JP3383571B2 - Semiconductor element driving circuit and power conversion device using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor element drive circuit and a power conversion device using the same, and particularly, to a good protection against an overvoltage accompanying current limitation without increasing the load of the current limitation circuit. The present invention also relates to a semiconductor element drive circuit and a power conversion device using the same, in which a current can be limited without concentration of a voltage on a specific semiconductor element when an overcurrent occurs.

[0002]

2. Description of the Related Art Generally, semiconductor elements for electric power have been widely used as main switching elements of electric power converters such as inverters for driving electric motors, uninterruptible power supplies and frequency converters.

In particular, among semiconductor devices for electric power, IG
BT is widely used for industrial purposes because it has the advantages of large current and insulated gate. In recent years,
IPM (Int) with added value for IGBT and drive circuit
The development of elligent Power Module) is also becoming popular.

FIG. 8 is a circuit diagram showing an example of the configuration of a drive circuit (current limiting drive circuit) for a semiconductor element (IGBT) having a current limiting circuit. The semiconductor element (IGB
The driving circuit of T) is described, for example, in 9.3 Power Module IPM of "Power Device / Power IC Handbook" published by Corona.

In FIG. 8, an IGBT with a current sense (hereinafter simply referred to as an IGBT) 1 which is a semiconductor element is
Collector terminal C, emitter terminal E, gate terminal G
And a sense terminal S that outputs a signal that depends on the magnitude of the current flowing through the IGBT 1 body.

On the other hand, the gate drive circuit 2 has one end connected to the gate terminal G of the IGBT 1 via the gate resistor 3 and the other end connected to the emitter terminal E of the IGBT 1.

Further, a series circuit of a diode 4 and a transistor 5 is connected between the gate terminal G and the emitter terminal E of the IGBT 1 as shown in the drawing, and further connected between the base terminal and the emitter terminal of the transistor 5. Is connected to the detection resistor 6.

The current-limited drive circuit 18 is constructed from the portion surrounded by the one-dot chain line in the figure. In addition,
The collector terminal C and the emitter terminal E are connected to a main circuit (not shown).

Next, the operation of the drive circuit for such a semiconductor element (IGBT) will be described. In FIG. 8, GBT1
Is in a conducting state when a positive voltage is applied between the gate terminal G and the emitter terminal E, and is in a blocking state when a negative voltage is applied.

A drive signal is supplied from the gate drive circuit 2 through the gate resistor 3 between the gate terminal and the emitter terminal. Then, the sense current IS, which is about several hundredths of the collector current IC, flows through the sense terminal S.

When the collector current IC increases and becomes an overcurrent, a large sense current IS flows. This sense current IS is shunted to the base terminal of the transistor 5 and the detection resistor 6, so that the transistor 5 is activated and the current IT flows. Then, this current IT causes the voltage VGE between the gate terminal G and the emitter terminal E of the GBT 1 to decrease, so that the IGBT 1 is actively turned off and the collector current IC decreases.

As described above, since negative feedback is applied to the collector current IC, the collector current IC has a specific value (hereinafter,
It is saturated at the current limit value). That is, when the resistance value of the detection resistor 6 is selected to be large, the current flowing through the base terminal of the transistor 5 increases, and the current limit value becomes low. Conversely, if the resistance value of the detection resistor 6 is selected to be small,
The current limit value increases.

Incidentally, in FIG.
The same applies when replaced with ET or the like. FIG. 9: is a circuit diagram which shows the structural example of the power converter device (inverter) comprised by connecting in series several IGBT using the drive circuit with a current limitation.

In FIG. 9, only one phase of the power converter is shown. In FIG. 9, a DC voltage source 20
A power converter including a positive side arm 21 and a negative side arm 22 is connected to the DC power source, and DC power from the DC voltage source 20 is converted into AC power and supplied to a load 23 such as an electric motor.

Further, at least two positive arm 21 and negative arm 22 (three in the figure) are connected in series to each other, and IGBTs 1A to 1C and IGBT1D to.
1F and these IGBT1A-1C, and IGBT1
Current limiting drive circuit 18A connected to each of D to 1F
To 18F, the current limiting drive circuits 18A to 18F have the same configuration as the current limiting drive circuit 18 of FIG.

That is, by connecting a plurality of IGBTs in series with each other, a power converter having a voltage higher than the withstand voltage of the single IGBT can be constructed. Next, the operation of the power converter will be described.

