JP2020014045A - Bidirectional switch circuit - Google Patents

Abstract

To provide a bidirectional switch circuit which prevents overvoltage breakdown of the MOSFET, and the like, at the translocation source, by preventing the current of a self-extinguishing type semiconductor element, such as an IGBT, at the communication destination of the current flowing through a thyristor from saturating.SOLUTION: In a bidirectional switch circuit for insertion into a cable way through which a bidirectional current flows, a first single direction switch part Sformed by connecting a thyristor Thand a MOSFET Qin series in forward direction, and a second single direction switch part Sformed by connecting a thyristor Thand a MOSFET Qin series in forward direction are connected in reverse parallel, the reverse parallel circuit is connected in series with cable ways 100, 100', both ends of the reverse parallel circuit are connected, respectively, with the AC input terminals of a diode bridge DB, and an IGBT Qconstituting a third single direction switch part Sis connected between the DC output terminals of the diode bridge DB in the forward direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a bidirectional switch circuit capable of passing and blocking a bidirectional current, and more particularly, to a self-extinguishing type semiconductor device such as an IGBT (insulated gate bipolar transistor) or a MOSFET (metal oxide semiconductor field effect transistor). And a thyristor.

2. Description of the Related Art Conventionally, various switch circuits and power converters have been provided for the purpose of reducing conduction loss and switching loss of semiconductor switching elements.
For example, FIG. 6 shows an AC power adjusting device described in Patent Literature 1, in which AC is an AC power supply, Q _1a , Q _1b , Q _1c , and Q _1d are IGBTs, and Q _2a , Q _2b , Q _2c , and Q _2d. Is a MOSFET connected in parallel to each IGBT, L is a reactor, C is a capacitor, and R is a load. _{Here, IGBT Q} 1a, Q _1b and MOSFET Q _2a, bidirectional switch SW ₁ is constituted by _{Q 2b,} the bidirectional switch SW ₂ is composed of _{IGBT Q 1c,} Q _1d and MOSFET _{Q 2c,} Q _2d .

In this conventional technique, the bidirectional switches SW ₁ and SW ₂ are turned on / off by a control circuit (not shown), and an AC voltage having an amplitude different from that of the AC power supply AC is generated and supplied to the load R. At this time, when the voltage between both ends of the bidirectional switches SW ₁ and SW ₂ is equal to or lower than a predetermined value or when the load is light, the MOSFET is turned on and off, and when the voltage between both ends of the bidirectional switches SW ₁ and SW ₂ exceeds the predetermined value. Under heavy load, the IGBT is turned on and off to reduce conduction loss and switching loss of each element.

Next, FIG. 7 shows a rectifier circuit described in Patent Document 2.
In FIG. 7, _{SW 11} is MOSFET Q _2a, a bidirectional switch composed of _{Q 2b, SW 12} is bi-directional switch comprising a _{MOSFET Q 2c, Q 2d, D} 1 ~D 6 a _{diode, L 1,} L ₂ in the reactor The other parts are denoted by the same reference numerals as in FIG.
In this conventional technique, diodes D ₁ , D ₂ , D ₃ , and D _{4 use} low-speed elements having a large surge current resistance, and diodes D ₅ and D ₆ use a high-speed element having a small surge current resistance. , While the MOSFETs Q _2b and Q _2d are always turned on, the MOSFETs Q _2a and Q _2c are switched at high speed.

When the voltage of the AC power supply AC becomes higher than the voltage of the capacitor C when the power is turned on or when the power is restored after a power failure, the MOSFETs Q _2b and Q _2d are turned off, and the inrush current flowing through the capacitor C is reduced by the low-speed diode D _1. , D ₄ or D ₂ , D ₃ . This prevents the inrush current from flowing through the MOSFETs Q _2a and Q _2c and the diodes D ₅ and D ₆ to protect them. Further, _MOSFET Q _2b, because the maximum voltage applied to the _{Q 2d} are each diode _D 2, a low voltage equal to the forward voltage drop of the _{D 4, MOSFET} Q 2b, the _{Q 2d} low withstand voltage and a small element of conduction losses Can be used.

FIG. 8 shows a power factor correction circuit (PFC circuit) described in Patent Document 3. 8, C ₁ is a filter capacitor, DB is a diode bridge, Q ₃₁ and Q ₃₂ are MOSFETs, D ₇ is a fast recovery diode, D ₈ is a rectifier diode, and the other parts are the same as those in FIGS. 6 and 7. Are attached.

