RU2510568C1 - Twelve-phase step-up autotransformer phase changer - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: device includes a three-phase autotransformer, having three windings 1, 2, 3 of a primary coil and six windings 4, 5, 6, 7, 8, 9 of secondary coils, six interconnected windings 4, 5, 6, 7, 8, 9 of a primary coil, having taps 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21 from windings, the winding 1 of the primary coil of the first phase is connected by its end to a node B, where windings 6 and 8 of the secondary coils of the second phase and third phase are connected; the winding 2 of the primary coil of the second phase is connected by its end to a node D, where the windings 9 and 5 of secondary coils of the third phase and the first phase are connected; the winding 3 of the primary coil of the third phase is connected by its end to a node F, where windings 4 and 7 of secondary coils of the first phase and the second phase are connected; the beginning of the winding 4 of the secondary coil is connected to the beginning of the winding 8 of the secondary coil to form a node A; the end of the winding 8 of the secondary coil is connected to the end of the winding 6 of the secondary coil to form a node B; the beginning of the winding 6 of the secondary coil is connected to the beginning of the winding 5 of the secondary coil to form a node C; the end of the winding 5 of the secondary coil is connected to the end of the winding 9 of the secondary coil to form a node D; the beginning of the winding 9 of the secondary coil is connected to the beginning of the winding 7 of the secondary coil to form a node E; the end of the winding 7 of the secondary coil is connected to the end of the winding 4 of the secondary coil to form a node F and close the loop of windings of the secondary coils forming a "hexagon" A, B, C, D, E, F; each winding of the secondary coil of the autotransformer is a side of the "hexagon" A, B, C, D, E, F, which converts a symmetrical three-phase voltage system to a symmetrical six-phase voltage system.

EFFECT: design of a converter which reduces consumption of active materials while replacing a three-phase transformer with an autotransformer, thereby improving weight and size characteristics of the converter and reducing material cost of its production.

2 dwg

Description

The present invention relates to a conversion technique and can be used to create rectifiers for adjustable DC and AC drives to increase machine speed, as well as in converter substations for electrified railways, in the electrometallurgical and chemical industries to reduce the ripple of the rectified voltage and to reduce the content higher harmonic components in the AC curve in the three-phase power supply hildren.

The prior art transformer converters of three-phase alternating voltage to multiphase voltage. For this, the three-phase transformer is equipped with an additional group of secondary windings. The groups of secondary windings are connected with the opposite phases of the additional secondary windings according to the zigzag circuit (V. Kazakov. Power supplies. Multiphase power transformers-converters and rectifiers. Power electronics No. 4, 2006, pp. 7-15).

The disadvantage of such devices is the large number of secondary windings, which greatly complicates the design of the converter, the technology of its manufacture, leads to cost overruns and an increase in its cost.

The closest solution in technical essence and the achieved result is a phase number converter used to obtain multiphase voltage, consisting of three single-phase transformers, each containing one primary winding and requiring several groups of secondary windings (G. Vorfolomeev et al. Overview of circuit solutions phase number converters on transformers. Improving the technical means of electric transport. Collection of scientific papers. Issue 2. Novosibirsk, 2001, p. 78-96). The phase number converter requires a three-phase network, three single-phase transformers with three primary windings connected to a three-phase network, and thirteen secondary windings that create twelve outputs of the twelve-phase voltage system for their implementation.

A disadvantage of the known device is the fact that a group three-phase transformer is inferior to a three-phase three-rod autotransformer in terms of weight and dimensions, and the converter has a large number of secondary windings with various parameters, which greatly complicates the design of the converter, its manufacturing technology and leads to cost overruns and an increase in its cost .

The technical result of the invention is the creation of such a converter architecture that will reduce the consumption of active materials when replacing a three-phase transformer with an autotransformer, thereby improving the overall dimensions of the converter and reducing material costs for its manufacture.

