JP2001307953A - Cylindrical electrolytic capacitor and three-phase inverter using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cylindrical electrolytic capacitor and a three-phase inverter using the same by which the rising in temperature within a smoothing capacitor can be suppressed and a circuit be made compact in size. SOLUTION: A cylindrical electrolytic capacitor 8 as well as a case and an electrolytic capacitor is made flat, so that a heat conducting distance between the outer surface and center of the case becomes small and its heat radiation property is improved. Since the capacitor 8 is provided with a plurality of positive electrode terminals 82 and negative electrode terminals 83, an increase in electrode resistance can be avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a cylindrical electrolytic capacitor and a three-phase inverter circuit device using the same.

[0002]

2. Description of the Related Art A conventional three-phase inverter circuit for driving and controlling a three-phase AC motor is disclosed, for example, in Japanese Patent Laid-Open No. 2-294278.
In order to absorb the switching noise voltage released to the positive and negative DC power supply lines, one or a plurality of smoothing capacitors may be connected in parallel between the positive and negative DC power supply terminals of the three-phase inverter circuit as described in Japanese Patent Application Publication No. General.
As this type of smoothing capacitor, it is common to employ an electrolytic capacitor capable of securing a large capacity per volume.

[0003] Japanese Utility Model Laid-Open No. 4-45233 proposes that the shape of an electrolytic capacitor be a flat cylindrical shape.

[0004]

However, in the above-described conventional three-phase inverter circuit device, if a normal cylindrical electrolytic capacitor is used as the smoothing capacitor, the required space for the smoothing capacitor becomes large, and the device size becomes large. Due to the increase in size, there is a problem that the capacity of the capacitor cannot be sufficiently secured in an application where the space for accommodating the circuit device is large, such as for a vehicle, and the switching noise voltage superimposed on the power supply line cannot be reduced.

Further, when the three-phase inverter circuit is switched at a high speed, there is a problem that the AC power due to the switching increases, and the temperature rise due to the resistance heating of the smoothing capacitor increases.

By accommodating a flat electrode roll in a flat cylindrical case, the heat dissipation of the smoothing capacitor can be improved, and the idle space can be reduced as compared with the cylindrical capacitor. However, if you do this,
The average distance between the positive electrode terminal and the negative electrode terminal of the smoothing capacitor and the negative electrode foil and the positive electrode foil increases, and the internal resistance of the capacitor increases by that much, and the temperature rise of the capacitor further increases due to the resistance loss. It turns out that a problem arises.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a cylindrical electrolytic capacitor capable of realizing a compact circuit device while suppressing an increase in the internal temperature of a smoothing capacitor, and a three-phase inverter using the same. Its purpose is to provide a device.

[0008]

According to a first aspect of the present invention, there is provided a cylindrical electrolytic capacitor for accommodating an electrode roll formed by winding a negative electrode foil and a positive electrode foil with an insulating spacer interposed therebetween, and the electrode roll. A case made of a cylindrical metal can, and a positive electrode terminal and a negative electrode terminal whose inner ends are individually bonded to the two foils and the other ends of which are exposed at the end surfaces of the case. The case is a cylindrical electrolytic capacitor having a flat can shape, wherein a plurality of the positive electrode terminals and a plurality of the negative electrode terminals are arranged at predetermined intervals from each other in a direction perpendicular to the thickness direction of the case. I have.

According to this configuration, the cylindrical electrolytic capacitor is
Since both the case and the electrolytic capacitor are formed flat,
The heat dissipation is improved because the heat transfer distance between the outer surface and the center of the case is reduced.

However, in such a flat cylindrical capacitor, since the perimeter per one turn of the negative electrode foil and the positive electrode foil increases, the distance of the current path in the foil between the positive electrode terminal and the negative electrode terminal is reduced. Increase, the electrode resistance increases, and the resistance loss increases.

Therefore, according to this configuration, a plurality of positive terminals and a plurality of negative terminals are disposed at predetermined intervals in the width direction. As a result, the distance of the current path in the above-mentioned foil of the flat cylindrical capacitor can be remarkably shortened to reduce the electrode resistance, thereby reducing the resistance loss and internal heat generation, improving the efficiency and reducing the cooling burden. can do.

