JP2014241187A - DC switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a DC switch which has a small-sized and compact configuration and improves an opening/closing performance by utilizing versatile control equipment such as an electromagnetic contact or a breaker as a mechanical switch and combining a semiconductor switch such as IGBT therewith so as to suppress arc generation.SOLUTION: A DC switch comprises: a semiconductor switch 4; a mechanical parallel contact 9; and a serial disconnection contact 10. When closing a main circuit, the disconnection contact 10, the semiconductor switch 4 and the parallel contact 9 are turned on in this order. When opening the main circuit, the parallel contact 9, the semiconductor switch 4 and the disconnection contact 10 ate turned off in this order. The parallel contact 9 and the disconnection contact 10 are allocated to different poles of an electromagnetic contact 13, the contacts are collectively interconnected to an opening/closing operation mechanism 11 of the electromagnetic contact 13, and a wipe amount of the disconnection contact 10 is then set larger than a wipe amount of the parallel contact 9. When turning on or turning off the switch, the parallel contact 9 and the disconnection contact 10 are caused to perform electrode opening and closing operations in a predetermined order while deviating the timing.

Description

  The present invention relates to a DC switch applied to a DC power supply circuit such as a photovoltaic power generation system or a storage battery system.

In recent years, with the widespread use of DC power supply systems such as solar power generation, the demand for DC switches as distribution control devices applied to DC power supply circuits has increased.
By the way, in the conventional DC switch, countermeasures for extinguishing arcs generated between the main circuit contacts (mechanical contacts) in accordance with the opening / closing operation are a major issue. That is, direct current, unlike alternating current, does not pass a zero point of current, and it is difficult to extinguish an arc generated between fixed / movable contacts in accordance with an opening / closing operation.

  In this regard, a semiconductor switch is connected in parallel between the contact points of the mechanical switch, and the circuit current is commutated to the semiconductor switch when the mechanical switch is opened to extinguish the arc generated between the contact points of the mechanical switch. An arc erasing device for a switch is known in which the semiconductor switch is controlled to be OFF to cut off the circuit current (see, for example, Patent Document 1).

  Further, as the arc extinguishing type DC switch, a mechanical series switch is added to the switch circuit in which a mechanical switch and a semiconductor switch are connected in parallel to disconnect the switch circuit, and the semiconductor switch is controlled to be OFF. A DC switch has been proposed in which, after the current is cut off, the series switch for disconnection is opened to completely disconnect the DC circuit (see, for example, Patent Document 2).

  Next, the configuration and operation of the DC switch disclosed in Patent Document 2 are shown in FIGS. In FIG. 6, 1 is a DC power source, 2 is a load, 3 is a DC switch connected to a power supply circuit between the DC power source 1 and the load 2, and the DC switch 3 is a semiconductor switch (IGBT, MOS-FET). 4), a mechanical parallel switch 5 connected in parallel to the semiconductor switch 4, and a mechanical series switch 6 for disconnection connected in series. Reference numeral 7 denotes a switch control circuit (digital logic circuit) that controls turning on and off of each switch, and reference numeral 8 denotes a control switch that gives an open / close command to the DC switch 3 from the outside. Note that two electromagnetic relays are used as the parallel switch 5 and the series switch 6 incorporated in the illustrated DC switch 3.

  FIG. 7 is a time chart showing the opening / closing operation of the DC switch 3. At the time of turning on / off, the semiconductor switch 4, the parallel switch 5, and the series switch 6 are turned on / off in the following operation sequence. (OFF).

  That is, when an input command is given to the control switch 8 from the outside, the series switch 6 is first switched on (closed) at time t1 based on the input command, and then the semiconductor switch 4 is delayed by a predetermined time τ1 from t1. The ON operation (t2) is performed, and finally the parallel switch 5 is turned on (t3) with a delay of time τ2 from t2. As a result, the DC power supply circuit is closed, and energization to the load 2 is established.

  On the other hand, when the control switch 8 is turned OFF by an external opening command when the DC power supply circuit is opened, the parallel switch 5 is first disconnected (opened) at time t4, and then the semiconductor switch 4 is delayed by time τ3 from t4. An OFF operation (t5) is performed, and finally the series switch 6 is disconnected with a delay of time τ4 from t5, so that the DC circuit is completely disconnected.

