SU714599A1

SU714599A1 - Self-sustained serial inverter

Info

Publication number: SU714599A1
Application number: SU782604631A
Authority: SU
Inventors: Виктор Васильевич Шипицын; Валентина Николаевна Антонова; Владислав Игоревич Лузгин; Андрей Александрович Рухман; Алексей Алексеевич Новиков; Виктор Владимирович Рудный
Original assignee: Уральский ордена Трудового Красного Знамени политехнический институт им. С.М.Кирова
Priority date: 1978-04-12
Filing date: 1978-04-12
Publication date: 1980-02-05

Description

Изобретение относится к преобразовательной технике и может быть использовано в качестве источника питания для электротермических установок.The invention relates to a conversion technique and can be used as a power source for electrothermal installations.

Известен ряд схем последовательных инверторов, в которых для расширения $ нагрузочного диапазона используются дополнительные контуры, осуществляющие возврат избыточной реактивной энергии, запасенной в электромагнитных полях элементов схемы, в источйик питания.A number of series inverter circuits are known in which additional circuits are used to expand the $ load range, which return excess reactive energy stored in the electromagnetic fields of the circuit elements to a power source.

Известна схема независимого инвертора [1] , в которой ограничение степени раскачки напряжении на реактивных элементу и силовых вентилях в режимах,₍₅близких к короткому замыканию, осуществляется за счет введения ветрейно— параллельных неуправляемых вентилей. Такой способ ограничения не позволяет получить рабочие частоты выше 2,5 кГц, 20 так как обратное напряжение, прикладываемое к управляемым вентилям, определяется малой величиной падеш я напряжения на работающих встречно—параллель2 ных вентилях. Последнее обстоятельство требует увеличения времени, необходимого для восстановления управляемости силовых вентилей, а следовательно, приводит к сужению частотного диапазона.There is a known independent inverter circuit [1], in which the degree of voltage buildup on the reactive element and power valves in the modes ₍₅ close to short circuit) is limited by introducing wind-parallel uncontrolled valves. This limitation method does not allow to obtain operating frequencies above 2 , 5 kHz, 20 since the reverse voltage applied to the controlled valves is determined by the small voltage drop across the operating counter-parallel valves. the time required to restore the controllability of the power valves, and therefore leads to a narrowing of the frequency range.

Наиболее близкой является схема инвертора [2] , содержащая связанные с входными выводами через дроссели фильтра тиристорный мост с коммутирующим конденсатором в диагонали переменного тока и две последовательные цепочки, состоящие каждая из конденсатора и дросселя, между общими точками которых включен диод.The closest is the inverter circuit [2], containing a thyristor bridge with a switching capacitor in the diagonal of an alternating current connected to the input terminals through the filter inductors and two consecutive chains, each consisting of a capacitor and a reactor, between which common points the diode is connected.

Существенным преимуществом данной схемы перед приведенной выше является создание более благоприятных условий для работы вентилей. Это, прежде всего, заключается в значительном снижении скорости нарастания прямого напряжения, прикладываемого к тиристорами, и времени, предоставляемого для восстановления управляемости тиристоров, к которым в выключенном состоянии прикладываетсяA significant advantage of this scheme over the above is the creation of more favorable conditions for the operation of valves. This, first of all, consists in a significant decrease in the slew rate of the forward voltage applied to the thyristors, and the time allowed to restore the controllability of the thyristors, which are applied in the off state

I · 7145.99 4.I 7145.99 4.

.... значительное отрицательное напряжение, что позволяет получить более высокие частоты..... significant negative voltage, which allows higher frequencies to be obtained.

