JP4135295B2 - Cylindrical electrolytic capacitor and three-phase inverter device using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cylindrical electrolytic capacitor and a three-phase inverter circuit device using the same.
[0002]
[Prior art]
A conventional three-phase inverter circuit for driving and controlling a three-phase AC motor, for example, as described in Japanese Patent Application Laid-Open No. 2-294278, absorbs switching noise voltage emitted to positive and negative DC power supply lines. In general, one or more smoothing capacitors are connected in parallel between the positive and negative DC power supply terminals of the three-phase inverter circuit. As this type of smoothing capacitor, an electrolytic capacitor that can ensure a large capacity per volume is generally employed.
[0003]
Japanese Utility Model Laid-Open No. 4-45233 proposes that the shape of the electrolytic capacitor be a flat cylindrical shape.
[0004]
[Problems to be solved by the invention]
However, in the conventional three-phase inverter circuit device described above, if an ordinary cylindrical electrolytic capacitor is used as a smoothing capacitor, the required space for the smoothing capacitor increases and the size of the device increases. There is a problem that the capacitor capacity cannot be sufficiently secured in an application in which the restriction on the device accommodation space is large, and the switching noise voltage superimposed on the power supply line cannot be reduced.
[0005]
Further, when the three-phase inverter circuit is switched at a high speed, there is a problem that the AC power due to switching increases and the temperature rise due to resistance heat generation of the smoothing capacitor increases.
[0006]
There is a possibility of improving the heat dissipation of the smoothing capacitor by accommodating the flatly formed electrode roll in the flat cylindrical case, and reducing the idle space compared to the cylindrical capacitor, As a result, the average distance between the positive and negative terminals of the smoothing capacitor and the negative and positive foils increases, and the internal resistance of the capacitor increases accordingly, and the resistance loss increases the temperature of the capacitor. It has been found that there is a problem of further increase in the value.
[0007]
The present invention has been made in view of the above problems, and provides a cylindrical electrolytic capacitor capable of realizing a compact circuit device while suppressing an increase in the internal temperature rise of the smoothing capacitor, and a three-phase inverter device using the same. Its purpose is to do.
[0008]
[Means for Solving the Problems]
The present invention according to claim 1, which achieves the above object, comprises an electrode roll formed by sandwiching a negative foil and a positive foil between insulating spacers, and a case made of a cylindrical metal can that accommodates the electrode roll; A cylindrical electrolytic capacitor having an inner end portion separately joined to the two foils and a second end exposed at the end face of the case, and a positive electrode terminal and a negative electrode terminal, and the electrode roll and the case having a flat can shape In the above, a plurality of the positive terminals and the negative terminals are respectively arranged at predetermined intervals in a direction perpendicular to the thickness direction of the case.
[0009]
According to this configuration, since the cylindrical electrolytic capacitor is formed flat in both the case and the electrolytic capacitor, the heat transfer distance between the outer surface and the center of the case is reduced, so the heat dissipation is improves.
[0010]
However, in such a flat cylindrical capacitor, since the perimeter of each 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 increases, Electrode resistance increases and resistance loss increases.
[0011]
Thus, according to this configuration, a plurality of positive terminals and negative terminals are arranged at predetermined intervals in the width direction. As a result, the distance of the current path in the foil of the flat cylindrical capacitor can be dramatically shortened to reduce the electrode resistance, and the resistance loss and internal heat generation can be reduced, improving the efficiency and reducing the cooling burden. can do.
[0012]
The present invention according to claim 1 further includes a three-phase inverter circuit formed by mounting a plurality of semiconductor modules on a predetermined substrate, and a main surface of the semiconductor module being in contact with the semiconductor module. a plate-shaped cooling member that absorbs heat, is characterized in that arranged in a posture parallel to the substrate at the substrate opposite to the position and a said cylindrical electrolytic capacitor in contact with the other main surface of the cooling member .
[0013]
According to the second aspect of the present invention, in the three-phase inverter circuit device according to the first aspect of the present invention, the cylindrical length of the flat outer surface of the cylindrical electrolytic capacitor and the width perpendicular to the thickness direction are It is characterized by being set substantially equal to the full width of each semiconductor module in the width direction of the electrolytic capacitor.
[0014]
Here, “substantially equal” means a range of 80 to 120%.
[0015]
According to this configuration, the overall width of the device can be reduced, and 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 INVENTION
A preferred embodiment of a three-phase inverter device using a cylindrical electrolytic capacitor of the present invention will be described below with reference to the drawings.
[0017]
(Circuit configuration)
The circuit configuration of this three-phase inverter circuit device is shown in FIG.
[0018]
Reference numeral 1 denotes a battery, and reference numerals 2 to 7 denote semiconductor chips on which NMOSTs using the parasitic diodes as flywheel diodes are formed. The pair of semiconductor chips 2 and 3 constitutes a U-phase single-phase inverter circuit 100, and the pair of semiconductor chips 4 and 5 constitutes a V-phase single-phase inverter circuit 200. The pair constitutes a W-phase single-phase inverter circuit 300. Each single-phase inverter circuit 100, 200, 300 is individually modularized to form semiconductor modules 30, 40, 50.
