averaged speed GO Cn-il, and harmonic functions Shr, so9o, the phases of which depend on both the average speed and the angles of the converter control correspondingly to (tl-l) - M and m intervals of discreteness.  The values of the harmonic functions included in the expressions for the averaged phase voltages of the converter and for the coefficient C 6 | n; , as well as the terms depending only on the mechanical speed, are determined in the discrete block 14 of the calculated coefficients in a tabular manner, after which the sought values U m jc, C6 {u, j are calculated.  After calculating the control angles of the frequency converter 2 with a direct connection to the 1 st interval {which takes 10% of the duration of the discrete interval), their values come from the output of the block of 5 phase regulators to the inputs of the main memory unit IS, after writing to them to the inputs of the block 14 calculated coefficients.  The latter, after this, calculates the averaged phase voltages of the converter in the range UjuChJ and the values of the coefficients C5 / nj, as described above.  All calculated coefficients and values from the second flow of the block of 14 design coefficients.  arrive at the control input of the rotor flux linkage calculation unit 1O.In addition, the values of the averaged phase voltages of the converter in the vertical interval Ud, n1 from the first you. xc "a of the block 14 of the calculated coefficients arrive at the control input of 5 phase regulators.  Simultaneously, from the output of the discrete memory unit 15, the values of the average phase currents of the stator irtj n-llj are received at the inputs of the unit Yu of the computation of the flux-coupled rotor. “, N-OK3fu, j-U (,, - v, c. With 1 j i,) -. , 1, where j В, В, С.  At the end of the p-th interval, the block 15 of the operational memory: receives information about the average rotor speed of the CO and the phase currents of the stator from the outputs of the integrated analog-to-digital converters 19, 16-18.  After writing, the values of the latter go into the operational memory into one of the feedback channels of the block 5 phase regulators and to the inputs of the block 1О, so that the latter finishes the calculation of the averaged phase flux linkages of the rotor and determines the values of h, C in the syu.  Vc It should be noted that the computation of the averaged stator voltages indirectly and the parallelization of the computation processes, as described above, reduce the time taken in the (n + 1) -th discreteness interval to calculate the averaged phase rotor flux linkages. on the nth discrete interval, to a minimum, which reduces the delay of the control system of the device and improves the control dynamics.  The values of the calculated average phase flux linkages of the rotor.  McL l comes from the output of the rotor flux computation unit 1O to one of the feedback channels of the 5 phase regulator block.  Block coefficients 5 phase regulators R1 (u.  and P5 ju, j are functions of the parameters of the electric motor 1, the averaged rotor speed, and the angles of the inverter control in the n & n discrete interval.  Therefore, immediately after the end of the F-th interval, the recording of the value of the average velocity is hell.  In the discrete block 15 of the RAM, its value from the output of the receiver, together with the values of the control angles of res, is fed to the inputs of the discrete block 14 of the calculated coefficients, which is dried. The calculation of the mentioned coefficients.  The coefficients of a block of 5 phase regulators are calculated by elementary arithmetic expressions containing terms depending on the parameters of the electric motor 1 and the average rotor speed of the co, as well as the harmonic functions, 0055, which in turn depend on the pairs of meters of the electric motor one,. average rotor speed CjO || i3, and from the control angles of the frequency converter 2 with direct coupling on the And -th interval of discreteness.  As a component, depending only on the I parameters of the electric motor 1 and on the average speed and the necessary harmonic functions 31P§, C05O are calculated in block 14 in a tabular way, as mentioned above, after which the discrete block 14 of the calculated coefficients makes the final calculation of the coefficients Rlf, jfR5 | u, j, P (U, j fPSyu. j.  The values of the latter, as well as the control angles of the frequency converter {/ (yuW), are received from the first output of the block 14 of the calculated coefficients to the control input of the block 5 of the phase regulators.  After that, the latter calculates the control angles of the frequency converter 2 with a direct connection in the (M + 1) -th discrete interval over the following RV simulations. i4 | yt +. . i (. rOfuM, whereГ (, ф „l + 1 - sets the ai-ABC averaged interval of discreteness of stator phase currents and rotor flow couplings on the (n-2) -th interval;" iMi- (uW, | 4W averaged over the interval ML-V phase currents, stator voltages and rotor flux linkage at the P-th interval; lAit Oi iW - Uhl transform control. . . dc (frequency generator with direct connection, respectively, on (H – H1) -th and--th discrete intervals.  The values of the calculated control angles of the transducer 1.  in the (h + 1) -th discrete interval, in a digital code, go to the control inputs of the digital system 32 of the pulse-phase control (Fig.  3).  