JP2586482Y2 - High frequency NH 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-frequency NH capacitor having a radiation fin used as a high-voltage high-frequency capacitor.

[0002]

2. Description of the Related Art A high-voltage high-frequency capacitor used in an industrial power supply or the like uses a low-loss dielectric to prevent heat generation due to resistance loss of electrodes and to take measures against case heat generation due to high-frequency eddy current. Is a design requirement. It is difficult to satisfy such conditions with an SH capacitor using an electrode structure as a vapor deposition electrode, and an NH capacitor using an aluminum electrode as the electrode is basically used.

However, the conventional high-frequency high-frequency N
The H capacitor is, as shown in FIGS.
And aluminum electrode foils 62 are alternately stacked, and the aluminum electrode foil 62 is wound in a state of protruding from the end face to form a capacitor element 63, and a plurality of the capacitor elements 63 are connected in series and parallel as shown in FIG. It is configured. That is, FIG. 8 shows an NH capacitor in which two parallel and two capacitor elements 63 are provided. The two elements 63 are aluminum electrode foils 62 protruding from the dielectric 61 at the upper and lower ends thereof.
Portions are connected in parallel, and the two sets of elements connected in parallel are connected in series by a lead wire 64. Further, lead wires 65 for connecting a capacitor to other electronic components are provided at both ends of each of the two parallel and two series elements. The four capacitor elements connected in two-parallel and two-series in this manner are fastened together with the fastening plates 67 on both sides together with the fastening plate 67 with the separator 66 inserted in the center, and fixed together by the fastening band 68 as shown in FIG. As shown in FIG.

However, capacitors used for recent high-frequency switching power supplies have a small capacity and a high frequency, so that the current density per 1 μF increases, and in the case of a high voltage, series connection increases. The current flowing through one element is increasing. Therefore, there is a problem that the resistance loss of the aluminum electrode foil 62, the eddy current loss due to the high frequency, and the dielectric loss also increase, thereby increasing the heat generation of the capacitor element and shortening the life of the capacitor.

[0005] In particular, although a small-capacity capacitor has a small element design, heat dissipation from the case 69 is poor due to a small heat dissipation area, and convection conduction heat dissipation of insulating oil in the case 69 is limited. Therefore, it is necessary to increase the thickness of the dielectric 61 or increase the number of elements 63 in series and parallel to increase the case size and increase the heat radiation area. However, such an increase in the number of elements and an increase in the size of the case are caused by NH
There has been a problem that the size of the capacitor itself has been increased, and as a result, the size of an industrial power supply device using such a high-frequency capacitor has been increased.

Further, when the capacitor elements 63 are connected in series and parallel, the operation of connecting the individual elements 63 once in parallel and then connecting them in series as in the prior art requires the required number of capacitor elements in series and parallel. In addition, as the number of connected elements increases, the element connection work using the lead wires 64 is also required, and there is a disadvantage that the manufacture of the capacitor is complicated.

[0007]

As described above, the conventional high-voltage high-frequency capacitor has a problem that the current is increased even in the case of a small capacity, the capacitor generates a large amount of heat, and the life of the capacitor is shortened.

Means for increasing the number of elements may be considered in order to improve the dissipation of generated heat. In this case, however, the case size is large and the current market needs for which miniaturization is strongly required are considered. I could not be satisfied.

The present invention solves the above-mentioned problems of the prior art, achieves small size, light weight, long life and high reliability, and furthermore, the element connection work is easy even if the number of series-parallel connections increases. It is an object to provide a high-frequency NH capacitor.

[0010]

In order to achieve the above object, the high frequency NH capacitor of the present invention comprises a plurality of aluminum electrode foils, each of which constitutes a first to a third electrode. The first to third electrodes are superposed and wound on a dielectric material, and the first to third electrodes are connected in series to form a capacitor element. And the cooling element is integrated with the cooling plate, and the capacitor element and the cooling plate are housed in a case having a radiation fin on the surface, with the cooling plate and the radiation fin connected.

[0011]

According to the present invention having the above construction, the electrodes are formed by laminating a plurality of aluminum electrode foils, so that the resistance of each electrode is 1 / n as compared with the conventional single electrode (where n
Is the number of aluminum foils per electrode), and even if a high-frequency current flows, its resistance loss is greatly reduced.

In addition, a cooling plate is disposed integrally with the element, and heat is efficiently dissipated by the radiation fins connected to the cooling plate, even if there is resistance loss or dielectric loss, thereby suppressing heat generation of the entire capacitor. Therefore, the effect of extending the life of the capacitor and increasing the reliability can be expected.

