JP3213671B2 - Power converter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power converter such as an inverter using a self-extinguishing type semiconductor device.
In particular, the present invention relates to a method for arranging and connecting components of a snubber circuit which is a protection circuit for a self-extinguishing semiconductor device, and more particularly to a structure of a snubber circuit for reducing inductance in the snubber circuit.

[0002]

2. Description of the Related Art FIG. 29 relates to a conventional power converter disclosed in, for example, Japanese Patent Application Laid-Open No. 4-229078, particularly to a method of arranging and connecting a snubber circuit of a self-extinguishing semiconductor device. In the conventional example, reference numeral 1 denotes a GTO (Gate Turn-off) thyristor (hereinafter referred to as G) as an example of a self-extinguishing semiconductor device.
2 is a snubber diode, 3 is a snubber capacitor, and a snubber circuit composed of a series body of the snubber diode 2 and the snubber capacitor 3 constitutes a bypass circuit of the self-extinguishing type semiconductor element 1. 4 is a capacitor hood which is one end of the electrode of the snubber capacitor 3, 5 is the other end of the electrode of the snubber capacitor 3, 6 is a connection between the anode of the snubber diode 2 and the electrode 4 of the snubber capacitor 3, 7 is G
The connection between TO1 and the electrode 5 of the snubber capacitor, 8 is G
Cooling fins 9 of TO1 and cooling fins 9 of GTO1 and snubber diode 2 are provided. This publication discloses that the reduction of parasitic inductance existing in a snubber circuit (not shown) is described in GT.
This is achieved by configuring one terminal 4 of the snubber capacitor 3 constituting the snubber circuit connected to O1 as a well-conductive capacitor hood that partially surrounds the capacitor 3, and this means is provided by the electrical connection of the snubber circuit. It is described as being based on the idea of keeping the line loop length as small as possible. Also, the target GTO 1 has a turn-off current of 2 kA and a rated voltage of about 4.5 kV. The diameter of a current GTO silicon wafer having such an electrical rating is about 4 inches. The capacitance of the snubber capacitor 3 is
It is described as 2.5uF. Further, as a specific snubber diode 2 of the conventional example, a stud type diode having a low rated current and a relatively large parasitic inductance is used. The snubber diode 2 is fixedly connected to the cooling fin 9.

[0003]

Since the conventional power converter is constructed as described above, for example, a self-extinguishing type semiconductor device manufactured using a silicon wafer having a diameter of 6 inches or more, which is currently under development, is used. For example, when GTO is applied, its electrical rating is 6 kV, 6 kA or more. Therefore, the insulation level is completely different from the insulation level of a conventional silicon wafer for GTO having a diameter of about 4 inches, and the necessary insulation distance is inevitably long. In addition, since the current value at which the self-extinguishing type semiconductor element is turned off and cut off increases, and the current value bypassed to the snubber circuit increases, a snubber capacitor having a large rated current and a large capacitance (for example, a turn-off current) Is about 6 uF if the current is 6 kA), and a snubber diode is required, and the distance between the terminals to be connected is inevitably increased. Therefore, the electric line loop length of the snubber circuit is inevitably increased, and the basic idea of the conventional example that the electric line loop length is kept as small as possible even if the conventional connection method of the snubber circuit is applied as it is. It will not be easy to comply. Also, although not mentioned in the conventional example, when the switching frequency of the GTO is increased to improve the control performance of the self-extinguishing semiconductor device, for example, the power converter, the effective current value flowing into the snubber circuit increases, The size of the snubber capacitor and the snubber diode increases, and it becomes more difficult to comply with the above-described basic idea.

When the parasitic inductance existing in the snubber circuit increases, the turn-off loss of the self-extinguishing type semiconductor device at the time of current interruption increases. This will be described with reference to FIG. FIG. 30 shows typical waveforms of the anode-cathode voltage V _AK and the anode-cathode current I _AK when the current of the self-extinguishing semiconductor device is cut off. When the current of the self-extinguishing semiconductor device falls off from the cutoff current, the surplus current is bypassed to the snubber circuit. This bypassed current I _SN generates a charging voltage V _CS for the snubber capacitor. In addition, since the bypass current I _SN has the same current change rate as the absolute value of the current change rate di / dt of the illustrated breakdown current I _AK , the voltage V determined by the product of the current change rate and the parasitic inductance. _LS
Occurs in the snubber circuit. Also, the transient voltage V _DS generated in the snubber diode increases with an increase in the absolute value of the current change rate di / dt. Therefore, the voltage applied to the self-extinguishing semiconductor element is the charging voltage V of the snubber capacitor.
The sum of _CS , the induced voltage V _{LS of the} parasitic inductance, and the transient voltage V _DS of the snubber diode generates a spike-like voltage V _DSP shown at time T1 in the figure. The voltage caused by the rate of change di / dt of the current I _SN bypassed to the snubber circuit is not generated when the self-extinguishing type semiconductor device completes the turn-off operation after T1. charging voltage V _CS of voltage V _AK is the snubber capacitor according to
Only. On the other hand, the energy stored in the parasitic inductance generates an excessive charging voltage of the snubber capacitor, and is one of the factors that increase the maximum value _{VDM of the} voltage applied to the self-extinguishing semiconductor device at time T2.
The loss of the self-extinguishing type semiconductor element in the turn-off operation is based on the current I _AK and the voltage V
_Since it is approximately obtained by the product of _AK , the parasitic inductance present in the snubber circuit is a factor that increases the loss. This loss not only causes a reduction in the efficiency of the power converter, but also, depending on the degree of the loss, breaks the equilibrium state with the cooling capacity of the self-extinguishing type semiconductor element, and causes element destruction due to temperature rise. It becomes a factor.

As described above, the increase in the parasitic inductance existing in the snubber circuit does not function as a protection circuit for the self-extinguishing type semiconductor element, which is a basic function of the snubber circuit, but also lowers the reliability of the power converter. Alternatively, a self-extinguishing type semiconductor device must be used with a reduced turn-off current, which causes a problem such as a reduction in device utilization.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has been made in the case where the electric rating of the self-extinguishing type semiconductor element is large and the components of the snubber circuit which is the protection circuit are enlarged. However, it is an object of the present invention to obtain a power converter that can reduce parasitic inductance existing in a snubber circuit.

[0007]

A power converter according to the present invention comprises a self-extinguishing type semiconductor device and the self-extinguishing type semiconductor device.
Connected to the bypass circuit of the body element,
A snubber circuit consisting of a series body of snubber capacitors and one end
Is the self-extinguishing type semiconductor device and the other end is the snubber diode.
A first wide conductor connected to the circuit, one end of which is self-extinguishing
The other end of the die is connected to the snubber capacitor
A second wide conductor, one end of which is connected to the snubber diode.
Third wide conductor having the other end connected to the snubber capacitor
And a plurality of strip-like wide conductor having a body, said self-turn
The center of the arc-shaped semiconductor element and the center of the snubber diode
The connected line segment, the center of the snubber diode and the snubber
The line connecting the center of the capacitor electrode and the snubber
The center of the capacitor electrode and the self-extinguishing semiconductor device
The self-extinguishing function so that the line connecting the centers is included in the same plane
Arc-shaped semiconductor device, said snubber diode and said snubber
The bus capacitor arranged, all the wide conductor in which arranged in a parallel positional relationship.

