SU754602A1 - Pulse shaper for control of thyristors - Google Patents

Description

one

A pulse shaper for controlling thyristors relates to converter technology and can be used to generate control pulses in valve converters with a large number of serially or parallelly connected 5 thyristors.

Known pulse shapers for

control thyristors [1], containing a charging chain of a thyristor and a storage capacitor and a discharge chain including a resistor and a choke. ^ten

The disadvantage of such shapers is the complexity of the scheme.

Of the known pulse shaping to control the thyristors closest to the proposed technical _{susch-] 5} NOSTA shaper is [2], comprising an auxiliary thyristor connected in series, the output pulse transformers and an energy storage capacitor. The secondary windings of the output pulse transformers through diodes are connected to the cathodes and control electrodes of the power thyristors. Storage capacitor is shunted by a discharge chain consisting of

2

connected resistor and choke. At the core of the choke there is an additional winding that is shorted.

However, this device also has disadvantages:

The unreliability of the circuit, due to the fact that with voltage deviations of the power supply, changes in the characteristics of the circuit elements, or due to interference, modes are possible in which during the time when the auxiliary thyristor is open, the current through the discharge circuit rises to a value greater than the holding current. There is a failure of the mode of operation of the shaper.

At high frequencies, the circuit is inoperable. due to the fact that the discharge chain shunting the storage capacitor contains a choke with a shorted winding, due to which the discharge time of the storage capacitor exceeds the operating frequency of the pulse shaper.

The aim of the invention is to increase

the reliability of the pulse shaper and the expansion of the frequency range of the driver.

754602

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This is achieved by the fact that a pulse shaper for controlling thyristors, containing a series-connected auxiliary thyristor, an output pulse transformer, the secondary windings of which through diodes are connected to cathodes and control electrodes of power thyristors, and a storage capacitor, shunted by a discharge chain including a resistor, is additionally equipped with a thyristor and winding pulse transformer, and an additional thyristor is connected in series with the resistor of the discharge circuit, and A complementary winding is connected in opposite to the secondary windings and connected via a diode to the cathode and the control electrode of the additional thyristor.

The drawing shows a circuit of a pulse shaper for controlling thyristors.

The pulse shaper for controlling thyristors contains a series-connected auxiliary thyristor 1, an output pulse transformer 2 and a storage capacitor 3. The secondary windings of the output pulse transformer are connected via diodes 4 to cathodes and control electrodes of power thyristors, which are not shown in the drawing. The storage capacitor is shunted by a discharge circuit including a series-connected resistor 5 and a thyristor 6. The control electrode of the thyristor 6 is connected via a diode to an additional winding 7 made on the output pulse transformer.

The shaper works as follows.

When the auxiliary thyristor 1 is turned on, the storage capacitor 3 begins charging. The charging capacitor 3 charging current, flowing through the primary winding of the output pulse transformer 2, generates control pulses. When the auxiliary thyristor 1 is turned off, the charge of the storage capacitor 3 is stopped, the thyristor 6 is unlocked by the reverse current discharge of the output pulse transformer 2. The storage capacitor 3 is discharged through the discharges into the chain. After the end of the discharge of the storage capacitor 3, the driver is ready to generate the next pulse.

Introduction to the discharge circuit of the thyristor and the execution of the output pulse transformer with an additional winding, which is connected through the diode to the control electrode of the thyristor, favorably distinguishes the proposed driver from the known one. The reliability of the circuit increases, since the breakdown of work is completely eliminated due to the fact that there is no current in the discharge circuit at the time of operation of the auxiliary thyristor. Expansion of the frequency range of the driver by reducing the discharge time of the storage capacitor allows you to increase the scope of application of the pulse shaper, eliminate the need to develop a number of driver, whose frequency range is close to the frequency range of the proposed driver. · The implementation of a pulse transformer with an additional winding to control the thyristor allows to simplify the design of the proposed former: there is no need to use complex thyristor control circuits.

Claims (1)

Claim A pulse shaper for controlling thyristors containing a series-connected auxiliary thyristor, an output pulse transformer, the secondary windings of which through diodes are connected to cathodes and control electrodes of power thyristors, and a storage capacitor, which is shunted by a discharge chain and includes a resistor, characterized in that shaper and expansion of the frequency range of operation, the shaper is additionally equipped with a thyristor and a winding pulsed trap An additional thyristor is connected in series with the resistor of the discharge circuit, and an additional winding is connected opposite to the secondary windings and connected via a diode to the cathode and the control electrode of the additional thyristor.