SU1432684A1 - Arrangement for switching rectifiers of transformer-gate converter - Google Patents

Abstract

The invention relates to converter technology and can be used for switching control windings of transformer-key frequency converters, as well as in semiconductor breakers, alternating current switches. The purpose of the invention is to expand the scope. The switching device can operate in switched AC circuits without an additional source of charge for the switching capacitor. The device contains a switching thyristor 2, a charging autotransformer 5, a switching capacitor,., Torus 10, as well as a backup switching capacitor S and 12, and a thyristor 3, ko (L

Description

with

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05 CX) 4

l /

The latter are involved in closing the power thyristor I only at those times when the main switching capacitor 10 has insufficient voltage for switching. The voltage level at the main switching capacitor 10, at which the backup condensate comes into operation

32684

The torus 12 is controlled by an optoelectronic threshold element 16, at the output of which a logical signal is generated. The formation of the control pulse of the backup switching thyristor 3 is carried out in digital form in conjunction with the converter control unit 20. 2 Il.

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The invention relates to devices and converters and can be used for switching; control windings of transformer-key frequency converters. : a significant output of I currents (on the order of one thousand amperes or more), as well as in semiconductor interruptions of Hotels, alternating current switches,

The purpose of the invention is to expand the scope of application.

Fig. 1 shows a functional diagram of the device for switching in Fig. 2, time diagrams of voltages illustrating the operation of the device. properties ..

The device for switching the power thyristor 1 contains switching 2 and additional 3 thyristors connected by cathodes at points 4 to which the charging autotransformer 5 is connected, the winding of which consists of two parts 6 and 7 The beginning of the winding of the autotransformer 5 is connected to the anode of valve 8 The cathode of which is connected to the point 9 of the connection of one plate of the switching capacitor 10, the anode of the switching thyristor 2 and the anode of the additional valve II. The additional switching capacitor 12 is connected to one point of the cathode of the additional valve 11 and the anode of the additional switching thyristor 3, and the other to the point 13 of the connection of the anode of the power thyristor 1, another plate of the switching capacitor 10 and the positive terminal of a single-phase diode bridge 14 "End the winding of the autotransformer 5 is connected to the negative terminal of the bridge 14, which by alternating current forms the leads 15 for connecting a switched circuit

(for example, the control winding of the transformer-key converter) Parallel to the switching capacitor 10 is connected the input of the threshold element 16, and its output through the inverter 7 is connected to one of the inputs of the element 18, whose output is connected to the control through the driver 19 an additional thyristor electrode 3. The second input of the element 18 and the control electrode of the power thyristor 1 are connected to the output of wide pulses of the control unit 20 The threshold element 16 can be built, for example, on a transistor Ron, the input of which is provided with a controllable high impedance divider with the appropriate restriction chains setpoint threshold, and its output is connected to a circuit generating a logic signal. The former 19 is built, for example, on the basis of a waiting mute, which reacts to a falloff of a pulse arriving at its input and then amplifying the output signal for supplying a thyristor to the control electrode.

The device works as follows.

To ensure the operation of the transformer-key frequency converter, it is necessary to alternately short-circuit and open two control windings located on the extreme rods of the three-core magnetic circuit when powered from the primary sinusoidal voltage network. Such switching is provided by connecting the leads 15 of the diode bridge 14 to the control winding. When power thyristor 1 is first turned on, capacitors 10 and 12 are charged with polarity, indicated by

