RU2087068C1 - Electric drive - Google Patents

Abstract

FIELD: servo control systems. SUBSTANCE: introduced in electric drive are integrator 25, adding and subtracting units 21, 22. Reference-voltage generator is built up of chokes with primary windings inserted in circuits of field windings 6,7 of angle and speed sensor and secondary windings 18,19 connected through unlike-polarity rectifiers 16,17 to inputs of adder 20 whose output is connected to reference inputs of phase-sensing rectifiers 23. Inputs of the latter are connected through units 21 to output windings of angle and speed sensor which are connected through units 22 to speed transducers 24. Outputs of the latter and of phase-sensing rectifiers are connected to inputs of speed signal shaper. EFFECT: improved accuracy due to separation of speed and angle signals; simplified design. 4 dwg

Description

 The invention relates to electrical engineering and can be used in servo control systems.

 Known electric drive, made on a synchronous actuator with an angle sensor attached to them and a speed sensor, made, in particular, in the form of a synchronous tachogenerator (1).

 The disadvantage of the electric drive is complexity.

 Also known is an electric drive containing a motor connected to a frequency converter, an angle sensor connected at the input to the excitation generator, and at the output to the inputs of phase-sensitive rectifiers through high and low frequency filters. The outputs of phase-sensitive rectifiers and low-pass filters are connected to the inputs of the respective comparison units, at the outputs of which signals of rotor rotation speed are generated, the magnitude of which is proportional to the amplitude of the alternating current voltage on the excitation winding. These signals are applied to the corresponding inputs of the frequency converter (2).

 The main disadvantage of the electric drive is the low accuracy of the formation of angular and velocity signals, due to the fact that the excitation and output signals for angular and velocity coordinates are combined, and the separation of these signals is performed by electronic filters, which introduce distortions into the processing of static and dynamic parameters, which reduce the accuracy of measuring angular coordinates and rotation speed.

 The closest analogue to the invention is an electric drive containing a synchronous motor connected to the output of the frequency converter, an angle sensor, the field winding of which is connected to the output of the excitation generator, to which the input of the reference voltage generator is connected, the output connected to the reference inputs of phase-sensitive rectifiers. The outputs of the latter are connected to the inputs of the frequency converter through the multiplication units and to two inputs of the speed signal driver, in which the speed signal is generated by approximating the trigonometric functions of the rotor angular position (3).

 The disadvantage of this drive is the complexity and limited accuracy of the formation of the speed signal.

 The technical result of this invention is to simplify and improve accuracy by separating angular and high-speed signals, eliminating static and dynamic errors in the signal conversion paths.

 The specified technical result is achieved by the fact that in an electric drive containing a synchronous motor connected to a frequency converter, an angle sensor, the field winding of which is connected to the output of the excitation generator, a reference voltage generator connected to the output of the excitation generator, two phase-sensitive rectifiers, a high-speed signal shaper, two inputs connected to the outputs of the phase-sensitive rectifiers, the excitation generator, the reference voltage generator and the angle sensor are made of two phase, the secondary windings of the angle sensor are placed on mutually perpendicular teeth of the stator magnetic circuit of the synchronous motor, simultaneously forming the speed sensor windings, and the excitation windings of the formed angle and speed sensor are located in the holes made in these teeth, and the centers of which are located on the radial axis of symmetry of the teeth an integrator, two summing and two subtracting units, two speed converters, and the reference voltage generator is made in the form of two double-winding chokes, two ra of non-polar rectifiers and an adder, the output of which through the integrator is connected to the reference circuits of phase-sensitive rectifiers, and the inputs through bipolar rectifiers to the secondary windings of the corresponding inductors, the primary windings of which, forming the two-phase input of the voltage reference generator, are included in the circuit of the corresponding excitation windings of the two-phase angle and speed sensor, each output winding of which, through the corresponding summing and subtracting blocks, is connected to the inputs of the corresponding phase-sensitive a rectifier and a speed converter, the outputs of the speed converters are connected to two other inputs of the speed driver.

 In FIG. 1 shows a block diagram of an electric drive; in FIG. 2 - the implementation of the individual nodes of the electric drive; in FIG. 3 magnetic circuit of the stator of a synchronous motor with an angle and speed sensor; in FIG. 4 timing diagrams of the operation of electric drive units.