  As described above, when the DC circuit is opened and closed, the semiconductor switch 4, the parallel switch 5, and the series switch 6 are turned on and off in a predetermined order so that an arc is generated between the contacts. It is possible to close and open the mechanical parallel switch 5 and the DC switch 6 by suppressing them.

  That is, when the DC circuit is closed, the series switch 6 is first turned on. However, when the series switch 6 is turned on (t1), the semiconductor switch 4 is turned off and no current flows through the main circuit. Even if the mechanical contact bounces during the closing process of No. 6, it can be introduced without any arcing problem. Further, when the parallel switch 5 is turned on after the semiconductor switch 4 is turned on, the circuit current is energized to the semiconductor switch 4, so that no arc is generated due to contact bounce at the time of closing.

  Even when the DC circuit is opened, when the parallel switch 5 is opened for the first time, the circuit current is transferred to the semiconductor switch 4 so that the circuit can be opened without generating an arc. Furthermore, the series switch 6 that is disconnected at the end of the circuit opening operation is opened in a non-voltage state after the semiconductor switch 4 is turned off and the circuit current is cut off, so that the opening can be performed without generating an arc.

  In the DC switch 3 disclosed in Patent Document 1, the semiconductor switch 4 is maintained in an ON state even during energization of the DC circuit. In this steady energization state, most of the circuit current is a mechanical parallel switch 5. Therefore, there is little loss in the semiconductor switch 4 (for example, IGBT), and there is almost no problem in practical use.

Japanese Patent Laid-Open No. 8-106839 JP 2012-28193 A

  By the way, the DC switch (Patent Document 2) described above has the following problems in commercialization. That is, since the DC switch 3 is equipped with two independent electromagnetic relays as the mechanical parallel switch 5 and the series switch 6, the switch is increased in size.

  Further, as a control means for controlling the on / off of each of the parallel switches 5 and the series switches 6 in a predetermined order in response to an open / close command from the outside, a switch control circuit (digital logic circuit) is used in the DC switch 3 of FIG. 7, but the addition of such an electronic control circuit 7 increases the cost of the DC switch product.

  The present invention has been made in view of the above points, and an object of the present invention is to use a general-purpose control device such as an electromagnetic contactor and a breaker as a mechanical switch, and combine this with a semiconductor switch such as an IGBT. The present invention is to provide a small-sized, compact and excellent DC switch having the same function as the DC switch disclosed in the above.

To achieve the above object, according to the present invention, a DC switch is connected to a power supply circuit between a DC power source and a load to open and close the circuit, the DC switch includes a semiconductor switch, A mechanical parallel contact connected in parallel to the semiconductor switch, and a mechanical disconnect contact connected in series to the semiconductor switch. When the circuit is closed, the semiconductor switch, the parallel contact, and the disconnect contact are connected to the disconnect contact, the semiconductor switch, and the parallel contact. In order to cut in order of parallel contacts, semiconductor switch, disconnect contact at the time of opening,
Assign each contact of the parallel contact and disconnecting contact to different poles of the multipolar switch, and link the contacts to the switching operation mechanism of the multipolar switch at the same time. The contact wipe amount is set to be larger than the contact wipe amount, and the opening and closing operation timing is shifted relative to the parallel contact (Claim 1). It can be configured in the following manner.
(1) A height difference is provided between a base on which the fixed contact of the disconnecting contact is mounted and a base on which the fixed contact of the parallel contact is mounted (Claim 2).
In (2), the free length of the contact spring interposed between the movable contact of the disconnecting contact and the opening / closing operation mechanism is determined to be longer than the contact spring of the parallel contact.

  In addition, a multipolar electromagnetic contactor having two or more poles or a breaker is used as a multipolar switch equipped with the parallel contact and disconnecting contact (claim 4).

  In the DC switch having the above configuration, when a switch (for example, a two-pole electromagnetic contactor) is turned on / off based on a DC circuit closing / opening command, a mechanical parallel contact linked to the switching operation mechanism The disconnecting contact is closed and opened in order at a timing corresponding to a preset wipe amount difference. That is, when the switch is disconnected, the parallel contact is opened first, and the disconnect contact is opened later. On the other hand, contrary to the above, the disconnect contact is closed first, and the parallel contact is closed after this. On the other hand, the semiconductor switch is an intermediate circuit in which the parallel contact and the disconnect contact are opened and closed at different timings according to the operating characteristics of the switch that opens and closes according to the wipe amount difference of the mechanical contact described above. ON / OFF control at timing.

