JP2595229Y2 - Low inductance capacitor - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-voltage DC capacitor having a large capacity used for a filter or the like, and more particularly to an improvement of a low-inductance capacitor.

[0002]

2. Description of the Related Art Generally, in a DC capacitor, as shown in FIGS. 6 and 8, a composite dielectric 23 formed by a combination of a capacitor paper 23a and an organic film 23b is provided with two metal electrode foils 21 and 22. Intervening in between,
The capacitor element 24 is formed by winding. In such an element 24, as a means for extracting the electrode foils 21 and 22 to the outside of the element 24, lead foils LA and LB are attached to the electrode foil.
Are electrically connected by performing operations such as welding and pressure welding. Such lead foils LA and LB are:
As shown in FIG. 8, the first aluminum electrode 21
The lead foil LA of the second
Are disposed in the vicinity of the center of the electrode foil in the longitudinal direction, and are pulled out from one end face of the element.

As a DC capacitor using such an element, for example, as shown in FIGS. 7 and 9, a body 25 formed by connecting a plurality of elements to obtain a predetermined capacity is a tin case. 26, and lead foils LA, LB
Is connected to the conductor of the insulating bushing 28 provided on the upper lid 27 via the lead wire 29, and then the insulating oil is sealed in the case, and thereafter, the exterior of the case is closed or the like is sealed. Filter DC capacitors exist.

[0004]

In recent power supply circuits, the switching frequency has been increased, and the residual inductance of the capacitor, which has not been a problem in conventional circuits, has become a problem. That is, if the residual inductance is large, there is a problem that the loss is large in the circuit configuration and the efficiency is reduced. For this reason, the inductance must be smaller than in the conventional case, and this value is required to be about 1/2 of the conventional case. In the prior art capacitor, the residual inductance generally depends on the size of the case but is in the range of 0.1 to 0.5.
It is about 5 μH.

However, in the prior art, it is difficult to reduce the residual inductance for the following reasons. That is, as shown in FIG.
A and LB are pulled out from one end face of the wound element body 25, and the element bodies are stored in a tin case 26. At this time, in order to connect the lead foil to the conductor of the insulating bushing 28 disposed at two places near and far from the end face of the element body 25 via the lead wire 29, one lead wire 29a is compared with one lead wire 29a. The distance to the bushing conductor is considerably long. In such a state, the inductance of the lead wire 29b becomes a large value.

In addition, since the two lead foils LA and LB are drawn out from one end face of the element body 25, the current flows in one direction, and therefore, a structure in which an inductance is generated without a current canceling structure. Become. In order to solve this problem, a conventional technique has been proposed in which one lead foil is drawn out in the opposite direction to the drawing direction of the other lead foil so that the lead foil is drawn out from both end faces of the element body. However, even in that case, the current becomes a one-way loop current, and it cannot be expected that the inductance is low.

Further, a case 26 in which the element body 25 is stored
Is made of tin, the case acts as a magnetic material, and is more susceptible to induction electromagnetic action by high-frequency ripple current. Therefore, it is difficult to reduce the inductance.

The present invention has been proposed to solve the above-mentioned problems of the prior art. The object of the present invention is to improve the structure of a capacitor element so that the inductance value is reduced. It is to provide an inductance capacitor.

[0009]

According to the present invention, a dielectric containing a capacitor paper or an organic film is interposed between two metal electrode foils, and a plurality of lead foils are connected to each metal electrode foil and wound. A low-inductance capacitor in which at least one element is housed in a case, of the two metal electrode foils, at least one of each of the two metal electrode foils is wound in the opposite direction from the winding start side and the winding end side. The lead foil is pulled out, and at the other metal electrode foil, at least one lead foil is pulled out from the winding start side and the winding end side in a direction opposite to the one metal electrode foil, and pulled out from the one metal electrode foil. The lead foil is connected to a power supply circuit, and the lead foil extracted from the other metal electrode foil is connected to a case made of non-magnetic metal. The one in which the features.

[0010]

The operation of the present invention having the above configuration is as follows. That is, the respective lead foils connected to the one and the other metal electrode foils are pulled out from the respective end faces of the element, that is, when formed as an element, the anode and the cathode form a pair from both end faces, respectively. Then, the structure is drawn out, and the wiring becomes symmetrical. In this state, when the lead foil drawn from one metal electrode foil is connected to the power supply circuit, and the lead foil drawn from the other metal electrode foil is connected to the case made of non-magnetic metal, a current of the same magnitude is obtained. Each flows in the opposite direction and passes through the element, so that the respective magnetic fields cancel each other and the inductance is reduced. Further, since the lead foil is drawn out from both end faces of the element, by providing the conductor of the power supply circuit at two places of the case close to each end face of the element, the connection to the power supply can be made short distance, respectively. It can be an inductance.

