JP2013041782A - Arc extinguishing device and switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an arc extinguishing device capable of simplifying a special circuit configuration required for operations of a semiconductor switch element for extinguishing arcs.SOLUTION: An arc extinguishing device extinguishes arcs generated at an opening operation of a mechanical switch. The mechanical switch has a series circuit for connecting an electric contact point 21 and an electric contact point 22 in series. An IGBT (a semiconductor switch element) 40 is connected in parallel to the series circuit. A gate terminal of the IGBT 40 is connected to a common connector between the electric contact point 21 and the electric contact point 22.

Description

  The present invention relates to an arc extinguishing device that eliminates an arc generated in a mechanical switch, and a switch such as a circuit breaker, a leakage breaker, and an electromagnetic contactor including the arc extinguishing device.

Conventionally, for example, a conventional technique as shown in FIG. 13 is known as a technique for opening and closing a circuit. In this prior art, as shown in the figure, a DC power source 54 is connected to a load 55 through a mechanical electrical contact 52 and an auxiliary contact 53 connected in series, and an IGBT (insulated gate bipolar transistor) is connected in parallel to the electrical contact 52. ) 51 is connected.
In the conventional technology having such a configuration, when supplying a current from the DC power supply 54 to the load 55, both the electrical contact 52 and the auxiliary contact 53 are closed, and the IGBT 51 is turned off. On the other hand, in order to cut off the supply of current to the load 55, the IGBT 51 is first turned on, and the electrical contact 52 is subsequently opened. At this time, the current flowing in the electrical contact 52 is commutated to the IGBT 51 side simultaneously with the opening of the electrical contact 52. Thereafter, by turning off the IGBT 51, the current flowing in the IGBT 51 is also cut off.

As described above, the prior art shown in FIG. 13 has a shunt circuit including the IGBT 51 connected in parallel to the electrical contact 52, so that the current flowing through the electrical contact 52 side is quickly commutated to the IGBT 51 side, There is no arcing.
For this reason, an additional configuration for extinguishing the arc is unnecessary on the electrical contact 52 side, and the electrical contact 52 can be designed in consideration of a normal capacity. Further, the semiconductor switch element such as the IGBT 51 constituting the shunt circuit has an advantage that it can be energized only for a short time necessary for interrupting the current and there is no temperature rise.

  By the way, as a technique similar to the prior art shown in FIG. 13, for example, an arc erasing apparatus between contacts of a mechanical switch shown in Patent Document 1 is known. The erasing device includes a mechanical switch, a semiconductor switch connected in parallel to the mechanical switch to erase an arc generated in the mechanical switch, a control circuit for controlling on / off of the semiconductor switch, and the like.

Japanese Patent Laid-Open No. 8-106839

  However, the prior art shown in FIG. 13 requires a control circuit for controlling the operation of the semiconductor switch element such as the IGBT 51 and also has a structure for turning on and off the electrical contact 52 in synchronization with the on / off operation of the semiconductor switch element. Is required. In addition, the erasing apparatus described in Patent Document 1 needs to be provided with a control circuit that controls on / off of the semiconductor switch element, as in the related art shown in FIG.

  Therefore, the present invention has been made paying attention to the above-described problems, and provides an arc extinguishing device and the like that can simplify the circuit configuration necessary for the operation of the semiconductor switch element in order to eliminate the arc. For the purpose.

In order to achieve the above object, the present invention has the following configuration.
The present invention is an arc extinguishing device that erases an arc generated in a switch when a mechanical switch is opened, wherein a semiconductor switch element is connected in parallel to the switch, and the control terminal of the semiconductor switch element is connected An arc voltage generated by the switch was applied.
In the present invention, the mechanical switch includes a series circuit that connects a first electrical contact and a second electrical contact in series, and the semiconductor switch element is connected in parallel to the series circuit, and the semiconductor The control terminal of the switch element is connected to a common connection portion of the first electrical contact and the second electrical contact.

In the present invention, the mechanical switch includes a first fixed contact, a second fixed contact, and a movable contact that connects the first fixed contact and the second fixed contact. The semiconductor switch element is connected in parallel to the switch, and the control terminal of the semiconductor switch element is connected to the movable contact.
The present invention further includes a capacitor that holds the voltage of the control terminal of the semiconductor switch element.

  The present invention further includes a resistor for discharging the electric charge of the capacitor.

  In the present invention having such a configuration, when the mechanical switch is opened, the semiconductor switch element can be operated in synchronization with the opening operation, and a special control circuit or the like is not required. Simplification can be achieved.

