RU2011280C1 - Inverter - Google Patents

Abstract

FIELD: electrodeposition. SUBSTANCE: device has transformer 4 and interphase reactor 5. Transformer secondary windings 7-9 and 10-12 are connected to direct and inverse three-phase stars, whose neutral conductors are connected to one of the output leads for connection with load 3. The neutral conductor of the direct star is formed by the phase beginnings, and that of the inverse star-by the phase ends. The reactor has magnetic circuit 14 and three three-phase windings 15-17, 18-20 and 20-23, the first winding being short-circuited. The beginnings of the reactor second winding are connected to the beginnings of the direct star. The ends of the reactor third winding are connected to the ends of the inverse star. Taps are made from the ends of the second and beginnings of the third windings of the reactor to connect the input of rectifier 2, whose output is connected to another tap. EFFECT: facilitated procedure. 1 dwg

Description

 The invention relates to electrical engineering, namely to power converting equipment, and can be used in installations of electroplating, electrolysis, to power the contact network of urban transport, etc.

 Known Converter (1) containing a transformer, surge reactor and rectifier. The secondary windings of the transformer are connected to the forward and reverse stars.

 At the direct star, the beginnings of the three phases are derived, and the ends are connected to the zero line of the direct star. At the reverse star, the ends of three phases are derived, and the beginnings are connected to the zero bus of the reverse star. The beginnings and ends of the forward and reverse stars, respectively, are connected to the rectifier. The direct star zero bus is connected to the beginning of the surge reactor winding, the end of which is connected to the reverse star zero bus. From the midpoint of the winding of the equalization reactor, dividing it into two branches, a conclusion is drawn for connection with the load.

 The described device has a significant drawback: due to the asymmetry of the control pulse of the converter, different switching reactants at the secondary windings of the transformer and a distorted system applied to the primary winding of the transformer, the load current between the direct and reverse stars is divided unevenly, which requires additional copper consumption to the transformer and reduces it Efficiency. In addition, the magnetic circuit of the equalization reactor is saturated, which leads to an increase in the equalization current and to an additional decrease in the efficiency of the converter.

 This drawback is eliminated in the device (2) containing a transformer, interphase reactor and rectifier. The transformer contains two secondary windings, one of which is connected to a direct star, and the other to a reverse star.

 The interphase reactor contains a magnetic circuit and three three-phase windings, the first of which is short-circuited. The ends of the star of the transformer are connected to the beginning of the second winding of the reactor, and the beginning of the back star are connected to the ends of the third winding of the reactor. The ends of the second reactor winding and the beginning of the third reactor winding are connected to the zero bus.

 From the zero bus, a conclusion is made for connecting to the load. From the beginning of the direct star and the ends of the backward star, conclusions are made connected to the rectifier.

 The described device requires an increased consumption of copper for connections between the ends of a direct star and the beginnings of the second winding of the reactor, as well as between the beginnings of the reverse star and the ends of the third winding of the reactor.

 The aim of the invention is to increase the efficiency of the device by simplifying the design and improving overall dimensions.

 This goal is achieved by the fact that in the AC-to-DC converter containing a transformer with a three-phase primary winding connected to the input terminals for connecting the mains and two three-phase secondary windings, the first of which is connected in a direct and the second in a reverse star, zero the conclusions of which are connected to the first output terminal for connecting the load, and the zero output of the first winding is formed by a common point of connection of its ends, and the zero output of the second winding is formed by a common point it began to be connected, a rectifier consisting of six groups of valves, one of the same terminals of the power electrodes of which are combined into a common point connected to the second output terminal, and an interphase reactor, on the magnetic circuit of which there are three three-phase windings, the first of which is short-circuited, the first secondary winding is proposed connect the transformer with the beginnings of the second winding of the specified reactor, connect the second secondary winding of the transformer with the ends of the third winding of the reactor, and free conclusions Torah and third reactor coil connected to the free terminals of power electrodes of the corresponding groups of the rectifier valves.

 In the inventive device, there is no need to output the ends of the direct star and the beginnings of the reverse star beyond the transformer, and the conclusions of the beginnings of the direct star and the ends of the reverse star beyond the transformer are the same both in the claimed object and in the prototype.

 The drawing shows a schematic diagram of a six-phase converter. The converter contains an induction device 1, a rectifier 2 and a load 3.

The induction device comprises a transformer 4 and an interphase reactor 5. The transformer 4 contains a primary three-phase winding 6 and secondary windings, one of which is connected to a direct three-phase star - 7, 8, 9, and the other - 10, 11, 12 - to a reverse star. The beginnings of a direct star are designated - a ₁ ¹ , b ₃ ¹ , c ₅ ¹ ; respectively, the ends of a direct star are x ₁ ¹ , y ₃ ¹ and z ₅ ¹ . The beginnings of the reverse star are designated - x ₄ ¹ , y ₆ ¹ , z ₂ ¹ ; accordingly, the ends of the reciprocal star are a ₄ ¹ , b ₆ ¹ , c ₂ ¹ . From the ends of the direct star (7, 8, 9), connections are made to the zero bus 13 (x ₁ ¹ X ₁ ; y ₃ ¹ Y ₃ ; z ₅ ¹ Z ₅ ). From the beginning of the reverse star 10, 11, 12 to the zero bus 13, connections x ₄ ¹ X _{4 are made} ; y ₆ ¹ Y ₆ ; z ₂ ¹ Z ₂ .

