RU2321149C1 - Transformer of alternating voltage to constant voltage with 24-multiple pulsation frequency - Google Patents

Abstract

FIELD: electric engineering.

SUBSTANCE: transformer of alternating voltage to constant voltage with 24-multiple pulsation frequency is meant for transformation of alternating voltage to constant voltage for powering traction loads of electric transportation means and electro-technological plants powered by constant current. Device contains two transformer sources (1,2), which generate two six-phased EMF systems, phase-shifted relatively to each other for fifteen electric degrees and represented by contacts of supplies 1a, 1b, 1c, 1a', 1b', 1c' and 2a, 2b, 2c; 2a', 2b', 2c', and also twenty four valves (3...26), which constitute a six-valve ring, valves (3, 10, 13, 18, 21, 25) of which are connected by electrodes of the same name; points of connection of anodes of valve pairs (4,25; 10,13; 18,21) are connected, respectively, to contacts 1a, 1b, 1c of supply (1) and to anodes of valves (26,11,19), cathodes of which are connected, respectively, to contacts 2a', 2b', 2c' of supply (2); points of connection of cathodes of valve pairs (13,18;21,25;4,10) are connected, respectively, to contacts 2a, 2b, 2c of supply (2) and to cathodes of valves (16,24,8), anodes of which are connected, respectively, to contacts 1a', 1b', 1c' of supply (1), where each contact of supply (1) is connected to cathode of one of diodes (3,6,12,14,20,22) of six-valve anode start, common unit of which forms the negative output contact (27) of the device, and each contact of supply (2) is connected to anode of one of diodes (5,7,9,15,17,23) of six-valve cathode star, common unit of which constitutes the position output contact (28) of the device; to contacts (27,28) the load (29) is connected.

EFFECT: reduced mass-dimensional characteristics and increased efficiency.

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Description

The invention relates to electrical engineering and power converting equipment and can be used as an AC to DC converter for supplying traction loads of electric vehicles, supplying electrotechnological and other installations.

Known AC to DC converter with m-fold ripple frequency (m = 24 is considered) of a serial-parallel type, containing 12 sources of arbitrary EMF and 24 valves connected to two six-cell valve bridges connected in series [A.S. USSR No. 917280. AC / DC valve converter. / A.M. Repin - Application. No. 2938434 / 24-07; declared 06/11/80; publ. 03/30/82; Bull. No. 12].

The disadvantages of this source are the large number of transformers used, since in order to preserve the parametric symmetry of the resulting voltage generation circuits, with the applied configuration of the secondary windings, the source must contain at least four three-phase transformers, and accordingly, large weight and size indicators, as well as relatively large power losses in the valves sequentially streamlined by the load current.

, считается от одноименного зажима каждой обмотки, причем первичные обмотки трансформатора одного преобразователя соединены в «звезду», а второго в «треугольник», а выходы всех выпрямителей включены параллельно.Also known is an AC to DC converter with a 24-fold ripple frequency [US Pat. No. 2219647 of the Russian Federation. AC / DC Converter / Yu.S. Igolnikov - 2002105589/09; declared 03/01/02; publ. 12/20/03; Bull. No. 35], containing a three-phase transformer, the secondary windings of which are connected in a triangle and each of them is equipped with two taps that are connected to the AC diagonals of two bridge rectifiers connected in parallel in the input, and the source is equipped with an additional same converter, the secondary windings of which are connected to the same triangle, while the bends of both transformers are made from parts of the winding, which are in the ratio

, is counted from the same clamp of each winding, and the primary windings of the transformer of one converter are connected to a "star", and the second to a "triangle", and the outputs of all rectifiers are connected in parallel.

The disadvantages of this converter are the large weight and size indicators and the use of secondary windings in it, parts of which have three values of the number of turns, which at low numbers of turns (at high power and relatively low rectified voltage) leads to an increase in structural asymmetry due to the limited ability to provide the calculated ratio between the numbers of turns and thereby reduces the efficiency of conversion of electrical energy.

