SU1495943A1 - Method for control of thyratron motor - Google Patents

Abstract

The invention relates to electrical engineering. The aim of the invention is to increase the speed of a valve motor. This is achieved by shaping the current in the motor phases at equal angular intervals sinusoidally as a function of the rotor's angular position, setting the duration of the angular intervals, forming the current in each angular interval with a given amplitude and phase. The effective value of the current, the electromagnetic moment and, consequently, the speed of the valve motor increase. 5 il.

Description

The invention relates to electrical engineering and can be used in automatic control systems, in particular in low-speed servo systems with torque motors.

The purpose of the invention is to increase the speed of the electric motor by increasing the magnitude of the electromagnetic moment.

Figure 1 shows the oscillograms of currents in the phases of the main winding of a three-phase motor as a function of the angle of rotation of the rotor; figure 2 - the vector of the magnetizing forces of the root winding; FIGS. 3 and 4 show oscillograms of the current of one phase of a five-phase motor for the first and second versions of the law of current variation, respectively; figure 5 is a functional diagram of the drive.

implementing the proposed control method.

The electric drive (Fig. 5) contains a valve electric motor 1, on whose shaft a position sensor 2 is installed, in which the excitation windings are connected to the output of the modulator 3 to the input of which a control signal is fed and the secondary windings through phase-sensitive terminals 4-6 respectively connected with the first inputs of the switching blocks 7-9 and adders 10-12, as well as the inputs of the threshold elements 13-15. The latter are connected to the first, second, and third inputs of an OR 16 gate, whose output is connected to the control inputs of the switching blocks 7–9, the second inputs of which are connected to the outputs of the adders 10–12,.

WITH

ate with

and

00

The latter are connected by their second inputs to the outputs of inverting blocks 17-19 | INPUTs of which are connected respectively to the outputs of phase-sensitive rectifiers 5,6,4. The outputs of switching units 7–9 are connected to the inputs of current amplifiers 20–22 connected to the phases of motor 1.

The method is carried out as follows.

The currents in the phases of the motor 1 are formed by means of current amplifiers 20-22 connected by inputs to the outputs of the respective switching blocks 7-9, the law of the current change for each phase being determined by the output signal of the corresponding switching unit.

When the rotor rotates the motor 1, the voltage at the outputs of phase-sensitive rectifiers 4-6 varies sinusoidally, and these sinusoids are shifted in phase relative to each other by an angle (they correspond to sinusoids with a phase shift of 4- W / 3, 4-2 - 1G / 3 -ff, Fig. 1) These sinusoidal signals are initial for obtaining the required laws of current variation at each of the six angular intervals. The duration of the angular intervals is controlled by threshold elements 13-15 connected to the high voltage inputs of the logic element. IL 16. Each of the threshold elements pu1puls outputs 1 when passing through the zero sine wave output of the associated fazochuvst- pheno- rectifier.

So, at the end of each corner; the first interval f / 3 at the output of the logic element OR 16 a pulse arrives at the control inputs of the block; 7-9 switching. At the same time, the output of each of the blocks is switched to one of its three inputs, to which sinusoidal signals. The required amplitude and phase are applied. To obtain the required sinusoidal signals, the output signals of phase-sensitive rectifiers 4-6 are fed to the first inputs of switching blocks 7-9, to the first inputs of adders 10-12, and also to the inputs of inverting blocks 19-18, from the output of which inverted signals (FIG. , 1, sinusoids with (fj, tf -4 / G / Z and) are fed to the third inputs of switching units 9,7 and 8, respectively, to the second

0

five

the inputs of the adders 12, 10 and 11, where the addition of these signals with the output signals of the phase-sensitive rectifiers 6,4,5 and the resulting sinusoidal signals with H d -5 | G / 6, -f / G / 2 and ifg-ff The / d of FIG. 1) is served cor responsibly to the second inputs of the switching blocks 9,7 and 8.