  As a result, the two mechanical switches (parallel switch, series switch) incorporated in the DC switch disclosed in Patent Document 2 are replaced with one multipolar switch (for example, an electromagnetic contactor). The DC switch can be made smaller and more compact. In addition, by setting the contact wipe amount difference between the parallel contact and the disconnect contact that are allotted to different poles by linking with the switching mechanism of the multipolar switch, the electronic control circuit (digital logic circuit) ), It is possible to open and close the parallel contacts and disconnect contacts in a predetermined order by shifting the timing when the switch is opened and closed, thereby reducing the product cost.

  Note that general-purpose control devices such as electromagnetic contactors are operated by an open / close operation mechanism that opens and closes the contacts of each pole in response to an external command, and the time between contacts based on the contact wipe amount difference. While the typical timing difference is on the order of msec, the switching time for turning on and turning off the semiconductor switch is on the order of μsec, so the mechanical parallel contact and disconnect contact are in the middle of opening and closing at different timings. It is possible to control the ON (turn on) and OFF (turn off) by giving a trigger signal to the semiconductor switch at the timing.

It is a block diagram of the DC switch by the Example of this invention comprised by mounting a semiconductor switch in a 2 pole type magnetic contactor, (a) is a circuit diagram of a switch, (b) is the structure of an electromagnetic contactor FIG. Opening of each contact where a step difference is provided between the pedestal bases of the DC switch mounted on the electromagnetic contactor shown in FIG. FIG. 4 is an explanatory diagram schematically showing a closing operation, and (a), (b), and (c) are diagrams showing an opening state of each contact, a state during an opening / closing operation, and a closing state, respectively. . For the parallel contact and disconnect contact of the DC switch mounted on the electromagnetic contactor shown in Fig. 1, the contact spring length is changed to set the wipe amount difference between the parallel contact and disconnect contact. It is operation | movement explanatory drawing typically represented, Comprising: (a), (b), (c) is a figure showing the opening state of each contact, an intermediate operation state, and a closing state, respectively. It is a figure showing the path | route of the circuit current at the time of cutting | disconnection of a switch about the direct current switch of this invention Example, (a) is the closed circuit state of a switch, (b) is the state immediately after parallel contact opening, ( c) is a diagram corresponding to a state in which the circuit current is commutated to the semiconductor switch, and (d) is a diagram corresponding to a disconnection state in which the disconnect contact is open. FIG. 5 is a diagram illustrating a circuit current path when the switch is turned on in the DC switch of the embodiment of the present invention, where (a) is a disconnecting state of the switch, (b) is a state immediately after the disconnecting contact is turned on, (c ) Is a diagram corresponding to a state in which a semiconductor switch is turned on, and (d) is a diagram corresponding to a switch-on state in which a parallel contact is closed. FIG. 6 is a switch circuit diagram of a conventional DC switch disclosed in Patent Document 1. FIG. 7 is a time chart showing the operation sequence of parallel switches, series switches, and semiconductor switches when the DC switch of FIG. 6 is turned on and off.

Hereinafter, embodiments of the present invention will be described based on the examples shown in FIGS.
In this embodiment, two or more poles, for example, a two-pole electromagnetic contactor 13 is applied as a mechanical switch of a DC switch, and a semiconductor switch (IGBT) 4 is mounted on the electromagnetic contactor 13, as shown in FIG. After allocating the parallel contacts 9 and disconnect contacts 10 corresponding to the mechanical parallel switches 5 and 6 to the different poles of the magnetic contactor 13, respectively, the parallel contacts 9 and disconnect contacts 10 are connected as described below. Different contact wipe amounts are set between them to shift the timing of the closing and opening operations for each contact, and the detailed structure will be described below.