, а два вывода первичной обмотки одного из трансформаторов присоединены к трехфазной сети с транспозицией по отношению к присоединению идентичных выводов первичной обмотки другого трансформатора, причем вторичные обмотки в каждом трансформаторе выполнены звездой и треугольником и выводы каждой из них соединены с одним из трехфазных вентильных мостов одной из пар мостов, а при соединении пар мостов параллельно обеспечивается эквивалентное 24-пульсное выпрямление.Closest to the invention adopted as a prototype is an AC to DC converter with a 24-fold ripple frequency (two-stage execution is considered) [Yatsenko A.A. Application of the "moving triangle" circuit in multiphase converters. // Electricity. - 1982. - No. 7. - P.17-24, (Fig. 2, a)], containing twenty-four valves, of which two pairs of valve bridges are connected in series in each pair, and two identical three-phase transformers, the primary windings of which are connected according to the “sliding triangles” scheme ", The ratio of the parts of the windings making up the triangles in which, to the parts of the windings making up the extended sides, is

and the two terminals of the primary winding of one of the transformers are connected to a three-phase network with transposition with respect to the connection of the identical terminals of the primary winding of the other transformer, the secondary windings in each transformer made by a star and a triangle and the conclusions of each of them are connected to one of the three-phase valve bridges of one of pairs of bridges, and when connecting pairs of bridges in parallel, equivalent 24-pulse rectification is provided.

The disadvantages of this converter are large weight and size indicators and insufficiently high efficiency due to the relatively large power losses in the valves.

The objective of the invention is the creation of an AC to DC converter with a 24-fold ripple frequency, which has lower overall dimensions and higher efficiency.

, а два вывода первичной обмотки одного из трансформаторов присоединены к трехфазной сети с транспозицией по отношению к присоединению идентичных выводов первичной обмотки другого трансформатора, при этом из частей вторичных обмоток в каждом трансформаторе сформирован источник шестифазной системы ЭДС, образованный звездой и обратной звездой, соединенными нулевыми точками, причем части обмоток звезды и части обмоток обратной звезды находятся в соотношении

, а из шести вентилей сформировано вентильное кольцо, вентили которого соединены между собой только одноименными электродами, при этом каждая из трех точек соединения, образованных электродами одного наименования, подключена к одному из выводов звезды одного источника, а каждая из трех точек соединения, образованных электродами другого наименования, подключена к одному из выводов звезды другого источника, причем каждая точка соединения вентилей кольца, подключенная к выводу звезды одного из источников, подключена также к точке соединения разноименных электродов двух вентилей, образующих вентильную ячейку, один крайний электрод которой, имеющий наименование, отличное от наименования электродов вентилей кольца в точке соединения с кольцом данной ячейки, соединен с выводом обратной звезды другого источника, причем этот вывод имеет наименование, аналогичное наименованию вывода звезды источника, подключенного к данной точке кольца, а второй крайний электрод ячейки подключен к соответствующему выходному выводу устройства, при этом каждый из выводов обратных звезд, к которому присоединен электрод вентиля ячейки, соединен с электродом другого наименования незадействованного вентиля, второй электрод которого присоединен к соответствующему выходному выводу, причем выводы звезд, имеющие одинаковое наименование, подключены к диаметрально противоположным точкам соединения вентилей кольца.This problem is achieved by the fact that the AC to DC converter with a 24-fold ripple frequency contains twenty-four valves and two identical three-phase transformers, the primary windings of which are connected according to the "sliding triangles" scheme, the ratio of the parts of the windings that make up the triangles in which, to the parts of the windings constituting the extended sides equals

and the two leads of the primary winding of one of the transformers are connected to a three-phase network with transposition with respect to the connection of identical leads of the primary winding of the other transformer, while a source of a six-phase EMF system formed by a star and a reverse star connected by zero points is formed from the parts of the secondary windings in each transformer moreover, parts of the windings of the star and parts of the windings of the reverse star are in the ratio

