JP2508525Y2 - Pressure contact type capacitor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial field of application) The present invention proposes a terminal structure of a pressure contact type capacitor used for applications such as filters, bypasses, couplings and blockings of electronic and electric devices. Is.

(Prior Art) A mounting method and structure of a capacitor will be described by taking a circuit of a semiconductor device as an example.

A semiconductor device using a general thyristor requires an external circuit called a commutation circuit to reduce the current in the main circuit to zero in order to shift it from an on state to an off state, and a reverse voltage must be applied to turn it off in a short time. Was needed.

Although there are various types of this commutation circuit, they are generally composed of a capacitor and a reactor, have a large mounting space, and have a drawback against the demand for downsizing of the device.

Therefore, recently, a semiconductor element such as a self-extinguishing thyristor capable of switching from an on state to an off state by applying a negative control signal to a gate terminal is positioned as one of the main devices of power electronics. As a result, it has become possible to meet the demand for miniaturization by eliminating the commutation circuit described above. In general, when a voltage exceeding an allowable withstand voltage value is applied to a semiconductor element, the semiconductor element often breaks even if the voltage is short. Therefore, when using the circuit of the inverter device,
A snubber circuit is provided to prevent these destruction phenomena. In particular, the snubber circuit is a very important protection circuit for the performance of the self-extinguishing thyristor.

The snubber circuit can suppress the overvoltage applied to the self-extinguishing thyristor by increasing the capacitance of the capacitor. However, the unnecessary increase increases the power loss consumed by the resistor. It is desirable to minimize stray inductance in the circuit and suppress overvoltage without increasing snubber capacitors.

In this sense, it is very important to shorten the wiring of the diode, the capacitor and the self-extinguishing thyristor as much as possible to reduce the inductance.

Figure 6 shows a typical self-extinguishing thyristor, eg GTO
1 shows an electric circuit of a semiconductor rectifier using a (gate turn-off thyristor), in which a gate circuit 2 for sending an ON / OFF signal is connected to a gate terminal of a GTO element 1. A snubber circuit 3 which is a protection circuit for the GTO element 1 is connected to the GTO element 1 in parallel. This snubber circuit 3
Consists of a capacitor 4 and a parallel circuit of a diode 5 and a resistor 6 connected in series with the capacitor 4.

In this case, the capacitor 4 absorbs an overvoltage such as a surge, suppresses the off-voltage increase rate dv / dt, and reduces the overvoltage applied to the GTO element 1. The diode 5 has a bypass circuit composed of a resistor 6 connected in parallel with the diode 5. The diode 5 allows a current to flow through the capacitor 4 and also serves as a backflow prevention function so that a current does not flow directly through the GTO element 1 when the capacitor 4 is discharged. .

The resistor 6 is a capacitor 4 that has absorbed an overvoltage such as a surge.
It suppresses the rising of the current so that the energy of is discharged and does not flow rapidly.

FIG. 7 is a front view of a semiconductor device in which the GTO element 1 and the snubber circuit of FIG. 6 are mounted. 4, diode 5
Attach the capacitor 4, diode 5 and heat sink
Wire 7 connects between 7A and 7K.

FIG. 8 shows a conventional cross-sectional structure of the capacitor 4. Two or more sheets of insulating thin paper (capacitor thin paper) and aluminum foil to be an electrode are superposed and wound, and a flattened capacitor element 41 is formed. The lead wire 42 is welded, connected to the terminal 44 with the insulator 43, the impregnating agent 46 is put in the case 45, and the upper lid 47 is caulked and sealed.

(Problems to be solved by the invention) The conventional capacitor shown in FIG. 8 has a lead wire 42 for connecting the capacitor element 41 and the electrode, and the inductance of the terminal 44, which is a stud, is large, and the low inductance The shape is difficult to meet the requirements.

Generally, the capacitor 4 is mounted on the panel which is the ground potential of the housing by mounting the capacitor case 45 on the panel.
Need to be insulated from. Also, a mounting leg for mounting the capacitor and a mounting man-hour are required.

Therefore, an object of the present invention is to provide a high-reliability pressure contact type capacitor by reducing the inductance of an electronic circuit and an electric circuit, greatly contributing to a reduction in size and weight.

[Means for Solving the Problems] (Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention forms a rod-shaped metal core having an insulating material having good thermal conductivity at its end and a capacitor. A metal foil having a metal foil on one side thereof, and two strip-shaped insulating films having a width substantially equal to the length of the winding core wound around the winding core, and one metal foil on each end surface of the capacitor element. In addition to applying a metallikon for spraying and connecting a metal to the metal core, an electrode made of a plate-shaped conductive metal that is closely arranged at the end of the core and soldered to the metallikon, and that this electrode protrudes from both ends. It is characterized in that it comprises a case made of an insulator to be housed, applies pressure to and supports the electrode surfaces at both ends, and radiates heat through the core and the electrodes.

(Operation) According to the present invention, by configuring as described above,
The inductance of electronic and electric circuits can be reduced, and it contributes greatly to downsizing and weight reduction, resulting in a high performance and highly reliable pressure contact type capacitor.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. 1 is a sectional view showing an embodiment of a pressure contact type capacitor according to the present invention, and FIG. 2 is a sectional view taken along the line II-II of FIG. 1 and seen in the direction of the arrow. A core 402 made of metal, in which an insulator 401 having good thermal conductivity is arranged at both ends in the axial direction, and two films 403 made of a dielectric material are wound along the outer peripheral surface of the core 402 to form a capacitor element. Make up 404. Metallicon (metal spraying) 405 is applied to both end surfaces of the capacitor element 404, and an electrode body 406, which is a copper plate, is soldered 407 to the metal layer to form an electrode 408, which is placed in a bottomed cylindrical case 409. It is configured to be housed and a resin 410 is molded inside the case 409.

