JP2614290B2 - GTO thyristor gate control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a gate control device of a GTO thyristor.

(Prior art) In a GTO thyristor gate control device which receives a signal from a gate control signal generating means for instructing a gate control timing of the GTO thyristor and generates a gate pulse current required for the turn-on / turn-off operation of the GTO thyristor In recent years, a system for transmitting a signal from a gate control signal generating means to a gate control device through an optical fiber or the like and generating a gate pulse has been widely used in recent years.

In such a GTO thyristor gate control device, a gate signal amplifying means for amplifying a signal transmitted from a power supply and an optical fiber for generating a gate pulse and converting the signal into a gate pulse is provided. Requires a power supply to operate.

FIG. 2 shows a conventional example of such a GTO thyristor gate control device.
Transformer 1 for AC power supply, rectifier circuits 2 and 3 for rectifying the secondary side output of this transformer 1, capacitors 4 and 5 provided in these rectifier circuits 2 and 3, on-gate drive switching transistor 6, off-gate drive switching It comprises a transistor 7, a resistor 8, a GTO thyristor 9 on / off controlled by the on-gate drive switching transistor 6 and the off-gate drive switching transistor 7.

The GTO thyristor drive main circuit has a gate signal amplifier 10 that supplies an inversion operation base current to each of the on-gate drive switching transistor 6 and the off-gate drive switching transistor 7. Photoelectric conversion module 12, limiting resistors 13, 14, base resistors 15, 16, signal amplifying transistors 17, 18, collector resistors 19, 20, and stabilized power supply 2 common to these circuit elements
Has one. The stabilized power supply 21 is connected so as to receive power from both ends of the capacitor 4 of the main circuit.

Each photoelectric conversion module 11, 1 of the gate signal amplifier 10
The on-gate signal and off-gate signal given to each of the two are transmitted from the gate control signal generator 22 via the optical fiber 23.

In such a conventional GTO thyristor gate control device, the gate control signal from the gate control signal generation unit 22 is input to the photoelectric conversion modules 11 and 12 of the gate signal amplification unit 10 through the optical fiber 23, where the on-gate Each of the signal and the off-gate signal is converted from an optical signal to an electric signal and output.

As for the on-gate signal, the output of the on-gate signal photoelectric conversion module 11 becomes “H” level at the time of the “L” level, and the current from the stabilized power supply 21 is supplied to the base current of the on-gate signal amplification transistor 17 via the resistors 13 and 15. Then, the signal amplification transistor 17 is turned on, the base of the on-gate drive switching transistor 6 is set to “H” via the collector resistor 19, the switching transistor 6 is turned on to turn on the GTO thyristor 9, and the GTO thyristor 9 is turned on. An on-gate pulse current is supplied to the thyristor 9.

Similarly, with respect to the off-gate signal, the output of the off-gate signal photoelectric conversion module 12 becomes “H” level at the “L” level, the off-gate signal amplification transistor 18 is turned on, the off-gate drive switching transistor 7 is turned on, and the GTO thyristor 9 is turned on. Is turned off, and an off-gate pulse current is supplied from the capacitor 5 to the GTO thyristor 9.

(Problems to be Solved by the Invention) However, in such a conventional gate control device of a GTO thyristor, the signal amplifier 10 needs a power supply for operating itself, but the voltage of this power supply is established. Otherwise, the normal operation of the signal amplifier 10 cannot be guaranteed. There is also a problem that the signal amplifier 10 outputs a base current when the gate control signal generator 22 does not output a gate command.

Further, the anode A and the cathode K of the GTO thyristor 9
If a voltage is applied between the gate control device and the capacitor 4 or 5 of the gate drive power supply, a voltage remains on the capacitor 4 or 5 of the gate drive power supply unit. And the thyristor 9 is erroneously fired.

Furthermore, each circuit element of the on-gate signal amplification system photoelectric conversion module 11, the on-gate signal amplification transistor 17 and the switching transistor 6, and the off-gate amplification system photoelectric conversion module 12, the off-gate signal amplification transistor 18 and the switching transistor 7, Since the ground potential of each circuit element is common, mutual interference occurs during the switching operation of each other, and there is a problem that an erroneous gate control current may be supplied to the GTO thyristor 9.

The present invention has been made in view of such a conventional problem, and does not generate an erroneous gate control current in a transient state at the time of turning on / off a power supply. It is an object of the present invention to provide a gate control device for a GTO thyristor free from interference.