Further, one capacitor element includes first to third capacitors.
Are connected in series to form a two-series winding structure. Therefore, even if the number of series connections is the same in the case of high voltage, the number of parallel elements can be increased, and element connection is easy. Yes, the complexity of wiring can be avoided.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be specifically described below with reference to the drawings. For comparison with the prior art, the required specification of the high-voltage high-frequency capacitor was
Assuming that the capacitor is used continuously at μF-1000 VAC and 16 KHz, the configuration of the capacitor according to the present embodiment is as shown in FIGS.

As shown in FIG. 1, the first and third electrodes 1 and 3 are each composed of 28 mm width × 8 μm thickness × two laminated aluminum electrode foils, and the second electrode 2 is 50 mm width ×
It is composed of an aluminum electrode foil having a thickness of 8 μm × two layers. The first and second dielectrics 4 and 5 superimposed on each of the electrodes 1 to 3 use a 70 mm width × 15 μm thickness × three stacked polyprolene film (hereinafter referred to as PP film). The first and third electrodes 1 and 3 are arranged such that one side edge 1a thereof protrudes 3 mm from the side edge of the dielectric body 4 and 5 at a central portion of the dielectric body 4 and 5. 3 are arranged such that a distance of 20 mm is opened between them. As a result, the first and third electrodes 1 and 3 having a width of 28 mm
However, the width of the portion facing the second electrode 2 having a width of 50 mm is 1
5 mm.

The first to third electrodes 1 to 3 and the first and second dielectrics 4 and 5 are wound 54 times in a superposed state as shown in FIGS. 1 and 2, and further wound. Thereafter, aluminum solder plating 6 is applied to the aluminum electrode foil portions of the first and third electrodes exposed at both ends thereof, thereby forming a 0.05 μF two-series wound capacitor element 10 shown in FIG.
To form Thereafter, in consideration of reduction of resistance loss and improvement of tan δ, four capacitor elements 10 shown in FIG. 3 are connected in parallel, and a 0.2 μF capacitor of 0.05 μF (two series winding elements) × 4 parallel connection is used. Get 20.

As shown in FIG. 4, the four capacitor elements 10 connected in parallel as described above are tightened with a tightening band 12 with a cooling plate 11 made of an aluminum plate interposed between both sides and each element 10. And fix it. Further, in the present embodiment, a structure in which heat radiation from each capacitor element 10 can be efficiently radiated by using a cooling plate 11 inserted between each capacitor element 10 and a radiation fin 13 integrally provided in advance is used. And Thereafter, each of the integrated capacitor elements 10 is placed in a case 14 as shown in FIG.
The NH capacitor according to the present embodiment is obtained by being housed in the inside. In this embodiment, the surface area of the case 15 is 478 cm ² .

The specifications of the capacitor of this embodiment obtained as described above are such that the rated current is about 20 A, the single-phase power is as large as 20 Kvar, and the dielectric loss is P.P. When calculated as tan δ of the P film = 0.06%, it becomes 12 watts. The equivalent resistance of one element is 1.78 × 10 ⁻⁵ Ω and 4
This parallel connection results in 4.45 × 10 ⁻⁶ Ω. As a result of stacking two aluminum electrode foils in this manner, the series equivalent resistance value of the element is reduced, and an improvement in tan δ can be expected. For example, since the series equivalent resistance of the conventional capacitor element is 2.285 × 10 ⁻⁵ Ω, in this embodiment, about 1 /
It becomes 5.

In this embodiment, the surface area of the case 15 is 478 cm ² as described above, and in this case, if the above-described heat radiation fins 13 are not provided, the temperature rise value of the case 14 is 31 deg at the upper surface of the case. there were. This temperature rise significantly shortens the life of the capacitor element, and the performance of the capacitor is lost in a short time. However, when the radiation fins 13 are provided as in the present embodiment, the temperature rise value is improved, and for example, the same surface area (478 cm
By mounting the radiation fins 13 having ² ), the temperature rise is halved and can be suppressed to about 15 deg. As a result, the life of the capacitor can be expected to be a design target value, and a high-reliability high-frequency high-frequency NH capacitor can be obtained.