In this prior art, while maintaining the sine wave almost in phase with the AC input voltage AC input current by turning on and off the MOSFET Q _31, and supplies a desired DC voltage to the load R. Also, a series circuit of a rectifier diode D ₈ having a small conduction loss and a MOSFET Q ₃₂ having a low withstand voltage is connected in parallel to a first recovery diode D ₇ having a small reverse recovery loss, and the forward current before the occurrence of the reverse recovery is cut off by the MOSFET Q _32. are doing. Thus, while avoiding the reverse recovery of the rectifier diode D _8, to reduce the loss by utilizing the low forward voltage drop, enabling the efficiency of the entire circuit.

On the other hand, the present applicant has proposed a unidirectional switch (FIG. 9A) and a bidirectional switch (FIG. 9A) in which a self-extinguishing semiconductor element and a thyristor are combined as semiconductor switches for the purpose of reducing conduction loss and operating at high speed. 9 (b)) has already been filed.
In unidirectional switch of FIG. 9 (a), _{Q 1} is a high-speed switching is possible IGBT, _{Q 2} is the forward voltage drop is very small low-voltage of MOSFET, Th is the forward voltage drop is small thyristors, 100, 100 'passing This indicates a circuit path in which a bidirectional current to be flown or interrupted flows.
Note that the bidirectional switch in FIG. 9B is equivalent to two unidirectional switches in FIG. 9A connected in antiparallel, Q _1a and Q _1b are IGBTs, and Q _2a and Q _2b are MOSFETs Th _a and Th _b are thyristors. Since the operation of the bidirectional switch can be easily inferred from the operation of the unidirectional switch described below, the description is omitted here.

FIG. 10 is a timing chart showing the operation of the unidirectional switch of FIG. 9A, in which the polarity of the voltage on the electric circuit 100 side is positive. Here, operation when, as shown at the top of FIG. 10, a unidirectional switch conducts for a period of time t ₁ ~t _5, the total current flows through the path 100 'from the path 100 via the unidirectional switch Will be described.

First, from the state where the unidirectional switch is off, the gate signal of the IGBT Q ₁ current flows through the turned ON IGBT Q ₁ at time _{t 1,} the thyristor at time _{t 2} has elapsed on delay time _{t don} Th and MOSFET gate signal of Q ₂ is turned ON.
Thus, the IGBT Q _1, the period of time _t 1 ~t _2, current flows, the time _{t 2} later, the current is commutated to the series circuit from the IGBT Q ₁ and thyristor Th and the MOSFET Q _2. The gate signal of the MOSFET Q ₂ is turned OFF at time _{t 3,} subsequent current through the thyristor Th becomes less holding current at time _{t 4,} current flowing in the series circuit of the thyristor Th and the MOSFET Q ₂ IGBT commuted to Q _1. The gate signal of IGBT Q ₁ Since the OFF from time _{t 3} to time _{t 5} after the elapse of the off delay time _{t doff,} the IGBT Q ₁ period time _t 4 ~t _5, current flows.

In this prior, during conduction of the unidirectional switch is mainly flowed through the current through the low forward voltage drop thyristor Th and MOSFET Q _2, then the IGBT Q ₁ side to turn OFF the MOSFET Q ₂ It cuts off after commutating the current. Here, the period in which current flows in IGBT _{Q 1,} i.e. the time _{t 1 ~t 2, t 4 ~t} 5 is very short, most of the total current over time _t 2 ~t ₄ of thyristor Th and the MOSFET Q ₂ Since the current flows through the series circuit, conduction loss can be reduced.
In particular, at the timing of OFF the MOSFET Q ₂ is IGBT Q ₁ is turned ON, since the MOSFET Q ₂ are not only the voltage of about several [V] is applied, using a low-voltage and low-cost device for MOSFET Q ₂ It can be, an increase in the conduction loss also connected in series MOSFET Q ₂ to the thyristor Th is negligible.

JP 2009-81969 A ([0010] to [0014], FIG. 1 and the like) JP 2011-135758 A ([0030] to [0037], FIG. 1 and the like) Japanese Patent No. 6288534 ([0028] to [0038], FIGS. 1 and 2)

In the conventional technique described in Patent Document 1, since a current flows through both the IGBT and the MOSFET, conduction loss is large. On the other hand, in each of the switches shown in FIGS. 9A and 9B, the conduction loss can be reduced.
Here, the thyristors in FIGS. 9A and 9B generally have a short-time overcurrent withstand capability of about 10 times the rating. On the other hand, in the IGBT in which the current is commutated with the thyristor, the collector current is saturated at about five times the rated current as shown in the saturation current characteristic shown in FIG. The voltage between the collector and the emitter may rise and reach a maximum equivalent to the power supply voltage. Therefore, as shown in FIG. 10 in this current range, if the IGBT Q ₁ is turned OFF MOSFET Q ₂ in a state in which ON, and commutates the current of the thyristor Th the IGBT Q ₁ side, the MOSFET Q ₂ there can lead is applied to the overvoltage breakdown - is (emitter voltage collector of IGBT Q ₁₎ voltage exceeding the breakdown voltage significantly.