The technical result is achieved due to the fact that in a twelve-phase step-up autotransformer, the number of phases, which is a three-phase autotransformer, consisting of three primary winding coils connected to a three-phase network, and six secondary winding coils connected by nodes in a hexagon pattern, with twelve outputs of a symmetrical twelve-phase voltage, according to the invention, each primary coil is connected at its beginning to one of the phases of the network, and the end to the node hexagon in such a way that each of the nodes is a set of three coils, one primary coil and two secondary coils located on different rods of the magnetic circuit belonging to different phases.

The invention is illustrated by graphic materials, where:

- figure 1 presents a diagram of a twelve-phase autotransformer converter of the number of phases with an increased phase voltage at the output of the converter compared to the phase voltage at the input of the autotransformer;

- figure 2 shows a vector diagram of potentials on the secondary windings of this Converter.

The twelve-phase step-up autotransformer phase converter consists of a three-phase autotransformer having three coils 1, 2 and 3 of the primary winding and six coils 4, 5, 6, 7, 8 and 9 of the secondary windings. Six interconnected coils 4, 5, 6, 7, 8, 9 of the secondary winding have soldering 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21 from the turns. The coil 1 of the primary winding of the first phase is connected at its end to the assembly B, in which the coils 6 and 8 of the secondary windings of the second phase and third phase are connected. The coil 2 of the primary winding of the second phase is connected at its end to the node D, in which the coils 9 and 5 of the secondary windings of the third phase and the first phase are connected. The coil 3 of the primary winding of the third phase is connected at its end to the node F, in which the coils 4 and 7 of the secondary windings of the first phase and the second phase are connected. The beginning of the secondary coil 4 is connected to the beginning of the secondary coil 8, forming a node A, the end of the secondary coil 8 is connected to the end of the secondary coil 6, forming a node B, the beginning of the secondary coil 6 is connected to the beginning of the secondary coil 5, forming a node C , the end of the secondary coil 5 is connected to the end of the secondary coil 9, forming a node D, the beginning of the secondary coil 9 is connected to the beginning of the secondary coil 7, forming a node E, the end of the secondary coil 7 is connected to the end of the coil 4 secondary winding, forming a node F, and closing the contour of the coils of the secondary windings forming a "hexagon" A, B, C, D, E, F. Each coil of the secondary winding of the autotransformer is a side of the "hexagon" A, B, C, D, E, F, transforming a symmetric three-phase voltage system into a symmetric six-phase voltage system. The voltage of the twelve-phase voltage system depends on the voltage of the six-phase system and is connected with it by the ratio: U ₁₂ = U ₆ Cos30 ° / Cos15 ° = 0.897U ₆ , which follows from the consideration of rectangular triangles (0-С-22) and (0-е- 22): (0-22) = U ₆ Cos30 ° = U ₁₂ Cos15 °, where 15 ° = 30 °: 2.

Now we will determine the position of the taps 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21 from the turns of the coils 4, 5, 6, 7, 8, 9 of the secondary windings using the example of coil 5. For this we use the vector diagram (figure 2), taking the number of turns of the coil 5 proportional to the length of the voltage vector on the coil 5. We take the length of the voltage vector in the phase of the six-phase polygon per unit. Solderings 12 and 13 from the turns of the coil 5 divide its number of turns in a ratio determined by the ratio of the segments (C-e), (ef) and (fD). Segment (C-e) = (fD) = U ₆ Sin30 ° -U ₁₂ Sin15 °. Expressing U ₁₂ through U ₆ after transformations, we obtain: (C-е) = 0.5U ₆ (1-Tg60 ° Tg15 °) and the following ratio of the numbers of turns from which the soldering is performed: (0.5-Tg60 ° Tg15 °) : (Tg60 ° Tg15 °) :( 0.5-Tg60 ° Tg15 °) = 0.268: 0.464: 0.268.

The work of the twelve-phase boost autotransformer of the number of phases is as follows.

