SU1561182A1 - Rectifier-inverter converter of ac electric rolling stock - Google Patents

Abstract

The invention relates to power converter technology and is intended to supply two identical DC loads. The purpose of the invention is to improve the weight and size parameters by reducing the installed capacity of the switching equipment. The converter contains two bridges on the main thyristors (the first bridge on thyristors 3-6, the second on thyristors 7-10), powered from a common AC network, and a forced switching node in the form of a single-phase bridge on switching thyristors 16-19 with switching capacitors 20 in the diagonal of the alternating current, with each DC output of the switching bridge connected to the same DC output of the corresponding bridge on the main thyristors. Such a connection allows one switching capacitor to forcibly lock the four main thyristors of the converter in pairs in each half-period. Moreover, at the beginning one pair of main thyristors, belonging to different main bridges and included in the switching circuits in series, is locked during the recharge of the switching capacitor from the original polarity of the voltage to the opposite, and in the next half-period the other thyristors are locked again to the original polarity of the voltage. 3 il.

Description

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315611

The invention relates to power converter technology and can be used in input converter devices with forced switching of thyristors intended for powering both collector, so and brushless collector motors of AC electric locomotives.

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The aim of the invention is to improve the mass and size parameters by reducing the installed power of the switching equipment.

Figure 1 shows the principle 15 electrical circuit of a reversible rectifier - inverter converter; Fig. 2 shows time diagrams of currents and voltages in converter elements, as well as time diagrams of thyristor states for a rectifying mode of operation; in FIG. 3 - the same for inverter operation mode of the converter.

The rectifier-inverter converter contains a traction transformer 1, the primary winding of which through the current collector 2 is connected to the traction contact network, two single-phase axles of the main thyristors 3-6 and 0 7-10, the terminals of a non-random current connected to the secondary winding 11 tons bend transformer 1, and direct current leads to loads 12 and 13, each of which is a circuit of a series-connected smoothing reactor 14 and a collector traction motor 15, a single-phase commutating thyristor bridge 16-19, the output of a positive Q pole connected to the output pole of the bridge of the main thyristors 3-6 and a negative pole output connected to the output pole of the bridge of the main thyristors 7-10, and the AC terminals connected to the terminals of the switching capacitor 20, and the control unit 21, corresponding pins connected to thyristor CQ control electrodes 3-10, 16-19. As the control unit 21, for example, a pulse-phase control system can be applied.

The converter in rectifying mode (Fig. 1 and 2) operates as follows.

Suppose, that the thyristors were originally carried out 3, 5 and 8, 10.

0

50

5 0, Q 45 CQ

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The in and i f3 currents of loads 12 and 13 are closed in the buffer circuits along the following circuits: 12; four; 6; 12 and 13; eight; ten; 13.

Let us also assume that initially, the switching capacitor 20 was charged before the voltage U2o, which is equal in magnitude to the amplitude value of the secondary voltage 11 (U, ff) of the transformer 1 o. U20 is shown in FIG.

At time 0, thyristors 4 and 9 o are turned on. Under the action of voltage U, | f, the polarity of which is shown in FIG, by an arrow, the currents ijH ijg are redistributed from the buffer circuit to the winding 11 and flow along the circuits: 12; four; eleven; five; 12 and 13; eight; eleven; 9; 13. At the same time, voltage UJf is applied to loads 12 and 13.

At time tf, the thyristors 16 and 19 are turned on. Under the action of the voltage yoke, the current ijf in the secondary winding begins to decrease, and in the capacitor 20 it increases along the circuit: + 20; sixteen; five; eleven; eight; 19 and -. The currents in thyristors 5 and 8 also subside. At time t, after locking the thyristors 5 and 8 and restoring their non-conductive properties, the current i1t decreases twice, becoming equal in magnitude to the currents of the loads 13 and closes along the circuit: 11; 9; 13; nineteen; 20; sixteen; 12; four; 11. Next in the time interval, the capacitor 20 is recharged by the load current. At time tj, when the voltage U10 begins to exceed the current value of the alternating voltage Utf, thyristors 6 and 7 open. In the time interval t3-t. currents of loads 12 and 13 are closed in buffer circuits along the following circuits: 12; four; 6; 12 and 13; 7; 9; 13, and the current of the winding 1 drops to zero under the action of the counter voltage of the capacitor 20 (the polarity of the voltage U2o is opposite to that shown in Fig. 1). In this case, electromagnetic energy stored in the inductances of the winding circuit 11 is current. , enters the capacitor 20, raising the voltage on it to a certain value. At time t, thyristors 16 and 19 are locked.