  Therefore, an object of the present invention is to solve the problem that even when a current flowing through a thyristor in an overcurrent region is commutated to a self-extinguishing type semiconductor device such as an IGBT, the current is not saturated and the commutation source device is destroyed by overvoltage. It is another object of the present invention to provide a bidirectional switch circuit which prevents the occurrence of such a problem.

In order to solve the above-mentioned problem, the invention according to claim 1 is a bidirectional switch circuit that allows a bidirectional current to flow and cuts off by an operation of a semiconductor switching element, and is inserted into an electric path through which the bidirectional current flows. In a bidirectional switch circuit,
A first unidirectional switch unit formed by serially connecting a first thyristor and a first self-extinguishing semiconductor device in a forward direction, and a second thyristor and a second self-extinguishing semiconductor device in order. And a second unidirectional switch unit connected in series in the direction, and connected in anti-parallel to form an anti-parallel circuit,
While connecting the anti-parallel circuit in series with the electric circuit,
Both ends of the anti-parallel circuit are respectively connected to an AC input terminal of a diode bridge, and a third self-extinguishing type semiconductor element constituting a third unidirectional switch is connected between the DC output terminals of the diode bridge in the forward direction. Characterized in that it is connected to

  According to a second aspect of the present invention, in the bidirectional switch circuit according to the first aspect, the third unidirectional switch section is constituted by a single third self-extinguishing type semiconductor element. I do.

  According to a third aspect of the present invention, in the bidirectional switch circuit according to the first aspect, the third unidirectional switch section is configured by connecting a plurality of the third self-extinguishing type semiconductor elements in series. It is characterized by the following.

  According to a fourth aspect of the present invention, in the bidirectional switch circuit according to any one of the first to third aspects, a capacitor is connected in parallel to the third self-extinguishing type semiconductor element.

  According to a fifth aspect of the present invention, in the bidirectional switch circuit according to any one of the first to fourth aspects, the third thyristor and the second thyristor receive the third current with respect to a short-time allowable current. The third self-extinguishing type semiconductor element is selected so that the output current of the self-extinguishing type semiconductor element does not saturate.

  The invention according to claim 6 is the bidirectional switch circuit according to claim 5, wherein the continuous current capacity of the first thyristor and the second thyristor is smaller than that of the third self-extinguishing type semiconductor element. The third self-extinguishing type semiconductor element is selected so that the continuous current capacity becomes approximately twice or more.

According to a seventh aspect of the present invention, in the bidirectional switch circuit according to any one of the first to sixth aspects, the third self-turn-off semiconductor element is an IGBT.
The invention according to claim 8 is the bidirectional switch circuit according to any one of claims 1 to 7, wherein the first self-extinguishing semiconductor device and the second self-extinguishing semiconductor device are provided. Are low-breakdown-voltage MOSFETs.

According to the present invention, even when the currents of the first and second thyristors are commutated to the third self-extinguishing semiconductor device such as an IGBT, the output current of the self-extinguishing semiconductor device is not saturated. By considering the current capacity and the like, it is possible to prevent the first and second self-extinguishing type semiconductor elements such as MOSFETs connected in series with the thyristor from being damaged by overvoltage.
If a capacitor is connected in parallel to the third self-extinguishing type semiconductor element, so-called soft switching becomes possible.