It is a top view which shows the external appearance of 1st Embodiment which applied the arc-extinguishing apparatus of this invention to the circuit breaker for wiring. It is a circuit diagram which shows the circuit structure of 1st Embodiment. It is a figure at the time of an energization state in the circuit of 1st Embodiment. It is a figure at the time of the initial stage when the electrical contact opened in the circuit of 1st Embodiment. In the circuit of 1st Embodiment, it is a figure when the electric current of the main circuit is commutated to the semiconductor switch element side. It is a figure at the time of completion | finish of interruption | blocking in the circuit of 1st Embodiment. It is sectional drawing which shows the cross section of 2nd Embodiment which applied the arc-extinguishing apparatus of this invention to the electromagnetic contactor. It is a circuit diagram which shows the circuit structure of 2nd Embodiment. It is a figure at the time of an energization state in the circuit of 2nd Embodiment. It is a figure at the time of the initial stage when the electrical contact opened in the circuit of 2nd Embodiment. It is a figure when the electric current of the main circuit commutates to the semiconductor switch element side in the circuit of 2nd Embodiment. It is a figure at the time of completion | finish of interruption | blocking in the circuit of 2nd Embodiment. It is a figure explaining a prior art.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Configuration of the first embodiment)
FIG. 1 is a plan view showing an appearance of a first embodiment in which the arc extinguishing device of the present invention is applied to a circuit breaker for wiring.
As shown in FIG. 1, the wiring circuit breaker (circuit breaker) according to the first embodiment includes a two-pole wiring circuit breaker 1 and an arc extinguishing device 4.

The circuit breaker 1 for wiring is provided with terminals 11 to 14 for external connection as shown in FIG. 1, and two electrical contacts 21 and 22 constituting a mechanical (contact type) switch shown in FIG. It is provided inside. The electrical contacts 21 and 22 can be simultaneously closed (ON) and opened (OFF) by operating a manual lever.
Both ends of the electrical contact 21 are connected to the terminal 11 and the terminal 12 as shown in FIG. Further, both ends of the electrical contact 22 are connected to the terminal 13 and the terminal 14. Furthermore, as shown in FIG. 1, the terminal 12 and the terminal 13 are electrically connected externally.

With such an electrical connection, as shown in FIG. 2, the electrical contact 21 and the electrical contact 22 are connected in series to form a mechanical switch, and one end of the electrical contact 21 is connected to the terminal 11. One end of the electrical contact 22 is connected to the terminal 14. Here, the arrows in FIG. 1 indicate the direction in which current flows in the connection shown in FIG.
The arc extinguishing device 4 erases an arc generated when the electrical contact 21 and the electrical contact 22 are opened, in synchronization (interlocking) with the opening operation. For this reason, as shown in FIG. 2, the arc extinguishing device 4 includes an IGBT 40 that is a semiconductor switch element, resistors 41 and 42, an overvoltage suppressing element (varistor) 43, and a capacitor 44.

The IGBT 40 is connected in parallel to a series circuit in which the electrical contacts 21 and 22 are connected in series. That is, the collector terminal of the IGBT 40 is connected to the terminal 11, and the emitter terminal of the IGBT 40 is connected to the terminal 14.
The resistors 41 and 42 are connected in series, and this series circuit is connected in parallel to the electrical contact 22 to form a voltage dividing circuit 45 that divides the arc voltage generated at the electrical contact 22. A voltage dividing terminal of the voltage dividing circuit 45 is connected to a gate terminal which is a control terminal of the IGBT 40.
An overvoltage suppressing element 43 that suppresses the gate terminal from an overvoltage is connected between the gate terminal and the emitter terminal of the IGBT 40. A capacitor 44 that holds the voltage of the gate terminal is connected between the gate terminal and the emitter terminal of the IGBT 40.

(Operation of the first embodiment)
Next, an operation example of the first embodiment will be described with reference to FIGS.
FIG. 3 is a diagram when the circuit of the first embodiment is in an energized state. The terminal 11 is connected to a power source (not shown), and a load (not shown) is connected to the terminal 14.
At this time, the electrical contacts 21 and 22 of the circuit breaker 1 are both closed, and the current a of the main circuit flows through the electrical contacts 21 and 22. Since the voltage generated between both terminals of the electrical contact 22 is approximately 0 [V], the gate voltage of the IGBT 40 is also 0 [V]. For this reason, IGBT40 will be in an OFF state.