[Means for Solving the Problems] A gate control device for a GTO thyristor according to the present invention includes a gate control signal generating means for generating an on-gate signal and an off-gate signal for the GTO thyristor, and an on-gate from the gate control signal generating means. Means for individually inputting and amplifying the signal and the off-gate signal, wherein the on-gate signal amplifying means and the off-gate amplifying means having different grounds from each other, the power supply of each of the on-gate signal amplifying means and the off-gate signal amplifying means, On-gate drive switching means and off-gate drive switching means for performing a switching operation by each output of the on-gate signal amplification means and off-gate signal amplification means to perform turn-on and turn-off control of the GTO thyristor; an output terminal of the on-gate signal amplification means; Constant voltage diodes which are provided between the inverting gate of the gate driving switching means and between the output terminal of the off-gate signal amplifying means and the inverting gate of the off-gate driving switching means, and which conduct when a potential of a certain value or more is applied. It is provided with.

(Operation) In the gate control device of the GTO thyristor of the present invention, the power supply and the ground of the on-gate signal amplifying means and the off-gate signal amplifying means are separated from each other, whereby mutual interference can be prevented.

In addition, a constant voltage diode is provided between the on-gate signal output terminal of the on-gate signal amplifying means and the inverting gate of the on-gate driving switching means, and between the off-gate signal output terminal of the off-gate signal amplifying means and the inverting gate of the off-gate driving switching means. By inserting, the on-gate drive switching means and the off-gate drive switching means are operated only when the power supply is sufficiently established. In this case, the switching means of the present invention cannot perform the reversing operation, thereby preventing erroneous firing of the GTO thyristor.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a circuit diagram of one embodiment of the present invention, and the same reference numerals are given to the same components as those used in FIG. 2 of a conventional example.

In this embodiment, the on-gate driving switching transistor 6 is provided between the cathode K of the GTO thyristor 9 and one terminal of the capacitor 4, and the off-gate driving switching transistor 7 is connected between the anode A of the GTO thyristor 9 and one terminal of the capacitor 5. It is provided between them.

Also, the power for the on-gate signal system in the gate control signal amplifier 10 is taken from both ends of the capacitor 4 on the on-gate drive power supply side, and separately from this, the power for the off-gate signal system is taken from both ends of the capacitor 5 on the off-gate drive power supply side. Have been.

Furthermore, the stabilizing power supply is also separated into an on-gate signal system and an off-gate signal system, separated from the on-gate signal system stabilizing power supply 21, and a separate stabilizing power supply 24 for the off-gate signal system is provided separately.
Electric power can be individually supplied to 11 and the off-gate signal photoelectric conversion module 12.

Further, an on-gate signal amplification transistor 17 is used.
In addition to the npn type, a zener diode 25 is provided between its collector and the base as the inverting gate of the on-gate drive switching transistor 6, and similarly, the collector of the npn-type off-gate signal amplification transistor 18 and the off-gate drive switching transistor 7 Zener diode 26 is provided between the base and the base.

The operation of the GTO thyristor gate control device having the above configuration will be described below.

The rectifier circuit 2 and the capacitor 4 form an on-gate drive current from the AC power supply via the transformer 1, and the rectifier circuit 3 and the capacitor 5 form an off-gate drive power supply.

When the on-gate signal is not given from the gate control signal generator 22 through the optical fiber 23, the output of the on-gate signal photoelectric conversion module 11 is at “H” level, and the base current is supplied to the on-gate signal amplification via the resistors 13 and 15. The transistor 17 is supplied to the transistor 17, and the transistor 14 is turned on. As a result, the collector potential of the transistor 17 becomes "L".
Level, no current is applied to the base of the on-gate drive switching transistor 6 via the Zener diode 25, and this switching transistor 6 is placed in the off state.

Similarly, when the off-gate signal is not supplied from the gate control signal generator 22 to the off-gate signal photoelectric conversion module 12, the output of the photoelectric conversion module 12 is at the “H” level, and the off-gate signal amplification is performed via the resistors 14 and 16. Current is supplied to the base of the off-gate driving switching transistor 7 via the Zener diode 26, and the current is not supplied to the base of the switching transistor 7. The transistor 7 is also turned off.

Therefore, now, when the on-gate signal from the gate control signal generation unit 22 becomes “H” level, the transistor of the on-gate signal photoelectric conversion module 11 is turned on and its output is inverted to “L” level. The base current of the transistor 17 for amplifying the on-gate signal to which the base current was supplied via 15
11, the transistor 17 is inverted, and a current is supplied to the base of the on-gate drive switching transistor 6 via the resistor 19 and the zener diode 25. The on-gate drive current limited by the resistor 8 is supplied to the GTO thyristor 9 to turn on the GTO thyristor 9.

