JP2012048839A - Semiconductor cutoff circuit - Google Patents

Abstract

Provided is a semiconductor cutoff circuit capable of suppressing an increase in circuit area and an increase in production cost without using a snubber circuit or a waveform generation circuit.
When a control unit 11 determines that a short circuit or overcurrent has occurred and a semiconductor circuit breaker 12 interrupts the current, the electrical connection state of switches S ₁ and S ₂ is switched. Thus, as the charge from the gate terminal of the semiconductor circuit breaker 12 to the capacitor C voltage adjustment is charged rapidly reduce the gate voltage V _G of the semiconductor circuit breaker 12. When the charging voltage adjusting capacitor C is completed, relatively through the resistor R ₂ having a large resistance value, the remaining charge stored from the gate terminal of the semiconductor circuit breaker 12 is allowed to flow slightly, the gate voltage V _G is gradually decreased.
[Selection] Figure 1

Description

  The present invention relates to a semiconductor cutoff circuit that protects a circuit when a short circuit occurs.

  In a power supply circuit including a DC power supply and a load fed from the DC power supply via a power supply line, a circuit breaker that cuts off a current is connected to the DC power supply and the load in order to protect the circuit when a short circuit occurs. It is provided between. Note that the short circuit includes, for example, a ground fault. As the circuit breaker, a fuse, a breaker using a semiconductor, a circuit breaker, or the like is used.

  When a short circuit occurs in a power supply circuit using a circuit breaker using a semiconductor, current interruption is started by a switching element composed of a collector and an emitter. At this time, an electromotive force according to the time change of the current flowing from the DC power supply and the inductance of the power feeding circuit is applied to the semiconductor.

  As a result, the voltage value between the collector and the emitter of the semiconductor suddenly increases, and the semiconductor may be damaged. Hereinafter, the circuit breaker using a semiconductor is referred to as “semiconductor circuit breaker”, and the voltage value between the collector and the emitter is referred to as “voltage value across the semiconductor circuit breaker”.

  In order to avoid damage to the semiconductor, a power supply circuit using a semiconductor circuit breaker generally includes a snubber circuit. For example, Non-Patent Document 1 discloses a technique for suppressing a rapid increase in the voltage value across the semiconductor circuit breaker by the snubber circuit.

  FIG. 9 is a diagram illustrating an example of a power feeding circuit using the semiconductor circuit breakers disclosed in Patent Document 1 and Non-Patent Document 1.

  The power supply circuit shown in FIG. 9 includes a DC power supply 80, a semiconductor cutoff circuit 100, and a load 90.

  The semiconductor cutoff circuit 100 includes a control unit 11, a semiconductor circuit breaker 12, a current detection unit 13, and a snubber circuit 101.

  In the snubber circuit 101, normally, as shown in FIG. 9, a resistor and a capacitor are connected in series, and the semiconductor circuit breaker 12 and the snubber circuit 101 are connected in parallel.

  In the power supply circuit shown in FIG. 9, the current detection unit 13 detects the current value of the current flowing through the positive electrode line 51. When the detected current value reaches a predetermined current value, the current detection unit 13 outputs a signal to the control unit 11. And the control part 11 will start interruption | blocking of the electric current which flows into the positive electrode line 51 by setting the semiconductor circuit breaker 12 into an OFF state, if the signal output from the electric current detection part 13 is received.

  When the semiconductor circuit breaker 12 starts to cut off the current, the current is commutated to the snubber circuit 101. Thereby, the rapid rise of the voltage value between the both ends of the semiconductor circuit breaker 12 is suppressed, and it can avoid that a semiconductor is damaged.

  In addition to the above-described method for avoiding damage to the semiconductor, a capacitor is inserted between the positive electrode line 51 and the negative electrode line 52 on the DC power supply 80 side, and after the semiconductor circuit breaker 12 is cut off, the DC power supply 80 side It is conceivable to cause the current to flow through the capacitor.

  There is also a method of gently limiting the current flowing through the semiconductor circuit breaker 12 by gradually decreasing the gate voltage in order to prevent an overvoltage from being generated in the semiconductor circuit breaker 12 when interrupting the current. In this method, the semiconductor circuit breaker 12 is normally turned on, but it is necessary to control the gate voltage of the semiconductor circuit breaker 12 using the waveform generator 11a so that the circuit breaker can be started quickly at the time of interruption. There is.