  That is, in the switch circuit diagram of FIG. 1A, the parallel contact 9 and the disconnecting contact 10 in the figure correspond to the mechanical parallel switch 5 and the series switch 6 in the DC switch of FIG. The contact 9 and the disconnecting contact 10 are assigned to the respective poles of the two-pole electromagnetic contactor 13 shown in FIG. 1B, and the respective contacts are opened and closed by an open / close command from the outside. In the figure, reference numeral 11 denotes an opening / closing operation mechanism for driving each pole contact of the electromagnetic contactor 13 to open and close at once, 12 a coil drive unit of the electromagnetic contactor 13, and 14 an electromagnetic contactor. 13 housings, 15 is an operating electromagnet comprising a fixed iron core 15a, a movable iron core 15b, an operating coil 15c, and a return spring 15d, 16 is a pair of left and right fixed contacts mounted on the terminal base 14a of the housing 14, and 17 is each pole A terminal screw 18 provided on the fixed contact 16, 18 is a bridge-shaped movable contact (a contact) facing the fixed contact 16, 19 is a movable contact support that holds the movable contact 18 and is connected to the movable iron core 15 b, 20 Is a contact spring (a compression coil spring that secures a required contact contact pressure by pressing the movable contact 18 against the fixed contact 16 in the closed position), and the fixed contact 16 has its stator (contact piece) as a housing. 14 terminal bases It is placed supported on 4a. The operation of the electromagnetic contactor 13 is well known, and the description thereof is omitted here.

  A semiconductor switch (IGBT) 4 mounted on the electromagnetic contactor 13 is connected in parallel to the parallel contact 9. The electromagnetic contactor 13 is connected to the terminals 17 of the parallel contact 9 and the disconnect contact 10 in series as shown in FIG. Connected.

  Here, regarding the contact mechanism of the parallel contact 9 and the disconnecting contact 10 assigned to the different poles of the electromagnetic contactor 13, the contact wipe amount (the movement of the contact support 19 from the start of contact until the contact is completely closed) The wipe amount of the disconnecting contact 10 is set to be larger than the wipe amount of the parallel contact 9 by the wipe amount setting means shown in FIG.

  That is, in the contact mechanism of FIG. 2, a step Δh is provided on the terminal base 14a on which the stators of the fixed contacts 16 corresponding to the contacts of the parallel contacts 9 and the disconnect contacts 10 are placed side by side. ) Is set so that the gap g2 between the fixed contact / movable contact of the disconnecting contact 10 is smaller than the gap g1 between the fixed contact / movable contact of the parallel contact 9 (g2 <g1).

  As a result, the wipe amount of the disconnect contact 10 is set larger than the wipe amount of the parallel contact 9, and the disconnect contact is preceded by the parallel contact 9 when the switch is turned on, as shown in FIGS. In the case of disconnection, the parallel contact 9 opens before the disconnecting contact 10 at the time of disconnection, and the timing of the opening and closing operations is shifted between the two contacts.

  On the other hand, in the contact mechanism shown in FIGS. 3A to 3C, the contact springs 20a and 20b interposed between the movable contact 18 and the movable contact support 19 of the parallel contact 9 and the disconnect contact 10 are connected to the disconnect contact side. The free length L2 of the contact spring 20b inserted in the contact spring 20b is set longer than the free length L1 of the contact spring 20a inserted in the parallel contact side (L2> L1). Thus, like the contact mechanism of FIG. 2, the wipe amount of the disconnect contact 10 is larger than the wipe amount of the parallel contact 9, and as shown in FIGS. The disconnecting contact 10 is closed first, and at the time of disconnection, the parallel contact 9 is opened before the disconnecting contact 10 so that the timing of the opening and closing operations is shifted.

  For the semiconductor switch (IGBT) 4 mounted on the electromagnetic contactor 13 and connected in parallel to the parallel contact 9, the parallel contact 9 and the disconnect contact 10 are opened at different timings based on an open / close command from the outside. , The timing is adjusted during the closing operation, and a trigger signal is applied to the gate of the IGBT to perform ON / OFF control.

  By assigning the parallel contact 9 and the disconnect contact 10 to the multipolar electromagnetic contactor 13 as described above, two independent parallel switches 5 are provided as in the conventional DC switch shown in FIG. The series switch 6 can be combined into one electromagnetic contactor 13 to reduce the size and size of the DC switch. Further, the parallel contact 9 and the disconnecting contact 10 are linked to the switching operation mechanism 11 (see FIG. 1A) of the electromagnetic contactor 13, and then the parallel contact 9 and the disconnecting contact 10 are disconnected as described in FIG. By setting the wipe amount difference with the contact 10 to shift the timing of the opening and closing operations, the electronic control circuit provided in the DC switch of FIG. 6 can be omitted, and the product cost can be reduced. Reduction can be achieved.