In the next half-period of the alternating voltage U (1, the charging of the capacitor 20 to the initial value of the voltage may be effected

the bridge from the actual supply winding 11 on the time interval ts - t. The same result can be obtained without the use of a special charging device, for example, by delaying the moment of switching on the main thyristors 6 and 7G, because before they turn on the load current ij2 ifj flows through the capacitor 20, linearly increasing the voltage on it (Fig. 2, dotted line U50 and 1 „).

By varying the time of switching on the thyristors 3, 4, 6, and 10 with respect to the zero phase voltage Up, independent (individual) voltage control on the loads is achieved.

Next, the processes proceed according to the timing diagrams shown in figure 2, similarly to that described.

Thus, when the converter is operating in the rectifying mode, the process of forcibly quenching the current in the transformer windings is carried out in two stages with the help of a switching capacitor. At the first stage, the two main thyristors are forcibly locked when the current in them is equal to half the total current of the transformer, and in the second stage, the second half of its current is artificially switched, which makes it possible to reduce the capacitance value compared to the prototype, eliminate the idle restart of the switching capacitor and its installed capacity.

The converter in dependent inversion mode (Figures 1 and 3) operates as follows.

Suppose that thyristors 3, 5, 7, 10 were initially conducted, and capacitor 20 was charged with voltage, the polarity of which is shown in Fig. 1. The currents of loads 12 and 13 were closed in the buffer circuits in the following circuits: 12; 3; five; 12 and 13; eight; ten; 13.

At time 0, thyristors 16 and 19 are turned on. Under the action of the voltage of the capacitor 20 (yoke), the current in thyristors 5 and 8 begins to decrease, simultaneously increasing in the winding And along the circuit: + 20; sixteen; five; AND; eight; 19, - 20. At the moment

t after locking and restoring the non-conductive properties of thyristors 5 and 8, the current in the winding 11 reaches a value of 0.510 1 c i fi and for

five

0

five

0

five

0

five

0

chained: + 20; sixteen; 12; 3; eleven; ten; 13; 19, - 20.

In the time interval t t - t (the capacitor 20 is recharged to the opposite polarity opposite to that shown in Fig. 1,

 moment t. - the moment when the voltage starts to exceed the current value of the alternating voltage Ufl - the thyristors 6 and 7 are turned on.

In the time interval tj -tg, the currents i (2 and i f e are redistributed from the circuit, thyristors 16 and 19, and capacitor 20 to thyristor circuit 6 and 7 and winding 11.

At the moment tg, the current of the winding 11 reaches the total current of both loads, the thyristors 16 and 19 are locked under the action of the counter voltage of the capacitor 20. The currents in and Ј0 are closed along the following circuits: 12; 3} 11; 6; 12 and 13; 7; AND; ten; 13. At the same time, a counter voltage U is applied to loads 12 and 13,

At time t 0, thyristors 4 and 9 are turned on. Under the action of voltage, thyristors 6 and 10 are closed, and currents n and -C e are closed in the following circuits: 12; four; 6; 12 and 13; 7; 9; 13.

By varying the time of switching on the thyristors 4 and 9, the voltage is controlled at the output terminals of the converter,

In the next half-period of the alternating voltage U (1, the processes proceed as described according to the time diagrams shown in FIG. 3).

Thus, when the converter operates in the inverter mode, the process of forced current buildup in the transformer windings is carried out in two stages with the help of a switching capacitor, and the forced locking of the two main thyristors is performed at the first stage when the current is equal to half the total current of the transformer. As a result, the installed capacity of the switching capacitor is reduced in comparison with the prototype by reducing the required capacitance value and eliminating idle overcharging.

Claims (1)

Invention Formula Rectifier-inverter converter of electric rolling stock AC, containing the bottom of a single-phase bridge, made on the main thyristors, the AC terminals of which are combined and form the input terminals, and the DC outputs are two pairs of output terminals, a forced switching node with a switching capacitor, in order to improve the mass -dimensional indicators by reducing installed The switching power of the switching equipment, the forced switching node is made in the form of four switching thyristors assembled according to the single-phase bridge circuit, each DC output of which is connected to the DC output of the corresponding bridge on the main thyristors, and the AC outputs are each connected to its switchboard condenser. but 04- 17.18 L Editor A.Lezhchina Compiled by V. Shitov Tehred L. Oliynyk Proofreader in.Cabations Order 983 Circulation 497 VNIIPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 113035, Moscow, Zh-35, Raushsk nab. 4/5 i g RigZ Subscription