[0019]
101 is a positive DC power supply terminal of the U-phase single-phase inverter circuit 100, 102 is a negative DC power supply terminal of the U-phase single-phase inverter circuit 100, and 103 is a U-phase single-phase inverter circuit 100. AC output terminal.
[0020]
201 is a positive DC power supply terminal of the V-phase single-phase inverter circuit 200, 202 is a negative DC power supply terminal of the V-phase single-phase inverter circuit 200, and 203 is a V-phase single-phase inverter circuit 200. AC output terminal.
[0021]
Reference numeral 301 is a positive DC power supply terminal of the W-phase single-phase inverter circuit 300, 302 is a negative DC power supply terminal of the W-phase single-phase inverter circuit 300, and 303 is a W-phase single-phase inverter circuit 300. AC output terminal.
[0022]
Each positive DC power supply terminal 101, 201, 301 is connected to the positive terminal of the battery 1 together with the positive terminal of the smoothing capacitor 8, and each negative DC power supply terminal 102, 202, 302 is connected to the battery together with the negative terminal of the smoothing capacitor 8. 1, each AC output terminal 103, 203, 303 supplies power to the three-phase AC motor 9.
[0023]
A controller 10 outputs a control voltage to the gate electrode of each IGBT and detects the temperature of each IGBT. The operation of the three-phase inverter circuit and the smoothing capacitor 8 is well known, and the description is omitted (semiconductor module configuration).
A semiconductor module 30 formed by modularizing the U-phase single-phase inverter circuit 100 is shown in FIG.
[0024]
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, and 11 and 12 are metal space transfer plates. Reference numerals 108 and 108 denote control electrode terminals of the semiconductor chips 2 and 3.
[0025]
The semiconductor chip 2 is soldered on the metal heat transfer plate 106 and the semiconductor chip 3 is soldered on the metal heat transfer plate 105. The metal spacers 11 and 12 are soldered on the semiconductor chips 2 and 3, and the metal spacers are soldered. A metal heat transfer plate 107 is soldered to the spacer 11, and a metal heat transfer plate 105 is soldered to the metal spacer 12. The metal spacers 11 and 12 ensure a thickness direction space for wire bonding between the control electrode terminal 108 of the semiconductor chips 2 and 3 and the control electrode surface (not shown) of the semiconductor chips 2 and 3. For the purpose.
[0026]
Finally, this single-phase inverter circuit 100 is sealed with a resin mold in a state where the outer main surfaces of the metal heat transfer plates 105 to 107 are exposed and the terminals 101 to 103 are projected. -It is said that
[0027]
Since the semiconductor modules 40 and 50 have the same structure as the semiconductor module 30, the description thereof is omitted.
[0028]
(Configuration of smoothing capacitor 8)
The smoothing capacitor 8 is formed in a flat cylindrical shape as shown in FIG.
[0029]
Reference numeral 80 denotes a flat cylindrical one-end opening aluminum alloy case formed by deep drawing, and accommodates a flat columnar electrode roll (not shown) inside. The electrode roll is formed by flatly winding two porous spacers impregnated with an electrolytic solution and a negative electrode foil and a positive electrode foil separated from each other by these porous spacers. The electrode roll itself is well known and will not be described in detail.
[0030]
The opening of the case 80 is closed by a cover plate 81. The lid plate 81 is made of an insulating resin plate and has four holes. Two positive terminals 82 and two negative terminals 83 are penetrated and fixed in these holes. The positive terminal 82 and the negative terminal 83 are arranged at a predetermined interval in the left-right direction in FIG.
[0031]
The positive electrode terminal 82 and the negative electrode terminal 83 are welded with one end of a number of metal leads in a case 80, and each lead extended from the positive electrode terminal 82 is wound around an electrode roll. Each lead which is welded to the surface of the positive electrode foil of the electrode roll before taking up and extends from the negative electrode terminal 83 is extended to the surface of the negative electrode foil before winding up the electrode roll.
[0032]
A structure for fixing the opening edge 80a of the case 80 to the peripheral edge of the cover plate 81 will be described below with reference to FIG.
[0033]
In this embodiment, a metal ring 85 having a U-shaped cross section is inserted to cover the peripheral edge of the cover plate 81, and the inner peripheral surface of the opening edge 80 a of the case 80 is the metal ring 85. It is welded to the outer peripheral surface. In this way, it is possible to withstand a significant increase in internal pressure as compared with the conventional lid plate fixing method by caulking.
[0034]
If the lid plate is a metal plate, the lid 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 lid plate 81. Therefore, it is necessary to fix the terminals 82 and 83 to the cover plate 81 through an electrically insulating resin ring.
[0035]
(Overall equipment configuration)
The overall configuration of the three-phase inverter circuit device of this embodiment will be described below with reference to FIG. 3 showing a front view thereof.
