SU1343519A1 - Arrangement for controlling thyristors in direct frequency multipliers with nonlinear load having hysteresis - Google Patents

Abstract

This invention relates to a converter technique and can be used in frequency multipliers. The purpose of the invention is to expand the scope. By introducing into the device a transistor, one-shot, a DC power supply, it is possible to use it in frequency multipliers operating on a non-linear load with hysteresis. 4 il. with 4 CO Sl

Description

The invention relates to converter technology and can be used in direct frequency multipliers when their load is electromagnetic elements with steel cores 5 for example electric motors.

The aim of the invention is to expand the field of application of the device by the possibility of its use in frequency multipliers operating on non-linear loads having a hysteresis.

FIG. 1 is a circuit diagram of a single thyristor mutual control unit of a frequency multiplier; in fig. 2 shows the output current and voltage plots of the converter whose thyristors are controlled by the device when setting up the delay unit by an angle D; in fig. 3 and 4 - similar diagrams when setting the delay unit for shutter speed -4L.

The device contains control 1 and control 2 thyristors of a ring multiplier circuit, RC-chain 3, shunt resistor 4, diode 5, first transistor 6, second transistor 7, intermediate pulse transformers 8 and 9, and pulse delay unit 10, for example, one-shot.

The control process takes place in the following way.

While the voltage U on the terminating thyristor 1 is applied in the forward direction, there is no current in circuit 3, since diode 5 interferes with this. After the thyristor 1 is naturally locked, o6paTHoe voltage appears on it and in the chain capacitor 3 there will be a current. If at this time the transistor of the switch 7 is already open, then the pulse of this current is amplified by the transistor 6 and through the transformer 9 is fed to the control electrode of the entering thyristor 2. If the transistor 7 is still closed, then due to an increase in the voltage U in the opposite direction the current in the chain 3 will increase, but only when the transistor 7 opens, the described process of opening the thyristic 2 will occur.

Key management 7 is performed in this order.

From the intermediate transformer 8, control motors are simultaneously supplied to the control electrode ty0.

before

Resistor 1 and the one-shot 10, KOTopFiifi, withstanding the time corresponding to L, opens klth 7, passes a current pulse through the transistor 6 and transformer 9 to the control electrode of the thyristor 2. At the same time, the one-vibrator of the driver of the next half-period is started through the transformer 9. Thus, the next thyristor in the cycle of operation cannot be opened earlier than through the angle L after opening the preceding thyristor, which ensures the stabilization of the operation of the converter.

However, if the initial opening of one of the thyristors occurred at the moment when the time angle 2Q was less than D before the natural thyristor closed. 2, i.e. Between adjacent pulses of the output current of a different sign, pauses will occur that are equal to OU, which will lead to a decrease in the output voltage and a lower input power factor of the converter.

To eliminate such a phenomenon, the one-shot is adjusted at a shutter speed of A-ii, 1, i.e. somewhat less than the half-period duration of the voltage required at the output of the converter. After switching on the converter to the network or when the load parameters change, a transient process will occur (Fig. 3 and 4). The initial pauses arising in this case gradually decrease to zero, and one of the half-periods (for example, positive, Fig. 4) becomes equal to A-j, the opposite increases to L + LA. After this, the process is stabilized. The output voltage, therefore, contains some constant component, the value of which depends on l. The smaller LL, the more symmetry between the magnitude and shape of the positive and negative half cycles of the output voltage and current, and the less constant they are.

The setting of the angle A depends on the stability of the holding of the single-vibrator used. It is impossible to allow LA to become negative, since in such a case during the transition process the pauses, on the contrary, will increase.

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and the output voltage decreases to. Too large l leads to a large constant component in the output voltage and current and to a distortion of their form. Practically A adjusts to an angle of the order of 1 °.

Resistor 4 is designed to protect the emitter-base transition of transistor 6.

Claims (1)

Invention Formula A device for controlling thyristors in direct frequency multipliers with a non-linear load, having a hysteresis, containing in each phase a first transistor, whose collector circuit is designed to communicate with a control electrode of a single-phase thyristor multiplier, and the emitter-base junction is intended for communication through a diode and an RC chain with an anode and a cathode of a thyristor of the previous phase, a communication transformer with primary and secondary windings, characterized in that, in order to expand the field of application by the possibility of its use Using frequency multipliers that operate on a nonlinear load, having a hysteresis, it is equipped with a second transistor rum, single-coupler, DC power source, and the communication transformer is equipped with a second secondary winding, with the primary winding of the transformer connected between the collector of the first transistor and one pole of the DC source between the emitter of the first transistor and the second pole DC source, the first secondary winding of the transformer is designed to be connected to the control electrode of a single phase thyristor, the second secondary winding is connected to the input of the downstream one-shot vibrator, the output of the one-shot vibrator of this phase is connected between the emitter and the base of the second transistor, its input to the second secondary winding of the transformer of the previous phase, and the pulse duration of the one-shot is determined by the expression . TLL Where 2K about; the duration of the mains voltage; frequency multiplication rate; angular frequency mains supply. uf Fird u) f Editor A. Shandor FIG. and Compiled by V. Bunakov Tehred L. Serdyukova Proofreader M.Sharoshi Order 4835/55 Circulation 659Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing enterprise, Uzhgorod, Projecto st., 4