and a valve ring is formed from six gates, the gates of which are interconnected by electrodes of the same name, with each of the three connection points formed by the electrodes of the same name connected to one of the terminals of the star of one source, and each of the three connection points formed by the electrodes of the other names connected to one of the star terminals of another source, and each connection point of the ring valves connected to the star terminal of one of the sources is also connected to the connection point the opposite electrodes of two valves forming a valve cell, one extreme electrode of which, having a name different from the name of the valve electrodes of the ring at the connection point with the ring of this cell, is connected to the reverse star terminal of another source, and this terminal has a name similar to the name of the star terminal a source connected to a given point of the ring, and the second extreme electrode of the cell is connected to the corresponding output terminal of the device, with each of the outputs of the reverse stars to the cat The cell valve electrode is connected to each other, connected to the electrode of another name for the idle valve, the second electrode of which is connected to the corresponding output terminal, the star terminals having the same name are connected to diametrically opposite points of connection of the ring valves.

Figure 1 shows a circuit diagram of the proposed Converter; figure 2 is a vector diagram of the voltage sources of the EMF and the resulting voltage; figure 3 - circuit flow of the load current in each of the twenty-four phases of the conversion process.

The AC to DC Converter with a 24-fold ripple frequency (Figure 1) contains two transformer sources 1 and 2, forming two six-phase EMF systems, phase-shifted by fifteen electrical degrees and represented by the conclusions of sources 1a, 1c, 1s, 1a ', 1c', 1c 'and 2a, 2c, 2c; 2a ', 2c', 2c ', as well as twenty-four valves 3 ... 26, of which a six-valve ring is formed (valves 4, 10, 13, 18, 21, 25), the valves of which are connected by the same electrodes; points of connection of the anodes of the pairs of valves 4, 25; 10, 13; 18, 21 are connected, respectively, with the terminals 1a, 1b, 1c of the source 1 and with the anodes of the valves 26, 11, 19, the cathodes of which are connected, respectively, with the terminals 2a ', 2b', 2c 'of the source 2; the connection points of the cathodes of the pairs of valves 13, 18; 21, 25; 4, 10 are connected, respectively, with the terminals 2a, 2b, 2c of the source 2 and with the cathodes of the valves 16, 24, 8, the anodes of which are connected, respectively, with the terminals 1a ', 1b', 1c 'of the source 1, and each terminal of the source 1 connected to the cathode of one of the diodes (3, 6, 12, 14, 20, 22) of a six-valve anode star, the common node of which forms a negative output terminal 27 of the device, and each terminal of source 2 is connected to the anode of one of the diodes (5, 7, 9 , 15, 17, 23) of a six-valve cathode star, the common node of which forms a positive output terminal 28 of the device; to the conclusions 27, 28 connected load 29.

The principle of operation of the device (Figure 1) is illustrated by vector diagrams of the voltage of the sources of EMF and the resulting voltage (Figure 2) and the sequence of circuits of the load current in each of the twenty-four phases of the rectification process (Figure 3).

. При таком соотношении обеспечивается динамичное формирование результирующих напряжений, модули векторов которых равны и сдвинуты друг относительно друга на фазовой плоскости на 15 эл. град. Условно зафиксировав диаграмму напряжений первой системы и перемещая вокруг нее диаграмму напряжений второй системы, за период сетевого напряжения получим 24 вектора результирующих напряжений (Фиг.2,б). В каждом положении систем на фазовой плоскости определяются элементы вентильной конструкции, время работы этих элементов и вторичных обмоток. Для иллюстративности приведены три положения систем на фазовой плоскости (Фиг.2,в), при которых формируются векторы результирующих напряжений S1...S5, S23, S24. Весь цикл работы преобразователя представлен токопроводящими цепями на Фиг.3.Vector diagrams (Figure 2, a) show the amplitude-phase characteristics of each of the six-phase EMF systems used. The ratio of the number of turns of the windings of a star and a reverse star

. With this ratio, the dynamic formation of the resulting stresses is provided, the vector modules of which are equal and shifted relative to each other on the phase plane by 15 el. hail. Conditionally fixing the voltage diagram of the first system and moving the voltage diagram of the second system around it, for the period of the mains voltage we get 24 vectors of the resulting voltages (Figure 2, b). In each position of the systems on the phase plane, the elements of the valve structure are determined, the operating time of these elements and secondary windings. For illustrative purposes, three positions of the systems on the phase plane are shown (Figure 2, c), at which the resulting voltage vectors S1 ... S5, S23, S24 are formed. The entire cycle of the Converter is represented by conductive circuits in Figure 3.

