SU1312704A1 - Frequency doubler - Google Patents

Abstract

The invention relates to a converter technique and m. used in the development of power sources hand tools. OfS The aim of the invention is to improve the input power factor by reducing the phase angle between the supply voltage and the input current along the fundamental harmonic. The device contains thyristor bridges 1-8, which are controlled by the corresponding pulse shapers 13, 19. Each of the pulse shapers contains an intermediate tr-p 14, a diode 15, a transistor 17 and a pulse tr-p 18. One of the groups of thyristors 1 - Each bridge is shunted by resistors And, 12, which allows you to remove the necessary reverse control voltage from the thyristors of the opposite group of the same bridge. 2 na. +) with (L Fig. On 1iZ

Description

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The invention relates to power converter technology and can be used, for example, in the development of sources of secondary power supply for electric motors of the construction of milling, fugovalny and pazovalny woodworking machines.

The aim of the invention is to improve the input power factor of the device by reducing the phase angle between the supply voltage and the output current along the fundamental harmonic.

Fig. I shows a variant of directly connecting the doubler bridges to the corresponding voltages of a three-phase four-wire network; figure 2 - frequency doubler, receiving power from a three-phase network through the converter number of phases.

The frequency doubler contains two thyristor bridges on thyristors 1-8, a matching transformer 9, to the secondary winding of which a load 10 is connected. Resistors II and 12 bypass anode thyristors. The pulse shaper 13 consists of an intermediate transformer 14, a diode 15, a parallel circuit 16, a transistor 17 n of a pulse transformer 18.

The primary winding of the pulse transformer 18 is connected via a transistor 17 to a constant voltage source. The connection of this transformer is galvanic isolation and multiplication of pulses for two simultaneously opening thyristors in the bridge, therefore it has two secondary windings.

Resistors 11 and 12 can be connected in parallel with the cathode thyristors, and the voltage for the control units can be removed from the anode thyristors, as shown in Fig. 2. The remaining formers 19 pulses are made similarly.

The converter 20 of the number of phases converts the three-phase mains voltage into a symmetrical two-phase, if the load of the converter is single-phase, or six-phase, if the output of the converter is three-phase.

The Converter operates as follows.

Suppose that at some time the current flows from the pole B (figure 1)

A2

through the thyristor 4, the primary winding of the output power transformer 9, then through the thyristor 2 and to the pole C. When the current in this circuit breaks, after the mains voltage changes sign, the thyristors 2 and 4 are closed in a natural way, the current flows from poles C through resistors 1I and 12 to pole B. At the same time, the voltage

From the resistor 12 through the primary winding of the transformer 9 is fed to the thyristor 4 in the opposite direction, as well as to the transformer 14, the transistor 17 is opened and current from the secondary windings of the pulse transformer 18 is fed into the control circuit of thyristors 6 and 8, opening them.

In this case, the current flows from the pole O to pole A and along the primary winding of the power transformer 9 in the opposite direction. Upon termination of the current through the thyristors 6 and 8 and the appearance on them and on the resistor II of the reverse voltage with the help of the driver 19

the pulses are opened by thyristors 1 and 3. Next, the thyristors 5 and 7 are opened in the same way, and after they are closed, the thyristors 2 and 4 are opened and the cycle is repeated. There are four pulse formers in the device, their circuits are the same, and their transistor circuits are powered from a common DC source.

Frequency doubler pictured

figure 2, works similarly. There is no output power transformer 9, but a converter 20 for the number of phases is needed.

Claims (1)

Invention Formula A frequency doubler containing two thyristor bridges with anodic and cathodic thyristor groups in each bridges, bridges AC outputs form power input pins for connecting to a two-phase AC network, DC outputs through a matching transformer or directly connected to output pins in the appropriate polarity, and the control unit is in the form of a set of pulse drivers for controlling bridge thyristors, distinguished by the fact that, in order to improve the input power factor and by reducing the shear angle, the inputs of the first pair of impulse formers3131 owls are connected to the power electrodes of the thyristors of the anodic or cathodic group of the first bridge, the outputs of each of these drivers are connected to the control inputs of a pair of diagonally arranged thyristors of the second bridge, the inputs of the second pair of pulse drivers are connected to the power electrodes of the anode or cathode thyristors The second group of the bridge, the outputs of each of these drivers are connected to the control inputs of a pair of diagonally located types, the first bridge and the resistors, respectively, of the cathode or anode groups of the first and second bridges are shunted by the input resistors. FIG. 2 Hazu Editor A. Shandor Compiler 1.Mytsyk Tehred L. Serdyukova Proofreader A.T. Order 1978/54 Circulation 661 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, Projecto st., 4