SU782082A1

SU782082A1 - Transistorized converter with current feedback

Info

Publication number: SU782082A1
Application number: SU792727201A
Authority: SU
Inventors: Адриан Борисович Апаров; Александр Иванович Соколов; Михаил Александрович Шумов; Александр Васильевич Старинец; Леонид Иванович Хохлов
Original assignee: Московский Ордена Ленина Энергетический Институт
Priority date: 1979-02-26
Filing date: 1979-02-26
Publication date: 1980-11-23

Description

Изобретение относится к преобразовательной технике и может быть использовано в системах вторичного электропитания и особенно эффективно при низковольтных первичных источниках питания типа радиоизотопных термоэлектрических генераторов.The invention relates to a conversion technique and can be used in secondary power supply systems and is particularly effective for low-voltage primary power sources such as radioisotope thermoelectric generators.

Известны транзисторные конверторы, содержащие два транзистора и трансформатор, имеющие повышенный КПД за счет использования токовой обратной связи [1].Known transistor converters containing two transistors and a transformer having increased efficiency due to the use of current feedback [1].

Известны также подобные конверторы, в которых вторичная обмотка трансформа-' ю тора соединена с базами транзисторов через диоды [2].Similar converters are also known in which the secondary winding of the transformer is connected to the bases of transistors through diodes [2].

Недостатком данных схем являются увеличенные значения напряжений на переходах закрытых транзисторов, что увеличивает потери в них и снижает надежность конвертора.The disadvantage of these circuits is the increased voltage values at the junctions of closed transistors, which increases the losses in them and reduces the reliability of the converter.

-Цель изобретения — повышение КПД и надежности.-The purpose of the invention is to increase efficiency and reliability.

Эта цель достигается тем, что в транзисторном конверторе с токовой обратной связью, выполненном по дифференциальной схеме, содержащем трансформатор, в цепь первичных полуобмоток которого включены силовые цепи транзисторов, база каж2 дого из которых соединена через диод с одним из концов вторичной обмотки трансформатора, а один из входных выводов соединен с одним из выходных выводов, два диода и два резистора, причем каждый из диодов включен параллельно управляющему в-оду одного из транзисторов, а каждый из резисторов включен между базой одного из транзисторов и соответствующим концом вторичной обмотки трансформатора.This goal is achieved by the fact that in a transistor converter with current feedback, made according to a differential circuit containing a transformer, the primary semi-winding circuit of which includes power transistor circuits, the base of each of which is connected through a diode to one of the ends of the secondary winding of the transformer, and one of the input terminals connected to one of the output terminals, two diodes and two resistors, each of the diodes connected in parallel to the control one of one of the transistors, and each of the resistors connected between the base -stand of the transistors and the corresponding end of the secondary winding of the transformer.

Схема предлагаемого конвертора в случае использования транзисторов типа п-р-п показана на чертеже.The circuit of the proposed Converter in the case of using transistors of the type pp-p is shown in the drawing.