In FIG. 9, drive circuits 18A to 18C with current limiting for the positive arm 21, that is, GBTs 1A to 1C.
Is in a conductive state, the negative arm 22, that is, IGBT1D to
When the 1F current limiting drive circuits 18D to 18F are set in the blocking state, the potential of VP can be output to the load 23.

On the contrary, the positive arm 21 is blocked,
When the negative arm 22 is made conductive, a VN potential can be output to the load 23. In this way, by supplying the potentials of VP and VN to the load 23 at arbitrary timing, the current flowing through the load 23 is controlled.

When an overcurrent flows through the positive arm 21, the current limiting drive circuits 18A to 18C act to limit the current as in the case of FIG. 8 described above. Further, the same applies to the negative arm 22.

FIG. 10 is a circuit diagram showing a configuration example of a drive circuit of a semiconductor element (IGBT) having an overvoltage protection circuit, and the same elements as those in FIG. 8 are designated by the same reference numerals.
In FIG. 10, the IGBT 15, which is a semiconductor element, includes a collector terminal C, an emitter terminal E, and a gate terminal G.

On the other hand, the gate drive circuit 2 has one end connected to the gate terminal G of the IGBT 15 via the gate resistor 3 and the other end connected to the emitter terminal E of the IGBT 15.

Further, between the collector terminal C and the gate terminal G of the IGBT 15, an overvoltage protection circuit 16 constituted by connecting a Zener diode 7, a diode 8 and a resistor 9 in series as shown in the drawing is connected. ing.

The collector terminal C and the emitter terminal E
Are connected to a main circuit (not shown). Next, the operation of such a semiconductor element (IGBT) drive circuit will be described.

In FIG. 10, when an overvoltage occurs between the collector terminal C and the emitter terminal E while the IGBT 15 is off, the Zener diode 7, the diode 8, the resistor 9, the gate resistor 3, A current flows to the emitter terminal E via the gate drive circuit 2.

Then, this current causes the voltage VGE between the gate terminal G and the emitter terminal E of the GBT 15 to rise,
The IGBT 15 is actively turned on. Thereby, the energy for generating the overvoltage is consumed by the IGBT 15, and the overvoltage can be suppressed.

[0026]

By the way, in the drive circuit with current limitation shown in FIG. 8, the overvoltage may occur in the IGBT 1 due to the action of the current limitation.
That is, as shown in FIG. 9, Is connected in series are connected to each other.
When current limiting is performed on the GBTs 1A to 1C and the IGBTs 1D to 1F, and if the current limiting values of the current limiting circuits vary, the IG having the lowest current limiting value is obtained.
Only BT acts to limit the current. as a result,
In this case, an overvoltage exceeding the withstand voltage is applied to the specific IGBT.

On the other hand, the current limiting circuit of FIG.
When the overvoltage protection circuit of 0 is used together, the current limiting circuit and the overvoltage protection circuit operate in the same manner when an overvoltage occurs due to the action of the current limiting. At this time, the overvoltage protection circuit must flow a current equivalent to the current passed by the current limiting circuit. In this case, a large current flows through the overvoltage protection circuit, which increases the load on the current limiting circuit and the overvoltage protection circuit.

An object of the present invention is to provide a drive circuit for a semiconductor device, which can favorably protect against an overvoltage caused by current limitation without increasing the load on the current limitation circuit.

Further, an object of the present invention is to limit the current in a power converter in which at least two or more semiconductor elements are connected in series to each other without causing the voltage to concentrate on a specific semiconductor element when an overcurrent occurs. It is to provide a possible power converter.

[0030]

In order to achieve the above object, according to the invention of claim 1, a signal is output which depends on at least a current flowing through a collector terminal, an emitter terminal, a gate terminal and a semiconductor element body. In a drive circuit with a current limit, which is used by connecting to a semiconductor element having a sense terminal and which limits a current flowing through the semiconductor element body at a predetermined current limit value based on an output signal from the sense terminal, a collector terminal and A first overvoltage detection unit connected between the emitter terminal and the first terminal, which operates when the voltage between the terminals becomes equal to or higher than an arbitrary first voltage in consideration of the breakdown voltage of the semiconductor element body; And a current limit relaxation means for increasing the current limit value by operation.

