SU851694A1 - Ac-to-dc converter - Google Patents

Description

(54) AC VOLTAGE CONVERTER

one

The invention relates to a converter technique and can be used in a reversible electric drive as an AC-to-DC converter.

AC-DC converters are known, containing counter-parallel-connected rectifying bridges connected to the input pins and providing reverse ynpaBjjeHHe DC motors 1.

Such converters have a certain output power.

The closest in technical essence to the proposed AC-to-DC converter contains two groups of two series-connected controlled rectifying three-phase bridges, which are DC-connected through four reactors, the common points of which are connected to the output terminals, and AC diagonals of the indicated bridges are connected in pairs to the secondary windings of two transformers with different wiring diagrams of the windings 2.

A disadvantage of the known converter is that, with the joint control of groups of valves, the surge current can reach high values.

The purpose of the invention is to reduce surge currents with joint control.

This goal is achieved by the fact that rectifiers of different groups connected from the direct current side with the same output terminals from the alternating current side are connected to different transformers.

The drawing is a schematic diagram of the device.

Claims (2)

The primary windings of transformers 2 and 3 are connected to the AC buses 1. The secondary windings of the transformers are connected to a thyristor bridge rectifier. Each of the four rectifiers on the valves 4-11, which form the anodic and cathodic groups, respectively, 5, 7, 8, 10 and 6, 4, 9, 11 (individual rectifiers: are circled by a dashed line). The venous thistles 4, 5, 6, 7 and 8, 9, 10, 11 are connected in series and form two reversible branches. The branches are interconnected in parallel through equalizing reactors 12. The bridge rectifiers are cross-connected to the transformers, i.e. two converters in different branches, connected to the same transformer, on the DC side do not have a common point. Due to this circumstance, the emf and inductance of other rectifiers are introduced into the circuit of the surge current. So, for example, the circuit for equalizing current for the cathode group 4 and the anode group 10 (these groups are connected to one transformer 2) contains in addition to reactors 12 also a rectifier with valves 8 and 9 and their transformer 3. If valves 8 and .9 If they also connected to transformer 2 a 10, 11 to transformer 3, then there would be no other rectifier in the circuit of the balancing current. In this case, the circuit of this current would consist of valves 4, two reactors 12 and valves 8. Claims of the invention AC-to-DC converter containing two groups of two series-connected controlled rectifiers of three-phase bridges that are DC-counter-coupled - in parallel through four reactors, the common points of which are connected to the output terminals, and the diagonal of the alternating current, of the indicated bridges are connected in pairs to the secondary windings of two transformers with different connection circuits about a coil, characterized in that, for the purpose of reduction. equalization currents with coordinated control, rectifiers of different groups connected from the direct current side with the same output terminals from the alternating current side are connected to different transformers. Sources of information taken into account in the examination 1. Semiconductor rectifiers. Ed. Kovaleva M., “Energie, 1978. 2.Apter A.M. et al. Powerful thyristor rectifiers for direct current electric drives. M., “Energie, 1975 (prototype).