SU1081628A1 - Device for adjusting a.c.voltage - Google Patents

Abstract

A device for regulating alternating voltage, containing a transformer, the primary primary winding of which is included in the diagonal of the first bridge on controlled bidirectional valves, which are open at the other terminals of the diagonal and connected to the main capacitors connected to the input diameters, and the drawers have the same diaphragms. adjusting and improving the output voltage curve, it is equipped with a second bridge on unidirectional controllable gates and two auxiliary condoms Satoru, and a transformer - additional winding connected to the input terminals through a second bridge between the outputs of one diagonal and whose common point connecting one of the terminals additional (A winding and the respective input terminal included auxiliary capacitors.

Description

oh

3d

ND

X 11 The invention relates to electrical engineering, in particular, converter technology, and can be used in power supplies. A device for regulating alternating voltage is known, which contains a transformer with main and additional windings, one of which is connected directly and the other through controllable gates lj. The disadvantage of this device is the distortion of the shape of the output voltage curve at large opening angles of controlled valves. It is also known a device for regulating an alternating voltage containing two transformers, the primary and secondary windings of which are connected in series, and the common connection point of the primary windings through the corresponding thyristors the keys are connected to each input terminal of the pj device. The disadvantages of this device are the large size and distortion of the shape of the output voltage curve at large opening angles of the thyristor keys. The closest in technical essence to the proposed is a device for regulating an alternating voltage containing a transformer, the primary main winding of which is included in the diagonal of the first bridge on controlled bidirectional fans, the open ends of which are another diagonal through corresponding thyristors and main The capacitors are connected to the input pins H. However, the known device has an insufficient output voltage control range. The aim of the invention is to expand the control range and improve the shape of the output voltage curve. The goal is achieved. The device for regulating the alternating voltage contains a transformer, the primary basis1 and the winding of which is included in the diagonal of the first bridge on controlled bidirectional valves, the open ends of the other diagonal of which are connected via 8 to the main thyristors and main capacitors input pins, additionally equipped with a second bridge on unidirectional controlled valves and two auxiliary capacitors, and the transformer - an additional winding, connecting Auxiliary capacitors are connected to the outputs of one of the diagonals and the common connection point of one of the additional winding leads and the corresponding input output. FIG. 1 shows an electrical circuit of the device for adjusting the alternating voltage f in FIG. 2, time diagrams of the supply voltage and currents of the primary primary and secondary transformer windings with different initial phases (j The device contains main capacitors 1 and 2, thyristors 3 and 4, the first bridge on controlled valves 5-12, transformer 13, the primary primary winding 14 of which is included in the diagonal of the first bridge, the open ends of another diagonal through which the corresponding thyristors 3 (4) and main 1 (2) are connected to the input terminals of the device, an additional 15 and the secondary 16 windings of the transformer, auxiliary capacitors 17 and 18, the second bridge on controlled valves 19-22. At this additional winding 15 of the transformer 14 is connected via the second bridge to controlled valves 19-22 with input terminals, and auxiliary capacitors 17 and 18 are connected between the outputs of one of the diagonals of the second bridge and the common connection point of one of the terminals of the auxiliary winding 15 and the corresponding input terminal of the device, 1-. The inductance of the primary main winding 14 entering the discharge circuit of the main capacitors 1 and 2, and the capacitance of these capacitors, as well as the inductance of the primary additional winding 15 entering the discharge circuit of the auxiliary capacitors 17 and 18, and the capacitance of these capacitors are chosen: The fact that the discharge is oscillatory in nature and the frequency of the currents flowing respectively through the primary primary and secondary windings is equal to the network frequency, and the phase shift between the currents of these windings can vary automatically from 0 to 180 to 270 sec. oschyu fan control unit depending upon a level of the output voltage. The device works as follows. In the positive half-period of the network voltage (Fig. 2a), at time tg, thyristors 3 and 19 open, and from this point until time t, the capacitors 1 and 17 are charged to the amplitude value of the network voltage with the polarity shown in FIG. 1. At time t {the charge process of the capacitors 1 and 17 is stopped and the thyristors 3 and 19 are closed. Subsequently, the charged main capacitor V is discharged to the primary main winding 14 of the transformer 13 when valves 5 and 6 are opened, and the charged auxiliary capacitor 17 to the primary additional winding 15 of the transformer 13 when the valve 21 is opened. At the same time, the primary windings 14 and 15, the positive half-waves of the current flow (Fig. 2b, c). The time of opening the valve 21 in the range from the time t, j to the time t (Fig. 2a), while the opening time of the valves 5 and 6 remained constant, t, (Fig. 2, and the initial phase of the positive half-wave of the current additional winding T5 relative to the positive half-wave current of the primary primary winding 14 from (|) 0 ° to C) 90 ° (Fig.2 6, Z). At the end of the positive half-wave in the windings, the valves 5, 6 and 21 are closed, and at the same time, the valves 7 are opened; 8 and 22 and similarly, negative half-waves of current (phi; d.25, &) from the discharge of capacitors 2 and 18, formed from the time t to the modulation tg (figure 2) through thyristors respectively 4 and 20 to the amplitude value of the network voltage with the polarity indicated in FIG. 1. 284 If instead of valves 5, 6 and 7.8 during the discharge of the main capacitors 1 and 2, open valves 9, 10 and 11, 12, respectively, then the direction of the current in the primary main winding 14 of the transformer is reversed (Fig. 2 , e), then at the same control angles of the valves 21 and 22, the initial phase of the current of the additional winding 15 may vary relative to the phase of the current of the main winding 14 from φ (270 ° (Fig. 2e)). The change of the initial phase of the alternating current in the primary additional winding 15 leads to a change in the phase of the magnetic flux created the current of this winding in the transformer magnetic core, which in turn leads to a change in the resulting magnetic flux generated by the currents of both primary windings. A change in the resulting magnetic flux leads to a change in the emf induced in the secondary winding 16 of the transformer and, accordingly, the output voltage i If the power of all capacitors the number of turns of the primary primary winding 14 is equal to the number of turns of the primary additional winding 15, then when the initial phase of the current in the primary complements winding 14 from O Roif90, the output voltage can vary smoothly from LG to U (Qn, where nol (nominal voltage, while changing the initial phase from 1) 1 180 to (g / 270 output voltage can vary from O to U, which leads to a significant expansion of the output voltage control range. The shape of the output voltage is close to sinusoidal over the entire control range. In this case, with respect to the power supply network, the device itself is a capacitive load, and, therefore, it can transmit reactive power to the network, which improves its energy performance.

one

Gz

te

f

a.

h

Js

Tif

iS

H-180

: v-z70

Well

Claims (1)

DEVICE FOR REGULATING VARIABLE VOLTAGE, containing a transformer, the primary main winding of which is included in the diagonal of the first bridge on controlled bidirectional valves, the open ends of the other diagonal of which are connected to the input terminals through the corresponding thyristors and main capacitors, characterized in that, in order to expand the regulation range and improving the shape of the output voltage curve, it is equipped with a second bridge on unidirectional controlled valves and two auxiliary condes Satoru, and a transformer - additional winding connected to the input terminals through a second bridge between outputs one of which is diagonal and the common connection point of one of the terminals and the respective additional winding input terminal included auxiliary capacitors. U2 (V 10S1628