RU107003U1 - TYRISTOR DRIVER - Google Patents

Abstract

 A thyristor driver, containing galvanically isolated power and control circuits and a current pulse shaper to turn on the thyristor, characterized in that it is powered by a pulse alternating voltage generator, the electrical isolation in it is provided by a transformer and an optocoupler or optical receiver of a control pulse of any duration, the amplitude of the afterburning current pulse is limited by the stabilizer in the base and resistor in the emitter circuits of the transistor, and the holding current is limited by the reactor connected between the second hydrochloric winding of the transformer and rectifier.

Description

The utility model relates to electrical engineering, in particular, to converting technology, and can be used to control the thyristor.

There are known requirements for the optimal shape of the current pulse: a rapid rise in current to a large amplitude and maintaining it for a short time (afterburner pulse) to turn the thyristor on, and then a long current of small magnitude (holding current) to keep the thyristor on, which is necessary when inductive active load.

Known driver circuits [1], [2] Fig. 1, in which the primary winding of the transformer is included in the collector circuit of the output stage, the secondary winding of the transformer is connected to the control electrode and to the cathode of the thyristor, and the current limiting resistor is connected in series with the primary or secondary winding.

The disadvantages of such schemes are: limiting the duration of the current pulse by saturation of the transformer core, a linear dependence of the current on the voltage at the control electrode, the power dissipated by the resistor, a decrease in the rate of rise of current by the inductance of the transformer windings.

Objectives of the utility model: to eliminate the limitation of the pulse duration, while ensuring the electrical isolation of the control system from the thyristor, reduce the dependence of the current on the voltage at the load, reduce energy loss, increase the rate of rise of the current, and obtain the optimal shape of the current pulse.

Figure 2 presents a diagram of the proposed driver.

The driver contains a pulse alternating voltage generator 1, a transformer 2, a reactor 3, a rectifier bridge 4, a capacitor 5, an optocoupler or an optical receiver 6, resistors 7 ... 10, a resistor 11, a transistor 12.

The driver works as follows. In the initial mode, the transistor 12 and the thyristor 13 are locked, the resistors 8 and 10 increase the noise immunity of this state. The generator 1 supplies to the primary winding of the transformer an alternating voltage of a rectangular shape. The rectifier 4 charges the capacitor 5 to the amplitude voltage of the secondary winding of the transformer. When a control pulse is applied to the photodetector 6, the current flowing through the resistor 7 creates a trigger voltage limited by the stabilizer 11 on the basis of the transistor 12. Thanks to the resistor 9 in the emitter, the collector current of the transistor 12 is practically independent of the voltage on the thyristor control electrode, an afterburner current pulse is formed whose slew rate is not limited to inductive elements. As the capacitor 5 discharges, the current decreases and begins to be limited by the reactor 3 included in the alternating current circuit, and a holding current is formed, the duration of which is determined only by the control pulse. The current limitation by the reactor does not lead to thermal energy losses, and the series connection of the inductive reactance of the reactor and the active resistance of the load over a wide range reduces the dependence of current on voltage.

The shape of the current pulse is shown in Fig.3. The dependence of the amplitude of the afterburner pulse and the holding current on the voltage shown in Fig.4.

Thus, the proposed driver circuit makes it possible to eliminate the limitation of the pulse duration, while ensuring the electrical isolation of the control system from the thyristor, reduce the dependence of the current on the voltage at the load, reduce energy loss, increase the slew rate of the current, and obtain the optimal shape of the current pulse.

Information sources:

1. Recommendations for the use of drivers for phase control thyristors. Technical Information ABB Switzerland Ltd Semiconductors http: /www.fmccrustel.ru/cat_index.php? Cid = 206

2. Isolated module for triggering thyristors IMZ 4 (thyristor driver) http://download.qrz.ru/pub/hamradio/schemes/misc/imz4.pdf

Claims (1)

A thyristor driver containing galvanically isolated power and control circuits and a current pulse generator to turn on the thyristor, characterized in that it is powered by a pulse alternating voltage generator, the electrical isolation in it is provided by a transformer and an optocoupler or optical receiver of a control pulse of any duration, the amplitude of the afterburning current pulse is limited by the stabilizer in the base and resistor in the emitter circuits of the transistor, and the holding current is limited by the reactor connected between the second hydrochloric winding of the transformer and rectifier.