The interphase reactor 5 consists of a magnetic circuit 14 and three three-phase windings, the first of which is 15, 16, 17 short-circuited. The beginnings of the second winding (18, 19, 20) of the reactor are connected to the beginnings a ₁ ¹ , b ₃ ¹ , c ₅ ^{1 of the} direct star 7, 8, 9. The ends of the third winding (21, 22, 23) of the reactor are connected to the ends a ₄ ¹ , b ₆ ¹ , c ₂ ^{1 of the} reverse star 10, 11, 12.

 From the zero bus 13, the conclusion 24 is made for connecting the transformer to the load. From the ends of the second winding (18, 19, 20) and from the beginning of the third winding (21, 22, 23) respectively made conclusions 25, 26, 27 and 28, 29, 30 for connection with the rectifier 2. The rectifier contains six groups of valves, each of which includes one valve, respectively 31, 32, 33, 34, 35, 36. (In general, the number of valves in each group can be 2, 3, or more, depending on the voltage and load current).

 The device operates as follows. The mains voltage is supplied to the input terminals A, B, C. The load current 3 flows through two valves, one of which is connected to one of the phases of the reverse star, and the other to one of the phases of the direct star. The valves are unlocked in the order of their numbering indicated on the drawing. At the same time, during the voltage period of the supply network, pairs of valves conduct current in the following order: 31.32; 32.33; 33.34; 34.35; 35.36; 36.31.

 Let us assume that the current of a direct star (7, 8, 9) increased compared with the current of a reverse star (10, 11, 12), while maintaining the load current unchanged when the current is conducted by the first pair of valves (31.32). Then the current in phase 18 of the second reactor winding is greater than the current in phase 23 of the third reactor winding (the direction of the currents is indicated by arrows in Fig. 1). In this case, the current in phase 15 of the first winding increases. Phase 15 is connected in series with phase 17 of the first winding of the reactor. Therefore, the current also increases in phase 17. This will lead, according to the law of the total current, to increase the current in phase 23 of the third winding of the reactor. An increase in current in phase 23 will lead to a decrease in current in phase 18, since the load current has not changed, and valves 31 and 32 operate in parallel.

 A similar phenomenon will occur during the operation of other pairs of valves (32.33; 33.34, etc.).

 The process of decreasing the current in the direct star and increasing the current in the reverse star of the transformer will occur until the currents in both stars of the transformer are equal.

In the prototype, the second winding of the reactor (18, 19, 20) is connected between the ends of the direct star x ₁ ¹ , y ₃ ¹ , z ₅ ¹ and zero bus 13, and the third winding of the reactor (21, 22, 23) is between the beginnings of the reverse star x ₄ ¹ , y ₆ ¹ , z ₂ ¹ and zero bus 13.

When the reactor is located outside the transformer, this requires an increased copper consumption in the prototype due to the sections between the ends of the direct star x ₁ ¹ , y ₃ ¹ , z ₅ ¹ and the beginnings of the second winding of the reactor, as well as due to the sections between the beginnings of the reverse star x ₄ ¹ , y ₆ ¹ , z ₂ ¹ and the ends of the third reactor winding.

When the interfacial reactor is located in the same tank with the transformer, the claimed object also has a gain compared to the prototype in the consumption of materials for the connections between the ends of the direct star x ₁ ¹ , y ₃ ¹ , z ₅ ¹ and the beginnings of the second winding of the reactor, as well as between the beginnings of the reverse star x ₄ ¹ , y ₆ ¹ , z ₂ ¹ and the ends of the third reactor winding. (56) Berkovich E.I., Kovalev V.N. et al. Semiconductor rectifiers. M., Energy, 1978, p. 82, 83, fig. 2-17.

 U.S. Patent No. 4,831,352, cl. H 01 F 33/00, 1989.

Claims (1)

 AC VOLTAGE CONVERTER TO DC, containing a transformer with a three-phase primary winding connected to the input terminals for connecting the mains supply, and two three-phase secondary windings, the first of which is connected to the direct and the second to the reverse of the star, the zero conclusions of which are connected to the first output output to connect the load, and the zero output of the first winding is formed by a common point of connection of its ends, and the zero output of the second winding is formed by a common point of connection of its beginnings, a rectifier, with consisting of six groups of valves, the same terminals of the power electrodes of which are combined into a common point connected to the second output terminal, and an interphase reactor, on the magnetic circuit of which there are three three-phase windings, the first of which is short-circuited, characterized in that, in order to simplify the design and improvement of overall dimensions, the first secondary winding of the transformer is connected to the beginning of the second winding of the reactor, the second secondary winding of the transformer to the ends connected to the ends of the third reactor branches, and the free terminals of the second and third reactor windings are connected to the free terminals of the power electrodes of the respective rectifier valve groups.