JP2002171768A - Power converter - Google Patents

Abstract

(57) [Problem] To provide a power converter capable of reducing a required withstand voltage for a semiconductor element even with the same circuit voltage. SOLUTION: A switch series circuit in which four semiconductor switching elements are connected in series, both ends are DC voltage terminals, and an intermediate connection point is an AC voltage terminal, and two sets of capacitors are connected in series. A neutral point, a capacitor series circuit with both ends connected to both ends of the switch series circuit, two diodes connected in series, an interconnection point connected to the neutral point, and one end connected to one end of the switch series circuit. 2
Connected to the interconnection point of the semiconductor switching elements,
A diode series circuit having the other end connected to the interconnection point of the two semiconductor switching elements at the other end of the switch series circuit, wherein at least one of the semiconductor switching element and the diode is connected to the conductive substrate via the insulating substrate. In a power converter incorporated as a mounted insulated module type power semiconductor device, the insulated module type power semiconductor device is mounted on a conductive heat sink, and the conductive heat sink is connected to a neutral point.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power converter for converting DC power to AC power and AC power to DC power, and more particularly to an insulated module type power semiconductor device constituting the power converter. Regarding the implementation of.

[0002]

2. Description of the Related Art FIG. 8 shows an example of the internal structure of an insulated module type power semiconductor device. This is an example of an applied product of an insulated gate transistor (hereinafter abbreviated as IGBT), and various elements including a plurality of semiconductor switching elements 1 made of IGBT are mounted on a base 2 via an insulating substrate 3 respectively. ing. An outer peripheral portion of the base 2 is surrounded by a case 4, and a control board 31 on which a control IC 32 and the like are mounted is mounted on the upper surfaces of the plurality of elements. This control board 3
An upper case 33 is attached to the surface of the first case 33. The surfaces of the case 4 and the upper case 33 are substantially flat.
The power terminal 34 is mounted on the surface of the case 4 and the upper case 3
The signal terminal 35 is mounted on the surface of the third terminal 3.

Here, the base 2 has a function of transmitting heat of the semiconductor switching element 1 to a heat sink described later.
The insulating substrate 3 insulates the semiconductor switching element 1 from the base 2. Generally, a conductive member such as copper is used as the base 2.

FIG. 9 is a longitudinal sectional view of the insulated module type power semiconductor device shown in FIG. In order to dissipate the heat of the switching element 1 to the outside, a heat sink 5 made of aluminum or copper is adhered to the outer surface of the base 2. The solder for bonding the semiconductor switching element 1, the base 2, and the insulating substrate 3, the compounding agent for improving the conformity between the insulating substrate 3 and the heat sink 5 and improving the cooling effect, and the like are omitted. Generally, the base 2 is fixed to the heat sink 5 with screws or the like, and the base 2 and the heat sink 5 have the same potential.

FIG. 10 shows the semiconductor switching element 1 shown in FIG. 9 with electric symbols for convenience of explanation. When the insulating substrate 3 is viewed vertically as shown, for example, IG
The BT is represented with the collector at the top, the emitter at the bottom, and the gate on the left. FIG. 11 shows a circuit for one phase of the three-level inverter circuit using the display method shown in FIG. Normally, a single-phase or three-phase inverter circuit is formed by connecting a plurality of elements shown in FIG.

Here, semiconductor switching elements 1a, 1b, 1c, 1d such as IGBTs are connected in series to form a switch series circuit, and one end of the switch series circuit forms a positive side DC voltage terminal P. An end forms a DC voltage terminal N on the negative electrode side, and an interconnection point between the semiconductor switching elements 1b and 1c forms an AC voltage terminal AC. Also, two semiconductor switching elements 1a on the positive electrode side
A diode series formed by connecting clamping diodes 6 and 7 in series is connected between an interconnection point of the two semiconductor switching elements 1c and 1d on the negative electrode side. Further, two capacitors 8 and 9 for waveform shaping and voltage division are connected in series, one end of the series connection circuit is connected to the DC voltage terminal P on the positive side, and the other end is connected to the DC voltage terminal N on the negative side. Have been. The interconnection point between the capacitors 8 and 9 and the interconnection point between the diodes 6 and 7 form a neutral point C.