Therefore, in the semiconductor element drive circuit according to the first aspect of the present invention, the overvoltage between the collector terminal and the emitter terminal, that is, the withstand voltage of the semiconductor element body is taken into consideration while the current limiting circuit is operating. When a voltage higher than the voltage is generated, the current limit value is increased,
Since the current limit is relaxed, the occurrence of overvoltage can be relaxed.

As a result, it becomes possible to satisfactorily protect against the overvoltage caused by the current limitation without increasing the load on the current limiting circuit 19. According to a second aspect of the present invention, in the semiconductor element drive circuit according to the first aspect of the present invention, a second voltage higher than the first voltage is applied between the collector terminal and the gate terminal. An overvoltage protection circuit having an overvoltage detection means is connected.

Therefore, in the semiconductor element drive circuit according to the second aspect of the present invention, when current limitation is applied,
In addition to the same effect as in the case of the invention of claim 1, the overvoltage protection circuit can prevent the overvoltage from occurring even when the current is not limited.

Further, since the overvoltage protection circuit and the current limiting circuit do not operate at the same time, the burdens on the current limiting circuit and the overvoltage protecting circuit do not increase. Further, in the invention of claim 3, in the semiconductor element drive circuit of the invention of claim 1, the voltage is lower than the first voltage between the connection point of the first overvoltage detection means and the emitter terminal and the gate terminal. An overvoltage protection circuit including a third overvoltage detection unit that operates at a third voltage is connected.

Therefore, in the semiconductor element drive circuit according to the third aspect of the invention, in addition to the same operation as the case of the first aspect of the invention, in the case of the second aspect of the invention, two The required high-voltage overvoltage detecting means can be replaced with two types of high withstand voltage and low withstand voltage, that is, only one high-voltage overvoltage detecting means is required, so that the circuit configuration can be downsized. .

On the other hand, in the invention of claim 4, at least 2
In a power converter comprising a positive side arm and a negative side arm each composed of one or more semiconductor elements connected in series with each other, the invention according to any one of claims 1 to 3 can be applied to each semiconductor element. Connect the drive circuits respectively.

Therefore, in the power converter of the fourth aspect of the present invention, even if the current limiting values of the current limiting circuits vary, the voltage is applied to the specific semiconductor element having the lowest current limiting value when the overcurrent occurs. The current can be limited without being concentrated.

As a result, even in a power converter in which at least two or more semiconductor elements are connected in series with each other, it is possible to limit the current without concentration of voltage on a particular semiconductor element when an overcurrent occurs.

Further, in the invention of claim 5, at least 2
In a power converter that includes a positive side arm and a negative side arm each composed of three or more semiconductor elements connected in series, and outputs at least three or more levels of potential, each of the semiconductor elements is provided with the above-mentioned claims 1 to 3. The drive circuit of the invention of any one of 3 is connected. Therefore,
Also in the power converter of the invention of claim 5, the same operation as in the case of the invention of claim 4 can be achieved.

[0040]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. (First Embodiment: Corresponding to Claim 1) FIG. 1 is a circuit diagram showing a configuration example of a drive circuit for a semiconductor element (IGBT) according to the present embodiment, and the same elements as those in FIG. Will be omitted and the description will be omitted, and only different parts will be described here.

That is, the semiconductor element (I
As shown in FIG. 1, the drive circuit of the (GBT) has a first circuit between the collector terminal C and the emitter terminal E of the drive circuit of the semiconductor device (IGBT) including the current limiting circuit of FIG.
Zener diode 10 and resistor 1 which are the overvoltage detection means of
2 and a resistor 13 are connected in series.

Here, the breakdown voltage of the Zener diode 10 is
It is set to operate when the voltage exceeds an arbitrary first voltage in consideration of the withstand voltage of the IGBT1 main body (maximum withstand voltage at which the IGBT1 main body is not destroyed).

The detection resistor 6 is formed by connecting two detection resistors 6A and 6B in series. Further, a transistor 14 which is a means for relaxing current limitation is added, the collector terminal of the transistor 14 is connected to the connection point of the detection resistors 6A and 6B, and the base terminal is connected to each resistor 1.
Connect to the connection point of 2 and 13 and set the emitter terminal to each resistor 6
It is connected to the connection point of B and 13.

A portion 17 surrounded by a dashed line in the drawing constitutes a current limiting drive circuit, and a portion 19 surrounded by a dashed line in the drawing constitutes a current limiting circuit. Next, the operation of the drive circuit for the semiconductor element (IGBT) of the present embodiment configured as described above will be described.

