JP2001135547A - Snubber capacitor for semiconductor module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to increase an absorption effect of serge voltage in a snubber capacitor and improve fixing force of the capacitor in mounting. SOLUTION: Tube-structured tube terminals 12 and 13 joined to semiconductor element electrodes 15 and 16 in a semiconductor module 14 and located in a concentric state with the semiconductor module 14 are passed and mounted in a capacitor body 11a, and the capacitor body 11a can be fixed with bolts 1A and 1B that pass through the tube terminals 12 and 13. In this way, the capacitor 11 can be mounted directly to the semiconductor element electrodes 15 and 16, so the size of the snubber capacitor is made small in an inverter circuit, and inductance in wiring of the snubber circuit can be reduced to a maximum. An increase in switching voltage applied to the semiconductor element electrodes 15 and 16 can be limited and reliability in inverter unit can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a snubber capacitor for a semiconductor module which is used for a large inverter device such as a power converter and is installed to suppress an increase in a switching voltage of a semiconductor module element.

[0002]

2. Description of the Related Art Conventionally, a terminal configuration of a snubber capacitor used in a semiconductor module of a large-sized inverter device has a configuration as described in Japanese Utility Model Laid-Open No. 7-10956, for example. Further, the details will be described with reference to FIG. 4. Reference numeral 41 denotes a resin-molded film capacitor, and reference numerals 42 and 43 denote a pair of flat terminals.

[0003]

However, in the above-described conventional capacitor configuration, when the capacitor capacitance is 1 μF or more, the shape of the capacitor element becomes large and the weight increases, so that the entire inverter unit becomes large, and the snubber circuit has a large size. As a result of increasing the inductance, there is a problem that the snubber effect is reduced and the fixing strength due to the one-sided structure is insufficient.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned conventional problems, and to improve the mounting effect on the surge voltage absorbing effect of the snubber capacitor and increase the fixed strength of the capacitor in a mounting surface for a semiconductor module. It is to provide.

[0005]

According to a first aspect of the present invention, there is provided a snubber capacitor for a semiconductor module connected to a semiconductor element electrode of the semiconductor module. A cylindrical terminal having a cylindrical structure concentrically arranged with the semiconductor element electrode is provided in a state penetrating inside the capacitor body, and the capacitor body can be fixed to the semiconductor element electrode by a bolt penetrating the cylindrical terminal.

As described above, the cylindrical terminal having the cylindrical structure concentrically arranged with the semiconductor element electrode is provided so as to penetrate the capacitor body, and the capacitor main body can be fixed to the semiconductor element electrode by the bolt penetrating the cylindrical terminal. Therefore, the wiring inductance between the capacitor and the semiconductor element can be reduced. In other words, since the capacitor can be directly attached to the semiconductor element electrode, when applied to an inverter circuit, miniaturization can be realized, and at the same time, the wiring inductance of the snubber circuit can be reduced to the utmost limit, and a rise in switching voltage applied to the semiconductor element electrode is suppressed. As a result, the reliability of the inverter device can be improved. In addition, since the capacitor can be coaxially fixed to the semiconductor element electrode with the cylindrical terminal coaxially, the fixing strength of the capacitor can be improved.

According to a second aspect of the present invention, there is provided a snubber capacitor for a semiconductor module according to the first aspect, wherein the capacitor body has a cylindrical terminal and a flat plate terminal, and the flat terminals of the plurality of capacitor bodies are connected in series. Thus, since the capacitor body has the cylindrical terminal and the flat plate terminal of the flat plate structure, and the flat terminals of the plurality of capacitor bodies are connected in series, the pitch between the cylindrical terminals of the plurality of capacitor bodies can be adjusted, The applicability to various types of semiconductor modules is expanded, and at the same time, a capacitor with a high breakdown voltage can be easily realized by connecting the capacitors in series.