К недостаткам рассматриваемой схемы относится низкий КПД инвертора 5 за счет малой амплитуды первой гармоники тока, протекающего через нагрузку, С полью повышения КПД и надежности инвертора в работе за счет обеспечения устойчивой его работы при изменении *¹⁰нагрузки, в предлагаемом инверторе дроссель одной из последовательных цепочек выполнен с отводом и соединен последовательно с цепью нагрузки, причем их точка соединения связана с упомянутой ¹⁵общей точкой другой цепочки через дополнительный диод, а между отводом дросселя и анодной группой моста включен вспомогательный диод.The disadvantages of the considered circuit include the low efficiency of the inverter 5 due to the small amplitude of the first harmonic of the current flowing through the load, in order to increase the efficiency and reliability of the inverter in operation by ensuring its stable operation when the load changes * ¹⁰ , the throttle of one of the series circuits in the proposed inverter made with a tap and connected in series with the load circuit, and their connection point is connected to the aforementioned ¹⁵ common point of another chain through an additional diode, and between the tap of the inductor and the anode g A bridge diode is turned on by an auxiliary bridge.

Схема инвертора представлена на ²⁰ чертеже. Инвертор содержит мост тиристоров 1-4, в диагональ переменного тока Которого включен коммутирующий конденсатор 5, дроссели фильтра 6, 7 и две последовательные цепочки, одна из которых²⁵состоит из конденсаторам (разделительного) 8, дросселя (коммутирующего) 9 и нагрузки 10, а другая — из дросселя 11 и конденсатора 12^ общая точка конденсатора 8 и дросселя 9 через диод 13 ³⁰и точка соединения дросселя 9 инагрузки 10 через дополнительный диод 14 соединены с обшей точкой дросселя 11 и конденсатора 12, а отвод дросселя 8 соединен через вспомогател ьный диод 15.. ³⁵Схема инвертора работает следующим образом. дThe inverter circuit is shown in ²⁰ drawing. The inverter contains a thyristor bridge 1-4, in the diagonal of the alternating current of which a switching capacitor 5 is included, filter chokes 6, 7 and two series circuits, one of which ²⁵ consists of capacitors (isolation) 8, inductor (switching) 9 and load 10, and the other is from the inductor 11 and the capacitor 12 ^ the common point of the capacitor 8 and the inductor 9 through the diode 13 ³⁰ and the connection point of the inductor 9 of the load 10 through an additional diode 14 are connected to the common point of the inductor 11 and the capacitor 12, and the outlet of the inductor 8 is connected through an auxiliary diode fifteen.. ³⁵ The inverter circuit operates as follows. d

Полный цикл работы схемы определяется частотой управления типисторами 1-4. Каждый такт характеризуется рабочим и нерабочим состоянием вентильного моста, т.е. наличием и отсутствием тока коммутирующего’ контура. В течение такта работа схемы разбивается на четыре . интервала.The full cycle of the circuit is determined by the frequency of control typistorov 1-4. Each cycle is characterized by the working and inoperative state of the valve bridge, i.e. the presence and absence of current switching ’circuit. During the cycle, the operation of the circuit is divided into four. interval.

X интервал. При отпирании тиристоров 1, 4 по контуру 5-4-10-9-15-1-5 протекает импульс тока перезаряда ком- . мутирующего конденсатора 5. При’этом через нагрузку 10 ток протекает снизу вверх. В момент равенства напряжений части коммутирующего дросселя 9 и коммутирующего конденсатора 5 диод 15 закрывается. _д5 X interval. When unlocking thyristors 1, 4 along the circuit 5-4-10-9-15-1-5, a pulse of recharge current com- mutating capacitor 5. In this case, through the load 10, the current flows from the bottom up. At the moment of equal voltage part of the switching inductor 9 and the switching capacitor 5, the diode 15 is closed. _d5

П интервал. Ток перезаряда коммутирующего конденсатора 5 замыкается по цепи 8-L-5-4-10-9-8. Через нагруэ.........ку ток протекает снизу вверх, В момент перехода тока коммутирующего контура через амплитудное значение напряжения на коммутирующем дросселе меняет полярность. Как только напряжение на этом дросселе по величине превысит сумму напряжения источника питания и падение напряжения на нагрузке, открывается диод 13. Ток в цепи коммутирую· щего контура резко спадает до нуля.P interval. The overcharge current of the switching capacitor 5 is closed on the circuit 8-L-5-4-10-9-8. Through the load ......... ku, the current flows from the bottom up. At the moment the current of the switching circuit passes through the amplitude value of the voltage at the switching reactor, it changes polarity. As soon as the voltage across this inductor exceeds the sum of the voltage of the power source and the voltage drop across the load, diode 13 opens. The current in the circuit of the switching circuit drops sharply to zero.

