SU546076A1 - The control method reversible two-phase asynchronous motor - Google Patents

Description

(54) METHOD FOR MANAGING A REVERSIBLE TWO-PHASE ASYNCHRONOUS MOTOR

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This invention relates to an auto-modulated width-modulated impulsive control and regulation technique with fixed full-widths to control the reversal of the falling edges during half-waves of a two-phase asynchronous motor, powered by a switchable thyristor voltage using known methods that use a refreshment motor.

The button for the joint inclusion of thyristors of both 1 shows the principal circuits of the bridge, the control of a two-phase asynch-ma system with the help of which a central motor is carried out during the operation of the described method; in fig. 2, 3, and 4 - vreu-converter or in the relay diagram of currents and voltages, by mode, resulting in the absence of 10n his essence.

smooth speed control Asynchronous two-phase motor 1 s 1 or in continuous amplification mode, control windings 2 and 3 and phase-shifted without the use of width modulated capacitor 4 connected to a source and with a fixed rear-feed position through a thyristor converter, front of control pulses 2. In the latter case, of the anti-parallel-switching case, the mechanical characteristics of the thyristors 5, 6, 7, 8. are intermittent and unstable. If there is an input signal at the moment

The aim of the invention is to obtain a time Ct) t cL includes a thyristor 5

stable mechanical and smooth regul- (fig. 3). Capacitor charge 4 occurs.

engine characteristics in different -20 flow through control windings 2 and 3

Claims (1)

modes of its operation and at any values of ij and ij, and due to the presence of the input signal. of the capacitor 4, the current -L carries a leading edge. This is achieved by the proposed rocter. As a result of the appearance of the rotating method, the turning on of thyristors of the obo-shaped magnetic field arises the electroma of their shoulders of the amplifier-converter, the output torque of the engine. The voltage of the capacitor through the open thyristor 5 is applied to the thyristor 7. Since in real two-phase motors the voltage on the capacitor in phase lags behind the supply voltage, then in this case the anode voltage of the thyristor 7 will lag behind in Un - therefore, the thyristor has the ability to turn on at the times corresponding to the negative half-wave of the supply voltage. FIG. 3 shows that after the time point of the op-amp t ° C the anode voltage of the thyristor Uy increases as the capacitor charges. while remaining phase shifted towards the delay with respect to the voltage Uf,. At the time of tot-оС) corresponding to the same input signal, the thyristor 7 is turned on. The voltage of the capacitor is applied to the thyristor 5, turning it off. The capacitor 4 is discharged through the winding 2 and the power source. After the capacitor is discharged, the voltage is directly applied to the thyristor 5 in the forward direction. Due to the wide control pulse, the thyristor 5 is turned on again. Starting from this moment, in the converter the joint conduction mode of thyristors 5 and 7 is set, which continues until the switching off of thyristors 5 and 7, when the currents through them –c i – g I 7 C decrease to n.sh. In the case of a negative half-wave, the UE includes thyristors 6 and 8, and the processes proceed in a similar way. With a change in the phase (polarity) of the input signal, the thyristors 6 and 8 have advance switching, the motor is reversed. In the thyristor co-conduction interval, the capacitor 4 is short-circuited, windings 2 and 3 are connected directly to the power source, and through them the current -12 5 phase pulses coincide under the effect of self-induced EMF. Thus, a braking torque occurs in this interval in the rotating motor. The magnitude of the resulting average motor torque is determined by the ratio of the durations of the conduction interval, when only one thyristor conducts, and the joint conduction interval, when the forward and reverse stroke thyristors simultaneously conduct the current. As the input signal increases, the duration of the joint conductance of the thyristors decreases, and the average torque of the motor increases. At the maximum input signal, the thyristors of the forward (reverse) stroke of the engine are turned on only, the average value of the electromagnetic torque of the engine takes the maximum value. As it is known, the occurrence of instantaneous braking torques in the intervals of joint production of thyristors DYNAMICS (which occurs twice in a period) causes the damping effect of a two-phase asynchronous motor with impulse control. As a result, the rigidity of the mechanical and smoothness of the control characteristics of the engine increases. Physically, this is due to the fact that with this method of pulse control, the interval duration corresponding to the motor mode does not increase with increasing rotational speed, but depends only on the input signal. As the rotational speed increases, the braking torque increases, thereby reducing the average torque and increasing the stiffness of the mechanical characteristics. For the same reason, idle speeds decrease as the input signal decreases. Therefore, the adjustment characteristics are stable and smooth. The use of this method of control in comparison with the known ones allows one to obtain higher-quality mechanical characteristics of the engine, which in terms of rigidity are not inferior to similar characteristics with amplitude control from a source of sinusoidal voltage. It should also be noted the high reliability of the circuit, since the converter is not threatened by the through short circuit. The motor is controlled steadily and smoothly in all engine operating modes and throughout the entire range of variation of the thyristor switching angles. Claims The method of controlling a reversible two-phase asynchronous motor powered from an alternating current thyristor converter by jointly turning on thyristors (opposite shoulders, characterized in that, in order to obtain stable motor control characteristics in all modes of operation, joint switching on the opposite shoulders of the opposite shoulders produces using modulated width control pulses having a fixed position of the falling edges for half a wave brotherly for the switched on thyristor of the supply voltage, Sources of information, received by her attention during the examination: 1. Pankratiev, L. D., et al. The trail at 5 AC waters with semiconductor amplifiers, Energia, 1S66, pp. 83-86 (prototype) .2, A. Wobraven. ControEf n | the speed of smdt6 induction motors by means of means of thynstors. PhiEips techtiicae review. VOE 28, 1, 1957. R ABOUT  cut 2J oi ,, gzg .Vc % ZG cC, Y5 ST II h Jd ir. S II 2/2 V “Pus.J (Jut -cut 2J Ojt 2ir cut 2 .f 29G ./ ig.ch cot