According to a second aspect of the present invention, there is provided a three-phase inverter circuit device using the cylindrical electrolytic capacitor according to the first aspect, wherein a plurality of semiconductor modules are mounted on a predetermined substrate. A plate-shaped cooling member having one main surface in contact with the semiconductor module and absorbing heat of the semiconductor module; and a cooling member arranged at a position facing the substrate in a posture parallel to the substrate. A cylindrical electrolytic capacitor according to claim 1, which is in contact with the other main surface of the member.

According to a third aspect of the present invention, in the three-phase inverter circuit device according to the second aspect, the width of the flat outer surface of the cylindrical electrolytic capacitor in a direction perpendicular to a length direction and a thickness direction of the cylindrical electrolytic capacitor is further defined. The width is set substantially equal to the entire width of each semiconductor module in the width direction of the cylindrical electrolytic capacitor.

Note that the term "substantially equal" as used herein means 80 to
It means the range of 120%.

According to this configuration, the overall width of the device can be reduced,
Further, the distance between each semiconductor module and the smoothing capacitor can be reduced to reduce the heat transfer resistance of the smoothing capacitor during the heat sink.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a three-phase inverter device using a cylindrical electrolytic capacitor according to the present invention will be described below with reference to the drawings.

(Circuit Configuration) FIG. 1 shows a circuit configuration of the three-phase inverter circuit device.

1 is a battery, and 2 to 7 are NMs each using a parasitic diode as a flywheel diode.
This is a semiconductor chip on which OST is formed. The pair of semiconductor chips 2 and 3 constitutes a U-phase single-phase inverter circuit 100, the pair of semiconductor chips 4 and 5 constitutes a V-phase single-phase inverter circuit 200, and the semiconductor chips 6 and 7 The pair constitutes a W-phase single-phase inverter circuit 300. Each of the single-phase inverter circuits 100, 200, 300 is individually modularized, and the semiconductor modules 30, 40, 50
It has become.

Reference numeral 101 denotes a U-phase single-phase inverter circuit 100.
Is a negative DC power supply terminal of the U-phase single-phase inverter circuit 100; and 103 is an AC output terminal of the U-phase single-phase inverter circuit 100.

Reference numeral 201 denotes a V-phase single-phase inverter circuit 200.
Is a negative DC power supply terminal of the V-phase single-phase inverter circuit 200; and 203 is an AC output terminal of the V-phase single-phase inverter circuit 200.

Reference numeral 301 denotes a W-phase single-phase inverter circuit 300.
Is a negative DC power supply terminal of the W-phase single-phase inverter circuit 300; and 303 is an AC output terminal of the W-phase single-phase inverter circuit 300.

Each positive DC power supply terminal 101, 201, 30
1 is connected to the positive terminal of the battery 1 together with the positive terminal of the smoothing capacitor 8, and each of the negative DC power terminals 102, 20
Reference numerals 2 and 302 are connected to the negative terminal of the battery 1 together with the negative terminal of the smoothing capacitor 8, and the AC output terminals 103 and
Numerals 03 and 303 supply power to the three-phase AC motor 9.

A controller 10 outputs a control voltage to the gate electrode of each IGBT and detects the temperature of each IGBT. The operation itself of the three-phase inverter circuit and the smoothing capacitor 8 is well known, and the description is omitted (semiconductor module configuration) U-phase single-phase inverter circuit 1
FIG. 2 shows a semiconductor module 30 obtained by modularizing 00.

105 is a metal heat transfer plate having an AC output terminal 103; 106 is a metal heat transfer plate having a positive DC power supply terminal 101; 107 is a metal heat transfer plate having a negative DC power supply terminal 102; A metal spacer 108 is a control electrode terminal of the semiconductor chips 2 and 3.

