SU797025A1

SU797025A1 - Three-phase inverter

Info

Publication number: SU797025A1
Application number: SU782691070A
Authority: SU
Inventors: Сергей Федорович Степанов
Original assignee: Саратовский политехнический институт
Priority date: 1978-12-04
Filing date: 1978-12-04
Publication date: 1981-01-15

Description

1one

Изобретение относитс к преобразовательной технике и предназначено дЛ частотного управлени асинхронным электродвигателем и дл создани источников повыиенной частоты.The invention relates to converter equipment and is intended for frequency control of an asynchronous electric motor and for generating high frequency sources.

Известен автономный инвертор, содержащий основные тиристоры, последовательно соединенные с ними в каждом плече -отсекающие вентили, диоды обратного тока, коммутирующие конденсаторы и дроссели, а также источники подзар да коммутирующих конденсаторов с токоограничивающими.сопротивлени ми 1J.A self-contained inverter is known, containing main thyristors connected in series with each arm — cut-off valves, reverse current diodes, switching capacitors and chokes, as well as sources of charging and switching capacitors with current-limiting 1J resistors.

Недостаток этого автономного инвертора - наличие трех источников подзар да коммутирующих конденсаторов и токоограничивающих сопротивлений, снижающих КПД устройства.The disadvantage of this autonomous inverter is the presence of three sources of subcharging and switching capacitors and current-limiting resistances, which reduce the efficiency of the device.

Известен.преобразователь частоты, содержащий основные тиристоры, последовательно соединенные с ними в каждом плече отсекающие вентили, диодыобратного тока, коммутирующиеконденсаторы , соединенные последовательно с дроссел ми 2.Known. Frequency converter containing the main thyristors, serially connected with them in each arm cut-off valves, reverse current diodes, switching capacitors connected in series with the throttles 2.

Недостатком этого преобразовател вл етс малое запирающее напр жение на рабочем тиристоре и большие значени напр жений на коммутирующихThe disadvantage of this converter is the low blocking voltage on the working thyristor and the high values of the voltages on the commuting

конденсаторах, которые в 1,5 и более раз превышают напр жение источника питани .capacitors, which are 1.5 or more times higher than the supply voltage.

Наиболее близким к предлагаемому вл етс инвертор, содержащий св занный со входными выводами через дроссель фильтра мост основных тиристоров , вьгооды переменного тока которого соединены с выходными выводами и через дроссели - с выводами переменного тока моста обратных диодов, причем последовательно с основными тиристорами каждого плеча моста включен диод , а между точками соединени тиристоров с диодами соответствующих плеч моста включены коммутирующие конденсаторы 3.The closest to the present invention is an inverter containing a main thyristor bridge connected to the input terminals through a filter choke, the AC alternators of which are connected to the output terminals and connected to the reverse diodes of the alternating current bridge through the chokes, and in series with the main thyristors of each arm of the bridge the diode, and between the points of connection of the thyristors with the diodes of the respective arms of the bridge, switching capacitors 3 are turned on.

Недостаток этого инвертора вл етс наличие перенапр жений на элементах схемы.The disadvantage of this inverter is the presence of overvoltages on the circuit elements.

Цель изобретени - повышение надежности за счет снижени напр жений на всех элементах схемы.The purpose of the invention is to increase reliability by reducing the stresses on all elements of the circuit.

Claims

This goal is achieved by the fact that the inverter has an additional choke, an additional thyristor and a series circuit connected in parallel to the main thyristor bridge and consists of an additional diode and a capacitor, the common point of which is connected through the series-connected additional choke and additional thyristor to the positive link input pins. The drawing shows a schematic diagram of the proposed inverter. The inverter contains a bridge of main thyristors 1-6, in each arm, which diodes 7-12 are connected in series with thyristors, a reverse diode bridge 13-18 connected by alternating current outputs through chokes 1921 to the output of the converter, two groups of switching capacitors 22 and. 23 connected to common points of connection of thyristors 1-6 and diodes 13-18 of filter throttle 24 connected to the power supply source 25; To the DC terminals of the main thyristors bridge 1-6 there is a series circuit from diode 26 and a capacitor 27, and after tigators but connected tiristo ra additional choke 28 and 29 connected at one end to the junction of diode 26 and kondensatora27 and the other - to compounds of the throttle point 24 and the power source 2, scheme works; sledutoschym- manner. As soon as the voltage on any of the switching capacitors 22 and 23 becomes equal. the voltage of the power supply source 25, the diode 26 will open and the switching capacitors 22 and 23 will be bridged by the capacitor 27, since the capacitance of the capacitor 27 is greater than the capacity of the switching capacitors 22 and -23 by 5-10 times the voltage on the capacitors exceeds only 5-10%. The transfer of the excess energy accumulated in the capacitor 27 of the power supply source 25 occurs in an immaterial mode with a six-fold frequency at time intervals, when the possibility of short circuits of throttle 24 by diode 26 and thyristor 28. In view of the fact that the variable component of the capacitor 27 voltage is a few percent, this capacitor can be electrothermal. A three-phase inverter, comprising: a main thyristor bridge connected to the input terminals through a filter choke, the alternating current leads of which are connected to the output terminals and through chokes to alternating current leads of the reverse diode bridge; and between the points of connection of the thyristors with the diodes of the respective shoulders of the bridge, switching capacitors are switched on, which is characterized by the fact that it is equipped with additional lnym inductor, a thyristor and additional serial chain bridge connected parallel to the main thyristor and consisting of a diode and an additional capacitor, the total point which is connected through the additional choke in series and an additional thyristor is connected to the junction between choke filter with a positive input terminal. Sources of information taken into account during the examination 1. USSR author's certificate number 349364, class, N 02 M 7/515, 1969.

2. Zabrodin Yu.S. Nodes of forced capacitor switching thyristors. M., Energie, 1974, p. 13.

3. Golembiovsky Yu.M. Investigation of quasi-established processes of three-throttle-1x frequency converter circuits with intermediate DC link. Author. dis. Nrvosib Irsk, 1971, p. 17