Конвертор содержит трансформатор 1 с двумя обмотками первичной 2 и вторичной 3. Средняя точка первичной обмотки 2 соединена с“плюсом источника 4 питания, ¹⁵ концы ее с коллекторами транзисторов 5 и 6, эмиттеры которых соединены с минусом источника 4. Концы вторичной обмотки 3 трансформатора 1 соединены с катодами диодов 7 и 8, общая точка анодов которых 20 через нагрузку 9 соединена с плюсом источника 4 питания. Между концами вторичной обмотки 3 трансформатора 1 и минусом источника 4 питания включены две цепочки из двух встречно-последовательно включен782082 ных диодов ΊΟ—13, общая точка катодов каждой из которых подключена к базам транзисторов 5 и 6. Между концами вторичной обмотки 3 трансформатора 1 и базами транзисторов 5 и 6 включены высокоомные шунтирующие резисторы 14 и 15. _sСхема работает следующим образом. При открытом (насыщенном) транзисторе 5 напряжение источника 4 питания прикладывается к первичной обмотке 2 Трансформатора 1. Полярность вторичной обмотки 3 такова, что транзистор 5 поддер- ю живается в открытом, а транзистор 6 в закрытом состоянии. Ток нагрузки 9, являющийся током базы Открытого транзистора 5, замыкается по следующему контуру: нагрузка 9, диод 8, вторичная обмотка. 3, диод 10, переход эмиттер—база транзистора 5, источник 4 питания.The converter contains a transformer 1 with two windings of primary 2 and secondary 3. The middle point of primary winding 2 is connected to the “plus of power supply 4, ¹⁵ ends of it with collectors of transistors 5 and 6, emitters of which are connected to the minus of source 4. Ends of secondary winding 3 of transformer 1 connected to the cathodes of diodes 7 and 8, the common point of the anodes of which 20 through the load 9 is connected to the plus of the power supply 4. Between the ends of the secondary winding 3 of transformer 1 and the minus of the power supply 4, two chains of two counter-connected 782082 diodes ΊΟ-13 are connected, the common point of the cathodes of each of which is connected to the bases of transistors 5 and 6. Between the ends of the secondary winding 3 of transformer 1 and the bases transistors 5 and 6 included high-resistance shunt resistors 14 and 15. _s The circuit operates as follows. With the transistor 5 open (saturated), the voltage of the power supply 4 is applied to the primary winding 2 of the Transformer 1. The polarity of the secondary winding 3 is such that the transistor 5 is kept open and the transistor 6 is closed. The load current 9, which is the base current of the Open transistor 5, closes along the following circuit: load 9, diode 8, secondary winding. 3, diode 10, emitter-transistor base 5, power supply 4.

Диод 13 открывается током, замыкающимся по контуру: диод 13 высокоомный резистор 15, вторичная обмотка 3, диод 10, переход эмиттер—база открытого транзис- зо тора 5. При этом транзистор 6 заперт прямым падением напряжения на диоде 13.The diode 13 is opened by a current that closes along the circuit: diode 13 high-resistance resistor 15, secondary winding 3, diode 10, emitter-base of the open transistor 5. The transistor 6 is locked by a direct voltage drop across diode 13.

Под действием напряжения источника 4 питания перемагничивается магнитопровод трансформатора 1. В момент насыщения магнитопровода резко возрастает намагничивающий ток трансформатора 1, а, следовательно, и коллекторный ток транзистора 5. Падение напряжения на транзисторе 5 увеличивается, а напряжение на вторичной обмотке 3 уменьшается. Последнее приводит к уменьшению базового тока транзистора 5. Транзистор 5 выходит из насыщения, его коллекторный ток начинает уменьшаться. Напряжения на обмотках трансформатора меняют знак. Транзистор 5 закрывается, открывается транзистор 6. Далее все процессы в схеме повторяются.Under the action of the voltage of the power supply 4, the magnetic core of the transformer 1 is magnetized. At the time of saturation of the magnetic circuit, the magnetizing current of the transformer 1 increases sharply, and, consequently, the collector current of the transistor 5. The voltage drop across the transistor 5 increases, and the voltage on the secondary winding 3 decreases. The latter leads to a decrease in the base current of transistor 5. Transistor 5 goes out of saturation, its collector current begins to decrease. The voltages on the transformer windings change sign. The transistor 5 closes, the transistor 6 opens. Then all the processes in the circuit are repeated.

Из работы схемы видно, что напряжение на переходе эмиттер—база закрытого транзистора в схеме не зависит от выходного напряжения и не превышает падение напряжения на открытом диоде (0,5В).It can be seen from the circuit that the voltage at the emitter-base junction of the closed transistor in the circuit does not depend on the output voltage and does not exceed the voltage drop across the open diode (0.5V).

Резисторы 14 и 15 необходимы для задания тока через диоды 11 и 13, компенсирующего тепловой ток транзисторов 5 и 6, что обеспечивает надежное запирание транзисторов.Resistors 14 and 15 are necessary for setting the current through diodes 11 and 13, which compensates for the thermal current of transistors 5 and 6, which ensures reliable locking of the transistors.

Уменьшение напряжения на переходах закрытых транзисторов снижает рассеиваемую в них мощность, т. е. повышает КПД и надежность конвертора.Reducing the voltage at the junctions of closed transistors reduces the power dissipated in them, that is, it increases the efficiency and reliability of the converter.