When the switching inputs of the switching pulses 7-9 of the logic element OR 16 arrive at each of these blocks, the input bus of the associated current amplifier is connected to each of the three input buses of the switching unit. Moreover, at any time, the input buses of current amplifiers 20-22 are connected to various inputs of switching blocks 7-9. For example, if on the first angular interval (of 0- If / 3) the input of amplifier 10 is connected to the first input of block 7, then the input of amplifier 21 is connected to the second input of block 8, and the input of amplifier 22 to the third input of block 9, as a result The input of the amplifier 20 has a sinusoidal signal, with a phase shift C ((FIG. 1), the input of the amplifier 2 i is sinusoidal

0 signal with phase shift t, and at the input of amplifier 22 is a signal with cfg. At the end of the first interval o / f / 3, after passing a pulse from the output of the circuit OR 16, in the second interval amplifier 20 is connected to the second input of the unit .7, amplifier 21 - to the third input of the block 8, and the amplifier 22 - to the first input of the block 9, In this case, the law of change of the signal on the input of the amplifier 20 corresponds to the sinusoid from the input of the amplifier 21 - a sinusoid with (/ j., And at the input of the amplifier 22 - sinusoid with i /, Further, the switching occurs in a similar way,,

Thus, the input (master) signals of the current amplifier 20-22 are formed. According to these signals, in each angular interval of the current amplifier 20-22, a current is generated in the motor phases according to the law determined by the control method. This ensures a uniform rotation of the resultant vector of magnetizing force (n, s,) as a function of the angular position of the rotor, and the angle between the longitudinal axis of the rotor and the resulting vector ns is determined by the installation of a position sensor on the motor shaft.

five

0

five

five

The magnitude of the torque developed by the motors is controlled within the working area by the value of the control signal Uy, which is input to the module 3 controller. This signal sets the amplitude of the output sinusoids of phase-sensitive sensors 4-6, and consequently, the amplitudes of the sinusoidal signals used to form 10 required laws of change of phase currents and, accordingly, the value of the resulting vector of the NS, while, as the currents are formed in the motor phases according to the new laws corresponding to the proposed method of control laziness, for any values of the equalizing signal, the magnitude of the resulting vector is n. motor is higher than in known frequency control systems.

Consider the possibility of increasing the magnitude of the electromagnetic moment on the example of a three-phase motor with

OR;

go vector ns, UR; the magnitude of which is 1,732 magnitudes of the amplitude value, ns, each phase in the interval (- // / 3,0) it is necessary to change the phase points according to the law

i A cos

20

(d -t- Y / 6), (4) i A cos (e + G / 6), i -V3A sin (+ jr / 6),

where (, ic is the instantaneous value of the currents j A is the specified amplitude

value of currents

At the point o О, the vectors OA, OB and. OS have the same values

lOAl | OB1 (OS V3 / 2, (5),

and the vector OR coincides with the axis a. In the next interval (0, 3), the system of orthogonal coordinates is formed by the phases a and c, the resulting vector

windings a, b and c (fig, 2) with preserved-25, (geometric sum of vectors

In this case, the law of variation of the currents in a three-phase motor can only be possible, since for an odd number of phases, 1 1,2,3, .., сgа-1/2. Suppose that there is no current in phase C, and different phases are flowing in phases a and e, corresponding to specified amplitude values. Distribution on; The magnetising forces correspond to the OA and OB vectors. The resulting OR vector is equal to the geometric sum of the OA and OB vectors. If we take the absolute values of the vector-and OB, equal to 1, i.e., | OA1 10B | 1, then

1bk1 2 cos TG / b UZ 1,732 (1)

Consider the orthogonal coordinate system d, e and take as components of the vector OR the vectors OR and OS, which for the uniform displacement of the vector OR on the angular interval (- If / 3,0) should be changed according to the law

 OA and OC) serves as the first component of the vector OR, and phases L forming the second component (vector OV). In this case, the points change as follows

1d A cos (o - / 6) i. (6) C OUSE A sin (d (- / 6); ic -A cos (o / - / 6),

Similarly for the interval (f / 3,

40

2/3) have

igf t2 A cos 0; (7) i A sin of;

ic a sino. Further, on the next three intervals of the second half period, the laws of change of the phase currents (4), (6), (7) are repeated. Thus, to ensure a uniform displacement of the resultant vector OR with a frequency rotation of co (o tJ t, where t is time). it is necessary in the stator phases on the rear half-cycle of the rotation frequency to form currents on three angular intervals of duration G / 3 according to the laws (4), (6), (7). The form of currents in the phases of the motor | ORl - / 3 cos (o (+ 7Г / 6); fOCl V3 sin (o + f / 6)