The capacitor 4 configured in this way has
Although it depends on the diameter length of 402 and the insulator 401 and the material, it is easy to make a structure that can withstand ordinary electrical connection and support of its own weight. Further, the core 402, which is made of a high-voltage insulator or metal, can sufficiently withstand the pressure contact force (generally 500 kg to 2000 kg) in the coaxial direction with the diode 5 used in the snubber circuit such as the GTO element 1 in FIG. .

Furthermore, the life of the capacitor generally depends on the function of the operating temperature, and a 10 ° C increase reduces the life by 50%. As described above, the heat dissipation of the capacitor is an important elemental technology, and the core 402 can withstand the high load as described above, and also guides the heat generated from the capacitor element 404 to the electrodes by heat conduction and also plays the role of heat dissipation.

The material of the winding core 402 may be an insulating material depending on the application, and there is no particular problem.

Here, in particular, there is no hole or screw for connecting a structure such as a mounting leg for fixing the capacitor 4 itself of the present invention and an electric wire, and fixing them is mounted on a semiconductor device using a GTO element. An example will be described. Fig. 3 is 6
This is an example of mounting the snubber circuit 3 having the GTO element 1 shown in the figure, and heat sinks 7A, 7K and GT for cooling the GTO element 1
The O element 1 is held in pressure contact with the tightening device 23, the diode 5 is arranged on the anode side heat sink 7A of the GTO element 1, and the pressure contact type capacitor 4 of the present invention is arranged on the cathode side heat sink 7K. The terminal 22 for wiring to the resistor 6 and the tightening device 23 are pressed to a predetermined pressure to form a stack structure, and the mounting leg 24 is an electrically conductive material that also serves as a terminal. Connected and configured.

4 and 5 are other application examples, and FIG. 4 shows four capacitors 4 of the present invention arranged in parallel, and two capacitors 2 are provided on both sides of these capacitors.
Each of the bus bars 26 is arranged, and the bus bars 26 are used as electrodes to integrally press-contact with the tightening bolts 27.

In FIG. 5, three capacitors 4 of the present invention described above are arranged in series, and similarly to FIG. 4, the bus bar 26 and the tightening bolt 27 are pressed together. Have been.

[Advantages of the Invention] As described above, according to the present invention, specifically, the following effects can be obtained, so that it is possible to provide a compact, lightweight, high-performance and highly reliable pressure contact type capacitor.

(1) There is no lead wire between the capacitor element electrodes and they are directly connected to the metallikon by soldering, and the electrodes can be widened to reduce the inductance.

(2) Due to the pressure contact structure, the wiring of the snubber circuit such as the GTO element that requires series connection with the diode can be easily shorted and the inductance can be reduced.

(3) The lead wire connecting the capacitor element and the electrode and the stud and the insulator serving as the electrode are unnecessary.

(4) The heat generated by the capacitor element is conducted from the core to the electrodes and bus bars, and the surface area of the electrodes and bus bars can be increased, resulting in excellent heat dissipation effect.

[Brief description of drawings]

1 is a sectional view showing an embodiment of the pressure contact type capacitor of the present invention, FIG. 2 is a sectional view taken along the line II-II of FIG. 1 in the direction of the cutting arrow, and FIG. 3 is a sectional view of the present invention. Fig. 4 is a front view showing an example of mounting a capacitor on a snubber circuit of a GTO element, Fig. 4 is a perspective view showing an example of mounting a plurality of capacitors of the present invention in parallel, and Fig. 5 is a series of a plurality of capacitors of the present invention. FIG. 6 is a front view showing a mounted example, FIG. 6 is an electric circuit diagram of a GTO element snubber circuit using a capacitor, and FIG. 7 is a front view showing an example of mounting a conventional capacitor on a GTO element snubber circuit. The figure is a sectional view showing an example of a conventional capacitor. 1 ... Self-extinguishing thyristor (GTO element), 2 ... Gate circuit, 3 ... Snubber circuit, 4 ... Capacitor, 5 ...
… Diode, 6… resistor, 7A, 7K …… heatsink,
8 ... electric wire, 9 ... capacitor element, 10 ... lead wire,
402 ... Core, 403 ... Capacitor element, 405 ... Metallicon, 406 ... Electrode, 407 ... Solder, 409 ... Case, 410
...... Resin, 22 ...... Terminal, 23 ...... Tightening device, 24 ...... Mounting leg, 26 ...... Bus bar, 27 ...... Tightening bolt.

Claims (1)

(57) [Scope of utility model registration request] 1. A winding core made of a rod-shaped metal having an insulator having good thermal conductivity arranged at one end, and a metal foil forming a capacitor on one surface, and having a width substantially equal to the length of the winding core. A capacitor element in which two strip-shaped insulating films are wound around the core, and a metallikon for spraying and connecting metal to one metal foil on both end faces of the capacitor element, and an end portion of the core It is equipped with an electrode made of a plate-shaped conductive metal that is placed in close contact with the metallikon and soldered to the metallikon, and a case made of an insulator that is housed so that this electrode projects from both ends. A pressure contact type capacitor, which supports and radiates heat through the core and the electrode.