Ш интервал. Избыток реактивной энергии, запасенной в электромагнитном поле коммутирующего дросселя, рассеивается на конденсаторе 12 и нагрузкеW interval. The excess reactive energy stored in the electromagnetic field of the switching inductor is dissipated on the capacitor 12 and the load

10. Ток сброса протекаетjпо контуру10. The discharge current flows along the circuit

9—13—12—10—9. Ток через нагрузку протекает сйизу вверх. ,9-13-12-10-9. Current through the load flows upward. ,

W интервал характеризуется бестоковой паузой схемы инвертора, которая длится до включения тиристоров 2, 3. Ври этом ток заряда конденсатора 8 обеспечивает протекание токА через нагрузку сверху вниз. Первый такт работы схемы закончен.The W interval is characterized by a currentless pause of the inverter circuit, which lasts until the thyristors 2, 3 are turned on. At the same time, the charge current of the capacitor 8 ensures that the current flows through the load from top to bottom. The first cycle of the circuit is finished.

Процессы, происходящие во втором такте, , аналогичны описанным выше, по окончании второго такта включаются ти- \ ристоры 1, 4, и цикл работы схемы инвертора повторяется.The processes occurring in the second cycle are similar to those described above, at the end of the second cycle, thyristors 1, 4 are turned on, and the cycle of the inverter circuit is repeated.

В данной схеме инвертора помимо ограничения напряжений на тиристорах и реактивных элементах предусмотрено ограничение напряжения на нагрузке 10 до величины питающего напряжения с помощью диода 14, что обеспечивает . устойчивую работу инвертора при изменении нагрузки в широких пределах.In this inverter circuit, in addition to limiting the voltages on the thyristors and reactive elements, it is provided that the voltage at load 10 is limited to the value of the supply voltage using diode 14, which provides. stable operation of the inverter when the load changes over a wide range.

Таким образом, предлагаемый последовательный инвертор позволяет повысить КПД за счет улучшенного Гармонического состава нагрузки на 10-15% и обеспечивает устойчивую работу на резко переменную нагрузку.Thus, the proposed serial inverter allows you to increase the efficiency due to the improved Harmonic composition of the load by 10-15% and ensures stable operation on a sharply variable load.

