JPS636145B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor evaporative cooling device, and more particularly, to a semiconductor evaporative cooling device that utilizes a phase change between a liquid phase and a gas phase of a condensable cooling medium to cool a semiconductor and is provided with a snubber circuit. The present invention relates to a semiconductor evaporative cooling device.

Generally, a semiconductor boiling cooling device is constructed by storing a semiconductor in a sealed container, and enclosing a refrigerant, such as a condensable refrigerant such as Freon R113, in such a manner that the semiconductor is immersed therein.

In such devices, when the semiconductor generates heat due to energization, the refrigerant boils due to the heat and changes its phase from the liquid phase to the gas phase, and at this time, the semiconductor absorbs heat corresponding to latent heat, thereby Cool semiconductors. For this purpose, a condenser is installed at the top of the airtight container, and the gas phase refrigerant that has undergone a phase change inside the airtight container flows into the condenser installed at the top and transfers latent heat to the air outside the condenser. Upon release, the refrigerant is condensed and liquefied to become a liquid phase refrigerant, which returns to the sealed container. In this manner, the refrigerant circulates between the sealed container and the condenser due to the phase change between the liquid phase and the gas phase, thereby efficiently transmitting and dissipating the heat of the semiconductor contained in the sealed container to the condenser.

On the other hand, a snubber circuit is provided in parallel to the semiconductor for the purpose of suppressing surge voltage or the like.

FIG. 1 of the accompanying drawings is a configuration diagram showing an example of this snubber circuit, and in the figure, reference numeral 1 indicates semiconductors such as thyristors, gate turn-off thyristors (GTO thyristors), diodes, etc., and 2, 3, and 4 constitute the snubber circuit. 2 is a capacitor, 3 is a diode, and 4 is a resistor.

Now, semiconductor 1 turns on the DC high voltage and large current circuit.
To explain the case of a semiconductor to be turned off, such as a GTO thyristor, when a high-speed switching operation is performed, an abnormal voltage is generated across the semiconductor, and if this voltage exceeds the allowable voltage of the semiconductor, the semiconductor is destroyed. In order to absorb the abnormal voltage generated across the semiconductor, a snubber circuit shown in FIG. 1 is connected in parallel to the semiconductor 1. It is preferable that the wiring constituting the closed circuit formed by 1 and 1 be as short as possible.
When the wiring of this snubber circuit becomes long, the wiring inductance increases, the surge voltage absorption effect decreases, and there is a risk that the semiconductor 1 will be destroyed.

However, in a conventional semiconductor boiling cooling device, the semiconductor 1 is built in a sealed container, the components of the snubber circuit are installed outside the sealed container, and the semiconductor 1 is heated through an airtight bushing provided on the wall of the sealed container. Because the capacitor 2, diode 3, and resistor 4, which are the components of the snubber circuit, are connected by wiring,
There is naturally a limit to how short the wiring length can be made, and there is a drawback that the surge voltage absorption effect of the semiconductor 1 cannot be sufficiently obtained.

The structure of such a conventional semiconductor evaporative cooling device is shown in FIG. 2 of the accompanying drawings.

In the figure, reference numeral 10 is a sealed container, 11 is a condenser, 12 is a steam pipe for guiding the gas phase refrigerant generated in the sealed container 10 to the condenser 11, and 13 is a condenser 1.
1 shows a liquid pipe for returning the liquid phase refrigerant condensed in 1 to the sealed container 10. Further, the semiconductor 1 and a liquid phase condensable refrigerant 14 are sealed in the sealed container 10, and a predetermined amount of the liquid phase refrigerant 14 is poured so that the semiconductor 1 is sufficiently immersed in the liquid phase refrigerant 14. It is enclosed. Further, the upper space of the sealed container 10 and the inside of the condenser 11 are configured to be filled with the gas phase refrigerant 14a without being mixed with non-condensable gas such as air.

In addition, a bushing 1 is provided on the wall of the sealed container 10.
5 is arranged, and is electrically connected to the semiconductor 1 stored in the sealed container 10 by a conductor 16.

The conventional semiconductor evaporative cooling device is constructed as described above, and its operation will be described next.

First, when the semiconductor 1 generates heat due to electricity, etc.,
The liquid refrigerant 14 in contact with the semiconductor 1 boils,
Phase conversion from liquid phase to gas phase. At this time, heat corresponding to latent heat is removed from the semiconductor 1, so the semiconductor 1 is cooled. On the other hand, the gas phase refrigerant 14a that has undergone phase conversion and has become a gas phase rises upward due to the density difference and is guided to the condenser 11 through the steam pipe 12. Condenser 11
is composed of a large number of finch tubes 11a, and since the outside of the finch tube 11a is cooled by air, the gas phase refrigerant 14
Inside the condenser 11, a releases latent heat, condenses, and liquefies to become a liquid phase refrigerant 14.