Further, since the case is made of a non-magnetic metal, the electromagnetic action of the entire element in the case is reduced, and the entire case acts as a grounding side to provide a shielding effect and reduce the residual inductance. be able to.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a low inductance capacitor according to the present invention will be specifically described below with reference to the drawings. FIG. 1 is a perspective view showing a capacitor element which is a component of the low inductance capacitor of the present embodiment, FIG. 2 shows a body obtained by connecting a plurality of capacitor elements of FIG. 1 in parallel, and FIG. X is a side view, (b) is a front view, (c) is a side view on the end face Y side, FIG. 3 shows the configuration of FIG. 1, (a) is a plan view showing a state before winding, (b) 4) is a side view, FIG. 4 is a cross-sectional view showing a state where the element body of FIG. 2 is housed in a case made of brass, and FIG. 5 is an explanatory view showing a connection state inside the case of FIG.

In this embodiment, as shown in FIGS. 1 and 3, two aluminum electrode foils 1 and 2 each having a width of 90 mm and a thickness of 8 μm are used as electrodes, and a film-like film (described later) is interposed between the aluminum electrode foils. Is wound with a winding core of 43 mm to form a capacitor element 4 having a total capacitance of 101 turns and a capacitance of one element of 3.0 μF. The dielectric 3 is
A capacitor paper 3b having a width of 100 mm and a thickness of 10 μm is interposed between two organic films 3 a having a width of 100 mm and a thickness of 9 μm. During the winding process of the capacitor element 4 formed as described above, the 25th and 75th winding times
As shown in FIG. 3, lead foils A and B for extracting electrodes are inserted in contact with the aluminum electrode foils 1 and 2 and are electrically connected. When the number of turns is 25, the lead foil A ₁ is applied to the first electrode foil 1 from one end face X of the element, and the other end face Y
And insert the lead foil B ₁ into the second electrode foil 2 from
One end of each of the lead foils A ₁ and B ₁ is disposed so as to be drawn out from each of the end faces X and Y. At the time of the 75th winding, each lead foil is inserted from the end face opposite to the last time. That is, the lead foil A ₂ is inserted into the first electrode foil 1 from the end face Y, and the lead foil B ₂ is inserted into the second electrode foil 2 from the end face X of the electrode foil in the same manner as described above. Therefore, the lead foils A ₁ and B ₂ extend from one end face Y from the end face X of the element.
Has a structure in which the lead foils B ₁ and A ₂ are drawn out.

The capacitor element 4 configured as described above
Are connected in parallel as shown in FIG.
The element body 5 is formed as a 3 μF element body, and the element body 5 is wrapped with insulating paper and stored in a brass case 6 having an upper lid 7. At this time, the same type of lead foil (A ₁ , A ₁ ,...; A ₂ , A ₂ ,... B ₁ , B ₁ ,.
..; B ₂ , B ₂ ,...) Are overlapped and connected to each other to form one lead electrode A ₁₁ , A ₁₂ , B ₁₁ , B ₁₂ . Further, the lead electrodes A ₁₁ and A ₁₂ are connected to the center conductors of the insulating bushings 8 and 8 provided on the upper lid 7 via the lead wires 9 with insulating sleeves, respectively, at the shortest distance.
The lead electrodes B ₁₁ and B ₁₂ are connected to the upper lid 7 via the lead wires 10 respectively. The case 6 has a width of 115 mm, a depth of 93 mm, and a height of 230 m.
m and is configured as a container of the ground potential.
Further, the insulating bushings 8 provided on the upper lid 7 are provided at two places close to the respective end faces X and Y of the element body 5.

As shown in FIG. 4, after the element body 5 is housed in the case 6, a certain amount of high-quality electric insulating oil 12 necessary for impregnation of the element body 5 is filled therein. A fixed plate 11 is disposed on the upper part of the body, and the element body is fixed and sealed, thereby completing the capacitor.

[0016] In thus formed present invention of a capacitor, the power supply circuit is connected to the center conductor of the lead electrodes A _11, A ₁₂ of the connected insulated bushing 8, 8 applies a voltage rating. As a result, as shown in FIG. 5, current flows from the lead electrodes A ₁₁ and A ₁₂ to the lead electrode B on the ground side.
_11, flows to _{B 12.} These currents are equal in magnitude, and as shown in FIG. 4, the leads 9 and 10 with the insulating sleeve come close to each other, and the currents flow in opposite directions, and the respective magnetic fields due to the currents cancel each other. . Further, in FIG. 3, the current flows from the lead electrodes A ₁ to the lead electrodes B ₁ and B ₂ on the ground side lead electrode A
It flows from ₂ to lead electrodes _{B 2} and _{B 1.} Here, the current flowing from the current and the lead electrode A ₂ flowing from the lead electrodes A ₁ to B ₂ to B ₁ represents, with equal size, results in each of which passes through the element flows in the reverse direction, the current Cancel each other's magnetic field. This is the same for the entire element body 5, and the inductance can be reduced.

Further, since the case 6 is made of brass and thus becomes a non-magnetic material, the electromagnetic action of the whole element body 5 can be reduced even when the magnetic field is not completely canceled out.
Further, since the entire case 6 acts as the ground side, it has a shielding effect.