In FIG. 1, the sense current IS flows through the series circuit of the detection resistors 6A and 6B and the base terminal of the transistor 5. That is, the detection resistor 6 of FIG.
Is the sum of the resistance values of the detection resistors 6A and 6B.

When the voltage between the collector terminal C and the emitter terminal E of the GBT 1 becomes higher than the withstand voltage of the Zener diode 10, a current flows through the Zener diode 10, the resistor 12 to the resistor 13 and the base terminal of the transistor 14.

Then, the transistor 14 becomes conductive and the resistor 6B is short-circuited. As a result, the resistance value of the detection resistor 6 in FIG. 8 described above becomes the resistance value of the detection resistor 6A, and the resistance value decreases. That is, when the Zener diode 10 operates due to overvoltage or the like, the resistance value of the detection resistor decreases, so that the current limit value increases (increases).

In this manner, when the current limiting circuit 19 is operating and an overvoltage resulting from the current limiting occurs between the collector terminal C and the emitter terminal E, the current limiting value is increased. As a result, the current limitation is relaxed, and the occurrence of overvoltage can be mitigated.

As described above, in the drive circuit for the semiconductor device (IGBT) of this embodiment, an overvoltage, that is, a semiconductor, is applied between the collector terminal C and the emitter terminal E while the current limiting circuit 19 is operating. When a voltage equal to or higher than the voltage considering the breakdown voltage of the element body is generated, the current limit value is increased and the current limit is relaxed, so that the occurrence of overvoltage can be mitigated.

As a result, it becomes possible to satisfactorily protect against the overvoltage caused by the current limitation without increasing the load on the current limiting circuit 19. (First Modification of First Embodiment) FIG. 2 is a circuit diagram showing a configuration example of a drive circuit for a semiconductor element (IGBT) according to the present embodiment, and the same elements as those in FIG. Will be omitted and the description will be omitted, and only different parts will be described here.

That is, the semiconductor element (I
In the driving circuit of the GBT), the transistor 14 is connected in parallel to the detection resistor 6B in FIG. 1, but the transistor 14 is connected in parallel to the detection resistor 6A as shown in FIG. I am trying.

Also in the semiconductor element (IGBT) drive circuit of the present embodiment, the collector terminal C is operated by the same operation as in the case of FIG. 1 while the current limiting circuit 19 is operating.
When an overvoltage between the emitter terminal E and the emitter terminal E, that is, a voltage equal to or higher than the voltage considering the withstand voltage of the semiconductor element body is generated, the current limit value is increased and the current limit is relaxed. can do.

(Second Modification of First Embodiment) FIG.
FIG. 2 is a circuit diagram showing a configuration example of a drive circuit for a semiconductor element (IGBT) according to the present embodiment, the same elements as those in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted. Describe.

That is, the semiconductor element (I
As shown in FIG. 2, the drive circuit of the (GBT) has a structure in which a resistor 11 is connected to the emitter terminal side of the transistor 5.

Also in the semiconductor element (IGBT) drive circuit of the present embodiment, the collector terminal C is operated by the same operation as in the case of FIG. 1 while the current limiting circuit 19 is operating.
When an overvoltage between the emitter terminal E and the emitter terminal E, that is, a voltage equal to or higher than the voltage considering the withstand voltage of the semiconductor element body is generated, the current limit value is increased and the current limit is relaxed. can do.

(Second Embodiment: Corresponding to Claim 2) FIG. 4 is a circuit diagram showing a configuration example of a drive circuit for a semiconductor element (IGBT) according to the present embodiment. Are denoted by the same reference numerals and the description thereof will be omitted, and only different portions will be described here.

That is, the semiconductor element (I
As shown in FIG. 4, the drive circuit of the (GBT) includes a Zener diode 7, a diode 8 and a resistor 9, which are second overvoltage detecting means, between the collector terminal C and the gate terminal G as shown in FIG. An overvoltage protection circuit 16 configured by being connected in series is connected and configured.

Here, the breakdown voltage of the Zener diode 7 is set to operate at a second voltage higher than the set voltage (first voltage) of the Zener diode 10. Next, the operation of the drive circuit for the semiconductor element (IGBT) of the present embodiment configured as described above will be described.