Similarly, when the off-gate signal from the gate control signal generation unit 22 goes to “H” level, the transistor of the off-gate signal photoelectric conversion module 12 is turned on and its output is inverted to “L” level, and the off-gate signal is amplified. The base current of the transistor 18 is cut off, the transistor 18 is inverted and turned off, the collector potential rises, and the resistance 20
A current is applied to the base of the off-gate drive switching transistor 7 via the Zener diode 26, and the base is turned on by inverting the current. An off-gate drive current is supplied from the off-gate drive power supply to the GTO thyristor 9, and the GTO thyristor 9 is turned off.

The GTO thyristor 9 is composed of the switching transistors 6 and 7
The turn-on and turn-off are repeated by the alternate on-operation of, and pulse control of the conduction current is performed.

Here, the Zener voltages of the Zener diodes 25 and 26 are set as follows.

The sum of the minimum voltage Vm ₁ that guarantees the operation of the gate signal photoelectric conversion modules 11 and 12 and the minimum drop voltage Vm ₂ of the stabilized power supplies 21 and 24, a value higher than Vm ₁ + Vm ₂ and both ends of the capacitors 4 and 5 The zener voltage is set to a voltage, that is, a value lower than the power supply voltage of the signal amplifier 10.

With this setting, the power supply voltage of the gate signal amplifying unit 10 becomes a halfway value when the power is turned on / off, and the output voltage of the stabilized power supplies 21 and 24 is changed to the gate signal photoelectric conversion module 11,
Even if the voltage drops below the guaranteed operation voltage of 12, the capacitor that becomes the base current source of the switching transistors 6 and 7 at this point
Since the voltages of 4, 5 are lower than the zener voltages of the zener diodes 25, 26, no base current is output to these switching transistors 6, 7.

When the on-gate drive switching transistor 6 is turned on, an on-gate drive current limited by the resistor 8 flows through the GTO thyristor 9 using the transformer 1, the rectifier circuit 2, and the capacitor 4 as power supplies. earth potential E ₁ of the on-gate driving power source varies with the voltage.

In the conventional example, the potential indicated by the ground potential E in Figure 2 corresponds to the ground potential E _1, if such, this ground potential E varies, and the ground potential ON gate signal amplification system with off-gate signal amplification system In this embodiment, the off-gate signal amplification transistor 18 may malfunction, but in this embodiment, the ground potential of the on-gate signal amplification system
Since E ₁ and the off-gate signal amplification system ground potential E ₂ of being separated at the free may interfere with each other.

[Effects of the Invention] As described above, according to the present invention, the power supply and the ground are separated between the on-gate signal amplification system and the off-gate signal amplification system, and the output of the on-gate signal amplification system and the inversion of the switching means of the on-gate power supply. A constant voltage diode is provided between the gate and between the output of the off-gate signal amplification system and the inverting gate of the switching means of the off-gate power supply, so that a constant voltage diode is provided between the on-gate signal amplification system and the off-gate signal amplification system. There is no mutual interference, and at the same time, when the power supply is turned on and off, a sufficient voltage rises at the inverting gate of the switching means even when the on-gate signal amplification transistor or the off-gate signal amplification transistor is turned on. Without switching, the switching means does not reverse, thus causing the switching means to malfunction There is no work, and GTO thyristor gate control can be performed accurately.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram of one embodiment of the present invention, and FIG. 2 is a circuit block diagram of a conventional example. 1 ... Transformer, 2,3 ... Rectifier circuit 4,5 ... Capacitor 6 ... On-gate driving switching transistor 6 ... Off-gate driving switching transistor 9 ... GTO thyristor 10 ... Gate control signal amplifier 11,12 ... Photoelectric conversion module 17 Transistor for on-gate signal amplification 18 Transistor for off-gate signal amplification 21 Stabilized power supply 22 Gate control signal generator 23 Optical fiber 24 Stabilized power supply 25, 26 Zener diode

Claims (1)

(57) [Claims] 1. A gate control signal generating means for generating an on-gate signal and an off-gate signal for a GTO thyristor, and means for separately inputting and amplifying the on-gate signal and the off-gate signal from the gate control signal generating means, wherein the grounds are mutually connected. A GTO thyristor which performs a switching operation by means of different on-gate signal amplifying means and off-gate signal amplifying means, power supplies of these on-gate signal amplifying means and off-gate signal amplifying means, and outputs of the on-gate signal amplifying means and off-gate signal amplifying means. An on-gate drive switching means and an off-gate drive switching means for performing turn-on and turn-off control of the on-gate signal amplifying means between the output terminal of the on-gate signal amplifying means and the inverting gate of the on-gate drive switching means; Each provided, the gate control unit of the GTO thyristor comprising a constant voltage diode conductive when the potential is applied more than a predetermined value between the output terminal and the inverting gate of the off gate drive switching means.