The latter is a three-channel digital code converter — a time interval synchronized with the mains supply, which converts the digital control codes of the CMS.  the pulses from its outputs to the control electrodes of the thyristors of the phase thyristor converters 33 35, as a result of which the stator of the asynchronous electric motor 1 receives the required voltages, at the beginning of the (tH-2) -ro interval of the discreteness, the block 5 of the phase regulators performs the calculation of the control angles of the frequency converter 2 by the expressions mentioned, only with other coefficients, p. ,one. ,; , ,P. 2 e. cju, a, 9. c PV, iH3 urn + P3p |. .  P, j-U (.  The values of the calculated control angles of the transducer on (I + 2) - vane shaft n, 1 + 2 in the digital code come from the output of the block of 5 phase regulators to the control inputs of the frequency converter 2 with direct connection, which then as described above.  As a result, at the (lH-l) and (n + 2) -th discrete intervals, the stator of the electric motor 1 is supplied with such voltages from the output of the frequency converter 2, which allow the (h + 2) -th discrete interval to work given averaged stator currents, the flow of the coupling of the gutter and the speed of the burner.  The operation of the electric drive at subsequent discretization intervals is carried out in a similar way. Thus, the electric motor is controlled in the electric drive 1 by discrete control of the frequency converter averaged over the interval of discreteness with a direct connection of the rotor speed and spatial vectors of the stator and the rotor flow.  Control is carried out in a fixed coordinate system, which eliminates the need for its orientation.  In the electric drive, when controlling the stator phase currents averaged over a discrete interval of the rotor speed, the phase currents of the rotor and the rotor coupling, the discrete properties of the controlled object are taken into account.  Control in a fixed coordinate system allows the abandonment of complex and unreliable coordinate transducers.  The implementation of a control system based on digital technology allows the computational operations of multiplying, dividing, calculating functions and. t, n  more simply and precisely, as a result of which all calculations, in particular, the indirect determination of the averaged phase rotor flux linkages and stator voltages, are carried out with a high degree of accuracy. In addition, it is possible to directly interface the electric drive control system with digital computing and various kinds of software -the setting blocks of other devices and systems.  Thus, the introduction into the electric drive of discrete blocks of calculated coefficients and RAM, as well as the execution of a unit for determining the alternating currents and rotational speed with integral analog-digital converters, provide increased control reliability and improved quality in dynamic operating modes.  °

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Claims (1)

AC ELECTRIC DRIVE OF A CIRCUIT OF A CIRCUIT OF CURRENT, containing an asynchronous motor with a squirrel-cage rotor, the stator windings of which are connected to the frequency converter with direct coupling, a speed control unit, the output of which is connected to the first input of the shaper for setting the stator phase currents and rotor flux linkage, the outputs of which are through the block of phase controllers connected to the control inputs of the frequency converter with direct connection, a phase current detection unit with phase current meters, connected to the subtraction unit coupling rotor flux linkage, the three-phase output of which is connected to the corresponding feedback inputs of the phase controller block, a synchronization unit, a rotation speed determination unit with a speed sensor, the output of which is connected to the second input of the stator phase current shaper and rotor flux linkage, which means that, with In order to improve the quality in dynamic operating modes,, 0n is equipped with a discrete block of calculated coefficients and a discrete RAM block, the inputs of which are connected to the outputs of the block phase regulators, phase current determination unit and rotation speed determination unit, the first and second three-phase outputs of the discrete random access memory block '' are connected respectively to the first and second three-phase inputs of the rotor flux linkage calculation unit, the third and fourth three-phase outputs and the fifth output of the discrete random access memory - with the corresponding inputs of the discrete block of calculated coefficients, the first and second outputs of which are connected to the corresponding inputs and control of the block of phase regulators i rotor flux linkage calculation unit, wherein the second three-phase output of the discrete random access memory block is connected to the corresponding feedback input of the phase regulator unit, and the phase regulator unit and rotor flux linkage calculation unit are ^{1 made} into vice multiply connected discrete converters, the phase current determination unit is equipped with phase integral analog -digital converters, the input of each of which is connected to the output of the corresponding phase current meter, and the output forms the corresponding phase the output of the phase current detection unit, the rotation speed determination unit is equipped with an integral analog-to-digital converter, the input of which is connected to the output of the speed sensor, and the output forms the output of the rotation speed determination unit, and the synchronization inputs SU., „1026272> tegral analog-to-digital conversions — currents and rotational speeds are connected to the output of phase detection units to the output of the synchronization unit.