JP3641974B2 - Power converter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a power conversion device such as an inverter device to which a self-extinguishing semiconductor element is applied, and in particular, with respect to the shape of a component of the snubber circuit that is a protection circuit for the self-extinguishing semiconductor element, The present invention relates to a snubber circuit structure with improved voltage characteristics.
[0002]
[Prior art]
FIG. 4 is a side view showing an arrangement and connection method of a snubber circuit of a conventional power conversion device disclosed in, for example, Japanese Patent Laid-Open No. 8-126302, in particular, a self-extinguishing semiconductor element.
[0003]
In FIG. 4, a GTO (Gate Turn-off) thyristor (hereinafter abbreviated as GTO) is taken up as an example of the self-extinguishing semiconductor element 1, but if the electrode surface is a flat type (pressure contact is possible), the reverse will occur. The present invention can also be applied to a conductive GTO thyristor, IGBT, SI thyristor, SIC and the like. Note that additional components used in a free wheel diode, a snubber resistor, a snubber energy regeneration circuit, and the like are omitted. 1 is a GTO, 2 is a flat snubber diode, 3 is a snubber capacitor, 10 is a cooling fin pressed against the anode of the GTO 1 (may be a conductor), 11 is a cooling fin pressed against the cathode of the GTO 1 (may be a conductor) , 12 and 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) and the anode of the snubber diode 2, and 15 is the cathode of the snubber diode 2 and the snubber capacitor 3. A strip-shaped wide conductor for connecting the electrode 12, 16 is a strip-shaped wide conductor for connecting the electrode 13 of the snubber capacitor 3 and the cooling fin 11 (extension of the cathode of the GTO 1).
[0004]
In the power converter having such a configuration, the strip-shaped wide conductor 15 that connects the cathode of the snubber diode 2 and the electrode 12 of the snubber capacitor 3 that are in a parallel positional relationship, and the electrode 13 of the snubber capacitor 3 and the cooling fin 11 are connected. In order to reduce the inductance of the snubber circuit, the gap with the strip-shaped wide conductor 16 is made as small as possible.
[0005]
[Problems to be solved by the invention]
Since the conventional power converter is configured as described above, even when a GTO having an electrical rating of 6 kV, 6 kA or more is applied and used for a power converter having a DC voltage of 1.5 kV, for example, Japanese Industrial Standard JIS C 0704 -As described in 1995, it is necessary to secure a spatial distance of 14 mm or more, and the interval between the wide conductor 15 and the wide conductor 16 is 14 mm or more, or between the wide conductor 15 and the wide conductor 16. An insulator is interposed, and the size of the insulator is made larger than either the wide conductor 15 or the wide conductor 16, and the thickness of the insulator is also taken into consideration, and a spatial distance of 14 mm or more is ensured. . When the DC voltage is used at a higher level, it is necessary to further increase the spatial distance.
[0006]
Now, when an insulator is interposed between the wide conductor 15 and the wide conductor 16 and an attempt is made to narrow the gap between the wide conductor 15 and the wide conductor 16, the insulator to be used having a high dielectric breakdown strength is selected. In addition, since the wide conductor 15 and the wide conductor 16 geometrically form a flat plate capacitor, an unequal electric field is generated at the ends of the wide conductor 15 and the wide conductor 16 and strong at the ends. An electric field part is generated, and a partial discharge may occur. The occurrence of the partial discharge has problems such as malfunctioning of the control circuit of the power conversion device and the possibility of causing insulation deterioration of the insulator.
The present invention has been made to solve the above-described problems, and an object thereof is to improve the withstand voltage characteristics of the snubber circuit of the power converter.
[0007]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention is directed to a parallel wide conductor (a wide conductor connecting a snubber diode cathode and a snubber capacitor electrode, and a snubber capacitor electrode and a self-extinguishing semiconductor element). Each end portion of the wide conductor connecting the cathode) is chamfered in the opposite direction to have R or curvature.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a perspective view of a wide conductor 15 and a wide conductor 16 according to a first embodiment of the present invention. Each end of the wide conductor is chamfered in the opposite direction.
[0009]
FIG. 2 is a perspective view of the wide conductor 15 and the wide conductor 16 according to the second embodiment of the present invention. R is attached to each end of the wide conductor in the opposite direction.
FIG. 3 is a perspective view of the wide conductor 15 and the wide conductor 16 according to the third embodiment of the present invention. Curvature is provided in the opposite direction at each end of the wide conductor.
[0010]
【The invention's effect】
By chamfering each end of the wide conductors arranged in parallel in opposite directions and taking R or providing curvature, the electric field at the end can be relaxed and the occurrence of partial discharge can be prevented. .
[Brief description of the drawings]
FIG. 1 is a perspective view of a wide conductor according to a first embodiment of the present invention.
FIG. 2 is a perspective view of a wide conductor showing a second embodiment of the present invention.
FIG. 3 is a perspective view of a wide conductor showing a third embodiment of the present invention.
FIG. 4 is a side view of a conventional snubber circuit structure.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Self-extinguishing type | mold semiconductor element, 2 ... Snubber diode, 3 ... Snubber capacitor, 10, 11 ... Cooling fin, 12, 13 ... Snubber capacitor electrode, 14, 15, 16 ... Wide conductor.

Claims (1)

A self-extinguishing semiconductor element, a snubber circuit connected to the self-extinguishing semiconductor element, and a plurality of strip-shaped wide conductors connecting the self-extinguishing semiconductor element and the snubber circuit, A power conversion device, wherein chamfers or curvatures are respectively provided at opposing ends of the wide conductors arranged in parallel.

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