Claims

The invention relates to converter technology and can be used in secondary power supply systems and is particularly effective with low-voltage primary power sources such as radioisotope thermoelectric generators. Transistor converters are known which contain two transistors and a transformer that have increased efficiency due to the use of current feedback 1. Similar converters are also known in which the secondary winding of the transformer is connected to the bases of the transistors through diodes 2. The disadvantage of these circuits is increased voltages transitions of closed transistors, which increases losses in them and reduces the reliability of the converter. Invention - increased efficiency and reliability. This goal is achieved by the fact that in a transistor KOfiBepTOpe with a current feedback made according to a differential circuit containing a transformer, the primary semi-winding circuit of which includes power circuits of transistors, the base of each of which is connected through a diode to one of the ends of the secondary winding of the transformer, and one from the input pins connected to one of the output pins, two diodes and two resistors, each diode being connected in parallel to the control of one of the transistors, and each of the resistors being connected between the base of one from transistors and the corresponding end of the secondary winding of the transformer. The circuit of the proposed converter in the case of using pn-type transistors is shown in the drawing. The converter contains a transformer 1 with two windings of primary 2 and secondary 3. The middle point of primary winding 2 is connected to the power source 4, its ends with collectors of transistors 5 and 6, the emitters of which are connected to the minus of source 4. The ends of the secondary winding 3 of transformer 1 are connected to By the cathodes of diodes 7 and 8, the common point of the anodes of which through the load 9 is connected to the plus of the power supply 4. Between the ends of the secondary winding 3 of the transformer 1 and the minus of the power source 4 there are two chains of two counter-connected diodes ip-13, the common point of the cathodes each of which is connected to the bases of transistors 5 and 6. Between the ends of the secondary winding 3 of transformer 1 and bases of transistors 5 and 6, high-resistance shunt resistors 14 and 15 are included. The circuit operates as follows. With an open (saturated) transistor 5, the voltage of the power source 4 is applied to the primary winding 2 of the transformer 1. The polarity of the secondary winding 3 is such that the transistor 5 is kept open and the transistor 6 is closed. The load current 9, which is the base current of the open transistor 5, is closed along the following circuit: load 9, diode 8, secondary winding, 3, diode 10, emitter-base junction of transistor 5, power supply 4. Diode 13 is opened by a current that closes the loop: diode 13 is a high-resistance resistor 15, secondary winding 3, diode 10, and an emitter-base junction of an open transistor 5. At the same time, transistor 6 is locked with a direct voltage drop across the diode. 13. Under the action of the voltage of the power supply source 4, the magnetic core of the transformer 1 is re-magnetized. At the moment of saturation of the magnetic circuit, the magnetizing current of the transformer 1 rises sharply, and, consequently, the collector current of the transistor 5. The voltage drop across the transistor 5 increases and the voltage on the secondary winding 3 decreases. The latter leads to a decrease in the base current of the transistor 5. Transistor 5 goes out of saturation, its collector current begins to decrease. Voltages on the transformer windings change sign. The transistor 5 is closed, the transistor 6 is opened. Next, all the processes in the circuit are repeated. It can be seen from the circuit operation that the voltage at the emitter-base junction of the closed transistor in the circuit does not depend on the output voltage and does not exceed the voltage drop on the open diode (0.5V). Resistors 14 and 15 are needed to set the current through diodes 11 and 13, which compensate for the thermal current of transistors 5 and 6, which ensures reliable locking of the transistors. Reducing the voltage at the transitions of closed transistors reduces the power dissipated in them, i.e., increases the efficiency and reliability of the converter. Claims of the transistor converter with a current feedback, made in a differential circuit, containing a transformer, in the primary semi-winding circuit of which power circuits of transistors are connected, the base of each of which is connected via a diode from one of the ends of the secondary winding of the transformer, and one of the input terminals is connected with one of the output pins, characterized in that, in order to increase reliability and efficiency, it is equipped with two diodes and two resistors, and each of the diodes is connected in parallel to the control input one of the transistors, and each of the resistors connected between the base of one of the transistors and sootvetstvuyugdim END transformer secondary winding. Sources of information taken into account in the examination 1. US patent number 3348119, cl. 321-2, 1977.

2. US patent number 4016475, i cl. 321-2, 1978. r

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