The semiconductor switching elements 1a, 1
Each of b, 1c, and 1d may be a single switching element or a plurality of switching elements connected in series or in parallel. Each of the capacitors 8 and 9 may be a single capacitor or a plurality of capacitors connected in parallel.

On the other hand, the semiconductor switching elements 1a, 1
b, 1c, 1d are individual insulating substrates 3a, 3b,
They are mounted on bases 2a, 2b, 2c, 2d via 3c, 3d, and these are mounted on a single heat sink 5. The DC voltage terminal P on the positive electrode side and the DC voltage terminal N on the negative electrode side are connected to a DC power supply (not shown), and the heat sink 5 is grounded by a connection line 10 or provided in a housing for accommodating a three-level inverter circuit. Or be connected. Further, the semiconductor switching elements 1a, 1
A control signal of a control circuit (not shown) is applied to each of the gates b, 1c, and 1d, whereby the DC voltage terminals P, N
The DC power supplied between them is converted into AC and the AC terminal A
Output from C.

The general structure and operation of the three-level inverter circuit are described in various documents and are publicly known.
Although the base and the insulating substrate on which this is mounted are omitted for the semiconductor device 7, the semiconductor switching devices 1a, 1b, 1c, 1d
In many cases, it is mounted on the heat sink 5 in the same manner as described above.

In the above-described example, the case where an IGBT is used as a semiconductor switching element has been described. Instead, a bipolar transistor, a thyristor, a gate turn-off thyristor, or the like can be used. Can be configured in substantially the same manner as described above.

Further, although the above-described one shows an inverter circuit for converting DC power to AC power, a converter circuit for converting AC power to DC power can also be configured in substantially the same manner as described above.

[0012]

In the inverter circuit shown in FIG. 11, the semiconductor switching elements 1a, 1
b, 1c, 1d and bases 2a, 2 electrically connected
b, 2c, 2d and the heat sink 5 between the insulating substrate 3
a, 3b, 3c, and 3d, only 3
When the circuit voltage of the level inverter circuit, that is, the voltage between the DC voltage terminals PN increases, it is necessary to increase the dielectric strength of the insulating substrates 3a, 3b, 3c, 3d accordingly.

For example, when the circuit voltage of the three-level inverter circuit is 6 kV, the required breakdown voltage of the device is 4 + 1.8 according to JEC (Standards of the Institute of Electrical Engineers of Japan) -2410.
× 6/2 ^1/2 = 11.6 kV, and the insulating substrates 3a, 3b, 3c, 3d having a withstand voltage higher than this voltage are required. Therefore, the physical properties of the insulating substrates 3a, 3b, 3c, 3d are required. Thickness must be increased.

However, the insulating substrates 3a, 3b, 3c, 3
When the thickness d increases, the thermal resistance increases, and the heat generated from the semiconductor switching elements 1a, 1b, 1c, 1d becomes difficult to be transmitted to the heat sink 5, so that the semiconductor switching element 1
The temperatures of a, 1b, 1c, and 1d rise, and the ability cannot be fully exhibited. In addition, the reliability of the device may be reduced due to the temperature rise.

The present invention has been made to solve the above problems, and has as its object to provide a power converter capable of reducing the required withstand voltage for a semiconductor element even at the same circuit voltage.