[0008] The width of the wide conductor is determined by
May be configured such that the width or more of the most small <br/> have one of the connected at least two electrode surfaces of the width.

In addition, two of the wide conductors are arranged close to each other , and a current flows through these wide conductors in opposite directions.
It may be made to be .

Also, two electrodes of the snubber capacitor
The wide conductors connected to each other are paired in parallel close to each other,
A dielectric may be inserted between the pair of wide conductors.

Further , the self-extinguishing type semiconductor elements are connected in series.
Or a plurality may be connected in series / parallel.

[0012] Further, the power conversion device is a three-level invar.
Data.

[0013]

[0014]

[0015]

[0016]

The power converter according to the present invention can reduce the inductance of the snubber circuit, and can reduce the loss when the self-extinguishing type semiconductor element is cut off.

Also, two electrodes of the snubber capacitor
The wide conductors connected to each other are paired in parallel close to each other,
By inserting a dielectric between the pair of wide conductors,
It is possible to equivalently increase the capacity of the snubber capacitor and reduce the loss when the self-extinguishing type semiconductor element is cut off.

Further , the self-extinguishing type semiconductor elements are connected in series.
Alternatively, by connecting a plurality of power supply devices in series and parallel, the inductance of the snubber circuit in a high-voltage or high-power power converter can be reduced, and the loss when the self-extinguishing semiconductor device is cut off can be reduced.

The power converter is a three-level inverter.
Then, in the three-level inverter, the inductance of the snubber circuit can be reduced, and the loss when the self-extinguishing type semiconductor element is cut off can be reduced.

[0020]

[0021]

[Embodiment 1] A first embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a side view of the structure of a snubber circuit of a self-extinguishing semiconductor device. Here, as an example of the self-extinguishing semiconductor device 1, G
A TO thyristor (hereinafter GTO) will be taken up, but if the electrode surface is flat, a reverse conducting GTO thyristor, IGB
It is also applicable to T, SI thyristor, SIC, and the like. In FIG. 1, additional components used for a freewheel diode, a snubber resistor, a snubber energy regenerating circuit and the like are omitted, but it goes without saying that the present invention can be applied to the basic structure shown here. Further, the insulator, the press-contact structure, and the like are omitted. 1 is a GTO, 2 is a flat snubber diode, not a stud type, 3 is a snubber capacitor, 10 is a cooling fin (may be a conductor) pressed against the anode of GTO1, and 11 is a cooling fin pressed against the cathode of GTO1 ( Conductors); 12, 13 are electrodes of the snubber capacitor 3; 14 is a strip-shaped wide conductor connecting the cooling fin 10 (extension of the anode of the GTO 1) to the anode of the snubber diode 2;
Is a wide conductor connecting the cathode of the snubber diode 2 and the electrode 12 of the snubber capacitor 3, and 16 is a wide conductor connecting the electrode 13 of the snubber capacitor 3 and the cooling fin 11 (an extension of the cathode of the GTO 1). The cooling of the snubber diode 2 may be realized by integrating the cooling fins 10 and the wide conductors 14, or individual cooling means such as cooling fins may be added.

[0022] First described "parallel positional relation between the electrode surface". As shown in FIG. 1 which is a side view of the snubber circuit structure, all six electrode surfaces do not have an angle, that is, the anode surface or the cathode surface of the snubber diode 2 with respect to the anode surface or the cathode surface of the GTO 1. Electrode of snubber capacitor 3
The extended planes of the electrode surfaces 12 and 13 do not intersect in space. Such a positional relationship is referred to as “parallel positional relationship of the electrode surfaces”. As a result, the assembling technique can be simplified at each stage as compared with the conventional example, and the assembling work can be simplified. In particular, since the wide conductors 14, 15, 16 do not require processing such as U-shaped bending, the conductor structure cost can be reduced. Further, this configuration enables a parallel positional relationship of the wide conductors described later, and enables a reduction in line inductance.

Next the "positional relationship of the electrode surface straight line" it will be described. FIG. 2 shows a plan view of the snubber circuit structure. For convenience of explanation, FIG. 2 separately describes the connection between the GTO 1 and the snubber diode 2, the connection between the snubber diode 2 and the snubber capacitor 3, and the connection between the snubber capacitor 3 and the GTO 1; It can be assembled. As shown in FIG. 2, as a precondition, as viewed from the top view, a center line AB connecting a center A of the GTO 1 and a center B of the snubber diode with a straight line, a center B of the snubber diode 2 and an electrode 12 of the snubber capacitor 3 are shown. A center line BC connecting the center C of the snubber capacitor 3 with a straight line and a center line DA connecting the center D of the electrode 13 of the snubber capacitor 3 and the center A of the GTO 1 are in a straight line. Is referred to as a “linear positional relationship between the electrode surfaces”. The electrodes 12 and 13 of the snubber capacitor 3 are usually an aggregate of several terminals (here, the number of terminals is 3) when viewed in a plan view, as shown in FIG. As shown in FIG. 3, the center of the electrodes 12 and 13 of the snubber capacitor 3 means the center of a group of terminals. This configuration ensures that the wide conductors overlap in a plan view, and enables reduction of the line inductance described later.

Next the "parallel positional relationship of the wide conductor" it will be described. In FIG. 1, which is a side view of the snubber circuit structure, the wide conductors 14, 15, and 16 have no angle, that is, the wide conductor 1
The extension planes of 4, 15, and 16 do not intersect in space.
Such a positional relationship is referred to as a “parallel positional relationship between wide conductors”. This configuration makes it possible to reduce the line inductance described later.

[0025] Next will be described the provision of the wide conductor. Specifically, it will be described that the conductor connecting the at least two electrode terminals is a wide conductor that is equal to or larger than the width of the terminal smaller than the width of the at least two terminals to be connected. GTO1 anode (cathode), snubber diode 2
(Anode) and the electrodes 12, 13 of the snubber capacitor 3 all have the same width. Therefore, as shown in FIG. 2, which is a top view of the snubber circuit structure,
For example, the description will be made on the assumption that the width of the electrodes is larger in the order of GTO1, snubber capacitor 3, and snubber diode 2. As the wide conductor 14 connecting the cooling fin 10 of the GTO 1 and the anode of the snubber diode 2, a wide conductor at least equal to the electrode width of the snubber diode 2 is applied, and the cathode of the snubber diode 2 and the electrode 12 of the snubber capacitor 3 are connected. For the wide conductor 15, a wide conductor 15 having at least the electrode width of the snubber diode 2 is applied, and for the wide conductor 16 connecting the electrode 13 of the snubber capacitor 3 and the cooling fin 11 of the GTO 1, at least the snubber capacitor 3 is used.
A wide conductor 16 larger than the width of the electrode 13 is applied. The wide conductors 14, 15, and 16 shown in FIG. 2 are specific examples satisfying the above-described definition of the width of the wide conductor, and the minimum condition of the conductor width will be referred to as "the definition of the width of the wide conductor". This configuration realizes a uniform distribution of the high-frequency current and enables a reduction in the line inductance described later.