  The waveform generator 11a quickly lowers the gate voltage of the semiconductor circuit breaker 12 to a voltage level that changes the semiconductor circuit breaker 12 between the on state and the off state at the time of interruption, and quickly extracts the electric charge stored in the gate of the semiconductor circuit breaker 12. I am doing so. Thereafter, in a voltage region where the semiconductor circuit breaker 12 is changed between an on state and an off state, the waveform generation unit 11a slowly decreases the gate voltage of the semiconductor circuit breaker 12. Thereby, the electric charge is gradually extracted.

JP 2008-67440 A

http://www.fujielectric.co.jp/fdt/scd/technical/application/

  As described above, the use of the snubber circuit can avoid damage to the semiconductor circuit breaker. However, when a snubber circuit is used, the semiconductor cutoff circuit becomes larger by the amount of the snubber circuit. For example, when it is necessary to cut off the current flowing through both the positive and negative lines, a semiconductor breaker and a snubber circuit must be provided on both the positive line and the negative line, avoiding an increase in the size of the semiconductor breaker circuit. I can't. In this case, there is a problem that a space for installing the semiconductor cutoff circuit increases.

  In addition, when a snubber circuit is used, a current flows through the short-circuit system in order to charge the snubber circuit capacitor even after the interruption of the current flowing through the semiconductor circuit breaker is completed. Therefore, when the current output from the DC power supply is branched into a plurality of power supply systems by the current distribution device and supplied to the load, the voltage fluctuation generated by cutting off the current in the power supply system where the short circuit occurred There is a problem in that it propagates to a power supply system where no occurrence occurs.

  In addition, a method in which a capacitor is inserted between the positive electrode line and the negative electrode line on the DC power supply 80 side so that the current on the power supply side flows through this capacitor after the semiconductor breaker is shut down can be reduced by the size of the capacitor. The cut-off circuit becomes large. Since the voltage of the capacitor rises after the interruption, it is necessary to increase the capacitor capacity so as to satisfy a predetermined withstand voltage. Even when a high-breakdown-voltage element is used, there is a problem that voltage fluctuations in systems other than the short-circuit system greatly occur and the production cost increases.

  Furthermore, even when a waveform generation circuit for controlling the gate voltage of the semiconductor circuit breaker 12 is used, it is inevitable that the semiconductor circuit breaker becomes large and the production cost increases.

  Therefore, in view of the above-described problems, the present invention provides a semiconductor cutoff circuit capable of suppressing an increase in circuit area and production cost without using a snubber circuit or a waveform generation circuit. The purpose is to do.

In order to achieve the above object, a semiconductor cutoff circuit of the present invention is a semiconductor cutoff circuit provided between a load fed via a feed line from a DC power supply and the DC power supply,
A semiconductor breaker connected to the feeder line, and when the current value of the current flowing through the feeder line reaches a predetermined current value, the semiconductor circuit breaker starts cutting off the current flowing through the feeder line;
A gate voltage adjusting unit that is connected between the DC power source and a gate terminal of the semiconductor circuit breaker and controls a gate voltage of the semiconductor circuit breaker;
A switch switching control unit that switches an electrical connection state of the semiconductor circuit breaker from an on state to an off state when a current value of a current flowing through the feeder line exceeds a threshold current value;
The switch switching control unit
By switching the electrical connection state of the charging circuit so that the charge from the gate terminal of the semiconductor circuit breaker is charged by the charging circuit of the gate voltage adjusting unit when the semiconductor circuit breaker cuts off the current. Controls the gate voltage of the circuit breaker.

  Since the present invention is configured as described above, the gate voltage of the semiconductor circuit breaker can be controlled without using a waveform generation circuit or the like, and an overcurrent can be achieved without using a snubber circuit or a high breakdown voltage element. Measures can be taken. Since it is not necessary to use a snubber circuit, a waveform generation circuit, or the like for the semiconductor cutoff circuit, the semiconductor cutoff circuit can be manufactured in a small size and at low cost.

