JPH07147784A - Power converter - Google Patents

Abstract

PURPOSE:To downsize a device and lower the price by lessening wiring inductance and lessening the capacity of an overvoltage suppressing circuit. CONSTITUTION:This relates to a power converter where first to fourth semiconductor switch elements 71-74 each accommodated in a flat case are connected in series together with coolers-cum-conductors 21-28 arranged on both sides of each, and both ends of this series circuit are connected to a DC power source 13, and also the mutual junctions between second and third semiconductor switch elements 72 and 73 is made the output terminal 14 of a power converting circuit. The first and fourth semiconductor switch elements 71 and 74 and coolers-cum- conductors 21 and 22, and 27 and 28 on both sides of them are welded with each other by a press device, and besides the second and third semiconductor switch elements 72 and 73 and coolers-cum-conductors 23 and 24,and 25 and 26 on both sides of them are pressed with each other by a press device, and also the first and second press devices are arranged close to each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power converter having a plurality of semiconductor switch elements housed in a flat case.

[0002]

2. Description of the Related Art FIG. 12 shows a conventional technique of this type of power conversion device, which corresponds to one phase of a three-level inverter, for example. In the figure, the reverse conducting GTO thyristors 71'-74 'housed in the flat case are sandwiched by the cooling body / conductors 21-28 on the upper and lower sides, respectively.
Further, they are electrically connected in series via the conductors 41 to 43. Then, the whole of these is the lower base plate 5, the upper base plate 6, the insulators 31 and 32, the spring 12, and the shaft 8.
It is pressed by a certain load from the vertical direction by a single pressing device composed of 1,82.

In general, when operating a semiconductor switching element, an overvoltage suppressing circuit generated at the time of switching is connected to both ends of a power source in the immediate vicinity of the semiconductor switching element, and from the viewpoint of reducing wiring inductance, the power source, the semiconductor switching element, and the overvoltage. It is necessary to wire the closed circuit composed of the suppression circuit as short as possible. In this respect,
In the conventional technique of FIG. 12, both ends of the DC power supply 13 are connected to the uppermost and lowermost cooling body / conductors 21 and 28, and both ends of an overvoltage suppressing circuit including the diode 10 and the capacitor 9 are connected. In addition, 11 is a resistance for discharge,
Reference numeral 14 is an output terminal of the power conversion circuit.

[0004]

However, according to the above-mentioned prior art, four reverse conducting GTO thyristors 71'-7 are used.
Since there is a wiring length that is almost twice the total length of the height of the entire 4 ′, the height of the eight cooling bodies / conductors 21 to 28, and the height of the three conductors 41 to 43 as a whole. However, there is a problem in that the wiring inductance becomes large and a sufficient suppressing effect cannot be obtained despite the provision of the overvoltage suppressing circuit. Therefore, in order to increase the stored energy, the capacity of the overvoltage suppressing circuit is increased, resulting in a larger size and higher price.

The present invention has been made to solve the above problems, and an object of the present invention is to shorten the wiring length of the circuit to reduce the wiring inductance and to reduce the capacitance of the overvoltage suppressing circuit. The present invention is to provide a power converter.

[0006]

In order to achieve the above object, the first aspect of the present invention is to provide a cooling body / conductor in which first to fourth semiconductor switching elements respectively housed in a flat case are arranged on both sides thereof. Are connected in series with each other, and both ends of this series circuit are connected to a DC power source, and second and third
In the power conversion device in which the interconnection point of the semiconductor switch elements is used as the output terminal of the power conversion circuit, the first and fourth semiconductor switch elements and the cooling body / conductor on both sides thereof are pressure-welded by the first pressing device, In addition, the second and third semiconductor switch elements and the cooling body / conductor on both sides of these are pressed against each other by the second pressing device, and the first and second pressing devices are arranged close to each other. Characterize.

A second invention is the same as the first invention,
A clamp diode is connected to the conductors on one side of each of the first and fourth semiconductor switch elements, these diodes are connected in the forward direction through the conductors, and the first and second filter capacitors are connected in parallel to the DC power supply. Are connected in series, and the interconnection point of these capacitors is connected to the interconnection point of the diode.

In a third aspect based on the first or second aspect, the first and second pressing devices have a shaft extending along the series direction of the semiconductor switch elements, which are in pressure contact with each other, around the semiconductor switch element. It is characterized in that the shaft of at least one of the pressing devices is arranged so as to be displaced in the front-rear direction with respect to the shaft of the other pressing device adjacent to this shaft.