FIG. 4 is a diagram at an initial stage in which all of the electrical contacts 21 and 22 are changed from a closed state to an open state in the circuit of the first embodiment.
At this time, the electrical contacts 21 and 22 of the circuit breaker 1 are both opened, and an arc as shown in FIG. Due to the generation of the arc, arc voltages are generated between the terminal 11 and the terminal 12 and between the terminal 13 and the terminal 14, respectively.

  The arc voltage is determined by the contact material of the electrical contacts 21 and 22 and the gap between the electrodes. If the gap between the electrodes is about 3 [mm], for example, the arc voltage has characteristics that depend substantially on the contact material. In this case, the arc voltage does not depend on the breaking current value, and a voltage of approximately 30 [V] is generated. Therefore, arc voltages generated between the terminal 11 and the terminal 12 and between the terminal 13 and the terminal 14 are about 30 [V], respectively.

Here, when the resistance values of the resistors 41 and 42 of the voltage dividing circuit 45 are set to the same value, the gate voltage of the IGBT 40 becomes 15 [V] which is ½ of the arc voltage. At this time, the capacitor 44 is charged by the gate voltage of the IGBT 40, and the charging voltage becomes 15 [V]. For this reason, the IGBT 40 is switched from the off state to the on state.
The capacitor 44 may use a parasitic capacitance between the gate and the emitter of the IGBT 40. In this case, the capacitor 44 is unnecessary.

FIG. 5 is a diagram when the current a flowing in the main circuit is commutated to the IGBT 40 side in the circuit of the first embodiment.
When the IGBT 40 is switched to the ON state, as shown in FIG. 5, the current a of the main circuit that has been flowing through the circuit breaker 1 for wiring is switched to the circuit on the IGBT 40 side. As a result of this commutation operation, the arcs generated at the electrical contacts 21 and 22 of the circuit breaker 1 are all extinguished. Then, the arc voltage applied to the gate of the IGBT 40 disappears. Accordingly, the electric charge charged in the capacitor 44 is discharged through the resistor 42.

FIG. 6 is a diagram at the time of completion of shutoff in the circuit of the first embodiment.
As the charge of the capacitor 44 is discharged and the voltage applied to the gate of the IGBT 40 decreases, the IGBT 40 switches from the on state to the off state. As a result, as shown in FIG. 6, the commutation operation of the current a of the main circuit is completed, and the current a of the main circuit is also completely cut off.
After the interruption by the IGBT 40 is completed, an auxiliary contact (not shown) arranged on the power supply side with respect to the terminal 11 of the wiring circuit breaker 1 is opened, thereby performing an electrical disconnection and a load connected to the terminal 14 ( (Not shown) and the power supply can be completely disconnected.

Here, the discharge rate (discharge time) of the charge of the capacitor 44 is determined by the time constant of the capacitor 44 and the discharge resistor 42. Therefore, by adjusting the time constant, it is possible to arbitrarily adjust or set the time from the extinction of the arc generated at the electrical contacts 21 and 22 until the current a of the main circuit is interrupted by turning off the IGBT 40. it can.
Further, since the time constant controls the time (time interval) from turning on the IGBT 40 to turning it off, the current decay time in the arc-extinguishing device 4 is controlled by selecting the time constant on the order of ms, for example. it can. As a result, control such as suppression of the surge voltage immediately after interruption is also possible.

As described above, in the first embodiment, when the electrical contacts 21 and 22 are opened, a part of the arc voltage generated at the electrical contact 22 is applied to the gate of the IGBT 40, thereby turning on the IGBT 40 and turning on the main circuit. The current was commutated to the IGBT 40 side to extinguish the arc. In addition, after the arc disappears, the charge of the capacitor 44 is discharged, and the IGBT 40 is turned off.
Therefore, according to the first embodiment, when the electrical contacts 21 and 22 are opened, there is no need for a special control circuit that turns on the IGBT 40 in synchronization with the opening operation and then turns it off. The arc generated at the electrical contact can be eliminated by a simple circuit.

(Configuration of Second Embodiment)
FIG. 7 is a cross-sectional view showing a cross section of a second embodiment in which the arc extinguishing device of the present invention is applied to an electromagnetic contactor.
As shown in FIG. 7, the electromagnetic contactor (switch) according to the second embodiment includes an electromagnetic contactor 3 having two contact points (two contacts) per pole and an arc extinguishing device 4. Yes.
As shown in FIG. 7, the electromagnetic contactor 3 includes an electrical contact 30 that constitutes a mechanical switch, terminals 31 and 32, and an electromagnet 33 that opens and closes the electrical contact 30. Built in.