Furthermore described provisions of mutual coupling between the wide conductor. More specifically, mutual inductance is provided between the wide conductor 15 connecting the cathode of the snubber diode 2 and the electrode 12 of the snubber capacitor 3 and the wide conductor 16 connecting the electrode 13 of the snubber capacitor 3 and the cathode of the GTO 1. This will be described. First, referring to the “Electrical Engineering Handbook”, the mutual inductance M between two closed circuits is obtained by the Neumann formula (1).

[0027]

(Equation 1)

From this, if the two current values are equal, the mutual inductance M is inversely proportional to the distance r between the lines, and is proportional to the cosine of the angle θ formed by the current vector. Assuming that the self-inductance of each line is L _S , the line inductance L can be obtained by equation (2).

[0029]

(Equation 2)

Since this value does not become negative, in order to make the value as small as possible, the mutual inductance M needs to be as large as possible with a negative sign and approach the value of L _S. In other words, the directions of the currents flowing in the two lines are exactly opposite to each other, that is, 180 ° (accordingly, cos θ = −1) in terms of the angle θ, and the distance r between the lines is set as small as possible.
The arrangement of conductors that satisfies this condition will be referred to as "the definition of mutual coupling between wide conductors". With this configuration, the line inductance can be reduced.

[0031] Next Fig. 1 will be described with reference to the specific example of FIG. In FIG. 1, the wide conductor 14 and the wide conductor 16 and the wide conductor 15 and the wide conductor 16 are in the relationship of the two lines described above. First, regarding the current flowing through the wide conductors 14, 15, and 16, GT
When O1 interrupts the current, the interrupted current is bypassed to the circuit of FIG. 1, and it is clear from Kirchhoff's law that the absolute value of the current is the same for all wide conductors. The angle θ between the current vectors of the wide conductors 14 and 15 and the current vector of the wide conductor 16 is 180 ° as can be seen from FIG. Further, when the GTO 1 interrupts the current, the current flowing through the wide conductors 14, 15, 16 is a high-frequency current, and therefore naturally has a skin effect and the current flows uniformly through each wide conductor. This allows wide conductors
Regarding 14 and 16, the magnetic flux generated from the wide conductor 14 and the magnetic flux generated from the wide conductor 16 effectively cancel each other out,
This leads to an increase in the absolute value of the mutual inductance M and a reduction in the line inductance L. In order to prove the effect of reducing the line inductance L, FIG. 5 shows a three-dimensional analysis result of the line inductance and the actual resistance when the intermediate recess width X for the simple model shape shown in FIG. 4 is used as a parameter. This result indicates that the inductance decreases as X increases, and that the line inductance L can be reduced by reducing the inter-line distance r described above.

[0032] Thus, when the summary of the above matters, GTO1
The electrode surface of the snubber diode 2, the electrode surface of the snubber diode 2, and the "parallel positional relationship with respect to the electrode surface" of the snubber capacitor 3 make it possible to use a wide conductor with a small bending process for the connection means of each electrode surface. This is a condition that the inductance can be reduced and the inductance in the snubber circuit is reduced. GTO1 electrode surface, snubber diode 2
The “position of a straight line with respect to the electrode surface” of the electrode surface of the snubber capacitor 3 is such that the current directions of the wide conductor are 0 ° and 180 °.
This is a condition that the mutual inductance between the wide conductors can be increased and the inductance in the snubber circuit can be reduced. Regarding the "parallel positional relationship of the wide conductor" and "the definition of the width of the wide conductor", in particular, of the two electrodes to be connected, the application of a wide conductor whose width is equal to or greater than the smaller width of the electrode is applied to the wide conductor surface. This is a condition that allows a high-frequency current to flow uniformly and reduces the inductance in the snubber circuit. Furthermore, the `` regulation of mutual coupling between wide conductors '' that makes the distance between wide conductors in which the direction of current is opposite in order to make the mutual coupling denser and increase the absolute value of the mutual inductance is called This is a condition that can be reduced. In addition, by connecting the snubber circuit realized in compliance with these basic conditions to the bypass circuit of the self-extinguishing semiconductor device, the spike-like voltage V _DSP shown in FIG. 30 can be reduced, and the turn-off loss can be reduced. become. Further, the above configuration is a self-extinguishing type semiconductor element,
In this configuration, the area of the circuit formed by the snubber diode, the snubber capacitor, and the wide conductor in the side view is reduced as compared with the total cross-sectional area. If the other conditions are the same, the inductance of the circuit has a property that it is almost proportional to the area surrounding the circuit, and thus the above configuration enables the inductance to be reduced.

Embodiment 2 FIG . A second embodiment of the present invention will be described with reference to the drawings. FIG.
Shows the structure of the snubber circuit of the self-extinguishing type semiconductor device in another combination based on the design concept of the first embodiment. 1 is G
TO, 2 is a snubber diode, 3 is a snubber capacitor,
10 is a cooling fin (or a conductor) pressed against the anode of the GTO 1, 11 is a cooling fin (or a conductor) pressed against the cathode of the GTO 1, 12 and 13 are electrodes of the snubber capacitor 3, and 14 is a cooling fin 11 ( A wide conductor for connecting the cathode of the GTO 1) to the cathode of the snubber diode 2, a wide conductor 15 for connecting the anode of the snubber diode 2 and the electrode 12 of the snubber capacitor 3, and a reference numeral 16 for the electrode 13 of the snubber capacitor 3.
And the cooling fins 10 (extensions of the anode of the GTO 1). The cooling of the snubber diode 2 may be realized by integrating the cooling fins 11 and the wide conductors 14, or cooling means such as individual cooling fins may be added.

FIG . 6 differs from FIG. 1 in that GTO1
Is the connection order of the snubber diode 2 and the snubber capacitor 3 connected in parallel to each other. Specifically, in FIG.
1, the snubber diode 2 and the snubber capacitor 3 are connected in this order from the anode side of the GTO 1, but in FIG. 6, the snubber capacitor 3 and the snubber diode 2 are connected in parallel from the anode side of the GTO 1 in parallel with the GTO 1. Connected.
FIG. 6 is a side view of the snubber circuit structure, in which all electrode surfaces are arranged in a parallel positional relationship, and all wide conductors are in a parallel positional relationship. Also, as shown in the plan view of FIG.
All electrode surfaces are arranged in a linear positional relationship. Further, the definition of the width of the wide conductor and the mutual coupling relationship between the wide conductors are the same as those in FIG. That is, the snubber circuit structure of FIG.
It is clear that the effect of reducing the inductance in the snubber circuit shown by the above is the same.

Embodiment 3 FIG . A third embodiment of the present invention will be described with reference to the drawings. FIG.
Shows the structure of the snubber circuit of the self-extinguishing type semiconductor device in another combination based on the design concept of the first embodiment. 1 is G
TO, 2 is a snubber diode, 3 is a snubber capacitor,
10 is a cooling fin (may be a conductor) pressed against the anode of GTO1, 11 is a cooling fin (may be a conductor) pressed against the cathode of GTO1, 12, 13 are the electrodes of the snubber capacitor 3, and 14 is the cooling fin 10. A wide conductor connecting the anode of the snubber diode 2, a wide conductor 15 connecting the cathode of the snubber diode 2 and the electrode 12 of the snubber capacitor 3, and a wide conductor 16 connecting the electrode 13 of the snubber capacitor 3 and the cooling fin 11 It is.