This liquid phase refrigerant 14 returns to the sealed container 10 through the liquid pipe 13 due to the action of gravity, and cools the semiconductor 1 again.

As described above, the refrigerant 14 circulates between the sealed container 10 and the condenser 11 while undergoing a phase change, efficiently transfers the amount of heat generated in the semiconductor 1 to the condenser 11, and transfers heat from the surface of the condenser 11. dissipates into the air.

On the other hand, in the conventional device shown in FIG.
Since the semiconductor 1 is built into the inside of the sealed container 10, a snubber circuit consisting of a capacitor 2, a diode 3, and a resistor 4, which are installed outside the sealed container 10, is constructed as shown in the figure. Conductors 17a, 17 are connected between the bushing 15 and the bushing 15.
b, 17c are wired.

However, diode 3 in the snubber circuit
Although the closed circuit formed by the capacitor 2 and the semiconductor 1 requires particularly small inductance, in such a conventional device, the semiconductor 1 - conductor 16 - bushing 15
- Conductor 17a - Diode 3 - Conductor 17b - Capacitor 2 - Conductor 17c - Bushing 15 - Conductor 1
6- Since a snubber circuit is formed by the wiring path of semiconductor 1, there is a natural limit to the reduction of inductance even if the wiring is made as short as possible within this range, and as a result, the surge voltage absorption effect is insufficient. The drawback was that it was not available.

In order to improve the drawbacks of the conventional device, as shown in FIG.
7c may be considered. In addition,
The resistor 4 is installed outside the sealed container 10 and wired through the bushing 15 as shown in the figure.

According to the method shown in FIG. 3, it is possible to arrange the diode 3 and the capacitor 2 close to the semiconductor 1, and therefore, the wiring inductance can be reduced and the surge voltage absorption effect can be improved. It has the characteristic of increasing. However, this method has the following drawbacks.
That is, (1) A peak current, which is a high-frequency current of several hundred amperes, flows through a semiconductor snubber circuit that performs ON-OFF operations at high speed in a DC voltage circuit. Therefore, from the viewpoint of voltage resistance and cooling performance, a so-called oil-immersed capacitor, in which a capacitor element and insulating oil are sealed in a metal case, is used as a capacitor. In such oil-filled capacitors, the capacitor element is usually placed inside a metal case with one end open, and the open part of the metal case is closed by soldering with a metal plate called a top plate with bushings, and insulating oil is filled in. Manufactured by filling.

However, the sealed container 10 of the boiling cooling device
If the insulating oil inside the capacitor leaks and mixes with the refrigerant, the boiling cooling effect will be significantly reduced, and conversely, if refrigerant vapor enters the inside of the condenser, it will be damaged by the refrigerant, Freon. In order to avoid the risk of corrosion and deterioration of the capacitor element, the capacitor case must have a completely airtight structure. For this purpose, even if the capacitor case is sealed by soldering as in the past, sufficient airtightness cannot be ensured, so welding becomes necessary. However, for relatively small capacitors such as snubber capacitors (typically a rectangular parallelepiped of approximately 150 x 100 x 50 mm in size), if the metal case and top plate are welded together, the high temperature heat generated during welding may cause problems. Therefore, there is a risk of thermal deterioration of the internal capacitor element. Additionally, in order to prevent this thermal deterioration, it is possible to make the case larger, provide a sufficient distance between the welding point and the element, and insert an insulating material, but this would result in a significantly larger capacitor, which would be extremely difficult to achieve. This results in an uneconomical design.

(2) Capacitor elements are usually made of dielectric material such as paper or plastic, so the maximum allowable temperature of the element is relatively low, at 75 to 85°C. On the other hand, the allowable temperature for semiconductors is 125~
150°C, and the refrigerant temperature in the boiling cooling device is generally set at 70-75°C. Therefore, when a capacitor is stored in a sealed container, the wall temperature of the capacitor case becomes 70 to 75 degrees Celsius, which is the refrigerant temperature.Furthermore, due to the heat generated by the capacitor itself, the element center temperature becomes higher than the refrigerant temperature of the case, and the condenser This will exceed the allowable temperature. Therefore, in order to keep the center temperature of the condenser element below the allowable temperature, the refrigerant temperature must be set low, which requires a larger condenser, and the semiconductor evaporative cooling system itself has to be larger. This increases the weight and makes the device extremely uneconomical.