[0009]

In the first or second invention, among the four semiconductor switching elements connected in series, the first and fourth semiconductor switching elements located at both ends of the four semiconductor switching elements are pressed by the first press device, The second and third semiconductor switch elements are pressed together by the second press machine, and the first and fourth semiconductor switch elements are connected to both ends of the DC power source.
By connecting the second semiconductor switching elements and the third and fourth semiconductor switching elements in a short distance, the wiring inductance of the entire circuit can be shortened and the capacitance of the overvoltage suppressing circuit can be reduced. You can

In the third invention, by shifting at least one shaft of the first and second pressing devices back and forth, the wiring length between the semiconductor switch elements between the respective pressing devices can be shortened and the wiring inductance can be reduced. One phase can be reduced.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. First, FIG. 1 shows an embodiment of the first invention. In the figure, the first to fourth semiconductor switch elements 71 to 74 housed in the flat case are connected in series,
The interconnection point of the second and third semiconductor switch elements 72 and 73, that is, the conductor 42 serves as the output terminal of the power conversion circuit. Further, cooling body / conductors 21 to 28 are arranged on both sides of the semiconductor switch elements 71 to 74 in the vertical direction.

First and fourth semiconductor switch elements 71, 7
4 and the cooling body and conductors 21, 22, 27, on both sides of each
28 is a lower base plate 51, an upper base plate 61, a spring 12
The upper and lower parts are pressed against each other by the first press device including the first insulator 31, 32, 35 and the shafts 81, 82.
Here, the shafts 81 and 82 are the semiconductor switching elements 7
1, 74 are arranged along the series direction (vertical direction). In addition, the second and third semiconductor switch elements 72, 73
And cooling body / conductors 23, 24, 25, 2 on both sides of each
6 and the conductor 42 include a lower base plate 52, an upper base plate 62,
Spring 122, insulators 33 and 34, and shafts 83 and 84
The upper and lower portions are pressed against each other by a second pressing device composed of. The shafts 83 and 84 are also arranged along the series direction of the semiconductor switch elements 72 and 73, similarly to the above.

Then, the adjacent cooling body / conductors 21 and 28
Is connected to both ends of the DC power supply 13, and the cooling body and conductor 2 are connected.
A power conversion circuit as shown in FIG. 2 is configured by connecting between 2, 23 and between 26, 27 by a conductor. The first and second pressing devices are arranged close to each other, and the space between the cooling body / conductors 22 and 23 and
The wiring length between 6 and 27 is considered to be as short as possible.

FIG. 3 is a more specific example of the embodiment of FIG. 1, in which reverse conducting GTO thyristors 71'-74 'are used as the semiconductor switching elements 71-74 of FIG. An overvoltage suppressing circuit composed of a diode 10 and a capacitor 9 is connected between 28. FIG. 4 is a circuit diagram corresponding to FIG. In addition,
The resistor 11 in FIG. 4 is omitted in FIG. 3 for convenience.

According to this embodiment, since the DC power supply 13 is connected between the adjacent cooling body / conductors 21 and 28, the conductors at both ends of the DC power supply 13 and the both ends of the overvoltage suppressing circuit should be shortened. Therefore, the wiring inductance of the power conversion circuit can be reduced.

Next, FIG. 5 shows an embodiment of the second invention. The same components as those in FIGS. 1 and 3 are designated by the same reference numerals. In FIG. 5, 161 is a first clamp diode (coupling diode) connected to the cooling body / conductor 22 and 162 is a second clamp diode (coupling diode) connected to the cooling body / conductor 27.
Clamp diode of these, these diodes 16
1, 162 are built in a flat case and connected in series and in the forward direction by a conductor 44. Also, 151,15
Reference numeral 2 denotes a smoothing filter capacitor connected in series to both ends of the DC power supply 13, and the interconnection point of the capacitors 151 and 152 is connected to the conductor 44. In addition, in FIG.
FIG. 6 is a circuit diagram corresponding to FIG. 5.

FIG. 7 is a more specific example of the embodiment of FIG. 5, in which reverse conducting GTO thyristors 71'-74 'are used as the semiconductor switching elements 71-74 of FIG.
An overvoltage suppressing circuit including diodes 101 and 102 and capacitors 91 and 92 is connected between the cooling body / conductors 21 and 28 and the conductor 44. FIG. 8 is a circuit diagram corresponding to FIG. 7. The resistor 1 in FIG.
11, 112 are also omitted in FIG. 7 for convenience.

Also in this embodiment, since the series circuit of the DC power supply 13 and the filter capacitors 151 and 152 is connected between the adjacent cooling body / conductors 21 and 28, the wiring length at both ends thereof is shortened. The wiring inductance can be reduced. In addition, the clamp diode 16
1 and 162 are connected by the conductor 44, and the overvoltage suppressing circuit is connected within the shortest distance between the conductor 44 and the cooling body / conductors 21 and 28, which is also effective in reducing the wiring inductance.