1 is a circuit diagram illustrating a first embodiment of the present invention. 4 is a timing chart illustrating an operation of the first exemplary embodiment of the present invention. FIG. 3 is a circuit diagram illustrating an operation of the first exemplary embodiment of the present invention. FIG. 4 is an explanatory diagram of a reverse bias safe operation area of the IGBT. It is a circuit diagram showing a second embodiment of the present invention. FIG. 9 is a circuit diagram of a conventional technique described in Patent Document 1. FIG. 11 is a circuit diagram of a conventional technique described in Patent Document 2. FIG. 11 is a circuit diagram of a conventional technique described in Patent Document 3. FIG. 2 is a diagram showing a unidirectional switch circuit and a bidirectional switch circuit according to the prior application. 6 is a timing chart showing the operation of the unidirectional switch circuit according to the prior application. FIG. 4 is a diagram illustrating a saturation current characteristic of the IGBT. It is a figure showing a modification of the bidirectional switch circuit concerning a prior application.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a circuit diagram showing a bidirectional switch circuit according to the first embodiment of the present invention.
In the first embodiment, similarly to FIG. 9 (b), the thyristor Th _a and a low-voltage first unidirectional switch portion _{S a} of the MOSFET Q _2a formed by series connection of the thyristor Th _b and the low-voltage the MOSFET and Q _2b and a second unidirectional switch section _{S b} formed by serially connected are connected in reverse parallel, these anti-parallel circuit is inserted between the tracks 100, 100 '.

Further, paths 100, 100 '(both ends of the reverse parallel circuit) are connected to the AC input terminal of the diode bridge DB to a diode _D 1 to D _4. The DC output terminals of the diode bridge DB, a collector of IGBT Q ₁ constituting a third unidirectional switch portion _{S c,} emitter is connected to the capacitor C is connected in parallel to the IGBT Q _1.
As described above, the bidirectional switch circuit according to the present embodiment is connected in series to the electric circuits 100 and 100 'to flow and cut off bidirectional current.

Here, the IGBT Q ₁ uses a single element having a large current capacity with respect to the short-time allowable current of the thyristors Th _a and Th _b , or connects a plurality of IGBTs in parallel to each other. It is necessary to keep the collector current from saturating.
As described above, the thyristor _Th a, the use of IGBT Q ₁ current capacity is large with respect short allowable current of Th _b is, for example, a thyristor _Th a, the continuous current capacity of Th _b, more than double It refers to the use of IGBT Q ₁ with a continuous current capacity. In other words, the thyristor Th _a, a short overcurrent Th _b is 10 times the rated current, the saturation current of the IGBT Q ₁ as 10 times the rated current, so that these short overcurrent and the saturation current matches An IGBT and a thyristor having a high rated current may be selected.

Next, the operation of the first embodiment will be described with reference to FIGS.
2 is a timing chart showing the operation as a unidirectional switch, FIGS. 3 (a), 3 (b) and 3 (c) are circuit diagrams in which a current path is superimposed on FIG. 1, and FIG. 4 is a reverse bias safe operation of the IGBT. It is a figure showing an area.
2, the time _{t 11} before the time _{t 16} subsequent switch is in an interrupted state, the period of time _t 11 _{~t 16} is conductive the switch.

First, the gate signal turns ON the IGBT Q ₁ at time _{t 11,} begins to flow current of IGBT Q _1. The current path from the electric circuit 100 to the electric circuit 100 'at this time is as shown in FIG.
Thereafter, the gate signal of the MOSFET Q _2a is turned ON at time _{t 12,} further time gate signal turns ON the thyristor Th _a in _{t 13,} the time _{t 11} is current flowing through the IGBT Q ₁ the time _{t 13} Thereafter thyristor commutated to the series circuit of the Th _a and the MOSFET Q _2a. Therefore, the main current path is as shown in FIG. The time _{t 13} gate signals of IGBT Q ₁ also thereafter for remains ON, the slight current flows in IGBT Q _1.

Then, the gate signal of the thyristor Th _a is turned OFF, by the gate signal of the MOSFET Q _2a is OFF in the subsequent time _{t 14,} the thyristor Th _a current flowing in the series circuit of the MOSFET Q _2a again IGBT commuted to Q ₁ side. Although immediately after the time _{t 14} flows slightly current in the series circuit of the thyristor Th _a and MOSFET Q _2a, most of the current flows in the route of Figure 3 (a).
Thereafter, OFF gate signals IGBT Q ₁ at time _{t 15} Then, the current IGBT Q ₁ is almost 0 to rapidly decrease. Period from time t ₁₅ to time t _16, by charging the capacitor C it current flowing through the IGBT Q ₁ until commutated to the capacitor C side, raising the voltage V to approximately the power supply voltage. The main current path in the time _t 15 _{~t 16} is as shown in Figure 3 (c).

