SU752680A2 - Three-phase rectifier - Google Patents

Description

voltage of which is 2.73, as well as twelve valves 6-17.

FIG. 1.6 shows a vector diagram of the linear voltages of the secondary windings of the transformer; in fig. 2, a is the rectified voltage curve; in fig. 2.6, 8, g, d, e, g, 3 are the curves of the currents flowing through the valves and secondary windings of both six-beam stars, when the rectifier is operating at the active load without taking into account the switching angles.

The rectifier works as follows.

At time ti (see Fig. 2, a), the magnitude of the linear voltage EI of the phases a and C4 (see Fig. 1) becomes greater than the linear application of the 12 phases az n b, therefore the valve begins to hold 17 (see fig. 2,6). Then after 30 el. the hail at time tz led to 1 line of linear voltage EZ of phases 22 and 1 becomes greater than the linear voltage EI, and valve 7 comes into operation (see Fig. 2, c). After 30 el.grad. after the time tz, at the time time t, the magnitude of the linear voltage E of the phases Z2 and g / 1 becomes greater than 2 and Vepptl 6 comes into play (see Fig. 2, d). Next come into operation in turn valves 16, 15 (see fg. 2, d, e). On fng. 2, the current curve, flowing, is shown through one of the phases of the secondary windings of the six-star Xz star, g / 2, Zz, az, bz, Cz, and FIG. 2, the curve of the current in phase c of the second six-beam star xi, y, zi, a, b, C4.

The average value of the current flowing through the valves in the rectified sections is equal to /.

The rectified voltage curve (see Fig. 2, a) is obtained from the instantaneous values of the linear voltages of two six-beam "stars" of the operating secondary windings of the transformer (the curve is highlighted). The typical power of a transformer does not exceed the values in known rectification circuits.

The possibility of eliminating equalization reactors is achieved due to the fact that the proposed rectification scheme can drop out of the twelve-phase mode with a variation of the amplitudes of the secondary parameters / 2-1 / 2

. 100% (about scientific research institute reaching /

28%), trgda as known drops out at 2- / 3 jQQ (y (about 13.5%).

A schematic diagram of a rectifier with a surge reactor is shown in FIG. 3

The converter is additionally equipped with a balancing choke 18, on the magnetic core of which there are two windings 19-24 with a midpoint.

FIG. 4, and the curves of the rectified voltage and linear stresses l, formed by two six-star stars, are shown; FIG. 4.6, в, г, д, е, ж, з are the curves of the currents flowing through the valves, and the secondary windings of both six-beam stars when operating the rectifier for an active load without taking into account the switching angles. The rectifier works as follows.

At time point o (see Fig. 4, a), the magnitudes of the linear voltages of the phases az, b, and EI phases az, C4 are the greatest and due to their equalization by the winding 22 of equalizing throttle 18, the valves 17 and 16 simultaneously flow Fig. 4.6, c), each of which conducts half of the load current Id- Until the moment ti, the left half of the winding 22 of equalizing throttles 18

by instantaneous value subtracts from i2

value, and the rights add

this value to EI, after the moment i, until the moment tz, this process goes in reverse order (subtracts the rights, the left adds). At the same time, in the other sections of the surge reactor the same emfs will be transformed, but they will not participate in the passage of current through them.

since the linear voltages on the remaining phases are significantly lower in their instantaneous values. At time tz, the linear voltage .12 becomes less than EZ of the phases Zz, x, and the voltage equalization between E and EI is produced by the right half of section 22, which deducts

  off, and the left half of the first

2

to 2,

sections that adds

-2

and the valve 16 is operated in parallel with the valve 6, since the valve 17 is closed. From the time point C to the moment / 4 the process of leveling the voltage between E

and 2 with the left half of the winding 19 and the right half of the winding 12 of the equalizing throttle 18 goes in reverse order (left subtracts, the rights add).

Further at time ti, E becomes

less than from phases r2, g / b and the equalization of voltages between 2 and 3 is already carried out by the windings 19 of equalizing throttles 18 (left subtracts, the rights add up to time 5), and valve 6 operates in parallel with valve 7, i.e valve 16 is closed.

