RU2641661C2 - Thyristor driver for high-voltage converters - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: driver comprises: a power source (1); a power control unit (2); an optical radiator (3); a logic unit (4); a thermal protection unit (5); a thyristor voltage control unit (6); a thyristor control signal control unit (7); an optical receiver (8); a delay unit (9); an amplifier (10). The driver is powered by a current transforme, made on a ferrite ring with a secondary winding wound on it. The ferrite ring is put on the insulating tube and filled with a compound. The primary winding of the current transformer is the wire of a high-frequency (50-kilohertz) current loop, passing successively through the current transformers of the other converter drivers. The secondary winding of the current transformer T is connected to the power source (1). The power source (1) is based on a diode bridge rectifier and a parallel voltage regulator. Capacitors are provided at the output of the power source to filter the stabilized voltage. The driver's operation consists in generating a thyristor control current pulse by the input optical signal, controlling thyristor voltage, and protecting the thyristor from overheating.

EFFECT: power source supplies the amplifier and the rest elements of the driver with stabilized voltages.

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Description

This invention relates to a conversion technique and can be used to control thyristors, including in high-voltage converters with a series connection of thyristors.

A known driver for controlling thyristors and thyristor modules [1], the installation of which is aimed at reducing the inductance of the wires connecting the driver to the thyristor, is provided close to the thyristor (including the cooler), and its power is supplied by a constant stabilized voltage received from the AC voltage 40 kHz transformed through an isolation transformer and then rectified. The driver provides control of a constant stabilized supply voltage using a comparator, and a control signal is transmitted to the control system through an optical emitter via an optical fiber cable. The control current is switched on by a light signal transmitted from the control system via a fiber optic cable to the driver optical receiver. The frequency and duration of the light signals is set by the control system.

Powerful high-voltage converters use a series connection of thyristors (high-voltage thyristor valves).

To control series-connected thyristors in high-voltage converters, simultaneous arrival of pulses with a steep front of the rise of the control current of at least 10 A / μs, as well as high noise immunity of the control circuits are required. Also important is the issue of protecting the thyristors of the valve from an avalanche-like failure of them in case of failure of one or more of them.

The disadvantage of the driver [1] is the lack of monitoring the state of health of the thyristor, monitoring the arrival of a control pulse to the driver, monitoring the passage of the pulse to the driver output, limiting the isolation voltage across the power circuit due to the location of the power transformer on the driver board.

A thyristor driver is proposed for controlling a thyristor connected in series with other thyristors in the high-voltage valves of the converters, allowing its installation near series-connected thyristors (including coolers on the cathode side of the thyristors), powered by a current transformer with high voltage insulation, containing a power source , a stabilized power supply control unit, the outputs of which are connected to an LED indicator, an optical emitter, an optical receiver, silitel, characterized in that it further comprises a thermal protection unit, a thyristor voltage control unit, a thyristor control signal control unit, a delay unit, a logic unit, LED indicators, wherein: the output of the thermal protection unit is connected to the input of the logic unit, and the input to the temperature sensor, mounted on the cooler of the cathode side of the thyristor, the output of the thyristor voltage control unit is connected to the other input of the logic unit, and the input is connected to the thyristor resistive voltage divider, the output of the control signal control unit to the thyristor connected to the third input of the logic node, and the input to the output of the amplifier, the output of the optical receiver is connected to the fourth input of the logic node and to the input of the delay node, the output of which is connected to the amplifier input, the outputs of the stabilized voltage control node are connected to the fifth and sixth inputs of the logic node, the outputs the logic node is connected to an optical emitter and LED indicators.

Functional diagram of the driver is shown in FIG. one.

The driver includes: power supply 1; power control unit 2; optical emitter 3; logic node 4; thermal protection unit 5; the node for monitoring the voltage on the thyristor 6; control signal control unit on thyristor 7; optical receiver 8; delay unit 9; amplifier 10.

The driver is powered by a current transformer made on a ferrite ring, with a secondary winding wound on it. The ferrite ring is put on the insulating tube and is filled with a compound. The primary winding of the current transformer is a wire of a high-frequency (50-kilohertz) current loop passing sequentially through the current transformers of the remaining converter drivers.

The secondary winding of the current transformer T is connected to a power source 1.

The power source 1 is based on a diode bridge rectifier and a parallel voltage stabilizer. Capacitors are provided at the output of the power source to filter the stabilized voltage.

The power supply provides stabilized voltages to the power of the amplifier 10 and other driver elements.

The driver's job is to generate a thyristor control current pulse by the input optical signal, control the voltage on the thyristor, protect the thyristor from overheating.

During normal operation of the converter, reverse voltage is present on the thyristor, and the heating temperature of the thyristor is less than the permissible value. At the outputs of the node of the voltage control on the thyristor 6, the thermal protection unit 5 and the power control unit 2 there is a level of a logical unit.

In the absence of a control pulse at the output of the optical receiver 8 and at the output of the control unit of the control signal at thyristor 7, there is also a logic unit level.