[0016]

The invention according to claim 1 is
A switch series circuit in which four semiconductor switching elements are connected in series, both ends are DC voltage terminals, and an intermediate connection point is an AC voltage terminal, and two sets of capacitors are connected in series, and an interconnection point is a neutral point. , A capacitor series circuit having both ends connected to both ends of a switch series circuit, two diodes connected in series, an interconnection point connected to a neutral point, and one end connected to two semiconductors at one end of the switch series circuit. A diode series circuit connected to an interconnection point of the switching elements, the other end of which is connected to an interconnection point of two semiconductor switching elements at the other end of the switch series circuit;
In a power converter in which at least one of a semiconductor switching element and a diode is incorporated as an insulating module type power semiconductor element mounted on a conductive substrate via an insulating substrate, the insulating module type power semiconductor element is mounted on a conductive heat sink, A conductive heat sink is connected to a neutral point.

According to a second aspect of the present invention, there is provided a switch series circuit in which four semiconductor switching elements are connected in series, both ends are DC voltage terminals, and an intermediate connection point is an AC voltage terminal, and two sets of capacitors are connected in series. Connected, with the interconnection point as the neutral point, a capacitor series circuit with both ends connected to both ends of the switch series circuit, two diodes connected in series, the interconnection point connected to the neutral point, one end A diode series circuit having one end connected to the interconnection point of the two semiconductor switching elements at one end of the switch series circuit and the other end connected to the interconnection point of the two semiconductor switching elements at the other end of the switch series circuit; Wherein at least one of the semiconductor switching element and the diode is incorporated as an insulated module type power semiconductor element mounted on the conductive substrate via the insulated substrate. In the power conversion device, the insulated module type power semiconductor device is mounted on a conductive heat sink, and the conductive heat sink is connected to one of the positive and negative DC voltage terminals. .

According to a third aspect of the present invention, there is provided a switch series circuit in which four semiconductor switching elements are connected in series, both ends are DC voltage terminals, and an intermediate connection point is an AC voltage terminal, and two sets of capacitors are connected in series. Connected, with the interconnection point as the neutral point, a capacitor series circuit with both ends connected to both ends of the switch series circuit, two diodes connected in series, the interconnection point connected to the neutral point, one end A diode series circuit having one end connected to the interconnection point of the two semiconductor switching elements at one end of the switch series circuit and the other end connected to the interconnection point of the two semiconductor switching elements at the other end of the switch series circuit; Wherein at least one of the semiconductor switching element and the diode is incorporated as an insulated module type power semiconductor element mounted on the conductive substrate via the insulated substrate. In a power converter, an insulating module type power semiconductor device is mounted on a conductive heat sink divided into a positive electrode side and a negative electrode side, and a positive side DC voltage terminal is connected to the positive side heat sink. And a DC voltage terminal on the negative electrode side is connected to the heat sink.

According to a fourth aspect of the present invention, there is provided a switch series circuit in which four semiconductor switching elements are connected in series, both ends are DC voltage terminals, and an intermediate connection point is an AC voltage terminal, and two sets of capacitors are connected in series. Connected, with the interconnection point as the neutral point, a capacitor series circuit with both ends connected to both ends of the switch series circuit, two diodes connected in series, the interconnection point connected to the neutral point, one end A diode series circuit having one end connected to the interconnection point of the two semiconductor switching elements at one end of the switch series circuit and the other end connected to the interconnection point of the two semiconductor switching elements at the other end of the switch series circuit; Wherein at least one of the semiconductor switching element and the diode is incorporated as an insulated module type power semiconductor element mounted on the conductive substrate via the insulated substrate. In that the power conversion device, is characterized in that the insulating module-type power semiconductor device is mounted on a conductive heat sink, and connected to conductive heat sink in the AC voltage terminal.

According to a fifth aspect of the present invention, there is provided a switch series circuit in which four semiconductor switching elements are connected in series, both ends are DC voltage terminals, and an intermediate connection point is an AC voltage terminal, and two sets of capacitors are connected in series. Connected, with the interconnection point as the neutral point, a capacitor series circuit with both ends connected to both ends of the switch series circuit, two diodes connected in series, the interconnection point connected to the neutral point, one end A diode series circuit having one end connected to the interconnection point of the two semiconductor switching elements at one end of the switch series circuit and the other end connected to the interconnection point of the two semiconductor switching elements at the other end of the switch series circuit; Wherein at least one of the semiconductor switching element and the diode is incorporated as an insulated module type power semiconductor element mounted on the conductive substrate via the insulated substrate. In the power conversion device, the insulated module type power semiconductor device is mounted on a mutually separated conductive heat sink, and the heat sink is connected to one end of the insulated module type power semiconductor device mounted thereon. Things.

