SU866674A1

SU866674A1 - Three-phase inverter

Info

Publication number: SU866674A1
Application number: SU752180544A
Authority: SU
Inventors: Борис Лазаревич Уан-Зо-Ли; Анатолий Евгеньевич Сурминский; Владимир Самойлович Моин
Original assignee: Предприятие П/Я М-5374
Priority date: 1975-10-13
Filing date: 1975-10-13
Publication date: 1981-09-23
Also published as: SU616700A1

Description

(54) ТРЕХФАЗНЫЙ ИНВЕРТОР(54) THREE-PHASE INVERTER

II

Изобретение относитс к электротехнике и может быть использовано в системах вторичного электропитани и электропривода дл преобразовани посто нного напр жени в трехфазное переменное напр жение посредством инверторов .The invention relates to electrical engineering and can be used in secondary power supply and electric drive systems to convert a DC voltage to a three-phase AC voltage by means of inverters.

Известны трехфазные инверторы, преобразующие посто нное напр жение в трехфазное переменное напр жение с улу 1шенной фогмой выходного линейного напр жени и содержащие три моста ключей, в диагонали которых включены формирующие автотрансформаторы DD и U3.Three-phase inverters are known that convert a constant voltage to a three-phase alternating voltage with a voltage of 1 output voltage of the output line voltage and containing three bridges of keys, in the diagonal of which are included the forming autotransformers DD and U3.

Однако при работе на группу потребителей нагрузка, инвертора может быть резко несимметричной, что вызывает необходимость введени нулевого провода в цепь нагрузки и нулевого вывода источника питани с целью симметрировани выходных фазных напр жений. Форма кривой фазного напр жени инверторов данного типа имеет значительно худший спектральный состаш, чем форма кривой линейного, напр жени .However, when working on a group of consumers, the inverter may be sharply asymmetric, which necessitates the introduction of a neutral wire into the load circuit and a zero output of the power source in order to balance the output phase voltages. The shape of the phase voltage curve of inverters of this type has a much worse spectral ratio than the shape of the linear voltage curve.

Наиболее близким к предлагаемому инвертору по поставленной задаче и техническому решению вл етс трехфазный инвертор, содержавший три преобразовательные чейки, трансформаторные обмотки которых подключены к выходным цеп м, имеющим общую точку 1з1.The closest to the proposed inverter according to the task and technical solution is a three-phase inverter containing three converter cells, the transformer windings of which are connected to output circuits having a common point 1з1.

лоlo

Недостатком вл етс то, что выходное напр жение известного инвертора содержит п тую и седьмую raiwoники , т.е. спектральный состав напр жени не обеспечивает хорошего при15 ближени его формы к синусоиде.The disadvantage is that the output voltage of the known inverter contains the fifth and seventh rains, i.e. The spectral composition of the voltage does not provide a good approximation of its shape to a sinusoid.

Це.пь изобретени - повьпиение качества выходного напр жени пут улучшени спектрального состава.The purpose of the invention is to improve the quality of the output voltage by means of improving the spectral composition.

Эта цель достигаетс тем, что в This goal is achieved by the fact that

Claims

20 in the inverter when using a power source with zero output, the transformer windings are provided with additional windings connected 3 in series and connected between the zero output of the power source and the common point. FIG. I shows a diagram; in fig. 2 - voltage diagrams. The inverter contains three converter cells - three bridges of keys 1-12. In the diagonal of bridges, autotransformers with windings 13–15 are included, whose outlet are connected to the output terminals A, B, C of the corresponding inverter phases. The taps divide winding 13-15 into two parts, the ratio of turns of which is 1: 2.73. The additional 1e windings of autotransformers 16-18 are interconnected in a consistent manner and are connected between the zero terminal of the power source O and the zero terminal for the load circuit O. The inverter works as follows. When switching transistors according to a & appropriate program between the output terminals L, B and C and the zero output of the power source, a square voltage Udd, Vgo and 1c, 0 (FIG. 2) appears with ledges in the range of angles 0-30 and 150 -180, resulting in the remagnetization of the cores of autotransformers 13-15. The voltages on autotransformers tA ts ts have the form shown in FIG. 2, and when summed, they form a triple frequency voltage V. The voltage difference is the phase voltage of the load circuit Udo, etc. As can be seen from FIG. 2, this voltage has the same appearance as the linear voltage, i.e. does not contain higher harmonics up to eleventh, has a distortion factor of 16%. At the same time, due to the zero wire connected to the output O, the load can have a large imbalance in phases without a sulphal imbalance of the phase voltages. The volume occupied by the additional windings is small, since they flow around only the current unbalance of the load, and the transformation ratio between the windings 13-15 and 16-18 is 0.0775: 1. A three-phase inverter containing three converter cells with transformer windings connected to output circuits having a common point characterized in that, in order to improve the quality of the output voltage by reducing the harmonics of the shape of the curve, when using a power source with zero output transformer The windings are provided with additional windings connected in series with and connected between the zero terminal of the power source and the said common point. Sources of information taken into account in the examination 1. US patent number 3781635, H 02 M 1/12, 1973.

2.Patent of France No. 2115401, H 02 M 7/00, 1972., FIG. four.

3. USSR author's certificate No. 511666, cl. H 02 M 7/48, 1974.

FLG./