To open the thyristor from the control system of the converter (SU), an optical pulse of a given duration is fed to the optical receiver 8. Optical receiver 8 has a logic zero level at the output of the optical receiver 8 during the duration of the optical signal. This signal is fed to logic node 4 and delay node 9. During normal operation, when an optical pulse arrives, the output of logic node 4 receives a signal to optical emitter 3, which generates a response optical signal transmitted via an optical cable to the control system.

Logical zero from the output of the optical receiver 8 through the delay node 9 (with a delay time of 5 μs) is supplied to the amplifier 10, which forms a control current pulse of the thyristor V.

During the control pulse at the output of the control signal control node on the thyristor 7 there is a logic zero level.

At the end of the optical pulse, the driver circuit returns to its original state.

In the absence of reverse voltage at the thyristor (due to breakdown of the thyristor or other malfunctions), a logic zero level appears at the output of the voltage monitoring node at the thyristor 6, which blocks the signal generation to turn on the optical emitter 3 in the logic node 4.

In this case, when the next optical control pulse arrives from the control unit from the driver from the driver board, the response optical signal is not output to the control unit. After the waiting time for the response optical signal (2 μs), the control unit disconnects the optical control pulses from all thyristor driver drivers before the delay time (5 μs) of the delay unit 9 expires and gives a signal for emergency power off of the converter. Thus, the converter is protected from operation when the thyristor is faulty, which eliminates the further spread of the accident.

If the thyristor is heated above the permissible value at the output of the thermal protection unit 5, a logic zero level appears, which blocks the formation of a signal for switching on the optical emitter 3 in the logic unit 4.

In this case, the protection is tripped and the converter is switched off similarly to the case described above in the absence of reverse voltage across the thyristor.

In the event of a deviation of the driver's supply voltage more than the permissible values at the output of the power control unit 2, a logic zero level appears, which blocks the generation of a signal to turn on the optical emitter 3 in the logic node 4.

In this case, the protection is triggered similarly to the case described above in the absence of reverse voltage on the thyristor.

The logic node 4 provides control of the passage of the control pulse to the driver output by controlling the coincidence of the signals at the outputs of the optical receiver 8 and the control node of the control signal at the thyristor 7. If there is an optical control pulse at the output of the optical receiver 8, there is a logic zero level. During normal operation, 5 μs after the appearance of a logical zero at the output of the optical receiver 8, a logical zero level should appear at the output of the control signal control unit on the thyristor 7.

In the absence of a control current pulse at the output of the amplifier 10 due to its malfunction or breakdown of the thyristor V at the output of the control signal control unit at the thyristor 7 there is a level of a logical unit. The logic node 4 after a delay time of 100 μs turns off the optical emitter 3. The response optical signal is turned off. The control system turns off the optical control pulses from all thyristor drivers of the converter and gives a signal for emergency shutdown of the power supply of the converter.

The driver provides LED alarm:

- about normal driver power - POWER indicator;

- about the presence of reverse voltage on the thyristor - indicator Utir;

- about triggering of protection against thyristor overheating - OVERHEAT indicator.

The OVERHEAT indicator is turned on by the RS-trigger in the logic node 4 when the thyristor overheats. To reset the trigger to its original state after the protection is activated, it is necessary to turn off and turn on the driver power. At the moment after the driver’s power supply, the power control unit 2 generates a pulse that sets the RS-trigger in the logic unit 4 to its initial state.

Thus, the proposed driver provides control and protection of series-connected thyristors in the high-voltage valves of the converters from an avalanche-like failure of one or several of them by controlling the passage of the optical control signal to the driver from the control system, controlling the heating temperature of the thyristor, and monitoring the voltage on the thyristor, issuing a confirming optical signal to the control system about the operating state of the driver and the thyristor, a fixed delay in the supply of a control pulse on the thyristor, monitoring the passage of the pulse to the control terminals of the thyristor.

Bibliography

1. Driver DRT11-5-6FP1K-1 DZHITS.687253.434.

Claims (1)

A thyristor driver for high-voltage converters containing a power source, a driver power supply voltage monitoring unit, an optical emitter, an optical detector, an amplifier, characterized in that the driver also includes a thermal protection unit, a voltage control unit on the thyristor, a control signal control unit on the thyristor, a delay unit, a unit logic, LED indicators, while the output of the thermal protection unit is connected to the input of the logic unit, and the input is connected to a temperature sensor installed on the cathode side cooler of the thyristor, the output of the control unit For voltage on the thyristor, it is connected to the second input of the thyristor node, and the input is connected to the resistive voltage divider of the thyristor, the output of the control signal control node on the thyristor is connected to the third input of the logic node, and the input is to the output of the amplifier, the output of the optical receiver is connected to the fourth input of the logic node, and with the input of the delay node, the output of which is connected to the input of the amplifier, the outputs of the stabilized voltage control node are connected to the fifth and sixth inputs of the logic node, the outputs of the logic node are connected to the optical emitter and LED indicator ami.

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