The electrical contact 30 includes two fixed contacts 301 and 302 and one movable contact 303. As shown in FIG. 8, both ends of the movable contact 303 are electrically connected to the fixed contacts 301 and 302. The fixed contacts 301 and 302 are connected to the terminals 31 and 32, respectively.
As shown in FIG. 7, the electromagnet 33 includes a fixed iron core 332, a movable iron core 334, and a coil 336 wound around the fixed iron core 332, so that the movable iron core 334 can be moved by flowing a current through the coil 336. It has become. A movable contact 303 is connected to the movable iron core 334. Therefore, the movable contact 303 can be connected to the fixed contacts 301 and 302 by exciting the electromagnet 33, and the movable contact 303 can be separated from the fixed contacts 301 and 302 by releasing the excitation.

The arc extinguishing device 4 erases an arc generated when the electrical contact 30 is in an opening operation in synchronization (interlocking) with the opening operation. For this reason, as shown in FIG. 8, the arc extinguishing device 4 includes an IGBT 40 that is a semiconductor switch element, resistors 41 and 42, an overvoltage suppressing element 43, and a capacitor 44.
The IGBT 40 is connected to the electrical contact 30 in parallel. That is, the collector terminal of the IGBT 40 is connected to the terminal 31, and the emitter terminal of the IGBT 40 is connected to the terminal 32.

The resistors 41 and 42 are connected in series, and both ends of the series circuit are connected to the movable contact 303 and the fixed contact 302 of the electrical contact 30 to divide the arc voltage generated between the movable contact 303 and the fixed contact 302. A pressure circuit 45 is formed. A voltage dividing terminal of the voltage dividing circuit 45 is connected to a gate terminal which is a control terminal of the IGBT 40.
An overvoltage suppressing element 43 that suppresses the gate terminal from an overvoltage is connected between the gate terminal and the emitter terminal of the IGBT 40. A capacitor 44 that holds the voltage of the gate terminal is connected between the gate terminal and the emitter terminal of the IGBT 40.

(Operation of Second Embodiment)
Next, an operation example of the second embodiment will be described with reference to FIGS.
FIG. 9 is a diagram when the circuit of the second embodiment is in an energized state. The terminal 31 is connected to a power source (not shown), and a load (not shown) is connected to the terminal 32.
At this time, the electrical contact 30 of the electromagnetic contactor 3 is closed, and the current a of the main circuit flows through the electrical contact 30. Since the voltage generated between the movable contact 303 and the fixed contact 302 of the electrical contact 30 is approximately 0 [V], the gate voltage of the IGBT 40 is also 0 [V]. For this reason, IGBT40 will be in an OFF state.

FIG. 10 is a diagram at an initial stage when the electrical contact 30 changes from a closed state to an open state in the circuit of the second embodiment.
At this time, the electrical contact 30 of the electromagnetic contactor 3 is in an open state, and an arc as shown in FIG. Due to the generation of this arc, arc voltages are generated between the fixed contact 301 and the movable contact 303 and between the movable contact 303 and the fixed contact 302, respectively.

  The arc voltage is determined by the gap between the contact material of the electrical contact 30 and the electrode. If the gap between the electrodes is about 3 [mm], for example, the arc voltage has characteristics that depend substantially on the contact material. In this case, the arc voltage does not depend on the breaking current value, and a voltage of approximately 30 [V] is generated. Therefore, the arc voltages generated between the fixed contact 301 and the movable contact 303 and between the movable contact 303 and the fixed contact 302 are about 30 [V], respectively.

Here, when the resistance values of the resistors 41 and 42 of the voltage dividing circuit 45 are set to the same value, the gate voltage of the IGBT 40 becomes 15 [V] which is ½ of the arc voltage. At this time, the capacitor 44 is charged by the gate voltage of the IGBT 40, and the charging voltage becomes 15 [V]. For this reason, the IGBT 40 is switched from the off state to the on state.
FIG. 11 is a diagram when the current a flowing in the main circuit is commutated to the IGBT 40 side in the circuit of the second embodiment.

  When the IGBT 40 is switched to the ON state, as shown in FIG. 11, the current a of the main circuit flowing through the electromagnetic contactor 3 is switched to the circuit on the IGBT 40 side. By this commutation operation, the arc generated at the electrical contact 30 of the electromagnetic contactor 3 disappears. Then, the arc voltage applied to the gate of the IGBT 40 disappears. Accordingly, the electric charge charged in the capacitor 44 is discharged through the resistor 42.