(3) When a condenser is placed in a sealed container, the sealed container becomes larger, and therefore, along with the larger condenser described in item (2) above, the semiconductor boiling cooling device becomes larger.

Furthermore, the boiling cooling device uses Freon R as a refrigerant.
-113, when the refrigerant temperature exceeds 47°C, the pressure inside the container becomes higher than the outside pressure. Therefore, boiling cooling equipment is regulated as a pressure vessel under the Industrial Safety and Health Act, but if a condenser is not housed in a sealed container, the internal volume of the container is small and it is not regulated as a pressure vessel, so it is a so-called simple container. However, by accommodating a capacitor, the internal volume of the container increases and it becomes regulated as a pressure container. As described above, when a pressure vessel is regulated, it becomes obligated to be inspected, and as a result, the manufacturing period becomes longer, the number of manufacturing steps increases, and the manufacturing cost increases.

As described above, the configuration shown in FIG. 3, that is, the method of housing the capacitor 2 and the diode 3 in the sealed container 10, is a method of shortening the wiring of the closed circuit consisting of the semiconductor 1, the capacitor 2, and the diode 3. However, on the other hand, it has the above-mentioned drawbacks and therefore can be said to be an impractical method.

The present invention improves the shortcomings of the conventional device described above, and also shortens the wiring length between the semiconductor 1 and the snubber circuit to reduce the wiring inductance, thereby providing a semiconductor suitable for improving the surge voltage absorption effect. to provide boiling cooling equipment;
That is the purpose.

In order to achieve this object, the present invention provides an open part by opening a part of a sealed container, and a case of a capacitor for a snubber circuit is joined to this open part so as to close the open part. It is characterized by:

Hereinafter, the present invention will be explained based on the attached drawing, FIG. 4, which shows one embodiment of its configuration.

In the figure, a semiconductor 1 and a snubber diode 3 are housed in a sealed container 10, and a liquid phase refrigerant 1 is housed in a sealed container 10.
Fill 4. Further, a bushing 15 is provided on the wall of the sealed container 10, and the bushing 15 and the terminal of the semiconductor 1 are connected by a conductor 16.

Moreover, the case 2i of the snubber capacitor 2 is composed of case plates 2c, 2d, and 2e,
The capacitor element 2a is housed inside a case 2i and is filled with insulating oil 2h. Further, the case plate 2c is provided with a through-through airtight bushing 2b, and the case plate 2e is provided with a through-through bushing 2f, and these bushings 2b and 2e are each connected to the terminal of the capacitor element 2a by a conductor 2g. ing.

Further, the sealed container 10 is provided with an opening 10a at a predetermined portion, and the case plate 2c of the capacitor 2 is hermetically welded to close the opening 10a.

Therefore, the hermetic bushing 2b of the capacitor 2
is configured to protrude into the sealed container 10, and is wired to the airtight bushing 2b, the terminal B of the semiconductor 1, and the diode 3 by a conductor 16a. on the other hand,
Wiring is also provided between the diode 3 and the terminal A of the semiconductor 1 using a conductor 16a.

Note that when the capacitor 2 is welded to the sealed container 10, the capacitor element 2a inside the capacitor 2 may be thermally deteriorated by the welding heat, so the capacitor 2 may be manufactured as follows.

First, the case plates 2c and 2d are joined by a method such as welding to form a case with one end open,
This case is hermetically welded and attached to the sealed container 10. Next, after storing the capacitor element 2a in this case, the capacitor element 2a is
A and the through airtight bushing 2b are connected by a conductor 2g, and a through bushing 2f installed on the case plate 2e and the capacitor element 2a are also connected by a conductor 2g. Finally, the case plate 2e is joined by a method such as soldering so as to close the open part of the case, and the case is sealed. After constructing the capacitor 2 in this way, the capacitor 2 is completed by vacuum injecting insulating oil through an oil port (not shown) and closing the oil port.

Note that it is not necessary to use an expensive airtight bushing as the bushing 2f, and an inexpensive bushing used in conventional capacitors can be used. Further, in the embodiment shown in FIG. 4, the bushing 2f is attached to the case plate 2e, but the bushing 2f is not limited to this, and may be attached to the case plate 2d. In this case, the capacitor element 2a and the bushing 2
Wiring with f can be easily done. Furthermore, the resistor 4 for the snubber circuit is connected to the semiconductor 1 by wiring a conductor 17 between one terminal and the bushing 2f of the capacitor 2 and between the other terminal and the bushing 15. A snubber circuit consisting of a diode 3, a capacitor 2, and a resistor 4 is configured.