[0036]
Reference numeral 60 denotes a refrigerant tube forming a cooling member in the present invention.
[0037]
The refrigerant tube 60 is manufactured by cutting a plate material formed by drawing or extrusion molding an aluminum alloy into a required length. The refrigerant tube 60 has a plurality of through passages that are partitioned from each other by a partition wall in the width direction and extend in the longitudinal direction. Both ends of the refrigerant tube 60 are joined to an inlet-side header 6a and an outlet-side header 6b, and are connected to an external refrigeration cycle apparatus (not shown) through these headers to constitute the evaporator.
[0038]
The refrigerant tube 60 is flat and easily plastically deformed in the thickness direction, and is bent in a zigzag manner. The refrigerant tube 60 includes three flat portions 61 to 63 that are flat and parallel to each other and face each other, a curved portion 64 between the flat portions 61 and 62, and a curved portion 65 between the flat portions 62 and 63. Have.
[0039]
The flat portions 61, 62 of the refrigerant tube 60 sandwich the semiconductor modules 30, 40, 50 while ensuring electrical insulation from the refrigerant tube 60 by an electric insulating spacer (not shown). The semiconductor modules 30, 40, 50 are arranged at regular intervals in the flow path direction of the refrigerant tube 60. The flat portion 61 is in close contact with the outer main surface of the metal heat transfer plate 105 of the semiconductor module 30, and 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. The same applies to the other semiconductor modules 40 and 50.
[0040]
The flat portions 62 and 63 and the curved portion 65 of the refrigerant tube 60 are in close contact with two flat surfaces of the outer peripheral surface of the smoothing capacitor 81 and one semi-cylindrical curved surface.
[0041]
Heat sinks 91, 92, 93 made of aluminum alloy blocks are fixed to the flat outer surface of the flat portion 61 of the refrigerant tube 60 on the side opposite to the semiconductor module by bolts 94. , 93 is joined to a control circuit board 95 for exchanging signals with the control electrode terminals of the semiconductor modules 30, 40, 50. The heat sinks 91, 92, 93 are arranged at positions facing the semiconductor modules 30, 40, 50 across the flat portion 61 of the refrigerant tube 60, so that the semiconductor modules 30, 40, 50 are temporarily large. It is designed to absorb heat generation well.
[0042]
(Example effect)
According to this configuration, the semiconductor modules 30, 40, 50 of the three-phase inverter circuit and the smoothing capacitor 8 can be cooled by the common cooling member, and they are stacked in the thickness direction of the smoothing capacitor, so that the apparatus Can be made compact, and the required space can be reduced. In addition, when the three-phase inverter circuit generates a large amount of heat temporarily, the smoothing capacitor can function as a heat sink via the cooling member, thus preventing the transient temperature rise of the three-phase inverter circuit. can do.
[0043]
According to the present embodiment, the width of the flat outer surface of the smoothing capacitor 8 (the dimension in the left-right direction shown in FIG. 3) is set to be approximately equal to the total width L of the three semiconductor modules 30, 40, 50. Are opposed to each other with the refrigerant tube 60 interposed therebetween, so that the thermal resistance in the heat transfer between the smoothing capacitor 8 and the semiconductor modules 30, 40, 50 can be reduced. It can function well as 50 heat sinks.
[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 diagram of a semiconductor module of the apparatus shown in FIG.
FIG. 3 is a front view of the apparatus shown in FIG. 1;
4 is a partial cross-sectional view of the smoothing capacitor shown in FIG. 3;
[Explanation of symbols]
8: Smoothing capacitor 30: Semiconductor module 40: Semiconductor module 50: Semiconductor module 60: Refrigerant tube

Claims (2)

An electrode roll formed by sandwiching a negative electrode foil and a positive electrode foil with insulating spacers, a case made of a cylindrical metal can that accommodates the electrode roll, and an inner end portion individually joined to the two foils wherein the end portion Ke - a positive and negative terminals are exposed on the end surface of the scan, the electrode roll and the case will have a flat cans shape, the positive and negative terminals before speechless - scan in the thickness direction a cylindrical capacitor that will be more disposed respectively at a predetermined distance from each other in the perpendicular direction,
A three-phase inverter circuit in which a plurality of semiconductor modules are mounted on a predetermined substrate;
A plate-like cooling member whose one main surface is in contact with the semiconductor module and absorbs heat of the semiconductor module;
The three-phase inverter circuit device, wherein the cylindrical electrolytic capacitor is disposed in a posture parallel to the substrate at a position facing the substrate, and is in contact with the other main surface of the cooling member. In the three-phase inverter circuit device according to claim 1 ,
The dimensions of the width of the flat outer surface of the cylindrical electrolytic capacitor perpendicular to the cylinder length direction and the thickness direction are set to be approximately equal to the total width of each semiconductor module in the width direction of the cylindrical electrolytic capacitor. A three-phase inverter circuit device.

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