 The electric drive comprises a synchronous motor 1 with a two-phase angle and speed sensor. The rotor 2 of the engine is made in the form of a permanent magnet (conventionally shown bipolar). The first 4 and second 5 phases of the motor winding, the first 6 and second 7 phases of the field winding of the angle and speed sensor, and the first 8 and second 9 phases of the output winding of the angle and speed sensor are placed on the motor stator 3 of the motor (Fig. 1).

The motor is connected to a two-phase frequency converter 10, each phase of which is composed of a preliminary amplifier 11 and a power amplifier 12. The field windings of the aforementioned angle and speed sensor are connected to the outputs of the two-phase excitation generator 13 with an output frequency f ₀ to which the two-phase input of the reference voltage generator is connected.

 The reference voltage generator contains two double-winding reactors, which have primary windings 14, 15, forming a two-phase input of the reference voltage generator and are included in the circuit of the field windings 6, 7 of the angle and speed sensor, respectively, two different-polar rectifiers 16, 17, inputs connected to the secondary windings 18 , 19 chokes, respectively, and the adder 20, the inputs connected to the outputs of the rectifiers 16, 17, respectively.

 The electric drive is equipped with a summing 21 and subtracting 22 blocks. Each of the output windings 8, 9 of the angle and speed sensor is connected to the inputs of the corresponding phase-sensitive rectifier 23 and the introduced speed converter 24 through the corresponding summing 21 and subtracting 22 units. The reference circuits of the phase-sensitive rectifiers 23 are connected through the introduced integrator 25 to the output of the adder 20 of the reference voltage generator.

 The outputs of the phase-sensitive rectifiers 23 and speed converters 24 are connected to the corresponding inputs of the high-speed signal driver 26, the output of which is a signal in the form of a DC voltage, the value of which is proportional to the speed of rotation, and the sign (direction) is determined by the direction of rotation.

To organize feedbacks in angle and speed, the outputs of phase-sensitive rectifiers with voltages (U _1D , U _2D ) are connected to the corresponding inputs of the pre-amplifiers and a comparison unit 27 is introduced, the first input of which supplies a signal U ₃ , and the second input is connected to the output of the high-speed signal shaper 26.

 The high-speed signal generator may contain two multiplying devices 28 (Fig. 2) and a summing amplifier 29, the input of which is connected to the outputs of the multiplying devices 28.

 Keys 30 are introduced into the reference circuits of phase-sensitive rectifiers, the control inputs of which are connected to the output of the integrator 25.

The stator magnetic circuit of the synchronous motor contains teeth 31-42 (Fig. 3), on which the phases of the stator winding of the synchronous motor are located. On mutually perpendicular teeth 31, 37 and 34, 40 are placed windings 8 ^I , 8 ^{II of the} first phase and windings 9 ^I , 9 ^{II of the} second phase of the angle and speed sensor. Holes are made on these teeth, the center of which coincides with the radial axes of symmetry of the teeth, in which the first 6 and second 7 phases of the excitation winding of the angle and speed sensor are located.