According to a sixth aspect of the present invention, in the power converter according to any one of the first to fifth aspects, an impedance element is connected to a path connecting another heat sink. is there.

According to a seventh aspect of the present invention, in the power converter according to any one of the first to fifth aspects, a fuse is connected to a path for connecting a heat sink to another. .

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on preferred embodiments shown in the drawings. FIG. 1 is a circuit diagram showing a configuration of a first embodiment of a power conversion device according to the present invention together with a cooling system of a main element. In the drawing, the same elements as those in FIG. The description is omitted here. In the conventional power converter, the heat sink 5 is grounded. However, in the first embodiment shown here, the connection line 11 is used.
The only difference is that the heat sink 5 is connected to the neutral point C with respect to the configuration, and the other configuration is the same as that of the conventional device shown in FIG.

Hereinafter, the operation of the conventional apparatus will be described focusing on parts having a different configuration. First, the insulating substrates 3a, 3
The maximum value of the voltage applied to b, 3c, 3d is determined by the voltage Ep between the positive DC voltage terminal P and the neutral point C, and the voltage between the neutral point C and the negative DC voltage terminal N. Of the voltage En of
One voltage having a larger absolute value is obtained. Ep = En = 3 kV
In this case, the insulating substrates 3a, 3b, 3c, and 3d only need to have a withstand voltage of 3 kV, which is about 1/4 of the required voltage of 11.6 kV based on JEC-2410 as described above. . This means that the required voltage when the diodes 7 and 8 are insulated module-type elements is also about １ ／.

Thus, according to the first embodiment, the required breakdown voltage for the semiconductor element can be reduced even with the same circuit voltage.

FIG. 2 is a circuit diagram showing the configuration of a second embodiment of the power converter according to the present invention, together with the cooling system of the main element. In the figure, the same elements as those in FIG. And the description is omitted. This embodiment has a configuration in which the heat sink 5 is connected to the DC voltage terminal N on the negative electrode side by a connection line 12.

According to this configuration, the insulating substrates 3a, 3b,
The maximum values of the voltages applied to 3c and 3d are the voltage Ep between the positive DC voltage terminal P and the neutral point C, and the voltage between the neutral point C and the negative DC voltage terminal N. Sum voltage with En,
That is, Ep + En is obtained, and when the circuit voltage of the three-level inverter circuit is 6 kV, the required voltage is about ｋ of the required voltage of 11.6 kV based on JEC-2410. This means that the required voltage when the diodes 7 and 8 are insulated module elements is also reduced to about 1/2.

Thus, according to the second embodiment, the required withstand voltage for the semiconductor element can be reduced even with the same circuit voltage.

FIG. 3 is a circuit diagram showing a configuration of a third embodiment of the power converter according to the present invention, together with a cooling system of a main element. In the figure, the same elements as those in FIG. And the description is omitted. In this embodiment, the heat sink 5 shown in FIG. 1 is replaced with a heat sink 5p on which the semiconductor switching elements 1a and 1b on the positive side of the DC voltage are mounted.
And a heat sink 5n on which the semiconductor switching elements 1c and 1d on the negative side of the DC voltage are mounted. The heat sink 5p is connected to the DC voltage terminal P on the positive side by the connection line 13, and the heat sink 5n is connected by the connection line 14. Is connected to the DC voltage terminal N on the negative electrode side.