  Moreover, the space for installing the semiconductor cutoff circuit can be reduced as compared with the case where a snubber circuit or the like is used.

  In addition, it is possible to suppress voltage fluctuations propagating to a power feeding system in which a short circuit has not occurred when current is interrupted, compared to when a snubber circuit is used.

It is a figure which shows the structure of 1st Embodiment of the electric power feeding circuit to which the semiconductor cutoff circuit of this invention is applied. It is a flowchart which shows the flow of operation | movement of the control part 11 of the semiconductor cutoff circuit shown in FIG. It is a figure which shows the structure of the 1st modification of the electric power feeding circuit to which the semiconductor cutoff circuit of this invention is applied. It is a figure which shows the structure of the 2nd modification of the electric power feeding circuit to which the semiconductor cutoff circuit of this invention is applied. It is a figure which shows the structure of the 3rd modification of the electric power feeding circuit to which the semiconductor cutoff circuit of this invention is applied. It is a figure which shows the structure of the 4th modification of the electric power feeding circuit to which the semiconductor cutoff circuit of this invention is applied. It is a figure which shows the structure of the 5th modification of the electric power feeding circuit to which the semiconductor cutoff circuit of this invention is applied. It is a figure which shows the structure of the 6th modification of the electric power feeding circuit to which the semiconductor cutoff circuit of this invention is applied. It is a figure which shows an example of the conventional electric power feeding circuit using a semiconductor circuit breaker.

  Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. In each drawing referred to in the following description, components equivalent to those in the other drawings are denoted by the same reference numerals.

(Embodiment)
FIG. 1 is a diagram showing a configuration of an embodiment of a power feeding circuit to which a semiconductor cutoff circuit of the present invention is applied.

  As shown in FIG. 1, the power supply circuit according to the present embodiment includes a semiconductor cutoff circuit 10, a DC power supply 80, a load 90, and a DC power supply 91.

  In addition, the semiconductor cutoff circuit 10, the DC power supply 80, and the load 90 are connected by a power supply line including a positive electrode line 51 and a negative electrode line 52. Then, when a current flows from the DC power supply 80 through the power supply line, power is supplied to the load 90. The current detector 13 is connected to the first connection point on the power supply line and detects the current value of the current flowing through the first connection point. Then, the current detection unit 13 outputs the detected current value as a signal to the control unit 11.

  The semiconductor cutoff circuit 10 is provided between the DC power supply 80 and the load 90 and includes a control unit 11 and a semiconductor breaker 12.

Control unit 11 includes a switching control unit 11a, the gate voltage adjusting section 11b and a resistor _R 1 to R _3, the voltage adjustment capacitor C, a switch _S 1, _{S 2.}

The switch switching control unit 11a compares a predetermined current value with a flowing current value from the signal output from the current detection unit 13, and controls the switches S ₁ and S ₂ accordingly.

The resistor R ₁ is connected between a positive line 53 of a DC power supply 91 different from the DC power supply 80 used for driving the load 90 and the gate terminal of the semiconductor circuit breaker 12 via the control unit 11. The resistor R ₂ is connected between the negative electrode line 54 of the DC power source 91 and the gate terminal of the semiconductor circuit breaker 12 via the control unit 11. Resistor R ₃ is the capacitor C in series with a voltage regulator, is connected in parallel with the resistor R _2. The resistors R _{1 to} R ₃ are used for controlling the gate voltage V _G of the semiconductor circuit breaker 12.

Switch S ₁ is connected between positive electrode line 53 and the resistor R _1, the switching switch control signal phi ₁ that is output from the switching control unit 11a, the electrically connected state is changed. The switch S ₂ is connected between the negative line 54 and the resistor R _2, by switching the switching control signal phi ₂ is output from the switching control unit 11a, the electrically connected state is changed.

Voltage regulating capacitor C is on the resistor R ₃ in series, are connected in parallel to the resistor R _2. The voltage adjusting capacitor C is used to control the gate voltage V _G of the semiconductor circuit breaker 12 by charging the electric charge discharged from the gate terminal of the semiconductor circuit breaker 12.