FIG . 8 differs from FIG. 1 in that GTO1
In FIG. 1, the snubber diode 2 and the snubber capacitor 3 are disposed closer to the GTO 1, but in FIG. 8, the snubber diode 2 and the snubber capacitor 3 are disposed closer to the GTO 1. Thus, the snubber capacitor 3 is arranged closer to the snubber diode 2. Although the side view of the snubber circuit structure with respect to FIG. 8 is omitted, it is clear that the snubber circuit structure of FIG. 8 applies the method of reducing the snubber circuit inductance shown in FIG. Reduction is possible.

Embodiment 4 FIG . A fourth embodiment of the present invention will be described with reference to the drawings. FIG.
Shows the structure of the snubber circuit of the self-extinguishing type semiconductor device in another combination based on the design concept of the first embodiment. 1 is G
TO, 2 is a snubber diode, 3 is a snubber capacitor,
10 is a cooling fin (may be a conductor) pressed against the anode of GTO1, 11 is a cooling fin (may be a conductor) pressed against the cathode of GTO1, 12, 13 are electrodes of the snubber capacitor 3, and 14 is a cooling fin 11. A wide conductor that connects the cathode of the snubber diode 2, 15 is a wide conductor that connects the anode of the snubber diode 2 and the electrode 12 of the snubber capacitor 3, and 16 is a wide conductor that connects the electrode 13 of the snubber capacitor 3 and the cooling fin 10. Conductor.

FIG . 9 differs from FIG. 6 in that GTO1
In FIG. 6, the snubber diode 2 is arranged closer to the GTO 1 than the snubber capacitor 3, but in FIG. 9, the snubber diode 2 and the snubber capacitor 3 are arranged closer to the GTO 1 in FIG. Thus, the snubber capacitor 3 is arranged closer to the snubber diode 2. Although the side view of the snubber circuit structure with respect to FIG. 9 is omitted, it is clear that the snubber circuit structure of FIG. 9 applies the method of reducing the snubber circuit inductance shown in FIG. Reduction is possible.

Embodiment 5 FIG . A fifth embodiment of the present invention will be described with reference to the drawings. FIG.
9 shows the structure of a snubber circuit of a self-extinguishing semiconductor device implemented by partially modifying the design concept of the first embodiment. 1 is GT
O, 2 is a snubber diode, 3 is a snubber capacitor, 10
Are cooling fins (which may be conductors) pressed against the anode of GTO1, 11 are cooling fins (which may be conductors) which are pressed against the cathode of GTO1, 12, 13 are electrodes of the snubber capacitor 3, 14
Is a wide conductor connecting the cooling fin 10 and the anode of the snubber diode 2, 15 is a wide conductor connecting the cathode of the snubber diode 2 and the electrode 12 of the snubber capacitor 3, and 16 is an electrode 13 of the snubber capacitor 3 and the cooling fin 11 And a wide conductor for connecting

FIG . 10 differs from FIG. 1 in that the GTO
1. The point is that the electrode surfaces of the electrodes 12 and 13 of the snubber capacitor 3 are not arranged in a parallel positional relationship with the electrode surface of the snubber diode 2. Specifically, in FIG. 1, all the electrodes 12 and 13 of the snubber capacitor 3 are arranged in a parallel positional relationship by making the heights of the electrodes 12 and 13 different, but in FIG. 10, the electrodes 12 and 13 of the same height are arranged. Apply snubber capacitor 3 with 13,
Further, L-shaped wide conductors 15 and 16 are applied. Thus, the advantage of FIG. 10 compared to FIG. 1 is that the self-inductance of the wide conductor 15 is reduced, and thus the inductance in the snubber circuit can be reduced. This is a wide conductor
The non-parallel parts 15 and 16 move toward the wide conductor 16 in FIG.
This is due to the fact that there are more than the wide conductors 16 in FIG. Although the side view of the snubber circuit structure shown in FIG. 10 is omitted, it is clear that the snubber circuit structure shown in FIG. 10 can be equal to or more than the effect of reducing the inductance in the snubber circuit shown in FIG.

Embodiment 6 FIG . A sixth embodiment of the present invention will be described with reference to the drawings. FIG.
9 shows the structure of a snubber circuit of a self-extinguishing semiconductor device implemented by partially modifying the design concept of the first embodiment. 1 is GT
O, 2 is a snubber diode, 3 is a snubber capacitor, 10
Are cooling fins (which may be conductors) pressed against the anode of GTO1, 11 are cooling fins (which may be conductors) which are pressed against the cathode of GTO1, 12, 13 are electrodes of the snubber capacitor 3, 14
Is a wide conductor connecting the cooling fin 11 and the cathode of the snubber diode 2, 15 is a wide conductor connecting the anode of the snubber diode 2 and the electrode 12 of the snubber capacitor 3, and 16 is an electrode 13 of the snubber capacitor 3 and the cooling fin 10. And a wide conductor for connecting

FIG . 11 differs from FIG. 6 in that the GTO
1. The point is that the electrode surfaces of the electrodes 12 and 13 of the snubber capacitor 3 are not arranged in a parallel positional relationship with the electrode surface of the snubber diode 2. Specifically, in FIG. 6, all the electrodes 12 and 13 of the snubber capacitor 3 are arranged in a parallel positional relationship by making the heights of the electrodes 12 and 13 different, but in FIG. 11, the electrodes 12 and 13 of the same height are arranged. Apply snubber capacitor 3 with 13,
Further, L-shaped wide conductors 15 and 16 are applied. The advantage of FIG. 11 in comparison with FIG. 6 is that the self-inductance of the wide conductor 16 is reduced, and thus the inductance in the snubber circuit can be reduced. This is a wide conductor
The non-parallel parts of 15 and 16 move toward the wide conductor 16 in FIG.
This is due to the fact that there are more than the wide conductors 16 in FIG. Although a side view of the snubber circuit structure with respect to FIG. 11 is omitted, it is clear that the snubber circuit structure of FIG. 11 can be equal to or more than the effect of reducing the inductance in the snubber circuit shown in FIG.

Reference Example 1 FIG. 1 is a diagram showing a structure of a snubber circuit of a self-extinguishing semiconductor device. 1 is a GTO, 2 is a snubber diode, 3 is a snubber capacitor, 10 is a cooling fin (or a conductor) pressed against the anode of GTO1, 11 is a cooling fin (or a conductor) pressed against the cathode of GTO1, 12, 13 is an electrode of the snubber capacitor 3, 14 is a wide conductor connecting the cooling fin 10 and the anode of the snubber diode 2, 15 is a wide conductor connecting the cathode of the snubber diode 2 and the electrode 12 of the snubber capacitor 3, and 16 is a snubber. This is a wide conductor connecting the electrode 13 of the capacitor 3 and the cooling fin 11.

FIG . 12 differs from FIG. 2 in that the electrode surfaces of the snubber diode 2 and the snubber capacitor 3
The point is that the electrode surfaces of TO1 are not arranged in a linear positional relationship. Specifically, in FIG. 2, a straight line AB, a straight line BC,
Although the straight line DA is located on a straight line, in FIG.
The straight line AD is not located on the straight line of the straight line BC. But Figure 12
If the side view of the snubber circuit structure is the same as that of FIG. 1, all electrode surfaces are in a parallel positional relationship, and all wide conductors are in a parallel positional relationship. Further, as shown in FIG. 12, the width of the wide conductor is satisfied. It is clear that the snubber circuit structure of FIG. 12 can be made substantially equivalent to the effect of reducing the inductance in the snubber circuit shown in FIG. 2 except that all the electrode surfaces are not on a straight line.

