SU1455378A1 - Frequency converter - Google Patents

Abstract

The invention is not applied to electrical engineering and can be used in power supply devices and electric drives. The aim of the invention is to improve the shape of the output signal. The comparator 7 generates wide pulses corresponding to the positive half-waves of the supply voltage, which, together with the output pulses of the pulse-width modulator 5, are converted by the element 6 equivalence in such a way that at its output a signal containing only a sequence of different polarity pulses is generated, which allows to get rid of the appearance in the output signal of two consecutive unipolar pulses and thereby improve the shape of this signal. 3 il.

Description

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The invention relates to electrical engineering and can be used in power supply devices and electric drives.

The aim of the invention is to improve the shape of the output signal.

FIG. 1 shows the functional frequency converter circuit; on |) ig.2 - pulse-width modulator circuit; in fig. 3 - diagrams that show the operation of the converter.

The frequency converter contains a first inverting unit 1 connected in series with a zero control signal, a transformer 2, a second inverting unit 3 with a zero control signal, and also a series-connected rectifier 4, a pulse-width modulator 5 and an EQUALITY element 6, the output of which is connected to the control The unit 3 input, the first input - with the output of the comparator 7, and the second - with the output of the pulse-width modulator 5, the output of which is also connected to the control input of the unit 1. At the same time, the inputs of the unit I, Arathor rectifier 7 and 4 are combined and input transducer, and its output is the output of unit 3.

Blocks J and 3 are made according to a four-arm bridge circuit in which transistors included in the diagonal of the rectifying bridges are used as controllable keys. The EQUALITY element is made on the K155LP5 series microcircuit. Rectifier 4 is made according to the bridge circuit. Comparator 7 is implemented on the K521SAZ chip.

Pulse width modulator 5 is made according to the circuit of Roeer's autogenerator (FIG. 2) and contains a transformer 8 with windings 9-13, transistors 14 and 15 are connected in series to windings 10 and II, and diodes are connected parallel to collector-emitter junction 16 and 17, the base circuit of the transistor 14 is formed by a series-connected winding 9 and resistors 18 and 19, the base circuit of the transistor 15 is formed by a series-connected winding 12 and resistors 20 and 21,

The basic circuits of the transistors are connected to the ECS 22 source, the input for the pulse-width modulator 5 is: IM and 23, and the output are 1455378

MN - clamps 25 and 26. In series with clamps 25 and 26, a resistor 27 and a winding 13 are connected, and in parallel, a resistor 28 and diodes 29 and 30.

The frequency converter works in the following way.

The input voltage of the network and (FIG. 3) is rectified by a rectifier 4 U

Q (FIG. 3) and is fed to the input of the pulse-width modulator 5, which generates pulses Uj (FIG. 3). These pulses control the operation of the block that forms the voltage U

15 (fig.Z).

The comparator 7 generates a signal UY from the input voltage (Fig. 3). EQUALITY 6 transforms signals

and

Uj- and U-, in the control signal

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25

thirty

35

40

45

50

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 unit 3, with the result that a U signal appears at its output (Fig. 3). This signal contains only a sequence of opposite-polarity pulses, since, under the action of element 6, the even half-periods of the output signal change polarity.

Thus, the introduction of a comparator and the EQUALITY element into the frequency converter allows one to eliminate the appearance of two consecutive unipolar pulses in the output signal and thereby improve the shape of this signal.

Claims (1)

Invention Formula A frequency converter containing a serially connected first inverting unit with a zero control signal, a transformer, a second inverting unit with a zero control signal and a series-connected rectifier and pulse-width modulator, made in the form of a Roeur oscillator, the output of which is connected to a control input the first inverting unit with a zero control signal, the inputs of the first inverting unit with a zero control signal and the top of the taps are combined and are input transformer, the output of which is the output of the second inverting unit at zero control signal; characterized in that, in order to improve the output signal form, a comparator and the EQUALITY element are introduced, the first and second inputs of the EQUALITY component of the Comparator 7 generating from the input voltage the signal UY ( FIG. 3). EQUALITY 6 transforms signals and Uj- and U-, in the control signal 0 five 0  unit 3, with the result that a U signal appears at its output (Fig. 3). This signal contains only a sequence of opposite-polarity pulses, since, under the action of element 6, the even half-periods of the output signal change polarity. Thus, the introduction of a comparator and the EQUALITY element into the frequency converter allows one to eliminate the appearance of two consecutive unipolar pulses in the output signal and thereby improve the shape of this signal. Invention Formula A frequency converter containing a serially connected first inverting unit with a zero control signal, a transformer, a second inverting unit with a zero control signal and a series-connected rectifier and pulse-width modulator, made in the form of a Roeur oscillator, the output of which is connected to a control input the first inverting unit with a zero control signal, the inputs of the first inverting unit with a zero control signal and the top tiers are combined and are input reobrazovatel whose output is the output of the second block invertirovgshi at zero control signal; characterized in that, in order to improve the output waveforms and EQUIVALENCE introduced comparator element, the first and second inputs EQUIVALENCE element Cpd 1455378 yen with comparator outputs and latitude-left control signal, but the pulse modulator, respectively, and the output from the control input of the second inverter unit when the nuparator is connected to the input of the inverter unit at the control signal. 23 az f8 TK about d WITH) about 22 about left control signal the comparator input is connected to the input of the first inverter unit at a zero control signal. 2 23 025 of / 3 025 3 70 // P 15 m F P 20 21 oh oh FIG. 2 BUT oh About% oh tfi e o 7 d ABOUT e about 3  about p gp rn f-i p p -1 gp P gp gp n p g i t gp n p g i t FI.5