поступающего на входы опорного напряжения фазочувствительных выпрямителей с выхода интегратора 25) преобразуется в сигнал U_1Д, U_2Д, представляющий в данном случае сигнал датчика углового положения ротора двигателя. Этот сигнал может быть подан на входы усилителей 11, которые вырабатывают синусоидальные (ПУ₁) и косинусоидальные (ПУ₂) функции (в виде напряжения или тока) для управления усилителями мощности 12 (УМ₁ и УМ₂). Напряжение U_1Д (U_2Д) подается также на формирователь скоростного сигнала 26 для преобразования выходных напряжений U_1Г, U_2Г преобразователей скорости 24 в сигнал постоянного тока. Выходные обмотки датчика угла и скорости, расположенные на взаимно перпендикулярных зубцах 31 и 37 по отношению к зубцам 34 и 40 (фиг. 3) и помеченные цифрами 8^I, 8^II и 9^I, 9^II, подключены к входам суммирующих 21 и вычитающих 22 блоков (фиг. 2). В общем случае суммирующий блок может быть выполнен на операционном усилителе, аналогично вычитающему блоку. В данной схеме он выполнен в виде перемычки, соединяющей полуобмотки 8^I и 8^II или 9^I и 9^II в последовательно согласно включенную цепь. Поскольку модулированный сигнал датчика положения на диаметрально расположенных полуобмотках 8^I и 8^II суммируется, а сигнал датчика скорости (ЭДС) вычитается, то на выходе суммирующего блока 21 образует сигнал, пропорциональный угловому положению α ротора 2, т.е.The electric drive operates as follows. When a reference signal U _{3 is} applied to the input of the electric drive, it enters the inputs of the preliminary amplifiers 11, which initiate power amplifiers 12, providing currents for rotation of the rotor of the synchronous motor. The latter starts to rotate and induces an emf of rotation U _Ω at the output windings 8 and 9 of the angle and speed sensor. This voltage is supplied through a subtracting unit 22 and a speed converter 24 to a speed signal shaper 26, where a signal is generated in the form of a DC voltage (U _tm ), the value of which is proportional to the speed, and the polarity is determined by the direction of rotation of the motor rotor. This signal (U _tm ) can be supplied to the second input of the comparison unit 27 as a main feedback signal in the electric drive. Simultaneously with the EMF of rotation at the output windings 8 and 9, a signal U _{α, which} is modulated by the speed of rotation, is carried, with a frequency carrier f = 2f ₀ . The windings 8 and 9 on the stator 3 of the motor are arranged so that a voltage is generated at their ends, from which the signal U _1α , U _2α is allocated when summing the voltages, and when subtracting the signal U _1Ω , U _2Ω The signal U _1α U _2α after detection in phase-sensitive rectifiers 23 (using reference voltage

the phase-sensitive rectifiers supplied to the inputs of the reference voltage from the output of the integrator 25) are converted into a signal U _1D , U _2D , which in this case is the signal of the sensor for the angular position of the motor rotor. This signal can be applied to the inputs of amplifiers 11, which produce sinusoidal (PN ₁ ) and cosine (PN ₂ ) functions (in the form of voltage or current) for controlling power amplifiers 12 (AM ₁ and AM ₂ ). The voltage U _1D (U _2D ) is also supplied to the shaper high-speed signal 26 to convert the output voltages U _1G , U _2G speed converters 24 into a DC signal. The output windings of the angle and speed sensor located on mutually perpendicular teeth 31 and 37 with respect to teeth 34 and 40 (Fig. 3) and marked with the numbers 8 ^I , 8 ^II and 9 ^I , 9 ^II are connected to the inputs of the summing 21 and subtracting 22 blocks (Fig. 2). In the General case, the summing unit can be performed on the operational amplifier, similarly to the subtracting unit. In this scheme, it is made in the form of a jumper connecting the semi-windings 8 ^I and 8 ^II or 9 ^I and 9 ^II in series according to the connected circuit. Since the modulated signal of the position sensor on the diametrically located half windings 8 ^I and 8 ^{II is} summed up, and the signal of the speed sensor (EMF) is subtracted, at the output of the summing unit 21 it forms a signal proportional to the angular position α of the rotor 2, i.e.

а на выходе вычитающего блока 22 сигнал, пропорциональный скорости вращения W ротора, т.е. (с учетом сдвига фаз на 90^o):

Напряжение с выхода блока 21 подается на вход фазочувствительного выпрямителя 23, где он детектируется и на его выходе образуется напряжение:

Поскольку при протекании тока i₀ (i₀₁ и i₀₂, фиг. 4) в обмотке 6 или 7 возбуждения датчика угла и скорости происходит модуляция потока в основании зубцов, на оси которых и размещены обмотки возбуждения, причем и в одном, и в другом полупериоде несущей частоты f₀ происходит уменьшение основного потока F₀₁ за счет насыщения этих участков магнитопровода, то наведенное на выходных обмотках 8 и 9 напряжение U₈₍₉₎ будет иметь удвоенную частоту f= 2f₀. Поэтому для детектирования в выпрямителе 23 необходимо иметь синфазное с выходным напряжением опорное напряжение