Since the semiconductor evaporative cooling device of the present invention, particularly its snubber circuit, is configured as described above, it can achieve the following advantages. That is, (1) Since the airtight bushing 2b of the capacitor 2 is made to protrude toward the terminal of the semiconductor 1 within the sealed container 10, the wiring length of the snubber circuit is significantly reduced compared to the conventional device shown in FIG. The length can be shortened, and therefore the surge voltage absorption effect can be improved by reducing the wiring inductance.

(2) Case plate 2 on one side of case 2i consisting of case plates 2c, 2d, and 2e of capacitor 2
Since only the liquid phase refrigerant 14 in the sealed container 10 is in contact with the liquid phase refrigerant 14, the condenser 2
will be less affected by heat. Furthermore, since the heat generated by the capacitor itself is dissipated through the case plates 2d and 2e exposed to the air, the temperature of the capacitor element is lower than that shown in Fig. 3 when the capacitor is housed in a sealed container. is very low, and it is extremely easy to design the capacitor element so that its temperature does not exceed the allowable temperature.

(3) Since the capacitor is not built into the sealed container, the sealed container is small and can be made into a simple container that is not subject to the regulations for pressure vessels stipulated in the Industrial Safety and Health Act, and therefore, manufacturing The number of man-hours is small, and the production period is short, so
Economical production becomes possible.

(4) Sealed container 10 and case plate 2c of capacitor 2
Only the welded joint with the bushing 2b and the hermetic bushing 2b need be made airtight, and the other parts can be easily manufactured using conventional capacitor technology, so they can be manufactured relatively inexpensively.

(5) In the event that capacitor 2 breaks down, in the case of the improved conventional device shown in Figure 3, open the sealed container, take out the capacitor, replace or repair it, and then seal it again. However, in the device of the present invention, by separating and unsealing the case plates 2d and 2e of the case 2i of the condenser 2, the condenser element 2a can be easily replaced. possible and therefore easier to repair.

As described above, the semiconductor evaporative cooling device of the present invention has a number of features, and has the effect of providing an extremely practical semiconductor evaporative cooling device.

In the embodiment shown in FIG. 4, the capacitor 2 is disposed below the sealed container 10.
It is not necessarily limited to this, and it is possible to arrange it in any direction of the sealed container 10.

Further, although the same embodiment shows the case where the diode 3 is housed in the sealed container 10, this need not be limited to the above, and it may be installed outside the sealed container.

Furthermore, it is easy to understand that the resistor 4 may be built into the sealed container 10, and in this case, the bushing 2f of the capacitor becomes unnecessary.

Further, FIG. 4 showing the above embodiment shows the sealed container 1
0 and the capacitor 2, and any joining method or shape other than that shown in FIG. 4 will not affect the structure and effects of the present invention. .

[Brief explanation of the drawing]

Figure 1 is a circuit configuration diagram showing an example of the configuration of a semiconductor and a snubber circuit, Figure 2 is a vertical cross-sectional explanatory diagram showing the configuration of a conventional semiconductor evaporative cooling device, and Figure 3 is a diagram showing an example of the configuration of a conventional semiconductor evaporative cooling device. FIG. 4 is a vertical cross-sectional structural explanatory diagram showing one embodiment of the semiconductor evaporative cooling device of the present invention. 1...Semiconductor, 2...Capacitor, 2a...Capacitor element, 2b...Airtight bushing,
2c, 2d, 2e...Case plate, 2f, 15...
Bushing, 2h...Insulating oil, 2i...Case,
3... Diode, 4... Resistor, 10... Sealed container, 10a... Open part. In each figure, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] 1. A semiconductor and a cooling medium in which the semiconductor is immersed are stored in a sealed container, and the heat generated in the semiconductor is transferred to a condenser by utilizing the phase change between the liquid phase and the gas phase of the cooling medium. In a semiconductor evaporative cooling device that transfers heat and is provided with a snubber circuit, a part of the sealed container is opened to provide an open part, and a case of a capacitor for the snubber circuit is placed in this open part so as to close the open part. A semiconductor boiling cooling device characterized in that: 2. The capacitor case that closes the opening of the sealed container is provided with at least one airtight bushing, and any of the semiconductors in the sealed container and the snubber circuit components connected to the semiconductors are connected through this airtight bushing. 2. The semiconductor evaporative cooling device according to claim 1, wherein the capacitor and the capacitor element in the capacitor case are electrically connected. 3. The capacitor case that closes the open part of the sealed container is provided with an airtight bushing on the wall of the case in the closed part, and the bushing is provided on the wall other than the closed part. The semiconductor boiling cooling device according to item 1 or 2. 4. The semiconductor boiling cooling device according to any one of claims 1 to 3, wherein the capacitor is sealed with a coolant such as insulating oil.