SU474094A1 - Device for controlling thyristor controllers - Google Patents

Description

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The device can be used in the field of electrical and radio engineering - in controlled rectifiers and variable voltage stabilizers.

Thyristor control devices are known that contain two inhibited blocking oscillators, a keystone driver, a sawtooth generator, and a Schmitt trigger.

The disadvantage of such devices is the asymmetry of the phase shift of the output signals, due to the variation and temperature instability of the circuit elements.

The purpose of the invention is to reduce the asymmetry of the phase shift of the output signals. In the proposed device, this is achieved due to the fact that opposite poles of a trapezoidal form voltage generator and two series-connected resistors are connected to the bases of the blocking generators, the midpoint of which is connected to the Schmitt trigger transistor collector.

FIG. 1 shows a diagram of the proposed device; in fig. Figure 2 shows oscillograms of voltages and currents explaining the principle of operation of the circuit.

The device contains a transformer 1, the primary winding of which is connected to 2 and 3 AC networks, and

The secondary windings are connected to a sawtooth generator 4 and a keystone driver 5. Sawtooth generator output through

the resistor 6 is connected to the Schmitt trigger input 7. The trigger output collector is connected to the midpoint of the resistors 8 and 9 connected in parallel with the output of a keystone generator. Basic Capp inhibited blocking generators 10 P 11 are connected to resistors 8 and 9, respectively. From the output terminals 12, 13 of the generator 10 and 14, 15 of the generator P, the thyristor control pulses are removed. The terminals 6 and 17 of the resistor 6 receive a constant control voltage.

The device works as follows. The terminals 2, 3 of the transformer 1 receive a sinusoidal voltage of an alternating current network (see Fig. 2, Uz-s) The voltage of the secondary windings of this transformer is used to form the keystone voltage on the resistors 8 (U) and 9

(Ug) and to synchronize the sawtooth generator 4 (U). The output voltage of the sawtooth generator is summed with the control voltage (t / ynp) of the resistor 6 and is fed to the input

Schmitt trigger 7 (/ trig), so when the voltage i / ynp changes, the width of the output trigger pulses changes.

The input of the blocking generator 10 receives the total voltage from the output of the trigger and from the resistor 8, to the input of the blocking generator 11 - the total voltage from the output of the trigger and the resistor 9. The supply voltage of the trigger is chosen above the amplitude of the keystone voltage taken from the resistors a and 9, therefore, when the trigger output transistor is closed, the blocking voltage is applied to the bases of the blocking generators through resistors 8 and 9 and the blocking generators are inhibited. Blocking generators can only be generated if the trigger output transistor is open ((vtrig) and the trapezoidal half-period phase of resistors 8 and 9 is respectively negative relative to the midpoint of the connection of resistors 8 and 9 (if the pulses of Us, Ug and triggers), and the blocking generator 11 generates bursts of pulses into positive, and the blocking oscillator 10, into negative half-periods of the network voltage (Tc-3). The width of the bursts of pulses changes as the output width the number of trigger pulses determined by the value of the control; its voltage (see (/ control in Fig. 2, a, b).

FIG. Figure 2 also shows the voltage form at terminals 12, 13 (Uiz-is) and 14, 15 ().

Thus, in the proposed (two-channel) device, the asymmetry is excluded.

phase shift, since the phase angle forming circuit, consisting of a sawtooth voltage generator and a trigger, is single-channel - common to both blocking oscillators that are connected

alternately to a phase-shifting device with the help of a switching element — a trapezoidal voltage generator.

Subject invention

A device for controlling thyristor controllers containing two inhibited blocking oscillators, a keystone driver, a sawtooth generator, and a Schmitt trigger, differing from the fact that, in order to reduce the asymmetry of the phase shift of the output signals, different fields are connected to the bases of the blocking oscillators. a trapezoidal voltage driver and two series-connected resistors, the midpoint of which is connected to the Schmitt trigger output transistor collector.

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