SU851361A1 - Device for regulating three-phase voltage - Google Patents

Description

one

The design relates to electrical engineering, in particular, to converter technology, and can be used, for example, in controlled three-phase voltage sources with a close to sinusoidal form of input and output currents,

Closest to the proposed device for controlling three-phase voltage, containing a phase transformer with a switched transformation ratio and two groups of terminals for phase-to-voltage connection, the first of which is connected to the windings of the phase-transformer, and the second group is connected to a three-phase power network fl}.

A disadvantage of the known device is the significant weight and size parameters due to the large mass of the phase transformer and the limited possibilities of regulation, in particular, with the release of current.

The circuit of the invention is the expansion of functional capabilities and the reduction in weight and size parameters of the device.

The goal is achieved by the fact that: an inter-phase 11 transformer

performed on one core according to the scheme of an autotransformer with two sectioned and connected in series-according to semi-windings, each pin of the first of which, except for its beginning, is connected to the three, and the second half-winding - with two pin of the first

10 groups, respectively, and the beginning of the first half winding - with one of the conclusions that are not connected with the second half winding, at least through one thyristor key.

15

FIG. 1 shows a functional diagram of the device; in fig. 2 timing diagrams explaining how the device works.

20

The device contains a three-phase power supply network 1, a load 2, a switch 3, a phase-to-phase transformer (autotransformer) 4, a winding 5-7 of the phase-to-phase transformer 4, made in the form of the first 5-7 and the second 6-7 pb-windings; pins 8, 9 and 10, 11 of the first and second semi-windings 5-6 and 6-7, respectively, bidirectional thyristor switches 12-24 of switch 4, the first and second groups of terminals 25-27 and 28-30 for connecting the load 2, respectively .

and - voltage curve of the phase A of the three-phase mains;

Uj p curves of potential voltages at load 2, corresponding to different transformation ratios of the autotransformer 4} p – p - switching functions of the corresponding thyristor switches 12-24 of switch 3; - phase voltage curve

and.

CA A of load 2 is formed of six sinusoids at the closure of the 1224 triac switches according to the switching functions.

The device works as follows.

After connecting the three-phase mains supply 1 and the load 2 to the terminals 25-27 and 28-30 of the first and second groups, respectively, the interphase autotransformer 4, which has in each phase, depending on the numbers of the included thyristor switches 12-, turns on 24, winding with a variable number of turns, iT. e.

() K-5 7-in 7-L

. w lt) vw,., v j .. ,,,,,

C 7-Q V 7-9 7-fO

With the disconnected state of all the thyristor switches 12-24 switch 3, the voltage at load 2 is zero, and when connecting terminals 2527 of the first group to any one of conclusions 5-11, the winding of the auto-transformer 4 turns out to be short-circuited and the voltage at load 2 is equal to power supply network.

During the supply period, the transformation ratio of the autotransformer 4 in a certain sequence several times, as shown in Fig. 2, in accordance with the switching functions given above, can be formed during the load phase 2 a voltage from several sinusoids with different amplitudes and phases selected.

In addition, each ratio of the number of turns in each phase corresponds to one of the possible voltage curves at one of the phases of the load (figure 2),

Claims (1)

Invention Formula A device for controlling a three-phase voltage, containing an inter-phase transformer with a switched transformation ratio, and two groups of leads for phase-to-phase connection of the load, the first of which is connected to the windings, an interphase transformer, and the second group is connected to a three-phase power network, characterized in that expanding functional capabilities and reducing weight (bariters, interfacial the transformer is made on one core according to the scheme of an autotransformer with two sectioned and connected in series-in accordance with the half windings, each output of the first of which, except its beginning, is connected to three and the second half winding through the corresponding bi-directional thyristor key, respectively, but the beginning of the first semi-winding is with one of these pins disconnected from the second semi-winding through at least one thyristor key. Information sources, taken into account in the examination 1. Power Apparatus and Systems, 1956, 26, p. 865, FIG. 3 fJ / If / Sh R 6 05 one G U- L- I I 6 6f Off Ca.