RU2334345C1 - Converter of ac potential into constant one with 9-fold frequency of pulsation - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: converter of the ac potential into a constant one with 9-fold frequency of the pulsation contains a three-phase transformer (1) with the group of secondary windings (2) connected according to the scheme of the first six-phase star, and the group of the secondary windings (3) connected under the scheme of the second six-phase star, and fifteen gates (4...18). Phase conclusions and, in, with the groups of windings 3, which belong to the star of the second six-phase star, are connected by three unidirectional gates (5, 11, 16) which are switched on, accordingly, with phase leads x', y', z' groups of the windings (2), belonging to the reverse star of the first six-phase star, and phase leads x, y, z of the reverse star belonging to the second six-phase star, are connected by three unidirectional gates (13, 18, 8) which have been switched on, accordingly, with phase outputs a', b', c' of the star belonging to the first six-phase star. From the gates of the devices (12, 15, 17, 4, 7, 10) a six-valve anodic star is formed, and from the gates (14, 6, 9) a three-star cathodic star is formed, free electrodes of the gates (12, 17, 7, 4, 10, 15) are connected, accordingly, with phase leads a, b, c, x, y, z of the second six-phase star, free electrodes of gates (6, 9, 14) of three-valve stars are connected, accordingly, to the phase leads a', b', c' of the straight star belonging to the first six-phase star. All the gates of the device are included unidirectional, and the general points (19 and 20), accordingly, the six- and three-valve stars form output leads of the converter to which is connected the load (21).

EFFECT: reduction in the mass and size parameters.

3 dwg

Description

The invention relates to the field of converter technology and may find application for supplying direct current consumers.

Known AC to DC converters with a 9-fold ripple frequency (as.s. SU No. 1056398, H02M 7/12, publ. 11/23/1983; ass. SU No. 1319198, 4 H02M 7/12, publ. 23.06. 1987).

The disadvantages of these converters are the large values of the typical capacities of the transformers, which is associated with the unidirectional operation of the secondary windings.

Known AC to DC Converter with a 9-fold ripple frequency (Repin A.M. New basic technical solutions and classification of valve energy converters // Radio Electronics Issues. OVR Series, 1985. - Issue 6. - P.65-83).

The disadvantage of this converter is the relatively high value of the typical power of the transformer.

Closest to the invention adopted as a prototype is an AC to DC converter with a 9-fold ripple frequency (US Pat. RU No. 2286644, IPC Н02М 7/08, publ. 10/27/2006) containing a three-phase transformer with a primary and two groups of secondary windings interconnected according to the six-phase star scheme with a zero point, and nine gate elements, three of which are connected to the phases of the secondary windings of one of the two mentioned groups in the zero circuit, while the converter is equipped with an additional group of secondary an outflow, also connected by a star circuit, with each phase winding of another group of secondary windings through a corresponding previously unused valve element connected to the opposite phases of the secondary windings of the additional group, and a load is connected between the zero point of two groups of secondary windings and the zero point of the additional group of secondary windings.

The disadvantage of this converter is the large overall dimensions.

The objective of the invention is the creation of an AC to DC converter with a 9-fold ripple frequency, which has lower overall dimensions.

, а числа витков обмоток, образующих первую шестифазную звезду находятся в соотношении

с числами витков соответствующих обмоток второй шестифазной звезды, причем каждый фазный вывод обмоток звезды, принадлежащей второй шестифазной звезде, соединен вентилем с фазным выводом обмотки обратной звезды, расположенной на том же стержне трансформатора и принадлежащей первой шестифазной звезде, а каждый фазный вывод обмотки обратной звезды, принадлежащей второй шестифазной звезде, соединен вентилем с фазным выводом обмотки звезды, расположенной на том же стержне трансформатора и принадлежащей первой шестифазной звезде, при этом из девяти вентилей устройства сформированы шестивентильная и трехвентильная звезды, общие точки в каждой из этих звезд образованы одноименными электродами вентилей, свободные электроды вентилей шестивентильной звезды соединены с фазными выводами обмоток второй шестифазной звезды, свободные электроды вентилей трехвентильной звезды соединены с фазными выводами обмоток звезды, принадлежащей первой шестифазной звезде, все вентили преобразователя включены однонаправлено, а общие точки вентильных звезд образуют выходные выводы преобразователя.This problem is achieved by the fact that the AC to DC converter with a 9-fold ripple frequency, containing nine gates and a three-phase transformer with a group of secondary windings interconnected by a six-phase star with a zero point, and a second group of secondary windings connected by a reverse circuit star, equipped with six additional valves and an additional group of secondary windings connected according to the star scheme and forming a second six-phase star with zero t with the second group of windings chkoy, wherein the number of turns of the windings connected in a star, and the number of turns of windings connected in star feedback scheme, a six-phase two stars are in the ratio