Embodiment 7 FIG. FIG. 13 shows the structure of a snubber circuit of a self-extinguishing semiconductor device implemented by partially modifying the design concept of the first embodiment. 1 is G
TO, 2 is a snubber diode, 3 is a snubber capacitor,
10 is a cooling fin (may be a conductor) pressed against the anode of GTO1, 11 is a cooling fin (may be a conductor) pressed against the cathode of GTO1, 12, 13 are the electrodes of the snubber capacitor 3, and 14 is the cooling fin 10. A wide conductor that connects the anode of the snubber diode 2, 15 is a wide conductor that connects the cathode of the snubber diode 2 and the electrode 12 of the snubber capacitor 3, and 16 is a wide conductor that connects the electrode 13 of the snubber capacitor 3 and the cooling fin 11. Conductor.

FIG . 13 differs from FIG. 2 in that the electrode surfaces of snubber diode 2 and snubber capacitor 3
The point is that the electrode surfaces of TO1 are not arranged in a linear positional relationship. Specifically, in FIG. 2, a straight line AB, a straight line BC,
Although the straight line DA is located on a straight line, in FIG.
The straight line AD is not located on the straight line of the straight line BC. But Figure 13
If the side view of the snubber circuit structure is the same as that of FIG. 1, all electrode surfaces are in a parallel positional relationship, and all wide conductors are in a parallel positional relationship. As shown in FIG. 13, the definition of the width of the wide conductor is also satisfied. Another advantage of the width of the wide conductor as compared with FIG.
Tangent line P1 between the electrode of O1 and the electrode of snubber diode 2,
P2 is inside the wide conductor 14, and tangent lines Q1, Q2 between the electrode of the snubber diode 2 and the electrode 12 of the snubber capacitor 3
Are inside the wide conductor 15, and tangent lines R1 and R2 between the electrode 13 of the snubber capacitor 3 and the electrode of the GTO1 are wide conductors.
Since it is located inside the block 16, the electric field concentration due to the high-frequency current bypassed by the snubber circuit when the GTO 1 is cut off can be avoided. In FIG. 12, electric field concentration may occur particularly at the connection between the cooling fin 10 and the wide conductor 14. When the electric field concentration occurs, heat loss occurs locally, which causes an increase in the junction temperature of the GTO 1 and eventually causes element destruction. Therefore, the snubber circuit structure shown in FIG. 13 can be made almost equivalent to the effect of reducing the inductance in the snubber circuit shown in FIG. 2 except that all the electrodes are not on a straight line, and the temperature in the wide conductor can be reduced. It is clear that the rise can be equalized.

A wide conductor for avoiding the electric field concentration
That the concept of width can be applied to other examples
Needless to say. Further, in FIG. 13, wide conductors 14, 15, 16 are shown.
When viewed from the top, a rectangular one was applied, but for example,
For conductor 14, the width of the shape cut along tangent P1
Reduce the cost of wide conductors by applying wide conductors 14, etc.
It is also possible.

From the viewpoint of reducing inductance,
Even if the center of each electrode is not on a straight line, it overlaps on the plan view
Of the two wide conductors, the narrow one is the wide one
In the plan view.

Embodiment 8 FIG. An eighth embodiment of the present invention will be described with reference to the drawings. Fig. 14
Shows a structure when the design concept of the first embodiment is applied to a snubber circuit of a plurality of self-extinguishing semiconductor elements connected in series. 1A and 1B are GTO, 2A and 2B are snubber diodes, 3A,
3B is a snubber capacitor. Focusing on GTO1A,
10A is a cooling fin (or a conductor) pressed against the anode of GTO1A, 11A is a cooling fin (or a conductor) pressed against the cathode of GTO1, and 12A and 13A are snubber capacitors 3A.
14A is a wide conductor connecting the cooling fin 10A and the anode of the snubber diode 2A, and 15A is a snubber diode 2A
Is a wide conductor connecting the cathode of the snubber capacitor 3A to the electrode 12A of the snubber capacitor 3A, and 16A is a wide conductor connecting the electrode 13A of the snubber capacitor 3A and the cooling fin 11A. For cooling of snubber diode 2A, cooling fin 10A and wide conductor
It may be realized by integration with 14A, or a cooling means such as a cooling fin may be separately added. GTO1B
Is the same as the structure for GTO1A, and the description is omitted.

FIG. 14 shows a plurality of GTOs 1A and 1B connected in series.
1 is applied to the anode and the cathode of FIG. Therefore, it is clear that the effect of reducing the inductance in the snubber circuit is equivalent to that of FIG. Also, there are four possible connection methods of snubber circuits connected in parallel to a plurality of GTOs connected in series as shown in FIG. FIG. 14 shows FIG. 15
The specific structure of (1) is shown in FIG. 15 (2). Considering the side view, for example, the combination of FIG. 1 and FIG.
It is clear that the configuration can also be made from the combination of FIG. The other FIGS. 15 (3) and 15 (4) can also be realized by a combination of the already described embodiments.

In this embodiment, a plurality of self-extinguishing semiconductor elements are connected in series. However, the present invention can be similarly applied to a series-parallel connection.

Reference Example 2 16, FIG. 17 is a diagram showing the structure of the snubber circuit of the self-turn-off semiconductor devices. FIG. 16 is a plan view and FIG. 17 is a side view, and the snubber capacitor and its connection means are omitted for the sake of explanation. The difference from FIG. 14 is that the snubber diodes 2A and 2B
Are not located at the same position in the plan view. However, as shown in FIG. 16, all the electrode surfaces are in a parallel positional relationship, the wide conductor is in a parallel positional relationship, and the snubber diode 2A and the snubber capacitor 3A (not shown) are on the center line SS with respect to the GTO 1A. If the snubber diode 2B and the not-shown snubber capacitor 3B are on the center line TT having an angle with respect to the center line SS with respect to the GTO 1B, the side view of each snubber circuit structure viewed from the direction 1 and the direction 2 is FIG. Is the same as Therefore, similarly to FIG. 1, it is apparent that the inductance in each snubber circuit can be reduced. Although FIG. 16 shows a case where the interior angle formed by the center line SS and the center line TT is a right angle, there is no necessity that the interior angle is a right angle, and there is no particular limitation.

Embodiment 9 FIG. A ninth embodiment of the present invention will be described with reference to the drawings. FIG. 18 shows self-extinguishing type semiconductor elements 1A, 1B, 1C, 1D connected in series between positive and negative buses P, N of a DC power supply 17 having an intermediate potential point C.
(Eg, GTO) and freewheeling diodes 18A, 18B, 18C, 18D connected in anti-parallel to each of them.
, The connection point between GTO1A and GTO1B and the intermediate potential point C
A clamp diode 19A connected between the GTO1C and GTO1D, a clamp diode 19B connected between the intermediate potential point C, and an output terminal O provided at a connection point between GTO1B and GTO1C. GTO1A to G
This is a three-level inverter device that can output three voltage levels of the voltages of the positive and negative buses P and N of the DC power supply 17 and the voltage of the intermediate potential point C to the output terminal O by the switching operation of the TO1D. Note that additional components such as an anode reactor, a snubber resistor, and a snubber energy regeneration circuit are omitted because they are not directly related to the present invention.