The resistor R ₂ described above is selected to have a relatively large resistance value, and the resistor R ₃ is selected to have a relatively small resistance value. Further, when the charge that can be stored in the voltage adjusting capacitor C is removed from the charge stored in the gate of the semiconductor circuit breaker 12, the gate voltage V _G of the semiconductor circuit breaker 12 operates the semiconductor circuit breaker 12. The capacitance of the voltage adjusting capacitor C and the resistance values of the resistors R _{1 to} R ₃ are determined in advance so as to be slightly higher than the cutoff threshold voltage V _OFF .

  The semiconductor circuit breaker 12 is connected to a second connection point on the power supply line, and is switched between an on state and an off state by the control unit 11. When the semiconductor circuit breaker 12 is switched from the on state to the off state, the semiconductor circuit breaker 12 starts to interrupt the current flowing through the second connection point.

  Below, operation | movement of the semiconductor cutoff circuit 10 in the electric power feeding circuit comprised as mentioned above is demonstrated.

  First, a case where a short circuit has not occurred in the power feeding circuit shown in FIG. 1 will be described.

When no short circuit has occurred in the power supply circuit shown in FIG. 1, the switch switching control unit 11 a indicates that the amount of current flowing is smaller than the predetermined current amount from the signal output from the current detection unit 13. determination to, the electrical connection state of the switch S ₁ to oN state, issues a signal to turn oFF the electrical connection state of the switch S _2. As a result, a voltage is applied to the gate so that the semiconductor circuit breaker 12 can be energized, and the current flowing from the DC power supply 80 via the feeder line flows to the load 90.

  Next, a case where a short circuit occurs in the power feeding circuit illustrated in FIG. 1 will be described.

When a short circuit occurs in the power supply circuit shown in FIG. 1, the current flowing from the DC power supply 80 through the power supply line increases. Then, the switch switching control unit 11a determines from the signal output from the current detection unit 13 that the amount of current flowing is larger than the predetermined amount of current. Then, the control unit 11, an electrical connection state of the switch S ₁ is turned off, provides a signal to the electrical connection state of the switch S ₂ to the ON state. As a result, charges flow out from the gate terminal of the semiconductor circuit breaker 12. As described above, since the resistor R ₃ has a relatively small resistance value, a current flows mainly to the voltage adjusting capacitor C side until the voltage adjusting capacitor C is completely charged, and the gate terminal receives the current. can be extracted quickly charges that have been charged, the gate voltage V _G of the semiconductor circuit breaker 12 starts to decrease rapidly. Accordingly, the gate voltage V _G of the semiconductor circuit breaker 12, gradually decreases once in a short period of time until a voltage slightly higher than the cut-off threshold voltage V _OFF to operate the semiconductor circuit breaker 12.

Then, the gate voltage V _G of the semiconductor circuit breaker 12 reaches a voltage slightly higher than the cut-off threshold voltage V _OFF for operating the semiconductor circuit breaker 12, and the charging of the voltage adjusting capacitor C is completed. Then, the gate voltage V _G is stable, a sudden drop of voltage is suppressed. Since the resistor R ₂ has a relatively large resistance value, the remaining charge stored from the gate terminal of the semiconductor circuit breaker 12 and the charge stored in the voltage adjusting capacitor C are passed through the resistor R _2. Spill out little by little. As a result, the gate voltage V _G is gradually reduced, and finally the gate voltage V _G of the semiconductor circuit breaker 12 becomes 0V.

  In this way, it is possible to achieve both the start of cutting off the current in a short time and the gentle cut-off of the current without using a snubber circuit or a waveform generation circuit. For this reason, it is not necessary to use a capacitor or a semiconductor circuit breaker having a high breakdown voltage.

  Hereinafter, the flow of control for switching the electrical connection state of the semiconductor circuit breaker 12 by the control unit 11 will be described in detail with reference to FIGS. 2 and 3.