; j

(2)

HO then

lorl

ic a sino. Further, on the next three intervals of the second half period, the laws of change of the phase currents (4), (6), (7) are repeated. Thus, to ensure a uniform displacement of the resultant vector OR with a frequency rotation of co (o tJ t, where t is time). it is necessary in the stator phases on the rear half-cycle of the rotation frequency to form currents on three angular intervals of duration G / 3 according to the laws (4), (6), (7). The shape of the currents in the phases of the motor / OAI 10В1 2cosW6, the bodies is shown in figure 1.

When powering three-phase momentarily, in order to provide the motor with a specified system of currents of uniform rotation, the resultant resulting vector is NS. uniformOR;

go vector ns, UR; the magnitude of which is 1,732 magnitude amplitude values, ns, each phase in the interval (- // / 3,0) it is necessary to change the phase points according to the law

i A cos

(d -t- Y / 6), (4) i A cos (e + G / 6), i -V3A sin (+ jr / 6),

where (, ic is the instantaneous value of the currents j A is the specified amplitude

value of currents

At the point o О, the vectors OA, OB and. OS have the same values

lOAl | OB1 (OS V3 / 2, (5),

and the vector OR coincides with the axis a. In the next interval (0, 3), the system of orthogonal coordinates is formed by the phases a and c, the resulting vector

, (geometric sum of vector

 OA and OS) serves as the first component of the vector OR, and phases L forming the second component (vector OB). In this case, the points are changed as follows

1d A cos (o - / 6) i. (6) C OUSE A sin (d (- / 6); ic -A cos (o / - / 6),

Similarly for the interval (f / 3,

2/3) have

igf t2 A cos 0; (7) i A sin of;

ic a sino. Further, on the next three intervals of the second half period, the laws of change of the phase currents (4), (6), (7) are repeated. Thus, to ensure a uniform displacement of the resultant vector OR with a frequency rotation of co (o tJ t, where t is time). it is necessary in the stator phases on the rear half-cycle of the rotation frequency to form currents on three angular intervals of duration G / 3 according to the laws (4), (6), (7). The shape of currents in the phases of the engine

bodies shown in figure 1.

HO rotates at a frequency corresponding to the rotor speed of the engine. With respect to the traditional system of sinusoidal currents, the magnitude of the resultant vector of the NS, is increased and amounts to 1.732 amplitude; phase winding, within the working area (the linear portion of the magnetization curve of the engine), respectively, increases the | s and the electromagnetic moment developed by the engine.

I Similarly to the above, it is possible to distinguish systems of orthogonal coordinates and determine the laws for the formation of phase currents for any number of phases m. In this case, the total number of phases 1 of the engine m is divided into two groups of phases, the geometric sums of the vector | s. which, at certain angular intervals, are made up by the number of the resulting vector of the NS, I, for example, can be distinguished for; variants in which are orthogonal: the system can be formed in groups of 1 and 14, 2 and 13, 3 and 12 and so more than | phases.

In general, to create a uniformly rotating field in a ha-phase motor, it is necessary to create a T-phase system of currents that are out of phase relative to each other by an angle of 2, set the duration of angular intervals, where 1 is the number of a variant of the law of current change, corresponding to the formation of an orthogonal coordinate system, which can take the values 4.6, .., for an even number of phases and, 2,3, ..., t-2/2 for an odd number of phases of the engine, in each phase in the first one. the angular interval of each period of the frequency of rotation to form a current at law Well, A, sir, (cf + c (), where A, A A is the specified amplitude value to - o1 - V / 2; upon termination of the first angular interval, on the next (n-1) angular intervals, form the current according to sin (d +), ((2j-1-P / 2),, 3,4, .., n (j is the number of the angular interval), Р 2га / 1 is the total number of intervals on the period, can take only integer values , moreover, n P + 1/2, if m is not a multiple of, and, if m is a multiple of 1, at the end of the n-th interval in the next (n + 1) angular interval

le form current according to the law i

(pi J

0

five

0

five

5 40 5 0

0

 A, G in (OH +0), where с of x X (3-2 / 2n-P + 1) at the end of the (n + 1) -th angular interval on the subsequent (pn-1) angular intervals to form a current according to the law 1 A sin (c / +

), where с („о ((k-n) -2 / 2n-P-H-. -Р / 2 + 13,, п + 3, п + 4, ..., Р.