FIG. 9 is a plan view of a main portion showing an embodiment of the third invention, and the same components as those in the above embodiment are designated by the same reference numerals. That is, in this embodiment, the shafts 81 and 82 of the first pressing device are tilted by an angle α with respect to the cooling body / conductor (only the cooling body / conductor 22 which is the frontmost in the plan view is shown). In addition, the shafts 83 and 82 are arranged so as to overlap each other when viewed from the front, in other words, the shafts 81 and 82 are arranged so as to be displaced in the front-rear direction with respect to the shafts 83 and 84 of the second press device. . Although not shown, the shafts 81 and 82 of the first pressing device may be left as they are, and the shafts 83 and 84 of the second pressing device may be displaced in the front-rear direction.

With this structure, as shown in FIG. 11, the shafts 81 to 8 of the first and second pressing devices are formed.
As compared with the case where 4 are arranged in a straight line,
Since the distance between 2 and 23 and the distance between the cooling body / conductors 27 and 26 can be shortened, the wiring inductance can be further reduced.

FIG. 10 shows another embodiment of the third invention, in which the shafts 81, 82 and 83, 84 for both the first and second press devices are used as the cooling body and conductor. The shafts 83, 8 are tilted by an angle α and seen from the front.
It is arranged so that the two overlap. Also in this embodiment, the same effect as in FIG. 9 can be obtained. The embodiment of FIGS. 9 and 10 is the first or second embodiment.
Can be applied to any of the embodiments of the invention.

In each of the above embodiments, the semiconductor switch elements 71 to 74 may be thyristors other than the reverse conducting GTO thyristors, power transistors or the like.

[0023]

As described above, according to the first or second aspect of the invention, the first and fourth semiconductor switching elements located at both ends of the four semiconductor switching elements connected in series are adjacent to each other to form the first semiconductor switching element. And presses the other second and third semiconductor switch elements with the second press device, and the first and second press devices are arranged close to each other, and the first and second press devices are arranged in close proximity to each other. Since the semiconductor switching device of No. 4 is connected to both ends of the DC power supply, the wiring length at both ends of the DC power supply and both ends of the overvoltage suppressing circuit connected in parallel with the DC power supply can be shortened. Therefore, the wiring inductance can be reduced, and an overvoltage suppressing circuit having a small capacity can be used, so that the size and weight of the device can be reduced, the cost can be reduced, and the efficiency can be improved.

According to the third invention, the first and second
The wiring inductance can be further reduced by further shortening the distance between the pressing devices.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a first invention.

FIG. 2 is a circuit diagram corresponding to FIG.

FIG. 3 is a diagram showing a specific configuration of the embodiment of FIG.

FIG. 4 is a circuit diagram corresponding to FIG.

FIG. 5 is a configuration diagram showing an embodiment of the second invention.

FIG. 6 is a circuit diagram corresponding to FIG.

FIG. 7 is a diagram showing a specific configuration of the embodiment of FIG.

8 is a circuit diagram corresponding to FIG. 7. FIG.

FIG. 9 is a plan view of a main portion showing an embodiment of the third invention.

FIG. 10 is a plan view of a main portion showing another embodiment of the third invention.

FIG. 11 is a plan view of a main portion for comparison with the examples of FIGS. 9 and 10.

FIG. 12 is a configuration diagram showing a conventional technique.

[Explanation of symbols]

 9 Capacitor 10 Diode 11 Resistor 13 DC power supply 14 Output terminal 21-28 Cooling body and conductor 31-35 Insulator 42,44 Conductor 51,52 Lower base plate 61,62 Upper base plate 71-74 Semiconductor switch element 71'-74 ′ Reverse conduction GTO thyristor 81-84 Shaft 121,122 Spring 151,152 Filter capacitor 161,162 Clamp diode

Claims (3)

[Claims] 1. A first to a fourth semiconductor switch element, each housed in a flat case, are connected in series together with a cooling body / conductor arranged on both sides thereof, and both ends of this series circuit are connected to a DC power source. In addition, in the power conversion device in which the interconnection point of the second and third semiconductor switching elements serves as the output terminal of the power conversion circuit, the first and fourth semiconductor switching elements and the cooling body / conductor on both sides thereof are 1 is pressed by the press machine, and
The second and third semiconductor switch elements and the cooling body / conductor on both sides of these are pressed against each other by the second pressing device, and the first and second pressing devices are arranged close to each other. Power conversion device. 2. The power converter according to claim 1, wherein a clamp diode is connected to the conductors on one side of each of the first and fourth semiconductor switch elements, and these diodes are connected in the forward direction via the conductors. At the same time, a series circuit of the first and second filter capacitors is connected in parallel to the DC power source, and the interconnection point of these capacitors is connected to the interconnection point of the diode. 3. The power conversion device according to claim 1, wherein the first and second pressing devices are provided with shafts along the series direction of the semiconductor switch elements, which are in pressure contact with each other, around the semiconductor switch element. A power conversion device in which the shaft of at least one of the pressing devices is arranged so as to be displaced in the front-rear direction with respect to the shaft of the other pressing device adjacent to this shaft.