The semiconductor chip 2 is placed on the metal heat transfer plate 106.
The semiconductor chip 3 is soldered on the metal heat transfer plate 105, and the metal spacers 11 and
A metal heat transfer plate 107 is soldered to the metal spacer 11, and a metal heat transfer plate 105 is soldered to the metal spacer 12. The metal spacers 11 and 12 secure a space in the thickness direction for wire bonding between the control electrode terminals 108 of the semiconductor chips 2 and 3 and control electrode surfaces (not shown) of the semiconductor chips 2 and 3. It is interposed for.

Finally, the single-phase inverter circuit 100
Is sealed with resin mold so that the outer main surfaces of the metal heat transfer plates 105 to 107 are exposed and the terminals 101 to 103 are protruded to form a semiconductor module.

The semiconductor modules 40 and 50 have the same structure as the semiconductor module 30 and will not be described.

(Configuration of Smoothing Capacitor 8) The smoothing capacitor 8 is formed in a flat cylindrical shape as shown in FIG.

Reference numeral 80 is a flat cylindrical aluminum alloy case formed by deep drawing and having an opening at one end, and accommodates a flat columnar electrode roll (not shown) therein. The electrode roll comprises two porous spacers impregnated with an electrolyte,
The negative electrode foil and the positive electrode foil separated from each other by the porous spacers are formed by flat winding. The electrode roll itself is well known, and a detailed description is omitted.

The opening of the case 80 is closed by a lid plate 81. The cover plate 81 is made of an insulating resin plate and has four holes. Two positive terminals 82 and two negative terminals 83 penetrate and are fixed in these holes. The positive terminal 82 and the negative terminal 83 are arranged at predetermined intervals in the left-right direction in FIG.

The positive terminal 82 and the negative terminal 83 have a case.
One end of a large number of metal leads is welded in the lead 80, and each lead extending from the positive electrode terminal 82 is placed on the surface of the positive electrode foil of the electrode roll before winding the electrode roll. Each lead which is welded and extended from the negative electrode terminal 83 is extended on the surface of the negative electrode foil before winding the electrode roll.

The structure for fixing the opening edge portion 80a of the case 80 to the peripheral edge portion of the cover plate 81 will be described below with reference to FIG.

In this embodiment, a metal ring 85 having a U-shaped cross section is formed by insert molding so as to cover the peripheral edge of the cover plate 81, and the inner peripheral surface of the opening edge 80a of the case 80 is made of metal. It is welded to the outer peripheral surface of the ring 85. In this case, the internal pressure can be significantly increased as compared with the conventional method of fixing the cover plate by swaging.

If the cover plate is a metal plate, the cover plate 81 and the case 80 can be firmly joined by laser welding or the like, but the terminals 82 and 83 are electrically insulated from the cover plate 81. Therefore, it is necessary to fix the terminals 82 and 83 to the cover plate 81 via an electrically insulating resin ring.

(Overall Device Configuration) The overall configuration of the three-phase inverter circuit device of this embodiment will be described below with reference to FIG.

Numeral 60 is a refrigerant tube forming a cooling member according to the present invention.

The refrigerant tube 60 is made by cutting a plate formed by drawing or extruding an aluminum alloy into a required length. Refrigerant tube
The bush 60 has a plurality of through flow paths that are partitioned from each other by partition walls in the width direction and extend in the longitudinal direction.
Both ends of the refrigerant tube 60 are joined to a header 6a on the entrance side and a header 6b on the exit side, and connected to an external refrigeration cycle device (not shown) through these headers to constitute an evaporator.

The refrigerant tube 60 has a characteristic of being flat and easily plastically deformable in the thickness direction, and is bent in a zigzag shape. The refrigerant tube 60 includes three flat portions 61 to 63 which are flat, parallel to each other and face each other, a flat portion 61,
A curved portion 64 between the flat portions 62 and 63 and a curved portion 65 between the flat portions 62 and 63 are provided.