According to this configuration, the maximum value of the voltage applied to the insulating substrates 3a to 3d is a voltage Ep between the DC voltage terminal P on the positive electrode side and the neutral point C, a voltage Ep between the neutral point C and the negative electrode Sum with the voltage En between the DC voltage terminal N on the side
When the circuit voltage of the three-level inverter circuit is 6 kV, the required voltage is about 約 of the required voltage of 11.6 kV based on JEC-2410.
This means that the required voltage when the diodes 7 and 8 are insulated module elements is also reduced to about 1/2.

Thus, according to the third embodiment, the required withstand voltage for the semiconductor element can be reduced even with the same circuit voltage.

FIG. 4 is a circuit diagram showing the configuration of a fourth embodiment of the power converter according to the present invention, together with the cooling system of the main element, in which the same elements as those in FIG. And the description is omitted. This embodiment has a configuration in which the heat sink 5 is connected to an AC voltage terminal AC by a connection line 15.

According to this configuration, the maximum value of the voltage applied to the insulating substrates 3a to 3d is determined by the voltage Ep between the DC terminal P on the positive electrode side and the neutral point C, the voltage Ep between the neutral point C and the negative electrode Sum with the voltage En between the DC voltage terminal N on the side
When the circuit voltage of the three-level inverter circuit is 6 kV, the required voltage is about 約 of the required voltage of 11.6 kV based on JEC-2410.
This means that the required voltage when the diodes 7 and 8 are insulated module elements is also reduced to about 1/2.

Thus, according to the fourth embodiment, the required withstand voltage for the semiconductor element can be reduced even with the same circuit voltage.

FIG. 5 is a circuit diagram showing the configuration of a fifth embodiment of the power converter according to the present invention, together with the cooling system of the main element, in which the same elements as those in FIG. And the description is omitted. In this embodiment, the heat sink 5 shown in FIG.
Divided into four heat sinks 5a to 5d corresponding to the insulated module type power semiconductor elements including
6, the heat sink 5a is connected to the semiconductor switching element 1
a, for example, to the emitter of an IGBT, similarly connecting the heat sink 5b to the low voltage side of the semiconductor switching element 1b by the connection line 17, and connecting the heat sink 5c to the low voltage side of the semiconductor switching element 1c by the connection line 18. The configuration is such that the heat sink 5d is connected to the low voltage side of the semiconductor switching element 1d by the wire 19, respectively.

According to this configuration, the maximum value of the voltage applied to the insulating substrates 3a to 3d depends on the voltage Ep between the DC voltage terminal P on the positive electrode side and the neutral point C, the voltage Ep between the neutral point C and the negative electrode It is one of the voltages En having the larger absolute value among the voltages En with the DC voltage terminal N on the side. For example, when Ep = En = 3 kV,
The insulating substrates 3a to 3d only need to have a withstand voltage of 3 kV. As described above, the required voltage 1 based on the regulation of JEC-2410
The required voltage is about 1/4 of 1.6 kV. This means that the required voltage when the diodes 7 and 8 are insulated module-type elements is also about １ ／.

Thus, according to the fifth embodiment, the required withstand voltage for the semiconductor element can be greatly reduced even with the same circuit voltage.

In the fifth embodiment shown in FIG.
The heat sinks 5a to 5d are connected to the low voltage side of the corresponding semiconductor switching elements 1a to 1d.
semiconductor switching elements 1a to 1d corresponding to a to 5d
A similar effect can be obtained even if the configuration is such that the connection is made to the high voltage side.

FIG. 6 is a circuit diagram showing the configuration of a sixth embodiment of the power converter according to the present invention, together with the cooling system of the main element, in which the same elements as those in FIG. And the description is omitted. In this embodiment, the heat sink 5 is connected to the neutral point C by a connection line 11 similarly to the first embodiment shown in FIG. 1, but the point that an impedance element 20 is connected to the connection path is different from that of FIG. Is different. Here, the impedance element 20 is configured by one or a combination of two or more of a resistor, a reactor, and a capacitor.

