SU40445A1 - Device for stabilizing the voltage of rectified current - Google Patents

Description

Rectifying installations are already known, in which the rectified voltage of the current is kept constant due to the use of various relays acting on the modules, which change the firing angle of the controlled valves used in the rectifier, but usually such devices are complex and not very sensitive. Therefore, in the present invention, it is intended to achieve stabilization of the first-voltage voltage rectifier, using a special, specially connected sensitive differential reactive coil.

In FIG. 1 shows an exemplary schematic diagram of the proposed device for stabilizing the rectified voltage of a current; FIG. 2 is a grid voltage vector diagram; FIG. 3 is a graph showing the change in current in the windings of the specified differential reactive coil.

In drawing 7, it denotes an alternating current circuit, 2 — DC busbars, a 3-mercury rectifier (the latter is taken three-anode, since a full-wave circuit with an auxiliary valve is used), 4 — controlled anodes, 5 — an auxiliary anode, b-power transformer (single phase), 7-smoothing reactor coil in the rectified current circuit.

(368)

A variable voltage is applied to the grid of controlled anodes 4 by means of a transformer 10, the phase of which determines the ignition angle of the anodes 4 and, therefore, the amount of rectified voltage.

An alternating voltage to the grid transformer 10 is supplied from the transformer 9 through a phase-shifting circuit consisting of active resistance 72 and inductive 13. In FIG. Figure 2 depicts the grid voltage vector diagram. In this diagram, v, the anode is the voltage vector of the alternating current network, and hence the vector of the anode voltage; u is the voltage vector of the secondary winding of the transformer 9. The angle between v and TJ of the anode is set using an auxiliary phase shifter 19 (the latter may consist, for example, of a combination of active and reactive resistances; denote the corresponding voltage drops on the active resistance {and 72 and on inductive 73. The vector indicates the voltage of the secondary winding of the transformer W. This will be the voltage that is applied to the grid of controlled anodes 4. The angle of ignition of the anodes 4 is determined by the angle of phase shift between the anode grid voltage, i.e. between the vector and the anode V. In the drawing, this angle is indicated by the letter C. It is quite obvious that if the phase shift created by J9 remains constant and the resistance value / 2 also remains constant, the ignition angle will be exclusively the value of inductance / 5,

From the theory of controlled rectifiers, it is known that the voltage delivered by the rectifier can be expressed by the formula for a circuit with a rectifier t valve:

®ш «/ 2

/ .l

. ()

Y „

Here, denotes the amplitude of the rectified alternating voltage; t is the number of phases of the rectifier; ω is the circular frequency of the rectified current; / is the inductance of the anode circuits of the rectifier (this may be, for example, the self-induction of the scattering of a power transformer); / - load current rectifier.

It can be seen from the formula that the whole task of maintaining a constant voltage of a continuous current is to ensure that with the slightest change in f, which is supposed to occur due to a change or /, the inductance of the winding J3

accordingly, it would change so that the firing angle changes caused by it. 1 | 1Vedulated the voltage of the rectified current to its former value. In the present invention, it is intended to make this change in inductance / 5 in the following way. At the core of the reactive coil 7 /, on which the winding J3 is wound, there is a differential winding J4. Each half of the latter consists of the same number of turns. The magnetic permeability of the core of the coil // is 1 therefore the function of the difference of the currents flowing through both halves of the winding 14. When these currents are equal, the resulting vortex winding 74 is zero, the saturation of the core of the coil 7 / is high and its magnetic permeability decreases. Both halves of the differential winding are powered by the rectified voltage

- 2 -

current. In this case, one of the halves of the indicated winding M is connected in series with the active resistance / 5, the other with the controlled lamp / b. On the grid of the lamp} b, using a battery J8 and a potentiometer / 7, some negative bias is specified.

FIG. Fig. 3 shows a graph of the currents in both halves of the differential winding of the coil M depending on the voltage applied to them. The plot of the current flowing through that half of the coil winding 75, which is a purely active resistance, is a straight line passing through the origin. FIG. 3, this line is designated by the letter A. But the current curve flowing through the entire half of the winding, which is connected in series with the controlled lamp J6, has a somewhat different form. So far, the rectified voltage vj, t, where v is the negative bias applied to the grid of the lamp 75, and x is the amplification factor of the lamp 76, the current does not flow through this half of the winding.

When v becomes greater than ii.v, the current through the lamp 75 begins to pass, the age along the straight line, whose tangent to the abscissa axis is

By R. we mean the internal (differential) resistance of the lamp. The graph of the change in current / through the lamp 76, and hence through the corresponding differential differential winding I, is indicated in FIG. 3 by the letter B. In order to obtain a greater sensitivity in the proposed stabilizing device, it is necessary that the internal resistance of the lamp 76 be several times lower than the resistance of 75. In other words, right B should rise much steeper than neye directly A. This can be achieved by choosing a lamp 7 sec. a sufficiently large slope and with a low gain factor.

Let there be an adjustment in which the output voltage is determined by abscissa v (Fig. 3). The degree of saturation of the core of the coil 13 is determined, as mentioned earlier, by the difference of the currents flowing through both halves of the winding 4. In FIG. 3, this difference is represented by segments xx. Considering FIG. 3, it can be seen that any slight changes in the voltage of the rectified current V will cause quite drastic changes in the length of the section xx. It is possible, for example, to ensure that, when v is changed by only a few fractions of a percent, the resulting amperes - turns of the differential winding 14 are measured several times. The changes in the magnetic permeability of the core of the coil 11 caused by this are the cause of the corresponding changes in the inductance of the coil 13.

In this case, if the rectified voltage for some reason gets a tendency to increase, the length xx decreases, the saturation of the core of the coil 13 decreases, the inductance of the latter increases, due to which the ignition angle cp increases so as to paralyze the increase in v.

If, on the contrary, Φ begins to fall, the segment X-X increases, the saturation of the core of the coil 13 increases, its inductance drops and the angle ω decreases so as to raise the r to its previous value. By changing the magnitude of the negative bias applied to the lamp grid b / b, it is possible to shift its characteristic to the position shown in FIG. 3 dotted lines (direct C and D). With such a movement of the characteristics, the proposed device will no longer stabilize the voltage and, but some new voltages.

From this it can be seen that to adjust the magnitude of the rectified current voltage, it suffices to change only the magnitude of the room on the grid of the lamp 16.

At the same time, once set, the value of v is then automatically maintained constant for any variations of E or load current.

The subject matter of the invention.

Claims (3)

1. A device for stabilizing the voltage of a rectified current, characterized by the use of a reactive coil 11 with a winding 14, consisting of two differentially wound parts, connected to a rectified voltage — one in series with the active adjustable resistance 15, and the other in series with the controlled lamp 16, so that when the rectified voltage deviates from the set value, there will be a sharp change in the magnetic resistance of the reactive coil 11 and, therefore, self-induction placed at Anna magnetic circuit winding 13, which causes a phase change applied to the rectifier grid voltage. 2. The form of the apparatus according to claim 1, characterized in that, in order to control the magnitude of the stabilized voltage of the rectified current, the magnitude of the negative bias applied to the grid of the lamp 16 can be varied by, for example, using a potentiometer 77. 3. The form of the device according to paragraphs. 1 and 2, characterized in that the resistance value / 5 is taken several times higher than the internal resistance (differential) of the lamp J6.  T p / / tC fLjj - // L || 5 | l | l | lH CtSiiftr.S - GtLLOA-, .