SU970341A1 - Three phase voltage adjustmentd device - Google Patents

Description

(5) DEVICE FOR REGULATING THREE-PHASE VOLTAGE

one

The invention relates to electrical engineering, in particular to converter equipment, and can be used, for example, to regulate or stabilize the voltage of a power supply.

A device for regulating a three-phase voltage is known, comprising two valve bridges closed at a storage capacitor and connected in series in alternating current to the load circuit 1.

In this case, the successive switching of the valve bridges is carried out with the help of a trans (1urmator, the primary winding of which is connected to the load terminals and the alternating current leads of one of the bridges, and the secondary winding is connected to the alternating current leads of the second bridge.

The device provides regulation; voltage at a sufficiently small degree of distortion. It does not have an increased valve power due to the series connection of bridges, and additional losses associated with the full load current flowing around each bridge.

Closest to the present invention is a device for regulating a three-phase voltage containing two transformers, the first windings of which are connected to the input terminals and the AC terminals.

10 corresponding valve bridges, with the second winding of a transformer. Having the number of turns 3 times more, connected in a triangle, and the other transformer - in

15 star 2.

A disadvantage of the known device is the increased mass-dimensional indicators associated with an increase in the power of transformers equal to the power of the load.

Claims (2)

The purpose of the invention is to reduce the weight and size parameters. The goal is achieved by the fact that a device for controlling three-phase voltage containing two transformers, the first windings of which are connected to the input terminals and AC terminals of the respective valve bridges, while the second winding of one transformer having tm times more times is connected a delta, and another transformer into a star, has two pairs of terminals for phase-wise connection of the load, one of which is connected to the power supply source directly, and the other pair is about razovana output terminals connected to first terminals of the transformer windings, second windings are interconnected in a closed loop. FIG. 1 and 2 shows a functional diagram of a device with a capacitive and inductive drive, respectively; in fig. 3 is a vector diagram of the main harmonic voltages for a variant with a capacitive drive (Fig. 1). The device contains two three-phase transformers 1 and 2, the first windings 3 of which are connected between the second pair of terminals k-6 for phase-wiring of the load and alternating current terminals valve bridges 7 and 8, and their second windings E, differing with the number of turns in Oz times, are interconnected in a closed loop, capacitive (Fig. 1) or inductive (Fig, 2) drive I) connected at the exit of the valve bridges 7 and 8, the first pair of pins 11-13, is connected Directly with the power supply source, load It, When using capacitive circuits (Fig. 1), valve bridges 7 and 8. are made of counter-parallel controlled and uncontrolled gates, and when using an inductive storage device short-circuiting the outputs of bridges from controlled valves Consider the operation of a device with a bone storage device (Fig. 1). Due to the connection of transformer windings shown in FIGS. 1 and 2, their primary currents are 30 e relative to each other relative to each other. hail. Therefore, the gates of bridges 7 and 8 such must be switched with a 30 ° offset. When switching the bridge gates, an alternating-current voltage is created at their AC terminals, the fundamental harmonic of which is ahead of the current by an angle of 90. Then the display in FIG. 2 is a vector diagram constructed for the active load, where 3, U.J, and 3r are the primary currents of transformers 1 and 2 and the load It; U and UH are the mains voltage and load and and and .2. variable voltages (phase) at the input of bridges 7 and 8, and ,, and, and U – tj, alternating voltages on the primary windings of 3 transformers 1 and 2. From the vector diagram we find | IJ | lUT2HJ3sin, 26 out So as in the limit at, (i, we get U 0-by and Ti.mdx T2 wax Next we find i 2 - f H-FW-5 H From here we get the calculated power of the transformers on the fundamental harmonic, 13b PH. В 2 It is shown that the higher harmonics contained in the alternating voltage of the valve bridges, transforming into the secondary circuit, are in different phase arrangements x. So, harmonics with measurements of 12 K ± 1, K 1,2,3, ... (5 because the secondary circuit of the transformers is short-circuited, the transformers for these harmonics will be in short circuit mode and in On the primary windings, these harmonics will not be contained. For the remaining harmonics in the secondary circuit in the pro- tive phase, the transformers operate at idle and these harmonics will be contained in the primary voltage. With the highest harmonics, the transformer power is calculated is equal to. 1p "mid 2p" mid P Thus, the total transformer power in the proposed device is 3 times less than in device 2 and significantly less than in device 1. Similar relations are obtained for devices with inductively by the accumulator (FIG. 2) and with closed bridges. Claims An apparatus for regulating three phase voltages comprising two transformers, the first windings of which are connected to the input terminals and alternating current terminals of the respective valve bridges, the second winding of one transformer connected to a star, and the second winding of another transformer having a number of turns Uz times larger, connected in a triangle, about t and h a. shch 6 e so that, in order to reduce the weight and size indicators, it has two pairs of terminals for phase-wise load connection, one pair and from which they are connected to the source of supply voltage directly, and the other pair is formed by output terminals connected to one of the terminals of the first windings of transformers, the second windings of which are interconnected in a closed loop, - Sources of information taken into account during the examination 1. Authors USSR certificate in application N 2713123/07, cl. G OSF 1/20, 2. USSR Author's Certificate No. 29% 356/07, cl. G 05 F 1/2, at FIG. 2 fig-3