_{T 1} is a period in which current flows in IGBT Q ₁ when starting conduction of the switches in the timing chart of FIG. 2, _{T 2} is a period in which current flows in the series circuit of the thyristor Th _a and MOSFET Q _2a during conduction, _{T 3} is switch a period in which current flows in the IGBT Q ₁ before blocking. The periods T ₁ and T ₃ are short, for example, about 100 [μs].
The voltage of the voltages _{V 1} in FIG. 2 is a power supply that is connected to the path 100 (not shown), voltage _{V 2} is diode _D 1 of the the diode bridge DB, _{D 4} and the sum of the forward voltage drop of IGBT Q ₁ , the voltage _{V 3} to the sum of the forward voltage drop of the thyristor Th _a and MOSFET Q _2a, corresponding respectively.

2, the capacitor C at time _{t 15} IGBT Q ₁ is turned off are fully discharged, the voltage V (= _{V 2)} at both ends voltage or 5 for extremely small, IGBT Q ₁ is a soft switching operation I do.
Here, as shown in FIG. 4, safely operable collector when IGBT Q ₁ is turned off - the relationship between the emitter voltage and the collector current is known as a reverse bias safe operating area (RBSOA), General A typical safe operation area is a square characteristic hatched with oblique lines. In other words, many commercially available IGBTs are designed such that the element can withstand the voltage-current locus at the time of turn-off even when passing the rated voltage and the rated current or a point several times the rated voltage and the rated current.

However, in the present embodiment, it premised soft switching by the action of the parallel connected capacitors C in IGBT Q _1, voltage of the device if ensure that the maximum voltage and the maximum current is not applied simultaneously, relieving the tolerance of the current Therefore, a low-cost element having a narrow reverse-bias safe operation area, such as a hatched portion of the vertical line in FIG. 4, can be used.

Note that the idea of performing IGBT soft switching using a capacitor is also applicable to the bidirectional switch according to the prior application. For example, FIG. 12 shows an example in which a capacitor C is connected in parallel to the bidirectional switch shown in FIG. 9B. Also in this circuit, the IGBTs Q _1a and Q _1b can be soft-switched by the action of the capacitor C. is there.
However, in the circuit of Figure 12, _IGBT Q _1a, since after the turn-off of _{Q 1b} also through the capacitor C path 100, 100 'alternating current continues to flow between, as possible capacitance value of the capacitor C to prevent this small It is desirable to do. In contrast, in the circuit of Figure 1 according to this embodiment, the switch time t ₁₆ subsequent 2 to be cut-off state and no current flows have been charged in the capacitor C is the peak voltage (power supply voltage V ₁₎ There is no problem even if the capacitance value of the capacitor C is large to some extent.

In the present embodiment, when the switch is operated from cut-off → conduction → cut-off as shown in FIG. 2, the periods T ₁ and T ₃ in which current flows through the IGBT Q ₁ are very short. In addition, when the switches are continuously turned on, the gate signals of the thyristors Th _a and Th _b are always ON, and the periods T ₁ and T ₃ do not exist originally. In other words, the loss due to the forward voltage drop of the diode D _1, D ₄ and IGBT Q ₁ corresponding to the voltage V ₂ in FIG. 2 because it is not intended that occurs constantly, it is possible to prevent a reduction and heat generation efficiency.

Further, in this embodiment, 'since you have connected the IGBT Q ₁ via the diode bridge DB from path 100, 100' path 100,100 IGBT Q by rectifying the bidirectional current through a diode bridge DB ₁ can be flowed. As a result, the number of relatively expensive IGBTs is halved compared to the bidirectional switch circuit of FIG. 9B, so that the cost can be reduced.
Although the operation the above description is of the case where the current flows from the path 100 side, when the current flows from path 100 'side, the thyristor Th _a in FIG. 2 is a Th _b, MOSFET Q _2a is there is no change in the basic operation in just replace each Q _2b.

Next, FIG. 5 is a circuit diagram showing a second embodiment of the present invention. This second embodiment, the third unidirectional switching unit _{S d} which is connected between the DC output terminals of the diode bridge DB is, IGBT Q _1a of the plurality (e.g., four), _{Q 1b,} Q _1c, the _{Q 1d} It is composed of a series circuit. Capacitors C _a , C _b , C _c , and C _d having the same capacitance are all connected between the collectors and emitters of the IGBTs Q _1a , Q _1b , Q _1c , and Q _1d , respectively.
The other configuration is the same as that of the first embodiment of FIG.