According to a third aspect of the present invention, there is provided a snubber capacitor for a semiconductor module according to the first or second aspect, wherein the cylindrical terminal is formed by a winding core of a wound-type evaporated film capacitor element. As described above, since the cylindrical terminal is formed by the winding core of the wound-type vapor-deposited film capacitor element, the heat conductivity from the inside of the capacitor is increased, the heat radiation can be improved, and the life characteristics of the capacitor are improved. In addition, when the core is made of a metal having high rigidity, a corona generation voltage rise phenomenon occurs, and the effect of improving the self-healing characteristics and the corona generation characteristics can be obtained.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a perspective view showing a snubber capacitor for a semiconductor module according to a first embodiment of the present invention.

As shown in FIG. 1, this snubber capacitor 11 penetrates cylindrical terminals 12 and 13 having a cylindrical structure concentrically arranged with semiconductor element electrodes 15 and 16 of a semiconductor module 14 in a resin molded capacitor body 11a. It is provided in the state where it was done. On the other hand, the semiconductor module 14 of the inverter is provided with DC electrodes 15 and 16 having a built-in nut and an AC electrode 17. Also, the capacitor body 11a
Are bolts 1A, 1B penetrating cylindrical terminals 12, 13.
Can be fixed to the semiconductor element electrodes 15 and 16. In this case, the snubber capacitor 11 is connected to the bolt 1A,
DC power supply terminals (connection wires with terminals) 18 and 1
9 and fixed to the electrodes 15 and 16 on the semiconductor module 14 so as to be fastened together with the cylindrical terminals 12 and 13 of the capacitor. Since the semiconductor module 14 in FIG. 1 is an example of a series configuration of semiconductor elements of two inverters, two sets of units are required for a single-phase inverter, and three sets of three-phase inverters are required.

In the above inverter configuration,
The surge voltage at the time of switching off of the semiconductor module 14 is proportional to the wiring inductance between the capacitor 11 and the semiconductor module 14. In this embodiment, the wiring length between the capacitor 11 and the semiconductor module 14 can be substantially reduced to only the length of the electrodes 12 and 13 of the capacitor.

The cylindrical terminals 12, 13 according to this embodiment
The inductance value at an electrode length of 22 mm is extremely small at 1 μH or less. In an experimental example applied to a DC voltage of 800 V and a 50 kVA inverter, the off-state voltage rise can be suppressed to 10 V or less even in a state where a switching current exceeding 250 A flows to a capacitor having a capacity of 1.5 μF. As a result, a reduction effect of 40 V was obtained as compared with 50 V. The external dimensions of the capacitor at this time are 50 ×
It is realized by adopting an unprecedented flat element with 70 × 20 mm and cylindrical terminal length of 22 mm.
It was tightened to 0 N · cm. As a result, from the viewpoint of earthquake resistance, the conventional configuration required reinforcement with fixing terminals, but no additional measures were required during mounting.

A second embodiment of the present invention will be described with reference to FIG. FIG. 2 is a perspective view showing a snubber capacitor for a semiconductor module according to a second embodiment of the present invention.

As shown in FIG. 2, two resin molded capacitors 211 and 212 are provided.
1a and 212a have cylindrical terminals 22 and 23 and flat terminals 24, 25, 26 and 27 having a flat structure. Cylindrical terminal 2
Reference numerals 2 and 23 denote through terminals having a cylindrical structure similar to that of the first embodiment. The two capacitors 211 and 212 are connected in series by connecting the flat terminals 24 and 25 and the flat terminals 26 and 27 with two flat connectors 28 and 29, respectively.

Thus, the capacitor is divided into two parts,
By performing series connection outside the package for mounting, it is possible to adjust the pitch P between the cylindrical terminals 22 and 23 of the capacitor, and the applicability to various types of modules is expanded. At the same time, by connecting the capacitors 211 and 212 in series, 600 V
This has the effect of easily realizing a capacitor with a high withstand voltage exceeding that of the above, and widening the applicability from the manufacturing point of view.

A third embodiment of the present invention will be described with reference to FIG. FIG. 3A is a partial sectional view of a snubber capacitor for a semiconductor module according to a third embodiment of the present invention, and FIG. 3B is a side view thereof.

As shown in FIG. 3, the snubber capacitor 31 has a winding type vapor-deposited film capacitor element 34 in a resin-molded capacitor main body 31a and a through cylindrical terminal 32.
Is wound as a core, and metallicons are applied to both end surfaces to form metallikon portions 35 and 36. Then, the metallicon section 35 and the cylindrical terminal 32 and the metallicon section 36 and the flat plate terminal 37 are electrically connected to complete the capacitor.