In FIG. 2, when the current is limited by the current limiting circuit 19, the same operation as in the case of the first embodiment is achieved. In addition, the current limiting circuit 19
Even when the current limitation is not applied due to, the overvoltage is suppressed by the action of the overvoltage protection circuit 16 with respect to the normal overvoltage.

That is, when an overvoltage occurs between the collector terminal C and the emitter terminal E while the IGBT 15 is off, the Zener diode 7, the diode 8, the resistor 9, the gate resistor 3 and the gate drive from the collector terminal C. A current flows through the circuit 2 to the emitter terminal E.

Then, due to this current, the voltage VGE between the gate terminal G and the emitter terminal E of the GBT 15 rises,
The IGBT 15 is actively turned on. Thereby, the energy for generating the overvoltage is consumed by the IGBT 15, and the overvoltage can be suppressed.

In the above, the Zener diode 7
Since the withstand voltage of is higher than that of the Zener diode 10,
The overvoltage protection circuit 16 does not operate when the current limiting circuit 19 is operating.

In this way, since the overvoltage protection circuit 16 does not act simultaneously with the current limiting circuit 19, the load on the current limiting circuit 19 and the overvoltage protection circuit 16 can be reduced.

As described above, in the semiconductor element (IGBT) drive circuit according to the present embodiment, when the current is limited, the overvoltage is generated in the same manner as in the case of the first embodiment. The overvoltage protection circuit 16 can prevent the occurrence of overvoltage even when the current is not limited.

Further, since the overvoltage protection circuit 16 and the current limiting circuit 19 do not act at the same time, it is possible to prevent the respective loads on the current limiting circuit 19 and the overvoltage protection circuit 16 from increasing.

(Third Embodiment: Corresponding to Claim 3) FIG. 5 is a circuit diagram showing a configuration example of a drive circuit for a semiconductor element (IGBT) according to the present embodiment. Are denoted by the same reference numerals and the description thereof will be omitted, and only different portions will be described here.

That is, the semiconductor element (I
As shown in FIG. 5, the drive circuit of the (GBT) has a Zener diode 2 serving as a third overvoltage detecting unit between the connection point of the Zener diode 10 and the resistor 12 and the gate terminal G.
5, the diode 8 and the resistor 9 are connected in series to each other as shown in the figure, and an overvoltage protection circuit 26 is connected.

Here, the breakdown voltage of the Zener diode 25 is
The Zener diode 10 is set to operate at a third voltage that is sufficiently lower than the set voltage (first voltage). Next, the operation of the drive circuit for the semiconductor element (IGBT) of the present embodiment configured as described above will be described.

In FIG. 5, when the current is limited by the current limiting circuit 19, the zener diode 10 of the current limiting circuit 19 detects the overvoltage by the same operation as in the case of the first embodiment. To do.

For a normal overvoltage, the series circuit of the Zener diode 10 and the Zener diode 25 detects the overvoltage. The other operations are the same as in the case of the second embodiment, so
The description is omitted here.

In this way, the Zener diode 10, which is the first overvoltage detecting means, is also used for two overvoltage detections. Therefore, two high-breakdown-voltage Zener diodes required in the second embodiment are replaced. It is possible to replace the two with high withstand voltage and low withstand voltage, and it is possible to downsize the circuit configuration.

As described above, in the semiconductor element (IGBT) drive circuit according to the present embodiment, the occurrence of overvoltage can be mitigated in the same manner as in the case of the first embodiment, and the above-mentioned first embodiment is also possible. The high withstand voltage zener diode, which was required in the case of the second embodiment, can be replaced with the two high withstand voltage and low withstand voltage. It is possible to reduce the size of the configuration.

(Fourth Embodiment: Corresponding to Claim 4) FIG. 6 shows a power converter (inverter) according to the present embodiment.
10 is a circuit diagram showing an example of the configuration of FIG. 9, the same elements as those in FIG. 9 are denoted by the same reference numerals, and the description thereof will be omitted.

In FIG. 6, only one phase of the power converter is shown. That is, as shown in FIG. 6, the power converter according to the present embodiment has the positive arm 2 of FIG.
1 and I, which is a semiconductor element in the negative arm 22
The current limiting drive circuits 17A to 17 having the same circuit configuration as the current limiting drive circuit 17 in the first embodiment are provided in the GBTs 1A to 1C and the IGBTs 1D to 1F.
C and the drive circuits with current limitation 17D to 17F are connected.

