SU1372536A1 - Stabilized converter - Google Patents

Abstract

The invention relates to electrical engineering, in particular, to sources of secondary power supply for electronic equipment. The purpose of the invention is to simplify and increase the reliability of work. The power part of the device consists of a series-connected single-ended voltage converter with a transistor switch 4 and a power transformer 5 and a power unit 6 for rectifying and filtering. The voltage converter is controlled by the control unit 12, which includes a series-connected measuring body 13, a diode 14, a pulse-width modulator 15 and a pulse amplifier 16 connected via a switching transformer with windings 10, 11 to the control input of the transistor key 4 voltage converter. The device also has a shortened feedback loop consisting of a current transformer with windings 8, 9 and auxiliary rectifying and filtering unit 18. A feature of the device is the implementation of a current transformer and a switching transformer on the same magnetic wire 7. A similar combination of transformers is provided by introducing an additional bias resistor 19 into the transistor control key 4. 1 hp f-ly, 2 ill. cl

Description

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The invention relates to electrical engineering and is intended for use in the implementation of secondary power supply of radio-electronic equipment.

The aim of the invention is to simplify and improve reliability.

FIG. 1 shows a functional diagram of the proposed stabilized converter in combination with another similar converter when connected in parallel; figure 2 - timing diagrams of signals illustrating the operation of the individual composite nodes.

Each and 1Y of converters 1 and 2 (Fig. 1) contains a blocking capacitor 3, a single-ended converter with a transistor switch 4 and a power transformer 5, a power unit 6 for rectifying and filtering performed on the same magnetic core 7, a current transformer with primary 8 and secondary

Noah 9 windings and switching trans-25 rationing auxiliary shortening

formator with 10 primary and 11 secondary windings, control unit 12 with measuring body 13, diode 14, pulse-width modulator 15, pulse amplifier 16 and ballast resistor 17, auxiliary rectifying and filtering unit 18 (with weakly integrating filtering link) and resistor 19 displacement.

Positions 20-23 of the diagram designate the inputs of converters 1 and 2 for connecting the primary sources of constant voltage, and positions 24-27 for their outputs for connecting the load. Positions 28 and 29 are assigned to connecting terminals, using E to parallel the connection of converters 1 and 2.

A voltage converter (gold 4 and 5) and a power unit 6 for rectifying and filtering are included in the converter 2 psi successively between terminals 22, 23 and 26, 27. The first input of the control unit 12 is connected to the terminals 26-27, the second input through the auxiliary The rectifying and filtering unit 18 is equipped with the secondary winding 9 of the current transformer connected by the primary winding 8 to the transistor switch 4 of the voltage converter, and the output through the switching transformer with the windings 10 and 11 to the control input of the transistor switch 4. ResisQ 5

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the displacement torus 19 is connected in series with the secondary winding 11 of the switching transformer.

In the control unit 12, the input of the measuring element 13 is the first input of the unit. The first input of the pulse-width modulator 15 through the diode 14 is connected to the output of the measuring unit 13, and the second input with the series-connected ballast resistor 17 is the second input of the unit. The input of the pulse amplifier 16 is connected to the output of the pulse-width modulator 15, and the output is the output of the block.

The operation of the described converter is based on the classical compensation principle of controlling a transistor single-ended voltage converter in order to maintain the output voltage at a given level.

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feedback loop, eliminating the modulation of the collector current of the transistor switch 4 pulsations and instability of the input voltage

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The output current of the control unit 12, which enters the primary winding 10 of the switching transformer and unlocks the transistor switch 4, is insignificant in magnitude and provides only the initial output mode of the latter of the current cut-off mode. The saturation mode of the transistor switch 4 is achieved by proportional-current feedback, carried out using the winding 8 of the current transformer. As a result, when a working current pulse is formed in the primary winding of the power transformer 5, the current flowing through the secondary winding 11 of the switching transformer is approximately proportional to the current i (fig. 2a) of the collector of the transistor switch 4. When there is a bias resistor 19 in the secondary winding 11 on it, as well as the voltage U (fig. 26) on the secondary winding 9 of the current transformer will also be approximately proportional to the current 14. This property is used to generate a control signal transmitted through the specified loop ATN communication.

Current modulation by pulsations and instability of the supply voltage converter is eliminated as follows. If during the formation of a current pulse i, the input voltage receives, for example, a positive increment, as a result of an increase in the voltage on the primary winding of the power transformer 5, it receives a corresponding increment and the current i flowing through it. In accordance with the above, the increment is also received by the voltage on the winding 9 of the current transformer. The increasing voltage on the winding 9, the passage through the auxiliary unit 18 of the top and filtering and the ballast resistor 17 increases the potential arising from the potential-pulse modulator 15 of the potential corresponding to the amplified error signal of the output voltage of the converter (Fig. 2c, d). As a result, the duty cycle of the following current pulses i, interrupting their amplitude increment, is promptly increased. The described process lasts as long as the amplitude of the current pulses i exceeds the average

the collector current of the transistor switch 4 for the previous mode. Similarly, the correction of the decrease in the amplitude of the current i, caused by a decrease in the input voltage of the converter, is carried out.

In parallel operation of the stabilized converters 1 and 2, their inputs with the outputs 28 and 29 are interconnected, as a result, one common control voltage from that of the measuring bodies 13, which has the following, comes to both of the pulse-width modulators 15 highest output voltage setting.

The measuring element 13 of another stabilized converter is not affected by being disconnected by its diode 14 shifted by reverse voltage. If the currents flowing through the transistor switches 4 in converters 1, 2 are equal, the correction voltages at the outputs of the auxiliary rectifying and filtering units 18 are equal. If the distribution of currents between the converters 1 and 2 is violated, the potentials at the corresponding inputs of the pulse-width modulators 15 are violated, which change

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the duty cycle of the comm1 of transistor switches 4, increasing it in one converter and reducing it in the other. As a result, the violation of the equality of the distribution of currents will be eliminated.

This technical solution for the implementation of a stabilized converter with an auxiliary shortened feedback loop, in which the current transformer is combined on the same magnetic conductor with a switching transformer, is simpler, more reliable and requires smaller dimensions.

Claims (2)

1.Stabilized converter containing single-ended transistor voltage converter and rectifying and filtering power unit connected in series between the input and output terminals of the device, designed to connect respectively the primary source of direct voltage and load, the control unit, the first input of which is connected to the output In the device, the second input of the auxiliary unit of the alternation and filtering is with the secondary winding of the current transformer connected by the primary winding in C The transistor switch circuit of the voltage converter, and the output through the switching transformer - from the control input of the above switch, is characterized in that, in order to simplify and increase the reliability of operation, a bias resistor is inserted in it connected in series with the secondary winding of the switching transformer , and the latter is implemented on the same magnetic circuit as the current transformer. 2. The converter according to claim 1, wherein the control unit contains a measuring unit whose input is the first input of the unit, a pulse-width modulator, the first input of which through a diode is connected to the output of the measuring unit, and the second The input with the series-connected ballast resistor is the second input of the block, and the pulse amplifier, the input of which is connected to the output of a pulse-width modulator, and the output is the output of the block.  "I a 0 Ug H