SU1577059A1 - Method of controlling two-phase electric motor and device for effecting same - Google Patents

Abstract

The invention relates to automation and can be used to control a two-phase motor with a pole-pole rotor that performs the positioning of the working elements of any technological installation. The aim of the invention is to improve positioning accuracy. The method includes the formation of a voltage applied to the excitation winding U in and the control winding U y according to the laws U в = U о SINPϕ / 2 SIN ΩT, U у = U о COS Pϕ / 2 SIN ΩT, where ϕ is the specified angle of rotation of the rotor, P is the number of poles of the rotor, T is the time, ω is the angular frequency of the sinusoidal voltage of the network. The device contains a register. The information outputs of the register are connected to the information inputs "a" of the pulse-width modulator (PWM). The output of the generator 3 reference frequency is connected to the counting input "b" of PWM and to the counting input of the divider 4 frequencies. The output of the overflow counter divider is connected to the input "in" PWM. The PWM output is the output of the device and is connected to the motor winding and control windings. 2 sp.f-ly, 3 Il.

Description

yi vi

j

about yi &

p i to sin Ј sinwt, U

for U0COS 2U sinfc / t,

where ip is the specified angle of rotation of the rotor; p is the number of poles of the rotor; t is time; to is the angular frequency of the sinusoidal network voltage. The device contains a register. Information outputs of the register are connected to information

pulse-width modulator (SH) modulation inputs. The output of the generator 3 reference frequency is connected to the counting input S of the PWM and to the counting input of the divider 4 frequency. The output of the overflow counter divider is connected to the input B of the PWM. The PWM output is the output of the device and is connected to the motor winding and control windings. 2 sp.f-ly, 3 Il.

The invention relates to electrical engineering and can be used to control two-phase motors in automation systems for positioning the working bodies of process plants. The purpose of the invention is to improve the positioning accuracy,

Fig, 1 shows a diagram of a two-phase electric motor with a number of field sov p 2; in fig. 2 .- diagrams of the stresses on the control windings and

arousal; in fig. 3 is a block diagram of a device implementing a two-phase motor control method.

The motor contains a stator 1 and a rotor 2 with short-circuited windings. On the stator of the engine there are two windings; an excitation winding to which the voltage Ua is applied, and a control winding to which the voltage Uy is applied. The windings are shifted in space by 90 °, with / - the actual need to rotate the rotor.

The motor control method is as follows.

The stator windings are fed for example

UB U0-sin ™ sin cut; and „“ U0-cos --siniot;

The coupling coefficient of the excitation winding with the short-circuited rotor winding is proportional to cos 9 a

. Wi control sin - "

Rotor winding current:

1rot K (U0 sinEf cosЈf -55

p t. p o (- U0 cos Јr-sin-g) 1 costo t

 KU0.sin (- E | -) coswt,

$

-

five

five

0

five

where K - coefficient proportional to the net;

I mouth 0 at q о (i.e., the position of the rotor (oO is determined by the given value of if.

The magnitude of the torque that occurs when the rotor deviates from this position ((| - d - 0) is proportional to sin p (if-o (),

The stator windings of the motor can be applied to a rectangular shape shown in FIG. 2. The decomposition of these functions in the Fourier series indicates that the amplitude of the first harmonic in FIG. 2a is proportional to sin C, and in FIG. 26 cos If.

The formation of stresses of this form is performed by digital methods.

The device for implementing the method includes a register 3, the output of which is connected to the information input of a pulse-width modulator 4, the clock input of which is connected to the output of a master oscillator 5 of the clock frequency and to the input of a frequency divider 6, the output of which is connected to the recording input of a pulse-width modulator .4, the outputs of which are intended for connection to the terminals of the control windings and the excitation of a two-phase electric motor 7.

The device works as follows.

The reference frequency generator 5 produces voltage pulses that are applied to frequency divider 6. The frequency divider divides the frequency of the generator by N, thereby determining the frequency of the supply voltage of the motor windings.

The capacity of the register 3 and the PWM counters 4 is equal to N, the resolution of the rotation setting of the rotor is 2 / N.p revolutions.

Motor control is performed as follows.

A number is written to the register using a computer that determines the specified position of the rotor relative to the stator. The frequency divider generates a register overwrite signal to PWM counters. PWM generates the supply voltage of the excitation and control windings of the engine, the amplitudes of which are proportional to the corresponding RTC P f –since sin ™ - and cos

If the actual position of the rotor d does not correspond to the given if, then in the short-circuited windings of the rotor of the engine, a current is created leading to the appearance of a torque, the magnitude of which is proportional to sin p ((/ oo moves the rotor to a new position where the short-circuit current is - The rotor windings are zero.

Entering into the register a new number, differing from the previous one by a constant value, at equal intervals of time will cause the rotor to rotate at a constant speed equal to the given one. The discrepancy between the actual rotational speed and the specified rotational speed will result in a torque and accelerate or decelerate the rotational speed.

Thus, the two-phase electric motor control method and device for its realization allow positioning of the motor rotor relative to the stator with any given angle, as well as ensuring rotation of the motor rotor with a given rotation frequency.

Claims (2)

Formula invented and one . The control method is a two-phase electric motor with control and excitation windings on the stator and a pole-pole rotor with equal numbers. t. the control poles, the field winding and the rotor, at which the feed to the winding is changed to excitation and control voltage winding, characterized in that, in order to improve positioning accuracy, the voltage variation on the excitation winding are legally from uo sinwt sin (p (), and on the control winding - according to the law Uy U0 sinwt -cos (pc // 2), where U0 is the amplitude of the sinusoidal voltage; Lf is the specified angle of rotation of the rotor with respect to the stator; P is the number of poles; t is time; W angular frequency of the sinusoidal voltage network. 2. A device for controlling a two-phase electric motor, comprising a master clock oscillator, an output connected to the input of a frequency divider, characterized by by the fact that, in order to improve positioning accuracy, a register, a pulse-width modulator with information, clock inputs and a recording input and four outputs, are entered into it, the register input is intended to supply a reference signal, the register output is connected to the information input of a pulse-width modulator, the counting input and the recording input of which are connected respectively, with the outputs of the master clock frequency generator and the output of the frequency divider, the outputs of the pulse-width modulator are designed to be connected to the terminals of the windings control and excitation of a two-phase electric motor. P ".L Editor S.Pekar Compiled by S.Pozdnukhov Techr ed M.Didyk Order 1855 Circulation 457 VODIL of the State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 4/5, Moscow, Zh-35, Raushsk nab. 113035 I, I I I,,, I III I II II II I -LI .Tf III G1 I. . . -I GL .I IT - - G, Production and Publishing Combine Patent, Uzhgorod, st. Gagarin, 101 FIG. g Proofreader N. Revska Subscription