Next, the operation of the power converter of the present embodiment configured as described above will be described. In FIG.
The current limiting drive circuits 17A to 17C and the current limiting drive circuits 17D to 17F perform overvoltage detection by the same operation as in the case of the first embodiment.

That is, when a current equal to or more than the current limit value flows through the IGBTs 1A to 1F, the corresponding IGBT starts the operation of limiting the current. At this time, the voltage between the collector terminal C and the emitter terminal E of the corresponding IGBT rises,
Since the current limit value rises as the voltage rises, even in the current limit in the state where the current limit drive circuits 17A to 17C and the current limit drive circuits 17D to 17F vary, As described above, the full voltage is not applied to the IGBT having the lowest current limit value.

As described above, in the power converter of the present embodiment, even if the current limiting values of the current limiting drive circuits 17A to 17C and the current limiting drive circuits 17D to 17F vary, When the current is generated, the current can be limited without the voltage being concentrated on the specific IGBT having the lowest current limiting value.

As a result, even in a power converter in which at least two or more IGBTs, which are semiconductor elements, are connected in series, it is possible to limit the current without voltage concentration at a specific IGBT when an overcurrent occurs. .

(Fifth Embodiment: Corresponding to Claim 5) FIG. 7 shows a power converter (inverter) according to the present embodiment.
7 is a circuit diagram showing an example of the configuration of FIG. 6, and the same elements as those in FIG.

Note that FIG. 7 shows an example in which the present invention is applied to a three-level power converter of the multilevel power converters capable of outputting at least three levels of potential. The multi-level power converter is described in, for example, the multi-level inverter in 13.2.3 (1) of "Power Device / Power IC Handbook" published by Corona, and it is known here. The description is omitted.

That is, as shown in FIG. 7, the power converter according to the present embodiment has the first embodiment in which the semiconductor elements IGBT1A, 1B and IGBT1C, 1D in the positive side arm and the negative side arm are mounted. The current limiting drive circuits 17A and 17B having the same circuit configuration as the current limiting drive circuit 17 in the above embodiment, and the current limiting drive circuits 17C and 17D are connected, and further two DC voltage sources 20 and the respective IGBTs 1A and 1B are connected. , And IGBT1C, 1
Two diodes 24 are connected between D and D as shown in the figure.

Next, the operation of the power converter of the present embodiment configured as described above will be described. In FIG.
In the current-limited drive circuits 17A, 17B and the current-limited drive circuits 17C, 17D, due to the same operation as in the case of the fourth embodiment, even in the case of overcurrent through a plurality of IGBTs connected in series, Each IGBT 1A,
The current can be limited without generating an overvoltage in 1B and 1C and 1D.

As described above, in the power converter of the present embodiment, as in the case of the fourth embodiment, the current limiting drive circuits 17A and 17B and the current limiting drive circuits 17C and 17D are included. Even if the current limit value varies, when the overcurrent occurs, the specific I value with the lowest current limit value
The current can be limited without the voltage being concentrated on the GBT.

As a result, even in a power converter in which at least two or more IGBTs, which are semiconductor elements, are connected in series, it is possible to limit current when overcurrent occurs, without voltage concentration on a particular IGBT. .

(Other Embodiments) (a) In each of the above embodiments, the current limiting circuit 19 is
Although the case where the IGBT 1 and the gate drive circuit 2 are connected has been described, the present invention is not limited to this, and the IGBT 1 may be incorporated in the IGBT module or the gate drive circuit 2.

(B) In each of the above embodiments, both or one of the transistor 5 and the transistor 14 is F.
Even if it is replaced with ET, it is possible to apply the present invention in the same manner and obtain the same effect as the above.

(C) In each of the above embodiments, the case where the IGBT is used as the semiconductor element has been described, but the present invention is not limited to this, and the present invention is also applicable to the case where another semiconductor element such as FET is used as the semiconductor element. Can be similarly applied to obtain the same effect as the above.

(D) In each of the fourth and fifth embodiments, each IGBT, which is a semiconductor element, has a current limiting circuit having a circuit configuration similar to that of the current limiting drive circuit 17 in the first embodiment. Although the case of connecting the respective drive circuits with each other has been described, the present invention is not limited to this, and each IGBT which is a semiconductor element is provided with a drive circuit having a circuit configuration similar to that of the drive circuit according to the second or third embodiment. Also in the case of connection, it is possible to apply the present invention in the same manner and obtain the same effects as the above.