I

For example, for two possible

the formation of an orthogonal coordinate system, 2. For the duration of the angular intervals is v ff / 5. Then - th / U. If, for example, then A ctg / 10 3.078A. In this case, the law of change of current in the first angular interval is i - 3.078 sin (o / - / 7/10). The total number of intervals on period m is a multiple of 1, therefore

p P / 2 5. Therefore, in the next four intervals, the current should vary according to the laws sin (o (), ij sinc (, sin (o (- / 5), i sin (f / 75) .Ha sixth angular interval current changes are similar to the law in the first interval, and in the next four intervals, the laws of current changes correspond to the laws in the intervals of 2,3,4,5, i.e. in this case, the laws of the currents change in the second half period. shown in Fig.Z.

For the second variant, they have V 2 G / 5, A, ctg F / 5 1,376A, since in this case m is not a multiple of 1, then n P + 1/2 3, in the first interval i 1,376 Sin (d-F / 5 ),

 2)

on the next two intervals i sin (o / - / G / 10), sin (el-W2), on the fourth interval 1,376 x X sin (d-2ll / 5y, Ha last interval (since p-n-1 1) i sin (with {-3 / 10). The current form for this case is shown in figure 4.

For the first variant (), the resultant vector is 3.078, and for the second () -2.618 the amplitude value of the phase n. Compared with the traditional system of harmonic currents (at which this value is 2.5), the magnitude of the resulting NS vector and, consequently, the electromagnetic torque of the motor increases, which leads to an increase in speed.

The laws of current formation and the increment of electc are determined similarly.

x

/ i

"W /

N

At "g

W

Fiyo.

Claims (1)

Claim A method of controlling a valve motor made in the form of an 'm-phase synchronous machine with galvanically unconnected phases and mechanically coupled to a rotational position sensor of a phase-rotary type, which consists in the function of the angular position of the rotor at each rotation frequency period in the sync phases - 30 chronic machines at equal angular intervals with a duration generate a current according to sinusoidal laws, control the duration of the angular interval and at the end of it change the parameters of the current generation law, and AZOV shifted from each currents relative to one another amounts to 217 / m, about tlichayuschiys I that, in order to increase the motor speed, · set duration angular intervals = 1? l / m, in each phase in the first angular range form said current legally i ⁽ '- A7sin (ci, at the end of the first angular interval at the following (p-1) angular intervals, the indicated current is generated according to the law i <P = A sin ("(+ c ( ⁽ g), at the end of the fifth angular interval by next (n + 1) angular interval formed by said current law i ^lhM J = a sin (a (+, at the end of the (n + 1) -th uglovog at the subsequent interval (p-n-1) intervals uglovyh- formed on said current law ^{(i lfc - A sin (d} + 0 (^ 9 wherein 1 - version number of current variation law (1 = 2,4,6 ,. ,. im-2/2 for an even number of phases and1 = 1,2,3,.,. 4 έ mn-1/2 for an odd number of phases), A, = A ctg 1Г1 / t, A is the specified value of the current amplitude, d is the angle of rotation of the motor rotor, ο ( ⁽ „= -7 / 2.0 (^ = 0 (^ x (2j - 1 - P / 2), j = 2,3,4, .. .ή (j 'is the number of the angular interval), P = 2m / 1 is the total number of intervals in the period, can only take integer values, moreover, η = P + 1/2, if m is not a multiple of 1, and η = P / 2, if m is a multiple of 1, = d ™ (3 - 2 / 2П-Р + 1), d = φ χ [2 (kn) -2 / 2n-P + lJ, k = η + 2, η + 3, η + 4, ..., Ρ. FIG. 2