From the moment of time i to the moment i, the voltage leveling between 2 and s windings of the first section of the surge reactor goes in the reverse order (the left one adds, the rights are subtracted). At the time t, the amplitude 2 becomes less than 4 phases & C4, and the voltage between C and 4 is equalized

half winding 19, which subtracts,

and the left half of the winding 23, which adds, and the valve 15 is in operation and in parallel with the valve 7, since the valve 6 is closed (see Fig. 4, d, e). At the moment of the t-section of the surge reactor, the voltages EZ w are equalized. E обрат is in reverse order, and at the time of / 8 instead of 3, EZ enters into operation, and valve 14 instead of valve 7 starts to be carried out, etc.

From the work of the scheme it is clear that every 30.el. hail, there is a mixing of the valves, and at any time, two parallel valves flow around the charging current for a duration of conductivity of each 60 el. hail, which is 1 for the rectified current.

FIG. 4, s, 3, the curves of the currents flowing through the phases of both six "stars", namely z- and x, are given.

The magnetization of the surge reactor over the period of the supply frequency of the network is re-magnetized six times.

The current flowing through the semi-windings

equilibrium reactor, is equal to -7- i i.

anode current ventil.

A three-phase rectifier circuit providing an eighteen-pulse rectification is shown in FIG. 5, a; vector diagram of the voltage of the secondary windings of the transformer - in fig. 5.6; rectified voltage curve in FIG. 6, a; the curves of the currents flowing through the valves and the secondary windings during the operation of the rectifier to the active load without taking into account the switching angles - in FIG. 6.6, c, d, e, f, h, h.

Two secondary windings 25, 26 of transformer 1 and valves 27-32 are additionally introduced into the circuit.

The rectification scheme works as follows.

At time ii (see Fig. 6, a), the magnitude of the linear voltage fi phases az and Ci (see fig. 5) becomes greater than the linear voltage .Eig phases az and X2, therefore, begins to conduct instead of valve 27, valve 13 (see FIG. 6.6). Then after 20 email. hail, at time 4, the magnitude of the line voltage E of the phases Zj and Xf becomes more positive than EI, and the valve 10 enters (see Fig. 6, c). After 20 el. hail, after time 4, at time ts, the magnitude of the voltage E. of phases 34 and Cs becomes greater than 2 and the valve 32 comes into operation (see Fig. 6, d).

Further, at time 4, the magnitude of the linear voltage 4 of the phases 2.1 and g / 6 becomes greater than HL, and the valve I begins to conduct (Fig. 6, e), etc.

It follows from the operation of the rectifier circuit that the valves conduct current for 20 al. hail, and the average value of the current flowing through the valves in the range of you

Curve

constitutes

ave,

T

The rectifying voltage (see Fig. 6, a) is obtained from the instantaneous values of the secondary voltages of six-shells of stars (the curve is highlighted). FIG. 6, e, g, 3 are the curves of the currents flowing in the second. coil windings of brilliant stars.

Claims (3)

1. Three-phase rectifier auth. St. No. 265254, characterized in that, in order to obtain a twelve-pulse rectification, it is equipped with two additional secondary windings connected in a "star so that the opposite ends of the windings are combined with respect to the main ones, and the common points are connected to the output terminals, and six pre-additional valves mi, each phase of one additional voltage of the secondary winding of the transformer is connected to the combined anodes (cathodes) of two additional gates through which it is connected to the opposite phases of the second additional volt ary winding. 2. The rectifier according to claim 1, that is, in order to improve the external characteristics, it is equipped with an equalizer choke containing a gap of windings with a middle point, their extreme points are connected to the anodes (cathodes) valves, and the middle points with the phases of the first main and additional windings. 3. The rectifier according to claim 1, except for the fact that, in order to obtain an eighteen-pulse rectifier, it is equipped with two additional windings connected into "stars" so that one of them has its beginnings, and the other the ends of the windings, and the common points are connected to one output terminal and six valves, each phase of the additional windings connected via a valve to the corresponding phase of the corresponding main winding, the common point of which is connected to another output so that the homogeneous valve electrodes are connected. 1g five Ei2 f-f fz 3 ff fj C 7 8 3 10 11 EIZ Ltd l i-str ABOUT n 1.87 ABC Ht U1 1S s Ctf ff 7y s y 5 / ywyrsyr VZwy / a -t EII 7 2 3 f). ES s .1 Eg Eg 10 11 f-n   n 187 r IB, 1vg ie. iTl / i ix, t fd T1ug n. t . ABC l ud g EI EZ EZ Elf ES EB 7 fg Eg E-, 0 f f fyj fr n n Lb 13 n n n n n n