Based on the analysis of vector diagrams, the windings of three-phase stars included in six-phase stars are in a conductive state of 180 el. hail., and windings of reverse stars - 60 el. hail. The valves of the anode and cathode of the valve stars 5, 6, 9, 14, 17, 22 work 90 el. hail. over a period; other valves of the anode and cathode stars and valves 8, 11, 16, 19, 24, 26 - 30 e. hail. The conduction angle of the valves of the ring 4, 13, 21 is 45 el. hail., and valves 10, 18, 25 - 15 el. hail.

The scheme of the proposed device is two-stage and the converter assembled according to this scheme provides increased consumer requirements for the quality of the rectified voltage and the consumed alternating currents at a relatively high level of constant voltage and high consumer power.

The use of secondary windings of transformers with only two numbers of turns and a different ratio between them, in comparison with the prototype, expands the choice of circuit solutions for the manufacture of secondary windings with integer numbers of turns, which is very important for powerful converters, as well as at a relatively low level of rectified voltage, when it is difficult to provide the required magnitude of structural asymmetry.

For AC-DC converters, which can, under certain assumptions, be compared with the proposed converter, it has a relatively small installed power factor. The transformers of this ring two-stage 24-pulse converter have a lower installed (typical) power S _T (relative to the load power P _d ) even compared to a transformer of a single-stage two-stage 24-pulse bridge converter without a surge reactor (1,217 · R _d against 1,249 · R _d ) , which is associated with a phase shift between the linear voltages of the secondary windings forming the resulting voltage, not 150 e. hail., like a bridge converter, and in 165 el. hail. (Figure 2, c). The installed capacity of the secondary windings of the transformers of the proposed device as a result of the optimal formation of the vectors of the resulting voltage is 1.246 · P _d , while the installed power of the secondary windings of the transformers of the prototype is 1.481 · P _d . The overall dimensions of the transformer equipment of the proposed device, thus, are reduced by almost 9%. In the load current flow circuit, only three, not four valves are connected in series, which for a certain part of consumers may be the optimal solution, since with high classes of valves the power loss in the valve design can be reduced by 25%, thereby increasing the efficiency of the converter as a whole, as shown by calculations, not less than 0.25%.

Thus, the proposed AC to DC converter with a 24-fold ripple frequency has, in comparison with the prototype, lower overall dimensions and higher efficiency.

Claims (1)

A DC to DC converter with a twenty-fourfold ripple frequency, containing twenty-four valves and two identical three-phase transformers, the primary windings of which are connected according to the "sliding triangles" scheme, the ratio of the parts of the windings making up the triangles to the parts of the windings making up the extended sides is

and the two terminals of the primary winding of one of the transformers are connected to a three-phase network with transposition with respect to the connection of identical terminals of the primary winding of the other transformer, characterized in that a source of the six-phase EMF system is formed from the parts of the secondary windings, formed by a star and a reverse star connected by zero points, and parts of the windings of the star and parts of the windings of the reverse star are in the ratio

and a valve ring is formed from six gates, the gates of which are interconnected only by the same-named electrodes, with each of the three connection points formed by the electrodes of one name connected to one of the terminals of the star of one source, and each of the three connection points formed by the electrodes of another name is connected to one of the star terminals of another source, and each connection point of the ring valves connected to the star terminal of one of the sources is also connected to a point I of the opposite electrodes of two gates forming a valve cell, one extreme electrode of which, having a name different from the name of the gate valve electrodes at the connection point with the ring of this cell, is connected to the reverse star terminal of another source, and this terminal has a name similar to the name of the star terminal a source connected to a given point of the ring, and the second extreme electrode of the cell is connected to the corresponding output terminal of the device, with each of the outputs of the reverse stars to which a cell valve electrode is connected to the rum, connected to an electrode of a different name for the idle valve, the second electrode of which is connected to the corresponding output terminal, and the star terminals having the same name are connected to diametrically opposite points of connection of the ring valves.

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