удвоенной частоты f=2f₀. Это напряжение в схеме электропривода формируется с помощью линейных дросселей Др. 1 и Др.2 (фиг. 1, 2), вторичные обмотки 18, 19 которых подключены к разнополярным выпрямителям 16, 17, выходные сигналы которых U₁₆, U₁₇ которых суммируются в сумматора 20. Формирование выходного сигнала U_f генератора опорного напряжения происходит следующим образом. Ток i₀, протекающий в первичной обмотке 14 (15) каждого из дросселей Др. 1 и Др. 2
i₀₁= i₀sinω₀t и i₀₂= i₀cosω₀t
наводит на обмотке 18 (19) соответствующего дросселя напряжение

где

коэффициент трансформации;
W_1,2 числа витков первичной и вторичной обмоток дросселя. После выпрямления напряжений U₀₁ и U₀₂ разнополярными выпрямителями 16 и 17 и суммирования их выходных напряжений сумматором 20 получается напряжение:

Поскольку напряжения U₀₁ и U₀₂ на обмотках 18, 19 являются производными от токов i₀₁ и i₀₂, протекающих в обмотках 14 и 15 соответствующих дросселей, то для получения синфазного напряжения

выходное напряжение U_f генератора подается на вход интегратора 25, на выходе которого и образуется напряжения

(U₂₅) опорной частоты f=2f₀, которое с помощью компаратора (фиг. 2) преобразуется в напряжение прямоугольной формы. На фиг. 4 показан процесс формирования опорного напряжения

где представлены: ток i₀₁ в обмотке возбуждения 6; магнитный поток Ф₀₁ в зубце 31 (фиг. 3); напряжение U₈ на выходной обмотке 8 (фиг. 1) датчика угла и скорости; напряжение на выходе выпрямителей 16 и 17 U₁₆ и U₁₇; напряжение на выходе сумматора 20 U₂₀ (оно же выходное напряжение U_f генератора опорного напряжения); напряжение на выходе интегратора 25 U₂₅

В случае необходимости для формирования сигнала главной обратной связи по скорости U_тм сигнал U_Ω с выходов вычитающих блоков 22 в общем случае через преобразователь скорости 24 (в качестве которого может быть использован операционный усилитель, в частности с RC-фильтром в цепи обратной связи для некоторой фильтрации входного напряжения) подается на вход Y соответствующего множительного устройства 28 (в формирователе скоростных сигналов 26, фиг. 2), на вход X которого подается сигнал U_α с выхода фазочувствительного выпрямителя 23. Напряжение с выхода множительных блоков (U_Ω•U_α) подаются на суммирующий усилитель 29, на выходе которого и образуется сигнал U_тм. Величина напряжения на выходе формирователя скоростных сигналов 26 с учетом ранее приведенных формул определяется следующей формулой:

т. е. напряжение U_тм прямо пропорционально скорости вращения и не имеет пульсаций. Полярность напряжения зависит от направления (знака) скорости, поскольку напряжение U_Ω изменяет полярность при реверсе направления вращения привода.

and at the output of the subtracting unit 22, a signal proportional to the rotational speed W of the rotor, i.e. (taking into account the phase shift of 90 ^o ):

The voltage from the output of block 21 is fed to the input of the phase-sensitive rectifier 23, where it is detected and voltage is generated at its output:

Since during the flow of current i ₀ (i ₀₁ and i ₀₂ , Fig. 4) in the field winding 6 or 7 of the angle and velocity sensor, the flow is modulated at the base of the teeth, on the axis of which the field windings are located, both in one and the other half the period of the carrier frequency f ₀ , the main flux F ₀₁ decreases due to saturation of these sections of the magnetic circuit, then the voltage U _{8 (9)} induced at the output windings 8 and 9 will have a double frequency f = 2f ₀ . Therefore, for detection in the rectifier 23, it is necessary to have a reference voltage in phase with the output voltage

doubled frequency f = 2f ₀ . This voltage in the electric drive circuit is formed using linear chokes Dr. 1 and 2 (Fig. 1, 2), the secondary windings 18, 19 of which are connected to bipolar rectifiers 16, 17, the output signals of which U ₁₆ , U _{17 of} which are added to the adder 20. The formation of the output signal U _{f of} the reference voltage generator occurs in the following way. The current i ₀ flowing in the primary winding 14 (15) of each of the chokes dr. 1 and dr. 2
i ₀₁ = i ₀ sinω ₀ t and i ₀₂ = i ₀ cosω ₀ t
induces voltage on the winding 18 (19) of the corresponding inductor