FIG. 12 is a diagram at the time of completion of blocking in the circuit of the second embodiment.
As the charge of the capacitor 44 is discharged and the voltage applied to the gate of the IGBT 40 decreases, the IGBT 40 switches from the on state to the off state. Thereby, as shown in FIG. 12, the commutation operation of the current a of the main circuit is completed, and the current a of the main circuit is also completely cut off.
After completion of the interruption by the IGBT 40, an auxiliary contact (not shown) arranged on the power supply side with respect to the terminal 31 of the electromagnetic contactor 3 is opened to perform an electrical disconnection and a load connected to the terminal 32 (see FIG. (Not shown) and the power supply can be completely disconnected.

Here, the discharge rate (discharge time) of the charge of the capacitor 44 is determined by the time constant of the capacitor 44 and the discharge resistor 42. For this reason, by adjusting the time constant, it is possible to arbitrarily adjust or set the time from the extinction of the arc generated at the electrical contact 30 until the current a of the main circuit is cut off by turning off the IGBT 40.
Further, since the time constant controls the time (time interval) from turning on the IGBT 40 to turning it off, the current decay time in the arc-extinguishing device 4 is controlled by selecting the time constant on the order of ms, for example. it can. As a result, control such as suppression of the surge voltage immediately after interruption is also possible.

  Furthermore, in the second embodiment, an overvoltage suppression element 43 is provided to prevent an overvoltage from being applied to the gate of the IGBT 40. For this reason, voltage adjustment by the voltage dividing circuit 45 including the voltage dividing resistors 41 and 42 becomes unnecessary. That is, the voltage dividing resistor 41 becomes unnecessary. However, the voltage dividing resistor 41 also has a function as a charging resistor for the capacitor 44. Therefore, when the overvoltage suppression element 43 is provided, the resistance value of the voltage dividing resistor 41 can be set considering only the function as a charging resistor.

  As described above, in the second embodiment, when opening the electrical contact 30, the arc voltage generated on one contact side of the electrical contact 30 is applied to the gate of the IGBT 40, thereby turning on the IGBT 40 and turning on the main circuit. The current was commutated to the IGBT 40 side to extinguish the arc. In addition, after the arc disappears, the charge of the capacitor 44 is discharged, and the IGBT 40 is turned off.

  Therefore, according to the second embodiment, when the electrical contact 30 is opened, there is no need for a special control circuit that turns on the IGBT 40 in synchronization with the opening operation and then turns it off. The arc generated in the electrical contact can be eliminated by the configuration.

(Other embodiments)
(1) In the above embodiment, an IGBT (insulated gate bipolar transistor) is used as the semiconductor switching element of the arc extinguishing device 4, but a bipolar transistor, a MOS-FET, or the like may be used.
(2) In the above embodiment, the case where the present invention is applied to a circuit breaker for wiring or an electromagnetic contactor has been described. However, the present invention is applied to a switch in which two mechanical or contact switches are connected in series or an equivalent switch, and it is necessary to eliminate an arc generated when the switch is opened. can do.

  DESCRIPTION OF SYMBOLS 1 ... Circuit breaker for wiring, 3 ... Electromagnetic contactor, 4 ... Arc-extinguishing device, 11-14 ... Terminal, 21, 22, 30 ... Electrical contact, 31, 32 ... Terminal, 40 ... IGBT (semiconductor switch element), 41 , 42 ... resistor, 43 ... overvoltage suppressing element, 44 ... capacitor, 45 ... voltage dividing circuit, 301, 302 ... fixed contact, 303 ... movable contact

Claims (6)

An arc extinguishing device for erasing an arc generated in the mechanical switch when the switch is opened,
A semiconductor switch element is connected in parallel to the switch,
An arc extinguishing device, wherein an arc voltage generated by the switch is applied to a control terminal of the semiconductor switch element. The mechanical switch includes a series circuit that connects a first electrical contact and a second electrical contact in series,
The semiconductor switch element is connected in parallel to the series circuit,
The arc extinguishing device according to claim 1, wherein the control terminal of the semiconductor switch element is connected to a common connection portion of the first electrical contact and the second electrical contact. The mechanical switch includes a first fixed contact, a second fixed contact, and a movable contact that connects the first fixed contact and the second fixed contact.
The semiconductor switch element is connected in parallel to the switch,
The arc extinguishing apparatus according to claim 1, wherein a control terminal of the semiconductor switch element is connected to the movable contact.   The arc-extinguishing apparatus according to claim 2, further comprising a capacitor that holds a voltage of a control terminal of the semiconductor switch element.   The arc-extinguishing apparatus according to claim 4, further comprising a resistor that discharges the electric charge of the capacitor.   A switch comprising the arc extinguishing device according to any one of claims 1 to 5.

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