First, as shown in FIG. 2, switch control unit 11a outputs a switching switch control signal phi ₁ to switch the switch S ₁ to ON state, the switching switch control signal to switch the switch S ₂ to the OFF state and outputs the phi ₂ (step S101). Next, the control unit 11 inputs a current value from the current detection unit 13 (step S102), and determines whether a short circuit or an overcurrent has occurred in the circuit by determining whether the current value has exceeded a threshold current. To do. When the control unit 11 determines that the current value does not exceed the threshold current and no short circuit or overcurrent has occurred (NO in step S103), the control unit 11 returns to step S102 and repeats the process. The control unit 11, the current value exceeds the threshold current, if it is determined that a short circuit or overcurrent has occurred (YES in step S103), switching the electrical connection state of the switch S ₁ from the ON state to the OFF state, the switch switching on state electrical connection state S ₂ from the oFF state (step S104).

As described above, when the electrical connection state of the switches S ₁ and S ₂ is switched, the charge flows out from the gate terminal of the semiconductor circuit breaker 12 and the voltage adjusting capacitor C is charged. As described above, the gate voltage V _G of the semiconductor circuit breaker 12 is decreased at a stretch in a short time until reaching a voltage slightly higher than the cutoff threshold voltage V _OFF for operating the semiconductor circuit breaker 12.

When the gate voltage V _G of the semiconductor circuit breaker 12 reaches a voltage that is slightly higher than the cut-off threshold voltage V _OFF for operating the semiconductor circuit breaker 12, the charging of the voltage adjusting capacitor C is completed. As a result, the gate voltage V _G is stabilized, and a rapid decrease in the gate voltage V _G is suppressed. Through the resistor R _2, the remaining charge stored from the gate terminal and the voltage adjustment capacitor C of the semiconductor circuit breaker 12 flows out little by little. Thus, gradually reducing the gate voltage V _G, the gate voltage of the semiconductor circuit breaker 12 becomes 0V eventually. At this point, the control related to the interruption ends. Control unit 11, until the signal from the next external is input, the electrical connection state of the switch S ₁ and remains off, leaving the electrical connection state of the switch S ₂ to remain in the ON state.

As described above, when the short circuit occurs, it switches the switch S ₁ to the OFF state, switches the switch S ₂ to the ON state, charging the charge flowing from the gate terminal of the semiconductor circuit breaker 12 to the capacitor C voltage adjustment . Thus, drastically reduces the gate voltage V _G of the semiconductor circuit breaker 12. Then, by the charging voltage adjustment capacitor C completed, a sharp drop in the gate voltage V _G is suppressed, gradually reduce the gate voltage V _G of the semiconductor circuit breaker 12. Accordingly, the gate voltage V _G of the semiconductor circuit breaker 12 which has been performed using the waveform generation circuit or the like can be controlled without using the waveform generation circuit or the like.

(Modification)
FIG. 3 is a diagram illustrating a configuration of a semiconductor cutoff circuit 20 according to a modification of the semiconductor cutoff circuit 10.

Semiconductor cutoff circuit 10 in the embodiment described above, the voltage adjustment capacitor C and a resistor R ₃ connected in series, it was those connected in parallel with the resistor R _2. However, in the semiconductor cutoff circuit 20 shown in FIG. 3, connected in parallel with only the capacitor C voltage adjustment to the resistance R _2, and a resistor R _2, R ₃ connected in series. Even in a circuit having such a configuration, as described above, the gate voltage V _G of the semiconductor circuit breaker 12 can be rapidly increased until reaching a voltage slightly higher than the cutoff threshold voltage V _OFF for operating the semiconductor circuit breaker 12. It can be controlled to decrease and then gradually decrease.

  In the above-described embodiment, the case where the semiconductor circuit breaker 12 and the current detection unit 13 are connected to the positive line 51 has been described as an example. However, the semiconductor circuit breaker 12 and the current detection unit 13 include the negative line 52. It may be connected to the top. One of the semiconductor circuit breaker 12 and the current detection unit 13 may be connected to the positive electrode line 51 and the other may be connected to the negative electrode line 52. Furthermore, when detecting a short circuit or overcurrent, the short circuit or overcurrent can also be detected by a method other than using the current detection unit 13.

In the above-described embodiment, the semiconductor circuit breaker 12 is configured using an N-type MOSFET, but is not limited thereto. As in the semiconductor cutoff circuit 30 shown in FIG. 4, the semiconductor breaker 12 may be configured using a P-type MOSFET. In this case, as illustrated, the switch S ₁ is connected to the negative electrode line 54 of the DC power supply 91, and the switch S ₂ is connected to the positive electrode line 53 of the DC power supply 91.