According to this configuration, in addition to the effect of the first embodiment shown in FIG. 1, the level of the neutral point C can be maintained at a constant value, for example, the ground level, and the required voltage is determined. can do.

The heat sink is connected to DC voltage terminals P and N
The same effect as described above can be obtained by connecting an impedance element to the neutral point C or a path connected to one end of the semiconductor switching element.

FIG. 7 is a circuit diagram showing the configuration of a seventh embodiment of the power converter according to the present invention, together with the cooling system of the main element, in which the same elements as those in FIG. And the description is omitted. This embodiment differs from 6 in that a fuse 21 is connected instead of the impedance element 20 shown in FIG.

According to this configuration, in addition to the effect of the first embodiment shown in FIG. 1, the level of the neutral point C can be maintained at a constant value, for example, the ground level, and the required voltage is determined. can do.

The heat sink is connected to DC voltage terminals P and N
The same effect as described above can be obtained by connecting a fuse to the neutral point C or a path connected to one end of the semiconductor switching element.

[0045]

As is apparent from the above description, according to the present invention, it is possible to provide a power converter capable of reducing the required withstand voltage for a semiconductor element even with the same circuit voltage.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a configuration of a first embodiment of a power converter according to the present invention, together with a cooling system of a main element.

FIG. 2 is a circuit diagram showing a configuration of a second embodiment of the power converter according to the present invention, together with a cooling system of a main element.

FIG. 3 is a circuit diagram showing a configuration of a third embodiment of the power converter according to the present invention, together with a cooling system of a main element.

FIG. 4 is a circuit diagram showing a configuration of a fourth embodiment of the power converter according to the present invention, together with a cooling system of a main element.

FIG. 5 is a circuit diagram showing a configuration of a fifth embodiment of the power converter according to the present invention, together with a cooling system of a main element.

FIG. 6 is a circuit diagram showing a configuration of a sixth embodiment of the power converter according to the present invention, together with a cooling system of a main element.

FIG. 7 is a circuit diagram showing a configuration of a seventh embodiment of the power converter according to the present invention, together with a cooling system of a main element.

FIG. 8 is a perspective view showing an example of an internal structure of the insulated module type power conversion element, which is sequentially cut away.

FIG. 9 is a longitudinal sectional view showing a mounting structure of main elements of the insulated module type power conversion element shown in FIG. 8;

FIG. 10 is a schematic diagram showing a semiconductor chip among the main elements shown in FIG. 9 by electric symbols;

FIG. 11 is a circuit diagram showing a configuration of a conventional power converter using the schematic diagram shown in FIG. 10;

[Explanation of symbols]

 1, 1a, 1b, 1c, 1d Semiconductor switching element 2, 2a, 2b, 2c, 2d Base 3, 3a, 3b, 3c, 3d Insulating substrate 4 Case 5, 5a, 5b, 5c, 5d Heat sink 6, 7 Diode 8 , 9 Capacitors 10-19 Connection line 20 Impedance element 21 Fuse P, N DC voltage terminal C Neutral point AC AC voltage terminal

Claims (7)

