SU1343522A1 - A.c.to d.c.voltage converter - Google Patents

Abstract

The invention is FOSIC for electrical engineering and can be used to supply loads that require stepwise voltage control, for example, at traction substations. The purpose of the invention is to increase the efficiency with stepwise voltage regulation. The positive effect is due to the introduction of booster transformers 4, the network windings 3 of which are connected in a star. The connection of the winding 3 to the winding 2 of the main. the transformer ensures the phase matching of the voltage of the winding sections 6 with the actual or equivalent phase voltage of the winding 2 of the main transformer. 2 Il. (L co 4 SO e th th

Description

The invention relates to electrical engineering and can be used to supply loads that require stepwise voltage control, for example, at a substation.

The purpose of the invention is to increase the efficiency with stepwise voltage regulation.

The connection of the power winding 3 of the transformer 4 connected in a star. 1 shows the principle Q doo, to the valve winding 2 main

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thirty

converter circuit; in fig. 2 - vector diagrams of the voltage of the valve windings of the main transformer, network and valve windings of booster transformers, where 15 Uj, and, are the phase and line voltages of the valve windings of the main transformer; Ug - phase voltages of the network windings of a booster transformer; U, Uj, .. ,, U ,, are the voltages of the valve windings.

The converter (Fig. 1) contains the main winding 1 of the main transformer - connected to the three-phase system, valve, windings 2, connected to the network windings 3 of the additional booster transformer 4 and to one of the three-phase controlled valve bridges 5 in parallel (or in series) The valve windings 6 of booster transformer 4, which have taps, are connected in series with each other to the corresponding phases of windings 2, and by taps to additional controlled valve bridges 5. All bridges 5, connected to one booster transformer 4, are connected in parallel and form a unified cell 7. The converter elements of the bridges 5 are controlled by the control system 8.

The Converter operates as follows.

The first voltage level of the multi-pulse converter is obtained by switching on the converter bridges 5 connected to the windings 2. The conversion bridge of the first control stage can be performed on diodes. The voltage increase by steps is carried out by switching on the control system 8 of the respective bridges 5. All the cells 7 can be interconnected both in series and in parallel. The voltage of the winding 3 of the transformer 4 of the transformer ensures that the voltage of the winding sections 6 coincides with the actual or equivalent phase voltage with a clear winding 2 of the main transformer. Therefore, connecting the same number of valve sections: windings 6 of booster transformer 4 to valve windings 2 of the main transformer does not change the shear angles between three-phase voltage systems at all stages of regulation and retains a multipulse transformation, which is shown by vector diagrams (Fig. 2), where The vectors U coincide with the real and equivalent phase voltages of winding -2. This is the formation using vectors

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UD, and

ten

and

8A

45

Claims (2)

Invention Formula AC to DC converter containing a main transformer with a mains and valve windings, which are connected in a star, a triangle and a sliding triangle, and connected to the main corresponding three-phase valves connected to the DC output in series, differ- With teMr that, in order to increase the efficiency with step-by-step voltage regulation, volt- auxiliary transformers with mains and valve windings were additionally introduced, and the valve coil with them There are tap-offs according to the number of voltage regulation steps connected to additionally introduced controlled valve bridges, the network windings of each booster transformer are connected in a star and connected by free leads to the corresponding AC inputs of the main three-phase valve bridges and to the beginnings of their valve winding. It is in accordance with certain voltages with the voltage of the sections of the winding 6, depending on the transformation ratios between the windings and their sections. Connect the power winding 3 of the transformer 4, connected in a star, to the valve winding 2 of the main transformer provides phase matching of voltage of winding sections 6 with real or equivalent phase voltage. Clear winding 2 of the main transformer. Therefore, connecting the same number of valve sections: windings 6 of booster transformer 4 to valve windings 2 of the main transformer does not change the shear angles between three-phase voltage systems at all stages of regulation and retains a multipulse transformation, which is shown by vector diagrams (Fig. 2), where U vectors coincide with real and equivalent winding phase voltages - 2. Such is the formation using vectors UD, and ten and 8A five 0 0 five five Invention Formula AC to DC converter containing a main transformer with a mains and valve windings, which are connected in a star, a triangle and a sliding triangle, and connected to the main corresponding three-phase valves connected to the DC output in series, differ- With teMr that, in order to increase the efficiency with step-by-step voltage regulation, volt- auxiliary transformers with mains and valve windings were additionally introduced, and the valve coil with them There are tap-offs according to the number of voltage regulation steps connected to additionally introduced controlled valve bridges, the network windings of each booster transformer are connected in a star and connected by free leads to the corresponding AC inputs of the main three-phase valve bridges and to the beginnings of their valve winding.