SU1443107A1 - Rectifying-inverting converter - Google Patents

Abstract

The invention relates to electrical engineering and can be used on railway rolling stock as a main reversing converter. The purpose of the invention is to reduce mass and size parameters, increase efficiency and expand the working range. The device consists of a rectifying bridge on thyristors 1-4, the input diagonal of which includes a sectioned secondary winding 6 of a transformer, each section of which is shunted by one of the capacitors 7, 8. Additional thyristors 9-12 are connected in pairs in series and between their common connection points is switched the capacitor 13. The anodes of the thyristors 9, 10 are connected to the anodes of the thyristors 1, 2. The cathodes of the thyristors 11, 12 are connected to the cathodes of the thyristors 3, 4. Due to the provided 11 controlled recharging of the capacitor 13 current m is reduced load capacitance of capacitor 13, and the passage of this current is not related to the duration of commutation. The reactive energy of the AC circuit is dissipated during commutations in the input circuit, the switching of the thyristor arms takes place almost instantaneously, and the capacitor 13 serves only to provide circuit locking of the thyristors, the duration of which is shorter than the switching time. 3 il. (L

Description

The invention relates to electrical engineering and is intended for use as a main AC-DC converter in a constant (traction mode) and vice versa (in a regenerative braking mode), for example, on railway rolling stock.

The purpose of the invention is to reduce the mass indicators, increase the gearbox efficiency and expand the working range of the converter.

Figure 1 shows a circuit diagram of the transducer; FIG. 2 shows the timing diagrams of the operation of the converter for the algorithm of operation with forced locking of all thyristors; FIG. 3 shows time diagrams I: 1 using thyristor switching using voltages of sections of the secondary winding of the transformer.

The rectifier-invertor converter (Fig. 1) contains a rectifying thyristor bridge, consisting of thyristors 1-4, through which the load 5 (electrical machine) is connected to the secondary partitioned winding 6. In parallel with each section, capacitors 7 and 8 are turned on. Anodes The first 9 and third 10 additional thyristors are connected to the anodes of thyristors 1 and 2 of the light bridge, and the cathodes of the second 11 and fourth 12 additional thyristors - to the cathodes of thyristors 3 and 4 of the same bridge. The cathode of the first 9 and ano second I} additional thyristors

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five

The total thyristors 9-12, with ,, j - denote the time intervals j and the numbers correspond to the designation of the thyristors in fig.I.

The time interval t corresponds to the beginning of the buffer period in which the load current closes outside the transformer windings 6 through thyristors 10 and P. A load current recharges the switching capacitor 13, after completion of which includes the thyristor 12. The thyristor 1 is locked by the voltage U of the capacitor 13 and the load current in the time interval t 7 passes through the buffer {at the circuit from thyristors 10 and 12. Before switching on the load current into the winding 6 of the transformer (in the interval t), the thyristor 9 is unlocked. By voltage U, the thyristor 10 is locked and ap d capacitor 13, after which the thyristor 2. The thyristor 9 is locked and the voltage + 2. The load current is abruptly connected to one section of the secondary winding 6 of the transformer through thyristors 2 and 12. In the primary winding of the same transformer, the current

at stake due to the excitation of the oscillatory process in the input circuit. In the time interval tg, the thyristor 11 is unlocked, and the thyristor 12 is locked by the voltage Ui of capacitor 13 and the last is recharged. At the time of completion of the first half period, the current in the input circuit is unlocked by the thyristor 3. The thyristor 11 is locked by: U y + U / 2. Cole

a commutation process in the input circuit is connected to one of the outputs

The capacitor 13 is connected to the middle point of the secondary winding 6 of the power transformer, as well as the cathode of the third 10 and the anode of the fourth 12 additional times of the resistors.

stops, the load current is introduced into the entire secondary winding 6 of the transformer and the rectifying period t begins.

The switching process (time intervals on the diagrams (Fig. 2) of the junction tj, to tr) is accompanied by the imposition of a denotation: the U curves, they are, respectively, the voltage on the secondary winding of the transformer 6 and the current in its primary winding, i.e. . consumed from the pitak network; curve Uj is the voltage across the switching capacitor 13 (the polarity of the voltage U and u is shown conventionally and corresponds to its designation in figure 1). The remaining diagrams illustrate the open and closed intervals of thyristors 1-4 of the rectifying bridge and stop, the load current is introduced into the entire secondary winding 6 of the transformer and the rectifying period t begins.

Switching process (time intervals

the half-period of the voltage of the natural oscillations of the input circuit on the curve of the stand-point voltage U-j.

The change in the beginning of the interval t 4 (phases) is controlled by the average value of the rectified voltage at load 5. The rectification period t ends with unlocking of the thyristor 9. The thyristor 2 is locked with the voltage Ui-Ui / 2. In the time intervals t., Tg arises in the same way as described, the oscillation process during

the input circuit and the current i are cosineally reduced to a relatively small forced current of the specified circuit by the end of the interval tj, which begins when the thyristor 10 is unlocked and the thyristor 9 is locked by the voltage U., the capacitor 13. The load current from the latter is output and Thus, the voltage and is limited regardless of the duration of the switching (for example, removing the load current from the windings 6 of the transformer). At the end of com10

interval t) voltage 1) is sufficient to ensure reliable switching of the thyristor arms.