and the number of turns of the windings forming the first six-phase star are in the ratio

with the numbers of turns of the corresponding windings of the second six-phase star, each phase output of the windings of the star belonging to the second six-phase star connected by a valve to the phase output of the winding of the reverse star located on the same transformer rod and belonging to the first six-phase star, and each phase output of the winding of the reverse star, belonging to the second six-phase star, connected by a valve to the phase output of the star winding located on the same transformer rod and belonging to the first six-phase star, while six-valve and three-valve stars are formed from nine valves of the device, common points in each of these stars are formed by the same valve electrodes, free electrodes of the six-valve star valves are connected to the phase leads of the second six-phase star windings, free electrodes of the three-valve star valves are connected to the phase leads of the star windings belonging to the first six-phase star, all the valves of the converter are turned on unidirectionally, and the common points of the valve stars form the output terminals of the of the developer.

Figure 1 shows a circuit diagram of the proposed Converter; figure 2 - vector voltage diagrams presented in the form of amplitude-phase portraits of the voltages of the phase windings, and detailed vector diagrams explaining the principle of formation of the vectors of the resulting voltages; figure 3 - diagram of the windings and valves of the Converter.

The converter contains a three-phase transformer 1 with a group of secondary windings 2 connected in a circuit forming the first six-phase star, and a group of secondary windings 3 connected in a circuit forming a second six-phase star, and fifteen valves 4 ... 18. The phase leads a, c, c of the group of windings 3 belonging to the star of the second six-phase star are connected by three unidirectionally connected valves 5, 11, 16, respectively, to the phase outputs x ', y', z 'of the group of windings 2, belonging to the reverse star of the first six-phase stars, and the phase leads x, y, z of the reciprocal star belonging to the second six-phase star are connected by three unidirectionally connected valves 13, 18, 8, respectively, with the phase leads a ', b', c 'of the star belonging to the first six-phase star. A six-valve anode star is formed from the valves of the device 12, 15, 17, 4, 7, 10, and a three-valve cathode star is formed from the valves 14, 6, 9, the free electrodes of the valves 12, 17, 7, 4, 10, 15 are connected, respectively, with the phase terminals a, b, c, x, y, z of the second six-phase star, the free electrodes of the valves 6, 9, 14 of the three-valve star are connected, respectively, with the phase terminals a ', b', c 'of a direct star belonging to the first six-phase star . All valves of the device are turned on unidirectionally, and the common points 19 and 20, respectively, of six- and three-valve stars form the output terminals of the converter, to which the load 21 is connected.

. Соотношение между числами витков соответствующих обмоток группы 2 и группы 3 равно

. При таких соотношениях обеспечивается равенство результирующих напряжений и требуемый фазовый сдвиг между ними 40 эл. град.The principle of operation of the device (Figure 1) is illustrated by vector diagrams of voltages, presented in the form of amplitude-phase portraits of the voltages of the phase windings, comprising two asymmetric six-phase voltage systems of groups of secondary windings, and by vector diagrams unfolded on the phase plane, showing the principle of formation of the resulting voltages represented by vectors S1-S9 (Figure 2). In each group of secondary windings galvanically connected among themselves, the ratio of the number of turns of phase windings making up direct stars to the numbers of turns of phase windings making up reverse stars is

. The ratio between the number of turns of the corresponding windings of group 2 and group 3 is equal to

. With these ratios, the equality of the resulting voltages and the required phase shift between them of 40 el. hail.

