JPS6010123Y2 - Arc-extinguishing circuit of self-extinguishing switching element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an arc extinguishing circuit for a switching device, and more particularly to an arc extinguishing circuit for a self-extinguishing switching device.

Generally, switching elements used in electrical circuits are protection circuits that protect against overvoltages and overvoltages that attack from the outside and from overcurrents and overvoltages caused by wiring impedance in the circuit due to self-on and off actions. is attached.

Therefore, if the original function of the circuit elements in this protection circuit is used to generate the extinguishing signal of the switching element,
The circuit arrangement itself is also simplified, which is very advantageous.

The present invention has been made in view of the above points, and its purpose is not only to provide protection characteristics for switching elements, especially self-extinguishing switching elements, but also to improve the performance of the self-extinguishing switching elements. An object of the present invention is to provide an arc extinguishing circuit capable of extinguishing an arc.

An arc extinguishing circuit for a self-extinguishing switching element according to an embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 shows an arc extinguishing circuit according to this embodiment, in which 1 is a gate turn-off thyristor which is a self-extinguishing switching element, and has an anode electrode which is a first main electrode and a cathode electrode which is a second main electrode. and a gate electrode which is a control electrode.

A capacitor 2 and a resistor 3 are originally used for overvoltage protection of switching elements, and these capacitor 2 and resistor 3 are used as a so-called snubber circuit.

In this embodiment, a diode lower 4, which is an electric valve, is connected in series through a resistor 5 to a snubber circuit consisting of a capacitor 2 and a resistor 3 connected in series.

The anode electrode of the diode 4, which is an electric valve, is connected to the anode electrode of the gate turn-off thyristor 1.

A diode 4, a resistor 5, and a capacitor 2 are connected between the anode electrode and the cathode electrode of this gate turn-off thyristor 1.
and a resistor 3 are connected in parallel to form a so-called charging loop.

A collector electrode 6C of a control switch element, such as a transistor 6, is connected to the connection point J□ between the resistor 5 and the capacitor 2, and its emitter electrode 6e is connected to the cathode electrode of the gate turn-off thyristor 1.

Reference numeral 7 denotes a control signal generating circuit for controlling the transistor 6 to turn on and off.

A diode 8 is connected between the connection point 2 of the capacitor 2 and the resistor 3 and the gate electrode of the gate turn-off thyristor 1 so that its cathode electrode is on the connection point J2 side. A diode 9 and a reverse bias element such as a constant voltage diode 10 are connected in series between the cathode electrodes.

capacitor 2, transistor 6, diode 9 and 8
A discharge loop of the capacitor 2 is formed by this.

In the above EtfdR, gate turn-off thyristor 1
A voltage with the polarity shown is applied between the anode electrode and the cathode electrode of the capacitor 2, and when the gate turn-off thyristor 1 is off and the transistor 6 is off, the capacitor 2 is charged with the polarity shown through the diode 4 and the resistor 5. Ru.

The gate turn-off thyristor 1 is made conductive by an ignition circuit (not shown), and even if the gate turn-off thyristor 1 is conductive, the transistor 6
If is off, the charge in the capacitor 2 will not be discharged by the diode 4.

Therefore, when the gate turn-off thyristor 1 is in the conductive state, when an on signal is supplied from the control signal generation circuit 7 to the base electrode 6b of the transistor 6, the transistor 6 becomes conductive.

When the transistor 6 is turned on, the charge of the capacitor 2 is transferred to the collector electrode and emitter electrode of the transistor 6, the constant voltage diode 10, the diode 9, and the diode 8.
The gate turn-off thyristor 1 is reverse biased and becomes non-conductive.

Furthermore, if an overvoltage is applied for some reason while the gate turn-off thyristor 1 is on, the diode 4,
Snubber consisting of resistor 5, capacitor 2 and resistor 3
The overvoltage is absorbed through the circuit and the gate turn-off thyristor 1 is protected.

Curve 1 in Figure 2 shows the time T-gate current characteristics of the gate turn-off thyristor 1, 11 is the ON signal current supplied from an ignition circuit (not shown), and 1° is an on-signal current supplied from an ignition circuit (not shown). The holding current supplied and the 13 off signal current are shown.

Therefore, in this embodiment, by turning on the transistor 6 shown in FIG. 1, the electric charge in the capacitor 2 is discharged, and an off signal current as shown in the curve 13 in FIG. It is something.

The holding current shown by the curve 1° in FIG. 2 is supplied to prevent the gate turn-off thyristor 1 from turning off due to the influence of an inductive load.

As explained above, the present invention forms a charging loop by connecting a snubber circuit consisting of a capacitor and a resistor in parallel via an electric valve to protect a self-extinguishing switching element from overvoltage and overcurrent. A discharge loop is attached to this charging loop to discharge the charge in the charging loop, and the switching element is arc-extinguished by this discharge current.

Therefore, according to the present invention, the switching element can be reliably extinguished with a simple circuit configuration, and the charging loop can also provide surge protection, providing a high performance and convenient arc extinguishing circuit.

[Brief explanation of the drawing]

FIG. 1 is an electrical wiring diagram of an arc extinguishing circuit of a self-extinguishing switching element according to an embodiment of the present invention, and FIG. 2 is a characteristic diagram thereof. 1... Self-extinguishing switching element such as gate turn-off switch, 2... Capacitor, 3.5... Resistor, 4... Electric valve. Diode, 6... Control switching element forming a discharge circuit, such as transistor, 7...
・Control signal generation circuit, 8, 9...diode,
10... Constant voltage diode.

Claims (1)

[Scope of utility model registration request] an electric valve connected to a first main electrode of a self-arc-extinguishing switching element having a first main electrode, a second main electrode, and a control electrode so as to be in a forward direction with the self-arc-extinguishing switching element; a charging loop comprising a capacitor connected in series to the electric valve, a snubber circuit having a resistor connected between the capacitor and the second main electrode, a connection point between the electric valve and the capacitor, and a control switching element connected between the second main electrodes in parallel with the snubber circuit; a reverse bias element connected between the second main electrode and the control electrode; and a reverse bias element connected between the second main electrode and the control electrode; a discharge loop comprising a diode connected between a connection point of a bias element and a connection point of the capacitor and the resistor so that the anode is on the control electrode side; and a control signal for controlling on/off a control switching element of the discharge loop. 1. An arc-extinguishing circuit for a self-extinguishing switching element, characterized in that the arc-extinguishing circuit comprises a generator circuit.