SU610260A1 - Arrangement for pulse-phase control of thyristors - Google Patents

Description

(54) DEVICE FOR PHASE-IMPULSE CONTROL

TIRISTORS

The invention relates to elements of converter control systems and can be used in a thyristor controlled electric drive where a change in the current and voltage of the thyristor converters is required by a change in the moment the thyristors are turned on. Apparatuses for phase-impulse control of thyristor converters are known, which comprise a reference saw voltage driver, a comparison device, and an output pulse driver. A device is known in which a capacitor charge from a constant voltage source is used to create a sawtooth voltage and then discharged through a diode switch IJ. However, in the case of forming a saw in one half cycle of the synchronizing voltage, the diode switches have a limited control range, and the control range depends on the frequency variation and the voltage of the synchronizing signal. The closest technical resolution to the invention is a device comprising a sawtooth generator and a generator, which includes a capacitor and a transistor switch connected parallel to the co-sensor, a zero-body on the transistor and the output stage {2 |. However, when the control signal is equal to zero, the null-organ does not operate at the moment when the synchronizing voltage passes through zero, but after a certain time interval determined by the rise time of the saw to the level of voltage drop at the base-smitter transition of the transistor zero organ. Thus, the delay angle that narrows down the range of adjustments appears and, when using such devices for controlling multiphase thyristor converters, contributes to the appearance of control asymmetry due to deviations of the static characteristics of the zero-organ transistors. The aim of the invention is to expand the control range and increase the noise immunity of the device. This is achieved in that the device for the phase-pulse thyristor control, comprising a sawtooth generator, comprising a capacitor and a transistor switch connected in parallel to the capacitor, a synchronization voltage source connected to the emitter base circuit of the transistor switch, the source

control voltage1 (and, having a common point with a source of synchronizing voltage, a zero-body transistor, the emitter-rotor circuit of which is connected to the sawtooth and control voltage sources, and an output stage, a diode is inserted, one electrode of which is connected to the junction point the emitter of the transistor switch and the capacitor, and the other electrode to the common point of control sources, 1, its synchronization voltage, to which the basic circuit of the transistor switch is also connected.

FIG. 1 shows a circuit diagram of the device; in fig. 2 - timing charts of the device.

The device for phase-thyristor control of the thyristors contains a source of synchronizing voltage 1, through resistors 2 and 3 connected to the emigrant-base circuit of the transistor switch 4, a sawtooth generator, which includes a series-connected current-stabilizing element 5, a condiser 6 and a diode 7, and parallel to the capacitor 6, a transistor switch 4 is turned on. The device also contains a null organ on the resistor 8 and the transistor 9. the source of the control signal 10, the output stage I, and the power source 12.

The pulse-phase control device operates as follows.

During the positive half-wave of the synchronizing voltage, the transistor switch 4 is locked by the voltage drop across the open diode 7. At this time, the capacitor 6 is charged by the constant current of the current-stabilizing element 5. If the control voltage (Uy) is greater than the maximum amplitude of the saw, the transistor 9 is locked and the charge of the capacitor 6 will occur until the synchronization voltage changes sign. In this case, transistor switch 4 is opened, diode 7 is locked, and capacitor 6 is discharged until the voltage drops on open transistor switch 4. The next time the sync voltage goes through zero (the transistor switch 4 is locked, and diode 7 is unlocked), the voltage on The base of the transistor 9 is increased in a jump, since the condiodeb is charged during a whole half-period to a certain voltage equal to the voltage drop on the open transistor switch 4.

8 further, the capacitor 6 is charged from the current-stabilizing element, 5 and the whole process is repeated. If yi and m transistor

9 opens and, thereby, turns on the output stage 11 (for example, a burst generator).

If the control signal is zero (Uy 0), then the residual voltage on the capacitor 6 is enough to open the transistor 9, therefore, the output stage And turns on when the sync voltage goes through zero and the regulation can start almost from 0 ° to 180 ° C.

If the control signal is equal to zero, the false zero-body actuation during the non-working half-period is excluded, since the negative half-wave of the synchronizing voltage is applied to the base-emitter junction, transistor 9, and the transistor 9 is reliably closed.

When the device operates in the large volume range of the amplitude of the synchronization voltage, the diode between the base of the transistor 9 and the capacitor 6 can be switched on to protect the base-emitter transition of the transistor 9 from the reverse voltage.

At the same time, the threshold of the zero-body increases, and to compensate for it, it is necessary to turn on the diode in series with the transistor switch 4, thereby increasing Up. 1 dotted line. To protect the transistor switch 4 from a large direct current, a zener diode can be switched on through the base-emitter junction as a diode 7.

Thus, the resulting device is a simple and reliable scheme that provides a wide range of adjustment of the switching angle of the power thyristor converters, which significantly improves the technical and economic performance of the latter.

Claims (2)

1.Patent NDP No. 54761 H 02 M / 08,. 2. Dinnel A. A. and Petrenko V. I. Schemes of periodic reference voltage generators for thyristor converter control systems. Sat “Special electric drive systems. Permian. 1968. Issue 3.  / l 7 " g f