On the other hand, in order to satisfy the same specification with the conventional element, as shown in FIG.
In order to form the same four elements 63 wound in a state in which they protrude, the same P.I. Using a P film having a width of 70 mm × 15 μm × 3 sheets, a thickness of 8 μm × 2 as two aluminum electrode foils 62.
Use one stack. Then, two aluminum electrode foils 62
Are shifted from each other by 10 mm inward in the width direction from the end of the dielectric 61, and are wound 58 turns so that the effective opposing width between them is 30 mm, to obtain a 0.2 μF capacitor element 63. In this case, the outer dimension of one capacitor element 63 is 76 mm × 1
It is 3 mm x 75 mm. This is made into two parallel two series,
When the connection is made as shown in FIG. 8, the total capacitance becomes 0.2 μF, which satisfies the specification. When this is stored in a case 69 as shown in FIG. 9, its outer dimensions are 90 mm × 60 mm × 1.
10 mm and the case surface area is 438 cm ² . When this capacitor is used continuously at a rated temperature, the temperature rises by 34 degrees, and the function as a capacitor is lost in a very short time due to thermal runaway.

In this conventional capacitor, since one element is 0.2 μF, when three elements are connected in parallel and three series,
F can be obtained, but in this case, the number of elements is nine, and the case size is as large as 90 mm × 140 mm × 110 mm. As the case size increases, the surface area becomes 758 cm ² , so that the temperature rise is about 20 deg, which is better than the conventional technique of the two-parallel two-series connection. However, it is still larger than the 15 deg of the present embodiment. is there. In addition, the volume of the capacitor is twice as large, which is 1.38 times as large as the size of 130 mm × 70 mm × 110 mm including the radiation fins of the present invention.

[0022]

According to the present invention, since the heat generated from the capacitor element can be efficiently dissipated without increasing the size of the entire capacitor, the life of the capacitor can be extended and the reliability can be improved. As a result, it is possible to obtain a compact and lightweight high-frequency NH capacitor having a tan δ characteristic equal to or higher than that of the conventional high-frequency NH capacitor.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a capacitor element constituting a high-frequency NH capacitor according to the present invention, particularly showing an arrangement of a dielectric and an aluminum electrode constituting the capacitor element.

FIG. 2 is a developed view in which a dielectric and an aluminum electrode foil of the capacitor element of FIG. 1 are unwound.

3A and 3B show a state after winding of the capacitor element of FIG. 1, wherein FIG. 3A is a plan view and FIG. 3B is a front view.

4A and 4B show an example of an NH capacitor using the capacitor element shown in FIG. 1, wherein FIG. 4A is a plan view and FIG. 4B is a front view.

5A and 5B show a state in which the NH capacitor of FIG. 4 is housed in a case, wherein FIG. 5A is a plan view and FIG. 5B is a front view.

FIG. 6 is a cross-sectional view showing an example of a capacitor element constituting a conventional high-frequency NH capacitor, and particularly showing an arrangement of a dielectric and an aluminum electrode constituting the capacitor element.

FIG. 7 is a developed view in which the dielectric and aluminum electrode foil of the capacitor element of FIG. 6 are unwound.

FIG. 8 is a plan view showing an example of an NH capacitor using the conventional capacitor element of FIG.

9A and 9B show a state in which the NH capacitor of FIG. 8 is housed in a case, wherein FIG. 9A is a plan view and FIG. 9B is a front view.

[Explanation of symbols]

 1-3: first to third electrodes 4, 5: dielectric 6: aluminum solder plating 10: capacitor element 11: cooling plate 12: fastening band 13: radiation fins 14: case

Claims (2)

(57) [Scope of request for utility model registration] A first to third electrodes are formed by laminating a plurality of aluminum electrode foils, and the first to third electrodes are superposed on a dielectric and wound, and the first to third electrodes are wound. To the third electrode are connected in series to form a capacitor element, a plurality of these capacitor elements are connected in parallel, these capacitor elements are integrated with a cooling plate, and these capacitor elements and the cooling plate are radiated to the surface. A high-frequency NH capacitor, wherein the cooling plate and the radiation fin are connected and housed in a case having fins. 2. The first and third electrodes are spaced apart from each other at the center in the width direction of the dielectric, and at one side edge of the dielectric, one side edge of each electrode foil is connected to one side of the dielectric. The second electrode is overlapped on one surface of the dielectric so as to protrude from the side edge, and the first and third electrodes are sandwiched between the dielectrics such that both side edges are inside the both sides of the dielectric. 2. The high-frequency NH capacitor according to claim 1, wherein the high-frequency NH capacitor is superimposed on a surface on the opposite side.