  Next, with regard to the DC switch of the illustrated embodiment, the circuit current energization path when the switch is disconnected and turned on is divided into FIGS. 4A to 4D and FIGS. 5A to 5D and displayed. To do. 4A is a steady energized state in which a DC switch is turned on, and FIG. 4B is a circuit diagram in which the semiconductor switch 4 is ON-controlled during the opening operation of the parallel contact 9 and the circuit current is controlled by the semiconductor switch 4. (C) shows the state after opening of the parallel contact 9, and (d) shows the disconnection in which the disconnecting contact 10 is opened with no voltage after the semiconductor switch 4 is controlled to be OFF. It represents the state.

  5A shows a state in which the DC switch is cut and no circuit current flows, FIG. 5B shows a state in which the disconnecting contact 10 is turned on with no voltage, and FIG. 5C shows the semiconductor switch 4. (D) shows a steady energized state in which the semiconductor switch 4 is turned off after the parallel contact 9 is turned on.

  4 and 5, the semiconductor switch 4 is ON-controlled only for a short time according to the timing at which the mechanical contacts (parallel contact 9, disconnecting contact 10) are opened and closed by a DC switch opening / closing command. However, in the steady energization state, the switch is turned off to keep the steady loss of the semiconductor switch 4 low. However, as in the time chart shown in FIG. 7, the semiconductor switch 4 is kept in the on state even during steady energization of the DC switch. It may be held to simplify the ON / OFF control of the semiconductor switch 4. Moreover, you may make it apply the structure of this invention to a breaker (circuit breaker for wiring) whose number of poles is 2 or more as a DC switch.

DESCRIPTION OF SYMBOLS 1 DC power supply 2 Load 3 DC switch 4 Semiconductor switch 9 Parallel contact 10 Disconnecting contact 11 Opening / closing operation mechanism 13 Electromagnetic contactor (multipolar switch)
14a Terminal base 15 Operating electromagnet 16 Fixed contact 18 Movable contact 19 Movable contact support 20 Contact spring

Claims (4)

A DC switch connected to a power supply circuit between a DC power source and a load to open and close the circuit, the DC switch comprising a semiconductor switch and a mechanical parallel contact connected in parallel to the semiconductor switch; and It is equipped with a mechanical disconnection contact connected in series to a semiconductor switch. When closed, the semiconductor switch, parallel contact, and disconnection contact are inserted in this order: disconnection contact, semiconductor switch, parallel contact, and when open, parallel contact, semiconductor switch, disconnection contact In what was cut in the order of
Assign each contact of the parallel contact and disconnecting contact to different poles of the multipolar switch, and link the contacts to the switching operation mechanism of the multipolar switch at the same time. A DC switch characterized in that it is set larger than the wipe amount of the contact and the timing of the opening and closing operation is shifted relative to the parallel contact.   2. The DC switch according to claim 1, wherein each of the contact of the parallel contact and the disconnecting contact has a fixed contact mounted on a terminal base of the switch casing, and a plurality of movable contacts facing the fixed contact are provided via a contact spring. It is structured to be linked to the opening / closing operation mechanism of the polar switch, and is characterized in that a height step is provided between the base on which the fixed contact of the disconnecting contact is mounted and the base on which the fixed contact of the parallel contact is mounted. DC switch.   2. The DC switch according to claim 1, wherein each of the contact of the parallel contact and the disconnecting contact has a fixed contact mounted on a terminal base of the switch casing, and a movable contact facing the fixed contact is a contact spring comprising a coil spring. It is structured to be linked to the opening / closing operation mechanism of the multipolar switch through the contact spring, and the free length of the contact spring interposed between the movable contact of the disconnecting contact and the opening / closing operation mechanism is set to be larger than the contact spring of the parallel contact. DC switch characterized by a long set.   The DC switch according to any one of claims 1 to 3, wherein a multipolar electromagnetic contactor having two or more poles or a breaker is used as a multipolar switch having parallel contacts and disconnecting contacts. DC switch to do.