Claims

The invention is relative; to convert the technique of technology and be used as a power source for electrothermal installations. Known for a series of successive schemes. SE inverts, which use additional hollow circuits to expand the load range, performed the return of the excess reactive energy stored in the electromagnetic fields of the circuit elements to the power supply. A known circuit is an independent inverter 1 in which limiting the degree of buildup of the voltage on the reactive element and the power valves in the mode close to short. the closure is accomplished by the introduction of mutually parallel unmanaged gates. Such a limiting method does not allow to obtain operating frequencies above 2.5 kHz, which, like the reverse voltage applied to controllable valves, is determined by the small value of the drop on the running anti-parallel gates. The latter circumstance requires an increase in the time required to restore the controllability of the power valves, and, consequently, leads to a narrowing of the frequency range. The closest is the inverter circuit 2, which contains a thyristor bridge with a switching capacitor in the alternating current diagonal connected to the input pins via filter chokes and two successive circuits, each consisting of a capacitor and a throttle, between which common points a diode is connected. A significant advantage of this scheme over the above is the creation of more favorable conditions for the operation of the valves. This primarily means a significant reduction in the rate of rise of the direct voltage applied to the thyristors, and the time allowed to restore the controllability of the thyristors, to which the 1HDH-iTo1HY1Oe negative voltage is applied in the off state, which will get more In the frequency range. The disadvantages of this scheme are the low efficiency of the inverter due to the small amplitude of the first harmonic of the current flowing through the load. In order to increase the efficiency and reliability of the inverter by ensuring stable operation when the load changes, the proposed inverter is one of the successive circuits made with a tap and connected in series with the load circuit, and their junction point is connected to the common point of another chain through an additional diode, and between the pull socket and the anode group The bridge is connected to the auxiliary diode. The inverter circuit is shown in the drawing. The inverter contains a thyristor bridge 1-4, in the diagonal of the alternating current of which the switching capacitor 5 is connected, the filter chokes 6, 7 and two successive chains, one of which consists of a capacitor (separation) 8, chokes (switching) 9 and load 10, and another - from drossel 11 and condenser 12, the common point of capacitor 8 and throttle 9 through diode 13 and the junction point of throttle 9 and load 10 through additional Dyod 14 are connected to common throttle point. Ii and the capacitor 12, and the outlet of the chokesel 8 is connected via an auxiliary diode 15, the inverter circuit works as follows. The full cycle of the circuit operation is determined by the thyristor control frequency 1-4. Each clock cycle is characterized by the operating and non-operating state of the valve, i.e. . the presence and absence of the current switching circuit. During the clock cycle, the operation of the circuit is divided into four intervals. X interval When the thyristors 1, 4 are unlocked along the circuit 5-4-10-9-15-1-5, a current pulse recharges the switching capacitor 5. A current flows through the load 1O from the bottom up. At the moment of the equality of the voltages of the part of the switching throttle 9 and the commutation of the dummy capacitor 5, the diode 15 is closed. YY interval. The restart current of the switching capacitor 5 is closed along the circuit 8-1-5-4-10-9-8. Through the load current flows from the bottom up. At the moment when the current of the switching circuit passes through the amplitude value of the voltage on the switching choke, the polarity changes. As soon as the voltage across this choke exceeds the sum of the voltage of the power source and the voltage drops across the load, diode 13 opens. The current in the circuit of the switching circuit drops sharply to zero. W interval. An excess of reactive energy stored in the electromagnetic field of the commutating throttle is dissipated by the capacitor 12 and the load 10. The discharge current flows along the circuit 9-13-12-10-9. The current through the load flows upwards. The IV interval is characterized by a non-current pause of the inverter circuit, which lasts until the switching on of the thyristors 2, 3. In this case, the charge current of the capacitor 8 allows current to flow through the load from top to bottom. The first cycle of the circuit is over. The processes occurring in the second cycle are similar to those described above, at the end of the second cycle the thyristors 1, 4 are turned on, and the cycle of operation of the inverter circuit is repeated. In this inverter circuit, in addition to limiting the voltages on the thyristors and reactive elements, it is possible to limit the voltage on the 1O load to the value of the supply voltage through the diode 14, which provides. stable operation of the inverter when the load changes within wide limits. Thus, the proposed serial inverter allows to increase the efficiency due to the improved harmonic composition of the load by 10–15% and ensures stable operation at a sharply variable load. Claims of a Serial Autonomous Inverter, containing a thyristor bridge connected to the input terminals through a filter chokes in an alternating current diagonal bridge and two successive chains, each chain consisting of a capacitor and Drossel, i so that, in order to improve efficiency and reliability, the throttle 57 is one of the consecutive errors with a tap and connected in series with the load circuit, and their point the connections are connected to the mentioned common point of the other chain through an additional diode, and an auxiliary diode is connected between the tap and the anode group of the bridge. Sources of information taken into account in the examination of 1. Authors certificate M 235177. class H 02 M 7/48, 1967.

2. Thyristor frequency converters for induction heating of metals, Memshoz Scientific Journal, No. 6, Ufa, 1976, p. 9, fig. one.