1432684

1, without brackets (positives at the time, and retains its own values in Fig. 2), the voltage due to fixing it with a wire, induced on the part 6 with type 11 until time t or winding at the time t4j tg, 5, due to the flow of the operating current. At the same time, t, t occurs on part 7 of this transformer, reliable closing of the thyristor 1, so that the power thyristor 1 turns on as a voltage across the capacitor 10 impulses, and more than the threshold level. When turned off - by pulses U, which are Q (when thyristor l is turned on) the commons are generated by the control unit 20, the capacitor 10 may not work out. The duration of the pulses corresponds to receive enough energy for the duration of the switched on-next switching, so as an instantaneous thyristor I, ensuring sufficient value of the voltage Ujj. the exact value of the switching voltage is i5 to zero, and the recharge energy along the way: the capacitor 10 for the primary thyristor 1, the winding part 6, the closing valve of the power thyristor 1 may8 be insufficient. Tg to be made by selecting the appropriate value in the interval ±, 4 tg at the output of the starting moment of the converter 18 passes a pulse, and at (for example, the time t 0 to 20 the control electrode of the additional figure 2) using the control unit , the thyristor 3 from the output of the imaging unit 19, as well as the choice of the ratio of the number. At the moment txi, a pulse U enters, coils of the winding parts 6 and 7, C, when the thyristor 3 is turned on, a sufficient mutating force is applied to the force pulse of the control pulse 1. thyristor 2 at the time of time 25 reverse s condenser 12 nor t. reliable closing occurs and reliable switching occurs, the thyristor 1 being injected. The capacitor 10, the over-capacitors 10 and 12 are recharged to charge with the polarity indicated by the polarity shown in the brackets in brackets in FIG. 1 ( This voltage of the value U,) along the circuit: part of the winding 7.30 in the interval of bridge 14, thyristor 2 to the voltage. The next time the thyristor is turned on, determined by the instantaneous value of 1 at the time t, the capacitors 10 and 12 of the voltage and, at the time tV, are reloaded with polarity without speed. Since, in the interval O-tj, the voltage and time are repeated on the capacitor 10 is greater than the threshold, ,, 5zhe sequence. In order to facilitate the U value, which determines the on-mode of operation of the power thyristor 1, reliable switching (Fig. 2), then when you lock it by reducing the speed of the element 18, the signal does not decrease to zero direct current (Fig. 2). , U; | g) i.e. the output of the threshold and amplitude of the reverse current between the common element 16 passes pulses, with the connection point of the cathodes commutative corresponding to a positive value of 2 and an additional 3 Tiris, which are above the threshold limit and common point of the cathode . At the same time, the additional end of the power thyristor I and the middle capacitor 12 maintains the voltage for switching the charging autotransformer by switching before the next switching on 5 the choke of the power thyristor 1 can be switched on at time t. At this point in time, the continuous voltage monitoring capacitor 10 recharges — on the switching capacitor (with the polarity indicated without the speed required for the commutation, to the voltage dependent on gQ). ) and the use of the standby mode of the operating current value and on the value of the additional switching capacitance of the opposite polarizer allows this TI to be used, to which the condens device is recharged when powered from the source ennogo voltage. Supplementing the switching thyristor 2, the auxiliary gg capacitor charges and maintains the downward capacitor 12 at the time required for locking the power menus t is charged, because the voltage of the thyristor up to that moment is the instantaneous value of time, when switching voltage U; is greater than this, the voltage across the main switching air conditioner will be lower than the minimum level required for switching.

The use of a device for switching control windings in converters operating on the principle of switching the magnetic flux in a three-core magnetic circuit and used in special metallurgy (electromagnetic metal stirring units in vacuum furnaces will improve the quality of the alloy and reduce waste.

Claims (1)

Invention Formula A device for switching transformer key converter valves, the control electrodes of which are intended to be connected to the wide pulse outputs of the control unit, containing a switching thyristor, the control electrode of which is intended to be connected to the output of narrow pulses corresponding to the wide pulse ends, the control unit, the cathode - for connection to the cathode, and the anode is connected to the first plate of the switching capacitor and the cathode of the diode whose anode is connected to the beginning of the charging autotransformer coils, the tap of which is intended to be connected to the cathode of the valve, to be connected to the anode of which started second lining commute -iQ 15 20 25 4326846 a capacitor, characterized in that, in order to expand the field of application, an additional diode and a capacitor, an additional thyristor, a series-connected threshold element, an inverter, the first input of the AND element and a short pulse shaper, a single-phase diode bridge are inserted, the anode of the additional thyristor is connected to the connection point of the first additional capacitor and the cathode of the additional diode, the anode of which is connected to the first plate of the switching capacitor, is turned off The additional capacitor is connected to the second plate of the switching capacitor, the cathode of the additional thyristor is connected to the cathode of the switching thyristor, the first and second plates of the switching capacitor are connected to the first and second inputs of the threshold element, the second input of the And element is connected to the output of the wide pulses of the control unit that controls elec. An additional thyristor is connected to the output of a short pulse shaper, the end of the autotransformer winding and the second plate of the switching capacitor are connected respectively to the negative and positive terminals of a single-phase diode bridge, the AC terminals of which are the code of the device. thirty 35  : h VNIIPI Order 5А57 / 50 Circulation 666 Chronically-polngr. pr-tie, Uzhgorod, st. Project, 4 4J Subscription