SU1372562A1 - Voltage converter - Google Patents

Abstract

The invention relates to converter equipment and can be used in sources of secondary power supply of electronic equipment. The goal is to increase reliability by eliminating the unilateral installation of a power transformer. The voltage converter contains two power transistors connected to a power transformer with primary power windings, base and output windings. The power transistor inputs are shunted by two control transistors connected to a control signal source and a pulse distributor. The use of a pulse distributor and triggering transistors ensures that the core is always reversal in the required direction. 4 il. w w

Description

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The invention relates to electrical engineering and can be used in secondary power supply and electric drive systems to convert DC voltage to AC.

The purpose of the invention is to increase reliability by eliminating the unilateral saturation of a power transformer.

Figure 1 shows a circuit diagram of a converter; Fig. 2 is a voltage converter operation diagram; figs - 4 - schemes of the pulse distributor and the generator of control pulses, respectively

The voltage converter (Fig. 1) contains power transistors 1 and 2, a power transformer 3 with primary windings 4 and 5, base windings 6 and 7 and an output winding 8, two control transistors 9 and 10, a generator 11 control pulses, a distributor 12 pulses and triggering transistors 13 and 14. The removal from the midpoint of the primary winding is connected to the first input terminal of the converter. The beginning of the winding 4 is connected to the collector of the power tran

of the resistor 1, and the end of the winding 5 - from the collective to the oscillator mode and to the output

In the winding 8 of the power transformer 3, an alternating voltage and jji are formed (Fig. 2, the time interval). When appearing at the output of the generator 11 control pulses, the posi- tion of the power transistor 2. The emitters of the power transistors are connected to the second input terminal of the converter. The base-emitter junctions of the power transistors are shunted by reverse diodes 15 and 16.

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At the time t (Fig. 2), control transistors 9 and 10 open and shunt the base-emitter junctions of power transistors 1 and 2. Generation ceases and the voltage on the output winding 8 of power transformer 3 becomes zero (Fig. , time interval from, c). At the output of the distributor 12 pulses, a positive voltage UQ appears, and the voltage Uj takes a zero value. In this case, the driving transistor 14 is closed, and the transistor 13 is opened. As soon as the output voltage of the control pulse generator 11 becomes zero (Fig. 2, time t), the control transistors 9 and 10 close and the power transistor 1 opens by applying a positive voltage to the base through the resistor 23 and the open transistor 13 The converter enters the mode of the autogenerator, and on the output winding 8

The start of the winding 6 is connected to the negative output of the power supply through the feedback resistor 17, and the end to the base of the power transistor 1. The start of the basic winding 7 is connected to the base of the power transistor 2, and the end to the negative output of the power supply through the feedback resistor 18 . The output of the generator of control pulses is connected to the control bases of transistors through resistors 19 and 20. The bases of the driving transistors are connected to the outputs of the distributor 12 pulses through resistors 21 and 22, whose input is connected to the output of the generator 11 of control pulses. The emitters of the starting transistors are connected to the bases of the power transistors, and the collectors of the starting transistors are connected to the midpoint of the primary windings through resistors 23 and 24. Base-emitter transitions

transistors are shunted by reverse diodes 25 and 26.

The voltage converter operates as follows.

After the input voltage u is applied, and g, the voltage U at the output of the generator 11 is zero, and a positive unlocking voltage Ug is applied to the base of the driving transistor 14 (Fig. 2, point to). In this case, the voltage DC is zero and the starting transformer 13 is closed. Through a resistor 24 and an open transistor 14, a positive voltage is applied to the base of the power transistor 2, and it is brought to a conducting state. A change in the current of the primary winding 5 leads to the formation of a voltage on the base windings 7 and 6. At the same time, a base current arises, holding the transistor 2 in a conducting state until it is fully saturated. When the core of the transformer 3 is saturated, the EMF of the base windings 7 and 6 changes sign, whereby the power transistor 2 closes and the power transistor 1 opens. Thus, the voltage converter goes over

In the winding 8 of the power transformer 3, an alternating voltage and jji are formed (Fig. 2, the time interval). With the appearance at the output of the generator 11 control pulses put

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At the time t (Fig. 2), control transistors 9 and 10 open and shunt the base-emitter junctions of power transistors 1 and 2. Generation ceases and the voltage on the output winding 8 of power transformer 3 becomes zero (Fig. , time interval from, c). At the output of the distributor 12 pulses, a positive voltage UQ appears, and the voltage Uj takes a zero value. In this case, the driving transistor 14 is closed, and the transistor 13 is opened. As soon as the output voltage of the control pulse generator 11 becomes zero (Fig. 2, time t), the control transistors 9 and 10 close and the power transistor 1 opens by applying a positive voltage to the base through the resistor 23 and the open transistor 13 The converter enters the mode of the autogenerator, and on the output winding 8

power transformer 3, a positive voltage Ueu is formed (Fig. 2, time interval,).