When a three-phase autotransformer is connected to a three-phase network, three magnetic fluxes appear in the terminals of the autotransformer magnetic circuit, phase shifted relative to each other by a third of the period or in degree measurement by 120 °. The implementation of the secondary winding for each phase in the form of two coils on the rod of each phase allows you to get two secondary voltage with opposite polarity (with a shift of 180 °). Thus, with three mains voltages phase-shifted by 120 °, six secondary voltages are obtained, phase-shifted relative to each other by 60 °. When connecting six coils 4, 5, 6, 7, 8, 9 of the secondary windings as described above, we obtain a hexagon A, B, C, D, E, F with a symmetric six-phase voltage system on coils 4, 5, 6, 7 , 8, 9 of the secondary winding.

The analysis showed that on the turns of the coils 4, 5, 6, 7, 8, 9 of the secondary winding, forming the hexagon A, B, C, D, E, F, you can find twelve points a, b, c, d, e, f, g, h, k, l, m, n, whose potentials are equal in magnitude, but differ in phase by one twelfth of the period, which is 30 ° in degree measurement, and get a twelve-phase symmetrical system of voltages a, b, c, d, e, f, g, h, k, l, m, n.

As an example, consider an autotransformer converter with a phase voltage value of a twelve-phase system equal to the phase voltage value of the supply network converter: U ₁₂ = U _c .

To obtain such a voltage, the autotransformer must be step-up, the circuit of which is presented in figure 1. The number of turns of the primary winding coil can be represented by the length of the leg (B-1) of the right triangle (B-1-c) in the vector diagram in figure 2 and can be determined through the leg (1-c): (B-1) = ( 1-c) tg30 °, a (1-c) from the triangle (0-1-s) we get: (1-s) = U ₁₂ Sin15 ° = U _c Sin15 °.

In the transformer version of the converter, the number of turns of the primary winding will be proportional to the value of U _c at the same current in the winding. Therefore, in the considered autotransformer variant, the number of turns of the primary winding coil decreases by 1 / Sin15 ° times, i.e. 1 / 0.2588 = 3.864 times.

At U _c = U _{6, the} primary winding coils are not required and the vertices of the hexagon B, D and F are connected to the network phases 1, 2, and 3. At U _c <U _{6, a} boost autotransformer is taken. It is generally accepted that with a transformation coefficient k = U _c / U ₆ lying within 0.5 <k <1, if an electrical connection between the primary and secondary circuits is acceptable, an autotransformer is preferable to a transformer.

Thus, the claimed combination of essential features set forth in the claims allows to reduce the consumption of active materials when replacing a three-phase transformer with an autotransformer. As a result, the overall dimensions of the converter are improved and its cost is reduced.

The analysis of the claimed technical solution for compliance with the requirements of patentability showed that the characteristics indicated in the independent claim are interrelated with each other with the formation of a stable set of necessary features, unknown at the priority date from the prior art, sufficient to obtain the required synergistic (over-total) technical result.

The properties regulated in the claimed are connected by separate features, are well known from the prior art and do not require additional explanation.

Thus, the above information indicates the fulfillment of the following set of conditions when using the claimed technical solution:

- the object embodying the claimed technical solution, in its implementation is intended for use in the creation of adjustable DC electric drives;

- for the claimed object in the form described in the independent claim, the possibility of its implementation using the means and methods known from the prior art on the priority date on the priority date has been confirmed;

- the object embodying the claimed technical solution, when implemented, is able to ensure the achievement of the technical result perceived by the applicant.

Therefore, the claimed subject matter meets the requirements of patentability “novelty”, “inventive step” and “industrial applicability” under applicable law.

Claims (1)

A twelve-phase step-up autotransformer phase converter, which is a three-phase autotransformer, consisting of three primary winding coils connected to a three-phase network, and six secondary winding coils connected by nodes in a hexagon pattern, with twelve outputs of a symmetric twelve-phase voltage, characterized in that each primary coil the winding is connected at its beginning to one of the phases of the network, and the end to the hexagon node in such a way that each node represents second set of three coils, one coil of the primary winding and the secondary windings of the two coils located on different cores of magnetic circuits belonging to different phases.

Images