As described above, since the core of the capacitor 31 is made of a metal conductor, the heat transfer from the inside of the capacitor 31 is increased, the heat radiation is improved, and the life characteristics of the capacitor 31 are improved. On the other hand, the self-healing characteristics (SH
It is known that this has a great influence on the properties of the film and the corona generation characteristics. However, in this embodiment, it is possible to wind the film firmly by forming the winding core with a metal having high rigidity. As a result, a corona generation voltage rise phenomenon occurs, and the effect of improving both the above characteristics can be obtained. This embodiment is applicable to the first or second embodiment.

[0019]

According to the snubber capacitor for a semiconductor module of the present invention, a cylindrical terminal having a cylindrical structure concentrically arranged with a semiconductor element electrode is provided in a state penetrating the capacitor body, and the capacitor is formed by a bolt penetrating the cylindrical terminal. Since the main body can be fixed to the semiconductor element electrode, the wiring inductance between the capacitor and the semiconductor element can be reduced. In other words, since the capacitor can be directly attached to the semiconductor element electrode, when applied to an inverter circuit, miniaturization can be realized, and at the same time, the wiring inductance of the snubber circuit can be reduced to the utmost limit, and a rise in switching voltage applied to the semiconductor element electrode is suppressed. As a result, the reliability of the inverter device can be improved. In addition, since the capacitor can be coaxially fixed to the semiconductor element electrode with the cylindrical terminal coaxially, the fixing strength of the capacitor can be improved.

According to the second aspect, the capacitor body has the cylindrical terminal and the flat plate terminal having a flat plate structure, and the flat terminals of the plurality of capacitor bodies are connected in series, so that the pitch between the cylindrical terminals of the plurality of capacitor bodies can be adjusted. As a result, the applicability to various types of semiconductor modules is expanded, and at the same time, a capacitor with a high withstand voltage can be easily realized by connecting the capacitors in series.

According to the third aspect of the present invention, since the cylindrical terminal is formed by the winding core of a wound-type vapor-deposited film capacitor element, the heat conductivity from the inside of the capacitor can be increased, the heat radiation can be improved, and the life characteristics of the capacitor can be improved. I do. In addition, when the core is made of a metal having high rigidity, a corona generation voltage rise phenomenon occurs, and the effect of improving the self-healing characteristics and the corona generation characteristics can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a snubber capacitor for a semiconductor module according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing a snubber capacitor for a semiconductor module according to a second embodiment of the present invention.

FIG. 3A is a partial sectional view of a snubber capacitor for a semiconductor module according to a third embodiment of the present invention, and FIG. 3B is a side view thereof.

FIG. 4 is a perspective view of a conventional snubber capacitor.

[Explanation of symbols]

 11, 211, 212, 31, 41 Capacitor 11a, 211a, 212a, 31a Capacitor body 12, 13, 22, 23, 32 Cylindrical terminal 14 Semiconductor module 15, 16, 17 Semiconductor module electrode terminal 18, 19 Connection wire with terminal 24, 25, 26, 27, 37, 42, 43 Flat terminal 34 Winding-type deposited film capacitor element 35, 36 Metallicon section

Claims (3)

[Claims] 1. A snubber capacitor for a semiconductor module connected to a semiconductor element electrode of a semiconductor module, wherein a cylindrical terminal having a cylindrical structure concentrically arranged with the semiconductor element electrode is provided in a state penetrating into a capacitor body. A snubber capacitor for a semiconductor module, wherein the capacitor body can be fixed to the semiconductor element electrode by a bolt penetrating a cylindrical terminal. 2. The snubber capacitor for a semiconductor module according to claim 1, wherein the capacitor body has a cylindrical terminal and a flat plate terminal, and the flat terminals of a plurality of capacitor bodies are connected in series. 3. The snubber capacitor for a semiconductor module according to claim 1, wherein the cylindrical terminal is formed by a winding core of a wound type vapor deposition film capacitor element.