The formation of a 9-pulse rectified voltage at the load occurs in accordance with the vector diagrams, which are combined in FIG. 2 with the current compositions of the phase portraits of the voltage of the secondary windings. So, the first vector of the resulting voltage S1 is the sum of the vectors of the phase voltages of the secondary windings with phase terminals x, a, x 'a' located on one transformer rod. Vector S2 is a linear voltage vector obtained from the voltages of the windings with phase terminals c, z, c ', a', placed on two rods of the transformer. The transformer generates twelve identical resultant voltages forming an asymmetric 12-phase system, but only 9 resultant voltages are used, forming a symmetric 9-phase system of stresses on the load. In the diagrams of Figure 2 it is seen that the vectors located between the pairs of vectors S2-S3, S3-S6, S8-S9 are not used.

This is accomplished by using phase windings with phase terminals x ', y', z 'in unidirectional operation (with the exception of the gate connections of these phases to the cathode terminal of the converter). The remaining secondary windings of the transformer operate in bidirectional mode.

The operation diagram of the windings and valves (Fig. 3), obtained from the analysis of the diagrams in Fig. 2, allows us to determine that all the windings of the second six-phase star (winding group 3 in Fig. 1) operate on 120 el. hail., star windings (phase outputs a ', b', s') work 200 e. hail., windings of the reverse star (phase outputs x ', y', z ') - 40 e. hail. The valves of the cathode valve group 6, 9, 14 have a conductivity angle of 120 el. hail.; valves 7, 8, 12, 13, 17, 18 have a conductivity angle of 80 el. hail.; valves 4, 5, 10, 11, 15, 16 included 40 e. hail. over a period of mains voltage. The order of entry of the valves 4 ... 18 in the work is reflected in their numbering in the diagram of Figure 1.

Based on the geometric construction of the diagrams of formation of the vectors of the resulting voltages (Figure 2) determined the maximum value of the rectified voltage with perfect switching and, accordingly, its average value. Taking the amplitude of the voltage on the secondary phase winding having the largest number of turns as the relative unit (p.u.), the average value of the rectified voltage U _do = 2.481 p.u.

Based on the analysis of the windings, the power of the secondary windings was determined, amounting to 1.257 P _d . The installed power factor of the transformer of the proposed converter is 1.139, and the prototype has more - 1.5. Despite the increase in the number of valves, a significant difference in the typical capacities of transformers suggests a decrease in the overall dimensions of the proposed converter.

Thus, the proposed AC to DC converter with a 9-fold ripple frequency has lower overall dimensions.

Claims (1)

An AC to DC converter with a 9-fold ripple frequency, comprising nine gates and a three-phase transformer with a group of secondary windings interconnected according to a six-phase star with a zero point, and a second group of secondary windings connected by a reverse star, characterized in that equipped with six additional valves and an additional group of secondary windings connected according to the star pattern and forming a second six-phase star with a zero point with the second group of windings, while weakly turns of windings connected in a star, and the number of turns of windings connected in star feedback circuit, both six-phase stars, are in the ratio

, and the number of turns of the windings forming the first six-phase star are in the ratio

with the numbers of turns of the corresponding windings of the second six-phase star, each phase output of the windings of the star belonging to the second six-phase star connected by a valve to the phase output of the winding of the reverse star located on the same transformer rod and belonging to the first six-phase star, and each phase output of the winding of the reverse star, belonging to the second six-phase star, connected by a valve to the phase output of the star winding located on the same transformer rod and belonging to the first six-phase star, while six-valve and three-valve stars are formed from nine valves of the device, common points in each of these stars are formed by the same valve electrodes, free electrodes of the six-valve star valves are connected to the phase leads of the second six-phase star windings, free electrodes of the three-valve star valves are connected to the phase leads of the star windings belonging to the first six-phase star, all the valves of the converter are turned on unidirectionally, and the common points of the valve stars form the output terminals of the of the developer.

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