In the interval t (Fig. 3), the thyristors 9 and 12 are turned on, the thyristor 1 is locked by the voltage U of the capacitor 13 and recharged the latter to the specified value, then the thyristor 1I is turned on and the load current passes through the circuit of thyristors 9 and 10 is the buffer interval t .. This interval ends when unlocking the thyristor 2 and locking the thyristor 9 mutation unlocks the thyristor I, and ty- 15 with the voltage U .. Similarly, the opistor 3 is locked by the voltage to the sled algorithm (FIG. 2) b-trans winding (section) -U-I / 2. The oscillatory process in the input circuit is terminated, the load current is output from the winding sections 6 of the transformer to a circuit of a series-connected thyristor 10, a capacitor 13 and a thyristor 11.

Then, the converter's operating process control similar to that described in the following, conditionally negative half-period of the supply voltage, occurs, except that instead of thyristors 2 and 3, thyristors 1 and 4 are included respectively (Fig. 2). To more evenly distribute the load current across the converter's shoulders in the buffer period, one can alternate half-periods of the supply voltage of the thyristors 10, 12 and 9, II, for which at the beginning of the interval t. thyristor 9 is unlocked (instead of 12 in the preceding half period), and at the end of this interval, thyristor 12 is unlocked (instead of thyristor 8).

In order to reduce the operating frequency of the switching capacitor 13 and reduce the number of its recharges in the buffer interval to one, another converter control algorithm (FIG. 3) can be applied, where the curve and is the voltage in the supply mains characteristic of high-power consumers and the secondary voltage of the transformer, which contains distortions transformed from the mains supply, as well as arising in the input circuit during switching. At the same time, time L is insufficient for restoring the locking properties of the corresponding thyristors without using forced locking. At the time of the end of switching (end

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of the formatter in the time interval t through the thyristors 2 and 11 and the capacitor 13, and in the interval t through the thyristors 2 and 12. At the time of the completion of the switching, the thyristor 3 is unlocked. which is the same as the process of removing the current from the load from the winding 6 of the transformer at intervals t, t-, is similar to

this algorithm, except that in the buffer interval

There is one recharge of the capacitor (Fig. 3).

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Claims (1)

Invention Formula A rectifier-inverter converter, containing a power transformer, the secondary winding of which is made up of two sections connected in series, each of which is bridged by a capacitor, and connected to the terminals for connecting the load via a rectifying thyristor bridge, the anode group of shoulders 45 of which is connected to the anode the first additional thyristor, and the cathode - with the cathode of the second additional thyristor, the anode of which and the cathode of the first additional thyristor are connected to one of the terminals of the switch a capacitor connected by a second output to the connection point of the secondary sections of the power transformer, characterized in that it is equipped with the third and fourth additional thyristors in order to reduce the overall dimensions, increase efficiency and extend the operating range, interval t) voltage 1) is sufficient to ensure reliable switching of the thyristor arms. In the interval t (Fig. 3), the thyristors 9 and 12 are turned on, the thyristor 1 is locked by the voltage U of the capacitor 13 and recharged the latter to the specified value, then the thyristor 1I is turned on and the load current passes through the circuit of thyristors 9 and 10 is the buffer interval t .. This in of the formatter in the time interval t through the thyristors 2 and 11 and the capacitor 13, and in the interval t through the thyristors 2 and 12. At the time of the completion of the switching, the thyristor 3 is unlocked. At the same time, the thyristor 12 is locked by the voltage of one section of the winding 6 and which is the same as the process of removing the current on the load from the winding 6 of the transformer in the intervals t, t-, is similar to this algorithm, except that in the buffer interval There is one recharge of the capacitor (Fig. 3). 12 Invention Formula The rectifier-inverter converter, containing a power transformer, the secondary winding of which is made up of two sections connected in series, each of which is bridged by a capacitor, and connected to the terminals for connecting the load through a straightening thyristor bridge, the anode group of the arms of which is connected to the anode of the first additional thyristor, and the cathode - with the cathode of the second additional thyristor, the anode of which and the cathode of the first additional thyristor are connected to one of the commutator outputs guide capacitor, a second terminal connected to the junction sections of the power transformer secondary winding, otlichayuschiy- in that in order to reduce the large-sogabaritnyh indicators, increasing the efficiency and expansion of the operating range, it is provided with third and fourth additional thyristor, a coedinesh s in series, the connection point of which is connected to the connection point of the secondary sections of the power transformer, the anode of the third / / 9 W 11 1Z additional thyristor connected to the anode of the first additional thyristor, and the fourth cathode - with the cathode of the second additional thyristor. .Z U1  Rig. J