  In the above-described embodiment, the DC power supply 91 is provided separately from the DC power supply 80 used for driving the load 90. However, as shown in FIG. 5, in order to control the gate voltage of the semiconductor circuit breaker 12 by converting the voltage fed from the feed line using the isolated DC / DC converter 92 instead of using the DC power supply 91. May be generated.

  In addition, as shown in FIG. 6, the semiconductor circuit breaker 12 is provided on the positive electrode line 51, the semiconductor circuit breaker 12 is configured by a P-type MOSFET, and a negative voltage is applied to the gate terminal of the semiconductor circuit breaker 12. In order to control the gate voltage of the semiconductor breaker 12, the non-insulated DC / DC converter 93 is used to convert the voltage fed from the feeder line. A voltage may be generated. In addition, the semiconductor circuit breaker 12 is provided on the negative electrode line 52, the semiconductor circuit breaker 12 is comprised by N-type MOSFET etc., and + voltage is applied to the gate terminal of the semiconductor circuit breaker 12, and energization / breaking operation is performed. In the case where it is, a non-insulated DC / DC converter 93 may be provided to convert the voltage supplied from the power supply line to generate a voltage for controlling the gate voltage of the semiconductor circuit breaker 12.

Further, instead of using the non-insulated DC / DC converter 92 described above, the gate voltage of the semiconductor circuit breaker 12 may be controlled by the circuit configuration of the semiconductor circuit 40 shown in FIG. As shown in FIG. 7, the gate voltage adjustment unit 11c, switches _{S 1} and resistor _{R 1} is connected to the negative line 52 side, the switch _{S 2,} resistors _R 2, _{R 3} and the voltage adjustment capacitor C is negative line 51 is connected. Further, the resistance R ₄ is connected to the positive line 51 side.

When the semiconductor circuit breaker 12 is interrupted, each switch is operated as described above to divide the voltage from the DC power source 80 by the resistor R ₁ and the resistor R ₄ to control the gate voltage of the semiconductor circuit breaker 12. can do. In addition, when the discharge of the voltage adjusting capacitor C proceeds too quickly, a switch that operates with the switching switching control signal φ ₁ is provided on the DC power supply 80 side of the resistor R ₄ to control the gate voltage of the semiconductor circuit breaker 12. You can also.

  In the case where the voltage of the DC power supply 80 described above is compatible with the gate voltage of the semiconductor circuit breaker 12, the above-described insulation type DC / DC converter 92 and non-insulation type DC / DC converter 93 are not provided. The line 51 and the negative electrode line 52 and the gate voltage adjusting unit 11b may be directly connected, and the voltage of the DC power supply 80 may be used as it is for controlling the gate terminal.

  In the above-described embodiment, for example, in order to suppress an increase in current from when the current detection unit 13 detects a predetermined current value until the semiconductor circuit breaker 12 starts interrupting the current, FIG. As shown in FIG. 8, inductors 94 and 95 may be connected on the feeder line.

(Summary)
The current can be cut off without damaging the semiconductor circuit breaker 12 without using a snubber circuit, a waveform generation circuit, or the like. When the control unit 11 determines that a short circuit or overcurrent has occurred, the electrical connection state of the switches S ₁ and S ₂ is switched, and a charge is charged from the gate terminal of the semiconductor circuit breaker 12 to the voltage adjusting capacitor C to make the semiconductor. once reduced in a short time to reach a voltage slightly higher than the cut-off threshold voltage V _OFF to the gate voltage V _G of the circuit breaker 12 is operated semiconductor breaker 12. Then, slowly decreasing the gate voltage _{V G} through the resistor _{R 2.}

  INDUSTRIAL APPLICABILITY The present invention can be used as a semiconductor cutoff circuit for protecting various loads operating with a DC power supply from short circuits and overcurrent.