With the arrival of the next rectangular pulse from the output of the control pulse generator 11 (Fig. 2, time t), the autogeneration of the converter ceases. At the output of the distributor 12 pulses, the voltage and g becomes equal to zero, and the voltage and. adopts a positive sign. The application of the distributor 12 pulses and the starting transistors 13 and 14 ensures that the switching of the core 3 always starts in the required direction, hence the reliability of the converter increases.

reading In this case, the driving transistor 13 is closed, and the transistor 14

opens up. Further, the processes in the 15 pho {5 of the mule of the invention, the voltage generator, are repeated.

Pulse distributor 12 (FIG. 3) consists of trigger 27, inputs R and S of which are connected to the source of a voltage converter, containing a power transformer, retraction from the midpoint of the primary winding1 and of which is connected to the first input terminal of the converter, and extreme ends of the primary winding through the power transistors are connected to the second input of the converter, the feedback windings through the first resistors are connected to the bases of the power transistors, the control input of each power transistor is shunted A switching transistor, the base of which is connected via a second resistor to the output of a control pulse generator, characterized in that, in order to increase reliability by eliminating one-way saturation of a power transformer, two triggering transistors are inserted, each of which is connected through the third resistor between the base of the corresponding power transistor and the first input terminal of the converter and the base is connected via the fourth resistor to the output of the input pulse distributor, whose input is connected to the outputs of a control voltage generator E, through the resistor 28, and input C to the voltage driver U., Input D is connected to: the inverse output Q.

The pulse distributor operates as follows. Assume that the power supply voltage is + E (figure 2, time t,). Then the voltage U takes a positive value. With the arrival of a positive pulse and the input C of trigger 27, the state at the outputs Q and Q of trigger 27 changes, i.e. the voltage and about becomes positive, and the voltage U equals zero (Fig. 2, time point t,). With the arrival of the next positive pulse (Fig. 2, time t), the trigger 27 returns to the initial state, i.e. DO voltage becomes zero, and Ug takes a positive value. Further, the processes in the pulse distributor are repeated.

If a voltage converter is used as a generator

the generator of rectangular pulses and contains a comparator 29 and the time specifying the KS-chain (resistor 30 and terminal - 31), which determines the generation frequency.

The use of the pulse distributor 12 and the starting transistors 13 and 14 ensures that the switching of the core 3 always starts in the required direction, hence the reliability of the converter is increased.

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A voltage converter containing a power transformer, retracted from the midpoint of the primary winding1 and which is connected to the first input terminal of the converter, and the extreme leads of the primary winding through power transistors are connected to the second input output of the converter, the feedback windings are connected to the bases of the power transistors , the control input of each power transistor is shunted by a control transistor, the base of which is connected via a second resistor to the output of the control and pulses, characterized in that, in order to increase reliability by eliminating unilateral saturation of the power transformer, two triggering transistors are introduced, each of which is connected through the third resistor between the base of the corresponding power transistor and the first input terminal of the converter and the base is connected via the fourth resistor to the output of the inserted distributor pulses, the input of which is connected to the outputs of the generator control

a series of pulses can be used for the resulting pulses, with the opposing-drive of the control signal (Fig. 4). The generator 11 control pulses is fulfilled in the form of relaxation

An additional diode is connected in parallel with the control input of each triggering transistor.

An additional diode is connected in parallel with the control input of each triggering transistor.

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Editor V. Petrash

Compiled by V. Moin Tehred M. Didyk

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Proofreader L. Pilipenko

Claims (1)

Claim Voltage converter comprising a power transformer, a center tap of the primary winding zhitelnogo voltage E _n + via resistor 28 and input C - a builder voltage ϋψ, Log D is connected to the inverted output Q. The pulse distributor operates as follows. Suppose that after applying the supply voltage + E ϋ ψ = ϋ _π = Ο (Fig. 2, time instant g,). Then the voltage U _B takes a positive value. With the arrival of a positive pulse U _q at the input C of trigger 27, the state at the outputs Q and Q of trigger 27 changes, i.e. the voltage U _o becomes positive, and the voltage U _B becomes equal to zero (figure 2, time t,). With the arrival of the next positive pulse (Fig. 2, the time tj trigger 27 returns to its original state, that is, the voltage U _a becomes equal to zero, and U _g takes a positive value. Next, the processes in the pulse distributor are repeated. In the case of using a voltage converter as a pulse series generator, a control signal source can be used (Fig. 4). The control pulse generator 11 is designed as a relaxation pulse which is connected to the first input terminal of the converter, and the extreme terminals of the primary winding through power transistors are connected to the second input terminal of the converter, feedback windings through the first resistors are connected to the bases of the power transistors, the control input of each power transistor is shunted by the control a transistor, the base of which is connected through a second resistor to the output of the control pulse generator, characterized in that, for the purpose of To increase reliability by eliminating one-sided saturation of the power transformer, two starting transistors are introduced, each of which is connected through the third resistor between the base of the corresponding power transistor and the first input output of the converter and the base through a fourth resistor to the output of the input pulse distributor, the input of which is connected to the outputs of the control generator pulses, and counter-parallel to the control input of each triggering transistor includes an additional diode. figure 1 ϋφ 1 1 I to Ts Cm t 1 1 1 f 1 eleven eleven eleven eleven li h t 1 - - t 1 1 t ι ι (Riga 2 P72562 Fig.Z