[Claims] 1. A switch series circuit in which four semiconductor switching elements are connected in series, both ends of which are DC voltage terminals, and an intermediate connection point is an AC voltage terminal, and two sets of capacitors are connected in series, and are interconnected. Is a neutral point, a capacitor series circuit having both ends connected to both ends of the switch series circuit, two diodes are connected in series, an interconnection point is connected to the neutral point, and one end is the switch series circuit. Is connected to the interconnection point of the two semiconductor switching elements at one end, and the other end is connected to the other end of the switch series circuit.
A diode series circuit connected to an interconnection point of the semiconductor switching elements, wherein at least one of the semiconductor switching elements and the diode is an insulating module type power semiconductor element mounted on a conductive substrate via an insulating substrate. A power conversion device to be incorporated, wherein the insulating module-type power semiconductor element is mounted on a conductive heat sink, and the conductive heat sink is connected to the neutral point. 2. A switch series circuit in which four semiconductor switching elements are connected in series, both ends of which are DC voltage terminals, and an intermediate connection point is an AC voltage terminal, and two sets of capacitors are connected in series, and are interconnected. Is a neutral point, a capacitor series circuit having both ends connected to both ends of the switch series circuit, two diodes are connected in series, an interconnection point is connected to the neutral point, and one end is the switch series circuit. Is connected to the interconnection point of the two semiconductor switching elements at one end, and the other end is connected to the other end of the switch series circuit.
A diode series circuit connected to an interconnection point of the semiconductor switching elements, wherein at least one of the semiconductor switching elements and the diode is an insulating module type power semiconductor element mounted on a conductive substrate via an insulating substrate. In the power conversion device to be incorporated, the insulating module type power semiconductor element is mounted on a conductive heat sink, and the conductive heat sink is connected to any one of a DC voltage terminal on a positive electrode side and a negative electrode side. Power converter. 3. A switch series circuit in which four semiconductor switching elements are connected in series, both ends of which are DC voltage terminals, and an intermediate connection point is an AC voltage terminal; Is a neutral point, a capacitor series circuit having both ends connected to both ends of the switch series circuit, two diodes are connected in series, an interconnection point is connected to the neutral point, and one end is the switch series circuit. Is connected to the interconnection point of the two semiconductor switching elements at one end, and the other end is connected to the other end of the switch series circuit.
A diode series circuit connected to an interconnection point of the semiconductor switching elements, wherein at least one of the semiconductor switching elements and the diode is an insulating module type power semiconductor element mounted on a conductive substrate via an insulating substrate. In the built-in power converter, the insulating module type power semiconductor element is mounted on a conductive heat sink divided into a positive electrode side and a negative electrode side, and the positive electrode side heat sink is connected to the positive electrode side DC voltage terminal. A power converter wherein the DC voltage terminal on the negative electrode side is connected to the heat sink on the negative electrode side. 4. A switch series circuit in which four semiconductor switching elements are connected in series, both ends of which are DC voltage terminals, and an intermediate connection point is an AC voltage terminal, and two sets of capacitors are connected in series, and are interconnected. Is a neutral point, a capacitor series circuit having both ends connected to both ends of the switch series circuit, two diodes are connected in series, an interconnection point is connected to the neutral point, and one end is the switch series circuit. Is connected to the interconnection point of the two semiconductor switching elements at one end, and the other end is connected to the other end of the switch series circuit.
A diode series circuit connected to an interconnection point of the semiconductor switching elements, wherein at least one of the semiconductor switching elements and the diode is an insulating module type power semiconductor element mounted on a conductive substrate via an insulating substrate. A power converter, wherein the insulating module-type power semiconductor element is mounted on a conductive heat sink, and the conductive heat sink is connected to the AC voltage terminal. 5. A switch series circuit in which four semiconductor switching elements are connected in series, both ends of which are DC voltage terminals, and an intermediate connection point is an AC voltage terminal; A neutral point, a capacitor series circuit having both ends connected to both ends of the switch series circuit, two diodes connected in series, an interconnection point connected to the neutral point, and one end connected to the switch series circuit. Is connected to the interconnection point of the two semiconductor switching elements at one end, and the other end is connected to the other end of the switch series circuit.
A diode series circuit connected to an interconnection point of the semiconductor switching elements, wherein at least one of the semiconductor switching elements and the diode is an insulating module type power semiconductor element mounted on a conductive substrate via an insulating substrate. In the incorporated power converter, the insulating module-type power semiconductor element is mounted on a mutually separated conductive heat sink, and the heat sink is connected to one end of the insulating module-type power semiconductor element mounted on the heat sink. A power converter characterized by the above-mentioned. 6. A path for connecting the heat sink to another,
The power converter according to any one of claims 1 to 5, wherein an impedance element is connected. 7. A path for connecting the heat sink to another,
The power converter according to any one of claims 1 to 5, wherein a fuse is connected.