SU476642A1 - A device for generating control pulses - Google Patents

Description

The proposed device can be used as a generator of control pulses of high power thyristor converters that have a large number of parallel and serially connected thyristors in phase (group).

In order to ensure the normal starting modes of such converters, as well as their stable operation in all operating modes, the duration of the control pulses applied to the control electrodes of the thyristors must be equal to the duration of the conducting state of the thyristors, and so on. when adjusting the converter, the control pulse duration must vary within wide limits. At the same time, in order to enable the group connection of the thyristors, the impulse of the control current of the thyristor must have an amplitude several times greater than the value of the rated switching current of the thyristor with a high leading edge slope.

To reduce the power dissipated by the thyristor control transition, reduce the power of the control pulse generator and optimally combine the requirements for the duration, amplitude and the leading edge of the control pulses, special-form control current pulses are used - with large amplitude and forward slope

the front in the initial part and the subsequent section of a long duration with the amplitude necessary only for supporting the on state of the thyristor.

Devices for generating control pulses are known that contain a large number of elements, auxiliary circuits and consume a lot of power.

The purpose of the invention is to increase the efficiency of the pulse shaper, which is achieved by connecting one choke to the cathode bus of the thyristor groups and the other to the power supply and through the diode to the plates of the switching capacitor, parallel to one of the resistors, an additional capacitor is connected.

Pa figs. 1 is a circuit diagram of a pulser; in fig. 2 is a timing diagram of the voltage and current across the elements of the device.

A device for shaping control pulses consists of six main tsiii, which represent a series-connected tunnel and primary windings of pulse transformers (or groups of pulse transformers), as well as circuits for recharging and switching capacitor.

The main circuits are the tyrstors 1-6 and the pulse transformers 7-12. The restarting of the switching capacitor 13 is carried out using thyristors 14 and 15 from the power source 16 through one of the main prices and the choke 17. The recharge current stored in the choke 17 closes through one of the diodes 18 and 19 to one of the main circuits, forms in it a section of long duration and small amplitude of the control pulse. The front part of the control pulse is formed by charging the capacitor 20 through one of the diodes 21, 22, one of the main circuits and the resistor 23.

Through the resistor 24, the capacitor 20 is discharged, but the circuit of the fordshirovanie front of the pulse to the next cycle. Thyristor control transitions 1 ... 6 and

14, 15 are connected to the puller pulse inlet 25. The PI pulses of the control current of a special form are removed from the secondary windings of the pulse transformers 7 ... 12.

The device works as follows.

The thyristors 1-6 are supplied with control pulses from the output of the driver 25, respectively, I ... I control channels. At the same time, the pulses are applied to the switches 14,

15, with the thyristor 14 having pulses of II, IV n VI channels, and a thyristor 15 pulses of I, III and V control channels. Without adjusting the transducer, the phase shift between the channels is 60 electr. In the initial state, when the driver 25 is driven, there are no currents in the generator elements. Capacitors are not charged.

Suppose that after unlocking the former 25, the first control pulse IV dripped. The thyristors 4 and 14 are turned on and the capacitor 13 begins to charge through transformers 10, 9, choke 17 from the power source 16. At that point in time when the voltage on the capacitor becomes equal to the voltage of the power source, the diode 19 opens, bypassing the power source

16, the thyristor 14, the capacitor 13 and the current in the choke 17 begin to decrease through the diode 19. After 60 al. after switching on the thyristors 4 and 14, the thyristors 5 and 15 are turned on. In this case, the voltage of the capacitor 13 is applied in the opposite direction to the thyristor 14, the main circuit with the thyristor 4 and to the value: resistor 23, capacitor 20, diode 21.

The thyristor 4 is turned off by the applied voltage, and the capacitor 20 is charged. The magnitude of the current pulse, which is then formed in the main circuit with thyristor 5, is determined by the sum of the commutation currents of the SC1P1 thyristor 4n charge of the capacitor 20. The rate of rise of these currents determines the steepness of the leading edge of the pulse. Simultaneously with the described processes, when thyristors 5, 15 are turned on, capacitor 13 is recharged from source 16 through choke 17.

ii the moment of time when the voltage ia con11, the sensor 13 reaches the value of the voltage source iptapi 16 with polarity indicated in fig. 1 in brackets, diode 18 opens, the current through the source is 16

the choke 17, the bottom 18, the transformers 11, 10, the thyristor 5.

Through 60 el. hail, the thyristors 6 and 14 are turned on; in the load of the thyristor 6, the front part of the pulse is formed by the sum of the switching currents of the thyristor 5 and the charge of the capacitor 20, which is previously discharged to zero through the resistor 24.

At the time when the voltage

on the capacitor 13 again becomes equal to the voltage of the power source 6, the diode 19 comes into operation, the power source 16 is turned off, the throttle current 17 decreases until the thyristors 1 and 15 are turned on.

When thyristors 1 and 15 are turned on, the processes proceed as well as when thyristors 5 and 15 are turned on, when thyristors 2 and 14 are turned on, like switching on thyristors 6 and 14. and so on.

Subject invention

A device for generating a control pulse, containing two groups of pulse transformers, connected to a switch. Alternately by means of tirpstors through a switching capacitor and a choke to the terminal of the power supply terminal, additional thyristors, which pass through; , characterized in that, in order to improve the parameters of the pulses, said choke is connected to the cathode bus of the thyristor groups by a single point,; i another point to the source nitani and via diodes to a switching kopdensatora the plates, and the pair .chelpo pz one of said resistors Eklyuchep dopolpitelny capacitor.

X. ::::

± -: and

-and

73

-5Ж

 t1

S1.5

R

WITH

t

2i

: x:

y .

P

o / i (- g-,

I I

 I

  ;

JIi „. .L

-L.

Droe-tone 17

SfT opu4Hos

mpoHCC pfff

. one