The flat portions 61 and 62 of the refrigerant tube 60 are
A refrigerant tube 60 is formed by an electrically insulating spacer (not shown).
Semiconductor modules 30, 4 while ensuring electrical insulation from
0, 50 are sandwiched between the semiconductor modules 30, 4
Numerals 0 and 50 are arranged at regular intervals in the flow direction of the refrigerant tube 60. The flat part 61 is a semiconductor module 3
The flat portion 62 is in close contact with the outer main surfaces of the metal heat transfer plates 106 and 107 of the semiconductor module 30. Other semiconductor modules 40, 50
The same is true for

The flat portions 62 and 63 and the curved portion 65 of the refrigerant tube 60 are in close contact with two flat surfaces and one semicylindrical curved surface of the outer peripheral surface of the smoothing condenser 81.

Heat sinks 91, 92 and 93 made of an aluminum alloy block are fixed to bolts 94 on the flat outer surface of the flat portion 61 of the refrigerant tube 60 on the side opposite to the semiconductor module. Control circuit boards 95 for transmitting and receiving signals to and from control electrode terminals of the semiconductor modules 30, 40, and 50 are joined to the components 91, 92, and 93, respectively.
The heat sinks 91, 92, and 93 are provided between the semiconductor modules 30, 40, and 50 with the flat portion 61 of the refrigerant tube 60 interposed therebetween.
Is disposed at a position facing the semiconductor module 30,
40, 50 temporary large heat generation is absorbed well.

(Effects of Embodiment) According to this configuration, the semiconductor modules 30, 40 and 50 of the three-phase inverter circuit and the smoothing capacitor 8 can be cooled by a common cooling member, and they can be cooled by the smoothing capacitor. Since the layers are stacked in the thickness direction, the apparatus can be made compact, and the required space can be reduced. Furthermore, when the three-phase inverter circuit temporarily generates a large amount of heat, the smoothing capacitor can function as a heat sink via the cooling member, thereby suppressing the transient temperature rise of the three-phase inverter circuit. can do.

According to this embodiment, the width of the flat outer surface of the smoothing capacitor 8 (the dimension in the horizontal direction shown in FIG. 3)
Is set to be substantially equal to the total width L of the three semiconductor modules 30, 40, and 50, and they are opposed to each other across the refrigerant tube 60. Therefore, the smoothing condenser 8 and the semiconductor modules 30, 40, 50 Can be reduced, and the smoothing capacitor 8 can function well as a heat sink for the semiconductor modules 30, 40, and 50.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a three-phase inverter circuit device using a cylindrical electrolytic capacitor of the present invention.

FIG. 2 is an assembly view of a semiconductor module of the device shown in FIG.

FIG. 3 is a front view of the device shown in FIG. 1;

FIG. 4 is a partial sectional view of the smoothing capacitor shown in FIG.

[Explanation of symbols]

 8: Smoothing capacitor 30: Semiconductor module 40: Semiconductor module 50: Semiconductor module 60: Refrigerant tube

Claims (3)

[Claims] 1. An electrode roll formed by winding a negative electrode foil and a positive electrode foil sandwiched between insulating spacers, a case made of a cylindrical metal can for accommodating the electrode roll, and an inner end portion of each of the two foils. A positive electrode terminal and a negative electrode terminal, the other end of which is exposed to the end face of the case, wherein the electrode roll and the case are cylindrical electrolytic capacitors having a flat can shape, wherein the positive electrode terminal and the negative electrode terminal are A plurality of cylindrical capacitors are provided at predetermined intervals in a direction perpendicular to the thickness direction of the case. 2. A three-phase inverter circuit comprising a plurality of semiconductor modules mounted on a predetermined substrate, and a plate having one main surface in contact with the semiconductor modules and absorbing heat of the semiconductor modules. A cylindrical cooling capacitor according to claim 1, which is disposed in a position facing the substrate in a position parallel to the substrate and is in contact with the other main surface of the cooling member. Three-phase inverter circuit device. 3. The three-phase inverter circuit device according to claim 2, wherein a dimension of a flat outer surface of the cylindrical electrolytic capacitor in a width direction perpendicular to a cylinder length direction and a thickness direction is equal to the width of the cylindrical electrolytic capacitor. 3. A three-phase inverter circuit device, wherein the three-phase inverter circuit device is set to be substantially equal to a total width of each of the semiconductor modules in a width direction.