The second embodiment takes into consideration the increase in the withstand voltage of the bidirectional switch circuit.
In other words, when increasing the breakdown voltage of a circuit, a high breakdown voltage thyristor can be obtained relatively easily, but a high breakdown voltage IGBT such as an element having a breakdown voltage of 3.3 kV or more is expensive. Moreover, the types are limited. Accordingly, constitute a relatively inexpensive and easy withstand voltage 1.2 [kV] of about IGBT availability, multiple between DC output terminals of the diode bridge DB, a third unidirectional switching unit S _d connected in series Thereby, a desired withstand voltage is obtained.
Capacitors C _a , C _b , C _c , and C _d connected in parallel to the IGBTs Q _1a , Q _1b , Q _1c , and Q _1d not only enable the above-described soft switching but also enable the diode bridge DB to operate. It also functions to equalize the voltage between the collector and the emitter of each IGBT by equally dividing the DC output voltage.

1, in the embodiments shown in FIG. 5, as a self-extinguishing type semiconductor elements constituting the third unidirectional switch portion _{S c} or _{S d,} IGBT Q ₁ or _{Q 1a, Q 1b, Q 1c} , Q _Although the case where _1d is used has been described, the present invention can be applied to a case where a bipolar power transistor or MOSFET is used instead of the IGBT.
The first, second unidirectional switch portion _S a, as the self arc-suppressing semiconductor elements constituting the _{S b, MOSFET} Q _2a, may be used IGBT instead of _{Q 2b.}
Further, the thyristors Th _a and Th _b constituting the first and second unidirectional switch sections S _a and S _b do not need to be a single thyristor, and each is constituted by a series circuit of a plurality of thyristors and has a high withstand voltage. May be achieved.

  INDUSTRIAL APPLICABILITY The bidirectional switch circuit of the present invention is used, for example, in various switch circuits that flow and cut off bidirectional current (AC current), including a bypass circuit that switches between a normal power supply and a backup power supply in an uninterruptible power supply. can do.

Q ₁ , Q _1a , Q _1b , Q _1c , Q _1d : IGBT
Q _2a , Q _2b : MOSFET
Th _a, Th _b: thyristors _{S a, S b, S c} , S d: unidirectional switch unit DB: Diode bridge _{D 1, D 2, D 3} , D 4: Diode _{C, C a, C b,} C c , C _d : capacitors 100, 100 ′: electric circuit

Claims (8)

A bidirectional switch circuit that allows a bidirectional current to flow and cuts off by an operation of a semiconductor switching element, wherein the bidirectional switch circuit is inserted into an electric path through which the bidirectional current flows.
A first unidirectional switch unit formed by serially connecting a first thyristor and a first self-extinguishing semiconductor device in a forward direction, and a second thyristor and a second self-extinguishing semiconductor device in order. And a second unidirectional switch unit connected in series in the direction, and connected in anti-parallel to form an anti-parallel circuit,
While connecting the anti-parallel circuit in series with the electric circuit,
Both ends of the anti-parallel circuit are respectively connected to an AC input terminal of a diode bridge, and a third self-extinguishing type semiconductor element constituting a third unidirectional switch is connected between the DC output terminals of the diode bridge in the forward direction. And a bidirectional switch circuit connected to the switch. The bidirectional switch circuit according to claim 1,
A bidirectional switch circuit, wherein the third unidirectional switch section is constituted by a single third self-extinguishing type semiconductor element. The bidirectional switch circuit according to claim 1,
A bidirectional switch circuit, wherein the third unidirectional switch section comprises a plurality of the third self-extinguishing semiconductor elements connected in series. The bidirectional switch circuit according to any one of claims 1 to 3,
A bidirectional switch circuit, wherein a capacitor is connected in parallel to the third self-extinguishing type semiconductor element. The bidirectional switch circuit according to any one of claims 1 to 4,
The third self-extinguishing type semiconductor element is selected such that the output current of the third self-extinguishing type semiconductor element is not saturated with respect to the short-time allowable current of the first thyristor and the second thyristor. A bidirectional switch circuit. The bidirectional switch circuit according to claim 5,
The third self-arc-extinguishing type semiconductor device is configured such that the continuous current capacity of the third self-extinguishing type semiconductor device is approximately twice or more the continuous current capacity of the first thyristor and the second thyristor. A bidirectional switch circuit characterized by selecting a semiconductor element. The bidirectional switch circuit according to any one of claims 1 to 6,
A bidirectional switch circuit, wherein the third self-extinguishing type semiconductor device is an IGBT. The bidirectional switch circuit according to any one of claims 1 to 7,
A bidirectional switch circuit, wherein the first self-extinguishing semiconductor device and the second self-extinguishing semiconductor device are low breakdown voltage MOSFETs.

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