The connection of a snubber circuit for suppressing a steep voltage increase rate when the current of each GTO constituting the three-level inverter device is cut off will be described. The snubber circuit of this three-level inverter device is GTO
A snubber circuit consisting of a snubber capacitor 3A and a snubber diode 2A connected in parallel to 1A, and a clamp diode 19A
A snubber circuit consisting of a snubber diode 2B and a snubber capacitor 3B connected to the anode of the freewheel diode 18C and a snubber capacitor 3C and a snubber diode 2C connected to the cathode of the freewheel diode 18B and the cathode of the clamp diode 19B. A snubber circuit,
A snubber circuit composed of a snubber capacitor 3D and a snubber diode 2D connected in parallel to GTO1D is connected. For example, for GTO1A, as shown in FIG.
When (a) is cut off by the GTO 1A, the current is bypassed by the current (b), and the rate of voltage increase applied to the GTO 1A can be suppressed by charging the snubber capacitor 3A in the snubber circuit. The same applies to GTO1D. As for GTO1B, as shown in FIG. 19 (2), the current (a) is changed to GTO1B.
Is cut off, the current (b) is bypassed, and the charging operation of the snubber capacitor 3B in the snubber circuit can suppress the rate of voltage increase on the GTO1B. The same applies to GTO1C.

As for the snubber circuit for GTO1A and GTO1D shown in FIG. 18, any one of the embodiments of the snubber circuit structure described above can be applied as it is. But GTO1B, G
The fact that the above-described embodiment cannot be directly applied to the snubber circuit for TO1C is apparent from the difference between the current cutoff operations shown in FIGS. 19 (1) and 19 (2).

Here, the structure of the snubber circuit that can realize the reduction of the inductance particularly for GTO1B and GTO1C will be described with reference to the drawings. First, FIG. 20 shows a side view of the structure of a snubber circuit for GTO1B. 1B is GTO,
2B is a snubber diode, 3B is a snubber capacitor, 10B is a cooling fin (may be a conductor) pressed against the anode of GTO1B, and 11B is a cooling fin (may be a conductor) pressed against the cathode of GTO1B. Connected. 20
B is a cooling fin (or a conductor) of the clamp diode 19A, which is connected to the intermediate potential point C. 21B is the cooling fin of the freewheel diode 18C (may be a conductor)
It is. 12B and 13B are the electrodes of snubber capacitor 3B, 14B
Is a wide conductor connecting the cooling fin 20B and the anode of the snubber diode 2B, 15B is a wide conductor connecting the cathode of the snubber diode 2B and the electrode 12B of the snubber capacitor 3B, 16B
Is a wide conductor connecting the electrode 13B of the snubber capacitor 3B and the cooling fin 21B. The cooling of the snubber diode 2B may be realized by integrating the cooling fins 20B and the wide conductors 14B, or cooling means such as individual cooling fins may be added.

In FIG. 20, all the electrode surfaces have a parallel positional relationship and also have a linear positional relationship. In addition, it is possible to satisfy the definition of the wide conductor. Clamp diode 19A and freewheel diode 18C added to Fig. 1
Are mutually coupled, considering that the current polarity of the clamp diode 19A and the snubber diode 2B or the current polarity of the freewheel diode 18C and the shaded portion of the wide conductor 15B are opposite. Also wide conductor 15B
And 16B are arranged so as to maintain a partial but parallel positional relationship as much as possible. That is, also in this embodiment, the design concept of the first embodiment is applied as much as possible, so that the inductance in the snubber circuit can be reduced as in the first embodiment.

Next, FIG. 21 shows a side view of the structure of the snubber circuit for GTO1C. 1C is a GTO, 2C is a snubber diode, 3C is a snubber capacitor, and 10C is a cooling fin (or a conductor) pressed against the anode of the GTO 1C, and is connected to the output terminal O. 11C is a cooling fin (or a conductor) pressed against the cathode of the GTO1C, 20C is a cooling fin (or a conductor) of the clamp diode 19B,
Connected to intermediate potential point C. 21C is a cooling fin (or a conductor) of the freewheel diode 18B. 12C
, 13C is the electrode of the snubber capacitor 3C, 14C is the wide conductor connecting the cooling fin 20C and the cathode of the snubber diode 2C, 15C is the wide conductor connecting the anode of the snubber diode 2C and the electrode 12C of the snubber capacitor 3C, and 16C is This is a wide conductor connecting the electrode 13C of the snubber capacitor 3C and the cooling fin 21C. The cooling of the snubber diode 2C may be realized by integrating the cooling fins 20C and the wide conductors 14C, or cooling means such as individual cooling fins may be added.

In FIG. 21, as in FIG. 20, all electrode surfaces have a parallel positional relationship and also have a linear positional relationship. In addition, it is possible to satisfy the definition of the width of the wide conductor. Regarding the clamp diode 19B and the freewheel diode 18B added to FIG. 1, the current polarity between the clamp diode 19B and the snubber diode 2C or between the freewheel diode 18B and the hatched portion of the wide conductor 15C is opposite. If considered, they are in a mutual connection relationship. The wide conductors 15C and 16C are arranged so as to maintain a parallel positional relationship as much as possible, though partially. That is, also in this embodiment, the design concept of the first embodiment is applied as much as possible, so that the inductance in the snubber circuit can be reduced as in the first embodiment.

Of course, the other embodiments described above can be applied to the GTO1B and GTO1C snubber circuits to reduce the inductance in the snubber circuits.
For example, it goes without saying that the snubber capacitor shown in FIG. 10 may be applied to snubber capacitor 3B shown in FIG.

Embodiment 10 FIG. A tenth embodiment of the present invention will be described with reference to the drawings. Fig. 22
Are self-extinguishing semiconductor elements 1A, 1B, 1C, 1D connected in series between the positive and negative buses P, N of a DC power supply 17 having an intermediate potential point C.
(Eg, GTO) and freewheeling diodes 18A, 18B, 18C, 18D connected in anti-parallel to each of them.
, The connection point between GTO1A and GTO1B and the intermediate potential point C
A clamp diode 19A connected between the GTO1C and GTO1D, a clamp diode 19B connected between the intermediate potential point C, and an output terminal O provided at a connection point between GTO1B and GTO1C. GTO1A to G
This is a three-level inverter device that can output three voltage levels of the voltages of the positive and negative buses P and N of the DC power supply 17 and the voltage of the intermediate potential point C to the output terminal O by the switching operation of the TO1D. Note that additional components such as an anode reactor, a snubber resistor, and a snubber energy regeneration circuit are omitted because they are not directly related to the present invention.