Furthermore, since the lead electrodes A ₁₁ and A ₁₂ are connected to the power supply circuit as anodes and the lead electrodes B ₁₁ and B ₁₂ are on the ground side as cathodes, the anode and the cathode are separated from both end surfaces X and Y of the element 4. The structures are drawn out in pairs, and the wiring is symmetrical. Moreover, the lead electrodes A ₁₁ , A
Insulating bushing 8,8 for connecting ₁₂ to the power circuit
However, since they are close to the respective end faces X and Y of the element body 5, they can be connected with short lead wires. With such a structure, the inductance can be reduced.

Subsequently, with respect to the low inductance capacitor (embodiment) of the embodiment formed as described above,
The inductance value was actually measured together with a conventional capacitor (conventional product) formed in the same rated capacity (33 μm) and the same case size. The result is
The results are shown in Table 1 below.

[0020]

[Table 1]

As shown in this table, the inductance of the capacitor of the present embodiment was less than half the value of the conventional product.

It should be noted that the present invention is not limited to the above embodiment, and the case is not limited to the case made of brass, but may be made of another non-magnetic metal. In addition, the same excellent operational effects as those of the above embodiment can be obtained.

Further, the present invention is not limited with respect to the rating and case size of the capacitor of the above-described embodiment, and the components of the element, and is applicable to various types of DC capacitors. The same excellent operational effects as those of the above embodiment can be obtained. That is, the present invention provides a capacitor in which a dielectric is interposed between two metal electrode foils and one or more elements formed by connecting and winding a plurality of lead foils to each metal electrode foil are housed in a case. In one of the two metal electrode foils, one of the two metal electrode foils has a width of one from the winding start side and one from the winding end side.
The lead foil is pulled out in the opposite direction by each book, and in the other metal electrode foil, the lead foil is pulled out one by one in the opposite direction to the one metal electrode foil from the winding start side and the winding end side,
The lead foil drawn from the one metal electrode foil is connected to a power supply circuit, and the lead foil drawn from the other metal electrode foil is connected to a case made of a non-magnetic metal. Therefore, as long as it has this feature, various other specific configurations can be freely selected, and irrespective of these other configurations, the same excellent operational effects as those of the above-described embodiment can be obtained. It is.

[0024]

As described above, according to the present invention, by improving the structure of the capacitor element, it is possible to provide a low-inductance capacitor capable of reducing the inductance value. Therefore, it is possible to improve the efficiency of the power supply circuit with a simple configuration and to provide a low-inductance capacitor that can be downsized.

[Brief description of the drawings]

FIG. 1 is a perspective view showing one embodiment of a low inductance capacitor according to the present invention, particularly showing a capacitor element as a constituent member.

2A and 2B show an element body formed by connecting a plurality of capacitor elements of FIG. 1 in parallel, wherein FIG. 2A is a side view on an end face X side, FIG. 2B is a front view, and FIG. 2C is a side view on an end face Y side. .

FIGS. 3A and 3B show the configuration of FIG. 1, wherein FIG. 3A is a plan view showing a state before winding, and FIG.

FIG. 4 is a sectional view showing a state where the element body of FIG. 2 is housed in a case made of brass.

FIG. 5 is an explanatory diagram showing a connection state inside the case of FIG. 4;

FIG. 6 is a perspective view showing a conventional capacitor element.

FIG. 7 is a side view of a lead foil connection side showing a body made of the capacitor element of FIG. 6;

8A and 8B show the configuration of FIG. 6, wherein FIG. 8A is a plan view showing a state before winding, and FIG.

FIG. 9 is a sectional view showing a state where the element body of FIG. 7 is housed in a tin case.

[Explanation of symbols]

1,2,21,22 ... Aluminum electrode foil 3,23 ... Dielectric 4,24 ... Capacitor element 5,25 ... Element body 6 ... Brass case 7,27 ... Top lid 8,28 ... Insulating bushing 9 ... Lead with insulating sleeve line 10 ... lead wire 11 ... fixing plate 12 ... electrical insulating oil 26 ... tinplate case 29 ... lead wire _{A 1, A 2, B 1} , B 2, LA, LB ... lead foil _{A 11, A 12, B 11} , B ₁₂ … Lead electrode

Claims (1)

(57) [Scope of request for utility model registration] 1. A device comprising at least one element formed by interposing a dielectric containing a capacitor paper or an organic film between two metal electrode foils and connecting and winding a plurality of lead foils to each metal electrode foil. In the low-inductance capacitor housed in the case, of the two metal electrode foils, one of the two metal electrode foils is one from the winding start side and one from the winding end side.
The lead foil is pulled out in the opposite direction by each book, and in the other metal electrode foil, the lead foil is pulled out one by one in the opposite direction to the one metal electrode foil from the winding start side and the winding end side,
The lead foil drawn from the one metal electrode foil is connected to a power supply circuit, and the lead foil drawn from the other metal electrode foil is connected to a case made of a non-magnetic metal. And low inductance capacitors.