Where

transformation ratio;
W _{1.2 the} number of turns of the primary and secondary windings of the inductor. After rectifying the voltages U ₀₁ and U _{02 with} bipolar rectifiers 16 and 17 and summing their output voltages by adder 20, the voltage is obtained:

Since the voltages U ₀₁ and U ₀₂ on the windings 18, 19 are derived from the currents i ₀₁ and i ₀₂ flowing in the windings 14 and 15 of the corresponding inductors, to obtain common-mode voltage

the output voltage U _{f of the} generator is supplied to the input of the integrator 25, the output of which is formed voltage

(U ₂₅ ) of the reference frequency f = 2f ₀ , which, using the comparator (Fig. 2), is converted into a rectangular voltage. In FIG. 4 shows the process of forming the reference voltage

where are presented: current i ₀₁ in the field winding 6; magnetic flux F ₀₁ in the tooth 31 (Fig. 3); voltage U ₈ at the output winding 8 (Fig. 1) of the angle and speed sensor; the voltage at the output of the rectifiers 16 and 17 U ₁₆ and U ₁₇ ; the voltage at the output of the adder 20 U ₂₀ (it is the output voltage U _{f of} the reference voltage generator); voltage at the output of the integrator 25 U ₂₅

If necessary, to generate the main feedback signal with respect to the speed U _{tm, the} signal U _Ω from the outputs of the subtracting blocks 22 in the general case through the speed converter 24 (which can be used as an operational amplifier, in particular with an RC filter in the feedback circuit for some filtering the input voltage) is applied to input Y of the corresponding multiplier unit 28 (in high-speed signal shaper 26, FIG. 2), the input X U _α which is fed the output signal of the phase-sensitive rectifier 23. The voltage from a stroke multiplier units (U _Ω • U _α) are fed to a summing amplifier 29, the output of which forms the signal U _tm. The voltage at the output of the driver of high-speed signals 26, taking into account the previously given formulas, is determined by the following formula:

i.e., the voltage U _{tm is} directly proportional to the speed of rotation and has no ripples. The voltage polarity depends on the direction (sign) of speed, since the voltage U _Ω changes the polarity when reversing the direction of rotation of the drive.

 Thus, according to this invention, both the design of the electric drive due to the placement of the angle and speed sensor on the magnetic circuit of the engine and the conversion circuit of their signals are greatly simplified, which significantly increases reliability and durability.

 In addition, this makes it possible in principle to separate the signals of the combined angle and velocity sensor, i.e. to build paths of angular and high-speed signals autonomously without mutual influence on each other. This circumstance allows to improve the quality, namely, the accuracy of the electric drive in the development of a given rotation speed and angular position.

Claims (1)

 An electric drive containing a synchronous motor connected to a frequency converter, an angle sensor, the field winding of which is connected to the output of the excitation generator, a reference voltage generator connected to the output of the excitation generator, two phase-sensitive rectifiers, a high-speed signal shaper, two inputs connected to the outputs of the phase-sensitive rectifiers, characterized in that the excitation generator, the reference voltage generator and the angle sensor are made two-phase, the secondary sensor windings the angles are placed on mutually perpendicular teeth of the stator magnetic circuit of the synchronous motor, simultaneously forming the speed sensor windings, and the excitation windings of the formed angle and speed sensor are located in the holes made in these teeth, and the centers of which are located on the radial axes of symmetry of the teeth, an integrator is introduced, two summing and two subtracting blocks, two speed converters, and the reference voltage generator is made in the form of two double-winding chokes, two different-polar rectifiers and sums an ora whose output through the integrator is connected to the reference circuits of phase-sensitive rectifiers, and the inputs through bipolar rectifiers to the secondary windings of the corresponding inductors, the primary windings of which, forming the inputs of the reference voltage generator, are included in the circuit of the corresponding excitation windings of the angle and speed sensor, each output winding of which the corresponding summing and subtracting blocks are connected to the inputs of the corresponding phase-sensitive rectifier and speed converter, the outputs of the converter The speed sensors are connected to two other inputs of the speed driver.

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