[0089]

As described above, according to the semiconductor element drive circuits of the first to third aspects of the present invention, the load on the current limiting circuit is not increased with respect to the overvoltage accompanying the current limiting. It becomes possible to perform good protection.

Further, according to the power converters of the inventions of claims 4 and 5, even in a power converter in which at least two semiconductor elements are connected in series with each other, a specific semiconductor element is not generated when an overcurrent occurs. It becomes possible to limit the current without concentration of the voltage.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a first embodiment of a drive circuit for a semiconductor device according to the present invention.

FIG. 2 is a circuit diagram showing another configuration example of the semiconductor element drive circuit according to the first embodiment.

FIG. 3 is a circuit diagram showing another configuration example of the semiconductor element drive circuit according to the first embodiment.

FIG. 4 is a circuit diagram showing a second embodiment of a drive circuit for a semiconductor device according to the present invention.

FIG. 5 is a circuit diagram showing a third embodiment of a semiconductor element drive circuit according to the present invention.

FIG. 6 is a circuit diagram showing a fourth embodiment of a semiconductor element drive circuit according to the present invention.

FIG. 7 is a circuit diagram showing a fifth embodiment of a semiconductor element drive circuit according to the present invention.

FIG. 8 is a semiconductor device (IGBT) including a current limiting circuit.
3 is a circuit diagram showing a configuration example of a drive circuit of FIG.

FIG. 9 is a circuit diagram showing a configuration example of a power conversion device configured by connecting a plurality of IGBTs using a current limiting drive circuit in series.

FIG. 10 is a semiconductor device (IGB having an overvoltage protection circuit;
FIG. 9 is a circuit diagram showing a configuration example of a drive circuit of T).

[Explanation of symbols]

1, 1A to 1F ... IGBT, 2 ... Gate drive circuit, 3 ... Gate resistance, 4… diode, 5 ... Transistor, 6, 6A, 6B ... Detecting resistor, 7 ... Zener diode, 8 ... Diode, 9 ... resistance, 10 ... Zener diode, 11 ... resistance, 12 ... resistance, 13 ... resistance, 14 ... Transistor, 15 ... IGBT, 16 ... Overvoltage protection circuit, 17, 17A to 17F ... Current limiting drive circuit, 18, 18A to 18F ... Current limiting drive circuit, 19 ... Current limiting circuit, 20 ... DC voltage source, 21 ... Positive arm, 22 ... Negative arm 23 ... load, 24 ... Diode, 25 ... Zener diode, 26 ... Overvoltage protection circuit.

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H02M 1/08 H02M 1/08 351 H02M 7/48 H02M 7/5387

Claims (5)

(57) [Claims] 1. A semiconductor device having at least a collector terminal, an emitter terminal, a gate terminal, and a sense terminal for outputting a signal depending on the magnitude of a current flowing through the semiconductor element body. In a drive circuit with a current limit that limits a current flowing through the semiconductor element body at a predetermined current limit value based on the output signal of, a voltage between the terminals is connected between the collector terminal and the emitter terminal. A first overvoltage detection unit that operates when the voltage exceeds an arbitrary first voltage in consideration of the breakdown voltage of the semiconductor element body; and a current limit relaxation unit that increases the current limit value by the operation of the first overvoltage detection unit. A drive circuit for a semiconductor device, comprising: 2. The semiconductor element drive circuit according to claim 1, wherein the second overvoltage detection is operated between the collector terminal and the gate terminal at a second voltage higher than the first voltage. A drive circuit for a semiconductor device, which is formed by connecting an overvoltage protection circuit including means. 3. The drive circuit for a semiconductor device according to claim 1, wherein a first voltage lower than the first voltage is provided between a connection point of the first overvoltage detection means and the emitter terminal and the gate terminal. 3. A drive circuit for a semiconductor device, which is formed by connecting an overvoltage protection circuit having a third overvoltage detection unit that operates at a voltage of 3. 4. A power converter comprising a positive side arm and a negative side arm each composed of at least two or more semiconductor elements connected in series to each other.
An electric power converter comprising the drive circuits according to any one of items 1 to 5 connected to each other. 5. A power converter in which at least two or more semiconductor elements are connected in series to each other to form a positive side arm and a negative side arm, and which outputs a potential of at least three levels, wherein: , Said claim 1 to claim 3
An electric power converter comprising the drive circuits according to any one of items 1 to 5 connected to each other.