The connection of a snubber circuit for suppressing a steep voltage rise rate when the current of each GTO constituting the three-level inverter device is cut off will be described. The snubber circuit of this device includes a snubber circuit composed of a snubber capacitor 3A and a snubber diode 2A connected in parallel to GTO1A, and a snubber circuit composed of a snubber capacitor 3B and a snubber diode 2 connected to the anode of clamp diode 19A and the cathode of GTO1B. Circuit and snubber diode 2C connected to anode of GTO1C and cathode of clamp diode 19B
And snubber circuit consisting of snubber capacitor 3C and GTO1D
Is connected to a snubber circuit composed of a snubber diode 2D and a snubber capacitor 3D connected in parallel. For example, GT
As for O1A, as shown in FIG.
When TO1A is cut off, the current is bypassed to current (b), and the charging operation of snubber capacitor 3A in the snubber circuit causes
The rate of increase in the voltage applied to O1A can be suppressed. GT
The same applies to O1D. For GTO1B,
As shown in FIG. 23 (2), when the current (a) is cut off by the GTO1B, the current (b) is bypassed, and the charging operation of the snubber capacitor 3B in the snubber circuit suppresses the rate of voltage increase on the GTO1B. Can be. The same applies to GTO1C.

For the snubber circuits for GTO1A and GTO1D shown in FIG. 22, any of the embodiments of the snubber circuit structure described above can be applied as they are. But GTO1B, G
The fact that the above-described embodiment cannot be directly applied to the snubber circuit for TO1C is evident from the difference between the current cutoff operations shown in FIGS. 23 (1) and 23 (2).

Here, the structure of the snubber circuit which can realize the reduction of the inductance particularly for GTO1B and GTO1C will be described with reference to the drawings. First, FIG. 24 shows a side view of the structure of a snubber circuit for GTO1B. 1B is GTO,
2B is a snubber diode, 3B is a snubber capacitor, 10B is a cooling fin (may be a conductor) pressed against the anode of GTO1B, and 11B is a cooling fin (may be a conductor) pressed against the cathode of GTO1B. Connected. 20
B is a cooling fin (or a conductor) of the clamp diode 19A, which is connected to the intermediate potential point C. 12B and 13B are the electrodes of the snubber capacitor 3B, 14B is a wide conductor connecting the cooling fin 11B and the cathode of the snubber diode 2B, and 15B is the anode of the snubber diode 2B and the electrode of the snubber capacitor 3B.
Wide conductor to connect with 12B, 16B is snubber capacitor 3B
This is a wide conductor connecting the electrode 13B and the cooling fin 20B. The cooling of the snubber diode 2B may be realized by integrating the cooling fins 11B and the wide conductors 14B, or cooling means such as individual cooling fins may be added.

In FIG. 24, all the electrode surfaces have a parallel positional relationship and also have a linear positional relationship. In addition, it is possible to satisfy the definition of the width of the wide conductor. The clamp diode 19A added to FIG. 1 has a mutual coupling relationship in consideration of the fact that the current polarity between the clamp diode 19A and the hatched portion of the wide conductor 15B is opposite. The wide conductors 15B and 16B are arranged so as to maintain a parallel positional relationship as much as possible, though partially. That is, also in this embodiment, the design concept of the first embodiment is applied as much as possible, so that the inductance in the snubber circuit can be reduced as in the first embodiment.

Next, FIG. 25 shows a side view of the structure of the snubber circuit for GTO1C. 1C is a GTO, 2C is a snubber diode, 3C is a snubber capacitor, and 10C is a cooling fin (or a conductor) pressed against the anode of the GTO 1C, and is connected to the output terminal O. 11C is a cooling fin (or a conductor) pressed against the cathode of the GTO1C, 20C is a cooling fin (or a conductor) of the clamp diode 19B,
Connected to intermediate potential point C. 12C and 13C are electrodes of the snubber capacitor 3C, 14C is a wide conductor connecting the cooling fin 10C and the anode of the snubber diode 2C, 15C is a wide conductor connecting the cathode of the snubber diode 2C and the electrode 12C of the snubber capacitor 3C, 16C Is a wide conductor connecting the electrode 13C of the snubber capacitor 3C and the cooling fin 20C. The cooling of the snubber diode 2C may be realized by integrating the cooling fins 10C and the wide conductors 14C, or cooling means such as individual cooling fins may be added.

In FIG. 25, as in FIG. 24, all electrode surfaces have a parallel positional relationship and also have a linear positional relationship. In addition, it is possible to satisfy the definition of the width of the wide conductor. The clamp diode 19B added to FIG. 1 has a mutual coupling relationship in consideration of the fact that the current polarity between the clamp diode 19B and the hatched portion of the wide conductor 15C is in the opposite direction. The wide conductors 15C and 16C are arranged so as to maintain a parallel positional relationship as much as possible, though partially. That is, also in this embodiment, the design concept of the first embodiment is applied as much as possible, so that the inductance in the snubber circuit can be reduced as in the first embodiment.

It is needless to say that the other embodiments described above can be applied to the GTO1B and GTO1C snubber circuits to reduce the inductance in the snubber circuits.
For example, it goes without saying that the snubber capacitor shown in FIG. 10 may be applied to snubber capacitor 3C shown in FIG.

Embodiment 11 FIG. An eleventh embodiment of the present invention will be described with reference to the drawings. Figure 2
6 and FIG. 27 show the structure of a snubber circuit of a self-extinguishing semiconductor device which is implemented by partially modifying the design concept of the first embodiment. 1
Is a GTO, 2 is a snubber diode, 3 is a snubber capacitor, 10 is a cooling fin (or a conductor) pressed against the anode of the GTO1, 11 is a cooling fin (or a conductor) pressed against the cathode of the GTO1, 12, 13 Is a wide conductor connecting the cooling fin 11 and the anode of the snubber diode 2, 15 is a wide conductor connecting the cathode of the snubber diode 2 and the electrode 12 of the snubber capacitor 3, and 16 is a snubber capacitor. This is a wide conductor connecting the third electrode 13 and the cooling fin 11.

The difference from FIG. 1 is that the distance between the electrodes of the GTO 1 is considerably larger than the sum of the distance between the electrodes of the snubber diode 2 and the distance between the electrodes 12 and 13 of the snubber capacitor 3. In such a case, in order to reduce the inductance in the snubber circuit, as shown in FIGS. 26 and 27, all the electrode surfaces are arranged in a linear positional relationship, and the width of the wide conductor is defined. Comply with wide conductors 15 and 16, wide conductor 14
It is advantageous to place 16 as close together as possible to have an interconnected relationship.

Embodiment 12 FIG. A twelfth embodiment of the present invention will be described with reference to the drawings. Figure 28
9 shows the structure of a snubber circuit of a self-extinguishing semiconductor device implemented by partially modifying the design concept of the first embodiment. 1 is GT
O, 2 is a snubber diode, 3 is a snubber capacitor, 10
Is a cooling fin (or a conductor) pressed against the GTO 1 and the snubber diode 2, 11 is a cooling fin (or a conductor) pressed against the cathode of the GTO 1, 12, 13 are electrodes of the snubber capacitor 3, and 15 is a snubber diode 2. Is a wide conductor connecting the negative electrode of the snubber capacitor 3 to the electrode 12 of the snubber capacitor 3, and 16 is a wide conductor connecting the electrode 13 of the snubber capacitor 3 and the cooling fin 11.

The difference from FIG. 1 is that the GTO 1 and the snubber diode 2 are housed in the same press-contact structure. In the figures used in the above-described embodiment, the GTO1 and the snubber diode 2 have large GTO1 electrode diameters, and when the GTO1 and the snubber diode 2 are housed in the same pressure contact structure, uniform contact between the electrode surfaces is impossible. Was assumed. That is, it is assumed that the GTO 1 and the snubber diode 2 are housed in different press-contact structures. However, in order to reduce the inductance in the snubber circuit when the diameters of the electrode surfaces of the GTO 1 and the snubber diode 2 are in a condition that can be accommodated in the same pressure welding structure as shown in FIG. It is advantageous to arrange so that all the electrode surfaces are in a linear positional relationship, observe the rules for the width of the wide conductor, and arrange the wide conductors 15 and 16 as close as possible to have a mutual coupling relationship. It is.

