SU744871A1 - Ac-to-dc converter - Google Patents

Description

(54) AC VOLTAGE CONVERTER

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The invention relates to the field of converter technology and can be used in power sources.

AC-to-DC converters are known that provide twelve-fold pulsations of rectified voltage 1,

However, such converters are complex and have increased power of equalization reactors.

The known AC / DC converter contains a three-phase transformer with two secondary windings connected in stars, the common points of which are connected to the output terminals, and six gates connecting each phase of one secondary winding to two opposite phases of the other -2.

A disadvantage of the known converter is the presence of large output voltage ripples, as it provides only six times the voltage of the rectified voltage.

The aim of the invention is to reduce the output voltage ripple. The aim is achieved by providing six additional valves and a balancing reactor, on the magnetic core of which there are six windings with a midpoint connected to the end of the corresponding secondary winding, each of which is made

10 by tapping, at the same time, the ends of the windings of the surge reactor, connected to each phase of the first winding of the transformer, are connected to the tapping of the opposite phases of the second through the valves connected in the opposite direction

15, the transformer windings, and the ends of the windings of the surge reactor connected to each phase of the second winding of the transformer, are connected through the valves connected in the forward direction to the outlets of the opposite phases of the first winding of the transformer.

FIG. 1 given circuit diagram of the converter;

25 in FIG. Figure 2 shows a vector diagram of the linear voltages of the secondary windings; in fig. Over - rectified curves, stress on load and linear stresses, formed by Q two stars; in fig. 36,

c, d, d, e, g are the curves of the currents flowing through: the valves and the secondary windings of the stars during the operation of the rectifier to the active load without taking into account the switching angles.

The converter contains a three-phase transformer 1 with secondary windings 2-7, a balancing reactor 8 with windings 9-14, valves 1526.

The rectifier scheme works as follows.

At time t (Fig. 3a), the linear voltages formed by the phases axi b, y / and E formed by the phases OJC are the largest in amplitude And, due to their equalization by the winding 9 of the equalizing reactor 8, half the amplitude is carried out. load current Id valves 15 and 16 {see Fig.36, c). Up to the moment t, the left half of the winding 9 is equalized: the first reactor 8 subtracts the instantaneous value from Е / value. ., but

rights - adds this value to KE, after the moment t to the moment tg this process goes in reverse order (rights - subtracts, left adds), at the same time, the same emf will transform in other windings of the equalization reactor 8, but they will not participate during the passage of the load current, since the linear voltages generated by other phases, or significantly lower in their instantaneous values, or have negative values with respect to the direction of conduction of the valves. After the time point tg, the linear voltage Eyg becomes less than Ed, formed by phase 1 and Ci and O-, due to which the stress leveling; between Eu and E is produced by the right half of the winding 9, which continues to read f from E, but already the value of i and the left half of the winding 14

which adds this value to Eg, and the valve 16 operates in parallel with the valve 25, since the valve 15 is closed (see Fig. 3g). From time tj to time t, the alignment process between E and E goes in reverse order (the left half of winding 14 subtracts, the right half of winding 9 adds). Further at time t, the instantaneous value E becomes less than E formed by phases C and , voltage equalization between E and E3 is performed by winding 14 of the cutting reactor (the left half is subtracted, the right is added), and

the valve 25 operates in parallel with the valve 26, since the valve 26 is closed (see Fig. A), then after the time ts, the alignment process is reversed, etc. From the work schegll it is clear that through

every 30 e-mail there is a change in the operation of the valves, and at any time two parallel operating valves flow around the load current for a duration of conduction

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FIG. The curves of currents flowing through parts of the windings of the phases, e.g. The magnetic core of the surge reactor in the device is re-magnetized six times during the period of the mains supply frequency.

The magnitude of the current flowing through the windings of the surge reactor is equal to 75 Gg / i.e. anode current venti .-, Au

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Claims (2)

Invention Formula An AC-DC converter containing a three-phase transformer with two secondary windings connected in stars whose common points are connected to the output terminals, and six gates connecting each phase of one secondary winding to two different phases of the other, different in that In order to reduce output voltage ripple, it is equipped with six additional valves and a balancing reactor, on the magnetic core of which there are six windings with a midpoint connected to the end of each secondary winding, each of which is made with a tap, the ends of the windings of the surge reactor connected to each phase of the first winding of the transformer through valves connected in the opposite direction are connected to the outlet of the opposite phases of the second winding of the transformer, and the ends of the windings of the balance reactor connected to each phase of the second winding of the transformer, through valves connected in the forward direction, are connected to taps of the opposite phases of the first winding of the transformer. Information sources, taken into account in the examination 1, Kaganov I.L. Electronic and -ipHHMe converters. Part No. M., Gosenergoizdat, 1956. 02. USSR author's certificate No. 265254, cl. H 02 M 7/00, 14.11.66. 4t . fi f Er s; ciOMCs I r s Ej 8 9 „e 15  ,--four/ 1S Zf r 26 Is 1 Hhh well 1 / jjj