DESCRIPTION OF SYMBOLS 10,20 Semiconductor cutoff circuit 11 Control part 11a Switch switching control part 11b Gate voltage adjustment part 12 Semiconductor circuit breaker 13 Current detection part 51 Positive electrode line 52 Negative electrode line 80 DC power supply 90 Load

Claims (10)

A semiconductor cutoff circuit provided between a load fed via a feeder line from a DC power source and the DC power source,
A semiconductor breaker connected to the feeder line, and when the current value of the current flowing through the feeder line reaches a predetermined current value, the semiconductor circuit breaker starts cutting off the current flowing through the feeder line;
A gate voltage adjusting unit that is connected between the DC power source and a gate terminal of the semiconductor circuit breaker and controls a gate voltage of the semiconductor circuit breaker;
A switch switching control unit that switches an electrical connection state of the semiconductor circuit breaker from an on state to an off state when a current value of a current flowing through the feeder line exceeds a threshold current value;
The switch switching control unit
By switching the electrical connection state of the charging circuit so that the charge from the gate terminal of the semiconductor circuit breaker is charged by the charging circuit of the gate voltage adjusting unit when the semiconductor circuit breaker cuts off the current. A semiconductor circuit that controls the gate voltage of the circuit breaker. The semiconductor cutoff circuit according to claim 1,
The gate voltage adjustment unit is
A first resistor connected between one of the feeder wires and a gate terminal of the semiconductor circuit breaker;
A second resistor connected between the other polar line of the feeder line and the gate terminal of the semiconductor breaker;
A third resistor connected in parallel to the second resistor;
A first switching element connected between the one polar line and the first resistor;
A second switching element connected between the other polar line and the second resistor;
A semiconductor cutoff circuit including a voltage adjusting capacitor connected in parallel to the second resistor and connected in series with the third resistor. The semiconductor cutoff circuit according to claim 1,
The gate voltage adjustment unit is
A first resistor connected between the one pole wire and a gate terminal of the semiconductor circuit breaker;
A second resistor connected between the other polar line and the gate terminal of the semiconductor breaker;
A third resistor connected in series with the second resistor;
A first switching element connected between the one polar line and the first resistor;
A second switching element connected between the other polar line and the second resistor;
A semiconductor cutoff circuit comprising: a voltage adjusting capacitor connected in parallel to the second resistor. The semiconductor cutoff circuit according to claim 2 or 3,
The switch switching control unit
Before starting the shutoff, switch the electrical connection state of the first switching element to the on state, switch the electrical connection state of the second switching element to the off state,
When the shutoff is started, the electrical connection state of the first switching element is switched to an off state, and the electrical connection state of the second switching element is switched to an on state, whereby the electrical connection of the semiconductor circuit breaker is performed. A semiconductor cutoff circuit that switches the state from on to off. In the semiconductor cutoff circuit according to any one of claims 2 to 4,
A semiconductor cutoff circuit having a fourth resistor connected between the other polar line of the feeder line and a gate terminal of the semiconductor breaker. The semiconductor cutoff circuit according to claim 5,
A semiconductor cutoff circuit having a third switching element connected between the other polar line of the feeder line and the fourth resistor. The semiconductor cutoff circuit according to claim 6,
The switch switching control unit
By switching the electrical connection state of the third switching element to be the same as the electrical connection state of the first switching element, the electrical connection state of the semiconductor breaker is changed from the on state to the off state. Switching semiconductor cutoff circuit. In the semiconductor cutoff circuit according to any one of claims 1 to 4,
The DC power supply is
A driving DC power source for driving the load, and a control DC power source for controlling the semiconductor circuit breaker,
The gate voltage adjustment unit is
A semiconductor breaker circuit connected between the control DC power source and a gate terminal of the semiconductor breaker to control a gate voltage of the semiconductor breaker. In the semiconductor cutoff circuit according to any one of claims 1 to 4,
The gate voltage adjustment unit is
A semiconductor cutoff circuit that is connected to the feeder line via a DC / DC converter and controls a gate voltage of the semiconductor breaker. In the semiconductor interruption circuit according to any one of claims 1 to 7,
The gate voltage adjustment unit is
A semiconductor cutoff circuit that is connected to the feeder line to which an inductor is connected and controls a gate voltage of the semiconductor breaker.

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