Embodiment 13 FIG. In the drawings used in the description of the above-described embodiment, the self-extinguishing type semiconductor element, the diode, the cooling fin, and the like are pressed into contact with each other.
A press-contact means for ensuring heat conduction and making the temperature distribution uniform must always be added in practical use. Furthermore, the insertion of an insulator for guaranteeing the insulation distance or the edge surface distance is omitted because it depends on the voltage applied to the self-extinguishing type semiconductor element. No. For example, in FIG. 1, especially for an insulator inserted between the wide conductor 15 and the wide conductor 16, if a dielectric having a large dielectric constant is inserted, the capacitance of the snubber capacitor is equivalently increased, and The voltage increase rate when the arc-shaped semiconductor element interrupts the current can be suppressed, and the loss of the self-extinguishing semiconductor element can be reduced.

[0074]

According to the power converter of the present invention, the inductance of the snubber circuit can be reduced, and therefore, the loss when the self-extinguishing type semiconductor element is cut off can be reduced.

The two electrodes of the snubber capacitor
The wide conductors connected to each other are paired in parallel close to each other,
When inserting a dielectric between the pair of wide conductors
Can equivalently increase the capacity of the snubber capacitor and reduce the loss when the self-extinguishing type semiconductor element is cut off.

Further , the self-extinguishing type semiconductor elements are connected in series.
In the case where a plurality of power supply devices are connected in series or in parallel, the inductance of the snubber circuit in a high-voltage or high-power power converter can be reduced, and the loss when the self-extinguishing semiconductor device is cut off can be reduced.

Also, the power converter is a three-level inverter.
In the three-level inverter, the inductance of the snubber circuit can be reduced in the three-level inverter, and the loss when the self-extinguishing type semiconductor element is cut off can be reduced.

[0078]

[Brief description of the drawings]

FIG. 1 is a side view of a snubber circuit structure according to a first embodiment of the present invention.

FIG. 2 is a plan view of a snubber circuit structure according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating the center of a snubber capacitor electrode.

FIG. 4 is a diagram illustrating a structural model of a snubber circuit.

FIG. 5 is a diagram showing inductance characteristics in a snubber circuit.

FIG. 6 is a side view of a snubber circuit structure according to a second embodiment of the present invention.

FIG. 7 is a plan view of a snubber circuit structure according to a second embodiment of the present invention.

FIG. 8 is a side view of a snubber circuit structure according to a third embodiment of the present invention.

FIG. 9 is a side view of a snubber circuit structure according to a fourth embodiment of the present invention.

FIG. 10 is a side view of a snubber circuit structure according to a fifth embodiment of the present invention.

FIG. 11 is a side view of a snubber circuit structure according to a sixth embodiment of the present invention.

FIG. 12 is a side view of a snubber circuit structure .

FIG. 13 is a plan view of a snubber circuit structure according to a seventh embodiment of the present invention.

FIG. 14 is a plan view of a snubber circuit structure according to an eighth embodiment of the present invention .

FIG. 15 is a diagram illustrating a connection example of a snubber circuit to a self-extinguishing type semiconductor element connected in series.

FIG. 16 is a plan view of a snubber circuit structure .

FIG. 17 is a side view of a snubber circuit structure .

FIG. 18 is a circuit configuration diagram of a three-level inverter device according to a ninth embodiment of the present invention.

FIG. 19 is a diagram illustrating the operation of a snubber circuit applied to a three-level inverter device according to a ninth embodiment of the present invention.

FIG. 20 is a side view of a snubber circuit structure according to a ninth embodiment of the present invention.

FIG. 21 is a side view of a snubber circuit structure according to a ninth embodiment of the present invention.

FIG. 22 is a circuit configuration diagram of a three-level inverter device according to a tenth embodiment of the present invention.

FIG. 23 is a diagram illustrating the operation of the snubber circuit applied to the three-level inverter device according to the tenth embodiment of the present invention.

FIG. 24 is a side view of a snubber circuit structure according to a tenth embodiment of the present invention.

FIG. 25 is a side view of a snubber circuit structure according to a tenth embodiment of the present invention.

FIG. 26 is a side view of a snubber circuit structure according to an eleventh embodiment of the present invention.

FIG. 27 is a side view of a snubber circuit structure according to an eleventh embodiment of the present invention.

FIG. 28 is a side view of a snubber circuit structure according to a twelfth embodiment of the present invention.

FIG. 29 is a diagram showing a conventional snubber circuit structure.

FIG. 30 is a diagram illustrating the operation of a snubber circuit applied to a self-extinguishing semiconductor device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Self-extinguishing semiconductor element 2 Snubber diode 3 Snubber capacitor 10, 11 Cooling fin 12, 13 Electrode of snubber capacitor 14, 15, 16 Wide conductor

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-227737 (JP, A) JP-A-63-177024 (JP, U) JP-A-59-60887 (JP, U) JP-A-59-60887 60888 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02M 1/06 H02M 7/48 H02M 1/00

Claims (6)

(57) [Claims] 1. A self-extinguishing type semiconductor device, a snubber circuit connected to a bypass circuit of the self-extinguishing type semiconductor device, comprising a series body of a snubber diode and a snubber capacitor, and one end of the self-extinguishing type semiconductor device. To the other end
A first wide conductor connected to a diode, one end of which is
The other end of the self-extinguishing type semiconductor device is connected to the above snubber capacitor.
A second wide conductor to be connected, and one end having the snubber die
The other end of the diode is connected to the snubber capacitor.
A plurality of band-shaped wide conductors each having a wide conductor, and a center of the self-extinguishing semiconductor device and the snubber diode.
Line connecting the center of the diode and the center of the snubber diode
And a line segment connecting the centers of the electrodes of the snubber capacitor,
The center of the snubber capacitor electrode and the self-extinguishing half
The line connecting the centers of the conductor elements should be included on the same plane
The self-extinguishing type semiconductor element, the snubber diode and
And the snubber capacitors are arranged, and the wide conductors are all arranged in a parallel positional relationship. 2. The width of the wide conductor is such that it is interconnected .
Power converter according to claim 1, characterized in that it is that is at least two smallest ones width of the width of the electrode surface more. 3. The method of claim 2, wherein two of the wide conductors are close to each other.
And the current flows in the opposite direction in these wide conductors
The power conversion device according to claim 1 or 2 , wherein the power conversion device is configured as described above. 4. A contact between two electrodes of said snubber capacitor.
The wide conductors to be continued are paired in parallel close to each other,
The feature is that a dielectric is inserted between the pair of wide conductors.
The power converter according to any one of claims 1 to 3 . 5. The self-extinguishing type semiconductor element is connected in series or
5. A method according to claim 1, wherein a plurality of serially-parallel connections are provided.
The power converter according to claim 1 . 6. The power conversion device is a three-level inverter.
The method according to any one of claims 1 to 6, wherein
Power conversion device.